Short term efficacy and safety of PD-1 inhibitor and apatinib plus S-1 and oxaliplatin as neoadjuvant chemotherapy for patients with locally advanced gastric cancer.

Abstract

Surgical resection is the cornerstone of treatment for locally advanced gastric cancer (LAGC). Hence, downstaging of the tumor with neoadjuvant therapy is critical for R0 resection and prolongs the overall survival. Data from related studies are lacking, and the literature is scarce. Therefore, a single arm-study was performed on PD-1 inhibitor and apatinib plus S-1 and oxaliplatin as neoadjuvant chemotherapy for patients with LAGC. The findings are expected to serve as a reference for neoadjuvant therapy for LAGC. We assessed 130 LAGC patients using PD-1 inhibitor, apatinib plus S-1, and oxaliplatin as neoadjuvant chemotherapy from January 2021 to October 2022. A total of 104 patients received gastric transcatheter chemoembolization (GTC). The primary endpoint was the rate of clinical complete response, pathological complete response, and safety, while the secondary endpoints were the R0 resection rate and objective response rate of the disease and the disease control rate. A total of 130 patients completed the clinical assessment, of which 6 patients (4.6%) achieved clinical complete response, 87 patients (66.9%) achieved partial response, 30 patients (23.0%) achieved stable disease, and 7 patients (5.5%) experienced progressive disease. The overall response rate was 71.5% (93/130), and the disease control rate was 94.5% (123/130). A remarkable downstaging effect was observed in this study. Downstaging of the T stage and N stage was achieved in 71.5% and 80% of the patients, respectively, which translated into a high R0 resection rate. The findings revealed that 125 patients underwent R0 resection, and the R0 resection rate was 96.1%. According to the observed results, 21.6% of the patients achieved pathological complete response after neoadjuvant chemotherapy. Gastric transcatheter chemoembolization in the first cycle of neoadjuvant therapy was beneficial for tumor regression (P < .001). All adverse events were relieved and disappeared after symptomatic treatment, and no grade 4 adverse events were noted. PD-1 inhibitor and apatinib plus S-1 and oxaliplatin are safe and effective as neoadjuvant treatment of LAGC. Gastric transcatheter chemoembolization is useful for tumor regression during neoadjuvant therapy.