Epidemiology of neuroendocrine tumours.

Neuroendocrine tumours account for only 0.5% of all malignancies. The incidence is approximately 2/100,000 with a female preponderance under the age of 50 years due to appendiceal location. The main primary sites are the gastrointestinal tract (62-67%) and the lung (22-27%). Presentation with metastatic disease accounts for 12-22%. In the last decades, the incidence has been rising. This might be due to more awareness, improved diagnostic tools or a change in definition. Most neuroendocrine tumours are mainly sporadic, but association with the multiple endocrine neoplasia type 1 syndrome and clustering within families is known. Also an increased risk of secondary cancers has been reported, but numbers are small. The 5-year survival is mainly associated with stage: 93% in local disease, 74% in regional disease and 19% in metastatic disease. In metastatic disease, survival increased since 1992, when treatment with octreotide became largely available in The Netherlands.