Meta[131I]iodobenzylguanidine therapy for patients with metastatic and unresectable pheochromocytoma and paraganglionna

Introduction: Pheochromocytomas (PHEOs)and paragangliomas (PGLs) are tumors that can exhibit a malignant behavior. Targeted radiotherapy with I-131-metaiodobenzylguanidine (I-131-MIBG) has proven useful in patients with unresectable, metastatic and/or relapsed disease. Methods: We review the literature and Our experience at UCSF to highlight important characteristics of PHEO/PGL and the use of 131 I-MIBG in the treatment of this disease. Results: These turners are rare, with a diagnosed incidence of only two to four cases per million annually, 40% are discovered at autopsy. Clinical manifestations are caused by excess secretion of catecholamines, although Sonic PGLs are nonsecretory. Approximately 25% of patients with PHEO/PGLs have an underlying genetic predisposition. The risk of a germline mutation is higher in children. Diagnostic evaluation should include serial determinations of fractionated metanephrine and serum chromogranin A. Staging requires both I-121-MIBG and full-body magnetic resonance imaging or (18)FDG-PET scanning. The primary treatment for PHFO/PGL is resection. Patients may be candidates for treatment with I-131-MIBG if they have unresectable or metastatic tumors that are avid for MIBG. Such patients usually respond to this targeted radioisotope therapy and many achieve a durable remission. Myelosuppression is a close-related side effect that call be treated with transfusions or autologous hematopoietic stern cells. Late side effects can include infertility, rnyelodysplasia and second cancers. Conclusions: Treatment with I-131-MIBG call be considered for patients if Surgery is not feasible. There are significant risks associated with this treatment, but the Majority of patients will respond. Treatment with I-131-MIBG should be done at institutions With experience ill delivering targeted radiotherapeutics. (C) 2008 Elsevier Inc. All rights reserved.