Twice-daily vs higher-dose once-daily thoracic radiotherapy for limited-disease small-cell lung cancer: A PRISMA-compliant meta-analysis

INTRODUCTION: The optimal dose and fractionation of thoracic radiotherapy (RT) for limited-disease small-cell lung cancer (LD-SCLC) remain controversial. This meta-analysis was performed to compare the efficacy and RT toxicity between twice-daily thoracic RT (45 Gy with 1.5 Gy twice daily) and higher-dose once-daily RT (60–72 Gy with 1.8 Gy/2 Gy once daily) administered with chemotherapy in LD-SCLC patients. METHODS: PubMed, EMBASE, Web of Science, and the Cochrane Library were searched up to March 19, 2020 for studies that compared twice-daily thoracic RT (45 Gy with 1.5 Gy twice daily over 3 weeks) with higher-dose once-daily RT (60–72 Gy with 1.8 Gy/2 Gy once daily over 6–8 weeks) in LD-SCLC patients. RESULTS: Five studies involving 13,726 patients were included in this analysis. Compared with the once-daily thoracic RT group, the 1-year overall survival (OS) rate (P < .001), the 2-year OS rate (P < .001), the 5-year OS rate (P < .001), the mOS (P < .001), and the 1-year LRFS rate (P = .048) were significantly improved in the twice-daily RT group. The toxic effects of RT (esophagitis: P = .293; pneumonitis: P = .103) were similar in both groups. CONCLUSION: Compared with the higher-dose once-daily regimen, the twice-daily thoracic radiotherapy regimen improved efficacy but did not increase RT toxicity in LD-SCLC patients.