Carbon-Ion Radiotherapy for Hepatocellular Carcinoma: Current Status and Future Prospects: A Narrative Review

Because hepatocellular carcinoma (HCC) is a radiosensitive cancer, radiation therapy has been used for the treatment of HCC; however, external beam therapies are currently not described in most of the guidelines for the treatment of HCC. External beam therapies include photon beam therapies and particle beam therapies, which are composed of X-rays or gamma rays and beams of carbon ions or protons, respectively. The focus of this narrative review is carbon-ion radiotherapy (C-ion RT). C-ion RT is well tolerated by elderly patients with HCC and/or sarcopenic patients. In general, a single HCC greater than 30 mm is a good indication for C-ion RT in patients with Child Grade A/B or ALBI Grade 1/2. The local control rates and overall survival rates at 5 years after C-ion RT for HCCs larger than 30 mm are excellent, with fewer adverse events, such as radiation-induced liver damage. Advanced HCC with portal vein tumor thrombus is also an indication for C-ion RT in certain selected patients. C-ion RT is a promising therapeutic option for patients with HCC.