Iodine -131 metaiodobenzylguanidine is an effective treatment for malignant pheochromocytoma and paraganglioma☆

Abstract Introduction Iodine 131–meta-iodobenzylguanidine ( 131 I-MIBG) has been applied to the palliative treatment of metastatic pheochromocytoma in small studies. We report our institutional experience for the treatment of metastatic pheochromocytoma and paraganglioma. Methods We performed a retrospective review of 33 patients with metastatic pheochromocytoma (n = 22) and paraganglioma (n = 11) treated at our institution with 131 I-MIBG over a 10-year period. Results Patients received a mean dose of 388±131 mCi 131 I-MIBG. Median survival after treatment was 4.7 years. Most patients experienced a symptomatic response leading to an improved survival (4.7 years vs 1.8 years, P P  = .01). Patients who received a high dose (>500 mCi) as their initial therapy also had improved survival (3.8 years vs 2.8 years, P  = .02). Conclusion These data support 131 I-MIBG treatment for select patients with metastatic pheochromocytoma. In our experience, prolonged survival was best predicted by symptomatic and hormone response to 131 I-MIBG treatment. An initial dose of 500 mCi may be optimal. The benefit of 131 I-MIBG treatment for metastatic pheochromocytoma must also be weighed against its side effects.