Assessing the efficacy of adjuvant chemotherapy in patients with T3N0 gastric cancer.

BACKGROUND: Adjuvant chemotherapy is standard for advanced gastric cancer based on randomized controlled trials. However, its effectiveness in patients with T3N0 stage, who were not included in these trials, remains unclear. This study assessed its clinical benefits by comparing outcomes between patients with T3N0 stage who received postoperative chemotherapy with those who did not. METHODS: From 2011 to 2019, a retrospective analysis was performed on 386 patients with pathologically diagnosed T3N0 advanced gastric cancer who underwent radical gastrectomy. Inverse probability of treatment weighting (IPTW) was used to analyze overall survival(OS) and relapse-free survival (RFS) between groups. RESULTS: Among 386 patients, 188 received adjuvant chemotherapy and 198 underwent surgery alone. After IPTW adjustment, the 5-year OS were 93.1 % in the adjuvant chemotherapy group and 91.3 % in the surgery-only group, and the 5-year RFS were 88.4 % and 84.4 %, respectively. Adjuvant chemotherapy was not associated with a significant reduction in the risk of death (hazard ratio [HR], 0.72; 95 % confidence interval [CI], 0.32-1.61; P = 0.428) or recurrence (HR, 0.68; 95 % CI, 0.34-1.34; P = 0.264). Overall recurrence rates and recurrence patterns were comparable between the two groups after adjustment. Among patients who received chemotherapy, grade III/IV adverse events occurred in 26.7 % of those treated with TS-1 and 70.4 % of those treated with XELOX. CONCLUSION: In patients with T3N0 stage after surgery, the chemotherapy group demonstrated OS and RFS similar to surgery-only group. Therefore, the benefit of adjuvant chemotherapy in patients with T3N0 gastric cancer remains uncertain.