Abstract
This paper presents the first version of clinical practice guidelines for intrahepatic cholangiocarcinoma (ICC) established by the Liver Cancer Study Group of Japan. These guidelines consist of 1 treatment algorithm, 5 background statements, 16 clinical questions, and 1 clinical topic, including etiology, staging, pathology, diagnosis, and treatments. Globally, a high incidence of ICC has been reported in East and Southeast Asian countries, and the incidence has been gradually increasing in Japan and also in Western countries. Reported risk factors for ICC include cirrhosis, hepatitis B/C, alcohol consumption, diabetes, obesity, smoking, nonalcoholic steatohepatitis, and liver fluke infestation, as well as biliary diseases, such as primary sclerosing cholangitis, hepatolithiasis, congenital cholangiectasis, and Caroli disease. Chemical risk factors include thorium-232, 1,2-dichloropropane, and dichloromethane. CA19-9 and CEA are recommended as tumor markers for early detection and diagnostic of ICC. Abdominal ultrasonography, CT, and MRI are effective imaging modalities for diagnosing ICC. If bile duct invasion is suspected, imaging modalities for examining the bile ducts may be useful. In unresectable cases, tumor biopsy should be considered when deemed necessary for the differential diagnosis and drug therapy selection. The mainstay of treatment for patients with Child-Pugh class A or B liver function is surgical resection and drug therapy. If the patient has no regional lymph node metastasis (LNM) and has a single tumor, resection is the treatment of choice. If both regional LNM and multiple tumors are present, drug therapy is the first treatment of choice. If the patient has either regional LNM or multiple tumors, resection or drug therapy is selected, depending on the extent of metastasis or the number of tumors. If distant metastasis is present, drug therapy is the treatment of choice. Percutaneous ablation therapy may be considered for patients who are ineligible for surgical resection or drug therapy due to decreased hepatic functional reserve or comorbidities. For unresectable ICC without extrahepatic metastasis, stereotactic radiotherapy (tumor size ≤5 cm) or particle radiotherapy (no size restriction) may be considered. ICC is generally not indicated for liver transplantation, and palliative care is recommended for patients with Child-Pugh class C liver function.