Multinational analysis of risk-reducing mastectomy and breast cancer mortality among women with a BRCA1/2 pathogenic variant

Risk-reducing mastectomy (RRM) is offered to women with a BRCA1 or BRCA2 pathogenic variant (PV). However, there are limited data on the impact on breast cancer mortality. A multinational analysis by the Hereditary Breast Cancer Clinical Study Group investigated this impact. In the BRCA1/2 PV registry 827 women undergoing RRM were matched (year of birth, gene, and country) to 827 women not undergoing RRM. After a mean follow-up of 6.3 years there were 20 incident breast cancers and two breast cancer deaths in the RRM group and 100 incident breast cancers and seven breast cancer deaths in the control group. The probability of dying of breast cancer within 15 years after RRM was 0.95%. The authors conclude that among women with a BRCA1/2 PV, RRM reduces the risk of breast cancer, and the probability of dying of breast cancer is low.