Types of Self-Expandable Metal Stents for Palliative Drainage of Unresectable Extrahepatic Malignant Biliary Obstruction: A Network Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: The optimal self-expandable metallic stent (SEMS) choice for endoscopic drainage of unresectable extrahepatic malignant biliary obstruction (MBO) with endoscopic retrograde cholangiopancreatography (ERCP) remains unclear due to limited randomized controlled trial (RCT) evidence. Prior meta-analyses have relied on observational data, introducing heterogeneity and bias. To overcome these limitations, an RCT-only network meta-analysis (NMA) was performed to evaluate the efficacy and safety of SEMS types. METHODS: A literature search was conducted to identify RCTs assessing fully covered SEMS (FCSEMS), partially covered SEMS (PCSEMS), and/or uncovered SEMS (UCSEMS) for ERCP drainage of unresectable extrahepatic MBO. Study outcomes included recurrent biliary obstruction (RBO), specific causes of RBO, overall survival (OS), and adverse events (AEs). A frequentist NMA was performed to estimate hazard ratios (HRs) and incidence rate ratios (IRRs) with their 95% confidence intervals and overall P-scores. RESULTS: Ten RCTs (1,659 patients) were included. There were no significant differences in time to RBO, incidence of any RBO, or OS between stent types. UCSEMS had the lowest rates of stent migration, tumor overgrowth, and sludge occlusion, whereas FCSEMS most effectively prevented tumor ingrowth. AE rates were similar across groups; however, only FCSEMS, but not PCSEMS, had significantly higher rates of acute cholecystitis than UCSEMS in patients with an intact gallbladder. CONCLUSION: There were no differences in RBO, OS, or AE excluding acute cholecystitis between each SEMS type, although each type has its advantages and disadvantages. FCSEMS was associated with a higher risk of acute cholecystitis, emphasizing careful patient selection, particularly regarding gallbladder status.