Radiosensitizers in hepatocellular carcinoma.

Most hepatocellular carcinoma (HCC) patients present with locally advanced disease with a risk of development of intrahepatic or extrahepatic metastases. Conformal radiotherapy (RT) can be delivered to focal HCCs with sustained local control in selected HCC patients. However, it is frequently not possible to deliver tumoricidal doses to locally advanced HCC due to the risk of radiation-induced liver toxicity or the risk of toxicity to adjacent luminal gastrointestinal organs. Combining RT with radiosensitizers is an attractive strategy to increase the therapeutic ratio for these patients. Clinical experience in combining RT and radiosensitizers in HCC is limited. Hepatic arterial chemoembolization (or transcatheter arterial chemoembolization, TACE) has been used in combination with RT for the treatment of HCC, as have halogenated pyrimidines. More recently, there is a growing experience of RT delivered with molecular targeted agents in HCC. In this review, the rationale for potential radiation sensitization and the clinical experience in HCC for different classes of radiation sensitizers are discussed.