Prophylactic Irradiation to the Contralateral Breast for BRCA Mutation Carriers Undergoing Treatment for Breast Cancer

Women with BRCA germline mutations face a very high risk of developing breast cancer during their lives. It was shown that for carrier patients, breast conservation, comprising of lumpectomy followed by whole breast radiation, was not associated with increased risk of ipsilateral breast cancer recurrence as compared with non carriers (10-15% over 10 years), especially if they also underwent prophylactic oophorectomy. Yet their risk of subsequent contralateral breast cancer was significantly increased, reported as high as 25-30% over 10 years and 40% over 15 years, as compared to 3% and 7% respectively in non carriers. The reduction in ipsilateral disease was attributed to radiation of the affected breast. We propose that for breast cancer patients with BRCA germline mutation that choose to have breast-conserving therapy and refuse prophylactic contralateral mastectomy, prophylactic radiation to the contralateral breast may reduce the rate of subsequent contralateral breast cancer and offer an option for risk reduction.