ABSTRACT Introduction: Neuroblastoma, a neoplasm of the sympathetic nervous system, is the second most extra- cranial malignant solid tumor of childhood. Many thera- peutic 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 high- risk neuroblastoma. Radio-labeled MIBG therapy has been tried in the treatment of advanced stage 3&4 neuro- blastoma 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 the 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 Journal of the Egyptian Nat. Cancer Inst., Vol. 21, No. 1, March: 51-58, 2009 Role of 131-I MIBG Therapy in the Treatment of Advanced Neuroblastoma RAEF RIAD, M.D.*; MAGDY KOTB, M.D.*; WALID OMAR, M.D.*; AHMED ZAHER, M.D.*; KHALED KHALAFALLA, M.D.*; MOHAMED FAWZY, M.D.**; MOHAMED EL-WAKIL, M.D.*** and EMAD EBEID, M.D.** The Departments of Nuclear Medicine*, Pediatric Oncology**, National Cancer Institute, Cairo University and Clinical Oncology***, Faculty of Medicine, Beni-Suef University. 51 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%. Conclusion: We concluded that 131-I MIBG therapy has favorable therapeutic effect for advanced neuroblas- toma patients. Controlled clinical trials should be consid- ered to evaluate the true potential of 131-I MIBG therapy. Key Words: MIBG therapy – Advanced neuroblastoma. INTRODUCTION Neuroblastoma is the most common solid extra cranial malignancy in children younger than 15 years. It accounts for 8-10% of all childhood cancers and 15% of cancer deaths in children [1]. Although this tumor is chemo- and radio-sensitive, it is prone to relapse after initial induction of remission. Stage 1 and 2 tumors can be cured with surgery alone, whilst stage 3 tumors require preoperative chemotherapy. Sixty percent of neuroblastomas in children are diag- nosed in stage 4, of whom many have biological markers of poor prognosis, such as MYCN amplification or 1p deletion [2] . One of the major goals of cancer treatment is to develop therapies affecting cancer cells while causing little or no damage to the normal counterparts. In this perspective, numerous attempts have been made to bind anti-tumor compounds or radioactive isotopes to molecules specifically taken up by tumor cells. One example of these molecules is meta-iodobenzylguanidine (MIBG), a norepinephrine analogue which is taken up by organs rich in adrenergic innervation and/or Correspondence: Dr. Emad Ebeid, Prof. of Pediatric Oncology NCI Cairo University, Cairo Egypt, emadebeid@hotmail.com