The study aim to evaluate the efficacy of intraductal radiofrequency ablation for unresetable hilar cholangiocarcinoma in addition to biliary stenting. The patient would be randomized into 1:1 ratio of conventional group who received biliary stenting alone, and RFA group who receive intraductal RFA before biliary stenting. Immediate complications as well as long term stent patency and patient survival would be studied.

Study design: randomized single-blind control trial Study population: patient with unresectable hilar cholangiocarcinoma with obstructive jaundice who need hilar biliary stenting Primary endpoint: Biliary stent patency time Secondary endpoint: Patient survival Intervention

1. Recruited patients randomly assigned into 2 groups, conventional and RFA group by sealed enveloped
2. All patients receive endoscopic biliary stenting. Those in RFA group receive RFA before biliary stent.
3. Monitor for adverse event during hospitalization and during follow up
4. Follow up as outpatient in 4-weekly interval with monitoring of serum liver function test as routine

Inclusion Criteria:

• Hilar cholangiocarcinoma diagnosed by imaging or pathology
• Considered unresectable or unfit for surgery
• Presence of obstructive jaundice need endoscopic biliary drainage

Exclusion Criteria:

• History of unremovable metallic biliary stent placement
• severe biliary stricture that the instrument was unable to pass through
• unfit for endoscopic under conscious sedation
• loss to follow up and loss contact within 6 months after intervention