Age and Endometrial Cancer Survival Disparities Among Black and White Insured Patients.

Importance: Black patients with endometrial cancer have nearly twice the mortality of White patients with endometrial cancer, but it is unclear if the disparity differs by age, independent of insurance status. Objective: To compare, in a large cohort of insured patients, the disparity between Black and White individuals in survival for patients aged younger than 65 years vs those age 65 years or older and to assess the association of age with excess mortality among Black patients. Design, Setting, and Participants: This retrospective cohort study looked at comparative data from a community-based integrated health care system for Black and White patients diagnosed with endometrial cancer from January 1, 2005, to December 31, 2022. Data were analyzed between June 2025 and January 2026. Exposure: Black and White race. Main Outcomes and Measures: The disparity in 5-year mortality between Black and White patients was first assessed among patients younger than 65 years and those 65 years and older. The degree to which the gap in mortality in each age strata was accounted for by demographic, comorbid, tumor, treatment, and socioeconomic characteristics was further assessed using Cox proportional hazards models adjusted for these factors. To test whether age modifies the association between Black race and excess mortality, interaction terms between race and age were examined. Results: From a sample of 13 585 patients, 11 530 White individuals and 2055 Black individuals, 6543 (48.2%) were younger than 65 years of age at diagnosis and 7042 (51.8%) were aged at least 65 years. The unadjusted hazard ratio (HR) for death among Black patients compared with White patients was 2.59 (95% CI, 2.21-3.03) for patients younger than 65 and 1.56 (95% CI, 1.40-1.73) for those aged at least 65 years at diagnosis. Comorbidities, tumor characteristics, treatment, and socioeconomic status accounted for the disparity among older patients (adjusted HR, 1.10; 95% CI, 0.97-1.24), but among younger patients some of the disparity remained unexplained (adjusted HR, 1.24; 95% CI, 1.04-1.49). Factors more associated with mortality among younger vs older Black patients were high-grade nonendometrioid disease (aHR, 6.09; 95% CI, 4.75-7.81 vs aHR, 3.42; 95% CI, 2.94-3.97) and distant disease (aHR, 8.38; 95% CI, 6.56-10.71 vs aHR, 4.97; 95% CI, 4.31-5.72). The adjusted hazard for mortality for Black women compared with White women was larger among patients younger than 65 years compared with older patients (multiplicative scale: aHR, 1.43; 95% CI, 1.18-1.75). Conclusions and Relevance: In this cohort study of 13 585 insured Black and White patients, the racial disparity in endometrial cancer survival was 43% larger among younger patients, associated with greater racial imbalances in the risk of adverse tumor types and distant disease, although some of the disparity remains unexplained.