Comparison of S-1-based vs. capecitabine-based adjuvant chemotherapy for patients with gastric cancer: a systematic review and meta-analysis.

ABSTRACT

BACKGROUND: S-1-based and capecitabine-based adjuvant treatments are proved efficacious for patients with gastric cancer, but conventional meta-analyses of the direct comparisons between two alternative adjuvant regimens to resection of GC have not been attempted. AIM: The aim of this review was to compare the disease-free survival, overall survival and adverse events in patients receiving the S-1- and capecitabine-based adjuvant chemotherapies for treatment of gastric cancer (GC) patients undergoing resection. METHODS: A search of the academic literature was performed in PUBMED, SCOPUS, CENTRAL and EMBASE databases along with manual search in relevant journals for studies in English, to identify comparative studies comparing the effect of S-1-based chemotherapy and capecitabine-based adjuvant chemotherapy (AC), used in combination with surgical resection for treatment of gastric cancer. Both qualitative and quantitative analyses was carried out for all the included studies. The hazard ratios (HR) of disease-free survival (DFS) and overall survival (OS) were pooled using generic inverse variance method. The included studies were assessed for risk of bias using ROBINS-E (risk of bias in non-randomized studies of exposures) tool. RESULTS: Seven retrospective cohort studies, two prospective cohort studies and one randomized clinical trial were included. Both S-1- and capecitabine-based adjuvant chemotherapy for treatment of stage 2 or 3 gastric cancer had similar effects on the 3-year and 5-year DFS rates, overall survival and adverse events in the included studies. There was no difference in the adjusted hazard ratios (HR) of OS and DFS (0.86 95% CI (0.68, 1.09); p = 0.21 and 0.96 95% CI (0.75, 1.24), respectively). Oral mucositis was increasingly associated with S-1-based AC, while incidences of adverse events such as neutropenia, anaemia and thrombocytopenia were similar to those of capecitabine-based regimen. The quality of the included studies was found to be low to moderate. CONCLUSION: S-1- and capecitabine-based adjuvant chemotherapies can be used interchangeably as an adjuvant chemotherapeutic regimen postradical gastrectomy with D2 lymph node dissection.