Carcinoid tumours.
Carcinoid tumours offer a diagnostic and therapeutic challenge. Although new biochemical markers and improved methods for tumour detection, including PET and somatostatin receptor scintigraphy, have been developed during the last two decades many patients are still diagnosed at late stages of the disease. This is supported by the fact that the age of diagnosis is about the same today as it was 10 years ago. It is our opinion that plasma chromogranin A levels should be be determined in all patients which are investigated because of symptoms that might be connected to a neuroendocrine tumour. In cases with flushing or diarrhoea, U-5-HIAA should also be determined and these two tumour markers are enough to diagnose most patients with midgut carcinoid tumours. In patients with foregut or hindgut tumours other specific hormones should be included. For the localization procedure conventional radiological techniques including CT, MRI and ultrasound investigations should be supplemented with somatostatin receptor scintigraphy. Endoscopic ultrasound investigations might in the future be relevant for diagnosis of duodenal carcinoids, whereas gastric and rectal carcinoids are diagnosed by endoscopy. A combination of more aggressive surgery combined with medical treatment such as somatostatin analogues and alpha-interferon has significantly increased the survival rates in patients with classical midgut carcinoid tumours. Metastatic foregut and hindgut tumours are still a therapeutic challenge and it is important in the future to classify all carcinoid tumours based on specific tumour biology patterns. Such a tumour biology based treatment is a prerequisite for a more individually based therapy in the future.