Endoscopic Sphincterotomy Prior to Biliary Stenting for Malignant Biliary Obstruction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND AND AIMS: ERCP-guided biliary stenting is the usual palliative treatment for patients with unresectable malignant biliary obstruction (MBO). Previous studies suggested that ES prior to biliary stenting may not reduce the post-ERCP pancreatitis (PEP) risk and may increase bleeding risk. This systematic review and meta-analysis aimed to evaluate the effectiveness and safety of ES prior to biliary stenting in patients with MBO, with a particular focus on the impact of MBO etiology and stent type. METHODS: We systematically searched for randomized controlled trials (RCTs) comparing ERCP-guided biliary stenting with versus without ES in patients with MBO. We estimated the pooled risk ratios (RRs) with respective 95% confidence intervals (CIs) using a random-effects model. RESULTS: Six RCTs (1215 patients) were included. Technical success and the risk of PEP, clinically significant bleeding, perforation, cholangitis, cholecystitis, and stent malfunction were similar between the groups. Subgroup analyses by MBO etiology and stent type were consistent with overall analysis, except for PEP by MBO etiology. ES reduced PEP risk in studies with a low prevalence of pancreatic cancer (RR 0.23; 95% CI 0.12-0.44), but no significant difference was observed in studies with a high prevalence of pancreatic cancer (RR 0.85; 95% CI 0.57-1.28). CONCLUSION: The risk of clinically significant bleeding was similar with or without ES prior to biliary stenting for MBO. ES was associated with a reduced PEP risk in studies with a low prevalence of pancreatic cancer, whereas no benefit was observed in studies with a high prevalence of pancreatic cancer.