Proton Beam Therapy in Hepatocellular Carcinoma With Portal Vein Tumor Thrombosis

Inclusion Criteria: * Hepatocellular carcinoma (HCC) patients * pathologically proven * HCC diagnosed based on American Association for the Study of Liver Diseases (AASLD) guideline * Portal vein tumor thrombosis (main, first branch, segmental) * Discussion in tumor board including gastroenterologist, radiologist, radiation oncologist * 20 or more age * Eastern Cooperative Oncology Group performance status 0 to 2 within 1 week before participate * Adequate bone marrow function (absolute neutrophil count ≥ 1.0 x 109/l, platelet ≥ 30 x 109/l, hemoglobin ≥ 8 g/dl) * Adequate liver/renal function within 1 week before participate * Child-Pugh class A, B, or early C (score ≤ 10) * Total bilirubin \<3.0 mg/dL, Prothrombin time/International normalized ratio \<1.7, Albumin≥2.8g/dL, Aspartate aminotransferase/alanine aminotransferase\<6 times of upper normal limit * Serum creatinine \< 1,5 x upper normal limit, glomerular filtration rate \> 50 ml/min Informed consent * Women of childbearing potential and male participants must agree to practice adequate contraception while on study and for at least 6 months following the last dose of RT and for at least 28 days following the last dose of sorafenib (whichever is later). Exclusion Criteria: * Uncontrolled hepatic encephalopathy * Previous history of upper abdominal radiotherapy * Status of pregnancy or breast feeding * Less than 12 weeks of expected survival * Uncontrolled ascites * Combined with disease known as radiosensitive disorder (connective tissue disorder, Ataxia-telangiectasia) * Hard to maintain stable respiration less than 5 minutes related with respiratory disease * Combined with uncontrolled severe acute disease other than liver