High‐dose 131I‐metaiodobenzylguanidine therapy for 12 patients with malignant pheochromocytoma

Abstract

BACKGROUND ¹³¹I‐Metaiodobenzylguanidine (¹³¹I‐MIBG) can be used systemically to treat malignant pheochromocytoma. To improve outcome, the authors used higher levels of activity of ¹³¹I‐MIBG than previously reported. The authors reported the response rates and toxicity levels in patients with malignant pheochromocytoma or paraganglioma who were treated with high‐dose ¹³¹I‐MIBG. METHODS Following debulking surgery and stem cell harvest, 12 patients with malignant pheochromocytoma or paraganglioma were treated with ¹³¹I‐MIBG. Five had received previous external beam radiation and/or chemotherapy. The median single treatment dose was 800 mCi (37 gigabecquerels; range, 386–866 mCi) or 11.5 mCi/kg (range, 5.6–18.3 mCi/kg). The median cumulative dose was 1015 mCi (range, 386–1690 mCi). RESULTS Three patients had a complete response, two of whom had soft tissue and skeletal metastases. Their median follow‐up was 45 months (range, 23–101 months). Seven patients had a partial response (PR), with a median follow‐up 43 months (range, 6–47 months). Two patients without a response died with progressive disease (PD) and 2 patients with an initial PR died of PD at 13 and 11 months, respectively. Grade 3 thrombocytopenia occurred after 79% (15 of 19) of treatments had been administered. Grade 3 and 4 neutropenia followed 53% (10 of 19) and 19% (4 of 19) of treatments, respectively. One patient required stem cell infusion, and one developed primary ovarian failure. CONCLUSIONS The single and cumulative doses of ¹³¹I‐MIBG were approximately 2–3.5 times higher than those used at other centers. Unlike previous reports, two patients with both skeletal and soft tissue metastases had a complete response. Hematologic toxicity was significant but tolerable. High‐dose ¹³¹I‐MIBG may lead to long‐term survival in patients with malignant pheochromocytoma. Cancer 2003;98:239–48. © 2003 American Cancer Society. DOI 10.1002/cncr.11518