[Neuroendocrine tumors of the gastrointestinal tract].

Neuroendocrine tumors (NET) of the gastrointestinal tract are rare and constitute 0.5-1% of all human malignancies. Based on their endocrine secretion, they are functional active or inactive. They are further classified into fore-, mid-, or hindgut tumors. The recently published WHO-classification grouped the tumors according to their tumor size, angioinvasion and Ki-67 index. NET are mainly diagnosed in an advanced tumor stadium because of the paucity of symptoms or when symptoms occur due to endocrine hypersecretion. NET are diagnosed serologically by their hormone secretion and by measuring Chromogranin A levels. They are further detected by CT, MRI or endoscopy including endoscopic ultrasound. Many NET have somatostatin receptors on their surface and can be diagnosed by somatostatin receptor scintigrafy with high sensitivity and specificity. Only by surgery NET can be cured. Because many tumors are diagnosed late, medical options are of utmost importance. Symptom control can be established by somatostatin analogues and interferon-ot. Diazoxid can further inhibit insulin secretion, proton pump inhibitors are the therapy of choice for acid hypersecretion in Zollinger-Ellison syndrome. Advanced neuroendocrine cancers can be treated with chemotherapy. Recently, radio receptor therapy with 90Y-DOTA Octreotid and 177Lu-DOTA Octreotate was established in advanced neuroendocrine cancers and is further evaluated in studies. Net of the gastrointestinal tract should be treated in a multidisciplinary approach with gastroenterologists, surgeons and experts in nuclear medicine. An overview about epidemiology, clinical features, diagnostic methods and therapy of NET of the gastrointestinal tract will is provided in this article.