Impact of Adjuvant Chemotherapy on Survival of the Patients with pT1N + M0 Gastric Cancer: A Retrospective Cohort Study.

[BACKGROUND] The advantages of postoperative adjuvant chemotherapy (ACT) for gastric cancer patients with pT1N + M0 staging have been a subject of debate. This study aims to assess whether ACT can enhance the overall survival (OS) of postoperative pT1N + M0 gastric cancer patients when compared to surgery alone.

[METHODS] A total of 329 postoperative patients with pT1N + M0 gastric cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2015). Patients were stratified into surgery-alone and surgery-plus-chemotherapy groups. Multivariate Cox regression identified prognostic factors, followed by subgroup analyses stratified by clinical characteristics.

[RESULTS] This study included 329 patients, of whom 80 received postoperative ACT and 249 underwent surgery alone. Multivariate analysis revealed that race, tumor primary site, differentiation grade, clinical stage, N stage, and ACT were independent prognostic factors for OS. Subgroup analysis demonstrated that the survival benefit of ACT was more pronounced in Asian/Pacific Islander (API) patients (hazard ratio [HR], 0.320; 95% confidence interval [CI], 0.140-0.732; P for interaction = 0.028) and in those with N1 stage (HR, 0.447; 95% CI, 0.272-0.737; P for interaction = 0.022).

[CONCLUSION] ACT was associated with a survival benefit versus surgery-alone in pT1N + M0 gastric cancer, especially among API patients or those with N1 stage.