Chemoradiation versus chemotherapy or radiation alone in stage III endometrial cancer: Patterns of care and impact on overall survival

Purpose: We aimed to investigate the patterns-of-care and overall survival (OS) benefit of aCRT versus adjuvant monotherapy (aMT), defined as either chemotherapy or radiation alone, utilizing a large national registry of patients.

Patients and methods: Adult patients with stage III endometrial adenocarcinoma diagnosed from 2004 to 2013 were included. Logistic and Cox regression modeling was used to identify factors predictive of receipt of aCRT and OS, respectively. Survival analysis was performed with Kaplan Meier and log-rank analysis. Propensity score matching and sensitivity analysis was performed to address selection bias and presence of potential confounding variables.

Results: A total of 21,027 patients were identified: 11,435 (54.4%) patients received aMT, while 9592 (45.6%) received aCRT. Utilization of aCRT increased over the study period (p<0.01). Factors predictive of receiving aCRT include private insurance (OR: 1.67, 95% CI: 1.30-2.14), Medicare (OR: 1.33, 95% CI: 1.01-1.75), FIGO stage IIIC disease (OR: 1.36, 95% CI: 1.19-1.54), lymphovascular space invasion (OR: 1.14, 95% CI: 1.03-1.27), and lymph node surgery performed (OR: 1.42, 95% CI: 1.15-1.74). Median survival in years for aCRT, RT, and CT was 10.3, 7.1, and 5.6, respectively (p<0.001). Compared to aMT, aCRT was associated with a decrease risk of death on multivariate analysis (HR: 0.62, 95% CI: 0.56-0.70). The benefit of aCRT over aMT persisted after propensity score matching.

Conclusion: The use of aCRT for stage III endometrial cancer is increasing. Multiple clinical and demographic factors were predictive of aCRT use. When compared to chemotherapy or radiation alone, aCRT is associated with an OS benefit.