Outcomes after breast cancer in an ethnically diverse cohort of high-risk patients: Differences in survival based on BRCA1/BRCA2 mutation status

Abstract

21116 Background: Most studies of hereditary breast cancer report that BRCA1 associated tumors are characterized by high grade and hormone receptor negativity, while those associated with BRCA2 are more similar to sporadic cases. Several groups have demonstrated that BRCA1 mutations, but not BRCA2 mutations, are associated with reduced survival in women with breast cancer. These studies have primarily included women of European and Ashkenazi Jewish heritage. No study to date has assessed outcomes in an ethnically diverse cohort of high-risk individuals. Methods: High-risk individuals were identified through the University of Chicago Cancer Risk Clinic (UCCRC). Clinicopathologic data was collected on all patients with breast cancer who had undergone genetic testing and consented to inclusion in research protocols. Recurrence-free survival (RFS) and overall survival (OS) for BRCA1, BRCA2 and non-carriers was compared using the log-rank test. Hazard ratios (HR) and 95% Confidence Intervals (95% CI) were calculated from Cox proportional hazard models. Results: 280 patients from 258 families were studied. 67 were BRCA1 mutation positive, 36 were BRCA2 positive and 177 were non-carriers. 65% of patients were non-Hispanic non-Jewish whites, 15% African American, 15% Ashkanazi Jewish, 3% Hispanic and 2% Asian. At a median follow up of 5 years, 40 patients had relapsed and 22 had died. HRs (95% CI) for RFS of the BRCA1 and BRCA2 carriers relative to non-carriers were 1.6 (0.77–3.33) and 1.3 (0.55–3.09) respectively, when adjusted for year at diagnosis. The adjusted HRs (95% CI) for OS for the BRCA1 and BRCA2 carriers relative to non-carriers were 1.82 (0.48–3.02) and 0.67 (0.15–3.04), respectively. Conclusions: In this study of an ethnically diverse cohort of high-risk individuals, BRCA1 mutation carriers had a poorer outcome as compared to those with BRCA2 mutations or those without identifiable mutations in either gene, although this difference was not statistically significant. This observation is consistent with previous studies of women of predominantly Ashkenzi Jewish and European ancestry. This study was funded by the Falk Medical Research Trust, the Breast Cancer Research Foundation and the Entertainment Industry Fund. No significant financial relationships to disclose.