Comparison of S-1 plus oxaliplatin (SOX) and capecitabine plus oxaliplatin (XELOX) as adjuvant chemotherapies for stage II and III gastric cancer after D2 resection: A single-center retrospective study

Abstract

Background: Capecitabine plus oxaliplatin (XELOX) as adjuvant therapy for gastric cancer (GC) reduces cancer recurrence and improves survival. S-1 plus oxaliplatin (SOX) is well-tolerated and effective against advanced GC, and also be used widely in adjuvant treatment. However, data comparing SOX and XELOX as adjuvant treatments are lacking. Method: Data on treatment modalities, adverse events, recurrence and metastasis were collected from 180 patients with stage II and III GC, who received SOX or XELOX after D2 gastrectomy between January 2012 and December 2015, and analyzed retrospectively. The primary endpoint was 3-year disease-free survival (DFS) rate. Results: Median follow was 52.9 months; 3-year DFS rate and overall survival (OS) rate were 75.2% and 67.6% (P = 0.359) and 81.2% and 83.3% (P = 0.77) in the SOX and XELOX groups, respectively. There was no significant difference in peritoneal metastasis rates in the SOX and XELOX groups (8.6% vs 15%, respectively; P = 0.232). Compound recurrent disease was associated with significantly shorter OS. Multivariate analysis identified metastatic lymph node ratio (LNR) as an independent prognostic factor for OS (P = 0.036; hazard ratio = 2.875; 95% confidence interval, 1.069–7.729); the LNR ≥17% group had inferior 3-year OS rate to the LNR <17% group (P = 0.001). The incidence of grades 3 and 4 adverse events was similar in both groups; however, grade ≥2 hand–foot syndrome was significantly less frequent in the SOX group (P = 0.01). Conclusion: SOX has similar survival benefits to XELOX and is well-tolerated in Chinese patients with GC following D2 gastrectomy.