Survival benefit of radiotherapy in metastatic esophageal cancer: a population-based study

Background: Population-based estimates of survival benefits of radiotherapy on metastatic esophageal cancer (EC) are lacking. The aim of this study was to analyze survival benefits of radiotherapy in patients with metastatic EC at the time of cancer diagnosis. Methods: Patients with metastatic EC were selected from Surveillance, Epidemiology, and End Results databases. The covariates included radiotherapy status, age, sex, insurance, histological type, differentiation, metastatic sites (bone, brain, liver, lung), and chemotherapy. Propensity score matching model was used to reduce bias of patients' selection. Median overall survival (OS) and cancer-specific survival (CSS) were compared and Cox regression analysis was performed. Results: A total of 4,761 patients with metastatic EC met the selection criteria. It was found that radiotherapy significantly improved 2-year OS (P=0.020) and 2-year CSS (P=0.009) in matched patients. In the propensity score model (N=3,672), Cox regression analysis demonstrated that radiotherapy was an independent prognostic factor which associated with a longer OS (P< 0.001) and esophageal cause-specific survival in matched patients (P< 0.001). Additionally, age, sex, insurance status, differentiation, number of metastatic sites and chemotherapy were also found to be significantly associated with OS and CSS in matched patients. Conclusions: The population-based study demonstrated that patients with metastatic EC might benefit from radiotherapy. This data supports the proposal to change the current management for patients with metastatic EC.