Women who have inherited mutations in the BRCA1 or BRCA2 (BRCA1/2) genes have a substantially elevated risk of developing breast and ovarian cancer. For more than 10 years, researchers have studied whether preventive surgery (to remove breasts, ovaries, and/or fallopian tubes) can reduce the cancer and mortality risk in BRCA1/2 mutation carriers. This Issue Brief summarizes the results of the latest, largest, multinational study on the effects of preventive surgery in these women. The results are consistent with earlier studies and provide strong evidence for the use of preventive surgery as an effective approach to managing this genetic risk.