Application of peptide/cell receptor kinetics utilizing radiolabelled somatostatin congeners in the IN SITU, IN VIVO detection and differentiation of neoplastic tissue

摘要

Broadly, the present invention is directed to a method for the detection and differentiation of neoplastic tissue in a patient suspected of having neoplastic tissue. The method includes the administration of a radiolabeled somatostatin congener to the patient and accessing the patient with a radiation detection probe for determining tissue exhibiting elevated levels of radiation, viz., neoplastic tissue. However, before subjecting the patient to such administration, an initial determination preferably is made as to whether the radiolabeled somatostatin congener will bind to the tumor site, i.e., whether somatostatin receptors are associated with the neoplastic tissue. This is conveniently done with a wide variety of endocrine tumors, which release peptides or hormones, referred to as "biochemical markers." In order to make this determination, initially a biochemical marker-inhibiting dose of unlabeled somatostatin congener is administered to the patient. The biochemical marker associated with the neoplastic tissue then is monitored to determine whether the administered somatostatin congener reduces the presence of the marker in the patient. If the monitored presence of the marker was reduced, then the surgeon can be confident that the neoplastic tissue or tumor contains receptors to which the somatostatin will bind. Thus, the administration of radiolabeled somatostatin congener is appropriate for such patient. If the biochemical marker associated with the neoplastic tissue is not appropriately reduced following the administration of the unlabeled somatostatin congener, then the neoplastic tissue may not be determinable by the use of radiolabeled somatostatin congener and alternative modalities of treatment should be considered, such as the use of radiolabeled antibodies as proposed in U.S. Patent No. 4,782,840. If the tumor is of a type that does not release a biochemical marker, the presence of somatostatin receptors can be confirmed by other means, such as pathology, immunohistochemistry, radioreceptor assay, or such other means as will be apparent to those skilled in the art.