Disparities in adjuvant treatment of high-grade endometrial cancer in the Medicare population.

Background: Black women experience worse survival effects with high-grade endometrial cancer. Differences in adjuvant treatment have been proposed to be major contributors to this disparity. However, little is known about the differences in type or timing of adjuvant treatment as it relates to race and ethnicity in the Medicare population.

Objective: This study aimed to examine patterns of adjuvant therapy and survival for non-Hispanic Black women vs non-Hispanic White women and Hispanic women who have undergone surgery for high-grade endometrial cancer in the Medicare population.

Study Design: We used the Medicare-linked Surveillance, Epidemiology, and End Results 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 and 95% confidence intervals for receiving a treatment delay or not receiving adjuvant treatment (compared with those who received adjuvant treatment within 12 weeks) adjusted for clinical and demographic characteristics. Overall survival was stratified by race and ethnicity, route of surgery, operative complications, and type and timing of adjuvant therapy, which were analyzed using the Kaplan-Meier method. Cox proportional-hazards regression was used to estimate the hazard ratio of death by race and ethnicity adjusted for known predictors and surgical outcomes and adjuvant therapy patterns.

Results: A total of 12,201 women met the study inclusion criteria. Non-Hispanic Black patients had a significantly worse 5-year overall survival than Hispanic and non-Hispanic White patients (30.9 months vs 51.0 months vs 53.6 months, respectively). Approximately 632 of 7282 patients (8.6%) who received adjuvant treatment experienced a treatment delay. Delay in treatment of ≥12 weeks was significantly different by race and ethnicity (P=.034), with 12% of Hispanic, 9% of non-Hispanic Black, and 8% of non-Hispanic White women experiencing a delay. After adjustment for the number of complications, age, histology (endometrioid vs nonendometroid), International Federation of Gynecology and Obstetrics stage, marital status, comorbidity count, surgical approach, lymph node dissection, and urban-rural code, Hispanic women had a 71% increased risk of treatment delay (odds ratio, 1.71; 95% confidence interval, 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 the International Federation of Gynecology and Obstetrics stage II and higher (odds ratio, 1.32; 95% confidence interval, 1.04-1.68). Non-Hispanic Black race, number of perioperative complications, and nonendometrioid 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.

Conclusion: Non-Hispanic Black race was predictive of worse 5-year survival across all stages and was associated with omission of adjuvant treatment in International Federation of Gynecology and Obstetrics stage II or higher 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 that race and ethnicity are independently associated with the 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.