Racial/Ethnic Disparities in All-Cause Mortality Among Patients Diagnosed with Triple-Negative Breast Cancer.

It is unclear whether racial/ethnic disparities in triple-negative breast cancer (TNBC) mortality remain after accounting for clinical characteristics, treatment, and access-to-care-related factors. In this study, women with a primary diagnosis of TNBC during 2010-2014 were identified from the National Cancer Database. Hazard ratios (HR) and 95% confidence intervals (CI) for 3- and 5-year all-cause mortality associated with race/ethnicity were estimated using Cox proportional hazards models with stepwise adjustments for age, clinical characteristics, treatment, and access-to-care-related factors. Of 78,708 patients, non-Hispanic (NH) black women had the lowest 3-year overall survival rates (79.4%), followed by NH-whites (83.1%), Hispanics (86.0%), and Asians (87.1%). After adjustment for clinical characteristics, NH-blacks had a 12% higher risk of dying 3 years post-diagnosis (HR=1.12, 95%CI: 1.07 to 1.17), while Hispanics and Asians had a 24% (HR=0.76, 95%CI: 0.70 to 0.83) and 17% (HR=0.83, 95%CI: 0.73 to 0.94) lower risk than their NH-white counterparts. The black-white disparity became non-significant after combined adjustment for treatment and access-to-care-related factors (HR=1.04, 95%CI: 0.99 to 1.09), while the white-Hispanic and white-Asian differences remained. Stratified analyses revealed that among women aged less than or equal to 50 with stage III cancer, the elevated risk among NH-blacks persisted (HR=1.20, 95%CI: 1.04 to 1.39) after full adjustments. Similar results were seen for 5-year mortality. Overall, clinical characteristics, treatment, and access-to-care-related factors accounted for most of the white-black differences in all-cause mortality of TNBC but explained little about Hispanic- and Asian-white differences.