New Law to Make Women Aware of Breast Density A New York state law that goes into effect Jan. 19 could impact up to half of all women who get their annual mammograms, according to Avice O’Connell, M.D., F.A.C.R., Director of Highland Breast Imaging and Women’s Imaging at the University of Rochester Medical Center. The law will require mammography providers to inform women in a letter if they have dense breast tissue following their annual mammograms. Up to 50 percent of women have dense breast tissue of some degree, Dr. O’Connell says. “Dense breast tissue itself does not lead to cancer,” she says. “But dense tissue does make cancer hard to detect with a mammogram alone.” On mammography images, a cancerous mass appears white, but it can be disguised by dense breast tissue surrounding it, which is also white. (The mammography image at the left depicts a breast with "extremely dense" tissue.) There are four categories of breast density. According to the new law, women whose breasts are deemed to be “extremely dense” or “heterogeneously dense” – the two highest levels of density – will be notified. The letter will also suggest women talk with their doctors about their personal risk for breast cancer and other screening options that might be necessary. One of the most important breast cancer risk factors is family history. Based on an assessment of a woman’s personal risk, her physician may recommend that she have supplemental testing, such as ultrasound screening.* "An ultrasound gives us a different view of the breast tissue,” Dr. O’Connell says. “The drawback is we will find many small, solid masses that will need to be biopsied or followed, and at least 90 percent of the time, they will turn out to be benign. “However, for a woman whose breast cancer is not found on a mammogram but is detected in an ultrasound, it is worth it.” Breast density is one of many risk factors for breast cancer, but its specific effect is still being discussed. Women with dense breasts who are not at an increased risk of breast cancer due to family history and other factors may choose not to have further testing beyond a mammogram. *The law does not require insurance to cover screening breast ultrasounds, but most of the major insurers have indicated they will cover the additional screening with a physician’s referral.