Posts Tagged ‘ovarian cancer’

Almudena’s Story:  A Life of Hope, Rejuvenation and Strength

Author: Gail S. Thornton, M.A.

Co-Editor: The VOICES of Patients, HealthCare Providers, Caregivers and Families: Personal Experience with Critical Care and Invasive Medical Procedures

Patient had ovarian clear cell adenocarcinomas (OCCAs) and underwent a complete hysterectomy at age 52. Interview was conducted 15 months’ post-surgery. Earlier in life, patient had thyroid cancer and removal of her thyroid gland and all the lymph nodes in her neck.


Almudena Seeder-Alonso, originally from Madrid, Spain, and now living in Amsterdam, The Netherlands, with her Dutch husband, René, is the eternal optimist, embracing life, reinventing herself, and looking for opportunity in every moment. She is an influential blogger of international relations issues, a career professional in human resources management in both corporate and consulting businesses in Legal, Accounting and Technology, and a lawyer and political scientist with an advanced degree in international relations who is also pursuing a Ph.D. in international relations and diplomacy. And she speaks four languages fluently – Spanish, Dutch, Portuguese and English.

Her story is one of hope, rejuvenation and strength that defines her effervescent personality. One year ago, a routine gynecology exam changed her outlook and perspective on life. She would have never thought that her diagnosis would be ovarian carcinoma of the clear cell, the most aggressive form of cancer.


Image SOURCE: Photographs courtesy of Almudena Seeder-Alonso. Top Left: Almudena’s parents, María and Angel, and sister, Cristina, and her husband. Top Right: Almudena during chemotherapy last summer (2015). Middle: Almudena attending a wedding in Asturias (northwest Spain – May 2016), Almudena and René in Comporta, Portugal (Summer 2014) and in New York (April 2014). Below left: Almudena in New York (April 2014). Below Right: Almudena’s sisters, María and Cristina with nephew, Jaime (May 2016). 

A Small Cyst Turns Into Diagnosis of Ovarian Cancer

In early 2015, Almudena visited her gynecologist in Amsterdam for a regular, yearly appointment.

“I was feeling fine. I had no physical complaints, except for my monthly periods which were heavy. I didn’t think much about it. During my examination, my doctor told me that she found a small cyst on my right ovary and we would just observe it to make sure it was not growing.”

Almudena went back to her gynecologist at the OLVG (Onze Lieve Vrouw Gasthuis in Amsterdam twice over the next month to monitor the cyst, only to find that the cyst was growing slightly. Her gynecologist recommended blood tests, an ultrasound, and a specimen of the cyst to be removed through a laparoscopy, a procedure requiring small incisions made below the navel using specialized tools.

“The pathology report said that the cyst was an aggressive cancer, called ovarian carcinoma of the clear cell. I remember sitting in my doctor’s office once she told me the results of the test, and I got very quiet. I could not believe that this was happening to me. While I was meeting with the doctor, I called my husband to let the doctor inform him about the situation. I was listening to this conversation but from far away. He immediately left his meeting with his client (he is one of two founding partners of SeederdeBoer, a Dutch Consulting & Technology firm), to come home. I left the doctor’s office, went home and cried in my husband’s arms.”

Almudena then called her parents, María and Angel, and her two sisters, María and Cristina who live in Madrid, to tell them the news.

“My Mother was very emotional when she heard about my diagnosis. My Father, who is a quiet man by nature, asked me, ‘How could this be happening to you again?’ I did not have an answer for him.”

Almudena’s father was referring to his daughter’s diagnosis of thyroid cancer in her late 20s.

Diagnosis of Thyroid Cancer As A Young Woman

When Almudena was 27 years old, she was diagnosed with follicular thyroid cancer, a slow-growing, highly treatable type of cancer that forms in follicular cells in the thyroid gland. After a 12-hour surgery to remove the gland through a procedure called a full thyroidectomy, she also needed radiation therapy. Many years later, she is feeling fine and continues to be on thyroid medication for the rest of her life.

“I was not aware at that young age of the scope of the diagnosis, but my life really changed. I was kind of a party animal at the end of the 1980s, and I did not have any amount of energy for that anymore. I needed several months to get back into shape as the scar from the surgery was a large one on the right side of my neck. I could not use my right arm and hand properly for months, even writing was complicated. The worst news came later when I could not get pregnant given the situation that many of my eggs were gone because of radiation. At that moment, egg freezing technology was not as advanced as it is today; it was not normal to freeze eggs for a later time. That was really painful, as I could not become a mother, even after four in vitro fertilization (IVF) cycles.”

According to the National Cancer Institute’s web site, thyroid cancer is a disease in which malignant cancer cells form in the tissues of the thyroid gland. The thyroid is a gland at the base of the throat near the trachea (windpipe). It is shaped like a butterfly, with a right lobe and a left lobe. The isthmus, a thin piece of tissue, connects the two lobes. A healthy thyroid is a little larger than a quarter coin. It usually cannot be felt through the skin. The thyroid uses iodine, a mineral found in some foods and in iodized salt, to help make several hormones. Thyroid hormones control heart rate, body temperature, and how quickly food is changed into energy (metabolism) as well as, it controls the amount of calcium in the blood.

Ovarian Cancer Diagnosis Continues

Almudena then spoke with her physicians in Madrid, as that is where she grew up, to get a second opinion about her ovarian carcinoma diagnosis. The physicians knew her history well and they told her that they did not believe that the follicular thyroid cancer was directly related to the ovarian cancer.

“My local gynecologist in Amsterdam then referred me to a specialist, Dr. J. van der Velden, a gynecologist/oncologist at the Amsterdam Medisch Centrum (AMC),, one of the top university hospitals in The Netherlands for this surgery and treatment. My husband, René, and I met with Dr. van der Velden, and he told us that my cancer was a fast-spreading condition and I needed to have it removed immediately. He answered our questions, calmed my fears and said he would do everything to help me.

“I have an open attitude towards people so it was easy to create a good connection with the doctors and medical personnel, which I consider very fundamental in such a process. I talked to them about my concerns or doubts and shared my worries about the process that I was going through. I have to say that all of them were wonderful in every aspect!”

Dr. van der Velden explained to Almudena that as clear cell is an aggressive form of ovarian cancer, it would need to be treated that way. One month later, Almudena underwent a procedure called open surgery, rather than laparoscopic surgery, requiring an incision large enough for the doctor to see the cyst and surrounding tissue.

“My incision from the surgery is a constant reminder of the struggle I went through. The cyst, which was 3cm, was a solid mass on my right ovary. It had adhered itself to the ovary and had to be broken to be removed, so some cells spilled out into my reproductive organs, namely, in my uterus and fallopian tubes. During this surgery, which was a complete hysterectomy, the doctor took additional tissue samples of my reproductive organs to be analyzed by pathology. Weeks later, he found no other metastases or extra cancer cells.”

The Process of Healing Begins

One month later, Almudena’s body was still recovering from the operation. Now, she had to start chemotherapy back at the OLVG.

“The doctor, Dr. W. Terpstra, hematologist/oncologist instructed me that I would be going through six full cycles of chemotherapy, which means full doses of carboplatin & paclitaxel every 21 days. At first, I felt reasonably good, then as each week progressed, I became more and more tired, nauseous, and just feeling terrible. I was not sleeping well and even lost the sensation of my fingers and toes as chemo attacks the nerves, too. Then, I started losing my eyelashes and hair so I shaved my long, flowing hair and wore a scarf wrapped around my head.”

Almudena would report to the hospital for her weekly chemotherapy session, starting at 9am and leaving at 6pm. The medical team would put her in a room with a full-size bed so she can relax during the infusion. Her husband, two sisters and some close friends would take turns accompanying her during this time, as she had a nurturing and caring support network.

“I could not have gone through this condition without my family and friends. It tests your relationships and shows you who your friends really are.”

The chemotherapy affected Almudena’s red blood cell count halfway through the process and she felt weak and tired.

“Anemia is normal during this time, but always being tired made me concentrate and focus on things less. I would watch a movie or read a book through the chemo session, and then I would fall asleep quickly.”

After Almudena finished the complete cycle of chemotherapy infusions, she had a follow-up appointment with her doctor, which included blood work, CT scan, and other diagnostic tests.

“My doctor said the tests results were very good. Now, I see him every three months for a routine visit. That was such a wonderful report to hear.

“During this process I learned to love myself, and pampered myself and my body. I learned to improve in terms of beauty, even in the worst circumstances. I wanted to feel beautiful and attractive for myself and for my close family. After three chemo cycles, I started even to think about how my new hair style would be in the moment that I finished chemo.”

Ovarian Carcinoma Pathophysiology Facts

According to published studies, ovarian clear cell adenocarcinomas (OCCAs) account for less than 5 percent of all ovarian malignancies, and 3.7–12.1 percent of all epithelial ovarian carcinomas. By contrast, early‐stage clear cell ovarian cancer carries a relatively good prognosis. When compared with their serous counterparts, a greater proportion of OCCA tumors present as early‐stage (I–II) tumors, are often associated with a large pelvic mass, which may account for their earlier diagnosis, and rarely occur bilaterally. Very little is known about the pathobiology of OCCA. Between 5 percent and 10 percent of ovarian cancers are associated with endometriotic lesions in which there is a predominance of clear and endometrioid cell subtypes, suggesting that both tumor types may arise in endometriosis.

The National Cancer Institute’s web site offers these statistics. In most families affected with the breast and ovarian cancer syndrome or site-specific ovarian cancer, genetic linkage has been found to the BRCA1 locus on chromosome 17q21. BRCA2, also responsible for some instances of inherited ovarian and breast cancer, has been mapped by genetic linkage to chromosome 13q12. The lifetime risk for developing ovarian cancer in patients harboring germline mutations in BRCA1 is substantially increased over that of the general population.

Words Of Wisdom

“Throughout this journey, I found myself again in some way and found my strength as well. When it seemed I could not stand it anymore, either physically and mentally, I realized that I could.

“At the beginning of my diagnosis, I asked myself, ‘Why me?’, and I then changed it to, ‘Why not me?’ I discovered that I have the same opportunities as anyone who becomes ill. The important perspective to have is not whining and dwelling on my bad luck. The important thing is to heal, survive, and recover my life, which is very good!

“I learned the real value and importance of things: to differentiate and give real meaning and value to the care and support of my husband, René, who was always there for me, and my parents and sisters, who came to Amsterdam very often during the process. I also made sure that René was well-supported and accompanied by my family.  René was feeling terrible for me, but he never showed it — and I learned this fact after I was starting to be back on track.”

Almudena’s Life Today

“At a significant moment in my life during my cancer diagnosis and after a long professional life in many corporate and consulting business in several countries, I decided to re-invent myself and start a new career, this time, in the battle of the opinions. I always liked foreign affairs and diplomacy, so why not share my thoughts and write about current international issues.”

That’s when Almudena started a blog to discuss relevant international political issues with her background specialization in International Relations, International Politics, International Law and Governance.

“I consider myself politically liberal and have been influenced by J.S. Mill and A. Tocqueville’s tradition of thought, as well as their ethical conception of the defense of freedom. This is what I try to capture in my political approach and in this blog.

“Regarding my profession, I have already reinvented myself, leaving the corporate life with all that is included regarding life’s standards, and do what really makes me happy, which I´m doing right now. It seems after all, looking back with perspective, I did the right thing.

“I am grateful for my life and never take anything for granted. I am the happiest when I am doing things that please me or give me the utmost satisfaction. I now have balance in my personal and professional life, something that I’ve never had before. My husband, René, likes it too and I have his full support.”

She recently ‘liked’ this saying on LinkedIn, the professional network site, ‘I never lose. I either win or learn,’ which was attributed to Nelson Mandela, the deceased South African anti-apartheid revolutionary, politician and philanthropist.

Almudena’s life continues on a path of balance, richness and thankfulness for the person she is and the many blessings she continues to have along the way.

Editor’s note:

We would like to thank Gabriela Contreras, a global communications consultant and patient advocate, for the tremendous help and support she provided in locating and scheduling time to talk with Almudena Seeder-Alonso.

Almudena Seeder-Alonso provided her permission to publish this interview on August 10, 2016.


Other related articles on the link between Ovarian Cancer and Thyroid Cancer:

Other related articles/information:


Other related articles on Ovarian Cancer and Thyroid Cancer were published in this Open Access Online Scientific Journal include the following: 

Ovarian Cancer (N = 285)


A Curated History of the Science Behind the Ovarian Cancer β-Blocker Trial

Model mimicking clinical profile of patients with ovarian cancer @ Yale School of Medicine


Preclinical study identifies ‘master’ proto-oncogene that regulates stress-induced ovarian cancer metastasis | MD Anderson Cancer Center

Good and Bad News Reported for Ovarian Cancer Therapy

Efficacy of Ovariectomy in Presence of BRCA1 vs BRCA2 and the Risk for Ovarian Cancer


Thyroid Cancer (N = 124)
Experience with Thyroid Cancer



Thyroid Cancer: The Evolution of Treatment Options


Read Full Post »

Targeting PARP

Curator: Larry H. Bernstein, MD, FCAP




Targeting PARP in Prostate Cancer: Novelty, Pitfalls, and Promise    
Review ArticleMay 15, 2016Oncology Journal, Prostate Cancer

© 2016 Steve Oh and Myriam Kirkman-Oh, KO Studios

Metastatic prostate cancer remains a highly lethal disease with no curative therapeutic options. A significant subset of patients with prostate cancer harbor either germline or somatic mutations in DNA repair enzyme genes such as BRCA1, BRCA2, or ATM. Emerging data suggest that drugs that target poly(adenosine diphosphate [ADP]–ribose) polymerase (PARP) enzymes may represent a novel and effective means of treating tumors with these DNA repair defects, including prostate cancers. Here we will review the molecular mechanism of action of PARP inhibitors and discuss how they target tumor cells with faulty DNA repair functions and transcriptional controls. We will review emerging data for the utility of PARP inhibition in the management of metastatic prostate cancer. Finally, we will place PARP inhibitors within the framework of precision medicine–based care of patients with prostate cancer.

In 2016, prostate cancer is expected to be diagnosed in 180,890 men, and 26,120 will die of metastatic disease.[1] While the majority of localized prostate cancers can be controlled with surgery and/or radiation, metastatic disease remains a lethal disease with no curative options. Moreover, prostate cancer is a heterogeneous disease that can be highly lethal but also slow and indolent, as reflected by a 10-year estimated survival of 17% (S9346 trial, unpublished data). The advent of affordable and efficient techniques for profiling tumors molecularly represents an unprecedented opportunity to better characterize the molecular factors that result in indolent and/or lethal disease and to tailor therapy accordingly. Many clinical trials are already underway to examine whether molecularly targeted therapies can improve outcomes.[2] In this review, we will specifically examine the molecular rationale for one of these targeted approaches, poly(adenosine diphosphate [ADP]–ribose) polymerase (PARP) inhibition, in prostate cancer. We will review how PARP inhibitors function as a class, review the molecular features that sensitize cancer cells to this therapy, and discuss the data supporting its potential for patients with prostate cancer. We will then outline a strategy for further development of PARP inhibitors in the prostate cancer field.
Metastatic prostate cancer is typically categorized as hormone-sensitive prostate cancer (HSPC), which responds to androgen ablation, or castration-resistant prostate cancer (CRPC), which develops resistance to gonadal suppression. Although bilateral orchiectomy is the historic gold-standard treatment for metastatic HSPC, gonadal suppression is currently accomplished with gonadotropin-releasing hormone agonists or antagonists with or without androgen receptor blockade. This approach remains the cornerstone of therapy for men with metastatic HSPC.[3] Emerging data from large phase III trials (CHAARTED and Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy [STAMPEDE]) have also revealed a large survival benefit for the combination of docetaxel and androgen deprivation in metastatic HSPC.[4,5]

Despite these initially effective treatments, the vast majority of men with metastatic HSPC will progress to CRPC, which is the lethal stage of the disease. For these patients, several additional therapies provide benefit by further suppression of androgen signaling (enzalutamide, abiraterone), disruption of the cell cycle in replicating cells (docetaxel, cabazitaxel), targeting of bone metastases (radium-223), or activation of antitumor immunologic response (sipuleucel-T).[6] While these therapies have undoubtedly extended the median survival of patients with metastatic CRPC, their impact on survival is modest and they clearly do not work for all men. In addition, we lack validated genomic markers that would allow better selection of patients for these therapies. Therefore, a better approach that leverages the individual and unique aspects of a patient’s cancer and utilizes therapy based on these factors may allow us to improve patient outcomes.

The development of high-throughput sequencing technology has made it feasible to comprehensively analyze the genetic mutations and gene expression changes in individual prostate cancers with a high degree of resolution in real time. Many institutions now routinely perform these analyses in the hope that they might uncover molecular features that predict response to certain therapies or provide guidance for clinical trial selection.[7] This approach, colloquially termed “precision” medicine, offers the potential promise of providing the right therapy for the right patient at the right time. In the context of prostate cancer, it means molecularly characterizing a tumor and then offering patients drugs that may specifically promote tumor lethality based on these molecular features. The limitation of this approach is that it requires that the target be truly biologically relevant and that there are drugs that can effectively target these molecular changes. The discovery of both somatic and germline DNA repair deficiencies in prostate cancer, together with the development of PARP inhibitors that can kill cancer cells with these defects, is a potent example of targeting therapy to molecularly defined tumor subtypes. While much early work validating this approach has occurred in breast and ovarian cancer populations, emerging data suggest that PARP inhibition is a potentially important strategy for managing a significant subset of prostate cancer patients.


PARP Inhibition: Targeting DNA Repair Deficiency

Molecular mechanism

PARP1 catalyzes the addition of poly(ADP)-ribose (PAR) groups to target proteins in a process termed PARylation.[8] PARP1 is part of a superfamily of proteins that consists of 18 members (including the related tankyrase enzymes), which have many functions within normal and cancer cells. PARP1, the founding member of this family, is responsible for the majority of PARylation of protein targets within cells. It is primarily present in the nucleus in association with chromatin, where it participates in DNA repair and regulation of gene expression by modulating protein localization and activity.[9]

DNA damage occurs continuously in all living cells as a result of oxidative damage or DNA replicative stress.[10] When DNA damage occurs on one strand of the DNA double helix, a single-strand break (SSB) results, but if two SSBs occur in close proximity and on opposite strands, the result is a double-strand break (DSB) and discontinuity of the chromosome (Figures 1 and 2). Even a single DSB is lethal to a human cell if unrepaired because of the risk of large-scale loss of genetic information.

PARP1 plays a critical role in restoration of genomic integrity by facilitating efficient repair of DNA SSBs and DSBs. PARP1 senses DNA damage by binding to the site of SSBs and DSBs and inducing auto-PARylation, which in turn promotes recruitment of DNA repair factors (such as DNA ligase III, polymerase β, and x-ray repair cross-complementing protein 1[XRCC1]).[11] Loss of PARP1 function by means of pharmacologic or genetic mechanisms results in impaired SSB repair and, following initiation of DNA replication, creation of a DNA DSB (see Figure 1). PARP may also play an important role in DSB repair and is known to recruit the MRE11-RAD50-NBS1 complex and to promote PARylation of BRCA1, factors required for the homologous recombination (HR) pathway of DNA DSB repair. Therefore, pharmacologic inhibition of PARP1/2 in DNA repair–defective (DRD) cells that lack efficient HR repair capabilities (such as those harboring BRCA1, BRCA2, or ATM mutations) results in failure to resolve SSBs, which are then converted to DSBs that promote cellular death.

The activity of PARP1 is not limited to DNA damage response. PARP1 is also known to regulate gene expression by modulation of transcription factor activity and regulation of chromatin.[12] PARP1 binds to RNA polymerase II, regulating gene expression, and may also affect tumor suppressor and oncogenic gene expression. PARP1 can also modulate hormone-dependent gene transcription from hormone-responsive nuclear receptors, such as estrogen receptors α and β, progesterone receptor, and androgen receptor.[9]

Furthermore, PARP1 can modulate the transcriptional activity of ETS transcription factors, which suggests that pharmacologic targeting of PARP1 may be useful in TMPRSS2:ERG fusion–positive prostate cancer cells (~50% of prostate cancers).[13] PARP1 physically interacts with the TMPRSS2:ERG gene fusion and the DNA–protein kinase complex, and these interactions are required for ERG-related gene transcription. Interestingly, PARP inhibition with olaparib inhibited prostate cancer xenograft growth if tumors harbored a TMPRSS2:ERG fusion, which suggests that PARP might represent a therapeutic option for prostate cancer patients withTMPRSS2:ERG fusions.[13] This concept is being evaluated in a recently completed clinical trial (National Cancer Institute [NCI] 9012).

PARP inhibitors

Given the biologic importance of PARP1 in the context of cancer, several pharmacologic agents that target this enzyme are currently under development (Table). Most PARP inhibitors mimic the NAD+ substrate of PARP1, competitively bind to the catalytic domain, and inhibit PAR synthesis.[14] PARP inhibitors require the expression of PARP1 and PARP2, and cells that lack expression of both genes are not sensitive to these agents. PARP inhibitors all appear to block catalytic activity and PAR synthesis in a roughly equivalent manner but may show differential ability to trap PARP1/2 at the site of DNA damage (niraparib > olaparib > veliparib), an event that blocks repair and promotes cellular lethality.[15,16] Whether these effects observed in vitro translate into clinically meaningful differences in efficacy is less clear. Furthermore, it is also now clear that the putative PARP inhibitor iniparib may not promote cytotoxicity via PARP inhibition. Several initial studies focused on iniparib, but when phase III trials failed to demonstrate the efficacy of this compound, additional mechanistic work demonstrated that iniparib may not truly be an effective PARP inhibitor.[17,18] These data illustrate the necessity of careful mechanistic characterization of any targeted agent prior to large-scale and expensive studies.

Germline DNA repair deficiency

Inherited defects in DNA repair pathways result in increased susceptibility to the development of malignancy.[19] Defects in mismatch repair proteins promote the development of tumors, including colon and uterine,[20] whereas inherited inactivating mutations in BRCA1 and BRCA2, which are required for efficient HR-based DNA DSB repair, significantly increase the risk of breast, ovarian, prostate, and other cancers.[21] Patients with these tumor types typically demonstrate homozygous inactivation of these genes, the first event occurring in the germline, with subsequent clonal somatic inactivation of the remaining allele.[21] These events presumably occur early in tumorigenesis and, by loss of robust DNA DSB repair, induce genomic instability, which causes loss of tumor suppressors, activation of oncogenes, and acceleration of tumorigenesis.

