Comparison of Long-Term Efficacy in S-1 and Capecitabine With Oxaliplatin as Adjuvant Chemotherapy for Patients With Gastric Cancer After Curative Surgery: A Retrospective, Single-Center Observational Study

Purpose: Various adjuvant chemotherapies have been introduced for gastric cancer patients after gastrectomy with D2 lymph node dissection. Although the mainstream regimen of adjuvant chemotherapy in Korea includes S-1 monotherapy (TS-1) and capecitabine with oxaliplatin (XELOX), few studies have compared the long-term efficacies of these 2 regimens. Methods: Between January 2010 and June 2017, 2021 patients were diagnosed with gastric cancer and underwent curative resection with adjuvant chemotherapy at our institution. Of 1461 patients with stage IB-III gastric cancer, 825 received TS-1 and 636 received XELOX as adjuvant chemotherapy. We retrospectively reviewed their medical records and analyzed the postoperative 5-year overall survival (OS) and disease-free survival (DFS) of these 2 groups. Results: The patients in the XELOX group had more advanced stage of cancer than the TS-1 group (stages III and II: 56.6% and 43.1%, respectively, in XELOX and 35.3% and 57.0% in TS-1; P < .001). The DFS did not differ significantly between the 2 study groups at any pathologic stage. The OS differed significantly only at pathologic stages IIA (P = .024) and IIB (P = .015). In a multivariate analysis of stage II patients, type of regimen was an independent prognostic factor of OS (XELOX vs TS-1; hazard ratio: 0.47, 95% confidence interval: 0.25-0.89, P = .021). Conclusion: There were similar long-term efficacies between these 2 regimens in advanced gastric cancer patients who underwent curative surgery. However, the XELOX regimen might be favorable for OS of stage II patients.