SCINTISCANS AND CARCINOID-TUMORS

Background. The presence of somatostatin receptors on carcinoid tumors mediates imaging of tumor extent and inhibition of tumor growth and m arker secretion. This prospective study aimed to evaluate radiolabeled somatostatin analog scans in the therapeutic workup of carcinoids. Me thods. Twenty-one patients with carcinoids underwent 26 scans with iod ine octreotide or indium pentetreotide. The results for tumor and meta stases imaging were analyzed and compared with those of a short inhibi tion test of marker secretion and with those of metaiodobenzylguanidin e scan. Results. The sensitivity for obtaining images of the overall 4 3 tumor sites was 72%. We had no false-positive results. Unknown tumor sites were discovered in three patients. The results were slightly be tter with indium pentetreotide and metastases imaging. A positive scan did not always preclude responsiveness to the functional effect of oc treotide. Results of somatostatin analog scans were better than those with metaidobenzylguanidine. The two techniques were complementary in one patient. Conclusions. The choice of treatment for patients with ca rcinoid tumors should benefit from functional inhibition test with oct reotide and from indium pentetreotide and metaiodobenzylguanidine scan s