A germline mutation in BRCA1 or BRCA2 increases the risk of prostate cancer and thus may be found in 2% to 5% of prostate cancers.[22,23] The relative risk of development of prostate cancer for men ≤ age 65 with BRCA1 mutations is 1.8, but BRCA2 mutations in particular seem to increase the risk of prostate cancer formation by age 65 by about 8.6-fold. Mutations of BRCA1, BRCA2, and ATM (and perhaps other DNA repair genes) may also play a role in progression to the lethal castration-resistant state.[22,24-26] The frequency of BRCA2 germline mutations in prostate cancer alone may be as high as 2%.[22] Therefore, the development of therapies to target DNA repair is likely to benefit a relatively large and relatively young population.

Somatic DNA repair deficiency

In addition to germline defects, tumors can acquire defective DNA repair processes through somatic loss of DNA damage response genes, and these somatic mutations can also confer sensitivity to PARP inhibition.[27] This has led to the concept of “BRCAness,” which refers to somatically acquired defects in HR that, as a group, could predict tumor response to PARP inhibitors and cisplatin.[21] Somatic alterations can include either acquired mutations or epigenetic events that silence genes such as ATM; ATR; BRCA1 or –2; CHEK1 or -2; FANCA, -C, -D2, -E, -F; PALB2; MRE11 complex; or RAD51, which prevent efficient HR repair of DNA DSBs.

It is likely that a substantial proportion of men with prostate cancer may demonstrate aspects of BRCAness that could predict sensitivity to PARP inhibitors. Beltran et al performed targeted next-generation sequencing of tumors from men with advanced prostate cancer and found that 12% demonstrated BRCA2 loss and that 8% harbored ATM loss.[28] Furthermore, up to 19.3% of CRPCs demonstrate aberrations in BRCA1, BRCA2, or ATM; these events become more frequent as the disease progresses from hormone-sensitive to castration-resistant.[29] Together these data suggest that BRCAness is a reasonably frequent event in patients with advanced prostate cancer, which makes PARP inhibition an attractive target in this disease.

Synthetic lethality

The concept of promoting the killing of cancer cells by simultaneously blocking SSB repair using PARP inhibition in cells that lack efficient DSB repair is called “synthetic lethality.” In this scenario, tumor cells may harbor either germline or somatically acquired homozygous inactivation of HR. Germline defects (when present) typically affect only one allele in normal cells, and therefore normal tissues retain HR function. This difference between the DNA repair capacity of normal and cancer cells can be leveraged to produce selective cell killing of tumor cells by PARP inhibitors. Treatment of patients with PARP inhibitors will then block normal SSB repair in all cells, and these SSBs are subsequently converted to DSBs by DNA replication. In normal cells, HR restores the genome and allows survival, but in DRD cancer cells, DSBs persist, inducing cellular death selectively in the tumor cell population (see Figure 2).

Early-phase studies

Ample data indicate that PARP inhibitors possess antitumor activity within diverse patient populations, particularly those with BRCA1 or BRCA2 mutations.[14] One of the first studies to validate the concept of clinical benefit in patients with BRCA mutations was a phase I trial that looked at pharmacokinetic and pharmacodynamic aspects of olaparib treatment.[24] In this study, 60 patients with solid tumors were treated with various doses of olaparib (10 mg daily to 600 mg twice daily) to determine maximum tolerated dose (MTD). The study population was intentionally enriched for BRCA mutation carriers, and 22 patients of the cohort harbored BRCA1 or BRCA2 mutations. Objective tumor activity was observed in the mutation carrier population in patients with breast, ovarian, and prostate cancers. Three patients with advanced prostate cancer were included in this study cohort; the one with a BRCA2 mutation had a greater than 50% response in prostate-specific antigen (PSA) level, resolution of bone metastases, and an extended treatment course. This study suggested that there was a benefit of olaparib therapy in BRCA mutation carriers and the potential for benefit in prostate cancer patients. Further validation of olaparib efficacy in patients with BRCA mutations came from parallel proof-of-concept studies demonstrating the activity of this agent in women with breast and ovarian cancers and BRCA1 or BRCA2 mutations.[30,31] These data ultimately led to US Food and Drug Administration (FDA) approval of olaparib for women with a BRCA mutation and metastatic ovarian cancer after chemotherapy.
Additional data that demonstrate a similar spectrum of activity are available for other PARP inhibitors. Phase I data on the safety and pharmacodynamics of single-agent veliparib have been reported as an abstract,[32] and additional studies of veliparib in combination with mitomycin,[33] irinotecan,[34] and other agents have been reported.[35] VanderWeele et al published a case report of a patient with metastatic CRPC and BRCA2 mutation who had a sustained complete response to veliparib and carboplatin/gemcitabine.[36] It seems likely that many of the available PARP inhibitors may have overlapping activities, and further data will be needed to clarify which agent to use in which tumor type and the relative toxicities of each agent.

emozolomide and veliparib in metastatic CRPC

Compelling data implicate PARP1 in the mediation of DNA repair responses to alkylating agents,[37] cellular survival in BRCA-deficient cells,[24,38] and androgen receptor–mediated prostate cancer cellular proliferation.[9,39] Furthermore, data suggest that prostate cancers that harbor the TMPRSS2:ERG fusion (present in up to 50% of prostate cancers) may be more sensitive to PARP inhibition.[13] Therefore, Hussain et al carried out a single-arm pilot study to assess the safety and efficacy of veliparib with the alkylator temozolomide (TMZ) in patients with metastatic CRPC following docetaxel therapy.[40] In this study, patients with a PSA level of ≥ 2 ng/mL were treated with veliparib, 40 mg twice daily, on days 1 to 7 and TMZ, 150 to 200 mg/m2, on days 1 to 5 on a 28-day cycle, based on tolerance data from a phase I study ( identifier: NCT00526617). The primary endpoint was PSA response rate (30% decline). Of the 25 patients who were evaluable for response, 2 had a confirmed response, 13 had stable PSA, and 10 had progression. The most frequent toxicities were thrombocytopenia, anemia, fatigue, neutropenia, nausea, and constipation. The investigators did assess frequency of TMPRSS2:ERG fusion but found it in only one of eight evaluable patients. Although this patient had stable disease, no conclusions could be drawn regarding the contribution of the fusion product to veliparib sensitivity. Overall, while the combination was considered tolerable, it had only modest activity. No preselection was done in the study, and because BRCAness exists in 20% of patients, it is perhaps not surprising that activity was modest. The lower dose of PARP inhibitor and the lack of established benefit for TMZ may also have contributed to less than robust clinical activity for this combination. Given the emerging molecular data, it seems that future studies will be more likely to identify activity if done in preselected patient populations.


The Trial of PARP Inhibition in Prostate Cancer (TOPARP-A) sought to determine whether patients with prostate cancers with molecularly identified defects in DNA repair benefited from full-dose olaparib therapy.[25] In this phase II study, 50 men with CRPC underwent biopsy of metastatic disease and targeted next-generation sequencing, exome and transcriptome analysis, and digital polymerase chain reaction. The primary endpoint was response rate (either objective response or reduction of 50% in PSA level or reduction in circulating tumor cells). All had previously received docetaxel, and most had been treated with abiraterone or enzalutamide (98%) and cabazitaxel (58%). Patients were grouped according to the presence or absence of a homozygous deletion of or deleterious mutation in DNA damage response genes, which predict sensitivity to PARP inhibition. Overall, 16 of 49 evaluable patients (33%) were biomarker positive (indicative of homozygous deleterious changes in BRCA1/2, ATM, Fanconi anemia genes, or CHEK2). Of these, five patients had germline and somatic events (three patients with germline BRCA2 and three patients with germline ATM deletions or mutations). Of the 16 patients with deleterious changes in DNA repair genes, 14 (88%) responded to olaparib. The median overall survival for patients with biomarker-positive DRD tumors who received olaparib was 13.8 months, compared with 7.5 months for those with biomarker-negative tumors (P = .05). Interestingly, two biomarker-negative patients also met criteria for response to olaparib. Although one was a longer-term responder still on therapy at the time of publication, this particular patient did harbor monoallelic deletions of both BRCA2 and PALB2 that did not meet criteria for the prespecified biomarker-positive category but that may have contributed to tumor sensitivity. Toxicity was as expected, with patients displaying grade 3 or 4 anemia (10/50), fatigue (6/50), leukopenia (3/50), thrombocytopenia (2/50), and neutropenia (2/50). These results illustrate the feasibility of using molecular profiling to identify prostate cancers that display molecular features suggestive of sensitivity to PARP inhibition (BRCAness).

NCI 9012

ETS gene fusions—which result from gene rearrangement and juxtaposition of an androgen-responsive gene, such as TMPRSS2, to an ETS transcription factor gene, such as ERG or ETV1—occur in 50% to 60% of prostate cancers.[41,42] ETS transcription factors may also physically interact with PARP1, and PARP1 activity may be required for ETS-mediated invasion, transcription, and metastasis.[13] Androgen receptor–mediated transcription may also promote DNA DSBs and requires PARP activity for efficient repair.[43-45] Therefore, therapeutic targeting of androgen receptor signaling and PARP1 activity using abiraterone and veliparib is an attractive strategy in the management of metastatic prostate cancer.

A randomized phase II clinical trial in patients with metastatic CRPC was recently completed; it examined whether ETS fusion is a biomarker of response to abiraterone or abiraterone plus veliparib. In this study, 148 patients with metastatic CRPC underwent biopsy followed by assessment of ETS fusion status and then random assignment to either abiraterone alone or abiraterone plus veliparib. The primary endpoint was confirmed PSA response in patients receiving either abiraterone alone or combination therapy, stratified by ETS status. Secondary endpoints included safety, objective response rate, progression-free survival, and whether DNA repair gene deficiency (homozygous deletions of or deleterious mutations in: BRCA1, BRCA2, ATM, FANCA, PALB2, RAD51B, RAD51C) predicts response. This trial has now completed enrollment, and preliminary results will be presented at the American Society of Clinical Oncology 2016 Annual Meeting. Although final results are pending, the study does illustrate the feasibility of a large-scale metastatic tissue–based, biomarker-driven trial involving PARP inhibition in patients with metastatic CRPC. This study will also begin to ascertain the role of ETS fusions in determining response to PARP inhibitor therapy and will further explore the contribution of DRD to patient outcomes in those treated with standard therapy (abiraterone arm) and those treated with PARP inhibition (abiraterone plus veliparib arm).

Future studies

Given the data from the studies discussed previously and the enthusiasm for molecularly targeted trials in oncology, there is interest in further testing of PARP inhibition in prostate cancer patients. Multiple trials have recently been completed, are actively enrolling, or are nearing activation within this space (see Table,

Olaparib. Olaparib is the agent that is farthest along in clinical development and has an FDA indication in ovarian cancer. Olaparib also has the most active or pending studies in prostate cancer patients. TOPARP continues to enroll patients with metastatic CRPC, with a target accrual of 98 patients ( identifier: NCT01682772). There is a randomized double-blind, placebo-controlled phase II study of abiraterone plus olaparib or placebo for patients with metastatic CRPC who received prior docetaxel therapy ( identifier: NCT01972217). This trial, which is similar to the NCI 9012 study, has completed enrollment, but results are pending. Another trial is examining the biologic effect of olaparib on prostate cancer specimens when given alone or in combination with degarelix prior to prostatectomy ( identifier: NCT02324998). Furthermore, there is an open-label phase II study to assess the efficacy and safety of olaparib in patients with BRCA1 or BRCA2 mutations (regardless of tumor type), which is ongoing but no longer enrolling patients ( identifier: NCT01078662).

Veliparib. NCI 9012 (discussed previously) will help determine whether veliparib has potential therapeutic activity in metastatic CRPC and may identify molecularly determined subsets of disease (ie, ETS fusion–positive, DRD-positive) that might be expected to show the most benefit. The results of this study may help determine whether additional studies of this agent within the prostate cancer space are warranted.

Niraparib. The Hoosier Cancer Research Network has a planned phase I study of the combination of enzalutamide and niraparib for patients with metastatic CRPC ( identifier: NCT02500901), which has not yet begun enrollment. The primary endpoint of this study will be determination of MTD and dose-limiting toxicity.

Talazoparib. Although no prostate cancer–specific trials using other PARP inhibitors are currently active, several trials for molecularly targeted patient populations or phase I trials for toxicity assessment in combination with chemotherapy are ongoing; these provide some information on prostate cancer populations, depending on the types of solid tumors enrolled. There is a phase I trial of talazoparib in combination with carboplatin and paclitaxel ( identifier: NCT02317874) and another for patients with solid tumors and hepatic and renal dysfunction ( identifier: NCT02567396).

Precision Targeting of the PARP Pathway in Prostate Cancer

PARP inhibitors are a promising therapeutic option for men with prostate cancer. There is good evidence that men with either germline or somatic mutations in DNA repair pathways can derive therapeutic benefit from inhibition of PARP1/2, which blocks repair of SSB, driving persistent DSBs that lead to cancer cell lethality. Preclinical data also suggest that PARP inhibition may produce benefits by targeting chromatin and gene transcription, which implies that clinical benefits may extend beyond patients with DRD tumors.[12] To continue to develop PARP inhibitors within the prostate cancer field, we will need to develop and refine a set of biomarkers for use in selecting the right patient populations for these agents and then incorporate these biomarkers into prospective studies. As part of a precision therapy strategy, PARP inhibitors will likely play an important role in the management of prostate cancer in the near future.

It is now feasible to comprehensively profile the mutational, epigenetic, and gene expression changes in men with prostate cancer, and we are beginning to use this information to guide treatment choices.[7] Unfortunately, the functional relevance of many of the molecular features uncovered in these profiles is not completely understood. DNA repair processes are complex and require many genes for efficient repair of various types of DNA damage. Most past and ongoing studies focused on patients with specific molecular features, such as BRCA1, BRCA2, ATM, FANCA, PALB2, RAD51B, and RAD51C mutations. While mutations of these genes are likely to affect sensitivity to PARP inhibitors, mutations in other DNA repair or transcription factor genes may as well, and identification of those genes could expand the patient population that could benefit from therapy. Determination of whether other genes are susceptible to PARP inhibitor therapy will require robust preclinical models with a wide selection of genetic changes that reflect human disease; such models can be used to determine whether additional mutations and epigenetic or gene expression changes also result in PARP inhibitor sensitivity. Given the potential infrequency of many of the individual mutations that might sensitize to PARP inhibitors, large-scale registries that catalog mutations and their responsiveness to therapies may be needed.

As we define the molecular features that suggest sensitivity to PARP inhibition, the challenge will then become understanding the best strategy for incorporating these targeted agents into our standard treatment algorithms. In the context of prostate cancer, PARP inhibitors could be considered in high-risk patient populations in an adjuvant manner, before or with androgen deprivation therapy (ADT) in patients with newly metastatic disease, or in the setting of castration-resistant disease before or after the many other therapeutic options. To date, most trials in the prostate cancer space have been in the castration-resistant setting, perhaps because mutations in DNA damage genes may become more common as the disease progresses.[25] Nonetheless, there is no reason to assume that patients who harbor mutations may not benefit earlier in the disease course. Adjuvant use of PARP inhibitors in those with high-risk or micrometastatic disease could conceivably render patients disease free. Similarly, the combination of ADT and PARP inhibitors in early metastatic disease may provoke prolonged progression-free intervals similar to the situation with early docetaxel therapy but with less toxicity.[4,5] In the context of castration-resistant disease, it is reasonable to hypothesize that the combination of PARP inhibitors with hormonal agents such as abiraterone or enzalutamide or with chemotherapies might act synergistically to promote disease control.

The trials to examine these questions may be more challenging to design and execute because patients with sensitizing molecular changes represent a limited subset of total patients with prostate cancer. This means that in order to identify the subset that will benefit, many will need to be screened.[25] Because most molecular analyses are done using biopsy tissue, screening and cost may be challenging factors. In addition, the natural history of patients with DNA damage pathway mutations may also be distinct from those without such mutations. It is conceivable that mutations in DNA damage response genes may modulate patient response to standard hormonal agents, chemotherapy, or radium because all three of these therapeutic modalities have the potential to induce DNA damage in prostate cancer cells. Given these caveats, it will be essential to design an efficient precision medicine clinical trial pipeline that can rapidly molecularly profile patient tumors, assign to a therapeutic intervention, and then assess the complex resulting data and analyze results according to molecular categories.

PARP inhibitors have the potential to be a promising addition to the therapeutic arsenal used to treat prostate cancer and other solid tumors that harbor the appropriate molecular features. The transition from a standard, one-size-fits-all approach to a targeted, precision medicine strategy in which an individual prostate cancer patient’s tumor biology will guide choice of therapy will require careful planning and thought. The inclusion of PARP-targeted therapies before, after, with, or in place of standard hormonal therapies and chemotherapies will need to be defined so as to maximize antitumor effect and patient survival. Hopefully, application of these novel combinations in those most likely to benefit will ultimately lead to longer and better lives for patients with prostate cancer.

Financial Disclosure: Dr. Hussain is the principal investigator for a clinical trial of veliparib through the Cancer Therapy Evaluation Program (for AbbVie), and is collaborating on a clinical trial of olaparib for AstraZeneca.

David B. Solit, MD
Philip W. Kantoff, MD
Memorial Sloan Kettering Cancer Center, New York, New York

How an Ovarian Cancer Drug Came to Have ‘Breakthrough Therapy Designation’ for Prostate Cancer

With the emergence of precision medicine, clinicians can now take advantage of high-throughput tumor sequencing to identify driver mutations in individuals with cancer, with the goal of matching these with effective therapies. Since driver mutations can be shared across cancer types, precision medicine has also challenged the notion that cancer types, as defined by site of origin, are completely separate entities. One such example is the use of vemurafenib in multiple BRAF V600–mutant cancers. Another example is that of poly(adenosine diphosphate [ADP]–ribose) polymerase (PARP) inhibitors and prostate cancer. It is now recognized that DNA repair abnormalities, including and most notably BRCA2 mutations, are found frequently in the germline and as somatic mutations in the tumors in men with metastatic prostate cancer. Moreover, recent studies have demonstrated promising activity for olaparib—a drug approved for use in BRCA-mutated ovarian cancer—in men with castration-resistant disease and germline or somatic DNA repair abnormalities. This has led the US Food and Drug Administration to confer “breakthrough therapy designation” on olaparib, based on the strong belief that the drug will ultimately be approved for this indication.

What Questions Should Future Research on PARP Inhibitors for Prostate Cancer Focus on?

Many questions still remain unanswered. These include:

1) Given the pleiotropic effects of PARP inhibitors, which activities are the most critical and which PARP inhibitors are best for each disease/mutation scenario?

2) Have we identified the full gamut of DNA repair abnormalities that might respond to PARP inhibition?

3) Can we extend the spectrum of patients eligible for PARP inhibitors to those who are homologous recombination–proficient, by combining PARP inhibitors with therapies such as alkylating agents or antiangiogenic agents like cediranib?

4) Can we identify patients early on in their disease course in whom PARP inhibition may contribute to a curative strategy?


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Topoisomerase 1 & II inhibitors and cancer therapy

Larry H. Bernstein, MD, FCAP, Curator



Topoisomerase 1 & II Inhibitors and Cancer Therapy

Julia MoukharskayaClaire Verschraegen,

Hematology/Oncology Clinics of North America  June 2012; Volume 26, Issue 3:507–525     doi:10.1016/j.hoc.2012.03.002


Topoisomerase 1 inhibitors cure human cancer xenografts in animal models, more so than most other chemotherapy agents.

However, their activity in patients with cancer is modest.

Ongoing research is studying the optimal analogs that could reproduce animal data in the cancer population.

This article analyzes the clinical research with topoisomerase 1 inhibitors in ovarian cancer.

The first type I topoisomerase (Top1) inhibitors were found in the wood bark of Camptotheca acuminata, an oriental tree, the powder or injectable extracts of which have been used in traditional Chinese medicine.1 The class was named camptothecin (CPT) for the basic CPT compound (Fig. 1). Clinical studies of this group of drugs were initiated in the 1970s, and in the 1980s the Top1 enzyme was identified as the cellular target of CPT.2,3 Topoisomerases relax the DNA supercoiling and perform catalytic functions during replication and transcription.4 There are two classes of topoisomerases. Type I enzymes cleave one strand of DNA and type II cleave both strands. Six topoisomerase genes have been identified in mammalian somatic cells within these two classes. Type IA enzymes consist of Top3 a and Top3 b; type IB consist of Top1 and Top1mt (mitochondrial); and type IIA consist of Top2 a and Top2 b. CPT is an inhibitor of Top1. Top1 cleaves the DNA phosphodiester backbone, nicking one strand of the DNA duplex and forming a Top1-DNA reversible cleavage complex by covalent bonding of a tyrosine residue. Single-strand breaks induced by Top1 help untangle excessive DNA supercoils during DNA replication and transcription (Fig. 2).5,6 Top1 is essential for survival.


Catalytic topoisomerase II inhibitors in cancer therapy

AK Larsen, AE Escargueil (Pierre and Marie Curie University – Paris), A Skladanowski

Pharmacology & Therapeutics  Aug 2003; 99(2):167-181

The nuclear enzyme DNA topoisomerase II is a major target for antineoplastic agents. All topoisomerase II-directed agents are able to interfere with at least one step of the catalytic cycle. Agents able to stabilize the covalent DNA topoisomerase II complex (also known as the cleavable complex) are traditionally called topoisomerase II poisons, while agents acting on any of the other steps in the catalytic cycle are called catalytic inhibitors. Thus, catalytic topoisomerase II inhibitors are a heterogeneous group of compounds that might interfere with the binding between DNA and topoisomerase II (aclarubicin and suramin), stabilize noncovalent DNA topoisomerase II complexes (merbarone, ICRF-187, and structurally related bisdioxopiperazine derivatives), or inhibit ATP binding (novobiocin). Some, such as fostriecin, may also have alternative biological targets. Whereas topoisomerase II poisons are used solely for their antitumor activities, catalytic inhibitors are utilized for a variety of reasons, including their activity as antineoplastic agents (aclarubicin and MST-16), cardioprotectors (ICRF-187), or modulators in order to increase the efficacy of other agents (suramin and novobiocin). In this review, the mechanism and biological activity of different catalytic inhibitors is described, with emphasis on therapeutically used compounds. We will then discuss future development and applications of this interesting class of compounds.

