Purpose: The debate concerning poorer survival for patients with breast cancer (BC) carrying a BRCA1 germline mutation is unresolved, and requires additional data from population-based studies.
Patients and methods: We followed 232 women with invasive BC under age 46, ascertained prospectively through a French population-based BC registry and tested for BRCA1/2 mutations (median follow-up: 82 months). We compared tumour characteristics and survival rates between 21 BRCA1/2 deleterious mutation carriers and 211 non-carriers.
Results: As compared to sporadic tumours, BRCA1/2 tumours showed higher grade (P = 0.02), fewer ductal carcinoma in situ (P = 0.02), more frequent medullary histology (P = 0.02), more frequent negative oestrogen and progesterone receptors (P = 0.001 each). At 5 years, BC-specific survival, metastasis-free survival, ipsilateral recurrence-free survival and contralateral BC-free survival rates for BRCA1/2 mutation carriers were 95.0%, 94.7%, 100% and 90.0% respectively, compared with 89.6%, 78.2%, 88.8% and 94.4% respectively, for non-carriers (not significant). Rates for women carrying only a BRCA1 mutation were 93.3%, 93.3%, 100%, 86.7%, respectively. 76% of BRCA1/2 carriers received chemotherapy.
Conclusion: Despite unfavourable tumour features, we found no evidence for poorer short-term survival in BRCA1 mutation carriers compared to non-carriers in this prospective population-based cohort. The high rate of BRCA1 carriers who received chemotherapy for their BC should question the positive impact of this treatment, as suggested by preclinical studies showing increased chemosensitivity of BRCA1-associated tumours.