Advances in selective internal radiotherapy for primary and secondary liver cancer

Liver metastases are the leading cause of death from colorectal cancer (CRC) with a median survival of 19 months when treated with chemotherapy. The increasing incidence of hepatocellular carcinoma and the poor outcomes for intrahepatic cholangiocarcinoma (ICC) also add to the clinical need to develop effective liverdirected treatment strategies. Surgical approaches have led to prolonged disease control with five-year overall survival rates of over 50%, although only 15-20% of patients presenting with liver metastases are considered resectable. Non-surgical therapies offer the potential for improved disease control. These techniques include microwave and radiofrequency ablation, selective internal radiation therapy (SIRT), trans-arterial chemoembolisation (TACE), bland transarterial embolisation and stereotactic ablative body radiotherapy (SBRT). Recent guidance from NICE compares SIRT and TACE for HCC stating that, in non-randomised series, SIRT has higher response rates and survival outcomes (NICE, MIB 62, 63 2016). In the NHS England Commissioning through Evaluation programme, SIRT is offered to patients with inoperable ICC and patients with advanced CRC who have failed two lines of chemotherapy or are intolerant to chemotherapy. The recently published SIRFLOX clinical trial compared chemotherapy alone with chemotherapy combined with SIRT in the first-line treatment of metastatic CRC. This study reported an improvement in hepatic progression free survival (PFS) of 7.9 months in patients receiving SIRT, although it failed to reach the primary endpoint of PFS. The safety profile for the combination of SIRT with chemotherapy was as expected and as previously reported, including the safety of hepatic resection following SIRT. The evidence from this study will be further augmented by the pooled analysis of SIRFLOX, FOXFIRE and FOXFIRE Global; overall survival will be reported in 2017 and this will represent outcome data from over 1,000 patients.