Fig. 1. The catalytic cycle of DNA topoisomerase II. The ATPase domains of topoisomerase II are shown in light blue, the core domain in dark blue, and the active site tyrosine residue in red. The C-terminal domain of the enzyme is not included in the diagram since its orientation, with respect to the rest of the molecule, is not known. The catalytic cycle is initiated by enzyme binding to two double-stranded DNA segments called the G segment (in red) and the T segment (in green) (Step 1). Next, two ATP molecules are bound, which is associated with dimerization of the ATPase domains (Step 2). The G segment is cleaved (Step 3) and the T segment is transported through the break in the G segment, which is accompanied by the hydrolysis of one ATP molecule (Step 4). The G segment is then religated and the remaining ATP molecule is hydrolyzed (Step 5). Upon dissociation of the two ADP molecules, the T segment is transported through the opening in the C-terminal part of the enzyme (Step 6) followed by closing of this gate. Finally, the N-terminal ATPase domains reopen, allowing the enzyme to dissociate from DNA (Step 7). Data from Berger et al. (1996), Baird et al. (1999), Brino et al. (2000), and Hu et al. (2002).


Targeting HIF-1 for cancer therapy

Gregg L. Semenza

Nature Reviews Cancer 3, 721-732 (October 2003) |

Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes that are involved in crucial aspects of cancer biology, including angiogenesis, cell survival, glucose metabolism and invasion. Intratumoral hypoxia and genetic alterations can lead to HIF-1α overexpression, which has been associated with increased patient mortality in several cancer types. In preclinical studies, inhibition of HIF-1 activity has marked effects on tumour growth. Efforts are underway to identify inhibitors of HIF-1 and to test their efficacy as anticancer therapeutics.


Targeting DNA topoisomerase II in cancer chemotherapy

Recent molecular studies have greatly expanded the biological contexts where Top2 plays critical roles, including DNA replication, transcription and chromosome segregation. Although the biological functions of Top2 are important for insuring genomic integrity, the ability to interfere with Top2 and generate enzyme mediated DNA damage is an effective strategy for cancer chemotherapy. The molecular tools that have allowed understanding the biological functions of Top2 are also being applied to understanding the details of drug action. These studies promise a more refined ability to target Top2 as an effective anti-cancer strategy.

An important reason why Top2 has held the interest of researchers studying cancer was the discovery that active anti-cancer drugs, notably etoposide and doxorubicin target Top21. These studies showed that most clinically active drugs that target Top2 generate enzyme mediated DNA damage24. Since etoposide and doxorubicin are highly active anti-cancer agents in many different settings, an identification of a critical target of these drugs was a major landmark in the pharmacology of anti-cancer drugs.

Recent work has shown that there may be contexts where the level of Top2 protein predicts clinical activity (as well as many contexts where it does not). With the understanding of mechanisms of drug action and improved patient survival rates has come the appreciation that clinical treatment with drugs targeting Top2 can lead to the dire consequence of secondary malignancies. An important goal of present and future work is to maximize therapeutic efficacy of therapy using Top2 targeting agents while minimizing the risks of secondary malignancy and other toxicities. This review highlights recent work that is relevant to maximizing the potential of Top2 as an anti-cancer drug target.

Inhibition of Top2 activity by anti-cancer agents

Drugs targeting Top2 are divided into two broad classes. The first class, which includes most of the clinically active agents including etoposide, doxorubicin, and mitoxantrone, lead to increases in the levels of Top2:DNA covalent complexes. Because these agents generate a “lesion” that includes DNA strand breaks and protein covalently bound to DNA, these agents have been termed Top2 poisons. A second class of compounds inhibits Top2 catalytic activity, but do not generate increases in the levels of Top2 covalent complexes. This second class of agents is thought to kill cells through elimination of the essential enzymatic activity of Top2 and is therefore termed catalytic inhibitors (Fig. 1).

Figure 1   Mechanisms of inhibiting of Top2
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Mechanisms of inhibiting of Top2

Top2 can be inhibited at several different points in the enzyme reaction cycle, which can generate different biochemical and cellular consequences. One simple mode of inhibition is to inhibit a step early in the enzyme reaction cycle. For example, competitive inhibitors of ATP binding prevent strand passage, and do not generate enzyme mediated DNA damage. While agents such as novobiocin and coumermycin (not shown on the figure) inhibit both prokaryotic and eukaryotic Top2s, they are either less potent as well as relatively nonspecific (e.g., novobiocin) or are poorly taken up by mammalian cells (e.g., coumermycin). Similar effects would occur with inhibitors that prevent the binding of Top2 to DNA such as aclarubicin. Agents that prevent DNA cleavage by Top2, such as merbarone would also be expected to act as simple catalytic inhibitors. While merbarone clearly prevents DNA cleavage by Top2126, merbarone clearly affects other targets besides Top2. A second mode of inhibition is blocking the catalytic cycle after DNA is cleaved but prior to DNA religation. This mode of inhibition occurs for most currently used Top2 targeting agents including anthracyclines and epipodophyllotoxins, as well as for agents that target prokaryotic type II topoisomerases. These agents prevent enzyme turnover, and therefore greatly inhibit the enzyme catalytic activity, however, the clearest effect is the generation of high levels of Top2:DNA covalent complexes. Therefore, these inhibitors generate DNA damage, and interfere with many DNA metabolic events such as transcription and replication. Since agents of this class convert Top2 into an agent that induces cellular damage, they have been termed topoisomerase poisons. Top2 can be inhibited after strand passage is completed, but prior to ATP hydrolysis and dissociation of N-terminal dimerization. Bisdioxopiperazines such as dexrazoxane (ICRF-187) inhibit both ATP hydrolysis and maintain Top2 as a closed clamp 74. As is the case with Top2 poisons, bisdioxopiperazines inhibit Top2 catalytic activity mainly by blocking enzyme turnover. Although these agents are frequently termed catalytic inhibitors, they leave Top2 trapped on DNA, and may interfere with DNA metabolism in ways distinct from the inhibitors described in pathway (A). Nonetheless, since bisdioxopiperazines are relatively specific for Top2, they are the most commonly used catalytic inhibitors of Top2 in mammalian cells 143.

There are several lines of evidence indicating the importance of the distinction between Top2 poisons and Top2 catalytic inhibitors. Studies in yeast and mammalian cells demonstrated that resistance to Top2 poisons is recessive, i.e., presence of a drug resistant Top2 in the presence of a drug sensitive allele results in cells that are drug sensitive (reviewed in 5,6). The importance of enzyme mediated DNA damage is also demonstrated by observations that Top2 poisons rapidly elicit DNA damage responses such as ATM phosphorylation and activation of downstream damage responses79. Resistance to Top2 targeting drugs in mammalian cells is frequently associated with reduced expression of Top2 isoforms6, suggesting that resistance is mediated through a reduction in enzyme mediated DNA damage, rather than through enhancing available enzyme activity (where resistance would arise from increased expression of Top2 isoforms).

The generation of high levels of Top2 DNA covalent complexes has profound effects on cell physiology. Top2 poisons effectively block transcription and replication. DNA strand breaks are rapidly detected following treatment with Top2 poisons, and most of the strand breaks are protein linked, as expected10,11. Cells subsequently commit to apoptosis, in fact etoposide is a very commonly used agent to study apoptotic processes12.

The pattern of responses observed with catalytic inhibitors of Top2 differ from that observed with Top2 poisons, albeit with several important complications. Most catalytic inhibitors of Top2 are not specific for Top2 inhibition (see Box 1) with the exception of bisdioxopiperazines. While bisdioxopiperazines generate DNA damage responses following long exposure13, they do not produce a DNA damage response following short term exposure1417. Importantly, in cell culture experiments, catalytic inhibitors of Top2 antagonize the toxicity of Top2 poisons18, indicating that the agents act by separable mechanisms. An important and still unanswered question is whether Top2 inhibitors that are not poisons might be active anti-cancer agents. This issue is addressed in the concluding sections of this review.

Box 1. Many different classes of compounds target Topoisomerase II

Drugs targeting topoisomerase II fall into two categories, Top2 poisons and Top2 catalytic inhibitors. Many Top2 poisons have demonstrated anti-cancer activity. Top2 poisons can be further sub-divided into intercalating and non-intercalating poisons. The intercalators are chemically diverse, and include doxorubicin and other anthracyclines, mitoxantrone, mAMSA, and a variety of other compounds that are not currently in clinical use such as amonafide and ellipticine5. Other than their ability to intercalate in DNA, there is no obvious chemical similarity that could explain the ability of these compounds to trap Top2. Importantly, some compounds, such as oAMSA and ethidium bromide have little ability to poison Top2, suggesting that intercalation of a small molecule is insufficient to trap Top2 as a covalent complex on DNA1,110. Some of the intercalating Top2 targeting drugs, notably the anthracyclines, produce a variety of effects on cells, including many effects that are independent of their action against Top2. For example, doxorubicin is known to produce free radicals, to cause membrane damage, and to induce protein:DNA crosslinks. Whether Top2 is the most important target of anthracyclines remains a controversial issue, (reviewed in 111), although some of the results presented in the text support the hypothesis that Top2 is the most relevant target for both clinical response and cardiotoxicity. For alternate hypotheses, see 112114.

Several classes of compounds have been described that inhibit Top2 activity but do not increase DNA cleavage. Most prominent are the bisdioxopiperazines, which inhibit the enzyme ATPase activity non-competitively and trap Top2 as a closed clamp74,117,118. ICRF-187, a bisdioxopiperazine, is used as a cardioprotectant in some patients treated with anthracyclines. Other Top2 catalytic inhibitors include novobiocin119121, merbarone122, and the anthracycline aclarubicin123. All three compounds have significant targets besides Top2121,124,125; therefore these compounds have not been useful in assessing the feasibility of using catalytic inhibitors of Top2 as an anti-cancer therapy. Merbarone has attracted interest because it is the only agent that has been found to inhibit Top2 cleavage of DNA but not affect protein:DNA binding126. QAP1 is a newly described purine analog that was rationally designed to target the Top2 ATPase activity127. This compound may be particularly useful in assessing the effects of catalytic inhibition of Top2. Several other catalytic inhibitors have been described, however, their detailed mechanism of action has not been explored.

The future of Top2 as a drug target

Is there a need for new and different Top2 drugs? The first answer to this question is a resounding yes, since Top2 targeting is clearly successful in a wide variety of contexts. It is clear from broiad clinical experience that Top2 targeting drugs can be safely and effectively combined with many other agents. The Top2 targeting drugs in clinical use were identified not based on their activity against Top2, but mainly on empirical anti-tumor activity. Therefore, it would be expected that rational screening would lead to potent and specific Top2 poisons. It would be very desirable to know if greater potency and specificity would enhance clinical response.

At the time etoposide and doxorubicin were approved for use, we did not know of the existence of Top2β. The results reviewed in this article suggest that the targeting of Top2β leads to several undesirable consequences and little clear benefit. The negative effects of targeting Top2β include the induction of cardiotoxicity, and potentially a major role in secondary malignancies. On the other hand, there are potential benefits of targeting Top2β, especially the ability to kill non-proliferating cells. While targeting Top2β may contribute to toxicity, it may also be important for eliminating cancer cells that function as cancer stem cells.

An important question is whether isotype specific Top2 poisons can be identified, since the two enzymes share catalytic mechanisms, and a great deal of amino acid homology in their catalytic domains. It has been previously suggested that the intercalators mAMSA and mitoxantrone confer cytotoxicity mainly due to targeting Top2β106. More recently, a novel intercalator NK314 has been reported to be highly specific for Top2α107,108. Toyoda and colleagues also suggested that etoposide and doxorubicin generate greater cytotoxicity by targeting Top2α. Taken together, these results suggest that agents specific for Top2α may possible, and may be useful for having both greater anti-tumor activity, and reduced toxicitiy.

The search for improved Top2 targeting drugs will require further advances in both the biochemistry and structural biology of drug action. While the structures that have already been determined have provided important insights into the biochemistry of Top2, the only structure of Top2 bound to a drug that has been determined is the ATPase domain of Top2 bound to ICRF-187109. The grail for understanding the biochemistry of a drug like etoposide is the determination of a ternary complex between drug, protein, and DNA. Hopefully, the structures of the breakage/reunion domains of Top2α and Top2β, especially their DNA bound forms, will be solved soon.

An interesting question related to drug development is whether catalytic inhibitors of Top2 might be active anti-cancer agents. Much of the literature on the action of Top2 poisons implicitly assumes that they inhibit Top2 activity. Compared to many other enzyme inhibitors, any of the currently described Top2 targeting agents has relatively poor potency (for example, the Ki of etoposide for Top2 is in the 5-20 μM range, the Ki for ICRF-193 is in the 1-2 μM range). The availability of crystal structures provides the tools for addressing whether Top2 inhibition will be a valuable strategy (and will provide tools needed to answer many important biological questions).

The recent biological insights in transcription, replication and checkpoint control also offer ways to better understand drug action and resistance. Since cancer cells can clearly present with altered topoisomerase levels, whether by amplification or changes in gene regulation, these alterations provide an opportunity for enhanced therapeutic index. Finally, active anti-cancer therapy requires an understanding of how cancer cells ‘make a living’, and topoisomerases clearly are central to many of these core biological functions.

At a glance

  • Top2 is the target of several important classes of anti-cancer drugs, including the epipodophyllotoxin etoposide, and the anthracycline doxorubicin.
  • Most clinically active drugs that target Top2 kill cells by trapping an enzyme intermediate termed the covalent complex. Therefore, the principal action of Top2 targeting drugs currently used are to generate enzyme mediated DNA damage.
  • A recent structure of the breakage reunion domain of Top2 bound to DNA has been determined. This structure is likely to be of great use in understanding the protein determinants of the action of drugs targeting Top2. A drug:protein:DNA ternary complex would be extremely valuable, but has not yet been determined.
  • Top2 mediated DNA damage is repaired by multiple pathways. The DNA damage includes DNA strand breaks and proteins covalently bound to DNA. Repair of Top2 damage requires double strand break repair pathways, and other pathways specific for the removal of protein:DNA adducts.
  • Sensitivity to Top2 targeting drugs depends in part on levels of Top2 protein. Cells overexpressing Top2 are hypersensitive to Top2 poisons while cells expressing low levels of Top2 are relatively drug resistant. Top2α is frequently co-amplified with ERBB2. This can lead to some tumors with elevated levels of Top2α.
  • An important side effect of targeting Top2 with Top2 poisons are secondary malignancies arising from drug induced translocations. Top2β may be the Top2 isoform that is most responsible for secondary malignancies caused by Top2 targeting drugs.
  • Anthracycline use is limited by cardiotoxicity. Although the mechanism of the cardiotoxicity is poorly understood, recent results suggest that anthracyclines acting against Top2β may contribute significantly to cardiotoxicity. There may be considerable benefit to developing Top2 targeting drugs specific for the Top2α isoform.
  • Catalytic inhibition of Top2 may also be a useful anti-cancer strategy. New compounds are being developed to test this possibility.


Anticancer Chemotherapy – Topoisomerase Inhibitors Part 1 …

Early effects of topoisomerase I inhibition on RNA polymerase II along transcribed genes in human cells.

Khobta A, Ferri F, Lotito L, Montecucco A, Rossi R, Capranico G.

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RNA Polymerase II Regulates Topoisomerase 1 Activity to Favor Efficient Transcription.

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A Curated History of the Science Behind the Ovarian Cancer β-Blocker Trial

Curator: Stephen J. Williams, Ph.D.


This post is a follow-up on the two reports found in this Open Access Journal


in order to explain some of the background which went into the development of these reports.

A recent paper by Anil Sood’s group at MD Anderson in Journal of Cancer: Clinical impact of selective and nonselective beta-blockers on survival in patients with ovarian cancer describes a retrospective pathologic evaluation of ovaries from patients taking various beta blockers for currently approved indications.

The history of this finding is quite interesting and, as I remember in a talk given by Dr. Sood in mid-2000’s, a microarray conducted by his lab had showed overexpression of the β2-AR (β2 adrenergic receptor in ovarian cancer cells relative to normal epithelium. At the time it appeared an interesting result however most of the cancer (and ovarian cancer) field were concentrating on the tyrosine kinase signaling pathways as potential therapeutic targets, as much promising translational research in this area was in focus at the time. As a result of this finding and noticing that sustained β-adrenergic stimulation can promote ovarian cancer cell growth (Sood, 2006), Dr. Sood’s group have been studying the effects of β-adrenergic signaling om ovarian cancer. In addition it has been shown that propanalol can block VEGF signaling and norepinephrine increased MMP2 and MMP9 expression, an effect mediated by the β2-AR.

The above re-post of a Scoop-IT describes promising results of a clinical trial for use of selective beta blockers in ovarian cancer.   As to date, there have been many clinical trials initiated in ovarian cancer and most have not met with success for example the following posts:

Good and Bad News Reported for Ovarian Cancer Therapy

a follow-up curation on the problems encountered with the PARP-inhibitor olaparib

enough is enough: Treat ‘Each Patient as an Individual’

which contains an interview with Dr. Maurie Markman (Vice President, Patient Oncology Services, and National Director for Medical Oncology, Cancer Treatment Centers of America) and Dr. Kathy D. Miller, Indiana University School of Medicine) and discusses how each patient’s ovarian cancer is genetically unique and needs to be treated as such

Therefore the mainstay therapy is still carboplatin plus a taxane (Taxotere, Abraxane). The results of this clinical trial show a 5 month improvement in survival, which for a deadly disease like ovarian cancer is a significant improvement.

First below is a SUMMARY of the paper’s methodology and findings.


  • Four participating institutions collected retrospective patient data and pathology reports from 1425 patients diagnosed with epithelial ovarian cancer (EOC)
  • Medical records were evaluated for use of both selective and nonselective β-blockers
  • β-blockers were used for various indications however most common indication was treatment for hypertension (71% had used β1 selective blockers while rest of patients taking β blockers were given nonselective blockers for a host of other indications)
  • most patients had stage III/IV disease and in general older (median age 63 years)
  • The authors looked at overall survival (OS) however progression free survival PFS) was not calculated


  • Hypertension was associated with decreased survival (40.1 monts versus 47.4 months for normotensive patients)
  • Overall Survival for patients on any β blockers was 47.8 months versus 42.0 months for nonusers
  • Patients receiving nonselective β blockers has an OS of 94.9 months versus 38 months for EOC patients receiving β1-selective blockers
  • No effect of diabetes mellitus on survival

Authors Note on Limitations of Study:

  • Retrospective in nature
  • Lack of documentation of dosage, trade-name and duration of β-blocker use
  • Important to stratify patients on selectivity of β-blocker since Eskander et. al. found no difference of Progression Free Survival and non-selective β-blocker
  • Several β adrenergic receptor polymorphisms may exist and no downstream biomarker evaluated to determine effect on signaling; could it be a noncanonical effect?

The goal of this brief, added curation is to paint a historical picture, and highlight the scientific findings which led up to the rationale behind this clinical trial.

How the βeta Adrenergic Receptor (βAR) Became a Target for Ovarian Cancer


A. βAR and its signaling over-expressed in ovarian cancer

Role of mitogen-activated protein kinase/extracellular signal-regulated kinase cascade in gonadotropin-releasing hormone-induced growth inhibition of a human ovarian cancer cell line.

Kimura A, Ohmichi M, Kurachi H, Ikegami H, Hayakawa J, Tasaka K, Kanda Y, Nishio Y, Jikihara H, Matsuura N, Murata Y.

Cancer Res. 1999 Oct 15;59(20):5133-42.

Cyclic AMP induces integrin-mediated cell adhesion through Epac and Rap1 upon stimulation of the beta 2-adrenergic receptor.

Rangarajan S, Enserink JM, Kuiperij HB, de Rooij J, Price LS, Schwede F, Bos JL.

J Cell Biol. 2003 Feb 17;160(4):487-93. Epub 2003 Feb 10.

B. Mechanistic Link Between Chronic Stress From Excess Adrenergic Stimulation and Angiogenesis and Metastasis

Stress-related mediators stimulate vascular endothelial growth factor secretion by two ovarian cancer cell lines.

Lutgendorf SK, Cole S, Costanzo E, Bradley S, Coffin J, Jabbari S, Rainwater K, Ritchie JM, Yang M, Sood AK.

Clin Cancer Res. 2003 Oct 1;9(12):4514-21.PMID:

Norepinephrine up-regulates the expression of vascular endothelial growth factor, matrix metalloproteinase (MMP)-2, and MMP-9 in nasopharyngeal carcinoma tumor cells.

Yang EV, Sood AK, Chen M, Li Y, Eubank TD, Marsh CB, Jewell S, Flavahan NA, Morrison C, Yeh PE, Lemeshow S, Glaser R.

Cancer Res. 2006 Nov 1;66(21):10357-64.

VEGF is differentially regulated in multiple myeloma-derived cell lines by norepinephrine.

Yang EV, Donovan EL, Benson DM, Glaser R.

Brain Behav Immun. 2008 Mar;22(3):318-23. Epub 2007 Nov 5.

Chronic stress promotes tumor growth and angiogenesis in a mouse model of ovarian carcinoma.

Thaker PH, Han LY, Kamat AA, Arevalo JM, Takahashi R, Lu C, Jennings NB, Armaiz-Pena G, Bankson JA, Ravoori M, Merritt WM, Lin YG, Mangala LS, Kim TJ, Coleman RL, Landen CN, Li Y, Felix E, Sanguino AM, Newman RA, Lloyd M, Gershenson DM, Kundra V, Lopez-Berestein G, Lutgendorf SK, Cole SW, Sood AK.

Nat Med. 2006 Aug;12(8):939-44. Epub 2006 Jul 23.

Norepinephrine up-regulates the expression of vascular endothelial growth factor, matrix metalloproteinase (MMP)-2, and MMP-9 in nasopharyngeal carcinoma tumor cells.

Yang EV, Sood AK, Chen M, Li Y, Eubank TD, Marsh CB, Jewell S, Flavahan NA, Morrison C, Yeh PE, Lemeshow S, Glaser R.

Cancer Res. 2006 Nov 1;66(21):10357-64.

C. In Vivo Studies Confirm In Vitro Findings That Chronic Stress Via Adrenergic overstimulation Increases Ovarian Cancer Growth

Chronic stress promotes tumor growth and angiogenesis in a mouse model of ovarian carcinoma.

Thaker PH, Han LY, Kamat AA, Arevalo JM, Takahashi R, Lu C, Jennings NB, Armaiz-Pena G, Bankson JA, Ravoori M, Merritt WM, Lin YG, Mangala LS, Kim TJ, Coleman RL, Landen CN, Li Y, Felix E, Sanguino AM, Newman RA, Lloyd M, Gershenson DM, Kundra V, Lopez-Berestein G, Lutgendorf SK, Cole SW, Sood AK.

