Carbon Ion Radiotherapy for the Treatment of Hepatocellular Carcinoma

The treatment of hepatocellular carcinoma (HCC) associated with underlying chronic liver diseases should include every possible effort to maintain optimal liver function. Charged particle therapy using proton and carbon ion beams provides a sharper and more focused irradiation to the target region of the liver than conventional X-ray radiotherapy. It therefore reduces the risk of tratment-related liver damage. A series of four clinical studies of carbon ion radiotherapy for the treatment of HCC were conducted at the National Institute of Radiological Sciences from June 1995 to Augst 2005. These studies determined the optimal doses for radiotherapy for HCC. We also contributed to reducing the number of irradiation sessions, and achieved a shorter treatment period. The treatment schedule was simplified from 15 fractions over five weeks to two fractions for two days. The local control rates for the carbon ion radiotherapy were around 90% across various tumor sizes, tumor locations, and fractionations schedule. In most of the patients, the liver function showed no or a minor deterioration. Heavy charged particle therapy, which provides a safe and powerful therapeutic modality for tumors of all sizes, is an excellent choice for the treatment of HCC. It can be used effectively in conjunction with other approaches available in multidisciplinary disease management.