12-mm Versus 10-mm Metallic Stents for Malignant Biliary Obstructions: A Systematic Review and Meta-Analysis

Background and aims: Endoscopic drainage of malignant biliary obstruction using metal stents is widely used to treat obstructive jaundice. However, the occurrence of stent occlusion or migration raises the hypothesis using stents with larger diameters may be associated with better outcomes.

Methods: PubMed, Embase, and Cochrane databases were systematically searched for studies comparing 10-mm vs. 12-mm covered metallic stents for recurrent unresectable biliary obstruction. The primary outcomes were recurrent biliary obstruction (RBO) and time to RBO (TRBO). Statistical analyses were performed using R software version 4.3.1. The risk ratio (RR) was used for binary outcomes, with their respective 95% confidence interval (CI). Heterogeneity was assessed using the Cochran Q test and I2 statistics.

Results: We included five studies-one randomized clinical trial and four cohort studies-totaling 520 patients. Among these, 280 received 10-mm stents, while 240 were treated with 12-mm stents. The 12-mm stent is associated with a greater TRBO (HR 1.72; 95% CI 1.36 to 2.18), lower incidence of RBO (RR 0.59; 95% CI 0.44 to 0.78; I2=34%), and stent obstruction (RR 0.52; 95% CI 0.34 to 0.81; I2=33%). No significant differences were found for stent migration and adverse events rate between groups.

Conclusion: The 12-mm metallic stents significantly increase stent patency and reduce the incidence of RBO and stent obstruction in managing recurrent unresectable biliary obstruction, with no differences regarding stent migration and adverse events compared to 10-mm stents.