Two-fraction carbon ion radiotherapy for hepatocellular carcinoma: Preliminary results of a phase I/II clinical trial

Abstract

4124 Background: We reported that the 4-fraction/1-week carbon ion radiotherapy, that had been conducted from April 2001 to February 2003 within a phase II clinical study, appeared to be safe and to have a promising potential as a new, radical, and minimally invasive therapeutic option for hepatocellular carcinoma (HCC) at the last ASCO annual meeting. The next clinical trial of 2-fraction/2-day carbon ion radiotherapy is going on within a phase I/II study from April 2003. Patients and Methods: Twenty-five patients with histologically proven HCC were treated with 2-fraction/2-day carbon ion radiotherapy of 32.0GyE in 6, 33.6GyE in 7, 35.2GyE in 6, and 37.0GyE in 6 in a step-wise dose-escalation study from April 2003 to August 2004. Common Toxicity Criteria, RTOG/EORTC criteria were used for evaluation of toxicity. Serial changes in Child-Pugh score were investigated after the start of therapy to evaluate its invasiveness to the liver. Anti-tumor effect was evaluated by the tumor response and directly- calculated local control rate. Results: During a median follow-up of 12.1 (3.9–19.5) months, no severe adverse effects and no treatment-related deaths occurred. In the early phase, no change in the Child-Pugh score was observed in 79% (19/24), only a 1-point increase in 17% (4/24), and 2-point increase in 4% (1/24) of the patients. In the late phase, similar observations were made in 75% (12/16), 6% (1/16), and 19% (3/16), respectively. The overall tumor response rate was 96% (24/25) at 6 months after the therapy. Local control rates were 96% (24/25) and 93% (13/14) at 6 and 12 months, respectively. Overall survival rates were 100% at 6 and 12 months, respectively. There were preliminarily no differences between the results in the current study and those in the 4-fraction carbon ion radiotherapy. Conclusion: Two-fraction carbon ion radiotherapy for HCC appears preliminarily to be safe and effective. However, further observation is needed to confirm its clinical usefulness. No significant financial relationships to disclose.