Efficacy and Safety of Neoadjuvant Chemoimmunotherapy in Resectable Esophageal Squamous Cell Carcinoma: A Meta-analysis

Purpose. This study aimed to summarize the efficacy and safety of neoadjuvant chemoimmunotherapy in resectable esophageal squamous cell carcinoma (ESCC). Methods. Literature focusing on the efficacy and safety of neoadjuvant immunotherapy or chemoimmunotherapy in resectable ESCC published before June 2022 was retrieved from PubMed, Embase, Cochrane Library, and Web of Science. The risk of bias was assessed using the Cochrane risk-of-bias assessment tool. Subgroup and sensitivity analyses were further performed. Results. A total of 452 patients from 15 studies were included in this meta-analysis. All of the studies explored the efficacy and safety of neoadjuvant chemoimmunotherapy. The pooled major pathological response (MPR) rate and pathological complete response (PCR) rate were 58.3% and 32.9%, respectively. The pooled incidence of treatment-related adverse events (TRAEs) and serious adverse events (SAEs) were 91.6% and 19.4%, respectively. The pooled R0 resection rate was 92.8%, and the resection rate was 81.1%. Incidence of anastomotic leakage, pulmonary infection, and postoperative hoarseness were 10.7%, 21.3%, and 13.0%, respectively. Compared with 2 cycles of neoadjuvant therapy, patients who received > 2 cycles of neoadjuvant therapy showed higher MPR rate (57.3% vs. 61.1%) and PCR rate (30.6% vs. 37.9%), and the incidence of TRAEs (89.2% vs. 98.9%) tended to be higher. However, no significant difference was found (P > 0.05). Two cycles of neoadjuvant therapy showed higher R0 resection rate and resection rate (R0 resection rate: 96.0% vs. 87.8%, P = 0.02; resection rate: 85.6% vs. 74.7%, P = 0.01). Pembrolizumab- and tislelizumab-based neoadjuvant therapy showed higher MPR rate (72.4% and 72.2%) and PCR rate (41.5 % and 50.0%). Compared with other ICIs, tislelizumab-based neoadjuvant therapy showed lower R0 resection rate (80.5%). The pooled incidence of SAEs for pembrolizumab-based neoadjuvant therapy (2.0%) was lower. Camrelizumab-based neoadjuvant therapy showed lower incidence of pulmonary infection (11.5%). Conclusions. Neoadjuvant chemoimmunotherapy is effective and safe for resectable ESCC.