Mammograms have been the mainstay of breast cancer screening for many years. The standard mammogram consists of four views which are taken as each breast is compressed from top to bottom and laterally. A radiologist interprets the mammogram by looking for a mass in the breast tissue. Breasts are composed of fat and glands.
Fat in a breast is very dark black and contrasts glandular tissue which is white. Dense breasts are composed of glandular tissue that can appear very white on a mammogram and can hide masses. Some breast masses are quite dense and contain calcium deposits that are more easily visible. Some types of cancer, often the lobular type, is often not as dense and can not always be seen within normal breast tissue. Therefore, mammograms are not without false negatives. We also know there are false positives, areas that look suspicious and need to be biopsied and cause much anxiety, but turn out to be benign.
Researchers and radiologists are looking for better tests: less false negatives and false positives, less discomfort for women, less risks, and less cost. The latest improvement in mammography is the 3D mammogram. With this technique, the breast tissue is visualized in "slices" that reduces overlapping tissue that can appear as a tumor because of superimposed images, and can demonstrate small tumors that were obscured by surrounding tissue. The result in studies that have been done demonstrate 17-34% less "call backs" for additional testing, and an increased breast cancer detection rate of as much as 50%. There was not found to be an increased in detection of DCIS with the 3D mammogram.
Although this new mammogram has improved detection rates, often finding cancers that are less than 10 mm, some cancers can be still be missed. At the recent North American Menopause Society meeting last week, attention was give to research being done on tests that target metabolically active tissue: the sestambi scan and MRI's. Molecular breast imaging has the potential of finding many more cancers than mammograms. An abbreviated MRI is being developed that will be much less expensive and more widely available. Stay tuned for further developments!
Plenary Symposium B: Advances in Breast Imaging, Dr. Emily F. Conant, M.D.
Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
North American Menopause Society Annual Meeting, 2017