Comparison Between Radiofrequency Ablation and Hypofractionated Proton Beam Radiation for Recurrent/Residual HCC

Inclusion Criteria: * HCC diagnosed as (i) the presence of risk factors including hepatitis B or C virus and liver cirrhosis, a serum a-fetoprotein (AFP) level greater than 200 IU/ml and a radiologically compatible feature with HCC in one or more CT/MRI/angiograms, or (ii) the presence of risk factors including hepatitis B or C virus and liver cirrhosis, a serum a-fetoprotein (AFP) level less than 200 IU/ml, and a radiologically compatible feature with HCC in two or more CT/MRI/angiograms or (iii) histological confirmation * HCC patients who had recurrent or residual tumor after other treatments * without evidence of extrahepatic metastasis * the largest diameter of tumor should be less than 3cm, and the number of tumor ≤2 * no previous treatment to target tumors by other forms of RT * liver function of Child-Pugh class A or B7 (Child-Pugh score of ≤7) * Age of ≥18 years * performance status of 0 to 2 on the Eastern Cooperative Oncology Group (ECOG) score * WBC count ≥ 2,000/mm3; hemoglobin level ≥ 7.5 g/dL; platelet count ≥ 50,000/mm3; and adequate hepatic function (total bilirubin ≤ 3.0 mg/dL; AST and ALT \< 5.0× upper limit of normal; no ascites) * no serious comorbidities other than liver cirrhosis * written informed consent Exclusion Criteria: * evidence of extrahepatic metastasis * age \< 18 years * liver function of Child-Pugh class B8-9 and C (Child-Pugh score of \>7) or uncontrolled cases of active chronic hepatitis B * previous history of other forms of RT adjacent to target tumors * poor performance status of 3 to 4 on the Eastern Cooperative Oncology Group (ECOG) score * pregnant or breast feeding status * previous history uncontrolled other malignancies within 2 years