1. Purpose of the study

   -To compare stent patency and complication rate between endoscopic ultrasound (EUS) guided stent insertion and endoscopic retrograde cholangiopancreatography (ERCP) guided stent insertion for malignant biliary obstruction

2. Subjects of the study

   -Patients who have biliary obstruction owing to malignant tumors

3. Methods of the study

   • Prospective randomized controlled study
   • Patients were enrolled randomly in two groups, EUS guided stent insertion group or ERCP guided stent insertion group
   • Patients will get assigned procedure (EUS guided stent insertion or ERCP guided stent insertion)for decompression of malignant biliary obstruction
   • After the procedure, regular follow up, blood test,and imaging test will be done to check sufficient biliary decompression,stent patency and complications.

1. Inclusion criteria 1) age: 18 - 80 2) a patients who had common bile duct dilatation because of malignant distal common bile duct obstruction in radiologically 3) Hyperbilirubinemia (total bilirubin >= 1.5 mg/dl) 4) inoperable state 5) a patients who agree to join this study
2. Exclusion criteria 1) a patients who can not endure sedation 2) a patients with bleeding tendency (PT > 1.5 INR, PLT < 50,000) 3) a patients with systemic infection 4) a patients who had hilar obstruction

Inclusion Criteria:

• distal biliary obstruction due to malignant tumor
• unresectable tumor
• Jaundice

Exclusion Criteria:

• Children
• Hilar obstruction
• Active infection
• Bleeding tendency