Perioperative treatment strategies for gastric cancer: A retrospective real-world study in China.

e16107 Background: Adjuvant chemotherapy with fluoropyrimidine and platinum remains a standard treatment following gastrectomy across Asia. Despite its widespread adoption, postoperative outcomes remain suboptimal. Neoadjuvant therapies have demonstrated efficacy in tumor downstaging and in addressing micro-metastases in locally advanced gastric cancer. The combination of immunotherapy and chemotherapy has shown promising tumor remission rates and improved objective response rates (ORR). This study evaluates the effectiveness of perioperative immune checkpoint inhibitors (ICIs) combined with chemotherapy compared to conventional perioperative regimens in real-world practice for gastric cancer. Methods: Data were retrospectively collected from patients undergoing perioperative treatment and surgery for gastric cancer at the First Affiliated Hospital of Zhejiang University School of Medicine (January–December 2020). Cohorts were grouped by treatment strategies, assessing their 3-year disease-free survival (DFS) and overall survival (OS). Patient survival data were followed until December 31, 2023. Results: Among 345 patients (70.1% male), 93 (27.0%) experienced recurrence and 37 (10.7%) died. The 3-year DFS rates were 78.6% (perioperative immunochemotherapy), 73.3% (perioperative chemotherapy), and 80.5% (postoperative adjuvant chemotherapy). Three-year OS rates were 92.9%, 91.7%, and 94.1%, respectively. Both perioperative immunochemotherapy and chemotherapy showed earlier pathological staging over adjuvant chemotherapy (p<0.001). Immunochemotherapy achieved a 56.6% major pathological response (MPR), exceeding chemotherapy's 31.0% MPR (p<0.01). Complete pathological response in the immunochemotherapy group was 24.5% versus 8.0% in chemotherapy. Conclusions: Perioperative immunochemotherapy significantly improves pathological downstaging and MPR but requires longer follow-up to assess survival benefits. The 3-year DFS and OS rates and pathological response evaluation. Treatment Strategy 3Y-DFS (%) 3Y-OS (%) MPR (%) Perioperative Immunochemotherapy 78.6 92.9 56.6 Perioperative Chemotherapy 73.3 91.7 31.0 Adjuvant Chemotherapy 80.5 94.1 NA