Neuroendocrine tumors of the gastro-entero-pancreatic system

Abstract

Gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms, although their prevalence has increased substantially over the past three decades. Moreover, there has been an increased clinical recognition and characterization of these neoplasms. They show extremely variable biological behavior and clinical course. Most NETs have endocrine function and secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome; however, many are clinically silent until late presentation with mass effects. Investigation and management should be individualized for each patient, taking into account the likely natural history of the tumor and general health of the patient. Management strategies include surgery for cure or palliation, and a variety of other cytoreductive techniques, and medical treatment including chemotherapy, and biotherapy to control symptoms due to hormone release and tumor growth, with somatostatin analogues (SSAs) and alphainterferon. New biological agents and somatostatintagged radionuclides are under investigation. Advances in the therapy and development of centers of excellence which coordinate multicenter studies, are needed to improve diagnosis, treatment and therefore survival of patients with GEP NETs.

Clinicopathological and Prognostic Analysis of Neuroendocrine Carcinoma of The Colorectum

“…In addition to having the same biological characteristics as malignant colorectal tumors, neuroendocrine carcinoma of the colorectum also had the synthesis, storage and secretion function of peptide and/or amine hormones, which could cause symptoms of corresponding endocrine disorders [14,15]. However, in clinical work obvious symptoms of endocrine disorders could be found in only 1.6% of the patients, most of whom had tumors at an advanced stage [16]. The reasons for that might include: 1) the active substances produced by the tumor were not sufficient to have a significant impact on target organs; 2) the active substances produced by the tumor were quickly degraded in the peripheral blood; 3) the substances secreted by the tumor were probably hormone precursors whose biological activity was lower than that of its end-product; and/or 4) the tumor secreted some substances that could inhibit hormone activity [17].…”

Carcinoma-like nonfunctional pheochromocytoma in the right adrenal gland: A case report

“…NETs originate from neuroendocrine cells, and the overproduction of hormones within the tumor results in characteristic symptoms, which are dependent on the unique effect of each hormone (2). NETs have been considered as malignant tumors as they are able to metastasize long after treatment (10). However, a number of different organ-specific diagnostic systems have been developed for each NET origin; therefore, the staging and grading of NETs remains unclear (11).…”

Circulating Markers in Gastroenteropancreatic Neuroendocrine Tumors (GEP NETs)

“…Due to their rarity, they are difficult to diagnose and the begnning of the diagnostic process is often based on the measurement of circulating markers, before planning expensive and invasive diagnostic tests (2,3). A critical point is that the frequent late diagnosis of NETs is due to failure to identify symptoms or to establish the biochemical diagnosis; in fact 60-80% of NETs are metastatic at diagnosis.…”