Safety and short-term outcomes of esophagectomy after neoadjuvant immunotherapy combined with chemotherapy or chemoradiotherapy for locally advanced esophageal squamous cell cancer: analysis of two phase-II clinical trials

Background: Preoperative chemotherapy (CT) or chemoradiotherapy (CRT) show survival benefits in patients with locally advanced esophageal squamous cell carcinoma (ESCC); however, ESCC patients still have a dismal prognosis. We conducted two phase-II, single-armed clinical trials to assess the potential benefits, efficacy, feasibility, and safety of esophagectomy after combining preoperative CT or CRT and neoadjuvant programmed cell death protein 1 (PD-1) inhibitors in the treatment of ESCC. Methods: Patients were included with histologically confirmed ESCC (clinical stage II-IVA according to the American Joint Committee on Cancer 8 th staging system) from two phase-II, single-arm trials (NCT04506138 and NCT03940001). Patients underwent two doses of intravenous PD-1 inhibitor (either camrelizumab or sintilimab) every 3 weeks, combined with two cycles of either CT or CRT. The primary endpoint of the study was the safety and short-term outcomes of esophagectomy as measured by the risk of developing complications within 30 days, after the combination of preoperative PD-1 inhibitor and CT or CRT Secondary endpoint was to evaluate the pCR rates (pT0N0), primary tumor pCR rates (pT0), operation time, postoperative stay, and 30-day mortality rate between both groups. Results between both groups were compared using a multivariable log-binomial regression model to obtain the adjusted relative risk ratios (RRs). Results: Between May 2019 and June 2022, 55 patients were included. All patients completed neoadjuvant therapy. Age, sex, performance status, clinical stage, histologic subtype, procedure type, operative time, and blood loss volume were similar between the two groups. The primary tumor pCR rates were 52.9% in the nICRT group and 21.6% in the nICT group (P=0.03), while the postoperative pCR rates were 41.2% in the nICRT group and 21.6% in the nICT group (P=0.19). The minimally invasive surgery rates were 89.2% (33/37) in the nICT group and 94.1% (16/17) in the nICRT group. The risk of developing pulmonary, anastomotic, or other complications were similar between the two groups. Conclusions: Esophagectomy was safe after the addition of the PD-1 inhibitor to preoperative CT or CRT in ESCC neoadjuvant therapies. Follow-up and the exploratory endpoints, including biomarkers analyses, are ongoing.