A systematic review and network meta-analysis protocol of neoadjuvant treatments for patients with gastric cancer

National Comprehensive Cancer Network (NCCN) guidelines recommend surgery, chemotherapy, and radiation therapy for gastric cancer patients. Neoadjuvant treatments as the administration of therapeutic agents before a main treatment gained in more and more attention. However, the role of neoadjuvant treatments is still controversial. The main aim of this systematic review and network meta-analysis is to assess the relative efficacy of different neoadjuvant treatment regimens for gastric cancer using network meta-analysis method. We will search 5 electronic databases to identify randomized controlled trials (RCTs) and non-RCTs compared the efficacy differences of surgery alone (S), preoperative chemotherapy follow by surgery (CTS), preoperative radiotherapy follow by surgery (RTS), and preoperative chemoradiotherapy follow by surgery (CRTS) for patients with gastric cancer. The risk of bias tool from the Cochrane Handbook version 5.1.0 will be used to assess the risk of bias of RCTs, and the risk of bias in nonrandomized studies of interventions (ROBINS-I) for non-RCTs. Data will be analyzed using R-3.4.1 software. The results of present network meta-analysis will estimate the relative efficacy among all interventions and rank the interventions even if head-to-head comparisons are lacking and will provide more evidence for clinicians, researchers, and patients in the management of gastric cancer.Protocol registration number: CRD42017074956.