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Multiple Lung Cancer Genomic Projects Suggest New Targets, Research Directions for Non-Small Cell Lung Cancer

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

lung cancer

(photo credit: cancer.gov)

A report Lung Cancer Genome Surveys Find Many Potential Drug Targets, in the NCI Bulletin,

http://www.cancer.gov/ncicancerbulletin/091812/page2

summarizes the clinical importance of five new lung cancer genome sequencing projects. These studies have identified genetic and epigenetic alterations in hundreds of lung tumors, of which some alterations could be taken advantage of using currently approved medications.

The reports, all published this month, included genomic information on more than 400 lung tumors. In addition to confirming genetic alterations previously tied to lung cancer, the studies identified other changes that may play a role in the disease.

Collectively, the studies covered the main forms of the disease—lung adenocarcinomas, squamous cell cancers of the lung, and small cell lung cancers.

“All of these studies say that lung cancers are genomically complex and genomically diverse,” said Dr. Matthew Meyerson of Harvard Medical School and the Dana-Farber Cancer Institute, who co-led several of the studies, including a large-scale analysis of squamous cell lung cancer by The Cancer Genome Atlas (TCGA) Research Network.

Some genes, Dr. Meyerson noted, were inactivated through different mechanisms in different tumors. He cautioned that little is known about alterations in DNA sequences that do not encode genes, which is most of the human genome.

Four of the papers are summarized below, with the first described in detail, as the Nature paper used a multi-‘omics strategy to evaluate expression, mutation, and signaling pathway activation in a large cohort of lung tumors. A literature informatics analysis is given for one of the papers.  Please note that links on GENE names usually refer to the GeneCard entry.

Paper 1. Comprehensive genomic characterization of squamous cell lung cancers[1]

The Cancer Genome Atlas Research Network Project just reported, in the journal Nature, the results of their comprehensive profiling of 230 resected lung adenocarcinomas. The multi-center teams employed analyses of

  • microRNA
  • Whole Exome Sequencing including
    • Exome mutation analysis
    • Gene copy number
    • Splicing alteration
  • Methylation
  • Proteomic analysis

Summary:

Some very interesting overall findings came out of this analysis including:

  • High rates of somatic mutations including activating mutations in common oncogenes
  • Newly described loss of function MGA mutations
  • Sex differences in EGFR and RBM10 mutations
  • driver roles for NF1, MET, ERBB2 and RITI identified in certain tumors
  • differential mutational pattern based on smoking history
  • splicing alterations driven by somatic genomic changes
  • MAPK and PI3K pathway activation identified by proteomics not explained by mutational analysis = UNEXPLAINED MECHANISM of PATHWAY ACTIVATION

however, given the plethora of data, and in light of a similar study results recently released, there appears to be a great need for additional mining of this CGAP dataset. Therefore I attempted to curate some of the findings along with some other recent news relevant to the surprising findings with relation to biomarker analysis.

Makeup of tumor samples

230 lung adenocarcinomas specimens were categorized by:

Subtype

33% acinar

25% solid

14% micro-papillary

9% papillary

8% unclassified

5% lepidic

4% invasive mucinous
Gender

Smoking status

81% of patients reported past of present smoking

The authors note that TCGA samples were combined with previous data for analysis purpose.

A detailed description of Methodology and the location of deposited data are given at the following addresses:

Publication TCGA Web Page: https://tcga-data.nci.nih.gov/docs/publications/luad_2014/

Sequence files: https://cghub.ucsc.edu

Results:

Gender and Smoking Habits Show different mutational patterns

 

WES mutational analysis

  1. a) smoking status

– there was a strong correlations of cytosine to adenine nucleotide transversions with past or present smoking. In fact smoking history separated into transversion high (past and previous smokers) and transversion low (never smokers) groups, corroborating previous results.

mutations in groups              Transversion High                   Transversion Low

TP53, KRAS, STK11,                 EGFR, RB1, PI3CA

     KEAP1, SMARCA4 RBM10

 

  1. b) Gender

Although gender differences in mutational profiles have been reported, the study found minimal number of significantly mutated genes correlated with gender. Notably:

  • EGFR mutations enriched in female cohort
  • RBM10 loss of function mutations enriched in male cohort

Although the study did not analyze the gender differences with smoking patterns, it was noted that RBM10 mutations among males were more prevalent in the transversion high group.

Whole exome Sequencing and copy number analysis reveal Unique, Candidate Driver Genes

Whole exome sequencing revealed that 62% of tumors contained mutations (either point or indel) in known cancer driver genes such as:

KRAS, EGFR, BRMF, ERBB2

However, authors looked at the WES data from the oncogene-negative tumors and found unique mutations not seen in the tumors containing canonical oncogenic mutations.

Unique potential driver mutations were found in

TP53, KEAP1, NF1, and RIT1

The genomics and expression data were backed up by a proteomics analysis of three pathways:

  1. MAPK pathway
  2. mTOR
  3. PI3K pathway

…. showing significant activation of all three pathways HOWEVER the analysis suggested that activation of signaling pathways COULD NOT be deduced from DNA sequencing alone. Phospho-proteomic analysis was required to determine the full extent of pathway modification.

For example, many tumors lacked an obvious mutation which could explain mTOR or MAPK activation.

 

Altered cell signaling pathways included:

  • Increased MAPK signaling due to activating KRAS
  • Higher mTOR due to inactivating STK11 leading to increased proliferation, translation

Pathway analysis of mutations revealed alterations in multiple cellular pathways including:

  • Reduced oxidative stress response
  • Nucleosome remodeling
  • RNA splicing
  • Cell cycle progression
  • Histone methylation

Summary:

Authors noted some interesting conclusions including:

  1. MET and ERBB2 amplification and mutations in NF1 and RIT1 may be unique driver events in lung adenocarcinoma
  2. Possible new drug development could be targeted to the RTK/RAS/RAF pathway
  3. MYC pathway as another important target
  4. Cluster analysis using multimodal omics approach identifies tumors based on single-gene driver events while other tumor have multiple driver mutational events (TUMOR HETEROGENEITY)

Paper 2. A Genomics-Based Classification of Human Lung Tumors[2]

The paper can be found at

http://stm.sciencemag.org/content/5/209/209ra153

by The Clinical Lung Cancer Genome Project (CLCGP) and Network Genomic Medicine (NGM),*,

Paper Summary

This sequencing project revealed discrepancies between histologic and genomic classification of lung tumors.

Methodology

– mutational analysis by whole exome sequencing of 1255 lung tumors of histologically

defined subtypes

– immunohistochemistry performed to verify reclassification of subtypes based on sequencing data

Results

  • 55% of all cases had at least one oncogenic alteration amenable to current personalized treatment approaches
  • Marked differences existed between cluster analysis within and between preclassified histo-subtypes
  • Reassignment based on genomic data eliminated large cell carcinomas
  • Prospective classification of 5145 lung cancers allowed for genomic classification in 75% of patients
  • Identification of EGFR and ALK mutations led to improved outcomes

Conclusions:

It is feasible to successfully classify and diagnose lung tumors based on whole exome sequencing data.

Paper 3. Genomic Landscape of Non-Small Cell Lung Cancer in Smokers and Never-Smokers[3]

A link to the paper can be found here with Graphic Summary: http://www.cell.com/cell/abstract/S0092-8674%2812%2901022-7?cc=y?cc=y

Methodology

  • Whole genome sequencing and transcriptome sequencing of cancerous and adjacent normal tissues from 17 patients with NSCLC
  • Integrated RNASeq with WES for analysis of
    • Variant analysis
    • Clonality by variant allele frequency anlaysis
    • Fusion genes
  • Bioinformatic analysis

Results

  • 3,726 point mutations and more than 90 indels in the coding sequence
  • Smokers with lung cancer show 10× the number of point mutations than never-smokers
  • Novel lung cancer genes, including DACH1, CFTR, RELN, ABCB5, and HGF were identified
  • Tumor samples from males showed high frequency of MYCBP2 MYCBP2 involved in transcriptional regulation of MYC.
  • Variant allele frequency analysis revealed 10/17 tumors were at least biclonal while 7/17 tumors were monoclonal revealing majority of tumors displayed tumor heterogeneity
  • Novel pathway alterations in lung cancer include cell-cycle and JAK-STAT pathways
  • 14 fusion proteins found, including ROS1-ALK fusion. ROS1-ALK fusions have been frequently found in lung cancer and is indicative of poor prognosis[4].
  • Novel metabolic enzyme fusions
  • Alterations were identified in 54 genes for which targeted drugs are available.           Drug-gable mutant targets include: AURKC, BRAF, HGF, EGFR, ERBB4, FGFR1, MET, JAK2, JAK3, HDAC2, HDAC6, HDAC9, BIRC6, ITGB1, ITGB3, MMP2, PRKCB, PIK3CG, TERT, KRAS, MMP14

Table. Validated Gene-Fusions Obtained from Ref-Seq Data

Note: Gene columns contain links for GeneCard while Gene function links are to the    gene’s GO (Gene Ontology) function.

GeneA (5′) GeneB (3′) GeneA function (link to Gene Ontology) GeneB function (link to Gene Ontology) known function (refs)
GRIP1 TNIP1 glutamate receptor IP transcriptional repressor
SGMS1 STK10 sphingolipid synthesis ser/thr kinase
RASSF3 TTYH2 GTP-binding protein chloride anion channel
KDELR2 ROS1, GOPC ER retention seq. binding proto-oncogenic tyr kinase
ACSL4 DCAF6 fatty acid synthesis ?
MARCH8 PRKG1 ubiquitin ligase cGMP dependent protein kinase
APAF1 UNC13B, TLN1 caspase activation cytoskeletal
EML4 ALK microtubule protein tyrosine kinase
EDR3,PHC3 LOC441601 polycomb pr/DNA binding ?
DKFZp761L1918,RHPN2 ANKRD27 Rhophilin (GTP binding pr ankyrin like
VANGL1 HAO2 tetraspanin family oxidase
CACNA2D3 FLNB VOC Ca++ channel filamin (actin binding)

Author’s Note:

There has been a recent literature on the importance of the EML4-ALK fusion protein in lung cancer. EML4-ALK positive lung tumors were found to be les chemo sensitive to cytotoxic therapy[5] and these tumor cells may exhibit an epitope rendering these tumors amenable to immunotherapy[6]. In addition, inhibition of the PI3K pathway has sensitized EMl4-ALK fusion positive tumors to ALK-targeted therapy[7]. EML4-ALK fusion positive tumors show dependence on the HSP90 chaperone, suggesting this cohort of patients might benefit from the new HSP90 inhibitors recently being developed[8].

Table. Significantly mutated genes (point mutations, insertions/deletions) with associated function.

Gene Function
TP53 tumor suppressor
KRAS oncogene
ZFHX4 zinc finger DNA binding
DACH1 transcription factor
EGFR epidermal growth factor receptor
EPHA3 receptor tyrosine kinase
ENSG00000205044
RELN cell matrix protein
ABCB5 ABC Drug Transporter

Table. Literature Analysis of pathways containing significantly altered genes in NSCLC reveal putative targets and risk factors, linkage between other tumor types, and research areas for further investigation.

Note: Significantly mutated genes, obtained from WES, were subjected to pathway analysis (KEGG Pathway Analysis) in order to see which pathways contained signicantly altered gene networks. This pathway term was then used for PubMed literature search together with terms “lung cancer”, “gene”, and “NOT review” to determine frequency of literature coverage for each pathway in lung cancer. Links are to the PubMEd search results.

KEGG pathway Name # of PUBMed entries containing Pathway Name, Gene ANDLung Cancer
Cell cycle 1237
Cell adhesion molecules (CAMs) 372
Glioma 294
Melanoma 219
Colorectal cancer 207
Calcium signaling pathway 175
Prostate cancer 166
MAPK signaling pathway 162
Pancreatic cancer 88
Bladder cancer 74
Renal cell carcinoma 68
Focal adhesion 63
Regulation of actin cytoskeleton 34
Thyroid cancer 32
Salivary secretion 19
Jak-STAT signaling pathway 16
Natural killer cell mediated cytotoxicity 11
Gap junction 11
Endometrial cancer 11
Long-term depression 9
Axon guidance 8
Cytokine-cytokine receptor interaction 8
Chronic myeloid leukemia 7
ErbB signaling pathway 7
Arginine and proline metabolism 6
Maturity onset diabetes of the young 6
Neuroactive ligand-receptor interaction 4
Aldosterone-regulated sodium reabsorption 2
Systemic lupus erythematosus 2
Olfactory transduction 1
Huntington’s disease 1
Chemokine signaling pathway 1
Cardiac muscle contraction 1
Amyotrophic lateral sclerosis (ALS) 1

A few interesting genetic risk factors and possible additional targets for NSCLC were deduced from analysis of the above table of literature including HIF1-α, mIR-31, UBQLN1, ACE, mIR-193a, SRSF1. In addition, glioma, melanoma, colorectal, and prostate and lung cancer share many validated mutations, and possibly similar tumor driver mutations.

KEGGinliteroanalysislungcancer

 please click on graph for larger view

Paper 4. Mapping the Hallmarks of Lung Adenocarcinoma with Massively Parallel Sequencing[9]

For full paper and graphical summary please follow the link: http://www.cell.com/cell/abstract/S0092-8674%2812%2901061-6

Highlights

  • Exome and genome characterization of somatic alterations in 183 lung adenocarcinomas
  • 12 somatic mutations/megabase
  • U2AF1, RBM10, and ARID1A are among newly identified recurrently mutated genes
  • Structural variants include activating in-frame fusion of EGFR
  • Epigenetic and RNA deregulation proposed as a potential lung adenocarcinoma hallmark

Summary

Lung adenocarcinoma, the most common subtype of non-small cell lung cancer, is responsible for more than 500,000 deaths per year worldwide. Here, we report exome and genome sequences of 183 lung adenocarcinoma tumor/normal DNA pairs. These analyses revealed a mean exonic somatic mutation rate of 12.0 events/megabase and identified the majority of genes previously reported as significantly mutated in lung adenocarcinoma. In addition, we identified statistically recurrent somatic mutations in the splicing factor gene U2AF1 and truncating mutations affecting RBM10 and ARID1A. Analysis of nucleotide context-specific mutation signatures grouped the sample set into distinct clusters that correlated with smoking history and alterations of reported lung adenocarcinoma genes. Whole-genome sequence analysis revealed frequent structural rearrangements, including in-frame exonic alterations within EGFR and SIK2 kinases. The candidate genes identified in this study are attractive targets for biological characterization and therapeutic targeting of lung adenocarcinoma.

Paper 5. Integrative genome analyses identify key somatic driver mutations of small-cell lung cancer[10]

Highlights

  • Whole exome and transcriptome (RNASeq) sequencing 29 small-cell lung carcinomas
  • High mutation rate 7.4 protein-changing mutations/million base pairs
  • Inactivating mutations in TP53 and RB1
  • Functional mutations in CREBBP, EP300, MLL, PTEN, SLIT2, EPHA7, FGFR1 (determined by literature and database mining)
  • The mutational spectrum seen in human data also present in a Tp53-/- Rb1-/- mouse lung tumor model

 

Curator Graphical Summary of Interesting Findings From the Above Studies

DGRAPHICSUMMARYNSLCSEQPOST

The above figure (please click on figure) represents themes and findings resulting from the aforementioned studies including

questions which will be addressed in Future Posts on this site.

References:

  1. Comprehensive genomic characterization of squamous cell lung cancers. Nature 2012, 489(7417):519-525.
  2. A genomics-based classification of human lung tumors. Science translational medicine 2013, 5(209):209ra153.
  3. Govindan R, Ding L, Griffith M, Subramanian J, Dees ND, Kanchi KL, Maher CA, Fulton R, Fulton L, Wallis J et al: Genomic landscape of non-small cell lung cancer in smokers and never-smokers. Cell 2012, 150(6):1121-1134.
  4. Takeuchi K, Soda M, Togashi Y, Suzuki R, Sakata S, Hatano S, Asaka R, Hamanaka W, Ninomiya H, Uehara H et al: RET, ROS1 and ALK fusions in lung cancer. Nature medicine 2012, 18(3):378-381.
  5. Morodomi Y, Takenoyama M, Inamasu E, Toyozawa R, Kojo M, Toyokawa G, Shiraishi Y, Takenaka T, Hirai F, Yamaguchi M et al: Non-small cell lung cancer patients with EML4-ALK fusion gene are insensitive to cytotoxic chemotherapy. Anticancer research 2014, 34(7):3825-3830.
  6. Yoshimura M, Tada Y, Ofuzi K, Yamamoto M, Nakatsura T: Identification of a novel HLA-A 02:01-restricted cytotoxic T lymphocyte epitope derived from the EML4-ALK fusion gene. Oncology reports 2014, 32(1):33-39.
  7. Yang L, Li G, Zhao L, Pan F, Qiang J, Han S: Blocking the PI3K pathway enhances the efficacy of ALK-targeted therapy in EML4-ALK-positive nonsmall-cell lung cancer. Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine 2014.
  8. Workman P, van Montfort R: EML4-ALK fusions: propelling cancer but creating exploitable chaperone dependence. Cancer discovery 2014, 4(6):642-645.
  9. Imielinski M, Berger AH, Hammerman PS, Hernandez B, Pugh TJ, Hodis E, Cho J, Suh J, Capelletti M, Sivachenko A et al: Mapping the hallmarks of lung adenocarcinoma with massively parallel sequencing. Cell 2012, 150(6):1107-1120.
  10. Peifer M, Fernandez-Cuesta L, Sos ML, George J, Seidel D, Kasper LH, Plenker D, Leenders F, Sun R, Zander T et al: Integrative genome analyses identify key somatic driver mutations of small-cell lung cancer. Nature genetics 2012, 44(10):1104-1110.

