THE DIAGNOSTIC AND THERAPEUTIC UTILITY OF RADIOIODINATED METAIODOBENZYLGUANIDINE (MIBG) - 5 YEARS OF EXPERIENCE

The authors' experience of more than 5 years in the diagnostic and therapeutic use of radioiodinated MIBG in neural crest tumors is reported.123I/131I-MIBG scintigraphhy was performed in 158 patients: 75 suspected (24 proven) pheochromocytomas (pheos), 43 neuroblastomas (NB), 20 medullary thyroid carcinomas (MTC), 6 ganglioneuromas, 5 carcinoids and 1 insulinoma. Eight cases of tumors not originating from the neural crest were also investigated. The diagnostic sensitivity of the method was above 90% both in pheos and NB (primary tumors and bone metastases). The examination was less effective in localizing MTC (sensitivity=64.4% in primary or residual/recurrent tumors). The scintigraphie outcome was negative in ganglioneuromas, carcinoids and insulinoma. Specificity was very high (> 95%), and no false positive results were found in tumors not deriving from the neural crest. 131I-MIBG treatment was administered to four patients with malignant pheo, nine with NB and four with MTC. Therapy resulted in a complete response in one pheo, two NB and one MTC treated after surgery or at diagnosis (one NB), it gave partial response and prolonged remission in five advanced cases (one pheo, two NB and two MTC); it resulted in temporary stabilization of the disease in one pheo and two NBs, it was ineffective in four cases. © 1990 Springer-Verlag.