Comparative Effectiveness of Adjuvant XELOX Versus TS-1 Monotherapy After D2 Gastrectomy for Stage III Gastric Cancer: A Real-World Nationwide Cohort Study.

Adjuvant XELOX (capecitabine plus oxaliplatin) and TS-1 (S-1) monotherapy are both guideline-recommended following D2 gastrectomy for gastric cancer, yet head-to-head real-world data exclusively in stage III disease remain scarce. Using Taiwan's National Health Insurance Research Database linked to the Taiwan Cancer Registry-Long Form, we identified stage III gastric cancer patients who underwent D2 gastrectomy (2010-2019) and received adjuvant XELOX or TS-1 for ≥3 months. Propensity score matching balanced chemotherapy and non-chemotherapy cohorts (1706/group). Overall survival (OS) was the primary endpoint; disease progression was defined as initiation of FOLFOX salvage chemotherapy (used as a pragmatic proxy for disease recurrence). A second propensity score matching was performed directly between XELOX (n = 533) and TS-1 (n = 893) groups, yielding 490 matched pairs with well-balanced baseline characteristics. Multivariable Cox regression was adjusted for sex, age, comorbidities, and Charlson Comorbidity Index. TS-1 was associated with significantly better OS (adjusted HR 0.73, 95% CI 0.61-0.86;