Comparison of capecitabine and oxaliplatin with S-1 as adjuvant chemotherapy in stage III gastric cancer after D2 gastrectomy

Aim To compare capecitabine and oxaliplatin (XELOX) with S-1 as adjuvant chemotherapy in stage III gastric cancer after D2 gastrectomy. Methods Clinical data from 206 patients who received XELOX or S-1 regimens as adjuvant chemotherapy in stage III gastric cancer were collected. Patients were divided into 2 groups according to regimen; the groups were XELOX (n = 114) and S-1 monotherapy (n = 92). Results 3-year disease-free survival (DFS) was higher in the S-1 group than in the XELOX group (66.6% vs 59.1%; p = 0.636).3-year overall survival (OS) was 75.6% in the S-1 group and 69.6% in the XELOX group (p = 0.495). But, the difference was not statistically significant. Especially, for patients with stage IIIC disease, 3-year overall survival was 55.2% in the XELOX group and 39.0% in the S-1 group (hazard ratio, HR 0.50, 95% confidence interval, CI 0.23-1.10; p = 0.075). In multivariate analysis, N stage (HR, 5.639; 95% CI, 1.297- 24.522; p = 0.021) and cycle completion as planned (HR, 5.734; 95% CI, 3.007-10.936; p<0.001) were independent predictors of overall survival. Conclusion Adjuvant XELOX and S-1 regimen did not prove anything superior for stage III gastric cancer in this study. But, XELOX had a tendency to be superior to S-1 in stage IIIC gastric cancer after D2 gastrectomy although the difference was not statistically significant. N stage and cycle completion as planned were prognostic factors.