Abstract 1178: Racial/ethnic disparities in overall mortality among patients diagnosed with triple negative breast cancer
Authors: Wang Fei , Zheng Wei , Bailey Christina E. , Pietenpol Jennifer A. , Shu Xiao-Ou 
Published: September 2020

Abstract
Background: Black women are more likely to die of triple negative breast cancer (TNBC) than women of other races and ethnicities in the United States. However, it is unclear whether this disparity remains after accounting for differences in clinical characteristics, treatment regimens and factors related to access to care.
Methods: Women with a primary diagnosis of TNBC between 2004 and 2014 were identified from the National Cancer Database. Hazard ratios (HR) and 95% confidence intervals (CI) for 5-year all-cause mortality in association with race/ethnicity (i.e., non-Hispanic [NH] white, NH-black, Hispanic, Asian, and other group) were estimated using Cox proportional hazard models with stepwise adjustments for age, clinical characteristics, as well as treatment and access-to-care related factors. Stratified analyses by stage and age (i.e., ≤50 years and &gt;50 years) were also conducted.
Results: Of 82,653 study populations, there were 53,908 NH-white (65.2%), 17,350 NH-black (21.0%), 5,116 Hispanic (6.2%) and 2,334 Asian (2.8%) patients. Compared to NH-white patients, a higher proportion of NH-black and Hispanic patients were diagnosed with stage III/IV cancer (21.4%, 20.8%, and 16.4% for NH-black, Hispanic, and NH-white patients, respectively, P&lt;0.001), while the proportion was similar between NH-white and Asian (15.2%) patients. NH-black patients had the lowest 5-year overall survival rates (72.5%), followed by NH-white (75.7%), Hispanic (79.7%), and Asian patients (82.1%, P&lt;0.001). After adjustment for age and clinical characteristics, NH-black patients had 9% higher 5-year mortality (HR=1.09, 95%CI: 1.05-1.14), while Hispanic and Asian patients had a 23% (HR= 0.77, 95%CI=0.72 to 0.83) and 18% (HR=0.82, 95%CI=0.73 to 0.91) lower 5-year mortality than NH-white counterparts. The black-white disparity became non-significant after further adjustment for factors related to access-to-care (HR=1.03, 95%CI: 0.98-1.07), while the white-Hispanic and white-Asian differences persisted. With a few exceptions, these association patterns were consistent across cancer stages and age groups. Among women aged ≤50 years with stage III cancer, NH-blacks showed higher mortality than NH-whites (fully adjusted HR=1.19, 95% CI: 1.03-1.36). Asian patients with stage III/IV cancer had similar mortality risk as their NH-white counterparts.
Conclusions: After accounting for clinical characteristics, treatment and factors related to access-to-care, there is little white-black difference in 5-year all-cause mortality, but Hispanic and Asian patients in general had lower mortality compared with white patients.
Citation Format: Fei Wang, Wei Zheng, Christina E. Bailey, Jennifer A. Pietenpol, Xiao-Ou Shu. Racial/ethnic disparities in overall mortality among patients diagnosed with triple negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1178.