The Role of Interventional Radiology for the Treatment of Hepatic Metastases from Neuroendocrine Tumor: An Updated Review

Abstract

Interventional radiology plays an important role in the management of patients with neuroendocrine tumor liver metastasis (NELM). Transarterial embolization (TAE), transarterial chemoembolization (TACE), and selective internal radiation therapy (SIRT) are intra-arterial therapies available for these patients in order to improve symptoms and overall survival. These treatment options are proposed in patients with NELM not responding to systemic therapies and without extrahepatic progression. Currently, available data suggest that TAE should be preferred to TACE in patients with NELM from extrapancreatic origin because of similar efficacy and better patient tolerance. TACE is more effective in patients with pancreatic NELM and SIRT has shown promising results along with good tolerance. However, large randomized controlled trials are still lacking in this setting. Available literature mainly consists in small sample size and retrospective studies with important technical heterogeneity. The purpose of this review is to provide an updated overview of the currently reported endovascular interventional radiology procedures that are used for the treatment of NELM.

Keywords: brachytherapy; chemoembolization; embolization; neoplasm metastasis; neuroendocrine tumors.

Figure 1

Schematic representation of hepatic vascularization with comparison between normal hepatocytes and liver metastases.

Figure 2

A 71-year-old woman with neuroendocrine tumor from undefined primary and liver metastases with important carcinoid syndrome and liver pain related to diffuse liver involvement. Pre-embolization diffusion-weighted magnetic resonance (MR) image in the axial plane, (A), T1-weighted MR image after intravenous administration of a gadolinium chelate during the arterial phase without (B) and with subtraction (C) show multiple, bilateral liver metastases with restricted diffusion (arrows), and hyperenhancement during the arterial phase (arrows). Patient had 6 sessions of conventional transarterial chemo-embolization under general anesthesia using a mixture of iodized oil (Lipiodol^®) and doxorubicin and final embolization using calibrated 300–500 µm microspheres. Initial angiogram of right anterior hepatic artery shows multiple arterial tumor blush (arrows) (D) and final angiogram shows proximal occlusion of the right anterior hepatic artery (arrow) (E). Post-embolization diffusion-weighted MR image in the axial plane (F), T1-weighted MR images obtained after injection of gadolinium chelate during the arterial phase without (G) and with subtraction (H) show multiple, bilateral liver metastases with restricted diffusion (arrows), and hypointensity of most of metastases during the arterial phase (arrows).

Figure 3

An 80-year-old woman midgut neuroendocrine tumor grade I (Ki67 = 1%), treated 10 years ago with surgery. She had an exacerbation of symptoms resistant to octreotide. MRI examination obtained before selective internal radiation therapy (SIRT) shows a single, hyperintense, and heterogeneous metastasis of the right liver (arrow) on T2-weighted image (A), marked diffusion restriction on high b-value diffusion-weighted image (arrow) (B), and heterogeneous enhancement on T1-weighted MR image obtained after intravenous administration of a gadolinium chelate during the arterial phase (arrow) (C). Arteriogram of common hepatic artery shows two feeding arteries (arrows) originating from the right branch of the hepatic artery (arrowhead). The injection point was defined 15 mm upstream to arterial bifurcation (D). Pre-treatment scintigraphy after injection of macroaggregated albumin labeled with 99m-Technetium shows an important uptake by metastasis (arrow), a low uptake by adjacent healthy liver, and no non-target embolization (E). Post-SIRT scintigraphy confirmed these results, with uptake by metastasis (arrow) (F). One year after SIRT, MRI shows a decrease in lesion size (2.5 versus 6 cm) (arrow), on T2-weighted image (G), a decrease in diffusion restriction (arrow) (H), and no more hyperenhancement on T1-weighted MR image after injection of a gadolinium chelate during the arterial phase (arrow) (I). Patient has no recurrent disease during the first two years after SIRT. Then, she had a complementary treatment by lutetium Lu 177 DOATATE (Lutathera^®, Novartis, Basel, Switzerland). She is still alive to date.