Other posts on this site which refer to Lung Cancer and Cancer Genome Sequencing include:

Multi-drug, Multi-arm, Biomarker-driven Clinical Trial for patients with Squamous Cell Carcinoma called the Lung Cancer Master Protocol, or Lung-MAP launched by NCI, Foundation Medicine, and Five Pharma Firms

US Personalized Cancer Genome Sequencing Market Outlook 2018 –

Comprehensive Genomic Characterization of Squamous Cell Lung Cancers

International Cancer Genome Consortium Website has 71 Committed Cancer Genome Projects Ongoing

Non-small Cell Lung Cancer drugs – where does the Future lie?

Lung cancer breathalyzer trialed in the UK

Diagnosing Lung Cancer in Exhaled Breath using Gold Nanoparticles

Multi-drug, Multi-arm, Biomarker-driven Clinical Trial for patients with Squamous Cell Carcinoma called the Lung Cancer Master Protocol, or Lung-MAP launched by NCI, Foundation Medicine, and Five Pharma Firms

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Genomics-Based Classification

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

and

Curator: Aviva Lev-Ari, PhD, RN

 

This article is a recently reported use of genomics to classify lung cancer published in Science Translational Medicine.

A Genomics-Based Classification of Human Lung Tumors

Sci Transl Med 30 Oct 2013;  5(209), p. 209ra153     http://dx.doi.org/10.1126/scitranslmed.3006802
The Clinical Lung Cancer Genome Project (CLCGP) and Network Genomic Medicine (NGM),*,†
 ↵†Corresponding authors. E-mail: roman.thomas@uni-koeln.de (R.T.); reinhard.buettner@uk-koeln.de (R.B.); juergen.wolf@uk-koeln.de (J.W.)
 ↵* Lists of participants and their affiliations appear at the end of the paper.
Abstract
We characterized genome alterations in 1255 clinically annotated lung tumors of all histological subgroups to identify genetically defined and clinically relevant subtypes. More than 55% of all cases had at least one oncogenic genome alteration
  • potentially amenable to specific therapeutic intervention, including
  • several personalized treatment approaches that are already in clinical evaluation.
Marked differences in the pattern of genomic alterations existed between and within histological subtypes, thus
  • challenging the original histomorphological diagnosis.
  • Immunohistochemical studies confirmed many of these reassigned subtypes.
  • The reassignment eliminated almost all cases of large cell carcinomas,

some of which had therapeutically relevant alterations. Prospective testing of our genomics-based diagnostic algorithm in 5145 lung cancer patients enabled

  • a genome-based diagnosis in 3863 (75%) patients,
  • confirmed the feasibility of rational reassignments of large cell lung cancer, and
  • led to improvement in overall survival in patients with EGFR-mutant or ALK-rearranged cancers.
Thus, our findings provide support for broad implementation of genome-based diagnosis of lung cancer.

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FDA approves EGFR mutation detection test for NSCLC drug, Tarceva

Author/Reporter: Ritu Saxena, Ph.D.

The cobas EGFR Mutation Test, Roche Molecular Diagnostics, identifies mutations in epidermal growth factor receptor (EGFR) exons 18, 19, 20 and 21 of patients. The FDA has approved the companion diagnostic for the cancer drug Tarceva (erlotinib). It would select non-small cell lung cancer (NSCLC) patients for treatment with EGFR inhibitors. This is the first FDA-approved companion diagnostic that detects EGFR gene mutations, which are present in approximately 10-30% of non-small cell lung cancers (NSCLC). The test is being approved with an expanded use for Tarceva as a first-line treatment for patients with NSCLC that has metastasized and who have certain mutations in the EGFR gene.

Lung cancer, the leading cause of cancer death among both men and women leads to death of more people than colon, breast, and prostate cancers combined. The American Cancer Society’s most recent estimates for lung cancer in the United States for 2012 reveal that about 226,160 new cases of lung cancer will be diagnosed (116,470 in men and 109,690 in women), and there will be an estimated 160,340 deaths from lung cancer (87,750 in men and 72,590 among women), accounting for about 28% of all cancer deaths. NSCLC is the most common type of lung cancer and usually grows and spreads more slowly than small cell lung cancer. Activating EGFR mutations occur in 10–30% NSCLC cases, and lead to hyperdependence of tumors on EGFR signaling and increased sensitivity of EGFR to inhibition by erlotinib. Genentech/OSI Pharmaceuticals/Roche/Chugai Pharmaceutical’s erlotinib (Tarceva) is a small molecule quinazoline and directly and reversibly inhibits the EGFR tyrosine kinase.

Tarceva has been indicated for first-line treatment of cancer with EGFR mutations including NSCLC. The approval is Tarceva’s fourth indication and the third use for lung cancer. The FDA approved Tarceva on April 16, 2010, for maintenance treatment of patients with locally advanced or metastatic NSCLC whose disease has not progressed after four cycles of platinum-based first-line chemotherapy. Tarceva was originally approved in November 2004 for the treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen.

In a recent multicenter, open label, randomized, phase III clinical trial (EURTAC trial; NCT0044625; http://clinicaltrials.gov/ct2/show/NCT00446225 ), Tarceva was investigated in patients with advanced NSCLC with mutations in the tyrosine kinase (TK) domain of the EGFR. The EURTAC trial was initiated in February 2007 and completed in December 2012 and enrolled around 174 patients. Patients were divided into two experimental arms. Patients in arm 1 were administered Tarceva (150 mg/day) while patients in arm 2 underwent chemotherapy as platinum-based doublets. The chemotherapeutic drugs were administered as Cisplatin (75 mg/m2) / Docetaxel (75 mg/m2); Cisplatin (75 mg/m2) / Gemcitabine (1250 mg/m2; day 1 and 8); Docetaxel (75 mg/m2) /carboplatin (AUC=6); Gemcitabine (1000 mg/m2; day 1 and 8) / Carboplatin (AUC=5). Results revealed that Erlotinib is better tolerated in Chinese population (grade 3-4 toxicities 17%) then in European patients (grade 3-4 toxicities 45%). Erlotinib scored significantly better than chemotherapy in terms of progression-free survival (PFS) with 9.7 versus 5.2 months, respectively (HR 0.37, 95% CI 0.25-0.54). Thus, the results of the trial strengthen the rationale for routine baseline tissue-based assessment of EGFR mutations in patients with NSCLC and for treatment of mutation-positive patients with EGFR tyrosine-kinase inhibitors. (Gridelli C and Rossi A, J Thorac Dis. 2012 Apr 1;4(2):219-20; http://www.ncbi.nlm.nih.gov/pubmed/22833832 )

In conclusion, FDA approval of cobas EGFR Mutation Test is a recent example of how genotyping patients in clinical trials could lead to crucial information regarding personalizing the diagnostic and therapeutic approaches.

Reference:

News brief

Clinical lab products http://www.clpmag.com/all-news/24074-fda-approves-first-companion-diagnostic-to-detect-gene-mutation-linked-with-a-type-of-lung-cancer

Clinical trial http://clinicaltrials.gov/ct2/show/NCT00446225

Research articles

Melosky B. EURTAC first line therapy for non small cell lung carcinoma in epidermal growth factor receptor mutation positive patients: A choice between two TKIs. J Thorac Dis. 2012 Apr 1;4(2):221-2; http://www.ncbi.nlm.nih.gov/pubmed/22833833

Gridelli C and Rossi AJ. EURTAC first-line phase III randomized study in advanced non-small cell lung cancer: Erlotinib works also in European population. Thorac Dis. 2012 Apr 1;4(2):219-20; http://www.ncbi.nlm.nih.gov/pubmed/22833832

Related reading

Nguyen KS and Neal JW. First-line treatment of EGFR-mutant non-small-cell lung cancer: the role of erlotinib and other tyrosine kinase inhibitors. Biologics. 2012;6:337-45; http://www.ncbi.nlm.nih.gov/pubmed/23055691

https://pharmaceuticalintelligence.com/2012/11/06/non-small-cell-lung-cancer-drugs-where-does-the-future-lie/ Curator: Ritu Saxena, Ph.D.

https://pharmaceuticalintelligence.com/2013/03/03/personalized-medicine-in-nsclc/ Curator: Larry H. Bernstein, M.D.

https://pharmaceuticalintelligence.com/2012/11/08/lung-cancer-nsclc-drug-administration-and-nanotechnology/ Author: Tilda Barliya, Ph.D.

https://pharmaceuticalintelligence.com/2012/09/18/personalized-rx-decisions-in-nsclc-treatments-symposium-in-thoracic-oncology/ Reporter: Aviva Lev-Ari, Ph.D., R.N.

https://pharmaceuticalintelligence.com/2013/05/15/diagnosis-of-cardiovascular-disease-treatment-and-prevention-current-predicted-cost-of-care-and-the-promise-of-individualized-medicine-using-clinical-decision-support-systems/ Author/Curator: Larry H. Bernstein, M.D.

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Causes and imaging features of false positives and false negatives on 18F-PET/CT in oncologic imaging

 Reporter: Dror Nir, PhD

Early this year I have posted on: Whole-body imaging as cancer screening tool; answering an unmet clinical need? F-PET/CT was discussed in this post as a leading modality in that respect. Here I report on an article dedicated to the sources for misdiagnosis; i.e. false negatives and false positives when applying this technology:

Causes and imaging features of false positives and false negatives on 18F-PET/CT in oncologic imaging, Niamh M. Long and Clare S. Smith /Insights into Imaging© European Society of Radiology 201010.1007/s13244-010-0062-3

Abstract

Background

18F-FDG is a glucose analogue that is taken up by a wide range of malignancies. 18F-FDG PET-CT is now firmly established as an accurate method for the staging and restaging of various cancers. However, 18F-FDG also accumulates in normal tissue and other non-malignant conditions, and some malignancies do not take up F18-FDG or have a low affinity for the tracer, leading to false-positive and false-negative interpretations.

Methods

PET-CT allows for the correlation of two separate imaging modalities, combining both morphological and metabolic information. We should use the CT to help interpret the PET findings. In this article we will highlight specific false-negative and false-positive findings that one should be aware of when interpreting oncology scans.

Results

We aim to highlight post-treatment conditions that are encountered routinely on restaging scans that can lead to false-positive interpretations. We will emphasise the importance of using the CT component to help recognise these entities to allow improved diagnostic accuracy.

Conclusion

In light of the increased use of PET-CT, it is important that nuclear medicine physicians and radiologists be aware of these conditions and correlate the PET and CT components to avoid misdiagnosis, over staging of disease and unnecessary biopsies.

Introduction

[18F] 2-fluoro-2deoxy-D-glucose (18F-FDG) PET-CT imaging has become firmly established as an excellent clinical tool in the diagnosis, staging and restaging of cancer. 18F-FDG (a glucose analog) is taken up by cells via glucose transporter proteins. The glucose analog then undergoes phosphorylation by hexokinase to FDG-6 phosphate. Unlike glucose, FDG-phosphate does not undergo further metabolism and so becomes trapped in the cell as the cell membrane is impermeable to FDG-6 phosphate following phosphorylation [1].

Malignant tumors have a higher metabolic rate and generally express higher numbers of specific membrane transporter proteins than normal cells. This results in increased uptake of 18F-FDG by tumor cells and forms the basis of FDG-PET imaging [2]. Glucose however acts as a basic energy substrate for many tissues, and so 18F-FDG activity can be seen both physiologically and in benign conditions. In addition, not all tumors take up FDG [35]. The challenge for the interpreting physician is to recognize these entities and avoid the many pitfalls associated with 18F-FDG PET-CT imaging.

In this article we discuss false-positive and false-negative 18F-FDG PET-CT findings, common and atypical physiological sites of FDG uptake, and benign pathological causes of FDG uptake. We will focus on post-treatment conditions that can result in false-positive findings. We will highlight the importance of utilizing the CT component of the study, not only for attenuation correction but also in the interpretation of the study. The CT component of 18F-FDG PET-CT imaging can provide high-resolution anatomical information, which enables more accurate staging and assessment. For the purposes of this article, we refer to the descriptive terms “false-positive” and “false-negative” findings in the context of oncology imaging.

The authors acknowledge that there are recognized causes of FDG uptake that are not related to malignancy; however in this paper we refer to false-positive findings as FDG uptake that is not tumor related.

Patient preparation

Tumor uptake of FDG is reduced in the presence of raised serum glucose as glucose competes with FDG for uptake by the membrane transporter proteins. In order to prevent false-negative results, it is necessary for the patient to fast for at least 4–6 h prior to the procedure [6]. Induction of a euglycamic hypoinsulinaemic state also serves to reduce the uptake of glucose by the myocardium and skeletal muscle. In the fasting state, the decreased availability of glucose results in predominant metabolism of fatty acids by the myocardium. This reduces the intensity of myocardial uptake and prevents masking of metastatic disease within the mediastinum [6].

The radiotracer is administered intravenously (dose dependent on both the count rate capability of the system used and the patient’s weight), and the patient is left resting in a comfortable position during the uptake phase (60–90 min). Patient discomfort and anxiety can result in increased uptake in skeletal muscles of the neck and paravertebral regions. Muscular contraction immediately prior to or following injection can result in increased FDG activity in major muscle groups [6].

Patients are placed in a warm, quiet room with little stimulation, as speech during the uptake phase is associated with increased FDG uptake in the laryngeal muscles [7].

At our institution we perform the CT component with arms up except for head and neck studies where the arms are placed down by the side. This minimizes artifacts on CT. Depending on the type of cancer, oral contrast to label the bowel and intravenous contrast may also be given. The CT is performed with a full dose similar to a diagnostic CT, and lungs are analyzed following reconstruction with a lung algorithm. The PET scan is performed with 3–4 min per bed position; however the time per bed position will vary in different centers depending on both the dose of FDG administered and the specifications of the camera used for image acquisition. It is beyond the scope of this article to provide detailed procedure guidelines for 18F-FDG PET-CT imaging, and for this purpose we refer the reader to a comprehensive paper by Boellaard et al. [8].

Technical causes of false positives

Misregistration artifact

The evaluation of pulmonary nodules provides a unique challenge for combined PET-CT scanning due to differences in breathing patterns between CT and PET acquisition periods. CT imaging of the thorax is classically performed during a breath-hold; however PET images are acquired during tidal breathing, and this can contribute significantly to misregistration of pulmonary nodules on fused PET-CT images. Misregistration is particularly evident at the lung bases, which can lead to difficulty differentiating pulmonary nodules from focal liver lesions (Fig. 1) [9].

f1

Fig. 1

18F-FDG PET-CT performed in a 65-year-old male with colorectal cancer. On the coronal PET images, a focus of increased FDG uptake is seen at the right lung base (black arrow). Contrast CT does not show any pulmonary nodules but does demonstrate a liver metastasis in the superior aspect of the right lobe of the liver (yellow arrow)

Acquiring CT imaging of the thorax during quiet respiration can help to minimize misregistration artifacts. It is also important to correlate your PET and CT findings by scrolling up and down to make sure that lesions match.

Injected clot

A further diagnostic pitfall in staging of intrathoracic disease can be caused by injected clot. Injection of radioactive clot following blood withdrawal into the syringe at the time of radiotracer administration can result in pulmonary hotspots [10]. The absence of a CT correlate for a pulmonary hotspot should raise the possibility of injected clot; however this is a diagnosis of exclusion, and it is important to carefully evaluate the adjacent slices to ensure the increased radiotracer activity does not relate to misregistration of a pulmonary nodule or hilar lymph node. The area of abnormal radiotracer uptake should also be closely evaluated on subsequent restaging CT to ensure there has been no interval development of an anatomical abnormality in the region of previously diagnosed injected clot (Fig. 2) [11].

f2

Fig. 2

18F-FDG PET-CT performed in a 28-year-old male with an osteosarcoma of the femur. A focus of increased FDG uptake (yellow arrow) is identified in the left lower lobe with no CT correlate (a). A 3-month follow-up CT thorax again does not demonstrate any pulmonary nodules confirming that the uptake seen originally on the PET-CT was due to injected clot (b)

Injection artifact

Leakage of radiotracer into the subcutaneous tissues at the injection site or tissued injection can result in subcutaneous tracking of FDG along lymphatic channels in the arm. This can result in spurious uptake in axillary nodes distal to the injection site [12]. Careful attention must be paid to the technical aspects of the study to ensure accurate staging. Injection at the side contralateral to the site of disease is advised where feasible to allow differentiation between artifactual and metastatic uptake, particularly in breast cancer patients. The side of injection should also be clearly documented during administration of radiotracer, and this information should be available to the reader in order to ensure pathological FDG uptake is not spuriously attributed to injection artifact (Fig. 3).

f3

Fig. 3

18F-FDG PET-CT performed in a 56-year-old woman with colorectal cancer. Some low grade FDG uptake is identified in non-enlarged right axillary nodes (yellow arrow) consistent with injection artifact

Imaging of metallic implants

The use of CT for attenuation correction negates the need for traditional transmission attenuation correction, reducing scanning time. There are however technical factors relating to the use of CT imaging for attenuation correction, which lead to artefacts when imaging metal [9]. The presence of metal implants in the body produces streak artifact on CT imaging and degrades image quality. When CT images are used for attenuation correction, the presence of metal results in over attenuation of PET activity in this region and can result in artifactual ‘hot spots.’ Metal prostheses, dental fillings, indwelling ports and breast expanders and sometimes contrast media are common causes of streak artifact secondary to high photon absorption and can cause attenuation correction artifacts [9]. In order to avoid false positives, particularly when imaging metallic implants careful attenuation should be paid to the nonattenuation corrected images, which do not produce this artifact.

