Low-Dose Iodine-131 Metaiodobenzylguanidine Therapy for Patients With Malignant Pheochromocytoma and Paraganglioma

The following is a report on the clinical experience of an Israeli referral center for iodine-131 metaiodobenzylguanidine (131-MIBG) therapy for malignant pheochromocytoma (MPCC) and malignant paraganglioma (MPGG). The charts of 10 patients with MPCC (n = 7) and MPGG (n = 3) treated between 2000 and 2008 were reviewed. Response to 131-MIBG therapy was evaluated by tumor, hormone, and symptomatic relief criteria. The median follow-up was 18 months (2-48 months). The number of 131-MIBG treatments ranged from 1 to 4 (mean: 2.1). The average single dose of 131-MIBG was 5.4 +/- 0.2 GBq (145 +/- 5.0 mCi). The average cumulative dose was 11.6 +/- 1.6 GBq (310 +/- 44.0 mCi). There were no complete responses. Three patients (30%) had partial tumor response, 5 (50%) had stable disease, and 2 (20%) progressed after therapy. Five patients (50%) experienced symptomatic response. Hormone response was noted in 5 patients (50%). Progression-free survival was 17.5 months (2-47 months). One patient (10%) had thrombocytopenia and 2 patients (20%) developed subclinical hypothyroidism. Hormonal and symptomatic relief can be achieved with 131-MIBG therapy in patients with MPCC and MPGG with minor side effects.