Recent Trends for Management of Carcinoid Tumour of the Gastrointestinal Tract

Abstract

Carcinoid tumors are rare, slow growing neuroendocrine tumors arising from the enterochromaffin Cells disseminated throughout the gastrointestinal tract. Cells found throughout the crypts of Lieberkuhn of the gut, and bronchopulmonary systems. They secrete serotonin and serotonin precursors. The incidence rates were 2.47: 4.48 for men and 2.58: 3.98 for women per 100,000 populations per year. Carcinoids form intramural grey firm nodules, masses or they may protrude into the lumen as polypoid nodules. Because of their inconspicuous size and submucosal location, primary carcinoid tumors are rarely diagnosed before metastasis. In most instances, they are discovered incidentally at the time of surgery for other abdominal disorders, and their presence may be undetectable for years without obvious signs or symptoms. Their clinical diagnosis includes feed ingrelated or crampy abdominal pain, cessation of diarrhea, a palpable abdominal mass and weight loss. Carcinoid syndrome (Cs) occurs when cells from the tumor metastasize to the liver and vasoactive substances enter systemic circulation via the hepatic vein. The laboratory diagnosis includes recent advances in genetics, molecular biology, histopathology, biochemical markers (Chromogranin A (CgA) represents a general neuroendocrine marker, important in not only diagnostic procedures but also in follow up of patients, 5-hydroxyindole acetic acid (5-HIAA is a useful alternative when screening for carcinoid tumors), Catecholamines, Ki67 expression or antibody levels can be useful if chemotherapy is a consideration and Tachykinins). Radiologic investigation includes Conventional barium studies (this type of study is often useful in diagnosing some GI carcinoid tumors), Computed tomography, Magnetic resonance imaging (MRI is considered superior to CT for lesion assessment in the solid visceral organs), Radionuclide scans. Scans using small amounts of radioactivity and special cameras may be helpful in looking for carcinoid tumors (111In-Pentetreotide Scintigraphy, MIBG Scintigraphy). Positron emission tomography (PET) is another imaging test that uses low levels of radioactivity to look for tumors. Another important modality is endoscope of gastrointestinal carcinoid tumors. The treatment alternatives in patients with disseminated GEP-NETs include debulking surgery, Laser Interstitial Thermotherapy (to create coagulative necrosis has been proposed for the management of hepatic metastasis from NETs under MRI guidance), somatostatin receptor (SSTR)-mediated radiation therapy besides medical treatment with somatostatin analogues. Interferon (IFN- α)