Sites of physiological FDG uptake

Physiological uptake in a number of organs is readily recognized and rarely confused with malignancy. These include cerebral tissue, the urinary system, liver and spleen. Approximately 20% of administered activity is renally excreted in the 2 h post-injection resulting in intense radiotracer activity in the renal collecting systems, ureters and bladder [13]. In order to minimize the intensity of renal activity, patients are advised to void prior to imaging. Moderate physiological FDG uptake is noted in the liver, spleen, GI tract and salivary glands. Uptake in the cecum and right colon tends to be higher than in the remainder of the colon due to the presence of glucose-avid lymphocytes [14].

Other sites of physiological FDG activity can be confused with malignancy. Examples include activity within brown fat, adrenal activity, uterus and ovaries.

Brown fat

FDG uptake in hyper-metabolic brown adipose tissue is well recognized as a potential source of false positive in 18F-FDG PET-CT imaging. The incidence of FDG uptake in brown fat has been reported as between 2.5–4% [1516].

Hypermetabolic brown fat is more commonly identified in children than in adults and is more prevalent in females than in males. It occurs more frequently in patients with low body mass index and in cold weather [15].

Glucose accumulation within brown fat is increased by sympathetic stimulation as brown fat is innervated by the sympathetic nervous system. In view of this, administration of oral propranolol is advised by some authors as it has been shown to reduce the uptake of FDG by brown fat [17]. This is not performed at our institution; however, attempts are made to reduce FDG uptake in brown fat by maintaining a warm ambient temperature and providing patients with blankets during the uptake phase.

The typical distribution of brown fat in a bilateral symmetric pattern in the supraclavicular and neck regions is rarely confused with malignancy. In cases where hypermetabolic brown fat is seen to surround lymph nodes, the CT images should be separately evaluated to allow morphological assessment of the lymph nodes. The classical CT features of pathological replacement of lymph nodes should be sought, namely increased short axis diameter, loss of the fatty hilum and loss of the normal concavity of the lymph node. If the morphology of the lymph node is entirely normal, malignancy can be confidently excluded and the increased uptake attributed to brown fat [18].

Atypical brown fat in the mediastinum can be misinterpreted as nodal metastases and has been identified in the paratracheal, paraoesophageal, prevascular regions, along the pericardium and in the interatrial septum. Extramediastinal sites of brown fat uptake include the paravertebral regions, perinephric, perihepatic and subdiaphragmatic regions and in the intraatrial septum [16].

The absence of an anatomical lesion on CT imaging in areas of FDG uptake should raise the possibility of brown fat to the reader. Careful evaluation of the CT images must be performed to confirm the presence of adipose tissue in the anatomical region correlating to the increased FDG activity on 18F-FDG PET before this activity be attributed to brown fat.

An awareness of the possibility of brown fat in atypical locations is vital to avoid overstaging, and correlation with CT imaging increases reader confidence in differentiating brown fat from malignancy (Fig. 4).

f4

Fig. 4

18F-FDG PET-CT surveillance scan performed in a 36-year-old male with a history of seminoma. Symmetrical uptake is noted in the neck, supraclavicular fossa and paravertebral regions consistent with typical appearance of brown fat activity (black arrow). Brown fat uptake is also seen in the left supradiaphragmatic region and left paraoesophageal region (yellow arrow) (a). 18F-FDG PET-CT performed in a 48-year-old male with a history of colorectal cancer. Increased FDG uptake is noted within brown fat associated with lipomatous hypertrophy of the intra-atrial septum (b)

Uterine and ovarian uptake

In premenopausal women endometrial uptake of FDG varies cyclically and is increased both at ovulation and during the menstrual phase of the cycle with mean SUV values of 3.5–5 [19]. Endometrial uptake in postmenopausal women is abnormal and warrants further investigation; however benign explanations for increased FDG uptake include recent curettage, uterine fibroids and endometrial polyps [19].

Benign ovarian uptake of FDG in premenopausal women can be associated with ovulation. In postmenopausal women, ovarian uptake of FDG should be further investigated (Fig. 5).

f5

Fig. 5

18F-FDG PET-CT performed in a 42-year-old premenopausal female with breast cancer. She was scanned during menstruation. FDG uptake is noted within metastatic right axillary nodes (black arrow). Increased FDG uptake is also noted within the endometrial canal of the uterus (yellow arrow), which is thickened on CT, consistent with active menstruation (a). 18F-FDG PET-CT performed in the same 42-year-old woman at a different stage in her menstrual cycle showing resolution of the previously identified uterine uptake (yellow arrow) (b)

Adrenal uptake

18F-FDG PET imaging is commonly used for evaluation of adrenal masses in patients with diagnosed malignancies. Similarly incidental adrenal lesions are commonly identified on staging 18F-FDG PET-CT imaging. The positive predictive value of 18F-FDG PET-CT evaluation of adrenal lesions has been reported as high as 95% with a similarly high negative predictive value of 94% [20].

Causes of false-positive adrenal lesions include angiomyolipoma, adrenal hyperplasia and adrenal adenomas (up to 5%) [2124]. FDG activity greater than that of the liver is generally associated with malignancy; however benign lesions have been reported with greater activity than liver [21].

Evaluation of the CT component can provide additional diagnostic information with identification of HU attenuation values of <10 on noncontrast CT for adrenal adenomas or fat-containing myelolipomata [21].

Symmetrical intense FDG activity with no identifiable abnormality on CT is associated with benign physiological FDG uptake (Fig. 6).

f6 f6-b

Fig. 6

18F-FDG PET-CT performed in a 50-year-old woman with inflammatory breast cancer. Diffuse increased FDG uptake is noted within the right breast (yellow arrow) and in a right axillary node (black arrow), consistent with malignancy (a). Increased symmetrical uptake is also noted within both adrenal glands with no abnormal correlate on CT (yellow arrow) (b). Post-chemotherapy PET-CT performed 5 months later demonstrates resolution of the activity within the breast, increased uptake in the bone marrow consistent with post treatment effect (black arrow) and persistent increased uptake in the adrenal glands (yellow arrow), confirming benign physiological activity (c)

Thyroid uptake

Thyroid uptake is incidentally identified on 18F-FDG PET imaging with a frequency of almost 4%, with a diffuse uptake pattern in roughly half of cases and a focal pattern in the remainder [22]. The majority of diffuse uptake represents chronic thyroiditis, multinodular goiter or Graves’ disease, whereas focal uptake is associated with a risk of malignancy that ranges from 30.9–63.6% in published studies [2223]. Focal thyroid uptake requires further investigation with ultrasound and tissue biopsy.

Uptake in the gastrointestinal tract

The pattern of physiological uptake within the GI tract is highly variable. Low-grade linear uptake is likely related to smooth muscle activity and swallowed secretions. More focal increased uptake in the distal esophagus is sometimes seen with Barrett’s esophagus. In view of this, referral for OGD may be reasonable in cases of increased uptake in the distal esophagus [1424].

The typical pattern of FDG uptake in the stomach is of low-grade activity in a J-shaped configuration. Small bowel typically demonstrates mild heterogeneous uptake throughout. Common pitfalls of small bowel evaluation relate to spuriously high uptake in underdistened or overlapping loops of bowel [1425].

Within the colon, FDG uptake is highly variable, however can be quite avid particularly in the cecum, right colon and rectosigmoid regions. Focal areas of FDG activity within the colon that are of greater intensity than background liver uptake should raise the suspicion of a colonic neoplasm (Fig. 7) [2526].

f7

Fig. 7

18F-FDG PET-CT restaging scan performed in a 65-year-old female with a history of breast cancer. Incidental focal uptake is identified in the ascending colon where some abnormal thickening is seen on the CT component (yellow arrow). Colonoscopy confirmed the presence of a T3 adenocarcinoma

In a review of over 3,000 patients’ focal areas of abnormal FDG uptake within the gastrointestinal tract (GIT) were identified in 3% of cases of staging 18F-FDG PET-CT studies.

Incidental malignant lesions were identified in 19% of these patients with pre-malignant lesions including adenomas in 42% of the patients [27]. In view of this endoscopy referral is recommended in the absence of a clear benign correlate for focal areas of avid uptake on CT imaging.

Treatment-related causes of false-positive uptake

There are a number of conditions that can occur in patients undergoing treatment for cancer. When imaging these patients to assess for response, we often see these treatment-related conditions. It is important to recognize the imaging features to avoid misdiagnosis.

Thymus/thymic hyperplasia

Thymic hyperplasia post-chemotherapy is a well-described phenomenon. It is generally seen in children and young adults at a median of 12 months post chemotherapy [28]. The presence of increased FDG uptake in the anterior mediastinum can be attributed to thymic hyperplasia by identification of a triangular soft tissue density seen retrosternally on CT with a characteristic bilobed anatomical appearance [29]. In the presence of thymic hyperplasia, there is generally preservation of the normal shape of the gland despite an increase in size [30].

Superior mediastinal extension of thymic tissue is an anatomical variant that has been described in children and young adults (Fig. 8).

f8

Fig. 8

A 3.5-year-old boy with abdominal Burkitt’s lymphoma. Coronal 18F-FDG PET scan obtained 5 months after completion of treatment shows increased activity in the thymus in an inverted V configuration and in superior thymic extension (white arrow). Note physiologic activity within the right neck in the sternocleidomastoid muscle (a). Axial CT image from the same 18F-FDG PET-CT study performed 5 months after treatment shows a nodule (white arrow) anteromedial to the left brachiocephalic vein (b). Axial fusion image shows that the FDG activity in the superior mediastinum corresponds to this enlarged nodule anteromedial to left brachiocephalic vein (white arrow) (c). Axial fusion image shows increased activity in an enlarged thymus consistent with thymic hyperplasia (white arrow; standardized uptake value 3.0) of similar intensity to activity in superior mediastinum (d)

It presents as a soft tissue nodule anteromedial to the left brachiocephalic vein and represents a remnant of thymic tissue along the path of migration in fetal life. In patients with thymic hyperplasia, a superior mediastinal nodule in this location may represent accessory thymic tissue. An awareness of this physiological variant is necessary to prevent misdiagnosis [28].

G-CSF changes

Granulocyte colony-stimulating factor is a glycoprotein hormone that regulates proliferation and differentiation of granulocyte precursors. It is used to accelerate recovery from chemotherapy-related neutropaenia in cancer patients. Intense increased FDG uptake is commonly observed in the bone marrow and spleen following GCSF therapy; however the bone marrow response to GCSF can be differentiated from pathological infiltration by its intense homogeneous nature without focally increased areas of FDG uptake. Increased FDG uptake attributable to GCSF uptake rapidly decreases following completion of therapy and generally resolves within a month (Fig. 9).

f9

Fig. 9

18F-FDG PET-CT performed in a 46-year-old male post four cycles of chemotherapy for lymphoma and 2 weeks post administration of G-CSF. Note the diffuse homogeneous increased uptake throughout the bone marrow and the increased uptake in the spleen (yellow arrow)

Marked uptake in the bone marrow can also be seen following chemotherapy, reflecting marrow activation [3132].

Radiation pneumonitis

Inflammatory morphological changes in the radiation field post-irradiation of primary or metastatic lung tumor can result in false-positive diagnosis. Radiation pneumonitis typically occurs following high doses of external beam radiotherapy (>40 Gy). In the acute phase (1–8 weeks) radiation pneumonitis is characterized by ground-glass opacities and patchy consolidation. This can commonly lead to a misdiagnosis of infection. Chronic CT appearances of fibrosis and traction bronchiectasis in the radiation field allow correct interpretation of increased FDG uptake as radiation pneumonitis as opposed to disease recurrence [3334]. Other organs are also sensitive to radiation, and persistent uptake due to inflammatory change can persist for up to 1 year. It is important to elicit a history of radiation from the patient and to correlate the increased uptake with the CT findings to avoid missing a disease recurrence (Fig. 10).

f 10

Fig. 10

18F18-FDG PET-CT performed in a 52-year-old male with newly diagnosed esophageal carcinoma. Increased FDG uptake is identified within the esophagus (black arrow) and an upper abdominal lymph node (yellow arrow), consistent with malignancy (a). 18F18-FDG PET-CT performed 6 weeks post-completion of radiotherapy for esophageal carcinoma. Linear increased uptake is identified along the mediastinum in the radiation port (black arrow). This corresponds to areas of ground-glass change on CT (yellow arrow) consistent with acute radiation change (b)

Infection

Bone marrow suppression places chemotherapy patients at increased risk of infection.

Inflammatory cells such as neutrophils and activated macrophages at the site of infection or inflammation actively accumulate FDG [35].

In the post-therapy setting it has been reported that up to 40% of FDG uptake occurs in non-tumor tissue [12]. Infection is one of the most common causes of false-positive 18F-FDG PET-CT findings post-chemotherapy. Chemotherapy patients are susceptible to a wide variety of infections, including upper respiratory chest infections, pneumonia, colitis and cholecystitis. Reactivation of tuberculous infection can occur in immunocompromised patients post,chemotherapy, and correlation with CT imaging can prevent misdiagnosis in suspected cases.

Atypical infections such as cryptococcosis and pneumocystis can also present as false-positives on FDG imaging (Fig. 11) [36].

f 11

Fig. 11

18F-FDG PET-CT performed in a 57-year-old male 2 weeks following chemotherapy for lung cancer. Increased FDG uptake is noted within the cecum (black arrow). On CT there is some thickening of the cecal wall and stranding of the pericecal fat (yellow arrow) consistent with typhilits

Surgery and radiotherapy

There are inherent challenges in the interpretation of 18F-FDG PET-CT imaging in the postoperative patient. Non-tumor-related uptake of FDG is frequently identified in post-operative wound sites, at colostomy sites or at the site of post-radiation inflammatory change. 18F-FDG PET-CT imaging during the early postoperative/post-radiotherapy period may result in overstaging of patients because of non-neoplastic uptake of FDG [12]. Careful evaluation of the CT component in this setting is vital as CT imaging can provide valuable additional information regarding benign inflammatory conditions commonly encountered in the postoperative setting such as abscesses or wound infection. These conditions are often readily apparent on CT, particularly when oral and/or IV contrast CT is administered.

The reader should also bear in mind that avid uptake of FDG at postoperative/post radiotherapy sites may mask malignant FDG uptake in neighboring structures. In order to minimize non-tumoral uptake of FDG, it is advisable to allow at least 6 weeks post-surgery or completion of radiotherapy prior to performing staging 18F-FDG PET-CT [24].

Talc pleurodesis

Talc pleurodesis is a commonly performed procedure for the treatment of persistent pneumothorax or pleural effusion. The fibrotic/inflammatory reaction results in increased FDG uptake on 18F-FDG PET imaging with corresponding high-density areas of pleural thickening on CT. SUV values of between 2–16.3 have been seen years after the procedure [37].

When increased FDG uptake is indentified in the pleural space in a patient with a known history of pleurodesis, correlation with CT is recommended to detect pleural thickening of increased attenuation that suggests talc rather than tumor.

It is extremely important that a comprehensive history with relevant surgical interventions is available to the reader in order to ensure accurate diagnosis and staging (Fig. 12).

f 12

Fig. 12

18F-FDG PET-CT performed in a 69-year-old male with a history of non-Hodgkin’s lymphoma. The patient had a previous talc pleurodesis for a persistent left pleural effusion. Increased FDG activity is identified within the left pleura (black arrow). CT demonstrates a pleural effusion with high density material along the left pleural surface consistent with talc (yellow arrow)

Flare phenomenon

Bone healing is mediated by osteoblasts, and an early increase in osteoblast activity on successful treatment of metastatic disease has been described [38]. “Bone flare” refers to a disproportionate increase in bone lesion activity on isotope bone scan despite evidence of a therapeutic response to treatment in other lesions and has been well described in breast, prostate and lung tumors. ‘Flare phenomenon’ has also been described on 18F-FDG PET-CT in patients with lung and breast cancer who are receiving chemotherapy [39].

Differentiating between increased FDG uptake due to flare response and true disease progression may not be possible in the early post-treatment studies. While it is recognized that bone flare is a rare phenomenon, an increase in baseline skeletal activity and appearance of new bone lesions despite apparent response or stable disease elsewhere should be interpreted with caution to avoid erroneously suggesting progressive disease.

