It has been established that women who carry a germline BRCA mutation face breast cancer risks of 60-70% in their lifetime. After an initial breast cancer diagnosis, these women face a high risk for contralateral breast cancer. Some women with BRCA mutations move forward with contralateral mastectomy when they develop their first breast cancer diagnosis (as part of their breast cancer treatment); however it remains unclear whether contralateral mastectomy reduced the breast cancer-related mortality in these women. Recently, Dr. Kelly Metcalfe published a study1 based on 390 women with stage I or II breast cancer and a BRCA mutation followed for up to 20 years from diagnosis. Of these women, 209 were treated with unilateral mastectomy compared to 181 treated with bilateral mastectomy. Results indicated that women with BRCA-associated breast cancer treated with bilateral mastectomy were 48% less likely to die of breast cancer within 20 years of diagnosis than women treated with unilateral mastectomy (even after controlling for age). This is among the largest and longest running studies to evaluate long-term survival of BRCA-associated breast cancers, comparing type of surgery at initial diagnosis. Study findings suggest that bilateral mastectomy should be discussed as an option for young women with a BRCA mutation and early stage breast cancer. However, despite the long follow-up and large sample size, further research is needed to confirm these findings given the small numbers of “events” (i.e., second breast cancers) in participants. Ultimately, emerging data on personalized chemotherapeutic and biologic treatments for BRCA-related breast cancers coupled with study findings suggest that women with newly-diagnosed breast cancer might benefit from the knowledge that they carry a BRCA mutation.
Metcalfe et al. 2014 BMJ. 2014 Feb 11;348:g226. PMID: 24519767