Management of recurrent pancreatic cancer after surgical resection: a protocol for systematic review, evidence mapping and meta-analysis

Introduction Although recurrence rate among cases of resected pancreatic cancer are as high as 85%, an optimal treatment for recurrent pancreatic cancer (RePC) has not been established. Previous evidence regarding RePC is scarce, and randomised controlled trials (RCTs) are particularly lacking. The evidence mapping (EM) method has been introduced as a tool intended to complement the conventional systematic review (SR) and meta-analysis (MA) and is suitable for this issue. This review aims to investigate the optimal treatment options for RePC, using a newly developed automatic EM tool. Method and analysis All study types, including RCTs, non-randomised studies and other forms of observational studies will be included in the SR-EM. The Medline, Embase, Cochrane library and Scopus databases will be searched for reports of five treatment options for local and metastatic recurrences, including re-resection, chemotherapy, radiotherapy, best supportive care and other novel treatments, published from database inception to 30 April 2017. References from relevant studies will be searched manually. If meta-analysis is feasible, the primary outcome measure will be median overall survival. Two independent authors will select the studies and assess the risk of bias, and a third author will resolve discrepancies in consensus meeting. To visualise EM, we will use a novel web-based and open-access mapping programme, Plotting E-Map (PLOEM) (http://plotting-e-map.com). If eligible combinations of interventions for quantitative comparison are identified, we will conduct subgroup MAs using random-effect models and I-2 statistics. Publication bias will be visualised using funnel plots. Ethics and dissemination This study will not use primary data, and therefore formal ethical approval is not required. The findings will be disseminated through peer-reviewed journals and committee conferences.