Nat Med. 2006 Aug;12(8):939-44. Epub 2006 Jul 23.

Stress hormone-mediated invasion of ovarian cancer cells.

Sood AK, Bhatty R, Kamat AA, Landen CN, Han L, Thaker PH, Li Y, Gershenson DM, Lutgendorf S, Cole SW.

Clin Cancer Res. 2006 Jan 15;12(2):369-75.

The neuroendocrine impact of chronic stress on cancer.

Thaker PH, Lutgendorf SK, Sood AK.

Cell Cycle. 2007 Feb 15;6(4):430-3. Epub 2007 Feb 9. Review.

Surgical stress promotes tumor growth in ovarian carcinoma.

Lee JW, Shahzad MM, Lin YG, Armaiz-Pena G, Mangala LS, Han HD, Kim HS, Nam EJ, Jennings NB, Halder J, Nick AM, Stone RL, Lu C, Lutgendorf SK, Cole SW, Lokshin AE, Sood AK.

Clin Cancer Res. 2009 Apr 15;15(8):2695-702. doi: 10.1158/1078-0432.CCR-08-2966. Epub 2009 Apr 7.

Sood group wanted to mimic the surgical stress after laparoscopic surgery to see if surgical stress would promote the growth of micrometasteses remaining after surgical tumor removal. Propranolol completely blocked the effects of surgical stress on tumor growth, indicating a critical role for beta-adrenergic receptor signaling in mediating the effects of surgical stress on tumor growth. In the HeyA8 and SKOV3ip1 models, surgery significantly increased microvessel density (CD31) and vascular endothelial growth factor expression, which were blocked by propranolol treatment. Tumor growth after surgery was decreased in a mouse null for βAR. Levels of cytokines G-CSF, IL-1a, IL-6, and IL-15were increased after surgery

Stress effects on FosB- and interleukin-8 (IL8)-driven ovarian cancer growth and metastasis J Biol Chem. 2010 Nov 12;285(46):35462-70. doi: 10.1074/jbc.M110.109579. Epub 2010 Sep 8.

Shahzad MM1, Arevalo JM, Armaiz-Pena GN, Lu C, Stone RL, Moreno-Smith M, Nishimura M, Lee JW, Jennings NB, Bottsford-Miller J, Vivas-Mejia P, Lutgendorf SK, Lopez-Berestein G, Bar-Eli M, Cole SW, Sood AK.

Free PMC Article


A growing number of studies indicate that chronic stress can accelerate tumor growth due to sustained sympathetic nervous system activation. Our recent findings suggest that chronic stress is associated with increased IL8 levels. Here, we examined the molecular and biological significance of IL8 in stress-induced tumor growth. Norepinephrine (NE) treatment of ovarian cancer cells resulted in a 250-300% increase in IL8 protein and 240-320% increase in its mRNA levels. Epinephrine treatment resulted in similar increases. Moreover, NE treatment resulted in a 3.5-4-fold increase in IL8 promoter activity. These effects were blocked by propranolol. Promoter deletion analyses suggested that AP1 transcription factors might mediate catecholamine-stimulated up-regulation of IL8. siRNA inhibition studies identified FosB as the pivotal component responsible for IL8 regulation by NE. In vivo chronic stress resulted in increased tumor growth (by 221 and 235%; p < 0.01) in orthotopic xenograft models involving SKOV3ip1 and HeyA8 ovarian carcinoma cells. This enhanced tumor growth was completely blocked by IL8 or FosB gene silencing using 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine nanoliposomes. IL8 and FosB silencing reduced microvessel density (based on CD31 staining) by 2.5- and 3.5-fold, respectively (p < 0.001). Our findings indicate that neurobehavioral stress leads to FosB-driven increases in IL8, which is associated with increased tumor growth and metastases. These findings may have implications for ovarian cancer management.

Dopamine blocks stress-mediated ovarian carcinoma growth.

Moreno-Smith M, Lu C, Shahzad MM, Pena GN, Allen JK, Stone RL, Mangala LS, Han HD, Kim HS, Farley D, Berestein GL, Cole SW, Lutgendorf SK, Sood AK.

Clin Cancer Res. 2011 Jun 1;17(11):3649-59. doi: 10.1158/1078-0432.CCR-10-2441. Epub 2011 Apr 29.

D. Additional mechanisms iincluding JAK/STAT modulation, prostaglandin synthesis, AKT, and Slug implicated in Stress (norepinephrine) induced increase in Ovarian Tumor Growth

Sustained adrenergic signaling leads to increased metastasis in ovarian cancer via increased PGE2 synthesis.

Nagaraja AS, Dorniak PL, Sadaoui NC, Kang Y, Lin T, Armaiz-Pena G, Wu SY, Rupaimoole R, Allen JK, Gharpure KM, Pradeep S, Zand B, Previs RA, Hansen JM, Ivan C, Rodriguez-Aguayo C, Yang P, Lopez-Berestein G, Lutgendorf SK, Cole SW, Sood AK.

Oncogene. 2015 Aug 10. doi: 10.1038/onc.2015.302. [Epub ahead of print]

The antihypertension drug doxazosin suppresses JAK/STATs phosphorylation and enhances the effects of IFN-α/γ-induced apoptosis.

Park MS, Kim BR, Kang S, Kim DY, Rho SB.

Genes Cancer. 2014 Nov;5(11-12):470-9.

hTERT mediates norepinephrine-induced Slug expression and ovarian cancer aggressiveness.

Choi MJ, Cho KH, Lee S, Bae YJ, Jeong KJ, Rha SY, Choi EJ, Park JH, Kim JM, Lee JS, Mills GB, Lee HY.

Oncogene. 2015 Jun;34(26):3402-12. doi: 10.1038/onc.2014.270. Epub 2014 Aug 25.

The antihypertension drug doxazosin inhibits tumor growth and angiogenesis by decreasing VEGFR-2/Akt/mTOR signaling and VEGF and HIF-1α expression.

Park MS, Kim BR, Dong SM, Lee SH, Kim DY, Rho SB.

Oncotarget. 2014 Jul 15;5(13):4935-44.

Meeting Abstracts on the Subject

From 2007 AACR Meeting

Neuroendocrine Modulation of Signal Transducer and Activator of Transcription-3 in Ovarian Cancer

  1. Requests for reprints:
    Anil K. Sood, Departments of Gynecologic Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, 1155 Herman Pressler, CPB6.3244, Unit 1362, Houston, TX 77230-1439. Phone: 713-745-5266; Fax: 713-792-7586; E-mail:


There is growing evidence that chronic stress and other behavioral conditions are associated with cancer pathogenesis and progression, but the mechanisms involved in this association are poorly understood. We examined the effects of two mediators of stress, norepinephrine and epinephrine, on the activation of signal transducer and activator of transcription-3 (STAT3), a transcription factor that contributes to many promalignant pathways. Exposure of ovarian cancer cell lines to increasing concentrations of norepinephrine or epinephrine showed that both independently increased levels of phosphorylated STAT3 in a dose-dependent fashion. Immunolocalization and ELISA of nuclear extracts confirmed increased nuclear STAT3 in response to norepinephrine. Activation of STAT3 was inhibited by blockade of the β1- and β2-adrenergic receptors with propranolol, and by blocking protein kinase A with KT5720, but not with the α receptor blockers prazosin (α1) and/or yohimbine (α2). Catecholamine-mediated STAT3 activation was not inhibited by pretreatment with an anti–interleukin 6 (IL-6) antibody or with small interfering RNA (siRNA)–mediated decrease in IL-6 or gp130. Regarding the effects of STAT3 activation, exposure to norepinephrine resulted in an increase in invasion and matrix metalloproteinase (MMP-2 and MMP-9) production. These effects were completely blocked by STAT3-targeting siRNA. In mice, treatment with liposome-incorporated siRNA directed against STAT3 significantly reduced isoproterenol-stimulated tumor growth. These studies show IL-6–independent activation of STAT3 by norepinephrine and epinephrine, proceeding through the β1/β2-adrenergic receptors and protein kinase A, resulting in increased matrix metalloproteinase production, invasion, and in vivo tumor growth, which can be ameliorated by the down-regulation of STAT3. [Cancer Res 2007;67(21):10389–96]

From 2009 AACR Meeting

Abstract #2506: Functional \#946;2 adrenergic receptors (ADRB2) on human ovarian tumors portend worse clinical outcome


Objective: Stress hormones such as catecholamines can augment tumor metastasis and angiogenesis; however, the prevalence and clinical significance of adrenergic receptors in human ovarian cancer is unknown and is the focus of the current study. Methods: After IRB approval, paraffin-embedded samples from 137 patients with invasive epithelial ovarian carcinoma were examined for \#946;1- and \#946;2-adrenergic receptor (ADRB1 and ADRB2, respectively) expression. Correlations with clinical outcomes were determined using parametric and non-parametric tests. Survival analyses were performed using the Kaplan-Meier method. Expression of ADRB1 and -2 was examined by quantitative RT-PCR in 15 freshly extracted human ovarian carcinoma cells. Human ovarian carcinoma cells then underwent time-variable adrenergic stimulation, and tumorigenic and angiogenic cytokine levels were examined by ELISA. Results: Sixty-six percent of the tumors had high expression of ADRB1; 80% of specimens highly expressed ADRB2. Univariate analyses demonstrated that high ADRB1 expression was associated with serous histology (p=0.03) and the presence of ascites (p=0.03), while high expression of ADRB2 was associated with advanced stage (p=0.008). Moreover, high ADRB2 expression was associated with the lower overall survival (2.2 vs. 6.5 years; p<0.001). In multivariate analysis, controlling for FIGO stage, grade, cytoreduction, age, and ADRB expression, only FIGO stage, cytoreduction status, age, and ADRB status retained statistical significance in predicting overall survival. In tumor cells freshly isolated from human ovarian cancers, 75% of samples had high expression of ADRB2 while most lacked ADRB1 compared to normal surface epithelium. Stimulation of the freshly isolated ADRB2-positive human ovarian cancer cells with norepinephrine resulted in increased levels of cAMP and increased angiogenic cytokines IL-6 and VEGF. Conclusions: ADRB2 are frequently found on human ovarian tumors and are strongly associated with poor clinical outcome. These findings support a direct mechanism by which stress hormones modulate ovarian cancer growth and metastasis as well as provide a basis for therapeutic targeting.

And from the 2015 AACR Meeting:

Abstract 3368: Sustained adrenergic signaling activates pro-inflammatory prostaglandin network in ovarian carcinoma

  1. Archana S. Nagaraja1,

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA


Purpose: Catecholamine mediated stress effects are known to induce production of various pro-inflammatory cytokines. However, the mechanism and functional effect of adrenergic signaling in driving inflammation via pro-inflammatory metabolites is currently unknown. Here we address the functional and biological consequences of adrenergic-induced Cox2/PGE2 axis activation in ovarian cancer metastasis.

Methods: We first analyzed global metabolic changes in tumors isolated from patients with known Center for Epidemiologic Studies Depression Scale (CES-D; depressive) scores and tumoral norepinephrine (NE) levels. Beta-adrenergic receptor (ADRB) positive cells (Skov3 and HeyA8) were used to study gene and protein levels of PTGS2 (cyclooxygenase2), PTGES (prostaglandin E synthase) and metabolite PGE2 in vitro and in vivo. To study tumor-specific effects on catecholamine-derived expression of PTGS2, we used a novel DOPC delivery system of PTGS2 siRNA.

Results: Our results revealed that levels of PGs were significantly increased in patients with high depressive scores (>16). PGE2 was upregulated by 2.38 fold when compared to the low CES-D scores. A similar trend was also observed with other pro-inflammatory eicosanoids, such as 6-keto prostaglandin F1 Alpha (2.03), prostaglandin A2 (1.39) and prostaglandin E1 (1.39). Exposure to NE resulted in increased PTGS2 and PTGES (prostaglandin E2 synthase) gene expression and protein levels in Skov3 and HeyA8. PGE2 ELISA confirmed that upon treatment with NE, PGE2 levels were increased in conditioned medium from Skov3 and HeyA8 cells. Treatment with a broad ADRB agonist (isoproterenol) or ADRB2 specific agonist (terbutaline) led to increases in expression of PTGS2 and PTGES as well as PGE2 levels in supernatant. Conversely, treatment with a broad antagonist (propranolol) or an ADRB2 specific antagonist (butoxamine) in the presence of NE abrogated gene expression changes of PTGS2 and PTGES. ChIP analysis showed enrichment of Nf-kB binding to the promoter region of PTGS2 and PTGES by 2.4 and 4.0 fold respectively when Skov3ip1 cells were treated with NE. Silencing PTGS2 resulted in significantly decreased migration (40%) and invasion (25%) of Skov3 cells in the presence of NE. Importantly, in the Skov3-ip1 restraint stress orthotopic model, silencing PTGS2 abrogated stress mediated effects and decreased tumor burden by 70% compared to control siRNA with restraint stress.

Conclusion Increased adrenergic stimulation results in a pro-inflammatory milieu mediated by prostaglandins that drives tumor progression and metastasis in ovarian cancer.

Citation Format: Archana S. Nagaraja, Piotr Dorniak, Nouara Sadaoui, Guillermo Armaiz-Pena, Behrouz Zand, Sherry Y. Wu, Julie K. Allen, Rajesha Rupaimoole, Cristian Rodriguez-Aguayo, Sunila Pradeep, Lin Tan, Rebecca A. Previs, Jean M. Hansen, Peiying Yang, Garbiel Lopez-Berestein, Susan K. Lutgendorf, Steve Cole, Anil K. Sood. Sustained adrenergic signaling activates pro-inflammatory prostaglandin network in ovarian carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3368. doi:10.1158/1538-7445.AM2015-3368

Other Article in This Open Access Journal on Ovarian Cancer Include

Beta-Blockers help in better survival in ovarian cancer

Ovarian Cancer Survival Increased 5 Months Overall With Beta Blockers – Study – The Speaker

Model mimicking clinical profile of patients with ovarian cancer @ Yale School of Medicine

Preclinical study identifies ‘master’ proto-oncogene that regulates stress-induced ovarian cancer metastasis | MD Anderson Cancer Center

Beta-Blockers help in better survival in ovarian cancer

Role of Primary Cilia in Ovarian Cancer

Dasatinib in Combination With Other Drugs for Advanced, Recurrent Ovarian Cancer


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New Generation of Platinated Compounds to Circumvent Resistance

Curator/Writer: Stephen J. Williams, Ph.D.

Resistance to chemotherapeutic drugs continues to be a major hurdle in the treatment of neoplastic disorders, irregardless if the drug is a member of the cytotoxic “older” drugs or the cytostatic “newer” personalized therapies like the tyrosine kinase inhibitors.  For the platinatum compounds such as cisplatin and carboplatin, which are mainstays in therapeutic regimens for ovarian and certain head and neck cancers, development of resistance is often regarded as the final blow, as new options for these diseases have been limited.

Although there are many mechanisms by which resistance to platinated compounds may develop the purpose of this posting is not to do an in-depth review of this area except to refer the reader to the book   Ovarian Cancer and just to summarize the well accepted mechanisms of cisplatin resistance including:

  • Decreased cellular cisplatin influx
  • Increased cellular cisplatin efflux
  • Increased cellular glutathione and subsequent conjugation, inactivation
  • Increased glutathione-S-transferase activity (GST) and subsequent inactivation, conjugation
  • Increased γ-GGT
  • Increased metallothionenes with subsequent conjugation, inactivation
  • Increased DNA repair: increased excision repair
  • DNA damage tolerance: loss of mismatch repair (MMR)
  • altered cell signaling activities and cell cycle protein expression

Williams, S.J., and Hamilton, T.C. Chemotherapeutic resistance in ovarian cancer. In: S.C. Rubin, and G.P. Sutton (eds.), Ovarian Cancer, pp.34-44. Lippincott, Wilkins, and Williams, New York, 2000.

Also for a great review on clinical platinum resistance by Drs. Maritn, Hamilton and Schilder please see the following Clinical Cancer Research link here.

This curation represents the scientific rationale for the development of a new class of platinated compounds which are meant to circumvent mechanisms of resistance, in this case the loss of mismatch repair (MMR) and increased tolerance to DNA damage.

An early step in the production of cytotoxicity by the important anticancer drug cisplatin and its analog carboplatin is the formation of intra- and inter-strand adducts with tumor cell DNA 1-3. This damage triggers a cascade of events, best characterized by activation of damage-sensing kinases (reviewed in 4), p53 stabilization, and induction of p53-related genes involved in apoptosis and cell cycle arrest, such as bax and the cyclin-dependent kinase inhibitor p21waf1/cip1/sdi1 (p21), respectively 5,6. DNA damage significantly induces p21 in various p53 wild-type tumor cell lines, including ovarian carcinoma cells, and this induction is responsible for the cell cycle arrest at G1/S and G2/M borders, allowing time for repair 7,8.  DNA lesions have the ability of  to result in an opening of chromatin structure, allowing for transcription factors to enter 56-58.  Therefore the anti-tumoral ability of cisplatin and other DNA damaging agents is correlated to their ability to bind to DNA and elicit responses, such as DNA breaks or DNA damage responses which ultimately lead to cell cycle arrest and apoptosis.  Therefore either repair of such lesions, the lack of recognition of such lesions, or the cellular tolerance of such lesions can lead to resistance of these agents.


Mechanisms of Cisplatin Sensitivity and Resistance. Red arrows show how a DNA lesion results in chemo-sensitivity while the beige arrow show common mechanisms of resistance including increased repair of the lesion, effects on expression patterns, and increased inactivation of the DNA damaging agent by conjugation reactions


















Increased DNA Repair Mechanisms of Platinated Lesion Lead to ChemoResistance



Description of Different Types of Cellular DNA Repair Pathways. Nucleotide Excision Repair is commonly up-regulated in highly cisplatin resistant cells












Loss of Mismatch Repair Can Lead to DNA Damage Tolerance

dnadamage tolerance









In the following Cancer Research paper Dr. Vaisman in the lab of Dr. Steve Chaney at North Carolina (and in collaboration with Dr. Tom Hamilton) describe how cisplatin resistance may arise from loss of mismatch repair and how oxaliplatin lesions are not recognized by the mismatch repair system.
Cancer Res. 1998 Aug 15;58(16):3579-85.

The role of hMLH1, hMSH3, and hMSH6 defects in cisplatin and oxaliplatin resistance: correlation with replicative bypass of platinum-DNA adducts.


Defects in mismatch repair are associated with cisplatin resistance, and several mechanisms have been proposed to explain this correlation. It is hypothesized that futile cycles of translesion synthesis past cisplatin-DNA adducts followed by removal of the newly synthesized DNA by an active mismatch repair system may lead to cell death. Thus, resistance to platinum-DNA adducts could arise through loss of the mismatch repair pathway. However, no direct link between mismatch repair status and replicative bypass ability has been reported. In this study, cytotoxicity and steady-state chain elongation assays indicate that hMLH1 or hMSH6 defects result in 1.5-4.8-fold increased cisplatin resistance and 2.5-6-fold increased replicative bypass of cisplatin adducts. Oxaliplatin adducts are not recognized by the mismatch repair complex, and no significant differences in bypass of oxaliplatin adducts in mismatch repair-proficient and -defective cells were found. Defects in hMSH3 did not alter sensitivity to, or replicative bypass of, either cisplatin or oxaliplatin adducts. These observations support the hypothesis that mismatch repair defects in hMutL alpha and hMutS alpha, but not in hMutS beta, contribute to increased net replicative bypass of cisplatin adducts and therefore to drug resistance by preventing futile cycles of translesion synthesis and mismatch correction.



The following are slides I had co-prepared with my mentor Dr. Thomas C. Hamilton, Ph.D. of Fox Chase Cancer Center on DNA Mismatch Repair, Oxaliplatin and Ovarina Cancer.








Multiple Platinum Analogs of Cisplatin (like Oxaliplatin )Had Been Designed to be Sensitive in MMR Deficient Tumors












































Please see below video on 2015 Nobel Laureates and their work to elucidate the celluar DNA repair mechanisms.

Clinical genetics expert Kenneth Offit gives an overview of Lynch syndrome, a genetic disorder that can cause colon (HNPCC) and other cancers by defects in the MSH2 DNA mismatch repair gene. (View Video)




  1. Johnson, S. W. et al. Relationship between platinum-DNA adduct formation, removal, and cytotoxicity in cisplatin sensitive and resistant human ovarian cancer cells. Cancer Res 54, 5911-5916 (1994).
  2. Eastman, A. The formation, isolation and characterization of DNA adducts produced by anticancer platinum complexes. Pharmacology and Therapeutics 34, 155-166 (1987).
  3. Zhen, W. et al. Increased gene-specific repair of cisplatin interstrand cross-links in cisplatin-resistant human ovarian cancer cell lines. Molecular and Cellular Biology 12, 3689-3698 (1992).
  4. Durocher, D. & Jackson, S. P. DNA-PK, ATM and ATR as sensors of DNA damage: variations on a theme? Curr Opin Cell Biol 13, 225-231 (2001).
  5. el-Deiry, W. S. p21/p53, cellular growth control and genomic integrity. Curr Top Microbiol Immunol 227, 121-37 (1998).
  6. Ewen, M. E. & Miller, S. J. p53 and translational control. Biochim Biophys Acta 1242, 181-4 (1996).
  7. Gartel, A. L., Serfas, M. S. & Tyner, A. L. p21–negative regulator of the cell cycle. Proc Soc Exp Biol Med 213, 138-49 (1996).
  8. Chang, B. D. et al. p21Waf1/Cip1/Sdi1-induced growth arrest is associated with depletion of mitosis-control proteins and leads to abnormal mitosis and endoreduplication in recovering cells. Oncogene 19, 2165-70 (2000).
  9. Davies, N. P., Hardman, L. C. & Murray, V. The effect of chromatin structure on cisplatin damage in intact human cells. Nucleic Acids Res 28, 2954-2958 (2000).
  10. Vichi, P. et al. Cisplatin- and UV-damaged DNA lure the basal transcription factor TFIID/TBP. Embo J 16, 7444-7456 (1997).
  11. Xiao, G. et al. A DNA damage signal is required for p53 to activate gadd45. Cancer Res 60, 1711-9 (2000).

Other articles in this Open Access Journal on ChemoResistance Include:

Cancer Stem Cells as a Mechanism of Resistance

An alternative approach to overcoming the apoptotic resistance of pancreatic cancer

Mutation D538G – a novel mechanism conferring acquired Endocrine Resistance causes a change in the Estrogen Receptor and Treatment of Breast Cancer with Tamoxifen

Can IntraTumoral Heterogeneity Be Thought of as a Mechanism of Resistance?

