Breast Cancer Prognosis in Young BRCA1/BRCA2 Mutation Carriers: A Retrospective Hospital-based Cohort Study.

Aim: Studies evaluating the prognostic impact of germline BRCA1/2 mutations (gBRCAm) in patients with breast cancer report conflicting results. Therefore, we aimed to investigate outcomes of patients with gBRCA mutations and early onset of breast cancer (<30 years) compared with those of noncarriers.

Materials And Methods: This retrospective study included 149 patients recruited between 2005 and 2019. The outcomes were overall survival (OS) and disease-free survival (DFS), which were defined as the time from the first diagnosis to death from any cause and the first recurrence, second cancer, or death from any cause, respectively. Key patient data, Kaplan-Meier plots, and outcomes were described according to the BRCA mutation status. Hazard ratios (HR) were calculated using the Cox proportional hazards model.

Results: Twenty-eight patients (28/149; 18.8 %) were gBRCAm carriers. The OS median follow-up was 8.2 years. OS was 89.3% [70.4-96.4] in carriers vs 99.2% [95% CI: 94.3-99.9] in non-carrier patients at 2 years; 85.2% [65.2-94.2] vs 93.0% [86.5-96.5] at 5 years, and 76.5% [54.7-88.8] vs 85.2% [75.7-91.2] at 10 years. There was no difference in OS between groups in multivariable analysis (HR = 1.90 [0.69-5.23], p = 0.22). The DFS median follow-up was 6.6 years. Similar results were observed for DFS (HR = 1.39 [0.63-3.08], p = 0.42).

Conclusion: In this large hospital-based cohort of patients with very early-onset breast cancer, we found no clear evidence that gBRCA1/2m significantly affects OS after adjusting for known prognostic factors.