Osteonecrosis

Osteonecrosis or avascular necrosis has been well described as a complication of combination chemotherapy treatment, especially where it includes intermittent high-dose corticosteroids (e.g., lymphoma patients) [40]. Commonly encountered sites include the hip and less frequently the proximal humerus. Occasionally we can see a discrete entity known as jaw osteonecrosis. Patients receiving IV bisphosphonates for the management of bone metastases are at an increased risk of developing this [41]. The development of osteonecrosis in the mandible is frequently preceded by tooth extraction. Radiographic findings that may be visualized on CT include osteosclerosis, dense woven bone, thickened lamina dura and sub-periosteal bone deposition [42]. FDG uptake can be seen in areas of osteonecrosis (Fig. 13).

f 13

Fig. 13

18F-FDG PET-CT performed in a 46-year-old gentleman with a history of non-Hodgkin’s lymphoma. Increased FDG uptake is identified in the right proximal humerus (black arrow). CT of the area demonstrates a corresponding vague area of sclerosis (yellow arrow). Biopsy of the area yielded osteonecrosis with no evidence of metastatic disease

Insufficiency fractures

Pelvic insufficiency fractures have been described following irradiation for gynecological, colorectal, anal and prostate cancer. They commonly occur within 3–12 months post-radiation treatment, and osteoporosis is often a precipitating factor. FDG uptake in insufficiency fractures ranges from mild and diffuse to intense and heterogeneous. The maximum SUV values are variable with reported values of between 2.4–7.2 [43]. Differentiating insufficiency fractures from bone metastases can prove challenging; however they are often bilateral and occur in characteristic locations within the radiation field—sacral ala, pubic rami and iliac bones. Biopsy of insufficiency fractures can lead to irreparable damage and so careful correlation of 18F-FDG PET imaging with the CT component along with radiation history is vital for correct diagnosis. CT allows evaluation of the bone cortex and adjacent soft tissues, which can confirm the diagnosis of a pathological fracture or a metastatic deposit.

Follow-up of suspected insufficiency fractures demonstrates a reduction in FDG uptake over time (Fig. 14) [43].

f 14

Fig. 14

18F-FDG PET-CT performed in a 46-year-old female, 3 years post-chemo-radiation for cervical carcinoma. Low grade FDG uptake is identified in the left acetabulum and right pubic bone (black arrow). CT demonstrates pathological fractures in these areas consistent with insufficiency fractures (yellow arrow)

Sarcoidosis

Sarcoidosis is a chronic multisystem disorder characterized by non-caseating granulomas and derangement of normal tissue architecture [36]. Sarcoidosis has been reported in association with a variety of malignancies either synchronously or post-chemotherapy. Aggregation of inflammatory cells post-chemotherapy is associated with accumulation of FDG, and the intensity of FDG uptake may correlate with disease activity [36].

When suspected disease recurrence presents with signs and symptoms compatible with sarcoidosis (i.e., mediastinal and bihilar lymphadenopathy), this must be excluded by clinical, radiological and pathological correlation to prevent mistreatment (Fig. 15).

f 15

Fig. 15

18F-FDG PET-CT performed in a 67-year-old male for restaging of laryngeal carcinoma. Increased FDG uptake is noted in the left lower neck and left mediastinum (black arrow). CT demonstrates lymphadenopathy in these areas (yellow arrow), some of which are calcified. Biopsy of the left lower neck node confirmed sarcoidosis

FDG-PET negative tumors

There are a number of malignancies that can be FDG-PET negative. Examples include bronchoalveolar carcinoma and carcinoid tumors in the lung, renal cell carcinomas and hepatomas, mucinous tumors of the GIT and colon, and low grade lymphomas [34448]. Careful evaluation of the CT component of the study however will prevent a misdiagnosis (Fig. 16).

f 16

Fig. 16

18F-FDG PET-CT performed in a 52-year-old female with breast cancer and chronic hepatitis. On the CT component a hyper-enhancing mass is identified in segment 4 of the liver (yellow arrow). No increased FDG activity is identified in this area on the PET component. Biopsy of the mass confirmed the diagnosis of a hepatocellular carcinoma

Osteoblastic metastases

Bone metastases are diagnosed in up to 85% of patients with advanced breast cancer, leading to significant morbidity and mortality. Sclerotic bone metastases are commonly associated with breast carcinoma [49].18F-FDG PET imaging is superior to nuclear bone scan in detection of osteolytic breast metastases; however it commonly fails to diagnose osteoblastic or sclerotic metastases [50]. Review of bony windows on CT imaging allows identification of sclerotic metastases and ensures accurate staging of metastatic bone disease (Fig. 17).

f 17

Fig. 17

Staging 18F-FDG PET-CT performed in a 45-year-old female with newly diagnosed breast cancer. CT demonstrates multiple small sclerotic foci in the spine and pelvis (yellow arrow), consistent with bony metastases. These are FDG negative on the PET component of the study

Discussion/conclusion

18F-FDG PET imaging has dramatically changed cancer staging, and findings of restaging studies commonly effect changes in treatment protocols. 18F-FDG however is not tumor specific. As interpreting physicians we need to be aware of these false positives and false negatives. In this review we have outlined atypical physiological sites of FDG uptake along with common causes of FDG uptake in benign pathological conditions, many of which are treatment related. With 18F-FDG PET-CT we have the advantage of two imaging modalities. The PET component gives us functional information and the CT, anatomical data. We have discussed the importance of dual-modality imaging and correlation with CT imaging of the above conditions. Furthermore CT imaging provides important diagnostic information in evaluation of tumors that poorly concentrate FDG. In light of the increased reliance of 18F-FDG PET-CT for cancer staging, it is vital that radiologists and nuclear medicine physicians be aware of pitfalls in 18F-FDG PET-CT imaging and correlate PET and CT components to avoid misdiagnosis, overstaging of disease and unnecessary biopsies.

Other research papers related to the use of 18F-PET in management of cancer were published on this Scientific Web site:

State of the art in oncologic imaging of Lymphoma.

State of the art in oncologic imaging of Colorectal cancers.

State of the art in oncologic imaging of Prostate.

State of the art in oncologic imaging of lungs.

State of the art in oncologic imaging of breast.

Whole-body imaging as cancer screening tool; answering an unmet clinical need?

 

References

1.

Pauwels EK, Ribeiro MJ, Stoot JH et al (1998) FDG accumulation and tumor biology. Nucl Med Biol 25:317–322PubMedCrossRef

2.

Wahl RL (1996) Targeting glucose transporters for tumor imaging: “sweet” idea, “sour” result. J Nucl Med 37(6):1038–1041PubMed

3.

Kim BT, Kim Y, Lee KS, Yoon SB, Cheon EM, Kwon OJ, Rhee CH, Han J, Shin MH (1998) Localized form of bronchioalveolar carcinoma: FDG PET findings. AJR 170(4):935–939PubMed

4.

Hoh CK, Hawkins RA, Glaspy JA, Dahlbom M, Tse NY, Hoffman EJ, Schiepers C, Choi Y, Rege S, Nitzsche E (1993) Cancer detection with whole-body PET using 2-[18F]fluoro-2-deoxy-D-glucose. J Comput Assist Tomogr 17(4):582–589PubMedCrossRef

5.

Fenchel S, Grab D, Nuessle K, Kotzerke J, Rieber A, Kreienberg R, Brambs HJ, Reske SN (2002) Asymptomatic adnexal masses: correlation of FDG PET and histopathologic findings. Radiology 223(3):780–788PubMedCrossRef

6.

Shreve PD, Anzai Y, Wahl RL (1999) Pitfalls in oncologic diagnosis with FDG PET imaging: physiologic and benign variants. Radiographics 19(1):61–77, quiz 150–151PubMed

7.

Abouzied MM, Crawford ES, Nabi HA (2005) 18 F-FDG imaging: pitfalls and artifacts. J Nucl Med Technol 33(3):145–155PubMed

8.

Boellaard R, O’Doherty MJ, Weber WA, Mottaghy FM, Lonsdale MN, Stroobants SG, Oyen WJ, Kotzerke J, Hoekstra OS, Pruim J, Marsden PK, Tatsch K, Hoekstra CJ, Visser EP, Arends B, Verzijlbergen FJ, Zijlstra JM, Comans EF, Lammertsma AA, Paans AM, Willemsen AT, Beyer T, Bockisch A, Schaefer-Prokop C, Delbeke D, Baum RP, Chiti A, Krause BJ (2010) FDG PET and PET/CT: EANM procedure guidelines for tumour PET imaging: version 1.0. Eur J Nucl Med Mol Imaging 37(1):181–200PubMedCrossRef

9.

Sureshbabu W, Mawlawi O (2005) PET/CT imaging artifacts. J Nucl Med Technol 33(3):156–161, quiz 163–164PubMed

10.

Lin E, Alavi A (2009) PET and PET/CT: A Clinical Guide: 2nd Edn. Thieme New York p 145

11.

Hany TF, Heuberger J, von Schulthess GK (2003) Iatrogenic FDG foci in the lungs: a pitfall of PET image interpretation. Eur Radiol 13(9):2122–2127, Epub 2002 Oct 17PubMedCrossRef

12.

Kazama T, Faria SC, Varavithya V, Phongkitkarun S, Ito H, Macapinlac HA (2005) FDG PET in the evaluation of treatment for lymphoma: clinical usefulness and pitfalls. Radiographics 25(1):191–207PubMedCrossRef

13.

Swanson DP, Chilton HM, Thrall JH (1990) Pharmaceuticals in medical imaging. Macmillan, New York

14.

Prabhakar HB, Sahani DV, Fischman AJ, Mueller PR, Blake MA (2007) Bowel hot spots at PET-CT. Radiographics 27(1):145–159PubMedCrossRef

15.

Yeung HW, Grewal RK, Gonen M, Schöder H, Larson SM (2003) Patterns of (18)F-FDG uptake in adipose tissue and muscle: a potential source of false-positives for PET. J Nucl Med 44(11):1789–1796PubMed

16.

Truong MT, Erasmus JJ, Munden RF, Marom EM, Sabloff BS, Gladish GW, Podoloff DA, Macapinlac HA (2004) Focal FDG uptake in mediastinal brown fat mimicking malignancy: a potential pitfall resolved on PET/CT. Am J Roentgenol 183(4):1127–1132

17.

Söderlund V, Larsson SA, Jacobsson H (2007) Reduction of FDG uptake in brown adipose tissue in clinical patients by a single dose of propranolol. Eur J Nucl Med Mol Imaging 34(7):1018–1022PubMedCrossRef

18.

Sumi M, Ohki M, Nakamura T (2001) Comparison of sonography and CT for differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck. AJR 176(4):1019–1024PubMed

19.

Lerman H, Metser U, Grisaru D, Fishman A, Lievshitz G, Even-Sapir E (2004) Normal and abnormal 18 F-FDG endometrial and ovarian uptake in pre- and postmenopausal patients: assessment by PET/CT. J Nucl Med 45(2):266–271PubMed

20.

Lu Y, Xie D, Huang W, Gong H, Yu J (2010) 18 F-FDG PET/CT in the evaluation of adrenal masses in lung cancer patients. Neoplasma 57(2):129–134PubMedCrossRef

21.

Boland GW, Blake MA, Holalkere NS, Hahn PF (2009) PET/CT for the characterization of adrenal masses in patients with cancer: qualitative versus quantitative accuracy in 150 consecutive patients. AJR Am J Roentgenol 192(4):956–962PubMedCrossRef

22.

Chen W, Parsons M, Torigian DA, Zhuang H, Alavi A (2009) Evaluation of thyroid FDG uptake incidentally identified on FDG-PET/CT imaging. Nucl Med Commun 30(3):240–244PubMedCrossRef

23.

Choi JY, Lee KS, Kim HJ, Shim YM, Kwon OJ, Park K, Baek CH, Chung JH, Lee KH, Kim BT (2006) Focal thyroid lesions incidentally identified by integrated 18 F-FDG PET/CT: clinical significance and improved characterization. J Nucl Med 47(4):609–615PubMed

24.

Blake MA, Slattery J, Sahani DV, Kalra MK (2005) Practical issues in abdominal PET/CT. Appl Radiol 34(11):8–18

25.

Kei PL, Vikram R, Yeung HW, Stroehlein JR, Macapinlac HA (2010) Incidental finding of focal FDG uptake in the bowel during PET/CT: CT features and correlation with histopathologic results. AJR Am J Roentgenol 194(5):W401–W406PubMedCrossRef

26.

Pandit-Taskar N, Schöder H, Gonen M, Larson SM, Yeung HW (2004) Clinical significance of unexplained abnormal focal FDG uptake in the abdomen during whole-body PET. AJR Am J Roentgenol 183(4):1143–1147PubMed

27.

Kamel EM, Thumshirn M, Truninger K, Schiesser M, Fried M, Padberg B, Schneiter D, Stoeckli SJ, von Schulthess GK, Stumpe KD (2004) Significance of incidental 18 F-FDG accumulations in the gastrointestinal tract in PET/CT: correlation with endoscopic and histopathologic results. J Nucl Med 45(11):1804–1810PubMed

28.

Smith CS, Schöder H, Yeung HW (2007) Thymic extension in the superior mediastinum in patients with thymic hyperplasia: potential cause of false-positive findings on 18 F-FDG PET/CT. AJR Am J Roentgenol 188(6):1716–1721PubMedCrossRef

29.

Ferdinand B, Gupta P, Kramer EL (2004) Spectrum of thymic uptake at 18 F-FDG PET. Radiographics 24(6):1611–1616PubMedCrossRef

30.

Baron RL, Lee JK, Sagel SS, Levitt RG (1982) Computed tomography of the abnormal thymus. Radiology 142(1):127–134PubMed

31.

Hollinger EF, Alibazoglu H, Ali A, Green A, Lamonica G (1998) Hematopoietic cytokine-mediated FDG uptake simulates the appearance of diffuse metastatic disease on whole-body PET imaging. Clin Nucl Med 23(2):93–98PubMedCrossRef

32.

Kazama T, Swanston N, Podoloff DA, Macapinlac HA (2005) Effect of colony-stimulating factor and conventional- or high-dose chemotherapy on FDG uptake in bone marrow. Eur J Nucl Med Mol Imaging 32(12):1406–1411PubMedCrossRef

33.

Claude L, Pérol D, Ginestet C, Falchero L, Arpin D, Vincent M, Martel I, Hominal S, Cordier JF, Carrie C (2004) A prospective study on radiation pneumonitis following conformal radiation therapy in non-small-cell lung cancer: clinical and dosimetric factors analysis. Radiother Oncol 71(2):175–181PubMedCrossRef

34.

Frank A, Lefkowitz D, Jaeger S, Gobar L, Sunderland J, Gupta N, Scott W, Mailliard J, Lynch H, Bishop J et al (1995) Decision logic for retreatment of asymptomatic lung cancer recurrence based on positron emission tomography findings. Int J Radiat Oncol Biol Phys 32(5):1495–1512PubMedCrossRef

35.

Love C, Tomas MB, Tronco GG, Palestro CJ (2005) FDG PET of infection and inflammation. Radiographics 25(5):1357–1368PubMedCrossRef

36.

Chang JM, Lee HJ, Goo JM, Lee HY, Lee JJ, Chung JK, Im JG (2006) False positive and false negative FDG-PET scans in various thoracic diseases. Korean J Radiol 7(1):57–69PubMedCrossRef

37.

Kwek BH, Aquino SL, Fischman AJ (2004) Fluorodeoxyglucose positron emission tomography and CT after talc pleurodesis. Chest 125(6):2356–2360PubMedCrossRef

38.

Coleman RE, Mashiter G, Whitaker KB, Moss DW, Rubens RD, Fogelman I (1988) Bone scan flare predicts successful systemic therapy for bone metastases. J Nucl Med 29(8):1354–1359PubMed

39.

Krupitskaya Y, Eslamy HK, Nguyen DD, Kumar A, Wakelee HA (2009) Osteoblastic Bone Flare on F18-FDG PET in Non-small Cell Lung Cancer (NSCLC) Patients Receiving Bevacizumab in addition to standard Chemotherapy. J Thorac Oncol 4(3):429–431PubMedCrossRef

40.

Talamo G, Angtuaco E, Walker RC, Dong L, Miceli MH, Zangari M, Tricot G, Barlogie B, Anaissie E (2005) Avascular necrosis of femoral and/or humeral heads in multiple myeloma: results of a prospective study of patients treated with dexamethasone-based regimens and high-dose chemotherapy. J Clin Oncol 23(22):5217–5223PubMedCrossRef

41.

Catalano L, Del Vecchio S, Petruzziello F, Fonti R, Salvatore B, Martorelli C, Califano C, Caparrotti G, Segreto S, Pace L, Rotoli B (2007) Sestamibi and FDG-PET scans to support diagnosis of jaw osteonecrosis. Ann Hematol 86(6):415–423PubMedCrossRef

42.

Arce K, Assael LA, Weissman JL, Markiewicz MR (2009) MR imaging findings in bisphosphonate-related osteonecrosis of jaws. J Oral Maxillofac Surg 67(5 Suppl):75–84PubMedCrossRef

43.

Oh D, Huh SJ, Lee SJ, Kwon JW (2009) Variation in FDG uptake on PET in patients with radiation-induced pelvic insufficiency fractures: a review of 10 cases. Ann Nucl Med 23(6):511–516PubMedCrossRef

44.

Erasmus JJ, McAdams HP, Patz EF Jr, Coleman RE, Ahuja V, Goodman PC (1998) Evaluation of primary pulmonary carcinoid tumors using FDG PET. AJR Am J Roentgenol 170(5):1369–1373PubMed

45.

Kang DE, White RL Jr, Zuger JH, Sasser HC, Teigland CM (2004) Clinical use of fluorodeoxyglucose F 18 positron emission tomography for detection of renal cell carcinoma. J Urol 171(5):1806–1809PubMedCrossRef

46.

Khan MA, Combs CS, Brunt EM, Lowe VJ, Wolverson MK, Solomon H, Collins BT, Di Bisceglie AM (2000) Positron emission tomography scanning in the evaluation of hepatocellular carcinoma. J Hepatol 32(5):792–797PubMedCrossRef

47.

