Comparative effectiveness and safety of biliary drainage strategies for malignant biliary obstruction: a protocol for systematic review and network meta-analysis.

introductionMalignant biliary obstruction (MBO) is a common complication of pancreaticobiliary and periampullary malignancies and is associated with substantial morbidity and reduced survival. Multiple biliary drainage strategies are available, including endoscopic, percutaneous and surgical approaches, as well as adjunctive therapies. However, direct head-to-head comparisons remain limited, and the relative effectiveness and safety of these interventions are not well established. This study aims to compare the effectiveness and safety of different biliary drainage strategies for MBO using a network meta-analysis, allowing both direct and indirect comparisons and enabling ranking of treatment strategies. METHODS AND ANALYSIS: This protocol is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines. We will systematically search MEDLINE via PubMed, Embase via Elsevier, Web of Science Core Collection via Clarivate, and the Cochrane Central Register of Controlled Trials via the Cochrane Library from inception to 30 June 2026. Randomised controlled trials (RCTs) and non-randomised comparative studies will be included. Interventions of interest include endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound-guided biliary drainage (EUS-BD), percutaneous transhepatic biliary drainage (PTBD), surgical bypass and adjunctive therapies combined with drainage (eg, photodynamic therapy or radiofrequency ablation). Primary outcomes will include technical success, clinical success and quality of life. Secondary outcomes will include adverse events, reintervention rates, overall survival, 30-day all-cause mortality, stent patency duration and length of hospital stay. Risk of bias will be assessed using the Cochrane Risk of Bias two tool for RCTs and the ROBINS-I tool for non-randomised studies. A random-effects network meta-analysis will be conducted within a frequentist framework. Consistency and transitivity assumptions will be assessed, and treatment ranking will be estimated using the surface under the cumulative ranking curve. Subgroup analyses will be performed according to clinically relevant factors, including obstruction site, stent type, tumour type and treatment setting. The certainty of evidence will be evaluated using the GRADE approach adapted for network meta-analysis. ETHICS AND DISSEMINATION: Ethical approval is not required, as this study is based on published data. Findings will be disseminated through peer-reviewed publication. PROSPERO REGISTRATION NUMBER: CRD420261373097.