Role of 131-I MIBG Therapy in the Treatment of Advanced Neuroblastoma.

Introduction: Neuroblastoma, a neoplasm of the sympathetic nervous system, is the second most extracranial malignant solid tumor of childhood. Many therapeutic strategies has evolved over the last 20 years, based upon work by international cooperative groups and smaller cohort studies. Novel therapies to improve initial disease response and treatment of minimal residual disease are required to improve survival for these children with highrisk neuroblastoma. Radio-labeled MIBG therapy has been tried in the treatment of advanced stage 3&4 neuroblastoma in an attempt to improve patients' outcome. The use of radio-labeled MIBG to treat neuroblastoma has arisen from the high sensitivity and specificity of in-vivo MIBG imaging for detection of primary and metastatic tumors.

Aim Of Work: To determine the impact of MIBG therapy on neuroblastoma patients' outcome and its impact on their quality of life.

Patients And Methods: Thirty pediatric patients with stage 4 pathologically proven neuroblastoma are included in this study. Eighteen of the study patients (60%) were males and 12 (40%) were females. All the patients had partially responsive tumor to first-line therapy +/- surgey. 131-I MIBG doses ranged from 100 to 150mCi with number of courses ranged from 1-7 according to response and toxicity.

Results: Two patients achieved complete remission (CR) and were still disease-free after 64 &69 months. Nine patients showed partial remission (PR) to 131-I MIBG, all the nine patients were alive at 16-57 months (mean 30.6 months) among whom seven were alive with stable disease and two patients were alive with progressive disease (PD) at the end of study. Eighteen patients remained stable after 131-I MIBG therapy, among them six were alive with PD and four were alive with stable disease at the end of study, while the remaining eight patients died. The last patient developed PD and died within 15 months. The 5 years event free survival (EFS) was 48.2% and the overall survival (OS) was 69%.

Conclusions: We concluded that 131-I MIBG therapy has favorable therapeutic effect for advanced neuroblastoma patients. Controlled clinical trials should be considered to evaluate the true potential of 131-I MIBG therapy.

Key Words: MIBG therapy - Advanced neuroblastoma.