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State of the art in oncologic imaging of breast.

Author-Writer: Dror Nir, PhD

In the coming posts 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 breast cancer imaging.

Breast Cancer Imaging

As a start the authors describes the evolution in the ACS imaging guidelines for breast cancer screening. Most interesting to learn is how age limits are changing. The most recent: “In 2010, the Society of Breast Imaging and the Breast Imaging Commission of the ACS issued recommendations for breast cancer screening to provide guidance in light of the controversies and emerging technologies.5 These recommendations were based on multiple prospective randomized trials as well as population-based experience.

Recommendations for screening with non-mammographic imaging are based not on evidence showing mortality reduction but largely on surrogate indicators, i.e., tumor size and nodal status, suggesting improved survival compared with women who are not screened.” I have referred to these guidelines in my recent post: Not applying evidence-based medicine drives up the costs of screening for breast-cancer in the USA.

As long as imaging interpretation is based mainly on observations related to lesion morphology:

“The imaging characteristics of malignant lesions are nonspecific and usually do not allow a definitive diagnosis. When a biopsy is recommended based on mammography, it has a 25% to 45% likelihood of resulting in a diagnosis of carcinoma.11 Similar positive predictive values are reported for biopsies recommended based on MRI.”

It is worthwhile noting that these results do not reflect purely the specificity of the imaging device but rather the specificity of the whole workflow; i.e imaging, biopsy and histopathology. All imaging techniques have false negatives: Mammography screening of general population misses approximately 20% of the cancers. This rate increases as breast density increases. MRI is not applied to general population. When applied to highly suspicious cases MRI misses ~10% of the invasive cancers. Although ultrasound has proven to be useful in detecting cancer especially in women with dense breasts: Automated Breast Ultrasound System (‘ABUS’) for full breast scanning: The beginning of structuring a solution for an acute need! Based on the literature reviewed by the authors of this paper they do not recommend routine sonography for these women.

For women with locally advanced breast cancer (Fig. 2) who undergo neoadjuvant therapy before breast surgery, the authors recommends post-treatment staging using MRI, which has been found to predict complete response with sensitivity above 60% and specificity as high as 90%.26

Same is recommended for women who have undergone lumpectomy if the surgical margins are positive. As post therapy follow-up, a new baseline mammogram of the treated breast is recommended followed by annual mammography.

In regards to emerging technology the following are discussed: Mammographic tomosynthesis – see also Improving Mammography-based imaging for better treatment planning

Contrast-enhanced digital mammography – “involves the injection of iodinated contrast material, as is done for computed tomography (CT); this enables hypervascular lesions to be seen with modified mammography technology, potentially providing the same information obtained through MRI. Little has been published on the clinical application of this technology, but diagnostic accuracy better than that of mammography and approaching that of MRI has been reported.31, 32”

MR choline spectroscopy – has been shown to improve the positive predictive value of breast MRI and may be useful in reducing the number of lesions that require biopsy (Fig. 4).33 Studies of spectroscopy have reported sensitivities of 70% to 100% and specificities of 67% to 100% in the detection of breast cancer. Decreasing choline concentrations may also be a useful indication of tumor response to treatment before any change in tumor volume can be detected.34, 35 Technical factors have limited the use of spectroscopy to lesions 1 cm in size or larger.”

Diffusion-weighted MRI (DW-MRI) – “adding DW-MRI data to other imaging characteristics of lesions on breast MRI may increase the positive predictive value of the examination, in turn decreasing the number of benign lesions requiring biopsy for diagnosis.” See also Imaging: seeing or imagining? (Part 2).

Ultrasound-elastography – “Ultrasound elastography has been reported to differentiate benign from malignant breast lesions with sensitivities of 78% to 100% and specificities of 21% to 98%.39 When added to other US techniques, it may improve radiologists’ performance in distinguishing malignant breast lesions.”

Positron emission tomography (PET) – “alone or combined with CT, allows noninvasive, quantitative assessment of biochemical and functional processes at the molecular level in the body. It is most often performed with the radiolabeled glucose analogue [18F] fluorodeoxyglucose ([18F]FDG) to detect the elevated glucose metabolism that is a hallmark of cancer. In breast cancer, its utility depends on the pretest probability for advanced disease, and thus the clinical stage.” The authors found that the use of [18F] FDG PET to patients with stage I and II disease is “limited”. Specifically, they claim that it is not sufficiently accurate for axillary nodal staging in this subset of patients.40 The did find enough evidence to recommend the use of FDG PET in patients with advanced disease: “where it accurately defines disease extent,41 and frequently eliminates the need for other imaging tests, and provides an early readout of treatment response as well as prognostic information.”

Combined PET/MRI is mentioned as a promising technology for predicting response to therapy “but this remains to be proven”.

Positron emission mammography (PEM) – “adapts full-body PET imaging to the breast. In a multicenter study, the interpretation of PEM in conjunction with mammographic and clinical findings yielded a sensitivity of 91% and a specificity of 93% for breast cancer.47 “. However, the authors mention that its use for screening (applying to healthy women) has been criticized because of the need to administer a radioactive tracer.

Lung Cancer Imaging

To be followed…

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

The unfortunate ending of the Tower of Babel construction project and its effect on modern imaging-based cancer patients’ management

 Automated Breast Ultrasound System (‘ABUS’) for full breast scanning: The beginning of structuring a solution for an acute need!

Introducing smart-imaging into radiologists’ daily practice.

Will Bio-Tech make Medical Imaging redundant?

Improving Mammography-based imaging for better treatment planning

Not applying evidence-based medicine drives up the costs of screening for breast-cancer in the USA.

New Imaging device bears a promise for better quality control of breast-cancer lumpectomies – considering the cost impact

Harnessing Personalized Medicine for Cancer Management, Prospects of Prevention and Cure: Opinions of Cancer Scientific Leaders @ http://pharmaceuticalintelligence.com

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

What could transform an underdog into a winner?

Mechanism involved in Breast Cancer Cell Growth: Function in Early Detection & Treatment

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A Strategy to Handle the Most Aggressive Breast Cancer: Triple-negative Tumors

Optical Coherent Tomography – emerging technology in cancer patient management

Breakthrough Technique Images Breast Tumors in 3-D With Great Clarity, Reduced Radiation

Closing the Mammography gap

Imaging: seeing or imagining? (Part 1)

Imaging: seeing or imagining? (Part 2)