[Radio iodized metaiodobenzylguanidine (MIBG) in the treatment of neuroblastoma: modalities and indications].

Neuroblastoma is the most common pediatric extracranial solid cancer. Patients with metastatic disease at initial diagnosis who are greater than 18  months of age and patients with MycN amplified locoregional tumors are treated with intensive multimodal therapy. While this intensive approach has been shown to improve outcome, patients with high-risk disease frequently relapse and fewer than 50% of these patients will be long-term survivors necessitating new approaches for therapy. Derived from the sympathetic nervous system, this tumor typically expresses the norepinephrine transporter. This transporter mediates active intracellular uptake of metaiodobenzylguanidine (MIBG) an analogue of norepinephrine in approximately 90% of patients allowing the use of radiolabeled (metaiodobenzylguanidine) MIBG, for targeted radiotherapy. This article will review the clinical experience of using MIBG as targeted radiotherapy in neuroblastoma. The administration guidelines, toxicity, response and survival are discussed. Recent studies have evaluated combinations of (131)I-MIBG with myeloablative regimens such as chemotherapy agents with radiation sensitizing properties, or with biologic agents. Most of them report a response rate of 30-40% with (131)I-MIBG in patients with relapsed or refractory neuroblastoma. Due to this high response rates and low non-hematologic toxicity, (131)I-MIBG seems to be an interesting agent for incorporation into the upfront management of newly diagnosed patients with high-risk neuroblastoma.