Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Jan 15, 2017; 9(1): 4-20
Published online Jan 15, 2017. doi: 10.4251/wjgo.v9.i1.4
New therapeutic approaches to metastatic gastroenteropancreatic neuroendocrine tumors: A glimpse into the future
Esther Una Cidon
Esther Una Cidon, Department of Medical Oncology, Royal Bournemouth Hospital, Bournemouth, Dorset BH5 2AZ, United Kingdom
Author contributions: Una Cidon E designed and performed the research and wrote the paper.
Conflict-of-interest statement: Nothing to disclose.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Esther Una Cidon, MD, PhD, Medical Oncologist, Department of Medical Oncology, Royal Bournemouth Hospital, Castle Lane East, Castle Ln E, Bournemouth BH5 2AZ, United Kingdom.
Telephone: +44-01202-705156 Fax: +44-01202-704789
Received: June 28, 2016
Peer-review started: June 29, 2016
First decision: August 26, 2016
Revised: October 13, 2016
Accepted: November 21, 2016
Article in press: November 22, 2016
Published online: January 15, 2017

Neuroendocrine (NE) gastroenteropancreatic tumors are a heterogeneous group of neoplasias arising from neuroendocrine cells of the embryological gut. Their incidence have increased significantly over the past 3 decades probably due to the improvements in imaging and diagnosis. The recent advances in molecular biology have translated into an expansion of therapeutic approaches to these patients. Somatostatin analogs, which initially were approved for control of hormonal syndromes, have recently been proven to inhibit tumor growth. Several new drugs such as antiangiogenics and others targeting mammalian target of rapamycin pathways have been approved to treat progressive pancreatic neuroendocrine tumors (NETs) although their role in non-pancreatic is still controversial. The treatment of NETs requires a coordinated multidisciplinary approach. The management of localized NETs primarily involves surgical resection followed by surveillance. However, the treatment of unresectable and/or metastatic disease may involve a combination of surgical resection, systemic therapy, and liver-directed therapies with the goal of alleviating symptoms of peptide release and controlling tumor growth. This article will review the current therapeutic strategies for metastatic gastroenteropancreatic NETs and will take a glimpse into the future approaches.

Keywords: Gastroenteropancreatic neuroendocrine tumors, Peptide receptor radionuclide therapy, Somatostatin analogs, Octreotide, Transarterial chemoembolization, Carcinoid syndrome, Setotonin, Chromogranin

Core tip: The management of localized NETs is straight forward, however, the treatment of advanced tumors involves several disciplines and requires a coordinated multidisciplinary approach. Recent advances in molecular biology have expanded the therapeutic arsenal. Somatostatin analogs, initially approved for control of hormonal syndromes, have recently proven to inhibit tumor growth. Several new drugs, antiangiogenics, mTOR inhibitors have been tested with promising results and some of them have already been approved. Several trials are still under way but the future should focus on patient selection, predictive markers, and tolerability improvement as critical aspects to continue advancing.