Prognostic effect of adjuvant chemoradiotherapy for patients with gastric cancer: an updated evidence of randomized controlled trials

The prognostic effect of chemoradiotherapy in gastric cancer has been evaluated for decades while the results are still in debate and heterogeneous. We thus comprehensively updated the evidence through systematic review and meta-analysis to evaluate chemoradiotherapy in gastric cancer to determine its effect. Pubmed, EMBASE, and Cochrane Library from the earliest possible year to April 2017 were searched. Randomised controlled trials (RCTs) that assessed the effects of combined chemoradiotherapy for patients with gastric cancer compared with that of single chemotherapy were included. The main outcome measure was 5-year overall survival (OS) and the second was disease-free survival (DFS) or recurrence-free survival (RFS). Fifteen RCTs involving 3347 patients were included into this meta-analysis. Compared with single chemotherapy, the relative risk (RR) for 5-year OS for chemoradiotherapy was 1.05 (95% CI 0.88 to 1.25), with moderate heterogeneity across eligible trials (I(2) = 55.7%, p = 0.016). Subgroup analyses and sensitivity analyses confirmed the consistent findings. We found that significant survival benefit for 5-year DFS/RFS for chemoradiotherapy over single chemotherapy (RR 0.89 95% CI 0.81 to 0.98) for patients with gastric cancer. This updated meta-analysis does not provide strong evidence for a 5-year survival benefit of chemoradiotherapy over chemotherapy alone in patients with gastric cancer. A clear advantage of chemoradiotherapy over chemotherapy has not been established. Further larger RCTs should be conducted to determine its true effect.