Above- Versus Across-The-Papilla Plastic Stent Placement for Malignant Hilar Biliary Obstruction in Unresectable Biliary Tract Cancer: A Multicentre IPTW Analysis

Abstract

Background

Maintaining effective biliary drainage is crucial in the era of prolonged chemotherapy for biliary tract cancer (BTC). Plastic stents (PS) are widely used in malignant hilar biliary obstruction (MHBO); nonetheless, the optimal placement (above- vs. across-the-papilla) remains controversial.

Methods

In this multicentre retrospective study, 246 patients with unresectable BTC-related MHBO who underwent clinically successful PS placement between April 2016 and August 2024 were analyzed. Patients were classified into the above-the-papilla (n = 197) and across-the-papilla (n = 49) groups. Baseline imbalances were adjusted using inverse probability of treatment weighting (IPTW) with “average treatment effect on the treated”. Covariates included age, sex, primary disease, Bismuth classification, cholangitis, prior drainage, and number of stents. The primary outcome was time to recurrent biliary obstruction (TRBO); secondary outcomes included overall survival (OS) and adverse events (AEs).

Results

After IPTW adjustment, effective sample sizes were 47.6 (above-the-papilla group) and 49.0 (across-the-papilla group). The median TRBO was significantly longer in the above-the-papilla group (114 vs. 66 days; p = 0.02), with a hazard ratio of 1.62 (95% confidence interval: 0.97–2.70). OS (457 vs. 366 days; p = 0.99) and AE rates were comparable.

Conclusions

Above-the-papilla PS placement may prolong stent patency without compromising safety in patients with unresectable BTC-related MHBO.