Association of race/ethnicity, socioeconomic status, and breast cancer subtypes in the National Cancer Data Base (2010-2011)

To estimate the odds of breast cancer subtypes in minority populations versus non-Hispanic (NH) whites stratified by socioeconomic status (SES) [a composite of individual-level SES (insurance status) and area-level SES (median household income quartile from 2000 U.S. Census data)] using a large nationwide cancer database. We used the National Cancer Data Base to identify breast cancer cases diagnosed in 2010 and 2011, the only 2 years since U.S. cancer registries uniformly began collecting HER2 results. Breast cancer cases were classified into five subtypes based on hormone receptor (HR) and HER2 status: HR+/HER2-, HR+/HER2+, HR-/HER2+ (HER2-overexpressing), HR-/HER2- (TN), and unknown. A polytomous logistic regression was used to estimate odds ratios (ORs) comparing the odds of non-HR+/HER2-subtypes to HR+/HER2- for racial/ethnic groups controlling for and stratifying by SES, using a composite of insurance status and area-level income. Compared with NH whites, NH blacks and Hispanics were 84 % (OR = 1.84; 95 % CI 1.77-1.92) and 17 % (OR = 1.17; 95 % CI 1.11-1.24) more likely to have TN subtype versus HR+/HER2-, respectively. Asian/Pacific Islanders (API) had 1.45 times greater odds of being diagnosed with HER2-overexpressing subtype versus HR+/HER2- compared with NH whites (OR = 1.45; 95 % CI 1.31-1.61). We found similar ORs for race in high and low strata of SES. In a large nationwide hospital-based dataset, we found higher odds of having TN breast cancer in black women and of HER2-overexpressing in API compared with white women in every level of SES.