Prevalence of BRCA1 mutations and responses to neoadjuvant chemotherapy among BRCA1 carriers and non-carriers with triple-negative breast cancer

Background: The frequency of BRCA1 germline mutations among Chinese women with triple-negative breast cancer is unclear, and the association between BRCA1 mutations and the response to neoadjuvant chemotherapy in women with triple-negative breast cancer has not been determined.

Patients and methods: Nine hundred and fifty-six triple-negative breast cancer patients were treated at our institute between 2003 and 2012; we tested the BRCA1/2 mutations for 956 patients and 953 patients in this cohort, respectively. Among the 956 patients, 652 patients received neoadjuvant chemotherapy.

Results: In this cohort, 7.1% (68/956) and 2.3% (22/953) of patients carried a BRCA1 or BRCA2 mutation, respectively. The BRCA1/2 mutation rates were 10.5% and 3.0% among the patients who were diagnosed at or before the age of 50 in this cohort, respectively. The pCR (pathologic complete response) rate was 31.6% in the 652 patients who received neoadjuvant chemotherapy. BRCA1 carriers had a significantly higher pCR rate than non-carriers (BRCA1 carriers versus non-carriers, 53.8% versus 29.7%, P < 0.001). Among women treated with anthracycline with or without taxane regimens, the pCR rate was 57.1% for BRCA1 carriers, 29.0% for non-carriers (P < 0.001); among women treated with taxane regimens, the pCR rate was 40.0% for BRCA1 carriers, 32.9% for non-carriers (P = 0.73). At a median follow-up of 43 months, the recurrence-free survival was similar between BRCA1 carriers and non-carriers among the 947 patients of this study (adjusted hazard ratio = 0.92; 95% confidence interval: 0.45-1.90; P = 0.82).

Conclusions: Chinese women with triple-negative breast cancer who are diagnosed at or before age of 50 are candidates for BRCA1 genetic testing. Among triple-negative breast cancer patients, BRCA1 carriers are more likely to respond to neoadjuvant anthracycline-based regimens than are non-carriers.