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

## TL;DR

A study compared two types of metal stents for biliary drainage in patients with unresectable malignant biliary strictures and found no significant differences in effectiveness or survival.

## Contribution

This randomized multicenter trial provides evidence on the comparative efficacy of partially covered versus uncovered metal stents in malignant biliary obstruction.

## Key findings

- Partially covered and uncovered stents showed similar patency and survival rates.
- Tumor ingrowth was rare and no patency advantage was observed with partially covered stents.
- Procedure-related complications trended higher with partially covered stents but were not statistically significant.

## Abstract

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

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.

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%;
P
= 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).

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.