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

Abstract

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.

Efficacy of S-1 or Capecitabine Plus Oxaliplatin Adjuvant Chemotherapy for Stage II or III Gastric Cancer after Curative Gastrectomy: A Systematic Review and Meta-Analysis

“…In 2020, Lee et al conducted a PSM multicenter cohort study with 1:3 matching between the S-1 and CAPOX groups, using the nearest-neighbor matching method [ 16 ]. In 2021, Oh et al performed a retrospective large-scale single-center observational study [ 17 ]. The median follow-up periods of the three studies were 52.3 months, 59.0 months, and 55.0 months, respectively.…”

“…Among these, we excluded 6741 studies since they were reviews, books, or meta-analyses, and we included 11,880 clinical trials and randomized controlled studies. Based on the titles and abstracts of the 11,875 studies, five clinical studies comparing S-1 versus CAPOX as AC in patients undergoing gastrectomy were selected [ 14 , 15 , 16 , 17 , 18 ]. Two of these studies were excluded because they collected data from a relatively short-term three-year follow-up after gastrectomy [ 14 , 18 ].…”

“…Two of these studies were excluded because they collected data from a relatively short-term three-year follow-up after gastrectomy [ 14 , 18 ]. The remaining three studies were analyzed using a forest plot, and the results are reported herein [ 15 , 16 , 17 ].…”

“…The between-group effect size was computed by calculating the pooled hazard ratio (HR) and 95% confidence interval (CI). The staged OS rates were not presented in two of the previous papers; therefore, OS in previous studies were analyzed by the authors in previous papers, and then the staged OS data were included in this meta-analysis [ 16 , 17 ].…”

“…On the other hand, among the studies analyzing five-year postoperative survival, two studies that conducted PSM showed comparable oncologic outcomes between the two regimens [ 15 , 16 ]. A single-center, observational study presented the potential for superior efficacy of the CAPOX regimen against stage II gastric cancer [ 17 ].…”