27 children with neuroblastoma were treated with 131I-Metaiodobenzylguanidine (MBIG). They were either refractory to conventional therapy or experienced relapse after initially successful treatment. 7 children revealed stage IV and 20 stage III at the beginning of MIBG-treatment. MIBG was administered by infusion lasting from 30 min to 30 hrs. In most children the dose was split into two portions each infused over a period of 4 hrs with a 24 hrs interval between. Courses were repeated up to 6 times and maximum activity given to one patient cumulatively was 38,221 MBq. 24 patients were evaluable for analysis of results. In 4 children (16.7%) a CR was observed, in 10 (41.7%) a PR, in 5 (20.8%) a disease stabilization and 5 were nonresponders. The 4 CR-patients were initially stage IV. 3 of them were treated in addition by bone marrow transplantation (bmt), one by further chemotherapy. 3 died of a relapse, 1 of complications from bmt. 5 of the 10 PR-patients died of tumor progression, 3 achieved a CR by additional chemotherapy, 1 a PR by bmt and 1 stays in PR without further measures. 2 of the 5 children with a disease stabilization were the first treated patients to whom a fairly low dose was given. In 3 of the 5 nonresponders no uptake of MIBG was observed; they died from tumor progression. 1 of the 2 nonresponders with uptake died of graft-versus-host disease after bmt, 1 other also of tumor progression. Duration of remission was between 1 and 12 months and depended upon uptake and dose of MIBG, interval between administrations and individual tumor behaviour. Side effects were seen as marked bone marrow depression; this was reversible in any case and we did not loose a patient due to MIBG-induced leuko- or thrombopenia. In cases of severely ill children we observed a very fast and dramatical amelioration in clinical conditions. With this method even in neuroblastoma relapse and in nonresponders complete remissions are achievable. Important is the intensification of the therapeutical effect by additional chemotherapy or in combination with bmt. For a definitive evaluation further investigations are necessary to optimize therapeutic strategies.
3-Iodobenzylguanidine Adolescent