Abstract A136: Racial disparities in delayed initiation of adjuvant endocrine therapy among patients with breast cancer
Authors: Lee Kimberley T , Stearns Vered , Jacobs Lisa K 
Published: September 2020

Adjuvant endocrine therapy (AET) is associated with significant improvements in disease-free and overall survival for patients with hormone receptor positive (HR+) breast cancer and guidelines recommend initiation of AET within 12 months of diagnosis. Black women with HR+ breast cancer have poorer overall survival than their white counterparts and breast cancer is the leading cause of cancer death for Hispanic women. We aim to describe the relationship between race/ethnicity and prolonged time to AET and identify other predictors of delayed AET. This is a retrospective, population-based cohort study using the National Cancer Database, which captures more than 70% of incident cancer cases in the US. We examined 249,761 women who were diagnosed with invasive stage IB to III, HR+, HER2- breast cancer between 2004 and 2014, had cancer-directed surgery, and who were prescribed AET. Time to AET was defined as time from breast cancer diagnosis to initiation of AET. Delayed AET was defined as more than 12 months from date of breast cancer diagnosis. Multivariable logistic regression models were used to identify predictors of delayed AET. Eighty percent (186,197) of women were white, ~10% (22,841) were black, and 5% (12,101) were Hispanic. Among all patients, mean age at diagnosis was 58.5 years, 29% were diagnosed with stage IB, 43% with stage II, and 27% with stage III cancer, and median time to initiation of AET was 6.1 months. Mean age of black and Hispanic women at diagnosis was 56.4 and 53.9 years respectively, compared to 59.2 years for white women. Fourteen and 20% of black and Hispanic patients were insured by Medicaid, respectively, versus 4.4% of white women. Black and Hispanic women had almost twice the odds of delayed time from diagnosis to surgery compared to white women (OR 1.78, 95% 1.73-1.83 and OR 1.93, 95% CI 1.86-2.01, respectively). In univariate analyses, factors associated with delayed AET were black and Hispanic race/ethnicity, being uninsured or having Medicaid, older age (categorized as &gt; 70 years¬), higher tumor grade or stage, receipt of chemotherapy or radiation therapy, and delayed time to surgery or chemotherapy. Our final multivariable model adjusted for these significant factors, as well as comorbidities, urban/rural residence, and income and education (based on zip-code). In this model, being uninsured was no longer positively associated with delay in AET. Black patients had a 19% higher odds of delayed AET (OR 1.19, 95% CI 1.14-1.24) and Hispanic patients had 57% higher odds of delay compared to their white counterparts (OR 1.57, 95% CI 1.49-1.65). There are racial disparities in the quality of breast cancer care provided to patients in this study. Being of black or Hispanic race/ethnicity was associated with increased odds of delayed time to initiating AET beyond the recommended time frame of 12 months after diagnosis. Medicaid enrollment was also a predictor of delayed time to AET. Future efforts should be focused on improving delivery of quality breast cancer care measures to vulnerable populations.

Citation Format: Kimberley T Lee, Vered Stearns, Lisa K Jacobs. Racial disparities in delayed initiation of adjuvant endocrine therapy among patients with breast cancer [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A136.