Racial disparities in treatment and outcomes between Hispanic and non-Hispanic black women with triple-negative breast cancer.

Introduction: Triple-negative breast cancer (TNBC) is an aggressive breast cancer (BC) subtype with higher incidence and mortality rates in non-Hispanic Black (NHB) women than non-Hispanic Whites. Studies assessing disparities between NHB and Hispanic women, the two largest US racial/ethnic minorities, are lacking. This study evaluates disparities in the treatment and outcomes between NHB and Hispanic women with non-metastatic TNBC.

Methods: This observational, population-based study using the SEER database included adult, female patients diagnosed with non-metastatic TNBC between 2010 and 2015 and identified as NHB or Hispanic. Logistic regression analysis was used to examine the adjusted odds of receiving breast cancer-directed treatment. Kaplan-Meier and cumulative incidence of death curves were plotted to assess overall survival (OS) and risk of breast cancer-related death, respectively. Multivariate regression analyses with Cox and Fine-Gray methods were calculated to assess factors associated with OS and breast cancer-related death, respectively.

Results: There were 3426 Hispanic and 5419 NHB patients with non-metastatic TNBC. Hispanics had better 5-year OS relative to NHB (76% vs. 72%). No differences in the odds of receiving chemotherapy or surgery between cohorts was seen. However, the odds of undergoing breast-conserving surgery (BCS) and receiving radiation was higher in NHB than Hispanics, (OR, 1.22; 95% CI, 1.10-1.36) and (OR, 1.50; 95% CI, 1.36-1.66), respectively. Lack of radiation therapy was associated with increased BC-related death in NHB relative to Hispanics (sHR, 1.40; 95% CI, 1.19-1.65). Nevertheless, this difference was not seen when radiation was given, (sHR, 1.03; 95% CI, 0.87-1.23).

Conclusions: We found racial disparities in treatment and outcomes between NHB and Hispanics. NHB were more likely to receive radiation therapy and have BCS. Still, after adjusting for demographic and treatment-related factors, NHB had worse OS and BCSS relative to Hispanics. Additional research is needed to understand the drivers of these disparities.