Selective internal radiation therapy (SIRT; micro-brachytherapy or ‘radio-embolisation’) is used for the treatment of non-resectable hepatic metastases secondary to colorectal cancer, with limited or no extrahepatic disease. It may be used alone or in combination with chemotherapy. It aims to deliver radiation directly into the metastases, minimising the risk of radiation damage to healthy surrounding tissues. Under local anaesthesia, glass or resin microspheres containing a small radioactive source (yttrium-90) designed to embolise into small vessels around the metastases, are injected into branches of the hepatic artery (usually via a percutaneous femoral approach). In this way the microspheres can be selectively injected directly into the tumour within the liver, delivering high doses of localised ionising radiation.

NICE has issued an interventional procedure guidance in July 2011 for the use of selective internal radiation therapy for non-resectable colorectal metastases in the liver. The guidance states that colorectal cancer is a common cancer. It generally occurs in people older than 50 years of age, with the risk increasing with age.

This review summarises the NICE guidance.