Socioeconomic inequality and omission of adjuvant radiation therapy in high-risk, early-stage endometrial cancer.

OBJECTIVE: Gaps in access to appropriate cancer care, and associated cancer mortality, have widened across socioeconomic groups. We examined whether demographic and socioeconomic factors influenced receipt of adjuvant radiation therapy (RT) in patients with high-risk, early-stage endometrial cancer.
METHODS: A retrospective study cohort was selected from 349,404 endometrial carcinoma patients from the National Cancer Database in whom adjuvant RT would be recommended per national guidelines. The study included surgically treated patients with endometrioid endometrial cancer with one of the following criteria: 1) FIGO 2009 stage IB, grade 1/2 disease, age ≥ 60 years; 2) stage IB, grade 3 disease; or 3) stage II disease. Logistic regression analysis was performed to identify factors associated with omission of adjuvant RT. Association between adjuvant RT, covariables, and overall survival (OS) was assessed with multivariable Cox proportional hazards models.
RESULTS: 19,594 patients were eligible for analysis; 47% did not receive adjuvant RT. Omission of adjuvant RT was more prevalent among African-American, Hispanic, and Asian compared to non-Hispanic white patients (OR 0.79, 95%CI: 0.69-0.91; OR 0.75, 95%CI: 0.64-0.87; OR 0.75, 95%CI: 0.60-0.94, respectively). Lower median household income of patient's area of residence, lack of health insurance, treatment at non-academic hospitals, farther distance to treatment facilities, and residence in metropolitan counties were associated with omission of adjuvant RT. Such omission was independently associated with worse OS (HR1.43, p < 0.001).
CONCLUSION: Adjuvant RT is omitted in 47% of patients with early-stage, high-risk endometrial cancer, which is associated with poor access to appropriate, high-quality care and worse outcome.