Recent developments in diagnosis and treatment of metastatic carcinoid tumours

In carcinoid patients a tumour of enterochromaffin cell origin is present, which dependent on the site of origin can result in increased serotonin production. Metastasized carcinoids are often diagnosed by measuring 5-hydroxyindoleacetic acid excretion in the urine. This excretion, however, can be influenced by food intake. On the other hand, serotonin measured in blood platelets is unaffected by food intake and, in addition, is found to be more sensitive. Therapy of metastasized carcinoids is directed at tumour reduction or only reduction of symptoms. Tumour reduction can be achieved surgically or by embolization. Combination chemotherapy has a maximum response percentage of about 33%. Over the last few years, both octreotide and interferon alpha have been used in these patients. They rarely result in a reduction of the tumour size (10-20%). Symptom reduction is achievable in most patients with these agents, however. Recently, increasing knowledge obtained concerning the various serotonin receptors and their antagonists is now being used in the treatment of patients with a metastasized carcinoid. In the future it is expected that the different modalities will be combined increasingly.