Abstract
Compared with white women, black women have higher incidence rates for triple-negative breast cancer but lower rates for hormone receptor (HR)-positive cancers in the United States. Whether similar racial difference occurs in male breast cancer is unclear. We examined racial differences in incidence rates of breast cancer subtypes defined by HR and human epidermal growth factor receptor 2 (HER2) by sex using nationwide data from 2010 to 2016. Among men, rates were higher in blacks than whites for all subtypes, with the black-to-white incidence rate ratios of 1.41 (95% confidence interval [CI ]= 1.32 to 1.50) for HR+/HER-, 1.65 (95% CI = 1.40 to 1.93) for HR+/HER2+, 2.62 (95% CI = 1.48 to 4.43) for HR-/HER2+, and 2.27 (95% CI = 1.67 to 3.03) for triple-negative subtype. Conversely, among women, rates in blacks were 21% lower for HR+/HER2- and comparable for HR+/HER2+ but 29% and 93% higher for HR-/HER2+ and triple-negative subtypes, respectively. Future studies are needed to identify contributing factors to the dissimilar racial patterns in breast cancer subtype incidence between men and women.