131I-MIBG Therapy in metastatic phaeochromocytoma and paraganglioma

Purpose (131)Iodine metaiodobenzylguanidine (I-131-MIBG) is a radiopharmaceutical used for scintigraphic localisation of phaeochromocytomas and paragangliomas. The experience with its therapeutic use is limited. We report our experience for the treatment of malignant phaeochromocytoma and paraganglioma. Materials and methods The charts of 19 patients with malignant phaeochromocytoma (n=12) or paraganglioma (n=7), who were treated with I-131-MIBG, were retrospectively reviewed. Four patients (21%) received radiotherapy, three (16%) chemotherapy, and in one patient (5%), both chemotherapy and radiotherapy was given before I-131-MIBG therapy. Response to I-131-MIBG treatment was evaluated by objective as tumour response, biochemical and subjective response. Results Of the 19 patients, 13 (68%) were men, 6 (32%) were women. Ages ranged from 22 to 68 years (median, 47). The median initial dose was 7.4 GBq (200 mCi; range, 6.7 GBq-25.9 GBq, 180-700 mCi); median cumulative dose was 22.2 GBq (600 mCi; range, 6.8 GBq-81.4 GBq, 183-2200 mCi). Objective tumour response was achieved in 47% of the patients. Biochemical response rate was 67%, and symptomatic response was seen in 89% of the patients. Overall median follow-up was 29 months, with a range of 3-93 months. Haematologic complications were the most common side effects and were observed in 26% of the patients. Conclusion Our data support that symptomatic and biochemical response can be reached with I-131-MIBG therapy in patients with metastatic phaeochromocytoma and paraganglioma. Although complete tumour response was not observed, the palliation and control of tumour function by I-131-MIBG therapy may be valuable for the patients.