Berger KL, Nicholson SA, Dehdashti F, Siegel BA (2000) FDG PET evaluation of mucinous neoplasms: correlation of FDG uptake with histopathologic features. AJR Am J Roentgenol 174(4):1005–1008PubMed

48.

Jerusalem G, Beguin Y, Najjar F, Hustinx R, Fassotte MF, Rigo P, Fillet G (2001) Positron emission tomography (PET) with 18 F-fluorodeoxyglucose (18 F-FDG) for the staging of low-grade non-Hodgkin’s lymphoma (NHL). Ann Oncol 12(6):825–830PubMedCrossRef

49.

Tateishi U, Gamez C, Dawood S, Yeung HW, Cristofanilli M, Macapinlac HA (2008) Bone metastases in patients with metastatic breast cancer: morphologic and metabolic monitoring of response to systemic therapy with integrated PET/CT. Radiology 247(1):189–196PubMedCrossRef

50.

Huyge V, Garcia C, Vanderstappen A, Alexiou J, Gil T, Flamen P (2009) Progressive osteoblastic bone metastases in breast cancer negative on FDG-PET. Clin Nucl Med 34(7):417–420PubMedCrossRef

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Curator: Aviva Lev-Ari, PhD, RN

 

SOURCE: Time Magazine, April 1, 2013: How to Cure Cancer by Bill Saporito

Key argument: Now the Cure for Cancer is possible thanks to the following innovations in the Division of Labor of the research process among institution.

1.  New Cancer Dream Teams deliver better results faster, better understand the metabolic changes of pancreatic cells.

Team Leader: Dan Von Hoff – A five phase parallel process of the Cancer Research endeavor: One tumor researched by FIVE Labs in parallel

  • Penn surgeon, Jeffrey Drebin removes tissue from a cancerous pancreas. Tissue is carried to Hospital Lab where it is prepared for analysis and frozen for preservation.
  • a piece will go to Princeton for metabolomic profiling, amino acids, sugar glutamine and up to 300 metabolites.
  • a piece will go to John Hopkins for DNA analysis by sequence analysis
  • a piece will go to Translational Genomics for chromosome analysis
  • a piece will go to Salk Institute for a look at the stellate (star shape. tissue repair function, also plays a role in cancer) cells – gene expression analysis Lab

Joint Lab work: Superior to any research ever known.

2. Drug agents in development for therapy targeting the genetic mutations

  • reactivate the body’s immune system
  • cut off a tumor’s blood or energy supply
  • restart apoptosis

3. New Biomarkers

  • Allows to identify, target and track cancer cells – PI3K mutation One pathway – three women’s Cancers: Ovarian, endometrial, Breast CA.
  • Dream Team led by

– Dr. Gordon Mills of MD Anderson, PI3K pathway investigator

Teams Science include:

– Women’s cancer specialist from MGH

– Dana Farber (Harvard)

– Vanderbilt University

– Columbia University

– BIDMC

– Memorial Sloan Kettering

Dream Teams results are better than Big Pharma: 95% failure rate for new oncology drugs 50% of Phase III trials – don’t cut it to FDA approval.

Dream Teams will launch Trial as soon as geneticists and biochemists match mutation to drug compound.

Big Targets: Pancreas, Breast Cancer, Lung Cancer

 

Example: Human trial at FIVE institutions (28-person team) with TWO unapproved drugs from TWO companies with one year of discovery

PARP inhibitor from AstraZeneca was combined with PI3K inhibitor from Novartis to combat BRCA1 gene mutation that develops ovarian cancer and triple negative Breast Cancer. Two unapproved drugs are combined. Result was without precedent.

4. Design and built of a smart chip device to trap circulating tumor cells (CTCs) in a blood sample – early identification of metastasis

5. Better chances of Five-year Survival Rates

  • 1975-1977 – 49%
  • 1978-1989 – 56%
  • 2002 – 2008 – 68%

6. More Americans who have a History of Cancer are alive today than in the past

[including Cancer-free and in-treatment]

  • 2004 – 10.8 millions
  • 2008 – 12 millions
  • 2012 – 13.7 millions

7. There are 94 millions ex-smokers in the US – elevated risk for lung Cancer. 175,00 new lung cancers diagnosed every year. MD Anderson is developing a simple blood test for protein marker that could detect lung cancer earlier than it is found, test to be used in combination with diagnostic imaging and risk models

8. Probability of developing some type of Cancer over one’s lifetime:

  • Men – 1 in 2
  • Women – 1 in 3

9. Funding of Dream Team Science by Stand Up to Cancer ( SU2C) Hollywood investment in Cancer Research

10. Cancer Statistics in the US

  • 2013: 580,350 will die of Cancer, NCI figures and 1.7 millions will be diagnosed, numbers will grow as population ages (1.4 millions in 2006)
  • 2013L Leading Types of Cancer: Prostate, Breast, Lung &Bronchus (~250,000 each type), colon (~100,000)
  • Cost of Cancer in 2008: Medical – $77.4 Billion, lost productivity – $124 Billion

11. Research at John Hopkins is focused on studying the the enzymatic on/off switches of gene expression including mutated genes that produce cancer cells.

12. Memorial Sloan Kettering Cancer Center – extensive research on Epigenetics, New epigenetic drugs can shrink tumors. Complete remission is experienced by patients treated with drugs that nudges T Cells.

Cancer is a complexed disease.

 

 

 

 

 

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Personalized Medicine: Clinical Aspiration of Microarrays

Reporter, Writer: Stephen J. Williams, Ph.D.

 In this month’s Science, Mike May (at http://www.sciencemag.org/site/products/lst_20130215.xhtml) describes some of the challenges and successes in introducing microarray analysis to the clinical setting.  Traditionally used for investigational research, microarray is now being developed, customized and used for biomarker analysis, prognostic and predictive value, in a disease-specific manner.

Challenges in data interpretation

      In an interview with Seth Crosby, director of the Genome Technology Access Center at Washington University School of Medicine in St. Louis, “the biggest challenge” in moving microarray to the clinical setting is data interpretation.  The current technology makes it possible to evaluate expression of thousands of genes from a patient’s sample however as Crosby describes is assigning clinical relevance to the data.  For example Crosby explains that Washington University had validated a panel of 45 oncology genes by next generation sequencing and are using these genes to develop diagnostic tests to screen patient tumors for the purpose of determining a personalized therapeutic strategy. Seth Crosby noted it took “hundreds of Ph.D. and M.D. hours” to sift through the hundreds of papers to determine which genes were relevant to a specific cancer type. However, he notes, that once we better understand which changes in the patient’s genome are related to a specific disease we will be able to narrow down the list and be able to produce both economical and more disease-relevant microarrays.

Is this aberration pathogenic or not?

     Microarrays are becoming an invaluable tool in cytogenetics, as eluded by Andy Last, executive vice president of the genetic analysis business unit at Affymetrix.  Certain diseases like Down syndrome have well characterized chromosomal alterations like additions or deletions of parts or entire chromosomes.  According to Affymetrix, the most common use of microarrays is for determining copy number variation.  However according to James Clough, vice president of clinical and genomic services at Oxford Gene Technology, given the hundreds of syndromes associated with chromosomal rearrangements, the challenge will be to determine if a small chromosomal aberration has pathologic significance, given that microarray affords much higher diagnostic yield and speed of analysis than traditional microscopic techniques.  To address this challenge, Oxford Gene Technologies, PerkinElmer, Affymetrix, and Agilent all have custom designed microarrays to evaluate disease specific copy number and SNP (single nucleotide polymorphism) microarrays.  For example PerkinElmer designed OncoChip™ to evaluate copy number variation in more than 1.800 cancer genes.  Agilent makes microarrays that evaluates both copy number variation such as its CGH (comparative genomic hybridization) plus SNP microarrays.  Patricia Barco, product manager for cytogenetics at Agilent, notes these arrays can be used in prenatal and postnatal research and cancer, and “can be customized from more than 28 million probes in our library”.

Custom Tools and Software to Handle the Onslaught of Big Data

     There is a need for FDA approved diagnostic tools based on microarrays. Pathwork Diagnostic’s has one such tool (the Pathwork Tissue of Origin test), which uses 2,000 transcript markers and a proprietary computational algorithm to determine from expression analysis, the tissue of origin of a patient’s tumor.  Pathwork also provides a fast, custom turn-around analytical service for pathologists who encounter difficult to interpret samples.  Illumina provides the Infinium HumanCore BeadChip family of microarrays, which can determine genetic variations for purposes of biological tissue banking.  This system uses a set of over 300,000 SNP probes plus 240,000 exome-based markers.

     Tools have also been developed to validate microarray results.  A common validation strategy is the use of quantitative real-time PCR to verify the expression changes seen on the microarray.  Life Technologies developed the TaqMan OpenArray Real Time PCR plates, which have 3,072 wells and can be custom-formatted using their library of eight million validated TaqMan assays.

Making Sense of the Big Data: Bridging the Knowledge Gap using Bioinformatics

          The use of microarray has spurned industries devoted to developing the bioinformatics software to analyze the massive amounts of data and provide clinical significance.  For example companies such as Expression Analysis use their bioinformatics software to provide pathway analysis for microarray data in order to translate the data into the biology.  Using such strategies can also validate the design of microarrays for various diseases.

Foundation Medicine, Inc., a molecular information company, provides cancer genomics test solutions. It offers FoundationOne, an informative genomic profile to identify a patient’s individual molecular alterations and match them with relevant targeted therapies and clinical trials. The company’s product enables physicians to recommend treatment options for patients based on the molecular subtype of their cancer.

The Canadian Bioinformatics Workshops series recently offered a course on using bioinformatic approaches to analyze clinical data generated from microarray approaches (http://bioinformatics.ca/workshops/2012/bioinformatics-cancer-genomics-bicg).   The course objectives are described below:

Course Objectives

Cancer research has rapidly embraced high throughput technologies into its research, using various microarray, tissue array, and next generation sequencing platforms. The result has been a rapid increase in cancer data output and data types. Now more than ever, having the bioinformatic skills and knowledge of available bioinformatic resources specific to cancer is critical. The CBW will host a 5-day workshop covering the key bioinformatics concepts and tools required to analyze cancer genomic data sets. Participants will gain experience in genomic data visualization tools which will be applied throughout the development of the skills required to analyze cancer -omic data for gene expression, genome rearrangement, somatic mutations and copy number variation. The workshop will conclude with analyzing and conducting pathway analysis on the resultant cancer gene list and integration of clinical data.

Successful Examples of Clinical Ventures Integrating Bioinformatics in Cancer Treatment Decision –Making

The University of Pavia, Italy developed a fully integrated oncology bioinformatics workflow as described on their website and at the ESMO 2012 Congress meeting:

http://abstracts.webges.com/viewing/view.php?congress=esmo2012&congress_id=370&publication_id=2530

ESMO

ONCO-I2B2 PROJECT: A BIOINFORMATICS TOOL INTEGRATING –OMICS AND CLINICAL DATA TO SUPPORT TRANSLATIONAL RESEARCH

Abstract:

2530

Congress:

ESMO 2012

Type:

Abstract

Topic:

Translational research

Authors:

A. Zambelli, D. Segagni, V. Tibollo, A. Dagliati, A. Malovini, V. Fotia, S. Manera, R. Bellazzi; Pavia/IT

  • Body

The ONCO-i2b2 project, supported by the University of Pavia and the Fondazione Salvatore Maugeri (FSM), aims at supporting translational research in oncology and exploits the software solutions implemented by the Informatics for Integrating Biology and the Bedside (i2b2) research centre, an initiative funded by the NIH Roadmap National Centres for Biomedical Computing. The ONCO-i2b2 software is designed to integrate the i2b2 infrastructure with the FSM hospital information system and the Bruno Boerci Biobank, in order to provide well-characterized cancer specimens along with an accurate patients clinical data-base. The i2b2 infrastructure provides a web-based access to all the electronic medical records of cancer patients, and allow researchers analyzing the vast amount of biological and clinical information, relying on a user-friendly interface. Data coming from multiple sources are integrated and jointly queried.

In 2011 at AIOM Meeting we reported the preliminary experience of the ONCO-i2b2 project, now we’re able to present the up and running platform and the extended data set. Currently, more than 4400 specimens are stored and more than 600 of breast cancer patients give the consent for the use of specimens in the context of clinical research, in addition, more than 5000 histological reports are stored in order to integrate clinical data.

Within the ONCO-i2b2 project is possible to query and merge data regarding:

• Anonymous patient personal data;

• Diagnosis and therapy ICD9-CM subset from the hospital information system;

• Histological data (tumour SNOMED and TNM codes) and receptor profile testing (Her2, Ki67) from anatomic pathology database;

• Specimen molecular characteristics (DNA, RNA, blood, plasma and cancer tissues) from the Bruno Boerci Biobank management system.

The research infrastructure will be completed by the development of new set of components designed to enhance the ability of an i2b2 hive to utilize data generated by NGS technology, providing a mechanism to apply custom genomic annotations. The translational tool created at FSM is a concrete example regarding how the integration of different information from heterogeneous sources could bring scientific research closer to understand the nature of disease itself and to create novel diagnostics through handy interfaces.

Disclosure

All authors have declared no conflicts of interest.

NCI has under-taken a similar effort under the Recovery Act (the full text of the latest report is taken from their website http://www.cancer.gov/aboutnci/recovery/recoveryfunding/investmentreports/bioinformatics:

Cancer Bioinformatics: Recovery Act Investment Report

November 2009

Public Health Burden of Cancer

Cancer is the second leading cause of death in the United States after heart disease. In 2009, it is estimated that nearly 1.5 million new cases of invasive cancer will be diagnosed in this country and more than 560,000 people will die of the disease.

To learn more, visit:

Cancer Bioinformatics Program Overview

Over the past five years, NCI’s Center for Biomedical Informatics and Information Technology (CBIIT) has led the effort to develop and deploy the cancer Biomedical Informatics Grid® (caBIG) in partnership with the broader cancer community.  The caBIG network is designed to enable the integration and exchange of data among researchers in the laboratory and the clinic, simplify collaboration, and realize the potential of information-based (personalized) medicine in improving patient outcomes. caBIG has connected major components of the cancer community, including NCI-designated Cancer Centers, participating institutions of the NCI Community Cancer Centers Program (NCCCP), and numerous large-scale scientific endeavors, as well as basic, translational, and clinical researchers at public and private institutions across the United States and around the world.  Beyond cancer research, caBIG capabilities—infrastructure, standards, and tools—provide a prototype for linking other disease communities and catalyzing a new 21st-century biomedical ecosystem that unifies research and care. ARRA funding will allow NCI to accelerate the ongoing development of the Cancer Knowledge Cloud and Oncology Electronic Health Records (EHRs) initiatives, thereby providing for continued job creation in the areas of biomedical informatics development and application as well as healthcare delivery.

The caBIG Cancer Knowledge Cloud: Extending the Research Infrastructure

The Cancer Knowledge Cloud is a virtual biomedical capability that utilizes caBIG tools, infrastructure, and security frameworks to integrate distributed individual and organizational data, software applications, and computational capacity throughout the broad cancer research and treatment community. The Cancer Knowledge Cloud connects, integrates, and facilitates sharing of the diverse primary data generated through basic and clinical research and care delivery to enable personalized medicine. The cloud includes information generated through large-scale research projects such as The Cancer Genome Atlas (TCGA), the cancer Human Biobank (caHUB) tissue acquisition network, the NCI Functional Biology Consortium, the NCI Patient Characterization Center, and the NCI Preclinical Development Pipeline, academic and industry counterparts to these projects, and clinical observations (from entities such as the NCCCP) captured in oncology-extended Electronic Health Records.  Through the use of the caBIG Data Sharing and Security Framework, the Cloud will support appropriate sharing of information, supporting in silico hypothesis generation and testing, and enabling a learning healthcare system.

A caBIG-Based Rapid-Learning Healthcare System: Incorporating Oncology-Extended Electronic Healthcare Records (EHRs)

The 21st-century Cancer Knowledge Cloud will connect individuals, organizations, institutions, and their associated information within an information technology-enabled cycle of discovery, development, and clinical care—the paradigm of a rapid-learning healthcare system. This will transform these disconnected sectors into a system that is personalized, preventive, pre-emptive, and patient-participatory.  To be realized, this model requires the adoption of standards-based EHRs. Presently, however, no certified oncology-based EHR exists, and fewer than 3 percent of oncologists with outpatient-based practices utilize EHRs. caBIG has recently established a collaboration with the American Society of Clinical Oncology (ASCO) to develop an oncology-specific EHR (caEHR) specification based on open standards already in use in the oncology community that will utilize caBIG standards for interoperability. NCI will implement an open-source version of this specification to validate the specification and to provide a free alternative to sites that choose not to purchase a commercial system. The launch customer for the caEHR will be NCCCP participating sites. NCI will work with appropriate entities to provide a mechanism for certifying that caEHR implementations are consistent with the NCI/ASCO specification.

Bards Cancer Institute has another clinical bioinformatics program to support their clinical efforts:

Clinical Bioinformatics Program in Oncology at Barts Cancer Institute at Barts and the London School of Medicine

http://www.bci.qmul.ac.uk/cancer-bioinformatics

BCI HomeCancer Bioinformatics

Bards

Why we focus on Cancer Bioinformatics

Bioinformatics is a new interdisciplinary area involving biological, statistical and computational sciences. Bioinformatics will enable cancer researchers not only to manage, analyze, mine and understand the currently accumulated, valuable, high-throughput data, but also to integrate these in their current research programs. The need for bioinformatics will become ever more important as new technologies increase the already exponential rate at which cancer data are generated.

