The diagnosis and medical management of gastroenteropancreatic neuroendocrine tumors (GEP NET)

Gastroenteropancreatic neuroendocrine tumors (GEP NET) constitute a heterogeneous group of neoplasms that are often associated with typical symptoms due to excessive and uncontrolled production of hormones and bioactive substances. The choice of treatment for GEP NET depends primarily on the pathologic differentiation and stage at diagnosis but also on the presence of symptoms related to hormonal secretion. Assessment of specific or nonspecific tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include computed tomography and magnetic resonance imaging, scintigraphy with somatostatin analogs, endoscopic ultrasonography, endoscopy and substraction angiography. Surgery remains the first line therapy in NET. However these tumors are usually diagnosed at an advanced stage when cure cannot be achieved. Somatostatin analogs are important agents in the medical treatment of GEP NET. In selected cases of advanced, non-resectable disease, interferon alpha, radionuclides, ablation therapies and chemotherapy can be performed.