Role of hepatic intra-arterial therapies in metastatic neuroendocrine tumours (NET): guidelines from the NET-Liver-Metastases Consensus Conference

OBJECTIVES: Liver metastasis from a neuroendocrine tumour (NET) represents a significant clinical entity. A multidisciplinary group of experts was convened to develop state-of-the-art recommendations for its management. METHODS: Peer-reviewed published reports on intra-arterial therapies for NET hepatic metastases were reviewed and the findings presented to a jury of peers. The therapies reviewed included transarterial embolization (TAE), transarterial chemoembolization (TACE) and radioembolization (RE). Two systems were used to evaluate the level of evidence in each publication: (i) the US National Cancer Institute (NCI) system, and (ii) the GRADE system. RESULTS: Eighteen publications were reviewed. These comprised 11 reports on TAE or TACE and seven on RE. Four questions posed to the panel were answered and recommendations offered. CONCLUSIONS: Studies of moderate quality support the use of TAE, TACE and RE in hepatic metastases of NETs. The quality and strength of the reports available do not allow any modality to be determined as superior in terms of imaging response, symptomatic response or impact on survival. Radioembolization may have advantages over TAE and TACE because it causes fewer side-effects and requires fewer treatments. Based on current European Neuroendocrine Tumor Society (ENETS) Consensus Guidelines, RE can be substituted for TAE or TACE in patients with either liver-only disease or those with limited extrahepatic metastases.