[Gastroenteropancreatic neuroendocrine tumours (carcinoid tumours): definition, clinical aspects, diagnosis and therapy].

Carcinoid tumours are rare neuroendocrine tumours. In 2000 the WHO developed a new classification which gives a better description of the characteristics and biological behaviour of the tumour. Their advised designation is gastroenteropancreatic neuroendocrine tumour (GEP-NET). Somatostatin receptor scintigraphy has the highest sensitivity for visualisation of GEP-NETs. In the recent past years new positron emission tomography (PET) tracers have been developed and PET scanning is likely to become an important tool in the near future. Surgical resection is the treatment of first choice for a patient with a GEP-NET. In metastatic disease a number of forms ofpalliative treatment are possible. Cytotoxic chemotherapy seems only to be effective in aggressive, poorly-differentiated tumours. Therapy with somatostatin analogues leads to objective tumour regression in a minority of patients only. New advances in peptide receptor radionuclide therapy using radioactive-labelled somatostatin analoga are showing better results.