Racial Differences in Adjuvant Endocrine Therapy Use and Discontinuation in Association with Mortality among Medicare Breast Cancer Patients by Receptor Status

There are racial disparities in breast cancer mortality. Our purpose was to determine whether racial/ethnic differences in use and discontinuation of adjuvant endocrine therapy (AET) differed by hormone receptor status and whether discontinuation was associated with mortality. We conducted a retrospective cohort study with SEER/Medicare dataset of women age ≥65 years diagnosed with stage I-III breast cancer in Medicare Part-D from 2007 to 2009, stratified by hormone receptor status. We performed multivariable logistic regressions to assess racial differences for the odds of AET initiation and Cox proportional hazards models to determine the risk of discontinuation and mortality. Of 14,902 women, 64.5% initiated AET