Tumor subtype and race in male breast cancer: A population-based cohort study.

Abstract

149 Background: Subtypes of female breast cancer have been shown to vary by race, however data on the significance of molecular profiling and the distribution of subtype according to race/ethnicity for male breast cancer is lacking and warrants research. We sought to investigate the differences in male breast cancer according to tumor subtypes and racial/ethnic profiles using the Surveillance, Epidemiology, and End Results Program (SEER) database. Methods: We used the SEER database (SEER 18 registries) to identify all cases of male breast cancer diagnosed between 2010 and 2012. The cases were classified based on estrogen receptor (ER), progesterone receptor (PR) and HER2 status as follows: ER and/or PR positive and HER2−; ER and/or PR and HER2 +; ER−, PR−, and HER2 +; and triple negative (ER−, PR−, and HER2−). We sought the association between the subtype and race, which is categorized as non-Hispanic (NH) white, NH black, NH Asian Pacific Islander (API) and Hispanic men. Results: We identified 1515 cases of male breast cancer diagnosed during the study period; 188 were excluded because of unknown race or subtype, and the remaining 1327 were included in our final cohort. 96.8% of cases were ER positive and less than 3.2% of cases were ER negative. 1145 patients (86.1%) were HR+/HER2-, 139 patients (10.0%) were HR+/HER2+, 12 patients (0.7%) were HR-,HER2+, and 31 patients (2.3%) were triple negative (Table 1).Tumor subtype did not vary by race/ethnicity (p = 0.08). Conclusions: Our results indicate that unlike female breast cancer that male breast cancer subtype does not vary by race/ethnicity. Further research is warranted to determine how these findings may impact the treatment and prognosis of male breast cancer. [Table: see text]