Suprapapillary Versus Transpapillary Plastic Stents for Unresectable Malignant Hilar Biliary Obstruction

Malignant hilar biliary obstruction (MHBO) is among the most challenging conditions intherapeutic biliary endoscopy. Uncovered self‐expandable metal stents provide longerpatency but cannot be removed, which complicates reintervention as oncologic therapyprolongs survival. Plastic stents remain a removable, reversible option, though withshorter patency. The suprapapillary (inside) plastic stent concept, proposed in 1998,aims to prolong stent patency and reduce ascending bacterial infection by preserving thesphincter of Oddi, but existing evidence is limited to small trials and retrospectiveseries with inconsistent results, and no adequately powered randomized trial hasaddressed high‐grade hilar obstruction.This is an investigator‐initiated, multicenter, open‐label, parallel‐group randomizedcontrolled trial conducted at eight institutions in Taiwan. Patients with unresectableBismuth type II or higher MHBO are randomized 1:1 to suprapapillary or transpapillaryplastic stent placement. Randomization is performed after successful biliary cannulationduring ERCP, using a centralized web‐based system (REDCap) with stratification by site.The primary endpoint is time to recurrent biliary obstruction (TRBO). Secondary endpointsinclude overall survival, technical and clinical success, reintervention rate, andadverse events. Participants are followed until recurrent biliary obstruction, death, orthe end of the study period.