CIO 2021-38 Transarterial Embolization of Neuroendocrine Metastases: Patient Selection, Procedural Techniques, and Follow-Up Imaging

Purpose: Neuroendocrine tumors account for 1.5% of gastrointestinal and pancreatic neoplasms. Hepatic metastases may be seen in up to 93% of patients. Metastases are hormonally active and lead to hepatic dysfunction due to replacement of normal parenchyma. Transarterial embolization is a safe and effective strategy to mitigate symptoms related to hormone excess and improve overall survival. Cases from our institution are used to review techniques and considerations for hepatic arterial embolization of neuroendocrine tumor metastases. Patient selection, preprocedural imaging, technical approaches, and postprocedural care including follow-up imaging are discussed.

Material and Methods: Initial and follow-up imaging can be performed with computed tomography, magnetic resonance imaging, or nuclear imaging. Angiography is used during the procedure allows for visualization of vascular tumors and assessment of stasis or near-stasis. CT is useful for both detection of primary tumor and assessment for metastatic disease, particularly when an enterography protocol is used to distend the bowel lumen. MRI can be used for baseline evaluation of metastatic disease and follow-up.

Results: Selection for transarterial embolization includes assessment of tumor burden, hepatic function, portal vein patency, and hepatic arterial anatomy. Hepatic arterial anatomy and portal vein patency are confirmed intra-procedurally with angiography of the celiac artery and superior mesenteric artery to evaluate for replaced or accessory hepatic arterial vasculature and confirm patency of the portal venous system. The end goal of embolization is stasis or near stasis of flow within the hepatic arterial vasculature. Embolization may be performed bland or in conjunction with chemotherapy or radiofrequency ablation. After embolization, patients are admitted to the hospital to monitor hepatic function, manage postembolization syndrome, and monitor for surge of hormone release. Follow up imaging is obtained three months, six months, and a year after embolization. Repeat embolization is performed when there is clinical or biochemical evidence of increasing hormone release or hepatic dysfunction.

Conclusions: Transarterial embolization is a safe and effective treatment strategy for hepatic metastatic disease related to neuroendocrine tumors and leads to both symptomatic relief and improved survival.