Transarterial Therapy for Neuroendocrine Tumors: Protocol for a Systematic Review and Network Meta-analysis
Authors: Bassir Ali , Konstantinidis Menelaos , Moon John T. , Tran Andrew , Chockalingam Arun , Ferreira Katya , Ludeman Emilie , Habibollahi Peiman , Geschwind Jeff F. , Nezami Nariman 
Published: November 2022

ABSTRACTIntroductionNeuroendocrine neoplasms are a form of tumor that develops from a variety of neuroendocrine cell types and is most commonly found in the gastrointestinal tract. As the blood from the GI tract drains into the liver, it frequently metastasizes there. Intraarterial therapies, such as bland transarterial embolisation, conventional transarterial chemoembolisation, drug-eluting beads transarterial chemoembolisation, and transarterial radioembolization with yttrium-90 are advanced methods for limiting the burden of neuroendocrine liver metastasis tumors. Currently, there is no study that compares all of these methods. Our goal is to compare the efficacy and harm of each of transarterial therapies for stage IV neuroendocrine neoplasms by conducting this systematic review and network meta-analysis.Methods and AnalysisWe will search electronic databases (MEDLINE, Cochrane, Embase, Scopus,ClinicalTrials.gov) from their inception to November 2022 to find all studies that compare survival and clinical finding between any two of the following intraarterial interventions: bland transarterial embolisation, conventional transarterial chemoembolisation, drug-eluting beads transarterial chemoembolisation, and transarterial radioembolization, the latter with yttrium-90. We will include randomized controlled trials (RCT), cluster-RCTs, and observational studies. We will investigate selected articles regarding our primary outcomes (Overall survival, Progression-free survival, death) and also our secondary outcomes (post embolization syndrome, hepatic abscesses, hepatic failure, gallbladder necrosis, non-target embolization). We will also search trial registries and the references of included studies to identify any additional published or unpublished studies for possible inclusion. Risk of bias will be assessed using the tools developed by Cochrane (i.e., the Cochrane RoB 2 tool for RCTs and cluster RCTs, and ROBINS-I for observational studies). We will conduct frequentists network meta-analyses, and we will use the Confidence in Network Meta-Analysis tool to assess the confidence in the evidence for the primary outcomes.Ethics and DisseminationWe seek to publish our findings through peer review with a high impact, and readers will have access to the data gathered in this study. Because the underlying research is based on systematic evaluations of available data, it does not require approval by an ethical review board. The systematic review and meta-analysis’s findings will also be presented at various conferences and seminars.Strengths and LimitationsThis meta-analysis can be used to compare different types of intraarterial therapies for NELM, which can serve as a guide for choosing the best treatment option for non-surgical candidates.This research will lay the groundwork for future clinical trials comparing these therapy options, which can guide clinicians with a greater degree of certainty.Variations in specific therapy, like differences in medications used for intervention, may not be considered and may affect this comparison.