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<.01). Patients with a measurable hormone response demonstrated an increased survival in comparison to those with no response (4.7 years vs 2.6 years, 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.