This prospective cohort is comprised of patients with malignant biliary obstruction caused by hepatocellular carcinoma who were treated with endoscopic biliary drainage using fully covered self expandable metal stent.

After selective cannulation of the bile duct, cholangiography is obtained using contrast agent.

A guide wire is passed through the stricture, and then fully-covered metal stent is inserted under fluoroscopy guidance during ERCP.

Clinical success rate is defined as a reduction of total bilirubin level above 50% or total bilirubin level less than 2 mg/dL within 1 month after the procedure. Clinical success rate of all procedures will be measured.

Technical success is defined as whether the stent is properly inserted into the stricture site and the bile or contrast agent is drained. Technical success rate of all procedures will be measured.

Stent patency duration is defined as number of days between immediately after procedure and occurrence of stent dysfunction.

Stent migration is divided in two types. Proximal dislocation is defined as the movement of the stent into the bile duct at the site of obstruction, and distal dislocation is defined as the distal displacement of the stent from the stenotic site (including cases where the stent is not observed due to self-removal). The rate of stent migration including both proximal and distal dislocation will be measured.