Cholangiocarcinoma is the primary malignant tumor of the bile ducts which originates from cholangiocytes. 1 Surgical resection is the only curative therapy. Unfortunately, due to lack of symptoms until late in the disease, the majority of patients present with unresectable disease, typically resulting in advanced cholangiocarcinoma at the time of diagnosis. In addition, advanced age, poor performance status, acute illness, and/or systemic disease are considered inoperable in many cases. 2,3 In particular, in hilar cholangiocarcinoma, primary invasion of the portal vein and metastasis to the hepatic lobes occurs so frequently that surgical resection is impossible, and it is associated with a poor prognosis. 4 Biliary