As we approach the beginning of Breast Cancer Awareness Month -- and the endless stream of pinkwashing that accompanies it -- the world is still reeling from Angelina Jolie's May 2013 decision to undergo what is termed "prophylactic mastectomy": the removal of her healthy breasts, based on her fear that she would later develop breast cancer. However, new research demonstrates that most women undergoing prophylactic mastectomies do so out of fear, rather than an understanding of their actual risk, adding to previous findings that as much as 80% of contralateral prophylactic mastectomies are misguided.
When Angelina Jolie revealed her decision to have two healthy breasts removed, public opinion -- and medical opinions -- were divided. Part of the controvers stemmed from the fact that Jolie had her surgery performed at a for-profit institution called Pink Lotus, and that she virtually advertised the services of this facility in her New York Times op-ed piece. However, much of the commentary also focused on some facts glossed over by the media, namely: that prophylactic mastectomy only removes about 95% of breast tissue, and that cancer has been known to develop in the remaining 5% -- indeed, individuals with BRCA1 mutations are more likely to develop many kinds of cancer, and researchers advise vigilance above all; that having a baby, particularly before age 30, and breast-feeding a baby for 24 months or more are two factors that significantly reduce a woman's risk of developing breast cancer; and that many lifestyle factors, including obesity, are well within a woman's control and can dramatically affect her chances of developing breast cancer.
Now, research published on September 17, 2013, in the Annals of Internal Medicine -- along with an editorial -- adds to the growing body of evidence demonstrating that most women undergoing prophylactic mastectomies greatly overestimate their risk of breast cancer. This overestimation has been particularly well documented in women who have had cancer in one breast. Pamela Portschy, MD, and Todd Tuttle, MD, MS, note, "Because the 10-year cumulative risk for CBC [contralateral breast cancer -- cancer in the previously unaffected second breast] is only 4% to 5%, CPM [contralateral prophylactic mastectomy] is not likely to improve breast cancer survival rates." They also warn that CPM "is an irreversible procedure and is not risk-free." A team of researchers led by Shoshana Rosenberg, SciD, MPH, report that most women they surveyed found that outcomes of CPM surgery were worse than they expected, with one-third reporting surprise at the number of procedures required and 42% noting "an altered sense of sexuality."
Unfortunately, it is not only patients who misunderstand statistics and overestimate risk. A survey performed roughly a decade ago and discussed by statistician Gerd Gigerenzer demonstrated that one-third of gynecologists did not understand the implications of a 25% risk reduction created by mammography screening. Rather than recognizing that 1 breast cancer death in 1000 screened women might be prevented, they erroneously believed that 250 deaths would be averted. Given this egregious innumeracy, researchers' advice that "early physician counseling is needed to provide women with accurate information regarding their true CBC risk" may be misguided. Perhaps women should meet with a statistician instead.