The authors have published a series of studies evaluating the safety and efficacy of proton beam therapy for the treatment of hepatocellular carcinoma in a variety of clinical settings. In the current study, they retrospectively reviewed their entire experience treating hepatocellular carcinoma patients with proton beam therapy at their hospital-based facility at the University of Tsukuba.

From November 2001 to December 2007, 333 patients with hepatocellular carcinoma were treated with proton beam therapy at the University of Tsukuba. A total of 318 patients were included in this study. Total dose delivered and fractionation scheme were determined by protocols that varied based on location of tumor. Survival rates and prognostic factors were assessed.

Overall actuarial survival rates at 1-year, 3-years, and 5-years were 89.5% (95% confidence interval [95% CI], 85.7-93.1%), 64.7% (95% CI, 56.6-72.9%), and 44.6% (95% CI, 29.7-59.5%), respectively. Child-Pugh liver function (hazards ratio [HR], 2.84; P < .01), T stage (HR, 1.94; P < .05), performance status (HR, 2.12; P < .01), and planning target volume (HR, 2.12; P < .05) significantly impacted survival. The 3-year and 5-year survival rates were 69.1% (95% CI, 59.9-78.3%) and 55.9% (95% CI, 41.5-70.3%), respectively, for patients with Child-Pugh A disease and 51.9% (95% CI, 32.3-71.5%) and 44.5% (95% CI, 23.1-65.8%), respectively, for patients with Child-Pugh B disease. The actuarial survival rates of patients with Child-Pugh class A were statistically different between groups of planned target volume 125 mL (P < .05).

The authors have shown proton beam therapy to be both safe and effective for the treatment of patients with hepatocellular carcinoma. They strongly recommend the consideration of proton beam therapy in patients for whom other treatment options are risky or contraindicated.