Comparison of efficacy and safety of short-course carbon ion radiotherapy for patients with hepatocellular carcinoma depending on the histological differentiation

Background/aims: To compare the efficacy and safety of the short-course carbon ion radiotherapy (C-ion RT) for hepatocellular carcinoma (HCC) in terms of tumor histological differentiation. Methods: The study consisted of 63 patients undergoing C-ion RT of 52.8 GyE in 4 fractions between April 2000 and March 2003. Eligibility criteria were as follows: biopsy-proven HCC; recurrent or residual tumor after other ineffective treatments or no indication for any other treatment; no tumor thrombosis of main trunk of portal vein; no other viable lesion outside the planning target volume; no prior radiotherapy for target tumors; hepatic disorder of Child-Pugh classification A or B; ECOG performance status of 0-2; no other active cancer; and digestive tract not in contact with clinical target volume. Maximum tumor diameter was 4.0cm (range 1.2-12.0 cm). Four were well differentiated tumor, 2 were well to moderately-differentiated, 51 were moderately differentiated, 4 were moderately to poorly-differentiated, and 2 were poorly differentiated. The total dose delivered was 52.8 GyE in 4 fractions for 1 week. The dose per fraction was 13.2 GyE. Results: The 5-year local control rates were 100.0% in the well differentiated group, 96.0% in the moderately differentiated group, 83.3% in the poorly differentiated group, respectively. The 5-year overall survival and cause-specific survival rates were 33.3% and 33.3% in the well differentiated group, 23.4% and 32.8% in the moderately differentiated group, and 25.0% and 25.0% in the poorly differentiated group, respectively. There were no significant differences (P = 0.710, P = 0.977, respectively). Further, there were no significant differences in late liver toxicity, and no hepatic failure resulting from the therapy and no treatment-related death occurred. Conclusions: Excellent local control was obtained independent of tumor histological differentiation. Short-course C-ion RT appears to be an effective and safe treatment modality for all histological type of HCC. Outcomes after short-course carbon ion radiotherapy for patients with hepatocellular carcinoma according to tumor size.The 21st Conference of the Asian Pacific Association for the Study of the Live