Study Protocol for a Trial: A Single-Arm, Open-Labeled Study Evaluating Transcatheter Arterial Embolization Plus Everolimus Combination Therapy for Patients With Liver Metastasis of Gastroenteropancreatic Neuroendocrine Tumors

Background: The number of patients with non-functional neuroendocrine tumors (NETs) has increased recently, and the rate of liver metastasis of NETs is about 20% in patients at the first diagnosis. Transcatheter arterial embolization (TAE) and everolimus are therapies with reported efficacy, but few reports have described their combined treatment. We therefore aim to evaluate the efficacy and safety of combination therapy with everolimus and TAE in patients with liver metastasis of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in a prospective study. Methods: We design a single-arm, open-label, prospective study to evaluate the efficacy and safety of combination therapy with everolimus and TAE in patients with liver metastases of GEP-NETs. The study started in June 2021 at Okayama University Hospital and is expected to enroll 18 patients over a 2-year period. Discussion: This study is a prospective study investigating a new treatment method for a rare disease called GEP-NETs. We may obtain useful information that contributes to the treatment guidelines in this study. However, NET is a rare disease, and although the number of cases is statistically established, it may not be possible to accurately assess causality.