Somatostatin Receptors in the Diagnosis and Therapy of Neuroendocrine Tumors

Abstract

The expression of somatostatin receptors in neuroendocrine tumors has facilitated the diagnosis and surgical treatment of patients with these tumors. After injection of a radiolabeled long-acting somatostatin analog, 111In-octreotide, scintigraphic tumor imaging can be performed as well as intraoperative tumor localization. During localization studies very high 111In concentration values were found in tumor tissues versus normal tissues, especially in carcinoid tumors and endocrine pancreatic tumors. Studies on such tumors in cell culture further indicated internalization of 111In into tumor cells, which is a prerequisite for a radiobiological effect from short range Auger and conversion electrons. Attempts to systemic radionuclide therapy via somatostatin receptors in patients with neuroendocrine tumors have been initiated.