10-14 July 2000 Bristol Mariot Hotel, Bristol, UK Carcinoid tumours have an annual incidence of between 2 and 7 cases per million of population. The prevalence of these tumours may be in the region of 150 per million of population.
Many authors confuse incidence with prevalence.
There are many different classification systems used for carcinoid tumours, mostly put forward by histopathologists. The prognosis and activity of disease only correlates moderately with the classification, and it is particularly difficult to determine an individual prognosis for patients with endocrine tumours such as those given above. Ovarian carcinoids have also been described. Many patients have undiagnosed carcinoid tumours in the midgut that may secrete various hormones, that are only found incidentally at post mortem. Appendiceal carcinoids are an example of such.