Radiotherapy improves the survival of patients with metastatic esophageal squamous cell carcinoma: a propensity score matched analysis of Surveillance, Epidemiology, and End Results database

The survival advantage of radiotherapy (RT) for patients with metastatic esophagus cancer has not been adequately evaluated. This study aims to find out the role of RT for metastatic esophagus cancer and to find the different effect forRT to esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC). This study included 5,970 metastatic esophagus cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database, registered from January 2004 to December 2013. Propensity score (PS) analysis with 1:1 nearest neighbor matching method was used to ensure well-balanced characteristics of all comparison groups by histological types. The Kaplan-Meier and Cox proportional hazardous models were used to evaluate the overall survival (OS), cancer-specific survival (CSS), and corresponding 95% confidence interval (CI). Generally speaking, EAC did not get survival benefit from RT (median OS for RT group vs. no-RT group-8.0, 7.6-8.4 vs. 9.0, 8.5-9.5, P = 0.073), whereas RT for metastatic ESCC did significantly improve OS (median OS for RT group vs. no-RT group-8.0, 7.4-8.6 vs. 7.0, 6.4-7.6, P = 0.044). Therefore, compared with adenocarcinoma, ESCC could get more survival benefit from RT.