Women who develop breast cancer but knew they carried the breast cancer (BRCA) gene before they were diagnosed are much more likely to survive the disease than those who find out they are carriers after the fact, according to a new study by Prof. Ephrat Levy-Lahad of Jerusalem’s Shaare Zedek Medical Center.Specifically, 94% of women with breast cancer who knew they were carriers in advance did not die of any cause within five years, compared to 78% of women who found out only after they became affected. Moreover, the study found that there were big differences in terms of morbidity: More than half of the women who knew they were carriers did not need chemotherapy after being diagnosed with breast cancer. In contrast, 80% of those who found out they were carriers after diagnosis had to undergo chemo.Finally, known carriers tended to be diagnosed at earlier stages and by magnetic resonance imaging.The findings of the study, which specifically targeted women who knew they were carriers but chose not to remove their breasts before a cancer diagnosis, were published earlier this month in the peer-reviewed journal JAMA Oncology published by the American Medical Association.According to Levy-Lahad, Ashkenazi Jews have a high rate of BRCA 1 and 2.In 2014, she helped carry out an extensive study that led the Health Ministry to put screening for the BRCA gene into the health basket.“Beginning just this past January, every Ashkenazi woman can be tested through her health fund for the common mutations,” Levy-Lahad told The Jerusalem Post. She said those who are identified as carriers can have surveillance imaging for early detection or prevention.The main way to prevent breast cancer is to have a bilateral mastectomy – the surgical removal of both breasts. However, in Israel, no more than a sixth of known carriers choose to have this surgery. Worldwide, the numbers are not too different: No more than 50% of women choose to have their breasts removed, even in the Netherlands and the United States, where there are high rates of bilateral mastectomy.Levy-Lahad said that this is likely because of the psychological impact of such a surgery and the effect that it has on a woman’s body image.In the recent study, of the 105 BRCA pathogenic variant carriers diagnosed with breast cancer, 83% were Ashkenazi Jews. Of these, 42 (40%) were aware of their genotype before diagnosis, and 63 (60%) only after diagnosis.Levy-Lahad said she was surprised to learn that two-thirds of known carriers who were diagnosed with breast cancer had the bilateral mastectomy.“They don’t want to take the risk anymore, so they have both breasts removed,” she said. “The women who knew they could get cancer, when they get a first diagnosis, choose to have a bilateral mastectomy to protect themselves from a second cancer.”Levy-Lahad said that to her knowledge, “this is the first report to document a possible survival advantage for presymptomatic identification of BRCA carrier status in carriers who decline risk-reducing bilateral mastectomy.”The research was funded by the Breast Cancer Research Foundation in New York.