Hormone receptor-positive breast cancer and black race: does sex matter?

Abstract

Black breast cancer patients have worse clinical outcomes than their White counterparts. There are few studies comparing clinical outcomes between Black male breast cancer (MBC) and female breast cancer (FBC) patients. The objective of this study is to examine differences in presentation, treatment, and mortality between Black MBC and FBC. The National Cancer Database was queried for all Black MBC and FBC patients, ages 18-90, with hormone receptor-positive breast cancer diagnosed between 2010 and 2016. Hormone receptor positivity was defined as estrogen receptor-positive, progesterone-positive and HER 2-negative cancer. Sociodemographic and clinical variables were compared between MBC and FBC patients on bivariable analysis. After propensity score matching, overall survival was evaluated using the log-rank test and Cox proportional hazards. Compared to FBC patients, MBC patients had higher rates of metastatic disease (stage 4, MBC 4.4% vs. FBC 2.6%, p < 0.001), larger tumors (tumor size < 2cm, MBC 32.1 vs. FBC 49.1%, p < 0.001) and a higher percentage of poorly differentiated tumors (grade 3, MBC 28.5% vs. FBC 21.4%, p < 0.001). MBC patients had lower rates of hormone therapy (MBC 66.4% vs. FBC 80.7%, p < 0.001) and neoadjuvant chemotherapy (MBC 5.8% vs. FBC 7.5%, p = 0.05) than FBC. On propensity score matched analysis, Black MBC patients had a higher overall mortality (p25 of 60months vs. 74months) compared to FBC patients (p = 0.0260). Among hormone receptor-positive Black MBC and FBC patients, there are sex-based disparities in stage, hormone therapy use and overall survival.