What we do

  • We work alongside clinical and basic scientists to support the cancer projects within BCI.  This is an ideal partnership between scientific experts, who know the research questions that will be relevant from a cancer biologist or clinician’s perspective, and bioinformatics experts, who know how to develop the proposed methods to provide answers.
  • We also conduct independent bioinformatics research, focusing on the development of computational and integrative methods, algorithms, databases and tools to tackle the analysis of the high volumes of cancer data.
  • We also are actively involved in the development of bioinformatics educational courses at BCI. Our courses offer a unique opportunity for biologists to gain a basic understanding in the use of bioinformatics methods to access and harness large complicated high-throughput data and uncover meaningful information that could be used to understand molecular mechanisms and develop novel targeted therapeutics/diagnostic tools.

Developing Criteria for Genomic Profiling in Lung Cancer:

A Report from U.S. Cancer Centers

In a report by Pao et. al., a group of clinicians organized a meeting to standardize some protocols for the integration of microarray and genomic data from lung cancer patients into the clinical setting.[1]  There has been ample evidence that adenocarcinomas could be classified into “clinically relevant molecular subsets” based on distinct genomic changes.  For example EGFR (epidermal growth factor receptor) exon 19 deletions and exon 21 point mutations predict sensitivity to tyrosine kinase inhibitors (TKIs) like gefitinib, whereas exon 20 insertions predict primary resistance[2].

However, as the authors note, “mutational profiling has not been widely accepted or adopted into practice in thoracic oncology”.  

     Therefore, a multi-institutional workshop was held in 2009 among participants from Massachusetts General Hospital (MGH) Cancer Center, Memorial Sloan-Kettering Cancer Center (MSKCC), the Dana-Farber/Bingham & Women’s Cancer Center (DF/BWCC), the M.D. Anderson Cancer Center (VICC), and the Vanderbilt-Ingram Cancer Center (VICC) to discuss their institutes molecular profiling programs with emphasis on:

·         Organization/workflow

·         Mutation detection technologies

·         Clinical protocols and reporting

·         Patient consent

In addition to the aforementioned challenges, the panel discussed further issues for developing improved science-driven criteria for determining targeted therapies including:

1)      Including pathologists into criteria development as pathology departments are usually the main repositories for specimens

2)      Developing integrated informatics systems

3)      Standardizing new target validation methodology across cancer centers

 References

1.            Pao W, Kris MG, Iafrate AJ, Ladanyi M, Janne PA, Wistuba, II, Miake-Lye R, Herbst RS, Carbone DP, Johnson BE et al: Integration of molecular profiling into the lung cancer clinic. Clinical cancer research : an official journal of the American Association for Cancer Research 2009, 15(17):5317-5322.

2.            Wu JY, Wu SG, Yang CH, Gow CH, Chang YL, Yu CJ, Shih JY, Yang PC: Lung cancer with epidermal growth factor receptor exon 20 mutations is associated with poor gefitinib treatment response. Clinical cancer research : an official journal of the American Association for Cancer Research 2008, 14(15):4877-4882.

Other posts on this website on Cancer and Genomics include:

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Progression in Bronchial Dysplasia

Larry H Bernstein, MD, FCAP

 

Genomic evidence of pre-invasive clonal expansion, dispersal and progression in bronchial dysplasia


F McCaughan, CP Pipinikas, SM Janes, PJ George, PH Rabbitts and PH Dear
MRC Laboratory of Molecular Biology, Cambridge, Centre for Respiratory Research, Royal Free and University College Medical School, London, University College London Hospitals, London, Leeds Institute of Molecular Medicine, St James’s University Hospital, Leeds, UK
J Pathol 2011; 224: 153–159   http://dx.doi.org/10.1002/path.2887
http://www.jpathol.com/Genomic evidence of pre-invasive clonal expansion, dispersal and progression in bronchial dysplasia
http://www.ncbi.nlm.nih.gov/pubmed/21506132
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3378694/

The term ‘field cancerization’ is used to describe an epithelial surface that has a propensity to develop cancerous lesions, and in the case of the

  • aerodigestive tract this is often as a result of chronic exposure to carcinogens in cigarette smoke.

The clinical endpoint is the development of multiple tumours,

  • either simultaneously or sequentially in the same epithelial surface.

The mechanisms underlying this process remain unclear; one possible explanation is that

  • the epithelium is colonized by a clonal population of cells that are at increased risk of progression to cancer.

We now address this possibility in a short case series, using individual genomic events as molecular biomarkers of clonality. In squamous lung cancer the most common genomic aberration is 3q amplification. We use a digital PCR technique to

  • assess the clonal relationships between
  • multiple biopsies in a longitudinal bronchoscopic study,
  • using amplicon boundaries as markers of clonality.

We demonstrate that clonality can readily be defined by these analyses and confirm that

  • field cancerization occurs at a pre-invasive stage and that
  • pre-invasive lesions and
  • subsequent cancers are clonally related.

We show that while the amplicon boundaries can be shared between different biopsies,

the degree of 3q amplification and the internal structure of the 3q amplicon varies from lesion to lesion. Finally, in this small cohort, the degree of 3q amplification corresponds to clinical progression.
Keywords: clonality; bronchial dysplasia; molecular copy-number counting
Conflict of interest: A patent for molecular copy-number counting has been applied for by the UK Medical Research Council. Paul Dear is named on the patent application..

The term ‘field cancerization’ was first coined many years ago and the potential underlying biological processes have been studied and discussed at length,

  • particularly in cancers of the aerodigestive tract .

Three possible mechanisms for field cancerization have been mooted in lung cancer.

  • an epithelial surface exposed to repeated insult, such as cigarette carcinogens,
    • could develop multiple separate dysplastic foci that
    • do not originate from a single clone but share similar genetic aberrations
      • as a result of the common carcinogenic insult.
    • In time, one or more of these foci may progress to cancer.
  • a mutant clone expands and migrates to colonize the epithelial surface,
    • without breaching the basement membrane, and
    • molecular divergence results in subclonal populations that may or may not progress.
  • In the third explanation an established cancer spreads to form multifocal clonal tumours.

In the past shared mutations (particularly of TP53 ) or patterns of loss of heterozygosity (LOH) have been the main biomarkers used

  • to infer the presence or absence of a clonal relationship between separate biopsies
  • from a single individual in lung cancer and pre-invasive bronchial dysplasia.

It could be argued that defining a specific shared mutation in TP53,

  • a gene with multiple different mutational hotspots,
  • with or without supportive LOH studies,
  • is more suggestive of clonality than LOH patterns alone.

multiple, anatomically distinct biopsies from an individual with widespread mild dysplasia

  • had a common mutation in TP53,
    • indicating epithelial colonization at a pre-invasive stage.

recently – 70 multifocal lung cancers from 30 individuals suggested,

  • on the basis of both LOH and TP53 mutational analysis,
  • in 77% of individuals the lesions were clonally related.

a digital PCR technique, microdissection molecular copy-number counting (μMCC), can provide detailed high-resolution information on

  • structural genomic events
  • in archived pre-invasive bronchial biopsies, in which
    • the amount of available tissue for analysis is significantly limited and the DNA is of poor quality.

We used this approach to show that 3q amplification is consistently observed in high-grade, but

  • not low-grade, bronchial dysplastic lesions, and that
  • the likely focus of this amplification is SOX2,
    • consistent with recent results from other groups.

This study was prompted by an observation that at very low resolution (2 Mb)

  • a high-grade lesion and
  • a subsequent cancer appeared to share amplicon boundaries.

Therefore, these reasearchers used ultra high-resolution analysis of

  • shared amplicon boundaries
  • to define clonal relationships between
  • microdissected biopsies taken from
  • anatomically distinct parts of the bronchial tree in the same individuals.

Discussion

Field cancerization in the bronchial tree is often described, both in clinical practice and in terms of molecular biomarkers, but the mechanism and natural history of this process remains unclear.  These data, using precisely delineated amplicon boundaries as genomic biomarkers, confirm that

  • clonal expansion and dispersal of cells occurs and that
  • subclonal populations emerge with varying molecular characteristics and clinical outcomes.

A consistent observation in the current cases is that

  • the amplitude of 3q amplification predicts which lesion is likely to progress; and further,
  • there is incremental 3q amplification in those lesions that do progress.

The progression of dysplasia to invasion is generally held to reflect ongoing selection of  clonally advantageous genetic events. However, the contribution of regional genomic events to neoplastic progression is a focus of some debate—whether

  • it is of pathogenic consequence or
  • an epiphenomenon reflecting genome instability.

3q amplification may be

  • selectively neutral or it may be
  • a critical stage in the development of squamous lung cancer.

In support of the latter, the almost uniform finding of 3q amplification in invasive squamous lung cancer

  • its selection in the progression to invasion
    • points to a significant and perhaps obligate role
    • in the pathogenesis of SQC.

Whether SOX2 is the main target of this amplification or one of a number of target oncogenes that are co-amplified remains unclear.

English: Bronchial anatomy detail of alveoli a...

English: Bronchial anatomy detail of alveoli and lung circulation. Français : Anatomie pulmonaire: détail des alvéoles et de la circulation pulmonaires . (Photo credit: Wikipedia)

copy neutral LOH cancer

copy neutral LOH cancer (Photo credit: Wikipedia)

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Genomics of Bronchial Epithelial Dysplasia

Curator: Larry H Bernstein, MD, FCAP

 

C. Walker, LJ Robertson, MW Myskow, N. Pendleton & G.R. Dixon
Clatterbridge Cancer Research Trust, J K Douglas Cancer Research Laboratory, Clatterbridge Hospital, & Broadgreen Hospital, Liverpool, UK.
Br. J. Cancer (1994). 70, 297-303
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2033485/53 expression in normal and dysplastic bronchial epithelium and in lung carcinomas 

Bronchial epithelial dysplasia is thought to be a premalignant stage in the evolution of lung cancers. Using the CM-1 polyclonal antibody, we have examined the expression of the p53 protein in a larger series of bronchial dysplasias (n = 60) than hitherto investigated. The p53 protein was detected in 14% of mild, 25% of moderate and 59% of severe dysplasias; increased p53 expression correlated with the severity of dysplasia. p53-positive dysplasias had greater PCNA indices than p53-negative dysplasias. p53 expression in dysplastic tissues was compared with that in two groups of histologically normal epithelium: 14 bronchial biopsies from non-cancer patients of which all but one were negative and 32 bronchial margins from resected carcinomas, of which 17 showed infrequent solitary cells with p53-positive nuclei in predominantly basal locations scattered throughout the epithelium. These results for resection margins were confirmed by use of a second antibody, DO-1. Sixty-nine per cent of the corresponding carcinomas were p53 positive, but in 15 cases the p53 reactivity differed from resection margins. No correlation between p53 expression and any of the clinicopathological characteristics of these tumours was found. This study supports the observation that abnormal p53 expression may be an early but not obligatory event in malignant transformation in lung.

It is now widely agreed that all lung cancers are derived from a common pluripotent stem cell capable of expressing a variety of phenotypes. Although the sequence of events in the histogenesis of lung cancer is unknown, bronchial epithelial dysplasia is thought to be a premalignant stage in the evolution of lung carcinomas. Multistep genetic changes, which include

  • activation of cellular proto-oncogenes and
  • inactivation of tumour-suppressor genes, are
    • associated with the development of human cancers and are
    • thought to accompany the morphological changes that precede malignancy.

Currently the most commonly identified genetic change in human cancers is mutation in the p53 gene, located at position 13 on the short arm of chromosome 17. This gene is

  • a tumour suppressor gene and
  • encodes a 53 kDa nuclear phosphoprotein
  • capable of binding to DNA and
  • acting as a transcriptional factor.

The wild-type p53 protein inhibits cell proliferation, and

  • loss of this activity leads to neoplastic transformation.

This protein has a

  • short cellular half-life and
  • is usually present in normal cells, under normal physiological conditions, in extremely small amounts,
  • making it undetectable by standard immunohistochemical techniques.

Many mutations of the p53 gene, principally in exons 5-8,

  • lead to a functional inactivation of the -gene and
  • a protein product unable to regulate transcription, ultimately
  • resulting in deregulation of cell growth.

Mutant p53 has

  • an extended cellular half-life
  • enabling immunohistochemical detection of
  • the accumulated mutant protein in cell nuclei.

Although not all mutations lead to protein accumulation, in many studies a correlation between the p53 protein detected immunocytochemically and p53 gene mutations has been found.
Investigation of p53 overexpression in premalignant tissues has led to the observations that

  • alterations in the p53 gene
  • arise as late events in the evolution of some cancers,
    • e.g. in gastric carcinomas, prostatic carcinomas or melanomas, whereas in others,
    • e.g. oral , gall bladder and oesophageal, malignancies, abnormal p53 expression is an early event.

In attempts to define the type and temporal sequence of somatic genetic changes that precede the onset of invasive lung cancer, recent studies have reported mutations and allelic deletions in the p53 gene in preinvasive bronchial lesions. Immunodetectable p53 has been found in a few cases of bronchial dysplasia et al., and Nuorva et al. (1993) have reported that p53 overexpression correlated with the severity of dysplasia in 17 cases of dysplastic epithelium from cancer bearing patients. Thus lesions in the p53 gene have been reported as possible early events in the development of lung cancers.

p53 score and grade of dysplasia

The system of p53 scoring used in these experiments permitted a semiquantitative comparison of the degree of p53 expression in the various tissues examined. With increasing severity of dysplasia there was not only an increase in the percentage of cases demonstrating p53 staining but also an increase in the staining intensity of positive cells and an increase in the proportions of these positive cells. Thus, higher grades of dysplasia were associated with higher p53 scores; the Spearman rank correlation coefficient for the whole table is 0.47 (P = <0.0001), and considering  just the dysplasia cases it is 0.37 (P = 0.002). Comparison of p53 expression between the various grades of dysplasia by use of p53 score  results in more significant P-values by the Mann-Whitney test than obtained with the Fisher-Irwin tests.

PCNA indices

For 39 cases of bronchial dysplasia, PCNA indices had been determined previously (Pendleton et al., 1993). p53-positive dysplasias had significantly greater PCNA indices than p53-negative dysplasias (Table IVa), indicating abnormal growth in these p53-positive biopsies

Bronchial carcinomas and resection margins

In previous studies, a series of bronchial carcinomas (Burnett et al., 1993) and their corresponding resection margins which contained histologically normal epithelium (Pendleton et al., 1993) had been collected prospectively following surgery. Using the CM-1 antibody, p53-positive nuclei were seen in 22/32 (69%) of the tumours and in histologically normal epithelium in 17/32 (53%) of the resection margins (Table V).  p53-positive cells in resection margins were predominantly basal, solitary and scattered throughout the epithelium (Figure 2a), and were less frequent than in tumour tissues (Figure 2b) or many samples of dysplastic epithelium. Many nuclei were weakly stained, but some showed a staining intensity similar to p53-positive tumour cells. Compared with dysplasias and tumour tissues the p53 scores of resection margins were low (Tables III and V), with only one case with a score of 3 and no higher scores. To confirm these results, sections of resection margins were stained with the monoclonal antibody DO-1; all of the cases positive for the CM-1 antibody were also DO-1 positive, but two cases (numbers 16 and 21) which were negative for CM-1 were clearly positive for DO-1.

Discussion

During the course of the preparation of this manuscript, it has been reported that

  • the p53 protein accumulates frequently in early bronchial neoplasia.

This study differs only in that biopsies, not resected tumours, were examined and all tissues were derived from a single treatment centre.  The results of all published studies (p53 expression has so far been investigated in a combined total of 23 mild, 31 moderate and 77 severe dysplasias) yields

  • 19% of the mild,
  • 28% of the moderate and
  • 63% of the severe dysplasias
    • found to be p53 positive.

In other similar studies investigating the expression of the p53 protein in premalignant lesions of lung and other tissues,

  • results were analysed by assessment of p53 positivity.

In this study, analysis was either

    1. by comparison of p53-positive and -negative groups or
    2. by use of a p53 scoring system similar to that described by Vojtesk et al. (1993).

The advantage of this scoring system is that it allows comparison of the degree of p53 expression between tissue groups.
The p53-positive group, equivalent to the positive group in other similar studies,

  • had a p53 score of two or more.

Cells with the p53 score for intensity of 1 were clearly p53 positive and were

  • found in tumours as well as in dysplasias and normal tissues.

Unlike other studies of preinvasive lung lesions,

  • PCNA indices for many of the dysplasias in this series had been determined.

The greater PCNA indices of the p53-positive group

  • indicates that p53-positive dysplasias contain higher proportions of cells in the proliferative phase of the cell cycle;

this suggests that p53-positive dysplasias

  • may have abnormalities in their growth control mechanisms.

It is possible that alterations in the p53 gene confer a growth advantage on these cells, leading to

  • expansion of p53-positive cells as severity of dysplasia increases.

A close relation between p53 overexpression and PCNA indices has also been observed in

  • pancreatic duct cell carcinomas,
  • hepatocellular carcinomas, and
  • gastric cancers.

In this study, p53 expression in dysplastic tissues was

  • compared with two groups of histologically normal epithelium.