Nitric Oxide Mitigates Sensitivity of Melanoma Cells to Cisplatin

Heroes in Medical Research: Barnett Rosenberg and the Discovery of Cisplatin

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Bisphosphonates and Bone Metastasis [6.3.1]

Curator: Stephen J. Williams, Ph.D.

bisophosphonates chemical

General Structure of Bisphosphonates

One of the hallmarks of advanced cancer is the ability to metastasize (tumor cells migrating from primary tumor and colonize in a different anatomical site in the body) and many histologic types of primary tumors have the propensity to metastasize to the bone. One of the frequent complications occurring from bone metastasis is bone fractures and severe pain associated with these cancer-associated bone fractures. An additional problem is cancer-associated hypercalcemia, which may or may not be dependent on bone-metastasis. The main humoral factor associated with cancer-related hypercalcemia is parathyroid hormone–related protein, which is produced by many solid tumors (Paget’s disease). Parathyroid hormone–related protein increases calcium by activating parathyroid hormone receptors in tissue, which results in osteoclastic bone resorption; it also increases renal tubular resorption of calcium {see (1) Bower reference for more information). This curation involves three areas:

  1. The Changing Views How Bone Remodeling Occurs
  2. Early Development of Agents that Alter Bone Remodeling and Early Use in Cancer Patients
  3. Recent Developments Regarding Use of Bisphosphonates in Cancer Patients

As there are numerous articles (1360; more than to manually curate) on “bone”, “metastasis” and “bisphosphonates” the following link is to a Pubmed search on the terms

In addition there are subset searches to show use of bisphosphonates in common cancers and files given below with numbers of articles:

Search terms with Pubmed link # citations
bone metastasis bisphosphonates 1360
+ breast 559
+ prostate 349
+ colon 9
+ lung 222
  1. The Changing Views How Bone Remodeling Occurs

Bone remodeling (or bone metabolism) is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation). These processes also control the reshaping or replacement of bone following injuries like fractures but also micro-damage, which occurs during normal activity. Remodeling responds also to functional demands of the mechanical loading.

In the first year of life, almost 100% of the skeleton is replaced. In adults, remodeling proceeds at about 10% per year.[1]

An imbalance in the regulation of bone remodeling’s two sub-processes, bone resorption and bone formation, results in many metabolic bone diseases, such as osteoporosis. Two main types of cells are responsible for bone metabolism: osteoblasts (which secrete new bone), and osteoclasts (which break bone down). The structure of bones as well as adequate supply of calcium requires close cooperation between these two cell types and other cell populations present at the bone remodeling sites (ex. immune cells).[4] Bone metabolism relies on complex signaling pathways and control mechanisms to achieve proper rates of growth and differentiation. These controls include the action of several hormones, including parathyroid hormone (PTH), vitamin D, growth hormone, steroids, and calcitonin, as well as several bone marrow-derived membrane and soluble cytokines and growth factors (ex. M-CSF, RANKL, VEGF, IL-6 family…). It is in this way that the body is able to maintain proper levels of calcium required for physiological processes.

Subsequent to appropriate signaling, osteoclasts move to resorb the surface of the bone, followed by deposition of bone by osteoblasts. Together, the cells that are responsible for bone remodeling are known as the basic multicellular unit (BMU), and the temporal duration (i.e. lifespan) of the BMU is referred to as the bone remodeling period.

For a good review on bone remodeling please see Bone remodelling in a nutshell


bone remodeling 3

  1. Early Development of Agents that Alter Bone Remodeling and Early Use in Cancer Patients

Bisphosphonates had been first synthesized in the late 1800’s yet their development and approval for the indication of osteoporosis occurred over 100 years later, in the 1990’s. For a good review on the history of bisphosphonates please see the following review:

Historical perspectives on the clinical development of bisphosphonates in the treatment of bone diseases. Francis MD1, Valent DJ. J Musculoskelet Neuronal Interact. 2007 Jan-Mar;7(1):2-8.

For a good reference on bisphosphonates as a class, as well as indication, contraindication and side effects see University of Washington web page at


Please view slideshow in the following link: The Evolving Role of Bisphosphonates for Cancer Treatment-Induced Bone Loss presentation by Richard L. Theriault, DO, MBA at MD Anderson Cancer Center


  1. Recent Developments Regarding Use of Bisphosphonates in Cancer Patients

Bone Metastasis Treatment with Bisphosphonates; A review form OncoLink

Source: From University of Pennsylvania OncoLink® at

Julia Draznin Maltzman, MD and Modified by Lara Bonner Millar, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: December 18, 2014


Bone metastases are a common complication of advanced cancer. They are especially prevalent (up to 70%) in breast and prostate cancer. Bone metastases can cause severe pain, bone fractures, life-threatening electrolyte imbalances, and nerve compression syndromes. The pain and neurologic dysfunction may be difficult to treat and significantly compromises the patients’ quality of life. Bone metastases usually signify advanced, often incurable disease.

Osteolytic vs. osteoblastic

Bony metastases are characterized as being either osteolytic or osteoblastic. Osteolytic means that the tumor caused bone break down or dissolution. This usually results in loss of calcium from bone. On X-rays these are seen as holes called “lucencies” within the bone. Diffuse osteolytic lesions are most characteristic of a blood cancer called Multiple Myeloma, however they may be present in patients with many other types of cancer.

Osteoblastic bony lesions, by contrast, are characterized by increased bone production. The tumor somehow signals to the bone to overproduce bone cells and result in rigid, inflexible bone formation. The cancer that typically causes osteoblastic bony lesions is prostate cancer. Most cancers result in either osteolytic or osteoblastic bony changes, but some malignancies can lead to both. Breast cancer patients usually develop osteolytic lesions, although at least 15-20 percent can have osteoblastic pathology.

Why the bone?

The bone is a common site of metastasis for many solid tissue cancers including prostate, breast, lung, kidney, stomach, bladder, uterus, thyroid, colon and rectum. Researchers speculate that this may be due to the high blood flow to the bone and bone marrow. Once cancer cells gain access to the blood vessels, they can travel all over the body and usually go where there is the highest flow of blood. Furthermore, tumor cells themselves secrete adhesive molecules that can bind to the bone marrow and bone matrix. This molecular interaction can cause the tumor to signal for increased bone destruction and enhance tumor growth within the bone. A recent scientific discovery showed that the bone is actually a rich source of growth factors. These growth factors signal cells to divide, grow, and mature. As the cancer attacks the bone, these growth factors are released and serve to further stimulate the tumor cells to grow. This results in a self-generating growth loop.

What are the symptoms of bone metastasis?

It must be recognized that the symptoms of bone metastasis can mimic many other disease conditions. Most people with bony pain do not have bone metastasis. That being noted, the most common symptom of a metastasis to the bone is pain. Another common presentation is a bone fracture without any history of trauma. Fracture is more common in lytic metastases than blastic metastases.

Some people with more advanced disease may come to medical attention because of numbness and tingling sensation in their feet and legs. They may have bowel and bladder dysfunction – either losing continence to urine and/or stool, or severe constipation and urinary retention. Others may complain of leg weakness and difficulty moving their legs against gravity. This would imply that there is tumor impinging on the spinal cord and compromising the nerves. This is considered an emergency called spinal cord compression, and requires immediate medical attention. Another less common presentation of metastatic disease to the bone is high levels of calcium in the body. High calcium can make patients constipated, result in abdominal pain, and at very high levels, can lead to confusion and mental status changes.

Diagnosis of bone metastasis

Once a patient experiences any of the symptoms of bone metastasis, various tests can be done to find the true cause. In some cases bone metastasis can be detected before the symptoms arise. X-rays, bone scans, and MRIs are used to diagnose this complication of cancer. X-rays are especially helpful in finding osteolytic lesions. These often appear as “holes” or dark spots in the bone on the x-ray film. Unfortunately, bone metastases often do not show up on plain x-rays until they are quite advanced. By contrast, a bone scan can detect very early bone metastases. This test is done by injecting the patient with a small amount of radio-tracing material in the vein. Special x-rays are taken sometime after the injection. The radiotracer will preferentially go to the site of disease and will appear as a darker, denser, area on the film. Because this technique is so sensitive, sometimes infections, arthritis, and old fractures can appear as dark spots on the bone scan and may be difficult to differentiate from a true cancer. Bone scans are also used to follow patients with known bone metastasis. Sometimes CT scan images can show if a cancer has spread to the bone. An MRI is most useful when examining nerve roots suspected of being compressed by tumor or bone fragments due to tumor destruction. It is used most often in the setting of spinal cord compromise.

There are no real blood tests that are currently used to diagnose a bone metastasis. There are, however, a number of blood tests that a provider can obtain that may suggest the presence of bone lesions, but the diagnosis rests with the combination of radiographic evidence, clinical picture, and natural history of the malignancy. For example, elevated levels of calcium or an enzyme called alkaline phosphatase can be related to bone metastasis, but these lab tests alone are insufficient to prove their presence.


The best treatment for bony metastasis is the treatment of the primary cancer. Therapies may include chemotherapy, hormone therapy, radiation therapy, immunotherapy, or treatment with monoclonal antibodies. Pain is often treated with narcotics and other pain medications, such as non-steroidal anti-inflammatory agents. Physical therapy may be helpful and surgery may have an important role if the cancer resulted in a fracture of the bone.


Bisphosphonates are s category of medications that decrease pain from bone metastasis and may improve overall bone health. Bisphosphonates man-made versions of a naturally occurring compound called pyrophosphate that prevents bone breakdown. They are a class of medications widely used in the treatment and prevention of osteoporosis and certain other bone diseases (such as Paget’s Disease), as well as in the treatment of elevated blood calcium. These drugs suppress bone breakdown by cells called osteoclasts, and, can indirectly stimulate the bone forming cells called osteoblasts. It is for this reason, and for the fact that bisphosphonates are very effective in relieving bone pain associated with metastatic disease, that they have transitioned to the oncology arena. However, treatment of bone metastases is not curative. There is increasing evidence that bisphosphonates can prevent bony complications in some metastatic cancers and may even improve survival in some cancers. Most researchers agree that these drugs are more helpful in osteolytic lesions and less so in osteoblastic metastasis in terms of bone restoration and health, but the bisphosphonates are able to alleviate pain associated with both types of lesions. The appropriate time to start treatment is once a bone metastasis has been identified on imaging.

Bisphosphonates can be given either orally or intravenously. The latter is the preferred route of administration for many oncologists as it is given monthly as a short infusion and does not have the gastrointestinal side effects that the oral bisphosphonates have. There are currently two approved and commonly used IV bisphosphonates –Pamidronate disodium (Aredia, Novartis) and zolendronic acid (Zometa, Novartis). Their side effect profile is fairly mild and includes a flu-like reaction during the first 48 hours after the infusion, kidney impairment and osteonecrosis of the jaw with long term use. Patients with renal impairment may not be candidates for this therapy.

Bisphophonates may have some level of anti-tumor activity in breast cancer. A recent Phase III clinical trial revealed that the addition of Zometa to endocrine therapy, improves disease-free survival, but not overall survival, in pre-menopausal patients with estrogen-receptor postive early breast cancer. Another trial called AZURE found no effect from the bisphosphonate zolendronic acid (Zometa, Novartis) on the recurrence of breast cancer or on overall survival. However, several other studies on bisphosphonates and breast cancer are ongoing, and for now, their use is not recommended in patients without metastases.

In addition to bisphosphonates, osteoclast inhibition can also be achieved through other means. Another medication, Denosumab (XGEVA, Amgen), targets a receptor called receptor activator of nuclear factor kappa B ligand (RANKL), is able to block osteoclast formation. A few studies comparing Denosumab to bisphosphonates have found Denosumab results in a longer time to skeletal events, on the order of a few months, compared to bisphosphonates, however many experts believe that the evidence is not strong enough to support one class of drug over another. The most common side effects of Denosumab are fatigue or asthenia, hypophosphatemia, hypocalcemia and nausea. Patients receiving bisphosphonates or denosumab should also be taking calcium and vitamin D supplementation.

The future

Skeletal metastases remain one of the more debilitating problems for cancer patients. Research is ongoing to identify the molecular mechanisms that result in both osteolytic and osteoblastic bone lesions. Perhaps the use of proteomics and gene array data may permit us to identify some factors specific to the tumor or to the bony lesion itself that could be used as therapeutic targets to teat or even prevent this complication.

In summary

  •  there is well established evidence in preclinical models that bisphosphonates:reduce the total tumor burden in bone
  • it is unclear as to the mechanisms of this preclinical finding as bisphosphonates have been shown to directly have antitumor activity
  • as the review by Holen I1, Coleman “Bisphosphonates as treatment of bone metastases” (abstract given below) there is conflicting clinical evidence of this effect found in preclinical models

Accelerated bone loss is a common clinical feature of advanced breast cancer, and anti-resorptive bisphosphonates are the current standard therapy used to reduce the number and frequency of skeletal-related complications experienced by patients. Bisphosphonates are potent inhibitors of bone resorption, acting by inducing osteoclast apoptosis and thereby preventing the development of cancer-induced bone lesions. In clinical use bisphosphonates are mainly considered to be bone-specific agents, but anti-tumour effects have been reported in a number of in vitro and in vivo studies. By combining bisphosphonates with chemotherapy agents, growth and progression of breast cancer bone metastases can be virtually eliminated in model systems. Recent clinical trials have indicated that there may be additional benefits from bisphosphonate treatment, including positive effects on recurrence and survival when added to standard endocrine therapy. Whereas the ability of bisphosphonates to reduce cancer-induced bone disease is well established, their potential direct anti-tumour effect remain controversial. Ongoing clinical trials will establish whether bisphosphonates can inhibit the development of bone metastases in high-risk breast cancer patients. This review summarizes the main studies that have investigated the effects of bisphosphonates, alone and in combination with other anti-cancer agents, using in vivo model systems of breast cancer bone metastases. We also give an overview of the use of bisphosphonates in the treatment of breast cancer, including examples of key clinical trials. The potential side effects and future clinical applications of bisphosphonates will be outlined.


  1. Bower M, Cox S. Endocrine and metabolic complications of advanced cancer. In: Doyle D, Hanks G, Cherny NI, Calman K, editors. Oxford textbook of palliative medicine. 3rd ed. New York, NY: Oxford University Press; 2004. p. 688-90.

Henry DH, Costa L, Goldwasser F, et al. Randomized, double-blind study of denosumab versus zoledronic acid in the treatment of bone metastases in patients with advanced cancer (excluding breast and prostate cancer) or multiple myeloma. J Clin Oncol. 2011;29(9):1125-32.

Van Poznak CH, Temin S, Yee GC, et al. American Society of Clinical Oncology executive summary of the clinical practice guideline update on the role of bone-modifying agents in metastatic breast cancer. J Clin Oncol. 2011;29(9):1221-7.

West, H. Denosumab for prevention of skeletal-related events in patients with bone metastases from solid tumors: incremental benefit, debatable value. J Clin Oncol. 2011;29(9):1095-8.

Gnant M, Mlineritsch B, Schippinger W et al.: Endocrine therapy plus zoledronic acid in premenopausal breast cancer. N Engl J Med. 360(7),679–691 (2009).

Treatment Guidelines by Cancer Organizations

ASCO Issues Updated Guideline on the Role of Bone-Modifying Agents in the Prevention and Treatment of Bone Metastases in Patients with Metastatic Breast Cancer

For Immediate Release

February 22, 2011


Steven Benowitz

ALEXANDRIA, Va. – The American Society of Clinical Oncology (ASCO) today issued an update to its clinical practice guideline on the use of bone-modifying agents, in particular, osteoclast inhibitors, to prevent and treat skeletal complications from bone metastases in patients with metastatic breast cancer. The new guideline includes recommendations on the use of a new drug option, denosumab (Xgeva), and addresses osteonecrosis of the jaw, an uncommon condition that may occur in association with bone-modifying agents. The updated guideline also provides new recommendations on monitoring of patients who undergo treatment with bone-modifying agents and highlights priorities for future research on these drugs.

ASCO’s Bisphosphonates in Breast Cancer Panel conducted a systematic review of the medical literature to develop the new recommendations. The updated guideline, American Society of Clinical Oncology Clinical Practice Guideline Update on the Role of Bone-Modifying Agents in Metastatic Breast Cancer, was published online today in the Journal of Clinical Oncology.

The guideline recommends that patients with breast cancer who have evidence of bone metastases be given one of three agents – denosumab, pamidronate or zoledronic acid – approved by the U.S. Food and Drug Administration. It does not support use of any one drug over the others. These drugs are all considered osteoclast inhibitors, but they belong to different drug families: pamidronate and zoledronic acid are part of a class of drugs called bisphosphonates, while denosumab is a monoclonal antibody that targets receptor activator of nuclear factor-kappa beta ligand (RANKL).

The guideline also recommends against initiating bone-modifying agents in the absence of bone metastases outside of a clinical trial. It notes that an abnormal bone scan result alone, without confirmation by a radiograph, CT or MRI scan, is not sufficient evidence to support treatment with these drugs.

“The updated recommendations take into account recent progress in controlling potential bone damage in metastatic breast cancer,” said Catherine Van Poznak, MD, co-chair of the Bisphosphonates in Breast Cancer Panel and assistant professor of medicine at the University of Michigan. “We’ve established that a growing number of osteoclast inhibitors can have a positive effect and decrease of the risk of skeletal-related events in women with bone metastases. Because many factors – including medical and economic – must be considered when selecting a therapy for an individual, it’s good to have several effective choices.”

Bone is one of the most common sites to which breast cancer spreads. Bone metastases occur in approximately 70 percent of patients with metastatic disease. These metastases can cause bone cells (osteoclasts) to become overactive, which can result in excessive bone loss, disrupting the bone architecture and causing skeletal-related events (SREs), such as fracture, the need for surgery or radiation therapy to bone, spinal cord compression and hypercalcemia of malignancy.

This document updates guideline recommendations that were first issued in 2000 and revised in 2003, and focused on the use of bisphosphonates. The current guideline uses the more inclusive term, bone-modifying agents, to reflect a wider category of therapeutic agents such as monoclonal antibodies that use different mechanisms of action to prevent and treat damage from bone metastases. The guideline notes that research remains to be conducted to address several areas where questions remain.

“The guideline considers new data in a variety of areas, including studies showing that denosumab has equivalent effectiveness compared with other currently available drug therapies,” explained bisphosphonates panel co-chair Jamie Von Roenn, MD, professor of medicine at Northwestern University. “The guideline also provides guidance on preventing a rare, but significant complication of therapy with bone-modifying agents, osteonecrosis of the jaw.”

Denosumab is a human monoclonal antibody that targets a receptor, RANKL, involved in the regulation of bone remodeling. The guideline cites evidence from a randomized Phase III trial showing that denosumab appears to be comparable to zoledronic acid in reducing the risk of SREs in women with bone metastases from breast cancer. Denosumab is given subcutaneously, and can have side effects such as hypocalcemia.

The guideline also addresses the recently discovered osteonecrosis of the jaw. The first reports of this degenerative condition were published in the medical and dental literature in 2003. The committee recommended that all patients with breast cancer get dental evaluations and receive preventive dentistry care before beginning treatment with bone-modifying osteoclast inhibitors.

The panel updated its recommendations regarding the effects of bisphosphonates on kidney function, particularly for those taking either pamidronate or zoledronic acid, which have been associated with deteriorating kidney function. It said that clinicians should monitor serum creatinine clearance prior to each dose of pamidronate or zoledronic acid according to FDA-approved labeling.

The panel did not recommend using biochemical markers to monitor bone-modifying agent effectiveness and use outside of a clinical trial.

While many of the 2003 recommendations remain the same, the guideline notes several research directions to be addressed, including:

  • Duration of therapy with bone modifying agents, and the timing or intervals between delivery.
  • The development of a risk index for SREs, and better ways to stratify patient risk of SRE or risk of toxicity from a bone-modifying agent. Individual risk may guide selection of timing for use of a bone-modifying agent therapy.
  • Trials specifically examining whether stage IV breast cancer patients who do not have evidence of bone metastases would benefit from bone-modifying agents.
  • The role of biomarkers in treatment selection and monitoring drug effectiveness.
  • Understanding the optimal dosing of calcium and vitamin D supplementation in patients treated with bone-modifying agents.

The meta-analysis from the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) was published in Lancet and suggested that “Adjuvant bisphosphonates reduce the rate of breast cancer recurrence in the bone and improve breast cancer survival, but there is definite benefit only in women who were postmenopausal when treatment began”.


  • Of 18, 206 women in trials of 2-5 years of bisphosphonate3453 first recurrences, and 2106 subsequent deaths.
  • Overall, the reductions in recurrence (RR 0·94, 95% CI 0·87-1·01; 2p=0·08), distant recurrence (0·92, 0·85-0·99; 2p=0·03), and breast cancer mortality (0·91, 0·83-0·99; 2p=0·04) were of only borderline significance
  • Among premenopausal women, treatment had no apparent effect on any outcome, but among 11 767 postmenopausal women it produced highly significant reductions in recurrence (RR 0·86, 95% CI 0·78-0·94; 2p=0·002), distant recurrence (0·82, 0·74-0·92; 2p=0·0003), bone recurrence (0·72, 0·60-0·86; 2p=0·0002), and breast cancer mortality (0·82, 0·73-0·93; 2p=0·002). “This was iregardless of age or bisphosphonate type.

Lancet. 2015 Jul 23. pii: S0140-6736(15)60908-4. doi: 10.1016/S0140-6736(15)60908-4. Adjuvant bisphosphonate treatment in early breast cancer: meta-analyses of individual patient data from randomised trials.

Early Breast Cancer Trialists’ Collaborative Group (EBCTCG).

This Study was reported at the 36th Annual San Antonio Breast Cancer Symposium (SABCS): Abstract S4-07. Presented December 12, 2013 and Medscape Medical News journalist Kate Johnson covered the finding with author interviews in the following article:

Bisphosphonates: ‘New Addition’ to Breast Cancer Treatment?

Kate Johnson

December 13, 2013

Editors’ Recommendations

SAN ANTONIO — Adjuvant bisphosphonate treatment significantly improves breast cancer survival and reduces bone recurrence in postmenopausal women with early breast cancer, according to a meta-analysis reported here at the 36th Annual San Antonio Breast Cancer Symposium.

“We have finally defined a new addition to standard treatment,” announced lead investigator Robert Coleman, MD, professor of oncology at the University of Sheffield in the United Kingdom. He emphasized that, as hypothesized, the benefits of this therapy were confined to postmenopausal women.

