Comparison of Outcomes Between BRCA Pathogenic Variant Carriers Undergoing Breast-Conserving Surgery Versus Mastectomy.

Introduction: Although outcomes are similar following breast-conserving surgery (BCS) or mastectomy among sporadic breast cancer patients, data are mixed for women with a germline BRCA mutation. We sought to compare outcomes among a modern cohort of BRCA mutation carriers undergoing BCS versus mastectomy.

Methods: Women with a BRCA mutation and an index breast cancer from 2006-2015 were retrospectively identified from institutional databases. Factors, including date of genetic testing, clinicopathologic details, and treatment characteristics, were identified. Subsequent locoregional recurrence (LRR), distant recurrence, contralateral breast cancer (CBC), breast cancer-specific survival (BCSS), and overall survival (OS) events were compared between groups.

Results: A total of 395 BRCA mutation carriers with 424 cancers were identified. Surgical treatment included BCS for 99 cancers and mastectomy for 325 cancers. Patients choosing mastectomy were more likely to have bilateral breast cancer, be younger/premenopausal, and be aware of their genetic status before surgery, and were less likely to receive radiation therapy (p < 0.001). At 7.9 years median follow-up, LRR, distant recurrence, BCSS, and OS rates did not differ between groups. CBC occurred in 5 versus 0 women treated with unilateral versus bilateral surgery, respectively, resulting is a 10-year estimated CBC risk of 14% among unilateral breast surgery patients (p < 0.001).

Conclusions: With nearly 8 years follow-up, we report no difference in LRR, BCSS, and OS among BRCA mutation carriers who underwent BCS or mastectomy; however, we report a higher incidence of CBC among those undergoing unilateral breast surgery. These data support BCS as an option for BRCA mutation carriers willing to continue high-risk screening.