A meta-analysis of efficacy and safety of S-1 monotherapy or combination therapy as first-line treatment in metastatic colorectal cancer

Purpose To compare the efficacy and safety profile of S-1-based versus non-S-1-based chemotherapy as first-line treatment in mCRC. Methods Relevant randomized controlled trials (RCTs) were obtained from PubMed, Embase, and Ovid databases and the Cochrane library from database set up in May 2018. The RCTs of S-1-based monotherapy or combination therapy as first-line treatment were selected. The impact of S-1-based chemotherapy on progression-free survival (PFS) and overall survival (OS) was assessed by pooling data via RevMan 5.3. Results Meta-analysis of 10 RCTs showed that S-1-based chemotherapy significantly improved PFS (HR 0.90, 95% CI 0.84–0.97, P = 0.006). In subgroup analysis, there was a statistically significant increase in PFS when S-1-based chemotherapy was compared with 5-FU-based (HR 0.92, 95% CI 0.84–1.00, P = 0.04) or capecitabine-based chemotherapy (HR 0.85, 95% CI 0.73–0.99, P = 0.04). The meta-analysis of OS (HR 0.95, 95% CI 0.86–1.05, P = 0.36), overall response rate (ORR) (HR 0.99, 95% CI 0.84–1.17, P = 0.90), and disease control rate (DCR) (HR 1.61, 95% CI 0.87–3.00, P = 0.13) showed no statistical significance between S-1-based and non-S-1-based chemotherapy. The statistically significant differences in the meta-analysis indicated less incidence of graded 3–4 leucopenia (OR = 0.30, 95% CI 0.13–0.71, P = 0.006) and hand–foot syndrome (HFS) (OR = 0.24, 95% CI 0.10–0.58, P = 0.001) in the S-1-based chemotherapy, and there was no statistically significant difference for other adverse events. Conclusions S-1-based chemotherapy in mono or combined therapy was an attractive alternative to standard first-line regimen for patients of mCRC.