“There is absolutely no effect on mortality in premenopausal women, with a hazard ratio [HR] of 1.0,” he reported. “But for postmenopausal women, we see a 17% reduction in the risk of death [HR, 0.83], which is highly statistically significant.”

In terms of the absolute benefit, bisphosphonates decreased the breast cancer mortality rate from 18.3% to 15.2% in postmenopausal women (P = .004).

The separation of benefit by menopausal status was also seen in the bone recurrence data.

In premenopausal women, there is no significant effect on bone recurrence (HR, 0.93), whereas in postmenopausal women, there was a 34% reduction. The difference was “highly significant,” said Dr. Coleman.

“I personally believe adjuvant bisphosphonates should be standard treatment in postmenopausal women with breast cancer,” said Michael Gnant, MD, professor of surgery at the Medical University of Vienna, who was one of the study investigators. He spoke during a plenary session before the results were formally announced. (Please click this LINK to See VIDEO Interview with Dr. Gnant)

“This is an important analysis,” said Rowan Chlebowski, MD, PhD, medical oncologist from the Harbor-UCLA Medical Center in Los Angeles.

“There will be a substantial increase in the use of bisphosphonates,” he told Medscape Medical News after the presentation.

“The only question is whether people will accept this analysis as the final word.” Dr. Chlebowski explained that some people might criticize the study as being a post hoc analysis of previous findings.

“You might find some mixed feelings about whether this should be accepted, but I think this will get people thinking,” he said. Dr. Chlebowski previously reported a large observational study that demonstrated that postmenopausal women taking oral bisphosphonates for osteoporosis had a significantly lower risk for breast cancer.

Bisphosphonates were originally indicated for the treatment of osteoporosis, and include agents such as alendronate (Fosamax, Merck), ibandronate (Boniva, Genentech), risedronate (Actonel, sanofi-aventis), and zoledronic acid (Reclast, Novartis). But they are also indicated for bone-related use in breast cancer patients, Dr. Chlebowski pointed out.

Because bisphosphonates “also have an indication for preventing bone loss associated with aromatase inhibitor use, they are already approved in this setting, and would prevent recurrences. It will be interesting to see if guideline panels” like these findings, he noted.

Why Postmenopausal Women Benefit

In the plenary session, Dr. Gnant acknowledged that the data on bisphosphonates to date have been mixed.

There are “many trials showing controversial results” for bisphosphonates in the context of breast cancer, he said. “When we put them all together in an unselected population, some show beneficial effects and some do not.”

Dr. Gnant explained why bisphosphonates appear to be effective in older but not younger women. “When you confine your analysis to the low-estrogen environment, postmenopausal women, or women rendered menopausal by ovarian function suppression, we see that all these trials show a consistent benefit for these patients,” he said.

“Essentially, this low-estrogen hypothesis as a prerequisite for adjuvant bisphosphonate activity means that we believe these treatments can silence the bone marrow microenvironment. However, this only translates to relevant clinical benefits in low-estrogen environments,” he added.

More Study Details

The meta-analysis involved 36 trials of adjuvant bisphosphonates in breast cancer with 17,791 pre- and postmenopausal women.

The primary outcomes of the study were time to distant recurrence, local recurrence, and new second primary breast cancer (ipsilateral or contralateral), time to first distant recurrence (ignoring any previous locoregional or contralateral recurrences), and breast cancer mortality.

Planned subgroup analyses based on hypotheses generated from previous findings included site of recurrence, site of first distant metastasis, menopausal status, and type and schedule of bisphosphonate therapy, said Dr. Coleman.

With bisphosphonate therapy, there was a nonsignificant 1% reduction in breast cancer recurrence at 10 years in postmenopausal women, compared with premenopausal women (25.4% vs 26.5%), and “a small borderline advantage” for distant recurrence (20.9% vs 22.3%), he reported.

However, there was a significant benefit of bisphosphonates in bone recurrence in postmenopausal women (6.9% vs 8.4%; P = .0009), with no effect on nonbone recurrence.

There was no impact of bisphosphonates on local recurrence or cancer in the contralateral breast.

For distant recurrence, there was a 3.5% absolute benefit in postmenopausal women (18.4% vs 21.9%; P = .0003); for distant recurrence, there is was a significant improvement of 2.9% in bone recurrence (5.9% vs 8.8%; P < .00001).

There was no significant reduction in first distant recurrence outside bone, and risk reductions were similar, irrespective of estrogen-receptor status, node status, or use or not of chemotherapy.

“Adjuvant bisphosphonates reduce bone metastases and improve survival in postmenopausal women,” concluded Dr. Coleman. “We have statistical security in this result, with a 34% reduction in the risk of bone recurrence (P = .00001), and a 17% — or 1 in 6 — reduction in the risk of breast cancer death (P =.004).”

The analysis struck a clear line between pre- and postmenopausal women — something that was revealed in a subgroup analysis the AZURE trial, which Dr. Coleman was involved in (N Engl J Med. 2011;365:1396-1405).

Because of this, he was asked about the validity of basing the current analysis on the AZURE hypothesis-generating population.

“We repeated the analysis without the AZURE patients, because they are the hypothesis-generating population, and the P values and risk reductions did not change,” he explained.

Source: Medscape Medical News at

Updated on 10/20/2015: Other articles for reference on Bisphosphonates and Metastasis

Clin Exp Metastasis. 2015 Oct;32(7):689-702. doi: 10.1007/s10585-015-9737-y. Epub 2015 Aug 1.

Human breast cancer bone metastasis in vitro and in vivo: a novel 3D model system for studies of tumour cell-bone cell interactions.

Author information

  • 1Academic Unit of Clinical Oncology, Department of Oncology, Mellanby Centre for Bone Research, Medical School, University of Sheffield, Sheffield, S10 2RX, UK.
  • 2Department of Human Metabolism, Mellanby Centre for Bone Research, Medical School, University of Sheffield, Sheffield, S10 2RX, UK.
  • 3Academic Unit of Clinical Oncology, Department of Oncology, Mellanby Centre for Bone Research, Medical School, University of Sheffield, Sheffield, S10 2RX, UK.


Bone is established as the preferred site of breast cancer metastasis. However, the precise mechanisms responsible for this preference remain unidentified. In order to improve outcome for patients with advanced breast cancer and skeletal involvement, we need to better understand how this process is initiated and regulated. As bone metastasis cannot be easily studied in patients, researchers have to date mainly relied on in vivo xenograft models. A major limitation of these is that they do not contain a human bone microenvironment, increasingly considered to be an important component of metastases. In order to address this shortcoming, we have developed a novel humanised bone model, where 1 × 10(5) luciferase-expressing MDA-MB-231 or T47D human breast tumour cells are seeded on viable human subchaodral bone discs in vitro. These discs contain functional osteoclasts 2-weeks after in vitro culture and positive staining for calcine 1-week after culture demonstrating active bone resorption/formation. In vitro inoculation of MDA-MB-231 or T47D cells colonised human bone cores and remained viable for <4 weeks, however, use of matrigel to enhance adhesion or a moving platform to increase diffusion of nutrients provided no additional advantage. Following colonisation by the tumour cells, bone discs pre-seeded with MDA-MB-231 cells were implanted subcutaneously into NOD SCID mice, and tumour growth monitored using in vivo imaging for up to 6 weeks. Tumour growth progressed in human bone discs in 80 % of the animals mimicking the later stages of human bone metastasis. Immunohistochemical and PCR analysis revealed that growing MDA-MB-231 cells in human bone resulted in these cells acquiring a molecular phenotype previously associated with breast cancer bone metastases. MDA-MB-231 cells grown in human bone discs showed increased expression of IL-1B, HRAS and MMP9 and decreased expression of S100A4, whereas, DKK2 and FN1 were unaltered compared with the same cells grown in mammary fat pads of mice not implanted with human bone discs.

Cancer. 2000 Jun 15;88(12 Suppl):2979-88.

Actions of bisphosphonate on bone metastasis in animal models of breast carcinoma.



Bone, which abundantly stores a variety of growth factors, provides a fertile soil for cancer cells to develop metastases by supplying these growth factors as a consequence of osteoclastic bone resorption. Accordingly, suppression of osteoclast activity is a primary approach to inhibit bone metastasis, and bisphosphonate (BP), a specific inhibitor of osteoclasts, has been widely used for the treatment of bone metastases in cancer patients. To obtain further insights into the therapeutic usefulness of BP, the authors studied the effects of BP on bone and visceral metastases in animal models of metastasis.


The authors used two animal models of breast carcinoma metastasis that they had developed in their laboratory over the last several years. One model uses female young nude mice in which inoculation of the MDA-MB-231 or MCF-7 human breast carcinoma cells into the left cardiac ventricle selectively develops osteolytic or osteosclerotic bone metastases, respectively. Another model uses syngeneic female mice (Balb/c) in which orthotopic inoculation of the 4T1 murine mammary carcinoma cells develops metastases in bone and visceral organs including lung, liver, and kidney.


BP inhibited the development and progression of osteolytic bone metastases of MDA-MB-231 breast carcinoma through increased apoptosis in osteoclasts and breast carcinoma cells colonized in bone. In a preventative administration, however, BP alone increased the metastases to visceral organs with profound inhibition of bone metastases. However, combination of BP with anticancer agents such as uracil and tegafur or doxorubicin suppressed the metastases not only in bone but also visceral organs and prolonged the survival in 4T1 mammary tumor-bearing animals. Of interest, inhibition of early osteolysis by BP inhibited the subsequent development of osteosclerotic bone metastases of MCF-7 breast carcinoma.


These results suggest that BP has beneficial effects on bone metastasis of breast carcinoma and is more effective when combined with anticancer agents. They also suggest that the animal models of bone metastasis described here allow us to design optimized regimen of BP administration for the treatment of breast carcinoma patients with bone and visceral metastases.

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Hormone Therapy [9.6]

Writer and Curator: Larry H. Bernstein, MD, FCAP

The structure of this article is as follows:

9.6.1 Hormone Treatment Fights Prostate Cancer

9.6.2 Diabetes and Cardiovascular Disease During Androgen Deprivation Therapy for Prostate Cancer

9.6.3 Breast Cancer and Hormone Therapy

9.6.4 Hormone Therapy and Different Ovarian Cancers

9.6.5 Chemotherapy versus hormonal treatment in platinum- and paclitaxel-refractory ovarian cancer: a randomised trial of the German Arbeitsgemeinschaft Gynaekologische Onkologie (AGO) Study Group Ovarian Cancer


9.6.1 Hormone Treatment Fights Prostate Cancer

By R. Morgan Griffin

Hormone therapy for prostate cancer has come a long way in the past few decades. Not so long ago, the only hormonal treatment for this disease was drastic: an orchiectomy, the surgical removal of the testicles.

Now we have a number of medications — available as pills, injections, and implants — that can give men the benefits of decreasing male hormone levels without irreversible surgery.

“I think hormonal therapy has done wonders for men with prostate cancer,” Stuart Holden, MD, Medical Director of the Prostate Cancer Foundation.

Hormone therapy for prostate cancer does have limitations. Right now, it’s usually used only in men whose cancer has recurred or spread elsewhere in the body.

But even in cases where removing or killing the cancer isn’t possible, hormone therapy can help slow down cancer growth. Though it isn’t a cure, hormone therapy for prostate cancer can help men with prostate cancer feel better and add years to their lives.

On average, hormone therapy can stop the advance of cancer for two to three years. However, it varies from case to case. Some men do well on hormone therapy for much longer.

The idea that hormones have an effect on prostate cancer is not new. The scientist Charles Huggins first established this over 60 years ago in work that led to his winning the Nobel Prize. Huggins found that removing one of the main sources of male hormones from the body — the testicles — could slow the growth of the disease.

“This procedure worked dramatically,” says Holden, who is also director of the Prostate Cancer Center at Cedar Sinai Medical Center in Los Angeles. “Before, these men were confined to bed and wracked with pain. Almost immediately afterwards, they improved.”

Huggins found that some types of prostate cancer cells androgens — to grow. Testosterone is one kind of androgen. About 90% to 95% of all androgens are made in the testicles, while the rest are made in the adrenal glands.

Hormone therapy for prostate cancer works by either preventing the body from making these androgens or by blocking their effects. Either way, the hormone levels drop, and the cancer’s growth slows.

In 85% to 90% of cases of advanced prostate cancer, hormone therapy can shrink the tumor.

However, hormone therapy for prostate cancer doesn’t work forever. The problem is that not all cancer cells need hormones to grow. Over time, these cells that aren’t reliant on hormones will spread. If this happens, hormone therapy won’t help anymore, and your doctor will need to shift to a different treatment approach.

There are two basic kinds of hormone therapy for prostate cancer. One class of drugs stops the body from making certain hormones. The other allows the body to make these hormones, but prevents them from attaching to the cancer cells. Some doctors start treatment with both drugs in an effort to achieve a total androgen block. This approach goes by several names: combined androgen blockade, complete androgen blockade, or total androgen blockade.

Here’s a rundown of the techniques.

  • Luteinizing hormone-releasing hormone agonists (LHRH agonists.)These are chemicals that stop the production of testosterone in the testicles. Essentially, they provide the benefits of an orchiectomy for men with advanced prostate cancer without surgery. This approach is sometimes called “chemical castration.” However, the effects are fully reversible if you stop taking the medication.Most LHRH agonists are injected every one to four months. Some examples are Lupron, Trelstar, Vantas, and Zoladex. A new drug, Viadur, is an implant placed in the arm just once a year.

    Side effects can be significant. They include: loss of sex drivehot flashes, development of breasts (gynecomastia) or painful breasts, loss of muscle, weight gain, fatigue, and decrease in levels of “good”cholesterol.

    Plenaxis is a drug that’s similar to LHRH agonists. However, because it can cause serious allergic reactions, it’s not used that often.

  • Anti-androgens. LHRH agonists and orchiectomies only affect the androgens that are made in the testicles. Thus they have no effect on the 5% to 10% of a man’s “male” hormones that are made in the adrenal glands. Anti-androgens are designed to affect the hormones made in the adrenal glands. They don’t stop the hormones from being made, but they stop them from having an effect on the cancer cells.The advantage of anti-androgens is that they have fewer side effects than LHRH agonists. Many men prefer them because they are less likely to diminish libido. Side effects include tenderness of the breasts, diarrhea, and nausea. These drugs are also taken as pills each day, which may be more convenient than injections. Examples are CasodexEulexin, and Nilandron.

    In some cases, starting treatment with an LHRH agonist can cause a “tumor flare,” a temporary acceleration of the cancer’s growth due to an initial increase in testosterone before the levels drop. This may cause the prostate gland to enlarge, obstructing the bladder and making it difficult to urinate. It’s believed that starting with an anti-androgen drug and then switching to an LHRH agonist can help avoid this problem. In patients with bone metastases, this “flare” can lead to significant complications such as bone pain, fractures, and nerve compression.

    Strangely, if treatment with an anti-androgen doesn’t work, stopping it may actually improve symptoms for a short time. This phenomenon is called “androgen withdrawal,” and experts aren’t sure why it happens.

  • Combined Androgen Blockade. This approach combines anti-androgens with LHRH agonists or an orchiectomy. By using both approaches, you can cut off or block the effects of hormones made by both the adrenal glands and the testicles. However, using both treatments can also increase the side effects. An orchiectomy or an LHRH agonist on its own can cause significant side effects like a loss of libido, impotence, and hot flashes. Adding an anti-androgen can cause diarrhea, and less often, nauseafatigue, and liver problems.
  • Estrogens. Some synthetic versions of female hormones are used for prostate cancer. In fact, they were one of the early treatments used for the disease. However, because of their serious cardiovascular side effects, they’re not used as often anymore. J. Brantley Thrasher, MD, a spokesman for the American Urological Association and chairman of urology at the University of Kansas Medical Center, says they’re usually used only after initial hormone treatments have failed. Examples of estrogens are DES (diethylstilbestrol), Premarin, and Estradiol.
  • Other Drugs. Proscar (finasteride) is another drug that indirectly blocks an androgen that helps prostate cancer cells grow. Depending

on the case, doctors sometimes use other anticancer drugs like Nizoral (ketoconazole) and Cytadren (aminoglutethimide.)

  • Orchiectomy. The surgical removal of the testicles was the earliest form of hormone therapy for prostate cancer. However, the procedure is permanent. As with LHRH agonists, side effects can be significant. They include: Loss of sex drive, hot flashes, development of breasts (gynecomastia) or painful breasts, loss of muscle, weight gain, fatigue, and decrease in levels of “good” cholesterol.

Hormone therapy for prostate cancer can cause osteoporosis, which can lead to broken bones. However, treatment with bisphosphonates — like ArediaFosamax, and Zometa — may help prevent this condition from developing.

Hormone (androgen deprivation) therapy for prostate cancer

Hormone therapy is also called androgen deprivation therapy (ADT) or androgen suppression therapy. The goal is to reduce levels of male hormones, called androgens, in the body, or to stop them from affecting prostate cancer cells.

The main androgens are testosterone and dihydrotestosterone (DHT). Most of the body’s androgens come from the testicles, but the adrenal glands also make a small amount. Androgens stimulate prostate cancer cells to grow. Lowering androgen levels or stopping them from getting into prostate cancer cells often makes prostate cancers shrink or grow more slowly for a time. But hormone therapy alone does not cure prostate cancer.

Hormone therapy may be used:

  • If the cancer has spread too far to be cured by surgery or radiation, or if you can’t have these treatments for some other reason
  • If your cancer remains or comes back after treatment with surgery or radiation therapy
  • Along with radiation therapy as initial treatment if you are at higher risk of the cancer coming back after treatment (based on a high Gleason score, high PSA level, and/or growth of the cancer outside the prostate)
  • Before radiation to try to shrink the cancer to make treatment more effective

Several types of hormone therapy can be used to treat prostate cancer. Some lower the levels of testosterone or other androgens (male hormones). Others block the action of those hormones.

Luteinizing hormone-releasing hormone (LHRH) analogs

These drugs lower the amount of testosterone made by the testicles. Treatment with these drugs is sometimes calledchemical castration or medical castration because they lower androgen levels just as well as orchiectomy.

Even though LHRH analogs (also called LHRH agonists or GnRH agonists) cost more than orchiectomy and require more frequent doctor visits, most men choose this method. These drugs allow the testicles to remain in place, but the testicles will shrink over time, and they may even become too small to feel.

LHRH analogs are injected or placed as small implants under the skin. Depending on the drug used, they are given anywhere from once a month up to once a year. The LHRH analogs available in the United States include leuprolide (Lupron®, Eligard®), goserelin (Zoladex®), triptorelin (Trelstar®), and histrelin (Vantas®).

When LHRH analogs are first given, testosterone levels go up briefly before falling to very low levels. This effect is called flare and results from the complex way in which LHRH analogs work. Men whose cancer has spread to the bones may have bone pain. If the cancer has spread to the spine, even a short-term increase in tumor growth as a result of the flare could compress the spinal cord and cause pain or paralysis. Flare can be avoided by giving drugs called anti-androgens for a few weeks when starting treatment with LHRH analogs. (Anti-androgens are discussed further on.)

Degarelix (Firmagon®)

Degarelix is an LHRH antagonist. LHRH antagonists work like LHRH agonists, but they reduce testosterone levels more quickly and do not cause tumor flare like the LHRH agonists do.

This drug is used to treat advanced prostate cancer. It is given as a monthly injection under the skin. The most common side effects are problems at the injection site (pain, redness, and swelling) and increased levels of liver enzymes on lab tests. Other side effects are discussed in detail below.

Abiraterone (Zytiga®)

Drugs such as LHRH agonists can stop the testicles from making androgens, but other cells in the body, including prostate cancer cells themselves, can still make small amounts, which can fuel cancer growth. Abiraterone blocks an enzyme called CYP17, which helps stop these cells from making androgens.

Abiraterone can be used in men with advanced castrate-resistant prostate cancer (cancer that is still growing despite low testosterone levels from an LHRH agonist, LHRH antagonist, or orchiectomy). Abiraterone has been shown to shrink or slow the growth of some of these tumors and help some of these men live longer.

This drug is taken as pills every day. This drug doesn’t stop the testicles from making testosterone, so men who haven’t had an orchiectomy need to continue treatment with an LHRH agonist or antagonist. Because abiraterone also lowers the level of some other hormones in the body, prednisone (a cortisone-like drug) needs to be taken during treatment as well to avoid certain side effects.

Drugs that stop androgens from working


Androgens have to bind to a protein in the cell called an androgen receptor to work. Anti-androgens are drugs that bind to these receptors so the androgens can’t.

Drugs of this type, such as flutamide (Eulexin®), bicalutamide (Casodex®), and nilutamide (Nilandron®), are pills taken daily.

Anti-androgens are not often used by themselves in the United States. An anti-androgen may be added to treatment if orchiectomy, an LHRH analog, or LHRH antagonist is no longer working by itself. An anti-androgen is also sometimes given for a few weeks when an LHRH analog is first started to prevent a tumor flare.

Anti-androgen treatment can be combined with orchiectomy or an LHRH analog as first-line hormone therapy. This is called combined androgen blockade (CAB).

9.6.2 Diabetes and Cardiovascular Disease During Androgen Deprivation Therapy for Prostate Cancer

Nancy L. KeatingA. James O’Malley and Matthew R. Smith
JCO Sep 20, 2006; 24(27):4448-4456

Purpose Androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) agonist is associated with increased fat mass and insulin resistance in men with prostate cancer, but the risk of obesity-related disease during treatment has not been well studied. We assessed whether androgen deprivation therapy is associated with an increased incidence of diabetes and cardiovascular disease. Patients and Methods Observational study of a population-based cohort of 73,196 fee-for-service Medicare enrollees age 66 years or older who were diagnosed with locoregional prostate cancer during 1992 to 1999 and observed through 2001. We used Cox proportional hazards models to assess whether treatment with GnRH agonists or orchiectomy was associated with diabetes, coronary heart disease, myocardial infarction, and sudden cardiac death. Results More than one third of men received a GnRH agonist during follow-up. GnRH agonist use was associated with increased risk of incident diabetes (adjusted hazard ratio [HR], 1.44; P < .001), coronary heart disease (adjusted HR, 1.16; P < .001), myocardial infarction (adjusted HR, 1.11; P = .03), and sudden cardiac death (adjusted HR, 1.16; P = .004). Men treated with orchiectomy were more likely to develop diabetes (adjusted HR, 1.34; P < .001) but not coronary heart disease, myocardial infarction, or sudden cardiac death (all P > .20). Conclusion GnRH agonist treatment for men with locoregional prostate cancer may be associated with an increased risk of incident diabetes and cardiovascular disease.

