Nuclear Medicine & Radiation Therapy

Radioembolization for Hepatocellular Carcinoma: Evidence-Based Answers to Frequently Asked Questions

Abstract

Bruno Sangro and Mercedes Iñarrairaegui

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related mortality. Radioembolization is a form of selective internal radiation therapy that is increasingly used to treat patients with HCC, particularly those with more advanced disease. This review will try to answer some of the most frequently asked questions regarding the use of radioembolization to treat HCC patients and provide supporting evidence. Rather than a new form of transarterial chemoembolization (TACE), radioembolization is a form of brachytherapy that has a highly localized effect on liver tumors. The two devices that are available (glass and resin microspheres) are similar in size (25 to 35 microns), but differ in the amount of isotope loaded onto each microsphere and the number of spheres injected in a single treatment. Despite this, the evidence seems to indicate that the antitumor effect and safety profiles of these two devices in HCC are similar. Liver cirrhosis frequently underlies HCC. Despite the higher chance for relevant liver toxicity, there is now good evidence from large studies to show that radioembolization can be safely and effectively performed in cirrhotic patients with HCC. With no randomized controlled trials published so far, there is recent scientific evidence that allows comparison between radioembolization and other treatment options including TACE and the systemic, agent sorafenib. Radioembolization appears to have similar efficacy to TACE in patients that are ideal candidates for locoregional therapy and has shown encouraging results in patients that have failed TACE or who are poor candidates for this therapy. Survival in comparable sorafenib- and radioembolizationtreated HCC patients is quite similar. The indication for radioembolization has to be balanced against the risk of liver decompensation and the natural history of the disease, based on tumor burden and liver function. Patients with inadequate liver functional reserve and diffuse tumors affecting either lobes, or portal vein thrombosis that reaches the main trunk should probably not be treated with this procedure.