All but one of the first group, taken from patients who did not have cancer at the time of biopsy, were negative. Comparison of p53 expression in this group with that in

  • dysplastic bronchial biopsies
    • showed a highly significant difference between these groups.

The second group of histologically normal epithelium analysed,

  • from the resection margins of bronchial carcinomas,
    • showed p53-positive cells in a high proportion of cases,
      • indicating differences in the normal bronchial epithelium of cancer and non-cancer patients.

p53 positivity in the normal mucosa of resection margins did not result in a measurable increase in proliferation, as indicated by PCNA indices. This may suggest that the mechanism whereby the p53 protein is elevated in normal mucosa differs from that in dysplasia. Whatever the mechanism to account for these p53-positive cells in normal bronchial mucosa, it seems that their presence, even if not associated with mutation in the p53 gene, indicates abnormalities that are not reflected in the histological appearance of these cells.

The number of p53-positive tumours in the series (69% overall and 68% for non-small-cell lung cancers) agreed well

  • with the incidence of p53 positivity for lung cancers reported in some studies
  • but was higher than that found in others.

Although the number of tumours in this series was small no correlation in p53 overexpression was found with any of the clnical characteristics of these tumours. This contrasts with reports of a relationship between p53 overexpression and

  • poor prognosis and shortened survival,
  • tumour grade  or lymph node involvement and
  • a greater incidence in squamous cell carcinomas compared with other types of lung carcinoma .

This study supports the observation that abnormal p53 expression is an early but not obligatory event in the evolution of lung cancers. Immunodetection of p53 overexpression in bronchial epithelium

    • may be a useful tool in the identification of those early lesions which may progress to malignancy.
Age-standardised death rates from Trachea, bro...

Age-standardised death rates from Trachea, bronchus, lung cancers by country (per 100,000 inhabitants). (Photo credit: Wikipedia)

 

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Personalized Medicine in NSCLC

Reviewer: Larry H Bernstein, MD, FCAP

Introduction

Early in the 21st century, gefitinib, an epi­dermal growth factor receptor (EGFRtyrosine kinase inhibitor became available  for the treatment of non-small cell lung can­cer (NSCLC). Over 80% of selected patients

  • EGFR mutation-positive patients, respond to gefitinib treatment;
  • most patients develop acquired resistance to gefitinib within a few years.
Recently, many studies have been performed to determine precisely how to select patients who will respond to gefitinib, the best timing for its administration, and how to avoid the development of acquired resistance as well as adverse drug effects.
Lung cancers are classified according to their his­tological type. Because each variant has different bio­logical and clinical properties, including response to treatment, a precise classification is essential to pro­vide appropriate therapy for individual patients. Lung cancer consists of two broad categories—non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

NSCLC  – 20%–40% RR to chemotherapy

  • ade­nocarcinoma (AC),  40%–50% ( most common form)
    • higher sensitivity to chemotherapy than SCC or LC
  • squamous cell carcinoma (SCC),  ∼30%
  •  large cell carcinoma (LCC). 10%
The majority of patients with SCLC are diagnosed with
  • advanced cancer with distant metastasis
  • high sensitivity to chemotherapy.
  • response rate (RR) for SCLC is reportedly 60%–80%
  • complete remission is observed in only 15%–20% of patients
The Potential of Personalized Medicine in Advanced NSCLC
Personalized medicine—
  • matching a patient’s unique molecular profile with an appropriate targeted therapy—
  • is transforming the diagnosis and treatment of non–small-cell lung cancer (NSCLC).

Through molecular diagnostics, tumor cells may be differentiated based on the presence or absence of

  • receptor proteins,
  • driver mutations, or
  • oncogenic fusion/rearrangements.

The convergence of advancing research in drug development and genetic sequencing has permitted the development of therapies specifically targeted to certain biomarkers, which may offer a differential clinical benefit.

Putting personalized medicine in NSCLC into practice
With the data on the prognostic and predictive biomarkers EGFR and ALK, biomarker testing is increasingly important in therapy decisions in NSCLC.1,2
Biomarker Testing in Advanced NSCLC: Evolution in Pathology Clinical Practice
http://www.medscape.com/infosite/letstest/article-3
Multidisciplinary Approaches in the Changing Landscape of Advanced NSCLC
http://www.medscape.com/infosite/letstest/article-4
Oncology Perspectives on Biomarker Testing
http://www.medscape.com/infosite/letstest/article-1

References
1. National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology™: Non-Small Cell Lung Cancer. Version 2.2012.
http://www.nccn.org/professionals/physician_gls/PDF/nscl.pdf.                   August 6, 2012.
2. Gazdar AF. Epidermal growth factor receptor inhibition in lung cancer: the evolving role of individualized therapy. Cancer Metastasis Rev. 2010;29(1):37-48.

Over the last decade, a growing number of biomarkers have been identified in NSCLC.3,4 To date, 2 of these molecular markers have been shown to have both prognostic and predictive value in patients with advanced NSCLC: epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements.5-8 Testing for these biomarkers may provide physicians with more information on which to base treatment decisions, and reflex testing may permit consideration of appropriate therapy from the outset of treatment.2,9,10

References:
Lovly CM, Carbone DP. Lung cancer in 2010: one size does not fit all. Nat Rev Clin Oncol. 2011;8(2):68-70.
Dacic S. Molecular diagnostics of lung carcinomas. Arch Pathol Lab Med. 2011;135(5):622-629.
Herbst RS, Heymach JV, Lippman SM. Lung cancer. N Engl J Med. 2008;359(13):1367-1380.
Quest Diagnostics. Lung Cancer Mutation Panel (EGFR, KRAS, ALK).                       Sept 17, 2012
http://questdiagnostics.com/hcp/intguide/jsp/showintguidepage.jsp?fn=Lung/TS_LungCancerMutation_Panel.htm.

Rosell R, Gervais R, Vergnenegre A, et al. Erlotinib versus chemotherapy (CT) in advanced non-small cell lung cancer (NSCLC) patients (p) with epidermal growth factor receptor (EGFR) mutations: interim results of the European Erlotinib Versus Chemotherapy (EURTAC) phase III randomized trial. Presented at: 2011 American Society of Clinical Oncology (ASCO) Annual Meeting, J Clin Oncol. 2011;29(suppl). Abstract 7503.                        Aug 6, 2012.                    http://www.asco.org/ASCOv2/Meetings/Abstracts?&vmview=abst_detail_view&confID=102&abstractID=78285.
Mok TS, Wu YL, Thongprasert S, et al. Gefitinib or carboplatin-paclitaxel in pulmonary adenocarcinoma. N Engl J Med. 2009;361(10):947-957.
Kwak EL, Bang YJ, Camidge DR, et al. Anaplastic lymphoma kinase inhibition in non–small-cell lung cancer. N Engl J Med. 2010;363(18):1693-1703.
National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology™: Non-Small Cell Lung Cancer. Version 2.2012.
http://www.nccn.org/professionals/physician_gls/PDF/nscl.pdf.                        Aug 6, 2012
College of American Pathologists (CAP)/International Association for the Study of Lung Cancer (IASLC)/Association for Molecular Pathology (AMP) expert panel. Lung cancer biomarkers guideline draft recommendations. http://capstaging.cap.org/apps/docs/membership/transformation/new/lung_public_comment_supporting_materials.pdf.      Aug 6, 2012.
Gazdar AF. Epidermal growth factor receptor inhibition in lung cancer: the evolving role of individualized therapy. Cancer Metastasis Rev. 2010;29(1):37-48.

 Background Studies
In 2002, gefitinib (ZD1839; AstraZeneca) , the first epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, became available as an innovative molecular-targeted drug for the treatment of unresectable NSCLC. Initially, many NSCLC patients were expected to respond to gefitinib because many solid tumors, including NSCLC, are known to overexpress EGFR, which has a role in tumor pro­liferation and is used as a biomarker to predict poor prognosis. Gefitinib was shown to have a dra­matic effect on a limited number of patients; but  it was ineffective in 70%–80% of patients with NSCLC. There have been reports of death caused by interstitial pneumonia (IP), one of the critical adverse drug reactions (ADRs) associated with gefitinib use. Therefore, there is a need for  predicting the effects of gefitinib, and criteria for select­ing patients who could be treated with gefitinib.
 In 2004, Lynch et al. and Paez et al. each pub­lished, on the same day, sensational reports in the New England Journal of Medicine and Science, identifying somatic mutations in the tyrosine kinase domain of the EGFR gene in patients with gefitinib-sensitive lung cancer, as compared with none of the patients who had no response. Therefore, screening for EGFR mutations in lung cancer showed potential for identifying patients who would respond to gefi­tinib therapy. It then was found that patients with EGFR mutations in the area of the gene cod­ing for the ATP-binding pocket of the tyrosine kinase domain responded to gefitinib. Consequently, the EGFR genotyping has been used to select patients who will respond to gefitinib. Other genetic mutations have also been reported as indicators of the response or resistance to gefitinib; for example, mutations of the KRAS gene are associated with primary resistance to gefitinib. Thus, screening of EGFR and KRAS is used to
  • predict the effects of gefi­tinib and
  • to select patients who will respond to gefitinib in the clinical setting.
Until now, the effects of gefitinib have been predicted only by genotyping factors, such as EGFR and KRAS mutations. However, Nakamura et al showed a relationship between the blood concentration of gefitinib and its clinical effects. In their study of 23 NSCLC patients with EGFR mutations, the ratio of the gefitinib concentration on day 8 to that on day 3 after the first administration of gefitinib (C8/C3) correlated with the progression-free survival (PFS) period. Patients with a higher C8/C3 ratio had a significantly lon­ger PFS (P = 0.0158, 95% confidence interval [CI]: 0.237–0.862), which  suggests the importance of the PK of gefitinib on its clinical outcome.   Chmielecki et al. concurrently reported that maintain­ing a high concentration of erlotinib, another EGFR tyrosine kinase inhibitor (EGFR-TKIs) with the same mechanism of action as gefitinib, could
  1. delay the establishment of drug-resistant tumor cells and
  2. decrease the proliferation rate of drug-resistant cells compared to
    • treatment using a lower concentration of erlotinib.
Pharmacogenetic profile
Initially, gefitinib was expected to induce a response in patients with tumors that overexpressed EGFR because it exerts its antineoplastic effects by com­petitively inhibiting the binding of ATP to the ATP-binding site of EGFR.  A number of studies contradict this hypothesis:
(1) while approxi­mately 40%–80% of NSCLC overexpress EGFR, only 10%–20% of NSCLC patients respond to gefi­tinib;5,6 and
(2) while EGFR overexpression is known to be more common in SCC than AC, gefitinib shows a higher antineoplastic effect on AC than on SCC, while other reports indicated no correlation between the expression levels of EGFR and clinical outcomes.
In 2004, somatic mutations were identified in the EGFR tyrosine kinase domain of patients with gefitinib-responsive lung cancer, as compared with no mutations in patients exhibiting no response, and the presence of an EGFR mutation was highly correlated with a good response to gefitinib.The conformational change of the EGFR ATP-binding site caused by genetic mutations constitutively acti­vates the EGFR downstream signaling pathway and increases the malignancy of cancer. Conversely, the conformational change of the ATP-binding site can also increase its affinity for gefitinib; therefore, gefi­tinib can inhibit the downstream signaling pathway more easily, strongly induces apoptosis, and reduces the proliferation of cancer cells.
Mutations in exons 18–21 of EGFR are predictive factors for the clinical efficacy of gefitinib;
  • deletions in exon 19 and missense mutations in exon 21 account for ∼90% of these mutations.

The detection of EGFR muta­tions in exons 19 and 21 is considered to be essential to predict the clinical efficacy of gefitinib.
Acquired resistance
All responders eventually develop resistance to gefitinib but in 2005, an EGFR mutation in exon 20, which substitutes methionine for threonine at amino acid position 790 (T790M), was reported to be one of the main causes of acquired resistance to gefitinib. The EGFR T790M vari­ant

  1. changes the structural conformation of the ATP-binding site, thereby
  2. increasing the affinity of ATP to EGFR, while
  3. the affinity of gefitinib to ATP is unchanged.

Screening methods for EGFR and KRAS mutations
The detection of EGFR and KRAS mutations has been usually achieved by sequencing DNA amplified from tumor tissues; however, sequencing techniques are too complex, time-consuming, and expensive.  The selection of an appropri­ate method to detect EGFR and KRAS mutations is essential to make an exact prediction of the efficacy of gefitinib in individual patients. Advances in diagnostics and treatments for NSCLC have led to better outcomes and higher standards of what outcomes are expected. These new understandings and treatments have raised multiple new questions and issues with regard to the decisions on the appropriate treatment of NSCLC patients.

  • Biomarkers are increasingly recognized and applied for guidance in diagnosis, prognosis and treatment decisions and evaluation.
  • Biologics and newer cancer treatments are enabling the possibility for new combined treatment modalities in earlier stage disease
  • Maintenance therapy has been shown to be useful, but optimal therapy choices before and after maintenance therapy need clarification
  • The importance of performance status on treatment decisions
  • Comparative effectiveness is becoming an expectation across all treatments and diseases, and will prove difficult to accomplish within the complexity of cancer diseases
NCCN Molecular Testing White Paper: Effectiveness, Efficiency, and Reimbursement
PF Engstrom, MG Bloom,GD Demetri, PG Febbo, et al.
Personalized medicine in oncology is maturing and evolving rapidly, and the use of molecular biomarkers in clinical decisionmaking is growing. This raises important issues regarding the safe, effective, and efficient deployment of molecular tests to guide appropriate care, specifically regarding laboratory-developed tests and companion diagnostics. In May 2011, NCCN assembled a work group composed of thought leaders from NCCN Member Institutions and other organizations to identify challenges and provide guidance regarding molecular testing in oncology and its corresponding utility. The NCCN Molecular Testing Work Group identified
challenges surrounding molecular testing, including health care provider knowledge, determining clinical utility, coding and billing for molecular tests, maintaining clinical and analytic validity of molecular tests, efficient use of specimens, and building clinical evidence. (JNCCN 2011;9[Suppl 6]:S1–S16)
Executive Summary
The FDA recently announced plans for oversight of laboratory-developed tests (LDTs) and released draft guidance regarding the development of companion diagnostics concurrently with therapeutics, both areas over which the FDA has regulatory authority. As recognized by the FDA, these types of diagnostic tests are used increasingly to directly inform treatment decisions, and this especially impacts patients with cancer and their oncologists. However, because of the increasing complexity of some LDTs and increasing commercial interest in oncology-related LDTs in general, the FDA is considering whether its policy of exercising “enforcement discretion”

for LDTs is still appropriate. To provide guidance regarding challenges of molecular testing to health care providers and other stakeholders, NCCN assembled a work group composed of thought leaders from NCCN Member Institutions and other organizations external to NCCN.  The NCCN Molecular Testing Work Group agreed to define molecular testing in oncology as

  • procedures designed to detect somatic or germline mutations in DNA and
  • changes in gene or protein expression that could impact the
    • diagnosis,
    • prognosis,
    • prediction, and
    • evaluation of therapy of patients with cancer.
Therefore, the discussion focused on molecular tests that predict outcomes for therapy.
Realizing the importance of personalized medicine in advanced NSCLC
E Topol, B Buehler, GS Ginsburg.       Medscape Molec Medicine
With the data on the prognostic and predictive biomarkers EGFR and ALK, biomarker testing is increasingly important in therapy decisions in NSCLC
http://www.nccn.org/professionals/physician_gls/PDF/nscl.pdf/
Lung Cancer in the Never Smoker Population: An Expert Interview With Dr. Nasser Hanna

Lung cancer in the never smoker population is a distinct disease entity with specific molecular changes, offering the potential for targeted therapy.
Experts And Viewpoint, Medscape Hematology-Oncology, December 2007