9.6.3 Breast Cancer and Hormone Therapy

There are certain hormones that can attach to breast cancer cells and affect their ability to multiply. The purpose of hormone therapy, also called endocrine therapy, is to add, block, or remove hormones.

With breast cancer, the female hormones estrogen andprogesterone can promote the growth of some breast cancer cells. Therefore in some patients, hormone therapy is given to block the body’s naturally occurring estrogen to slow or stop the cancer‘s growth.

There are two types of hormone therapy for breast cancer.

  • Drugs that inhibit estrogen and progesterone from promotingbreast cancer cell growth.
  • Drugs or surgery to turn off the production of hormones from the ovaries.

Faslodex, a estrogen receptor antagonist, binds to estrogen receptors and blocks their effects on cancer cells. Given as an injection, the drug is for HER2-positive metastatic disease in postmenopausal women who have already tried anti-estrogen therapy. Common side effects of Faslodex include:

  • Injection site pain
  • Nausea and vomiting
  • Loss of appetite
  • Weakness, fatigue
  • Hot flashes
  • Cough
  • Muscle, joint, and bone pain
  • Constipation
  • Shortness of breath

Zoladex and Lupron for Breast Cancer

Zoladex and Lupron are drugs that stop the production of estrogen by the ovaries. They are used in premenopausal women for the treatment of estrogen sensitive breast cancer.

Side effects of Zoladex and Lupron include:

  • Fluid retention
  • Hot flashes
  • Irregular menstrual periods
  • Pain at the injection site

Hormone-sensitive breast cancer cells contain proteins known as hormone receptors that become activated when hormones bind to them. The activated receptors cause changes in the expression of specific genes, which can lead to the stimulation of cell growth.

To determine whether breast cancer cells contain hormone receptors, doctors test samples of tumor tissue that have been removed by surgery. If the tumor cells contain estrogen receptors, the cancer is called estrogen receptor-positive (ER-positive), estrogen-sensitive, or estrogen-responsive. Similarly, if the tumor cells contain progesterone receptors, the cancer is called progesterone receptor-positive (PR- or PgR-positive). Approximately 70 percent of breast cancers are ER-positive. Most ER-positive breast cancers are also PR-positive (1).

Breast cancers that lack estrogen receptors are called estrogen receptor-negative (ER-negative). These tumors are estrogen-insensitive, meaning that they do not use estrogen to grow. Breast tumors that lack progesterone receptors are called progesterone receptor-negative (PR- or PgR-negative).

Hormone therapy (also called hormonal therapy, hormone treatment, or endocrine therapy) slows or stops the growth of hormone-sensitive tumors by blocking the body’s ability to produce hormones or by interfering with hormone action. Tumors that are hormone-insensitive do not respond to hormone therapy.

Hormone therapy for breast cancer is not the same as menopausal hormone therapy or female hormone replacement therapy, in which hormones are given to reduce the symptoms of menopause.

Several strategies have been developed to treat hormone-sensitive breast cancer, including the following:

Blocking ovarian function: Because the ovaries are the main source of estrogen in premenopausal women, estrogen levels in these women can be reduced by eliminating or suppressing ovarian function. Blocking ovarian function is called ovarian ablation.

Ovarian ablation can be done surgically in an operation to remove the ovaries (called oophorectomy) or by treatment with radiation. This type of ovarian ablation is usually permanent.

Alternatively, ovarian function can be suppressed temporarily by treatment with drugs called gonadotropin-releasing hormone (GnRH) agonists, which are also known as luteinizing hormone-releasing hormone (LH-RH) agonists. These medicines interfere with signals from the pituitary gland that stimulate the ovaries to produce estrogen.

Examples of ovarian suppression drugs that have been approved by the U.S. Food and Drug Administration (FDA) are goserelin (Zoladex®) and leuprolide (Lupron®).

Blocking estrogen production: Drugs called aromatase inhibitors can be used to block the activity of an enzyme called aromatase, which the body uses to make estrogen in the ovaries and in other tissues. Aromatase inhibitors are used primarily in postmenopausal women because the ovaries in premenopausal women produce too much aromatase for the inhibitors to block effectively. However, these drugs can be used in premenopausal women if they are given together with a drug that suppresses ovarian function.

Examples of aromatase inhibitors approved by the FDA are anastrozole (Arimidex®) and letrozole (Femara®), both of which temporarily inactivate aromatase, and exemestane (Aromasin®), which permanently inactivates the enzyme.

Blocking estrogen’s effects: Several types of drugs interfere with estrogen’s ability to stimulate the growth of breast cancer cells:

  • Selective estrogen receptor modulators (SERMs) bind to estrogen receptors, preventing estrogen from binding. Examples of SERMs approved by the FDA are tamoxifen (Nolvadex®), raloxifene (Evista®), andtoremifene (Fareston®). Tamoxifen has been used for more than 30 years to treat hormone receptor-positive breast cancer.Because SERMs bind to estrogen receptors, they can potentially not only block estrogen activity (i.e., serve as estrogen antagonists) but also mimic estrogen effects (i.e., serve as estrogen agonists). Most SERMs behave as estrogen antagonists in some tissues and as estrogen agonists in other tissues. For example, tamoxifen blocks the effects of estrogen in breast tissue but acts like estrogen in the uterus and bone.
  • Other antiestrogen drugs, such as fulvestrant (Faslodex®), work in a somewhat different way to block estrogen’s effects. Like SERMs, fulvestrant attaches to the estrogen receptor and functions as an estrogen antagonist. However, unlike SERMs, fulvestrant has no estrogen agonist effects. It is a pure antiestrogen. In addition, when fulvestrant binds to the estrogen receptor, the receptor is targeted for destruction.

There are three main ways that hormone therapy is used to treat hormone-sensitive breast cancer:

Adjuvant therapy for early-stage breast cancer: Research has shown that women treated for early-stage ER-positive breast cancer benefit from receiving at least 5 years of adjuvant hormone therapy (2). Adjuvant therapy is treatment given after the main treatment (surgery, in the case of early-stage breast cancer) to increase the likelihood of a cure.

Adjuvant therapy may include radiation therapy and some combination of chemotherapy, hormone therapy, and targeted therapyTamoxifen has been approved by the FDA for adjuvant hormone treatment of premenopausal and postmenopausal women (and men) with ER-positive early-stage breast cancer, andanastrozole and letrozole have been approved for this use in postmenopausal women.

A third aromatase inhibitorexemestane, is approved for adjuvant treatment of early-stage breast cancer in postmenopausal women who have received tamoxifen previously.

Until recently, most women who received adjuvant hormone therapy to reduce the chance of a breast cancer recurrence took tamoxifen every day for 5 years. However, with the advent of newer hormone therapies, some of which have been compared with tamoxifen in clinical trials, additional approaches to hormone therapy have become common (35). For example, some women may take an aromatase inhibitor every day for 5 years, instead of tamoxifen. Other women may receive additional treatment with an aromatase inhibitor after 5 years of tamoxifen. Finally, some women may switch to an aromatase inhibitor after 2 or 3 years of tamoxifen, for a total of 5 or more years of hormone therapy.

Decisions about the type and duration of adjuvant hormone therapy must be made on an individual basis. This complicated decision-making process is best carried out by talking with an oncologist, a doctor who specializes in cancer treatment.

Treatment of metastatic breast cancer: Several types of hormone therapy are approved to treat hormone-sensitive breast cancer that is metastatic (has spread to other parts of the body).

Studies have shown that tamoxifen is effective in treating women and men with metastatic breast cancer (6).Toremifene is also approved for this use. The antiestrogen fulvestrant can be used in postmenopausal women with metastatic ER-positive breast cancer after treatment with other antiestrogens (7).

The aromatase inhibitors anastrozole and letrozole can be given to postmenopausal women as initial therapy for metastatic hormone-sensitive breast cancer (89). These two drugs, as well as the aromatase inhibitor exemestane, can also be used to treat postmenopausal women with advanced breast cancer whose disease has worsened after treatment with tamoxifen (10).

Neoadjuvant treatment of breast cancer: The use of hormone therapy to treat breast cancer before surgery (neoadjuvant therapy) has been studied in clinical trials (11). The goal of neoadjuvant therapy is to reduce the size of a breast tumor to allow breast-conserving surgery. Data from randomized controlled trials have shown that neoadjuvant hormone therapies—in particular, aromatase inhibitors—can be effective in reducing the size of breast tumors in postmenopausal women. The results in premenopausal women are less clear because only a few small trials involving relatively few premenopausal women have been conducted thus far.

No hormone therapy has yet been approved by the FDA for the neoadjuvant treatment of breast cancer.

9.6.4 Hormone Therapy and Different Ovarian Cancers

Lina Steinrud Mørch, Ellen Løkkegaard, Anne Helms Andreasen, Susanne Krüger Kjær, Øjvind Lidegaard
Am J Epidemiol. 2012; 175(12):1234-1242

Postmenopausal hormone therapy use increases the risk of ovarian cancer. In the present study, the authors examined the risks of different histologic types of ovarian cancer associated with hormone therapy. Using Danish national registers, the authors identified 909,946 women who were followed from 1995–2005. The women were 50–79 years of age and had no prior hormone-sensitive cancers or bilateral oophorectomy. Hormone therapy prescription data were obtained from the National Register of Medicinal Product Statistics. The National Cancer and Pathology Register provided data on ovarian cancers, including information about tumor histology. The authors performed Poisson regression analyses that included hormone exposures and confounders as time-dependent covariates. In an average of 8.0 years of follow up, 2,681 cases of epithelial ovarian cancer were detected. Compared with never users, women taking unopposed oral estrogen therapy had increased risks of both serous tumors (incidence rate ratio (IRR) = 1.7, 95% confidence interval: 1.4, 2.2) and endometrioid tumors (IRR = 1.5, 95% confidence interval: 1.0, 2.4) but decreased risk of mucinous tumors (IRR = 0.3, 95% confidence interval: 0.1, 0.8). Similar increased risks of serous and endometrioid tumors were found with estrogen/progestin therapy, whereas no association was found with mucinous tumors. Consistent with results from recent cohort studies, the authors found that ovarian cancer risk varied according to tumor histology. The types of ovarian tumors should be given attention in future studies.


Ovarian cancer is the most lethal of gynecologic cancers. Unfortunately, little is known about its etiology. In recent meta-analyses, investigators have concluded that women taking postmenopausal hormone therapy (HT) have an increased risk of ovarian cancer compared with never users.[1, 2] Two large prospective studies, the Million Women Study and Danish Sex Hormone Register Study, found an overall increased risk of 30%–40%.[3, 4]

Less is known about the association between hormone use and the risk of different histologic subtypes of epithelial ovarian cancer. Other risk factors for ovarian cancer have been found to differ between mucinous and nonmucinous ovarian tumors, supporting the hypothesis of different etiologies.[5, 6]However, previous studies on HT and different types of ovarian tumors were mainly case-control studies, and the numbers of cases were small, especially for mucinous tumors.[1, 7–10] Most prospective cohort studies either did not examine tumor type[1, 4] or had incomplete information on histology.[11]

Recently, Danforth et al.[12] found that estrogen-only therapy (ET) was more strongly associated with the risk of endometrioid tumors than with the risk of other types of epithelial tumors in the Nurses’ Health Study (NHS). The Million Women Study found that with HT use, the highest risk was for serous tumors, whereas there was a lower risk of mucinous tumors.[3] Knowledge about the associations between HTs and subtypes of ovarian cancer will add to the understanding of how HT acts as a promoter of ovarian cancer carcinogenesis. Moreover, if different types of ovarian tumors are to be viewed as separate diseases, that fact should be considered when creating the study designs for future research. Therefore, the aim of the present study was to explore the risks of HT associated with different histologic types of ovarian cancer.

The study cohort was linked to the National Register of Medicinal Product Statistics using participants’ personal identification numbers as the key identifiers. The National Register of Medicinal Product Statistics includes information on the date of the redeemed prescriptions and the specific Anatomical Therapeutic Chemical code, dose, number of packages, defined daily doses, and route of administration (tablet, patch, gel, etc.) The specific Anatomical Therapeutic Chemical codes included in the present study have been described previously.[13]

The information on initiation of HT use (i.e., redeemed prescriptions) was updated daily for each individual during follow-up. The prescribed defined daily doses were used to determine the length of use. We included 4 months after the expiration of the prescription in all records of hormone exposure to account for any delay in recorded diagnoses in Danish registers, prolonged HT use for those taking less than the defined daily dose prescribed, and minor latency time. Thus, gaps between prescriptions of less than 4 month were filled prospectively; that is, a woman was classified as user of the drug at a given point in time if the dispensed supply from the last redemption had not run out or if it had run out within the last m days (where m is the allowed gap length).[14]

Because HT is likely to act as a promoter of ovarian cancer carcinogenesis with a yet unknown latency time, women currently taking hormones were categorized by the regimen that they took for the longest period during the study period. These variables were time varying; that is, if a woman began a new HT regimen, she would be recategorized if and when the time taking that regimen exceeded the amount of time she took the prior categorization HT regimen. The length of use was calculated as the time spent taking all systemic treatments during the study period. Whether a woman had taken hormones before 50 years of age but within the 11-year study period was accounted for in the hormone status categories, and the amount of time for which she took the hormones was accounted for in the duration of use category. The HT categories were HT use (never, past, current nonvaginal HT use, or other current use (i.e., current use of vaginal ET or a hormone intrauterine device)); hormone formulation (ET, estrogen/progestin therapy (EPT), or other (i.e., tibolone, raloxifene, progestin only, or vaginal estrogen)); hormone regimen (cyclic EPT, continuous EPT, or other); route of administration (oral ET, oral EPT or tibolone, dermal ET, dermal EPT, or other); duration of HT in years (never, current, 0.01–4 years, 4.01–7 years, or >7 years or use of vaginal ET or a hormone intrauterine device); and time since last use among former users (never, current, 0.01–2 years, 2.01–4 years, 4.01–6 years, or >6 years or use of vaginal ET or a hormone intrauterine device).

Ovarian Cancer Cases

Until December 31, 2002, we used the Danish Cancer Register to identify cases of primary invasive ovarian cancers and their histologies, using the International Classification of Diseases for Oncologytopography code 183.0 and morphology codes ending with a 3. At time of the present study, information from January 2003 had not been updated in the Danish Cancer Register. Thus, from 2003 onward, the Pathology Register was used for case findings and information on histology. The invasive epithelial tumors were classified as serous (codes M84413, M84603, M84613, and M90143), endometrioid (codes M83803 and M83813), mucinous (codes M84703, M84803, and M90153), clear-cell (codes M83103 and M83133), adenocarcinoma not otherwise specified (code M81403), or epithelial not otherwise specified (codes M80203, M80703, M81303, M85603, M89333, M89803, and M90003). Nonepithelial invasive tumors and borderline tumors were not included. Eight women for whom we did not have histologic information were excluded. Information on the stages of disease was available from the Danish Cancer Register until December 31, 2002.

From 1995 to 2005, a total of 909,946 perimenopausal and postmenopausal women with no previous cancer or removal of ovaries accumulated 7.3 million person-years of observation, corresponding to an average follow-up period of 8.0 years. The number of incident malignant epithelial ovarian cancers during the study period was 2,681. Of these, 1,336 were serous tumors, 377 were endometrioid tumors, 293 were mucinous tumors, 159 were clear-cell tumors, 115 were nonspecified epithelial tumors, and 401 were adenocarcinomas not otherwise specified. At the end of follow up, 63% of the women remained never users of HT, 22% were previous users, and 9% were current users. Compared with never users, hormone users were more likely to have undergone a hysterectomy (18.0% versus 6.2%) or unilateral salpingo-oophorectomy (5.7% versus 1.9%), to have been sterilized (8.4% versus 5.4%), and to be parous (80.8% versus 75.2%). The characteristics of the study population have been published previously.[4]

Compared with never users, current users of hormones had an increased risk of serous tumors (incidence rate ratio (IRR) = 1.7, 95% confidence interval (CI): 1.5, 1.9) and of endometrioid tumors (IRR = 1.7, 95% CI: 1.3, 2.2). Current use of hormones was not associated with the risk of mucinous or clear-cell tumors (Figure 1). The incidence rate ratios for serous ovarian cancer increased with duration of hormone use (0.01–4 years, IRR = 1.5, 95% CI: 1.3, 1.8; 4.01–7 years, IRR = 1.7, 95% CI: 1.4, 2.1; and >7 years, IRR = 2.1, 95% CI: 1.6, 2.8). The incidence rate ratios for other types of epithelial ovarian cancer were not consistently associated with duration of use (Figure 2).

(Enlarge Image)

Figure 1.

Incidence rate ratios of epithelial ovarian cancers associated with current use of hormone therapy, Danish Sex Hormone Register Study, 1995–2005. Values were adjusted for age, period of use, number of births, hysterectomy, sterilization, unilateral oophorectomy or salpingo-oophorectomy, endometriosis, infertility, and educational level. The reference group was never users of hormone therapy (dashed line). Bars, 95% confidence interval.

(Enlarge Image)

Figure 2.

Incidence rate ratios of epithelial ovarian cancers associated with durations of hormone therapy in years, Danish Sex Hormone Register Study, 1995–2005. Values were adjusted for age, period of use, number of births, hysterectomy, sterilization, unilateral oophorectomy or salpingo-oophorectomy, endometriosis, infertility, and educational level. The reference group was never users of hormone therapy (dashed line). Risk estimates for clear-cell cancer are not shown because there were few cases. Bars, 95% confidence interval.

Time Since Hormone Use

We found increased incidence rate ratios for serous ovarian cancers for a period of up to 2 years after cessation of HT. Thereafter, the risk approached that observed in never users. For endometrioid tumors, the risk was not significantly increased after cessation of HT (Figure 3).

(Enlarge Image)

Figure 3.

Incidence rate ratios of serous and endometrioid ovarian cancers associated with time since last hormone therapy use in years, Danish Sex Hormone Register Study, 1995–2005. Values were adjusted for age, period of use, number of births, hysterectomy, sterilization, unilateral oophorectomy or salpingo-oophorectomy, endometriosis, infertility, and educational level. The reference group was never users of hormone therapy (dashed line). Bars, 95% confidence interval.

Estrogen Therapy

Compared with never users, women on unopposed ET had an increased risk of serous tumors (IRR = 1.7, 95% CI: 1.4, 2.1) and a tendency toward an increased risk of endometrioid tumors (IRR = 1.4, 95% CI: 0.9, 2.1). In contrast, the risk of mucinous tumors was decreased (IRR = 0.3, 95% CI: 0.1, 0.8). No association was found between ET and the risk of clear-cell tumors (IRR = 0.6, 95% CI: 0.2, 1.5) (Figure 4).

(Enlarge Image)

Figure 4.

Incidence rate ratios of epithelial ovarian cancers associated with hormone therapy, Danish Sex Hormone Register Study, 1995–2005. A) Estrogen-only therapy; B) estrogen/progestin therapy. Values were adjusted for age, period of use, number of births, hysterectomy, sterilization, unilateral oophorectomy or salpingo-oophorectomy, endometriosis, infertility, and educational level. The reference group was never users of hormone therapy (dashed line). Bars, 95% confidence interval.

Women on oral ET had a statistically significantly increased risk of endometrioid tumors (IRR = 1.5, 95% CI: 1.0, 2.4), and the risks for serous, mucinous, and clear-cell tumors were similar to the risks found for all ET. Because the risk associations between transdermal ET and ovarian cancers were based on a few cases, the data are not shown. Vaginal estrogen alone was associated with an increased risk of serous tumors (IRR = 1.4, 95% CI: 1.1, 1.9), whereas no associations were found with endometrioid, mucinous, or clear-cell tumors (data not shown).

Combined Therapy

Women on combined EPT had increased incidence rate ratios for serous tumors (IRR = 1.6, 95% CI: 1.4, 1.9) and endometrioid tumors (IRR = 2.0, 95% CI: 1.5, 2.6), whereas no associations were found with mucinous or clear-cell tumors (Figure 4). Similar risk associations were found among women on oral EPT. Because there were few cases, data for transdermal EPT are not shown.

Duration of HT

The incidence rate ratios for serous ovarian cancer increased with increased duration of ET and after 7 years reached an incidence rate ratio of 2.9 (95% CI: 1.9, 4.3). The risks for endometrioid ovarian cancer were similar for all durations of ET (Table 1).

Among women on cyclic EPT, the risk of endometrioid ovarian cancer was increased by 70%–140%, whereas the risk was not increased among women on continuous EPT. The risks for serous ovarian cancer were similar regardless of the duration of cyclic or continuous EPT (Table 1). Results from crude and adjusted analyses were almost identical (data not shown).

Stage of Disease

Overall, the associations between HT and risks of different ovarian tumors did not change after adjustment for the stage of disease (Table 2). Although the analyses were slightly weakened by a lower number of cases, the results roughly showed similar incidence rate ratios across the stages of disease (Table 2).


The present large cohort study suggests that there is a differential influence of HT on different subtypes of ovarian cancer. Hormone users had an excess risk of serous and endometrioid tumors but not of mucinous and clear-cell cancers of the ovaries. Both combined EPT and unopposed ET were associated with increased risks of serous ovarian cancer. Furthermore, cyclic EPT and oral ET were associated with increased risks of endometrioid ovarian cancer. In contrast, no HT was associated with risk of clear-cell ovarian cancer, and women who had used ET had a decreased risk of mucinous ovarian cancer.

Serous Ovarian Cancer

Two large prospective cohort studies, the NHS and the Million Women Study, also found an increased risk of serous ovarian cancer among hormone users.[3, 12] In accordance with our finding, the Million Women Study reported an approximately 50% increased risk with HT.[3] The NHS supports our finding that increasing duration of ET is associated with increasing rate ratios for serous ovarian cancer.[12]

Endometrioid Ovarian Cancer

Although the Million Women Study found no association between any HT and the risk of endometrioid ovarian cancer, we found a 70% increased risk.[3] The NHS found a 50% increased risk of endometrioid tumors after 5 years of ET.[12] In our study, women on oral ET had an up to 2-fold increased risk of endometrioid tumors. Because ET increases the risk of endometrial cancer[15] and endometrioid ovarian tumors are histologically similar to endometrial tissue (16), it seems likely that ET acts through similar biologic mechanisms in the development of endometrioid ovarian cancer, a hypothesis suggested by Danforth et al..[12]

Furthermore, the present study suggests that women on cyclic EPT have an increased risk of endometrioid ovarian cancer, whereas the risk is not increased in women on continuous EPT. Only one study addressed the risk of endometrioid ovarian tumors among women on cyclic versus continuous EPT, and those investigators were not able to demonstrate an increased risk with cyclic or continuous EPT.[7] With regard to the development of endometrial cancer, the increased risk has been found to be confined to women on cyclic EPT.[15] Thus, it is possible that cyclic EPT acts through similar biologic mechanisms in the development of endometrioid ovarian cancer.

