摘要The present study assessed the efficacy and safety of thoracic radiotherapy(TRT)following first-line chemotherapy or chemoimmunotherapy in patients with extensive-stage small cell lung cancer(ES-SCLC),focusing on the influence of different TRT timing strategies(consolidative vs.salvage)on survival rates.We retrospectively analyzed a total of 54 patients with ES-SCLC treated between January 2019 and July 2022.Patients receiving consolidative TRT(cTRT)within three months after completion of first-line treatment were compared with those receiving salvage TRT(sTRT)after disease progression.The primary endpoints were overall survival(OS),progression-free survival(PFS),locoregional-free survival(LRFS),and distant metastasis-free survival(DMFS);the secondary endpoint included safety.The cTRT group(n=41)showed significantly longer median OS(26.6 vs.14.8 months,P=0.048),PFS(12.9 vs.3.5 months,P＜0.000 1),and DMFS(10.7 vs.3.4 months,P=0.0044)than the sTRT group(n=13).Multivariate analysis revealed that cTRT was an independent,favorable prognostic factor.No significant differences in OS or LRFS were observed between high-dose(≥ 50 Gy)and low-dose(＜50 Gy)TRT.Hematologic and respiratory toxicities were the most frequently reported adverse events,with acceptable tolerability.In conclusion,cTRT after chemoimmunotherapy significantly improves survival outcomes for ES-SCLC patients,and low-dose TRT may be a suitable option.