Suprapapillary Versus Transpapillary Plastic Stents for Unresectable Malignant Hilar Biliary Obstruction

Overview

Bile duct blockage caused by cancer near the liver hilum (where the bile ducts join) leads to jaundice and infection. The standard treatment is to place a plastic stent (a small tube) through an endoscope to drain the bile. Conventionally, the stent is placed across the papilla, the opening between the bile duct and the intestine, with one end inside the intestine. An alternative method places the stent entirely inside the bile duct, above the papilla, which may reduce bacterial contamination from the intestine and help the stent stay open longer. However, previous studies have shown inconsistent results. This multicenter randomized trial will compare these two stent placement methods in patients with unresectable malignant hilar biliary obstruction. About 70 participants will be randomly assigned (50:50) to receive either a suprapapillary (above the papilla) or a transpapillary (across the papilla) plastic stent during the same standard endoscopic procedure (ERCP). Both stents are approved, commonly used medical devices. The main question is which method keeps the bile duct open longer before re-blockage. Participants will be followed with regular clinic visits, and safety will be monitored throughout the study.

Malignant hilar biliary obstruction (MHBO) is among the most challenging conditions in therapeutic biliary endoscopy. Uncovered self-expandable metal stents provide longer patency but cannot be removed, which complicates reintervention as oncologic therapy prolongs survival. Plastic stents remain a removable, reversible option, though with shorter patency. The suprapapillary (inside) plastic stent concept, proposed in 1998, aims to prolong stent patency and reduce ascending bacterial infection by preserving the sphincter of Oddi, but existing evidence is limited to small trials and retrospective series with inconsistent results, and no adequately powered randomized trial has addressed high-grade hilar obstruction. This is an investigator-initiated, multicenter, open-label, parallel-group randomized controlled trial conducted at eight institutions in Taiwan. Patients with unresectable Bismuth type II or higher MHBO are randomized 1:1 to suprapapillary or transpapillary plastic stent placement. Randomization is performed after successful biliary cannulation during ERCP, using a centralized web-based system (REDCap) with stratification by site. The primary endpoint is time to recurrent biliary obstruction (TRBO). Secondary endpoints include overall survival, technical and clinical success, reintervention rate, and adverse events. Participants are followed until recurrent biliary obstruction, death, or the end of the study period.