An Update on New and Emerging Therapies for NSCLC
Simon L. Ekman, MD, PhD; Fred R. Hirsch, MD, PhD
On completion of these readings participants will be thoroughly familiar with these issues:
  1. The influence of histologic types and genetic and molecular markers on choosing and personalizing therapy in patients with advanced NSCLC
  2. The role of the pathologist in properly classifying subtypes of NSCLC and reporting the presence of molecular markers in tumor samples
  3. Familiarize themselves with effective methods of obtaining adequate tissue samples from patients and recognize the importance of accurate pathologic assessment of NSCLC
The rapid developments in molecular biology have opened up new possibilities for individualized treatment of non-small cell lung cancer (NSCLC), and, in recent years, has mainly focused on the epidermal growth factor receptor (EGFR). A greater understanding of the molecular mechanisms behind
  • tumorigenesis and
  • the identification of new therapeutic targets
    • have sparked the development of novel agents
    • intended to improve the standard chemotherapy regimens for NSCLC.
Along with the advent of targeted therapy, identifying biomarkers to predict the subset of patients more likely to benefit from a specific targeted intervention has become increasingly important.
EGFR TYROSINE KINASE INHIBITORS 
tumor-associated mutations in the tyrosine kinase domain of EGFR have been associated with response to EGFR TKIs
The most common EGFR-sensitizing mutations encompass deletions in exon 19 and a point mutation at L858R in exon 21; together,
  • they account for approximately 85% of EGFR mutations in NSCLC.
  • Other EGFR mutations have been detected, particularly in exon 20.
    •  mutations identified in exon 20 have been linked to resistance to EGFR TKIsNon-Small Cell Lung Cancer: Biologic and Therapeutic Considerations for Personalized Management
      Taofeek K. Owonikoko, MD, PhD
What is the role and application of molecular profiling in the management of NSCLC?
It is essential to:
  1. Identify advances in the understanding of molecular biology and histologic profiling in the treatment of NSCLC
  2. Summarize clinical data supporting the use of tumor biomarkers as predictors of therapeutic efficacy of targeted agents in NSCLC
  3. Devise an individualized treatment plan for patients with advanced NSCLC based on a tumor’s molecular profile
  4. Identify methods for overcoming barriers to effective incorporation of molecular profiling for the management of NSCLC into clinical practice
Non-small cell lung cancer (NSCLC),the most common type of lung cancer, usually grows and spreads more slowly than small cell lung cancer.
The three common forms of NSCLC are:
  1. Adenocarcinomas are often found in an outer area of the lung.
  2. Squamous cell carcinomas are usually found in the center of the lung next to an air tube (bronchus).
  3. Large cell carcinomas occur in any part of the lung and tend to grow and spread faster than the other two types
Smoking causes most cases of lung cancer. The risk depends on the number of cigarettes you smoke every day and for how long you have smoked. Some people who do not smoke and have never smoked develop lung cancer.
Working with or near the following cancer-causing chemicals or materials can also increase your risk:
  • Asbestos
  • Chemicals such as uranium, beryllium, vinyl chloride, nickel chromates, coal products, mustard gas, chloromethyl ethers, gasoline, and diesel exhaust
  • Certain alloys, paints, pigments, and preservatives
  • Products using chloride and formaldehyde
Non-small cell lung c

ancer
(NSCLC) accounts for
  • approximately 85% of all lung cancers.
Lung cancer  may produce no symptoms until the disease is well advanced, so early recognition of symptoms may be beneficial to outcome.
At initial diagnosis,
  • 20% of patients have localized disease,
  • 25% of patients have regional metastasis, and
  • 55% of patients have distant spread of disease.
Revisiting Doublet Maintenance Chemo in Advanced NSCLC 
H. Jack West, MD
  • Pemetrexed Versus Pemetrexed and Carboplatin as Second-Line Chemotherapy In Advanced Non-Small-Cell Lung Cancer
Ardizzoni A, Tiseo M, Boni L, et al
J Clin Oncol. 2102;30:4501-4507
Historically, our second-line therapy has evolved into a strategy of pursuing single-agent therapies for patients with advanced non-small cell lung cancer (NSCLC) who have received prior chemotherapy. This approach was developed on the basis of benefits conferred by such established treatments as docetaxel, pemetrexed, and erlotinib — each well-tested as single agents — and evidence indicating a survival benefit in previously treated patients.
A study out of Italy by Ardizzoni and colleagues published in the Journal of Clinical Oncology directly compares carboplatin/pemetrexed with pemetrexed alone, and
  • it provides more evidence that our current approach of sequential singlet therapy remains appropriate.
This randomized phase 2 trial enrolled 239 patients with advanced NSCLC, initially of any histology, then later amended (September 2008) to enroll
  • only patients with non-squamous NSCLC because of mounting evidence that pemetrexed is not active in patients with the squamous subtype of advanced NSCLC.
Patients must have received prior chemotherapy (without restriction on regimen except that it could not include pemetrexed). Participants were randomly assigned 1:1 to receive pemetrexed at the standard dose of 500 mg/m2 IV every 21 days or the same chemotherapy with carboplatin at an area under the curve of 5, also IV every 21 days.
The primary endpoint for the trial was progression-free survival (PFS), and the trial was intended to have results pooled with a nearly identically designed trial that was done in The Netherlands. The Dutch trial compared pemetrexed with carboplatin/pemetrexed at the same dose and schedule. The vast majority of patients (97.5%) had a performance status of 0 or 1, and the median age was 64 years.
The Italian study found no evidence to support a benefit in efficacy from the more aggressive doublet regimen. Specifically,
  • median PFS was 3.6 months with pemetrexed alone vs 3.5 months with carboplatin/pemetrexed.
  • Response rate (RR) and median overall survival (OS) were also no better with the doublet regimen
      • RR 12.6% vs 12.5%, median OS 9.2 vs 8.8 months, for pemetrexed and carboplatin/pemetrexed.

Moreover, pooling the data from the Italian trial with the Dutch trial demonstrated no significant differences between the 2 strategies. Subgroup analysis showed that

  • the patients with squamous NSCLC had a superior median PFS of 3.2 months with the carboplatin doublet vs 2.0 months with pemetrexed alone.

Unfortunately, this only confirms that adding a second agent is beneficial for patients receiving an agent previously shown to be ineffective in that population.

Viewpoint
Putting it in the context of previous data, these results only provide further confirmation that more is not better.
  • combinations are associated with more toxicity than single-agent therapy, and
  • this is likely to be especially relevant in previously treated patients whose ability to tolerate ongoing therapy over time may be reduced.

It is critical to balance efficacy with tolerability to enable us to deliver the treatment over a prolonged period. We need to recognize the importance of pacing ourselves if our goal is to administer treatments in a palliative setting for an increasingly longer duration.

Epidermal growth factor receptor (EGFR) signal...

Epidermal growth factor receptor (EGFR) signaling pathway. (Photo credit: Wikipedia)

EGFR structure

EGFR structure (Photo credit: Wikipedia)

ATP synthase

ATP synthase (Photo credit: Ethan Hein)

Non-small cell carcinoma - FNA

Non-small cell carcinoma – FNA (Photo credit: Pulmonary Pathology)

Articles on NSCLC in Pharmaceutical Intelligence:
Key Sources:
  1. Realizing the importance of personalized medicine in advanced NSCLC
    E Topol, B Buehler, GS Ginsburg. 

    Medscape Molec Medicine The Potential of Personalized Medicine in Advanced NSCLC

    With the data on the prognostic and predictive biomarkers EGFR and ALK, biomarker testing is increasingly important in therapy decisions in NSCLC
  2. Revisiting Doublet Maintenance Chemo in Advanced NSCLC
    H. Jack West, MD     http://www.medscape.com/viewarticle/777367
    Pemetrexed Versus Pemetrexed and Carboplatin as Second-Line Chemotherapy In Advanced Non-Small-Cell Lung Cancer
    Ardizzoni A, Tiseo M, Boni L, et al
    J Clin Oncol. 2102;30:4501-4507
  3. Lung Cancer in the Never Smoker Population: An Expert Interview With Dr. Nasser Hanna
    Experts And Viewpoint, Medscape Hematology-Oncology, December 2007
  4. Non-Small Cell Lung Cancer: Biologic and Therapeutic Considerations for Personalized Management
    Taofeek K. Owonikoko, MD, PhD   August 24, 2011.   Medscape
  5. An Update on New and Emerging Therapies for NSCLC
    Simon L. Ekman, MD, PhD; Fred R. Hirsch, MD, PhD     Medscape
  6. Lovly CM, Carbone DP. Lung cancer in 2010: one size does not fit all. Nat Rev Clin Oncol. 2011;8(2):68-70.
  7. Dacic S. Molecular diagnostics of lung carcinomas. Arch Pathol Lab Med. 2011;135(5):622-629.

  8. Herbst RS, Heymach JV, Lippman SM. Lung cancer. N Engl J Med. 2008;359(13):1367-1380.
  9. Gazdar AF. Epidermal growth factor receptor inhibition in lung cancer: the evolving role of individualized therapy.

    Cancer Metastasis Rev. 2010;29:37-48.

  10. NCCN Oncology Insights Report on Non-Small Cell Lung Cancer 1.2010
  11.   Review of the Treatment of Non-Small Cell Lung Cancer with Gefitinib
    T Araki, H Yashima, K Shimizu, T Aomori
    Clinical Medicine Insights: Oncology 2012:6 407–421  http://dx.doi.org/10.4137/CMO.S7340

 

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State of the art in oncologic imaging of lungs.

Author-Writer: Dror Nir, PhD

 This is the second post in a series in which I will address the state of the art in oncologic imaging based on a review paper; Advances in oncologic imaging that provides updates on the latest approaches to imaging of 5 common cancers: breast, lung, prostate, colorectal cancers, and lymphoma. This paper is published at CA Cancer J Clin 2012. © 2012 American Cancer Society.

The paper gives a fair description of the use of imaging in interventional oncology based on literature review of more than 200 peer-reviewed publications.

In this post I summaries the chapter on lung cancer imaging.

Lung Cancer Imaging

“Lung cancer remains the most common cause of death from cancer worldwide, having resulted in 1.38 million deaths (18.2% of all cancer deaths) in 2008.48 It also represents the leading cause of death in smokers and the leading cause of cancer mortality in men and women in the United States. In 2012, it was estimated that 226,160 new cases of lung cancer would be diagnosed (accounting for about 14% of cancer diagnoses) and that lung cancer would cause 160,340 deaths (about 29% of cancer deaths in men and 26% of cancer deaths in women) in the United States.1 The 1-year relative survival rate for the disease increased from 35% to 43% from 1975 through 1979 to 2003 through 2006.49 The 5-year survival rate is 53% for disease that is localized when first detected, but only 15% of lung cancers are diagnosed at this early stage.”

For cancer with such poor survival rates removal of the primary lesion by surgery at an early-stage disease is the best option. The current perception in regards to lung cancr is that patients may have subclinical disease for years before presentation. It is also known that early lung cancer lesions; adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are slow-growing, doubling time which can exceed 2 years.52 But, since at present, no lung cancer early-detection biomarker is clinically available, the diagnosis of this disease is primarily based on symptoms, and detection often occurs after curative intervention and when it’s already too late – see: Update on biomarkers for the detection of lung cancer and also Diagnosing lung cancer in exhaled breath using gold nanoparticles. Until biomarker is found, the burden of screening for this disease is on imaging.

“AIS and MIA generally appear as a single peripheral ground-glass nodule on CT. A small solid component may be present if areas of alveolar collapse or fibroblastic proliferation are present,5051 but any solid component should raise concern for a more invasive lesion (Fig. 8). Growth over time on imaging can often be difficult to assess due to the long doubling time of these AIS and MIA, which can exceed 2 years.52 However, indicators other than growth, such as air bronchograms, increasing density, and pleural retraction within a ground-glass nodule are suggestive of AIS or MIA.

CT image shows a ground glass nodule, which is the typical appearance of AIS, in the right upper lobe.

CT image shows a ground glass nodule, which is the typical appearance of AIS, in the right upper lobe.

 

CT (A) demonstrated extensive consolidation with air bronchograms in the left upper lobe, which at surgical resection were found to represent adenocarcinoma of mixed subtype with predominate (70%) mucinous bronchioloalveolar subtype. PET imaging in the same patient (B) demonstrated uptake in the lingula higher than expected for bronchioloalveolar carcinoma and probably due to secondary inflammation/infection. CT (C) obtained 3 years after images (A) and (B) demonstrated biopsy-proven recurrent soft-tissue mass near surgical site. Fused FDG/PET images (D) demonstrate no uptake in the area. This finding is consistent with the decreased uptake usually seen in tumors of bronchioloalveolar histology (new terminology of MIA).

CT (A) demonstrated extensive consolidation with air bronchograms in the left upper lobe, which at surgical resection were found to represent adenocarcinoma of mixed subtype with predominate (70%) mucinous bronchioloalveolar subtype. PET imaging in the same patient (B) demonstrated uptake in the lingula higher than expected for bronchioloalveolar carcinoma and probably due to secondary inflammation/infection. CT (C) obtained 3 years after images (A) and (B) demonstrated biopsy-proven recurrent soft-tissue mass near surgical site. Fused FDG/PET images (D) demonstrate no uptake in the area. This finding is consistent with the decreased uptake usually seen in tumors of bronchioloalveolar histology (new terminology of MIA).

In August 2011 the results of the “National Lung Screening Trial “ which was funded by the National Cancer Institute (NCI) were published in NEJM; Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening. This randomized study results showed that with low-dose CT screening of high-risk persons, there was a significant reduction of 20% in the mortality rate from lung cancer as compared to chest radiographs screening.

Based on these results one can find the following information regarding Lung Cancer Screening on the NCI web-site:

Three screening tests have been studied to see if they decrease the risk of dying from lung cancer.

The following screening tests have been studied to see if they decrease the risk of dying from lung cancer:

  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • Sputum cytology: Sputum cytology is a procedure in which a sample of sputum (mucus that is coughed up from the lungs) is viewed under a microscope to check for cancer cells.
  • Low-dose spiral CT scan (LDCT scan): A procedure that uses low-dose radiation to make a series of very detailed pictures of areas inside the body. It uses an x-ray machine that scans the body in a spiral path. The pictures are made by a computer linked to the x-ray machine. This procedure is also called a low-dose helical CT scan.

Screening with low-dose spiral CT scans has been shown to decrease the risk of dying from lung cancer in heavy smokers.

A lung cancer screening trial studied people aged 55 years to 74 years who had smoked at least 1 pack of cigarettes per day for 30 years or more. Heavy smokers who had quit smoking within the past 15 years were also studied. The trial used chest x-rays or low-dose spiral CT scans (LDCT) scans to check for signs of lung cancer.

LDCT scans were better than chest x-rays at finding early-stage lung cancer. Screening with LDCT also decreased the risk of dying from lung cancer in current and former heavy smokers.

Guide is available for patients and doctors to learn more about the benefits and harms of low-dose helical CT screening for lung cancer.

Screening with chest x-rays or sputum cytology does not decrease the risk of dying from lung cancer.

Chest x-ray and sputum cytology are two screening tests that have been used to check for signs of lung cancer. Screening with chest x-ray, sputum cytology, or both of these tests does not decrease the risk of dying from lung cancer.

The authors of Advances in oncologic imaging found out that for pre-treatment staging and post treatment follow-up of lung cancer patients mainly involves CT (preferably contrast enhanced, FDG PET and PET/CT. “Integrated PET/CT has been found to be more accurate than PET alone, CT alone, or visual correlation of PET and CT for staging NSCLC (Non-small-cell lung carcinoma).59 “

The standard treatment of choice for localized disease remains surgical resection with or without chemo-radiation therapy (stage dependant). “The current recommendations for routine follow-up after complete resection of NSCLC are as follows: for 2 years following surgery a contrast-enhanced chest CT scan every 4 to 6 months and then yearly non-contrast chest CT scans.62 Detection of recurrence on CT is the primary goal in the initial years, and therefore, optimally, a contrast-enhanced scan should be obtained to evaluate the mediastinum. In subsequent years, when identifying an early second primary lung cancer becomes of more clinical importance, a non-contrast CT chest scan suffices to evaluate the lung parenchyma.

CT (A) of 78-year-old male who was status post–left lobe lobectomy and left upper lobe wedge resection shows recurrent nodule at the surgical resection site. Fused PET/CT (B) demonstrates increased [18F]FDG uptake in the corresponding nodule at the surgical resection site consistent with recurrent tumor.

CT (A) of 78-year-old male who was status post–left lobe lobectomy and left upper lobe wedge resection shows recurrent nodule at the surgical resection site. Fused PET/CT (B) demonstrates increased [18F]FDG uptake in the corresponding nodule at the surgical resection site consistent with recurrent tumor.

In patients undergoing chemotherapies: “ [18F]FDG PET response correlates with histologic response.63 [18F]FDG PET scan data can provide an early readout of response to chemotherapy in patients with advanced-stage lung cancer.64

In patients treated by recently developed “Targeted Therapies” such as Radiofrequency ablation (RFA) the authors found out that PET/CT is the preferred imaging modality for post treatment follow-up.

“ Most patients treated with pulmonary ablation will have had a pre-procedure CT or a fusion PET/CT scan, which allows more precise anatomic localization of abnormalities seen on PET. Generally, either CT or PET/CT is performed within a few weeks of the procedure to provide a new baseline to which future images can be compared to assess for changes in size, degree of enhancement or [18F]FDG avidity.67

CT (A) demonstrates new left upper lobe mass representing new primary NSCLC in a patient who had a status post–right pneumonectomy for a prior NSCLC. CT (B) obtained in the same patient 2 weeks after radiofrequency ablation (RFA) demonstrates the postablation density in the left upper lobe. Fused PET/CT (C) obtained 4 months after RFA demonstrates mild [18F]FDG uptake at RFA site in the left upper lobe consistent with posttreatment inflammation. Fused PET/CT (D) obtained 7 months after RFA demonstrates new focal [18F]FDG uptake at post-RFA-opacity consistent with recurrent tumor.

CT (A) demonstrates new left upper lobe mass representing new primary NSCLC in a patient who had a status post–right pneumonectomy for a prior NSCLC. CT (B) obtained in the same patient 2 weeks after radiofrequency ablation (RFA) demonstrates the postablation density in the left upper lobe. Fused PET/CT (C) obtained 4 months after RFA demonstrates mild [18F]FDG uptake at RFA site in the left upper lobe consistent with posttreatment inflammation. Fused PET/CT (D) obtained 7 months after RFA demonstrates new focal [18F]FDG uptake at post-RFA-opacity consistent with recurrent tumor.

Prostate Cancer Imaging

To be followed…

Other research papers related to the management of Lung cancer were published on this Scientific Web site:

Diagnosing lung cancer in exhaled breath using gold nanoparticles

Lung Cancer (NSCLC), drug administration and nanotechnology

Non-small Cell Lung Cancer drugs – where does the Future lie?

Comprehensive Genomic Characterization of Squamous Cell Lung Cancers

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