Management of Gastrointestinal Carcinoid Tumors: An Overview

Abstract

Gastrointestinal Carcinoid Tumors are neoplasms that originate in the lining of the gastrointestinal (GI) tract and are derived from the neuroendocrine cells. It is rare for these tumors to be detected before they develop metastases, and they are often discovered incidentally during surgery for other abdominal conditions. Currently, various treatment options are available for managing these tumors, such as surgery, which is usually the most effective treatment. The type of surgery depends on several factors, including the size and location of the tumor, the patient's comorbidities, and the presence of carcinoid syndrome. As a result of the low probability of metastasizing, surgery is typically the best treatment option for neuroendocrine tumors of type I. NETs of type II and III are the most aggressive and require a formal gastrostomy, whereas NETs of type IV are treated with local ablation or cytotoxic chemotherapy. The first line of pharmacological treatment is somatostatin analogs (SSAs); they inhibit hormone production and tumor cell proliferation by binding to G-protein-coupled somatostatin receptors (SSTRs). Another option is Telotristat, which inhibits tryptophan hydroxylase - 1 (TPH-1) in the digestive tract, thereby reducing serotonin production. The treatment of patients with carcinoid syndrome who are refractory to SSAs could be improved by peptide receptor radionuclide therapy (PRRT), which uses radiolabeled somatostatin analogs to target overexpressed somatostatin receptors in well-differentiated NETs.