Disparities in Adjuvant Treatment of High-Grade Endometrial Cancer in the Medicare Population

Background Black women experience worse survival with high grade endometrial cancer. Differences in adjuvant treatment have been proposed to be major contributors to this disparity. Little is known about the differences in type or timing of adjuvant treatment as it relates to race/ethnicity in the Medicare population. Objectives To examine patterns of adjuvant therapy and survival for non-Hispanic Black women compared to non-Hispanic White women and Hispanic women who have undergone surgery for high grade endometrial cancer in the Medicare population. Study design We utilized the Surveillance, Epidemiology, and End Results-Medicare Linked database to identify women who underwent surgery as a primary treatment for uterine grade 3 endometrioid adenocarcinoma, carcinosarcoma, clear cell carcinoma, or serous carcinoma between the years 2000 and 2015. Women who did not identify as White or Black race or Hispanic ethnicity were excluded. Multinomial logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for receiving a treatment delay or not receiving adjuvant treatment (compared to those who received adjuvant treatment within 12 weeks) adjusted for clinical and demographic characteristics. Overall survival was stratified by race/ethnicity, route of surgery, operative complications, and type and timing of adjuvant therapy were analyzed using the Kaplan-Meier method. Cox proportional hazards regression was used to estimate hazard of death by race/ethnicity adjusted for known predictors, as well as surgical outcomes and adjuvant therapy patterns. Results 12,201 women met study inclusion criteria. Non-Hispanic Black patients had a significantly worse five-year overall survival than Hispanic and non-Hispanic White patients (30.9 months vs 51.0 months vs 53.6 months, respectively). Approximately 8.6% of patients who received adjuvant treatment experienced a treatment delay (632/7,282). Delay in treatment of greater than or equal to 12 weeks was significantly different by race/ethnicity (p=0.034), with 12% of Hispanic, 9% of non-Hispanic Black, and 8% of non-Hispanic White women experiencing a delay. After adjustment for number of complications, age, histology (endometrioid vs non-endometroid), FIGO stage, marital status, comorbidity count, surgical approach, lymph node dissection, and urban-rural code, Hispanic women had a 71% increased risk of treatment delay (OR 1.71, CI 1.23-2.38) for all stages of disease. In the same model, non-Hispanic Black race was independently predictive of decreased use of adjuvant treatment for FIGO stage II and higher (OR 1.32, CI 1.04-1.68). Non-Hispanic Black race, number of perioperative complications, and non-endometrioid histology were predictive of worse survival in univariate models. Treatment delay was not independently predictive of worse 1- or 5-year survival at any stage. Conclusions Non-Hispanic Black race is predictive of worse 5-year survival across all stages and is also associated with omission of adjuvant treatment in ≥FIGO Stage II high grade endometrial cancer. In unadjusted analyses, patients who experience treatment omission or delay experienced poorer overall survival, but these factors were not independently associated in multivariate analyses. This study suggests race/ethnicity is independently associated with type and timing of adjuvant treatment in patients with high grade endometrial cancer. Further efforts to identify specific causes of barriers to care and timely treatment are imperative.