Aim: We analyzed the effectiveness of external particle radiotherapy (PRT) as an alternative therapy for various stages of hepatocellular carcinoma (HCC).
Methods: Eighty-three patients with HCC underwent PRT in our hospital from 2007 to 2015 (proton beam radiation in 58 patients and carbon ion radiation in 25 patients), including patients with early-stage HCC (single HCC measuring ≤3 cm, Barcelona Clinic Liver Cancer [BCLC] stage 0 or A) (group A, n = 30), those with intermediate-stage HCC (HCCs measuring ≥3 cm but inoperable or multinodular and transcatheter arterial embolization [TACE]-refractory, BCLC stage B) (group B, n = 31), and those with advanced-stage HCC (HCC with portal invasion or extrahepatic metastasis) (group C, n = 22). The median radiation dose was 72.6 GyE (range 50-74) for proton beam radiation and 45.0 GyE (range 45-52.8) for carbon beam radiation. Local control ability was defined as continuous shrinkage of the tumor size without development of new lesions for ≥6 months after PRT.
Results: The rates of local control of the target tumor at 6 months, 1 year, and 2 years were 91.9, 86.3, and 84.8%, respectively. The overall survival rates at 1, 2, and 3 years were 83.0, 65.6, and 55.1%, respectively. Patients in group A showed the best survival rates (100.0% at 1 year and 85.9% at 2 years). The 1-year survival rate was poor in group C (63.6%) despite a good local tumor control rate of 74.7%. The overall survival rates were significantly better in groups A and B than in group C.
Conclusions: The local control rates after PRT were sufficiently high compared to TACE or sorafenib. Thus, PRT should be adopted for patients with difficult-to-treat HCC in the early and intermediate stages.
Keywords: Carbon ion; Hepatocellular carcinoma; Local control; Particle radiotherapy; Proton beam.