A Comparison of a Fully Covered Self-expandable Metal Stent With an External Anchoring Plastic Stent and Uncovered Stent

Inclusion Criteria: * Adults with 19 years of age or older * Those who voluntarily consented to the trial and signed a written consent * Inoperable malignant biliary obstruction Exclusion Criteria: * Previous surgical biliary drainage * Patients continuosly requiring percutaneous transhepatic biliary drainage * History of biliary drainage with metal stent * Biliary obstruction located in hilum or intrahepatic duct * Patients with life expectancy of 3 months or less * On pregnancy * Unable to underwent endoscopic procedures