This is from the National Breast Cancer Coalition. Basically, they found that surgery on the healthy breast once a woman is found with breast cancer only reduces the risk of cancer from 0.7% to 0.04%, but that women often choose the surgery anyway. And that MRI of the opposite breast in such women has shown no overall survival benefit.
"Many women who are diagnosed with breast cancer in one breast fear that they are at increased risk of getting cancer in their other breast. Actually, the risk of that happening is, on average, 0.7% per year. In recent years, more and more radiologists are doing MRI screenings of the healthy breast in diagnosed women. Is there any benefit of using MRI to look at a woman’s healthy breast when she has been diagnosed with breast cancer? What are the benefits and risks?
"In his presentation, Dr. Tuttle showed that the expanded use of breast MRI among newly diagnosed patients is one of the main factors behind the doubling of contralateral prophylactic mastectomies (removing of the opposite, non-affected breast before breast cancer is found in that breast). Although prophylatic surgery reduced the risk of cancer development in the opposite breast by 95%, it is important to remember that the annual risk was small to begin with. That means that prophylatic surgery reduced the risk from 0.7% to 0.04%. Dr. Tuttle noted that there was no proven survival benefit from such aggressive surgery, but many patients still opted for it.
"In multiple prior studies, researchers found that MRI screening of the opposite breast at the time of initial diagnosis led to a large proportion of women undergoing unnecessary biopsies. Prior research has also shown no overall survival benefit from contralateral prophylactic mastectomies. We are also concerned that prophylactic mastectomies create complications that can delay recommended chemotherapy or radiation. NBCC’s analyses points out that while existing guidelines recommend MRI screening for high-risk women (positive BRCA 1 or 2 mutation), there is no proof that vigilant surveillance and screening save lives.
"No studies have shown that MRI reduces a woman’s risk of dying from breast cancer."