Outcomes of HER2-positive nonmetastatic breast cancer patients with or without deleterious BRCA mutations after trastuzumab treatment.

Abstract

e12550 Background: Human epidermal growth factor receptor (HER2) overexpression or amplification occurs in 20–25% of all breast cancers and is associated with an aggressive form of the disease with reduced disease-free survival (DFS) and overall survival (OS). However, the outcome of patients with HER2+ tumor and BRCA mutation is poorly described. The purpose of this analysis was to analyze the clinical and pathological features and outcomes of patients with HER2+ breast cancer regards to their BRCA status. Methods: Patients who were referred for genetic counseling between 2004-2012 and who had a HER2+ breast cancer treated with trastuzumab were included in our analysis. Patients were considered Her2+ if immunohistochemistry was 3+ or had a ratio of ≥2 by FISH. Patients with metastatic breast cancer at diagnosis were excluded. Clinical and pathological and outcome data was extracted from a prospectively maintained research data base after IRB approval was obtained. Results: Ninety-four patients were identified. The median age at diagnosis was 39 years (range 21 – 58). The majority of the patients were White (76%). Tumors were invasive ductal carcinoma in 89% and had nuclear grading of 3 in 76% of patients. Hormone receptors were positive in 66% and BRCA 1 or 2 mutations were positive in 16% (N=15). The majority of the patients were treated with a combination of Anthracyclines plus Taxanes (76%). All patients received trastuzumab in the neoadjuvant or adjuvant setting. After a median follow-up of 4.4 years, OS and DFS in all patients were 97% and 88%, respectively. Three HER2-positive breast cancer patients had died (3.2 %). Recurrence had occurred in 11 patients; all of these patients were BRCA negative. OS and DFS of patients with BRCA mutations were then compared with OS and DFS of patients without BRCA mutation (both 100% vs. 96% and 81.9%, respectively). There was no statistically significant survival difference in BRCA mutation carriers compared with non-carriers (p=0.362). Conclusions: The presence of a BRCA mutation does not seem to offer prognostic information in this population. Further investigation with larger cohort are needed for confirmation.