Long-term oncologic outcomes of unselected triple-negative breast cancer patients according to BRCA1/2 mutations

Abstract Triple-negative breast cancer (TNBC) patients are more likely to have BRCA1/2 mutations, with a prevalence rate of about 10–20%. Although several studies have analyzed the oncologic outcomes between BRCA1/2 carriers and non-carriers, the impact on breast cancer patients is still unclear. A retrospective review was performed to determine the differences in long-term outcomes of TNBC patients according to BRCA1/2 mutation status. A total of 953 TNBC patients who underwent primary breast cancer surgery from June 2008 to January 2016 were included. The oncologic outcomes were compared according to BRCA1/2 mutation status. Overall, 122 patients (12.8%) had BRCA1/2 mutations. The median follow-up duration was 80.9 months. There were no significant differences in distant metastasis-free survival and overall survival (P = 0.330 and 0.549, respectively) between BRCA1/2 carriers and non-carriers at 150 months. However, BRCA1/2 carrier cumulative recurrence rate and breast cancer-specific survival rate showed meaningful difference compared to non-carriers at 150 months (36.1% vs. 23.5%, 88.8% vs. 82.4%, P = 0.080 and 0.072, respectively). Cumulative contralateral breast cancer (CBC) incidence for BRCA1/2 carriers at 150 months was significantly higher than non-carriers (25.5% vs. 5.2%, P = 0.018). Among 29 patients with CBC recurrence, 24 patients (82.8%) had recurring TNBC type breast cancer and among the CBC recurrence patients, 19 patients (65.5%) resumed chemotherapy. In unselected TNBC patients with known BRCA1/2 mutations, we found significantly increased CBC recurrence in BRCA1/2 mutation carriers than non-carriers. While survival was not significantly different, more than 80% of CBC recurrence patients were TNBC.