Stereotactic Ablative Radiotherapy for Hepatocellular Carcinoma ≤ 5 cm

Inclusion Criteria: * Male or female patients ≥ 20 years of age * Initially diagnosed or recurrent hepatocellular carcinoma (HCC) * Unresectable HCC * Cirrhotic status of Child Pugh class A or B7 * Eastern Cooperative Oncology Group performance status 0 or 1 * single or sum of multiple tumor ≤ 5 cm * HCC with 3 cm apart from gastrointestinal tract * The volume of uninvolved must be at least 700 ml * Incomplete response after trans-arterial chemo-embolization of 1-5 * A single lesion or multiple lesions including portal vein tumor thrombosis included in radiation field with one or consecutive sessions of stereotactic body radiation therapy (SBRT) * No evidence of an uncontrolled lesion at any other site * No evidence of complications of liver cirrhosis * No evidence of uncontrolled inter-current illness * Patient or guardian must be able to provide verbal and written informed consent Exclusion Criteria: * Patient with previous history of abdominal radiation * Direct invasion to esophagus, stomach or colon by HCC