Efficacy and safety of neoadjuvant pd-1 inhibitor combined with chemotherapy in locally advanced esophageal squamous-cell carcinoma: A meta-analysis

Objective To systematically evaluate the efficacy and safety of neoadjuvant chemotherapy combined with PD-1 inhibitors in the treatment of locally advanced esophageal squamous cell carcinoma (ESCC).Methods Five databases were searched using computer retrieval to identify domestic and international open clinical trials or registered clinical trials on neoadjuvant immunotherapy for stage II-III esophageal cancer. All analyses were performed using R software (version 4.2.0). Two-tailed tests were used, and P<0.05 indicated statistical significance.Results A total of 8 studies, all single-arm phase II non-randomized controlled clinical trials, including 355 patients with locally advanced ESCC, were included in this study. The main outcome measures of neoadjuvant chemotherapy combined with PD-1 inhibitor treatment were: major pathological response (MPR) rate of 46%, pathologic complete response (pCR) rate of 29%; secondary outcome measures were: objective response rate (ORR) of 66%, disease control rate (DCR) of 100%, surgical resection rate of 100%, and treatment-related adverse events (TRAEs) occurrence rate of 16%. Subgroup analysis results showed no significant difference in MPR rate between the camrelizumab group and the toripalimab group (P=0.21), but there was a statistically significant difference in pCR rate (P=0.04), with the pCR rate in the camrelizumab group (33%, 95% CI:27-40%) higher than that in the toripalimab group (19%, 95% CI:10-31%).Conclusion Neoadjuvant chemotherapy combined with PD-1 inhibitors in the treatment of locally advanced ESCC can bring survival benefits to patients and has an overall good safety profile.