Racial disparities in survival outcomes by breast tumor subtype among African American women in Memphis, Tennessee.

Racial disparities in survival among African American (AA) women in the United States have been well documented. Breast cancer mortality rates among AA women is higher in Memphis, Tennessee as compared to 49 of the largest US cities. In this study, we investigated the extent to which racial/ethnic disparities in survival outcomes among Memphis women are attributed to differences in breast tumor subtype and treatment outcomes. A total of 3527 patients diagnosed with stage I-IV breast cancer between January 2002 and April 2015 at Methodist Health hospitals and West Cancer Center in Memphis, TN were included in the analysis. Kaplan-Meier survival curves were generated and Cox proportional hazards regression were used to compare survival outcomes among 1342 (38.0%) AA and 2185 (62.0%) non-Hispanic White breast cancer patients by race and breast tumor subtype. Over a mean follow-up time of 29.9 months, AA women displayed increased mortality risk [adjusted hazard ratio (HR), 1.65; 95% confidence interval (CI), 1.35-2.03] and were more likely to be diagnosed at advanced stages of disease. AA women with triple-negative breast cancer (TNBC) had the highest death rate at 26.7% compared to non-Hispanic White women at 16.5%. AA women with TNBC and luminal B/HER2- breast tumors had the highest risk of mortality. Regardless of race, patients who did not have surgery had over five times higher risk of dying compared to those who had surgery. These findings provide additional evidence of the breast cancer disparity gap between AA and non-Hispanic White women and highlight the need for targeted interventions and policies to eliminate breast cancer disparities in AA populations, particularly in Memphis, TN.