Background. Despite of improving diagnostics, development of new drugs and treatmen strategies, pa tients with biologically unfavourable, advanced or relapsed neuroblastoma remain practically incurable. Treatment related toxicity, requirement for personnel and financial costs have became limiting. Tumor specific therapy represented by 131 I-meta-iodobenzylguanidine (MIBG) administration could become an alternative improving the overall survival. In comparison with standard external radiotherapy the targeted therapy enables to achieve radiation 5 to 10 times higher with lower organ toxicity. Data published by European and American colleagues brought evidence of high efficacy of this method. It motivated us to set and develop the method at our department. Type of Study. Retrospective analysis of therapeutic results and side effects of the administration of 131 I-meta- -iodobenzylguanidine in high-risk neuroblastoma patients cured at the Department of Pediatric Oncology in Prague since 1997 till 2000. Method and Results. 131 I-meta-iodobenzylguanidine was fourteen times therapeutically administered in seven high-risk relapsed neuroblastoma patients. Four children received a single dose of 131 I-meta-iodobenzylguanidine, three patients were treated repeatedly. The first dose represented 5,5 GBq, repeated dose 3,7 GBq, irrespective to the body weight. Each MIBG administration was followed by four days hyperbaric oxygen therapy. The treatment was well tolerated, acute and late side effects were not serious and only rarely reached grade 3 or 4 according to the International North American Children’s Cancer Group Classification. Three of the seven children have survived with no evidence of the disease. Four children died of the disease progress. Conclusions. 131 I-meta-iodobenzylguanidine treatment combined with hyperbaric oxygen therapy becomes a well- tolerated therapy for high-risk neuroblastoma patients non-responding to the conventional treatment. Though the 131 I-meta-iodobenzylguanidine administration probably cannot cure these patients, the repeated administration can bring long lasting remission.

        Key words: neuroblastoma, I MIBG, targeted radiotherapy, hyperbaric oxygen therapy, therapy.