Evolving Role of Radiopharmaceuticals in Hepatocellular Carcinoma Treatment

The global incidence of primary liver cancer has been increased during recent decades. Among the primary liver malignancies, hepatocellular carcinoma (HCC) is recognized as the most prevalent and aggressive. Although HCC has come to be regarded as a radioresponsive tumor during the last decade, it has also been noted that the ability to deliver destructive radioactive doses exclusively to HCC is limited with conventional external irradiation techniques. This review examines a number of radiotherapeutic techniques used to treat HCC, and the radiopharmaceuticals associated with those techniques. Selective internal radiotherapy (SIRT) is a powerful therapeutic technique developed during recent decades that is increasingly used in HCC treatment due to its superior ability to target and destroy cancer cells while sparing normal tissue. The radiopharmaceuticals used in SIRT are usually comprised of a simple ion and a complex or a carrier. Transarterial radioembolization (TARE) is a technique that is increasingly used in adjuvant or neoadjuvant therapy following the surgical treatment of HCC, as well as the treatment of unresectable or untransplantable HCC. The primary radiopharmaceuticals used in TARE include Iodine- 131-labeled Lipiodol and Yttrium-90 microspheres. Radioimmunotherapy (RAIT) is currently used as targeted procedure for adjuvant therapy and combination therapy of HCC. The primary radiopharmaceutical used in RAIT is 131I-metuximab. Interstitial brachytherapy has also been the subject of recent HCC treatment investigations. The primary radiopharmaceuticals used in interstitial brachytherapy are implanted iodine-125 seed strands. This review surveys the important milestones in the development and clinical implementation of the radiopharmaceuticals used in HCC therapy and critically examines new and emerging trends for the delivery of radiopharmaceuticals to HCC tissues.