Neuroendocrine tumors (NETs) are a heterogeneous group of tumors originating in various anatomic locations, comprising nearly
0.49% of all malignancies. In 2003, Modlin et al. analyzed 13715 NETs, gastrointestinal tract showed the highest incidence (67.5%)
followed by the bronchopulmonary NETs (25.3%). And among gastrointestinal NETs, most of them occurred in the small intestine
(41.8%), followed by the rectum (27.4%) and stomach (8.7%). Maggard et al. including 11427 NETs reported a 5-year survival rate of 87.5%
for rectal NETs, and in colorectal NETs without metastasis showed a 5-year survival of 85-99% and the rates of 54-73% and 15-30% for
regional and distant metastasis, respectively. The term NETs of gastroentero-pancreatic (GEP) tract was defined as ââ¬Åcarcinoidââ¬Â one century
ago and actually known as NET. GEP-NETs have been reported to present increased incidence. NETs arise from the neuroendocrine cell. In GI tract and pancreas,
there are 14 different cells defined by hormonal reagents, many of NETs manifest hormonal syndromes. GEP-NETs associated with
hormonal syndromes are called insulinomas, glucagonomas and gastrinomas. In addition, some can produce hormones which are
ectopic to the GEP system such as vasoactive intestinal polypeptide (VIP), ACTH or GH-releasing factor.
Last date updated on September, 2024