Locoregional treatments and ipsilateral breast cancer recurrence rates in BRCA1/2 mutation carriers

Abstract Background There is a paucity of data on the rates of ipsilateral breast tumor recurrence (IBTR) in BRCA1/2–associated breast cancer (BC). Scarcer yet is outcomes data in BRCA1/2 mutation carriers in the setting of newer mastectomy techniques such as skin-sparing (SSM) and nipple-sparing (NSM) mastectomies. Patients and methods Data was extracted from the medical records of BRCA1/2 carriers who were diagnosed with BC and treated at a single institution between 2006-2020. Data extracted included patient demographics, tumor characteristics, disease stage, surgical treatment, use of radiation therapy (RT) and disease outcome. Results Overall, 255 BC patients with BRCA1/2 germline mutations were identified. Of these, 128 (50.2%) underwent mastectomy (SSM or NSM in 82% of them): 76 (59.4%) without postmastectomy RT (non-PMRT) and 52 (40.6%) with PMRT; and 127 (49.8%) participants elected for breast conserving treatment (BCT). The non-PMRT group had earlier disease stage (82.3% were Tis and T1N0) compared to the PMRT and BCT groups (3.6% and 48.1%, respectively, p Conclusions BRCA1/2 mutation carriers treated with mastectomy without PMRT had higher rates of IBTR than those who underwent mastectomy and PMRT or BCT, despite earlier stage disease. The safety of SSM/NSM should be evaluated in a prospective trial.