Effects of S-1 combined with radiotherapy in the treatment of advanced esophageal cancer A systematic review and meta-analysis protocol

Background: Esophageal cancer is one of the worst malignant digestive neoplasms with poor treatment outcomes. Definitive concurrent chemoradiotherapy (CRT) has become the standard nonsurgical treatment option for locally advanced esophageal cancer. The chemotherapeutic drugs 5-fluorouracil and cisplatin have been most commonly used in CRT of esophageal cancer. However, radiotherapy combined with 5-FU/cisplatin often delivers severe toxicity to patients. S-1 as an oral chemotherapeutic drug exhibits higher anti-tumor activity, less adverse effects, and better biological availability. S-1 also has excellent effects as a CRT regimen for esophageal cancer. Methods: A systematic literature search will be performed through January 2018 using MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar for relevant articles published in any language. Randomized controlled trials, prospective comparative studies will be included. All meta-analyses will be performed using Review Manager software. The quality of the studies will be evaluated using the guidelines listed in the Cochrane Handbook. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statements will be followed until the findings of the systematic review and meta-analysis are reported. Results: The results of this systematic review and meta-analysis will be published in a peer-reviewed journal. Conclusion: Our study will draw an objective conclusion of the effects of S-1 combined with radiotherapy in the treatment of unresectable esophageal cancer and provide level I evidence for clinical decision makings.