More than treatment refusal: a National Cancer Database analysis of adjuvant treatment refusal and racial survival disparities among women with endometrial cancer

Disparities in adjuvant treatment between Black and White women with endometrial cancer exist and contribute to worse outcomes among Black women. However, factors leading to disparate treatment receipt are understudied. We examined whether patient refusal of adjuvant treatment (chemotherapy or radiation) differed between Black and White women and whether treatment refusal mediated racial disparities in survival among women with endometrial cancer. We used the National Cancer Database, a hospital-based cancer registry, to identify non-Hispanic Black and non-Hispanic White women diagnosed with endometrial cancer from 2004 to 2016 who either received or refused recommended radiation or chemotherapy. We used logistic regression to estimate multivariable-adjusted odds ratios and 95% confidence intervals for associations between race and treatment refusal. We also examined predictors of treatment refusal in race-specific models. Accelerated failure time models were used to estimate absolute differences in overall survival by race. We used causal mediation analysis to estimate the proportion of racial differences in overall survival attributable to racial differences in adjuvant treatment refusal. We considered the overall study population and strata defined by histology, and adjusted for sociodemographic, tumor, and facility characteristics. Our analysis included 75,447 endometrial cancer patients recommended to receive radiation and 60,187 endometrial cancer patients recommended to receive chemotherapy, among which 6.4% and 11.4% refused treatment, respectively. Among Black women recommended for radiation or chemotherapy, 6.4% and 9.6% refused, respectively. Among White women recommended for radiation or chemotherapy, 6.4% and 11.8% refused, respectively. After adjusting for sociodemographic variables, facility characteristics, and tumor characteristics, Black women were more likely to refuse chemotherapy than White women (adjusted odds ratio, 1.26; 95% confidence interval, 1.15–1.37), but no difference in radiation refusal was observed (adjusted odds ratio, 1.00; 95% confidence interval, 0.91–1.11). Some predictors of radiation refusal varied by race, namely income, education, histology, stage, and chemotherapy receipt (P interactions