Partially covered or uncovered metal stent efficacy in malignant unresectable distal biliary obstruction (METARSI): Randomized multicenter trial.

[BACKGROUND AND STUDY AIMS] There is no consensus regarding optimal selection of self-expandable stents (SEMS) for biliary drainage with endoscopic retrograde cholangiopancreatography (ERCP). This study compared stent dysfunction, patient survival, and adverse events in patients with unresectable malignant distal biliary strictures (DBS) treated with ERCP, randomized to partially covered (PC-SEMS) or uncovered (U-SEMS) stents.

[PATIENTS AND METHODS] A prospective, multicenter, randomized controlled trial was performed in adult patients with DBS (March 2021-February 2023) with 12-month follow-up. Analyses were conducted according to intention-to-treat (ITT) and per-protocol (PP) principles. Procedural and post-procedural outcomes were evaluated using PP analyses and stent patency was evaluated with Kaplan-Meier analysis.

[RESULTS] Among 261 patients, 130 were randomized to PC-SEMS and 131 to U-SEMS. Baseline features were similar between groups (mean age 73 ± 11 years; 51% male). Most strictures were due to pancreatic adenocarcinoma (75%), and 49% of patients had metastatic disease. Overall, stent dysfunction was comparable (11% vs 14%; = 0.70). No significant differences were observed in patient survival (108 vs 100 days). A trend toward higher procedure-related complications was noted with PC-SEMS (2% vs 7%; not significant).

[CONCLUSIONS] PC-SEMS and U-SEMS in unresectable DBS showed comparable patency, survival, and stent dysfunction rates, with tumor ingrowth rarely observed and a trend toward more procedure-related complications in PC-SEMS. In this group with limited survival, there was no observed patency advantage with PC-SEMS. Potential benefit of PC-SEMS in populations with longer prognosis warrants further study.