COMPARISON OF SOMATOSTATIN ANALOG AND METAIODOBENZYLGUANIDINE SCINTIGRAPHY FOR THE DETECTION OF CARCINOID-TUMORS

The purpose of this prospective study was to compare the ability of ra diolabelled somatostatin analogue (RSA) and metaiodobenzylguanidine (M IBG) scintigraphy to display carcinoid tumours. Forty patients were st udied after radiological assessment based on clinical symptomatology. These patients had radiologically demonstrated rumours (n=28), resecte d tumours discovered to be of the. carcinoid type (n=5) or clinically and biologically suspected carcinoid tumours (n=7), They underwent ind ium-111 DTPA-pentetreotide or iodine-123-Tyr-3-octreotide and I-131-MI BG scintigraphy. The results were compared with those of complementary surgical or morphological examinations and analysed according to the site of the tumour and the symptomatology. In the case of 31 patients with a total of 55 tumoral sites: the sensitivity of the initial radio logical assessment, of RSA and of MIBG was 96%, 86% and 64%, respectiv ely, for the detection of at least one tumour per patient but 51%, 85% and 51%, respectively, for the total number of sites, No site was det ected solely by MIBG. The concordance between RSA and MIBG nias better when all sites were considered (kappa index+0.44) than for only extra hepatic abdominal tumoral sites (kappa index+0.095). Abdominal, thorac ic or bone marrow rumours were more easily detected with RSA than with MIBG. Hepatic invasion (21 cases) was more easily detected by radiolo gy (sensitivity 100%) than by RSA and MIBG, both of which displayed a sensitivity of 80%, but with differences in uptake intensity. Tumour d etection using MIBG was more significantly linked with flush (P<0.01) than with diarrhoea (P>0.10). In the assessment of carcinoid tumours, RSA scintigraphy should be carried out initially (just after hepatic u ltrasonography) and supplemented by MIBG, as comparison of the studies serves to guide therapeutic options and might be valuable for prognos is.