Neuroendocrine gastroenteropancreatic
tumors are rather rare
neoplasms with an incidence of 1-2 cases per 100,000 people. They show rather varying
tumor biology and present sometimes distinct clinical symptoms such as
flushing, diarrhoea,
hypoglycemia and
gastric ulcers. The biochemical diagnosis is today significantly improved by the introduction of
chromogranin A as a general
tumor marker, which is also useful in histopathology. Today the localization procedures include
somatostatin receptor scintigraphy as the primary investigation together with CT or ultrasonography. The basis for treatment of neuroendocrine GEP
tumors is not only a curative intent but merely amelioration of clinical symptoms, abrogation of
tumor growth, maintaining and improvement of quality of life. Surgery has always to be considered in the treatment of neuroendocrine GEP
tumors. It can be performed whenever during the course of the disease but it may be more productive in earlier stages. Liver dearterialization procedures can furthermore reduce the
tumor masses in liver together with
laser treatment or
radiofrequency therapy. The medical treatment includes
cytotoxic agents, alpha
interferons and
somatostatin analogues.
Somatostatin analogues will always be combined with the other two alternatives to reduce clinical symptoms.
Chemotherapy is particularly useful for patients with more aggressive
tumors with high proliferation capacity, whereas
alpha interferon is beneficial in classical midgut
carcinoids with low proliferation capacity. Quite recently
somatostatin based radioactive
tumor targeted treatment has evolved with preliminary promising data but further studies are needed to deliniate its future role in the treatment of
neuroendocrine tumors in patients.