Clinical efficacy of neoadjuvant immunochemotherapy versus neoadjuvant chemotherapy for local advanced gastric adenocarcinoma

Objective To evaluate the therapeutic efficacies of neoadjuvant immunochemotherapy (NAIC) and neoadjuvant chemotherapy (NAC) for local advanced gastric adenocarcinoma and analyze the clinicopathological characteristics. Methods A retrospective cohort study was conducted on 243 patients with locally advanced gastric cancer admitted in Army Medical Center of PLA (Daping Hospital) and the First Affiliated Hospital of China Medical University from January 2017 to July 2023. After balancing the confounding factors by inclusion and exclusion criteria and propensity score matching (PSM), the tumor pathological regression (TRG) rate and safety of the 2 neoadjuvant treatment regimens were analyzed, and the clinical pathological characteristics were analyzed to find clinical pathological characteristics related to efficacy. Results After using PSM to balance the baseline characteristics of the 2 groups of patients, 53 subjects in each group were included in the analysis. In terms of TRG, the pathological complete response (pCR) rate in the NAIC group (13 patients, 25%) was significantly higher than that in the NAC group (2 patients, 3.8%, P < 0.05). Similar results were observed in terms of major pathological response (MPR), with 23 patients (43%) in the NAIC group achieving MPR, while 9 patients (17%) in the NAC group achieved MPR (P < 0.05). In terms of safety, the incidence of treatment-related adverse events(TRAEs) of any grade in the NAIC group and the NAC group was comparable (96.2% and 96.2%, respectively). In an exploratory subgroup analysis of tumor pathological regression, the patients with clinicopathological features such as age < 65 years, male, stage Ⅲ~ⅣA of American Joint Committee on Cancer (AJCC) staging, histological type of adenocarcinoma, high-moderate differentiated, intestinal-type gastric cancer, stage T3~4 of clinical T-staging, and stage N2~3 of clinical N-staging were more likely to benefit from NAIC. Conclusion NAIC results in a higher rate of pathological regression and a comparable incidence of adverse events when compared with chemotherapy alone for patients with local advanced gastric adenocarcinoma.