Radioembolization for primary and metastatic liver cancer

The incidence of hepatocellular carcinoma is increasing. Most patients present beyond potentially curative options and are usually affected by underlying cirrhosis. In this scenario, transarterial therapies, such as radioembolization, are rapidly gaining acceptance as a potential therapy for hepatocellular carcinoma and liver metastases. Radioembolization is a catheter-based liver-directed therapy that involves the injection of micron-sized embolic particles loaded with a radioisotope by use of percutaneous transarterial techniques. Cancer cells are preferentially supplied by arterial blood and normal hepatocytes by portal venous blood; therefore, radioembolization specifically targets tumor cells with a high dose of lethal radiation and spares healthy hepatocytes. The antitumor effect mostly comes from radiation rather than embolization. The most commonly used radioisotope is yttrium-90. The commercially available devices are TheraSphere (glass based; MDS Nordion, Ottawa, Canada) and SIR-Sphere (resin based; Sirtex, Lane Cove, Australia). The procedure is performed on an outpatient basis. The incidence of complications is comparatively less than other locoregional therapies and may include nausea, fatigue, abdominal pain, hepatic dysfunction, biliary injury, fibrosis, radiation pneumonitis, gastrointestinal ulcers, and vascular injury. However, these complications can be avoided by meticulous pretreatment assessment, careful patient selection, and adequate dosimetry. This article focuses on both the technical and clinical aspects of radioembolization with emphasis on patient selection, uses and complications.