Radioiodine-Labeled Meta-Iodobenzylguanidine for Imaging and Treatment of Pheochromocytoma/Paraganglioma and Neuroblastoma

Abstract

Following the new WHO classification of tumors of the endocrine organs (Lloyd RV, Osamura RY, Klöppel G, Rodai J, editors. WHO classification of tumours of endocrine organs. Lyon: International Agency for Research on Cancer; 2017), this chapter deals with the development of radionuclide therapy of malignant pheochromocytomas, parangliomas, and neuroblastomas. All of these tumors are expressing the noradrenaline transporter, which is responsible for the active uptake of 131I-meta-iodobenzyguanidine (131I-mIBG) into the tumor cells. This tracer was introduced for diagnostic procedures of the adrenal medulla, for the treatment of adrenal medullary hyperplasia and also for malignant neuroendocrine tumors in 1980/1981, and these treatment indications are still valid until today. For treatment of malignant pheochromocytomas and paragangliomas, an improvement of 5-year overall survival in about 36% was published.In Germany, the most common indication for 131I-mIBG therapy in high-risk neuroblastoma patients is the treatment of persistent mIBG-avid disease before autologous stem cell transplantation. However, 131I-mIBG may also be used in case of neuroblastoma relapse or in palliative intent, in other countries also as first-line treatment. Mean objective tumor response for 131I-mIBG in neuroblastoma was reported with about 32%.Some promising results of recent studies using new tracers (DOTATOC, DOTATATE) with newer beta-emitters are also discussed.