HER2/neu overexpression and survival in African-American women with breast cancer.

489 Purpose: It has been suggested that outcome disparities for African-American (AA) women with breast cancer, including late stage presentation and poorer survival, may in part be due to biological variation, including more aggressive features. We hypothesized that survival for AA women with HER2/neu positive breast tumors would be decreased. Methods: 311 consecutive AA patients were evaluated for HER2/neu status with immunohistochemistry (IHC) using polyclonal rabbit anti HER2/neu antibody (DAKO) on paraffin embedded tissue, at the Stroger Hospital of Cook County, Minority-Based Community Clinical Oncology Program (MBCCOP), which serves the medically-indigent in Chicago. HER2/neu IHC score of 3+ was considered positive for overexpression and IHC results from reference laboratories were validated with repeat in-house staining, which demonstrated no significant differences between methods (McNemar test p=0.648). Correlations were evaluated for disease-free (DFS), distant-disease-free (DDFS) and overall survival (OS). Results: The mean follow-up was 48 months and high AJCC stage, high tumor grade and negative hormone receptor (HR) status, were all significantly correlated with poorer survival. A total of 56 cases (18.1%) were HER2/neu positive and there was no correlation with DFS, DDFS, and OS. For DFS, 78 events occurred, Hazard Ratio (HR)=0.77, 95% Confidence Interval (95% CI)=0.41-1.47, p=0.43; for DDFS, 55 events occurred, HR=0.79, 95% CI=0.38-1.69, p=0.55; and for OS, 40 events occurred, HR=1.01, 95% CI=0.45-2.31, p=0.96. Negative HR status was the only significant predictor of HER2/neu positive tumor status (Odds Ratio=0.46, 95% CI=0.24-0.87, p=0.018). Conclusions: This study demonstrates that there was no difference in survival between AA women with HER2/neu positive and HER2/neu negative breast tumors. These results may be limited by the small sample size, short follow-up period and treatment variables, and further study is required.