Diagnosis and treatment of Liver metastases from neuroendocrine tumors

Neuroendocrine tumors are rare and slowly progressing malignancies developing predominantly in the gastrointestinal tract. Often symptoms caused by excessive hormone production lead to diagnosis, especially when active metabolites are released from hepatic metastases to reach the systemic circulation before they are inactivated in the liver. Preoperative diagnosis of specific tumors relies on demonstration of the respective hormones in serum or urine rather than on histological diagnosis. Localization of primaries or their metastases can be accomplished by CT-AP, somatostatin receptor scintigraphy, SPECT or PET studies with high sensitivity. At the time of diagnosis more than 60% of tumors have already spread to the liver. Potentially curative resection of liver metastases can achieve 5-year survival rates of more than 60%. Since excess hormone production may be incapacitating and even life-threatening, effective palliation is highly important. Five-year survival following palliative liver resection was calculated to be almost 40%. Palliative liver resection may therefore be considered an alternative to liver transplantation with 5-year survival of 34% in a collected series. If liver resection is not possible, al least temporary palliation of symptoms and retardation of tumor growth can effectively be achieved with somatostatin analogues.