High-dose versus standard-dose radiotherapy in concurrent chemoradiotherapy for inoperable esophageal cancer: A systematic review and meta-analysis

•High-dose had similar survival benefits to standard-dose radiotherapy in EC.•In ESCC patients, high-dose radiotherapy had better OS.•The incidence of radiation pneumonitis was higher in high-dose radiotherapy. The aim of this study was to evaluate the effectiveness and safety of high-dose (HD-RT) versus standard-dose radiotherapy (SD-RT) in concurrent chemoradiotherapy (CCRT) for inoperable esophageal cancer (EC) patients. A systematic search of the literature was conducted by screening PubMed, Web of Science, EMBASE and Cochrane Library databases before October 7, 2022 to collect controlled clinical studies of high-dose (≥60 Gy) and standard-dose (50–50.4 Gy) radiation in CCRT for EC. For statistical analysis, a fixed-effects model was used to synthesize HR and OR if there was no significant heterogeneity among studies; otherwise, a random-effects model was employed. There were ten studies with 4625 patients included in the study, 3667 of whom (79.3%) were esophageal squamous cell carcinoma (ESCC). The HD-RT group had no significant benefits in overall survival (OS) (HR = 0.88, 95% confidence interval [CI] = 0.74–1.05, P = 0.16) and progression-free survival (HR = 0.84, 95%CI = 0.67–1.04, P = 0.12) in total EC patients, compared with SD-RT group. However, in ESCC subgroup analysis, compared with SD-RT group, a better OS was observed in the HD-RT group (HR = 0.78, 95%CI = 0.70–0.88, P