SIB-RT plus S-1 improves survival in elderly inoperable esophageal cancer

PURPOSE: This study reports the long-term outcomes of simultaneous integrated boost radiotherapy (SIB-RT) combined with oral S-1 chemotherapy (CRTCT) in inoperable patients aged ≥ 70 years with inoperable esophageal squamous cell carcinoma (ESCC). METHODS: In this multicenter, phase III randomized trial, patients with inoperable, locally advanced stage II-IV ESCC were randomized to receive either CRTCT or RT alone. The primary endpoint was overall survival (OS); secondary endpoints included progression-free survival (PFS), restricted mean survival time (RMST), and patterns of failure. RESULTS: After a median follow-up of 75 months, patients in the CRTCT group had longer OS than those in the RT group (hazard ratio (HR), 0.74; 95 % confidence interval (CI), 0.57-0.95; P = 0.02), with better 5-year OS rates (34.1 % vs. 23.6 %,P = 0.02), PFS (31.1 % vs. 20.9 %,P = 0.02), and RMST (33.0 vs. 27.0 months,P = 0.02). CRTCT's effect on OS stabilized over 5 years. Locoregional failure was lower in the CRTCT group (HR, 0.64; 95 % CI, 0.45-0.92; P = 0.02), with similar distant and mixed failure risks. CONCLUSIONS: SIB-RT combined with oral S-1 chemotherapy significantly improved long-term survival and therefore might be considered a standard of care for elderly patients with inoperable ESCC. TRIAL REGISTRATION Clinical Trials.gov Identifier: NCT0297969.