Mucinous Ovarian Cancer

Compared with women who were never prescribed HT, women on ET had a 70% decreased risk of mucinous ovarian cancer. The Million Women Study also found a decreased risk of approximately 30% with the use of HT.[3] A few other studies have also suggested that HT is associated with a decreased risk of mucinous ovarian cancer.[12, 17, 18] One group of mucinous tumors is similar to endocervical epithelium and another is similar to colonic epithelium.[16] Both HT in general and ET specifically have been found to decrease the risk of colon cancer.[19, 20] It therefore seems plausible that ET could also decrease the risk of mucinous ovarian cancer. Risch et al.[5] were the first to suggest different etiologies for mucinous and nonmucinous ovarian cancers, and a recent Danish study supported this hypothesis by suggesting significant differences in the risk between mucinous and nonmucinous tumors.[6]


Using the same data as in current study, Mørch et al.[4] found a 40% increase in the overall risk of ovarian cancer in current users of hormones, regardless of the duration and type of HT. However, in the present study, the risk of serous ovarian tumors increased with increasing durations of hormone use. This association was more pronounced among women using ET. After 7 years, the risk of serous ovarian cancer had increased 3-fold among women using ET compared with never users. On the other hand, restricting the analysis to mucinous tumors showed a decreased risk among women using ET. Thus, important information about a differential impact of HT, HT types, and associations with duration of hormone use are not described when different ovarian tumors are examined as a combined outcome.

Moreover, the clarification of the different associations between HT and subtypes of ovarian cancer adds to the understanding of how HT acts as a promoter of ovarian cancer carcinogenesis, as the results are in line with the current knowledge about HT-associated risks of cancers with similar epithelial origins. Because of this, it seems plausible that there is a causal association between HT and ovarian cancer. Other risk factors for ovarian cancer differ based on the type of tumor (mucinous vs. nonmucinous), supporting the hypothesis of different etiologies.[5, 6] The differences should be considered in research study design and suggest that different types of ovarian tumors should be viewed as separate diseases.

Strengths of Study

To our knowledge, our nationwide cohort study is the largest conducted thus far to explore the influence of HT on the risk of histologic subtypes of epithelial ovarian cancer. The validity of our outcome is considered to be high, as data from the Cancer Register validated the diagnoses (21–23). The agreement of histologic ovarian cancer diagnoses between the Pathology Register and the Cancer Register is high, and our estimates did not depend on the source of diagnoses.[24] The information on prescribed HT is transferred electronically from all Danish pharmacies by using bar codes, eliminating recall bias. Our information on both exposures and confounders was updated daily through the national registers, making it possible for us to account for changes in exposures. We excluded women with previous cancer because it might affect both the use of hormones and the subsequent risk of ovarian cancer. Our results were adjusted for age, time period, educational level, number of births, and history of hysterectomy, sterilization, unilateral oophorectomy, salpingo-oophorectomy, endometriosis, or infertility. There was, however, no significant confounding by any of the included variables. We found no evidence of earlier detection (surveillance bias) of ovarian tumors among women on HT. Finally, the stage of disease did not bias the differential association between HT and different tumor types.

Limitations of Study

Data from the National Register of Medicinal Product Statistics is not complete for the time period before January 1995. Thus, information about prescriptions for oral contraceptive use was not available for the women in current study who were 50 years of age or older from 1995−2005. Our incidence rate ratios may be underestimated because of confounding by use of oral contraceptives, as oral contraceptive use decreases the risk of ovarian cancer and often leads to HT.[25, 26] We were not able to restrict our analyses to nonobese women. The ovarian cancer risk associated with HT use is probably clearer in nonobese women (i.e., in women with a body mass index, measured as weight in kilograms divided by height in meters squared, <30).[27] Consequently, our results might be underestimated among nonobese. However, the Million Women Study adjusted data for oral contraceptive use, body mass index, age at menopause, alcohol consumption, smoking, and physical activity, and the adjustments did not result in material changes in their estimates.[3] Also, the NHS reported only minimal changes in the association between HT and the risk of ovarian cancer after adjustment for relevant potential confounders, including duration of oral contraceptive use, occurrence of natural menopause, and age at menarche.[12] The lack of information on family history of cancer might have caused an underestimation of risk in our results, as women with a family history of cancer are probably less likely to use hormones. Information on women who underwent surgical procedures was not available in the registers for the oldest women. Hysterectomy and oophorectomy reduce the risk of ovarian cancer and often lead to HT use, probably causing an underestimation of risk in older women in our results. However, despite our uneven adjustment for confounders, the risks for ovarian tumors were nearly identical across age groups.

9.6.5 Chemotherapy versus hormonal treatment in platinum- and paclitaxel-refractory ovarian cancer: a randomised trial of the German Arbeitsgemeinschaft Gynaekologische Onkologie (AGO) Study Group Ovarian Cancer

  1. du Bois, W. Meier, H. J. Lück, G. Emons, V. Moebus, et al.
    Ann Oncol (2002) 13 (2): 251-257

The majority of patients with ovarian cancer are not cured by first-line treatment.Until now, no study could demonstrate any substantial benefit when exposing ovarian cancer patients to second-line chemotherapy. However, most treatment regimens induce toxicity, thus negatively influencing the quality of rather limited life spans. Here we evaluate whether a second-line chemotherapy can offer any benefit compared with a less toxic hormonal treatment. Patients and methods Patients with ovarian cancer progressing during platinum-paclitaxel containing first-line therapy or experiencing relapse within 6 months were eligible. Patients were stratified for response to primary treatment (progression versus no change/response), and measurable versus non-measurable disease. Treatment consisted of either treosulfan 7 g/m2infused over 30 min or leuprorelin 3.75 mg injected subcutaneously or intramuscularly. Both regimens were repeated every 4 weeks. Results This study began in late 1996, and after 2.5 years accrual an interim analysis was performed when several investigators reported their concern about a suspected lack of efficacy. Following this analysis the recruitment was stopped early and the 78 patients already enrolled were followed up. The majority of patients received treatment until progressive disease was diagnosed or death occurred. Treatment delay was observed rarely and dose reduction was performed only in the treosulfan arm in 5% of 150 courses. Overall, both treatment arms were well tolerated. No objective responses were observed. The median survival time was 36 and 30 weeks in the treosulfan and leuprorelin arms, respectively. Overall survival did not differ between patients with relapse 3–6 months after first-line chemotherapy compared with patients with progressive disease within 3 months.

Conclusions The selected patient population represents a subgroup with extremely poor prognosis. Accordingly, results were not impressive. Both treatment arms showed favourable toxicity data, but failed to show remarkable activity, thus adding only limited evidence to the issue of whether patients with refractory ovarian cancer might benefit from second-line chemotherapy. Even stratified analysis did not identify any subgroup of patients in whom the administration of second-line chemotherapy could demonstrate a clinically relevant survival benefit.

Despite the considerable progress that has been achieved in the treatment of advanced ovarian cancer during the last de-cades, the majority of patients are still not cured by first-line treatment. Therefore, development of effective second-line treatment strategies remains a clinically relevant issue. Today standard first-line regimens in many countries contain both paclitaxel and a platinum analogue (e.g. cisplatin [12] or carboplatin [35]). There are only limited data available reporting results gained from second-line therapy following failure of this new first-line regimen. Until now, no guidelines for the selection of second-line treatment regimens have reached universal acceptance [6]. Furthermore, the definitions of recurrent or relapsed disease according to the status of platinum resistance [7] were solely based on data from patients who did not receive the actual standard first-line regimens containing paclitaxel, and therefore have to be re-evaluated. The treatment-free interval, which offers a chance of gaining a benefit from re-treatment with paclitaxel and/or platinum, remains to be defined. However, patients progressing during or relapsing shortly after platinum-paclitaxel probably have a poor prognosis and can be regarded as refractory to both of the drugs they were exposed to. Until now, no study has demonstrated clearly any substantial benefit for these patients when treating them with second-line chemotherapy. However, most treatment regimens induce toxicity, thus negatively influencing the quality of rather limited life spans in this strictly palliative setting. Therefore, the AGO Study Group set about evaluating whether a second-line chemotherapy could offer any benefit compared with a less toxic hormonal treatment.

The decision to use an alkylating agent for second-line chemotherapy was based on the assumption that these agents, which had been part of first-line treatment of ovarian cancer for decades, could offer some benefit as second-line agent after removal from first-line regimens. Treosulfan (Ovastat®, medac, Germany) was chosen as alkylating agent because it has been registered and used frequently in older first-line regimens in Germany, due to a more favourable non-haematological toxicity profile compared with cyclophosphamide [89]. The published data for treosulfan as second-line treatment after platinum failure had been partially contradictory. Two studies using intravenous treosulfan reported response rates of up to 20% in 25 and 72 patients, respectively [1011]. The latter trial included 43 patients with platinum refractory ovarian cancer and showed a 21% response rate. Orally administered treosulfan resulted in response rates of 3, 14 and 19% in 30, 22 and 16 platinum pre-treated patients, respectively [1214]. The only study reporting results of oral treosulfan in platinum refractory patients observed only one response in 30 patients. Therefore, we decided to use intravenous treosulfan as standard chemotherapy arm in this trial.

Leuprorelin (leuproreline acetate; Enantone®, Takeda, Germany), a gonadotropin-releasing hormone (GnRH) analogue, was selected as hormonal treatment in the experimental arm of this study. It could be administered in a similar time schedule as the chemotherapy regimen (monthly injections) and had shown some activity in previously reported studies in platinum pre-treated ovarian cancer. In these trials, leuprorelin had been used either as single agent [1517] or in combination with megestrole acetate or tamoxifen [1819]. Overall, nine responses have been reported in 46 platinum pre-treated patients [cumulative odds ratio (OR) 19.6%; 95% confidence interval (CI) 9% to 34%]. A retrospective review reported higher efficacy for leuprorelin compared with goserelin, thus providing further support for selecting leuprorelin in favour of other GnRH analogues [17]. However, platinum resistance had been reported inconsistently in all these studies, thus leaving some questions unanswered regarding efficiency in this particular group of patients. Toxicity profiles of leuprorelin had been uniformely reported as being mild, making this option potentially useful in this strictly palliative setting. Tamoxifen, another hormonal treatment with an 11% overall response rate reported in a meta-analysis in recurrent ovarian cancer [20], was not selected for this study, because the study group felt that the different mode of application could hamper comparability.

The median observation period was 22.5 months for all patients. The early termination of recruitment resulted in a statistical power of 80% to detect a 20% survival difference (50% versus 69.9%) after 6 months with two-sided testing and an α error of 0.05.

Treatment and tolerability

The majority of patients received treatment until progressive disease was diagnosed or death occurred. The mean and median treatment periods, respectively, were 18 and 16 weeks in the treosulfan arm, and 13 and 10 weeks in the leuprorelin arm. Treatment delay was observed rarely and median intervals per course were 30.8 and 28.6 days in the treosulfan and leuprorelin arms, respectively. Dose reduction was performed only in the treosulfan arm in eight of 150 courses (5%) because of myelosuppression.

Overall, 150 chemotherapy courses and 122 hormonal treatment courses were evaluable for toxicity. Haematological toxicities higher than grade 2 were observed in only a few patients. Thrombocytopenia grade 3/4 occurred in four and one courses in the treosulfan and leuprorelin arms, respectively. Neutropenia grade 3/4 was only observed in one course in each arm and no infections or neutropenic fever was reported. Anaemia greater than grade 2 was observed after seven courses in the treosulfan arm and after two courses in the leuprorelin arm.

Non-haematological toxicities grade 3 or 4 were reported in only few patients in both arms. Treosulfan induced nausea and emesis in 9% of patients compared with 6% of patients in the leuprorelin arm. Hot flushes were reported by one patient in each arm. Three further patients in the treosulfan arm reported grade 3 pain (two patients) and neurotoxicity (one). The latter was due to remaining toxicity from prior platinum-paclitaxel. Alopecia was common but was due to prior treatment. Re-growth of patients’ hair took longer in the treosulfan arm than in the leuprorelin arm. About one-third of patients still had alopecia after treatment with treosulfan compared with 11% in the leuprorelin arm. Fatigue was reported more frequently in the chemotherapy arm (eight of 36 patients versus one of 37 patients, treosulfan versus leuprorelin;P = 0.014, Fisher’s exact test). Overall, both treatment arms were relatively well tolerated resulting in only one treatment cessation due to toxicity.


No objective responses were observed in either of the treatment arms. Disease stabilisation lasting at least 4 weeks (no change) was reported in nine and four patients in the chemotherapy and hormonal treatment arm, respectively. All but one patient showed progressive disease within a median observation period of 22 months. Median progression-free survival was 17 weeks for treosulfan and 10 weeks for leuprorelin (P = 0.035, Wilcoxon test). The difference between both treatment arms remained significant in favour of treosulfan after adjusting for treatment-free interval before study entry (P = 0.028). However, after 6 months only 23% and 14% of patients in the treosulfan and leuprorelin arms had not progressed; corresponding figures for the 12 month observation period were 9% and 5%, respectively (Figure 1).

View larger version:

Figure 1. Progression-free survival (median 17 and 10 weeks for treosulfan and leuprorelin, respectively; P<0.05, log rank test; Kaplan–Meier curves).

At the time of this analysis, seven patients in the treosulfan arm and eight patients in the leuprorelin arm are still alive with disease [hazard ratio (HR) 0.98; 95% CI 0.58–1.67]. The differences observed between the treatment arms did not reach statistical significance (P = 0.87, Wilcoxon test; Figure2). Again, adjusting for a treatment-free interval before study entry did not alter results. The median survival time was 36 and 30 weeks in the treosulfan and leuprorelin arm, respectively. About one-third of patients in each arm were alive after 12 months.

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Figure 2. Survival (median 36 and 30 weeks for treosulfan and leuprorelin, respectively; P = 0.87, log rank test; Kaplan–Meier curves).

The impact of time to treatment failure after first-line chemo-therapy on second-line therapy efficacy was analysed bi-categorially. The cut-off was set at 13 weeks, thus comparing patients with progression under first-line therapy or early relapse within 3 months with patients who relapsed 3–6 months after completion of first-line chemotherapy. Overall, the difference between the groups with respect to progression-free survival did not reach statistical significance. Median progression-free survival was 11 and 12 weeks, respectively, for the two groups (P = 0.46, log rank test; HR 0.83; 95% CI 0.51–1.35). Furthermore, overall survival did not differ significantly between patients with relapse 3–6 months after first-line chemotherapy compared with patients with progressive disease within 3 months (P = 0.34, log rank test; HR 0.77; 95% CI 0.46–1.31). However, median survival was slightly superior in the group with a longer progression-free interval after first-line therapy (42 versus 25 weeks). The latter difference did not reach statistical significance and the Kaplan–Meier curves almost fell on top of each other shortly after 1 year of observation (data not shown).

The presence of bi-dimensionally measurable disease had a negative impact on treatment results. Patients with measurable disease showed a median progression-free survival of 11 weeks compared with 19 weeks in patients with non-measurable disease (P = 0.0006, log rank test). Again, overall survival was superior in the group of patients with non-measurable disease, but this difference did not reach statistical significance (median 47 versus 24 weeks; P = 0.18, log rank test). Only 29% of patients with measurable disease compared with 46% of patients with non-measurable disease were alive after 12 months (HR 1.93; 95% CI 0.73–5.16).

Subsequent treatment

In the treosulfan arm, 15 patients received third-line treatments, of whom three were changed over to leuprorelin. The remaining eight patients received: radiotherapy (one), tamoxifen (one) or chemotherapeutic drugs [topotecan (six), etoposide (one), liposomal doxorubicin (one), carboplatin (one), carboplatin-paclitaxel (one)]. Furthermore, 14 patients received fourth-line treatment, including tamoxifen (two), MPA (one), etoposide (two), topotecan (two), and one patient each idarubicin, gemcitabin or mitoxantrone i.p. Finally,three patients received fifth-line cyclophosphamide (one), etoposide (one) or radiotherapy (one). In the leuproreline arm, almost all patients received third-line therapy. Sixteen patients were crossed over to treosulfan, four received intraperitoneal mitoxantrone, two had liposomal doxorubicin and one patient each received etoposide, topotecan, carboplatin, paclitaxel-mitoxantrone or carboplatin-paclitaxel. Two patients received hormonal third-line treatment (one each received tamoxifen and MPA). Fourth-line treatment was offered to seven patients, including radiotherapy (one), topotecan (two), and one patient each liposomal doxorubicin-etoposide, etoposide or etoposide–5-fluorouracil (5-FU). Fifth-line treatment was offered to three patients, including paclitaxel, gemcitabin and 5-FU–platinum. The considerable use of third-line therapies after progression of disease might have hampered survival analysis, which in fact showed no significant difference between the treatment arms (although progression-free survival differed).

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This study represents a prospectively randomised trial in a very homogenous population. Only patients who were refractory to the standard first-line treatment of advanced ovarian cancer (i.e. platinum plus paclitaxel) were recruited. This selection represents a patient group with an extremely poor prognosis. At the moment, there is only limited evidence that these patients benefit from second-line chemotherapy at all, and more studies in this subgroup are necessary before any recommendations or guidelines can be established.

A randomised trial of the National Cancer Institute of Canada has shown an advantage for one arm over another when comparing 3-weekly topotecan days 1–5 to weekly topotecan in 78 patients, of whom 60% had received prior paclitaxel,and 60% were platinum refractory [23]. This advantage was limited to overall response (23% versus 8%). Progression-free survival differed only at a non-significant level (8 versus 13 weeks), and overall survival did not differ at all. Our trial showed a statistically significant advantage of one arm (treosulfan) with respect to progression-free survival, but failed to show any difference in overall survival. In addition, no differences with respect to response rates were observed. In fact, we did not observe any objective response. The latter could indicate a lack of activity of both study drugs, treosulfan and leuprorelin. However, even higher response rates as reported in the literature did not translate to longer progression-free and overall survival. A prospectively randomised trial comparing liposomal doxorubicin with topotecan included 254 platinum refractory patients; in addition, about two-thirds had received paclitaxel as part of prior therapy [24]. No significant differences were observed in the refractory subgroup: response rates were 7% and 12%, median progression-free survival was 9 and 14 weeks, and median survival was 33 and 37 weeks, respectively. Our observations of median progression free survival of 11 and 17 weeks and median survival of 30 and 36 weeks fit well with the reported data in this poor prognostic subgroup, although we did not observe any objective responses. Another randomised trial in 81 platinum refractory patients comparing paclitaxel with paclitaxel–epirubicin reported response rates of 17% and 34% translating to 2-year survival of 10% and 18% [25]. The corresponding 2-year survival in our trial was 19% and 22%, thus indicating the limited value of objective response rates as predictors for survival or progression-free survival in this poor prognostic subgroup of patients with truely refractory ovarian cancer.

Nevertheless, achieving an objective response might be beneficial in this palliative setting, especially if bulky tumours induce symptoms such as pain or bowl obstruction. However, objective response rates might not sufficiently reflect this potential benefit. Therefore, different response criteria that better reflect the palliative approach in these patients should be evaluated prospectively (e.g. symptom relief, reduction of pain medication or ability of enteral food intake). The development of better tools for the evaluation of genuine second-line chemotherapies becomes even more necessary when taking into account the fact that ovarian cancer becomes more of a chronic disease: mortality does not change substantially, but median and 5-year survival improves, thus indicating a growing need for efficient second-line and higher treatment. These therapies should allow tumour control and simultaneously should not reduce life quality.

This study reports mild toxicity data for both treatment arms, treosulfan and leuprorelin acetate, but, due to the very poor activity levels observed in both arms, adds only limited evidence to the issue of whether patients with refractory ovarian cancer benefit from second-line chemotherapy at all. Even stratified analysis in patients with progressive ovarian cancer versus patients experiencing relapse 3–6 months after first-line therapy, or patients with measurable versus non-measurable diseases, did not demonstrate any subgroup of patients in whom the administration of treosulfan second-line chemotherapy could demonstrate a clinically relevant benefit. Although a very short progression-free interval and the presence of bi-dimensionally measurable disease seemed to turn a bad prognosis into a worse prognosis, none of the differences between the strata showed a consistent and clinically relevant difference in survival. Only progression-free survival was influenced by these factors to some extent. Our data did not indicate that patients with a progression-free interval of >3 months but

However, results were disappointing in all subgroups. A rather small benefit was traded for a higher rate of fatigue in patients receiving chemotherapy. A gain of 6 weeks median progression-free survival in the superior chemotherapy arm in our study and some advantages with respect to response rates in other trials do not convincingly answer the question of whether second-line chemotherapy offers any benefit for patients with refractory ovarian cancer. Further studies are necessary to help to evaluate whether chemotherapy has a role in this subgroup of patients with a very unfavourable prognosis. A randomised comparison between best supportive care and the most active chemotherapy regimen available could theoretically be an appropriate design for such a trial. However, the German AGO investigators did not even broadly accept a randomisation between a hormonal treatment and a chemotherapy arm, as measured by an extremely slow recruitment rate. Furthermore, this study had to be closed prematurely after an interim analysis indicated only very limited activity in both treatment arms. A trial using best supportive care as one treatment arm would probably not be accepted either, although the above-mentioned efficacy data from chemotherapy studies do not provide more optimistic results.

Treosulfan showed an acceptable toxicity profile and at least some activity compared with leuprorelin acetate, thus allowing continuation of clinical research with this alkylating agent. Our subsequent trial in the refractory population compares treosulfan with topotecan (AGO protocol OVAR-2.3) and recruitment is much better, indicating that investigators more easily accept trials comparing two chemotherapy regimens. Quality of life evaluation was included in this protocol in an attempt to improve understanding of the nature of potential gains from second-line therapy.

Besides treosulfan and topotecan, which are further evaluated by our group, several chemotherapy agents have shown some activity in platinum- and paclitaxel-refractory ovarian cancer, and could serve as comparators in pending further trials: ifosfamide [26], hexamethylmelamine [27], gemcitabin [28] and liposomal doxorubicin [23,29]. The difficult task of recruiting large homogenous patient populations to second-line trials supports the ongoing discussions and activities in cooperative groups and networks, such as the worldwide Gynecologic Cancer InterGroup (GCIG), which is already planning and performing intergroup trials of second-line treatment of ovarian cancer.

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