Spotlight on Breast Imaging
RSNA goers today received a thorough briefing on key mammography topics on Sunday as experts addressed imaging challenges and outlined research demonstrating mammography's role in early detection and reduced mortality.
Debbie Monticello outlined anatomical challenges to achieving optimal mammograms. Tumors can present in the areas least expected, says Monticello. Breast tissue, and malignancies, appears to a greater extent than visible upon gross exam. Visualization of the retromammary space on the mammogram indicates that the tech has mobilized the breast forward. Monticello also shared statistics stressing the utility of mammography for patients with dense breasts. DCIS is nearly always asymptomatic and present as microcalcifications in 90 percent of patients. Microcalcifications can be visualized on the mammograms of women with dense breasts. Contrast-enhanced MRI is well-suited to analyze areas of neovascularity typical of malignant tumors. The downside of MRI is its relatively low sensitivity. Finally, lymph nodes are the most important prognostic indicator in breast cancer. Although imaging can not define whether or not a node is positive for cancer, sentinel node mapping is essential for prognosis and treatment.
Stephen Feig, MD, outlined six randomized clinical trials that link screening mammography with a reduction in mortality, while stressing that such trials underestimate the benefits. "The average woman diagnosed with invasive breast cancer today is 39 percent less likely to die from it than her counterpart in the early 1980s," states Feig. Daniel Kopans, MD, professor of radiology, HMS and director, breast imaging at Mass General Hospital pointed to the October 2005 paper published in New England Journal of Medicine that used computer modeling to attribute a 28 to 65 percent mortality reduction to screening mammography. In addition to mortality reductions, screening mammography is associated with a downstaging of the disease - with more women diagnosed at early, more curable stages.
Some studies have shown that the benefits of screening mammography aren't universal and vary with technical quality and interpretation. The radiologist can evaluate technical quality at the viewbox.  Positioning is particularly critical as the percentage of missed cancers increases with poor positioning. Other variable elements that affect the final product include compression, exposure, viewing condition, contrast and sharpness. Finally, Feig pointed out that breast imagers can profit with current screening reimbursement with efficient practices including batch reading, automatic reporting and use of an assistant to load studies.
Mammography remains the established gold standard for breast cancer screening, but a quick tour of the show floor proves that vendors are exploring new imaging technologies such as breast tomosynthesis to further boost its benefits.