Management of metastatic phaeochromocytoma and paraganglioma: use of iodine-131-meta-iodobenzylguanidine therapy in a tertiary referral centre.

Background: Phaeochromocytoma (phaeo) and paraganglioma (PGL) are rare conditions, which are malignant in up to 30%. Optimal treatment is controversial, but in patients with metastatic iodine-131-meta-iodobenzylguanidine ((123)I-MIBG) avid tumours, we offer (131)I-MIBG therapy. We summarize response rates, survival and safety in a cohort of such patients treated with (131)I-MIBG in our centre from 1986 to 2012.

Design/methods: Retrospective analysis of the case notes of patients with metastatic phaeo/PGL who received (131)I-MIBG was undertaken; patients underwent clinical, biochemical and radiological evaluation within 6 months of each course of (131)I-MIBG therapy.

Results: Twenty-two patients (9 males) were identified, 12 with metastatic PGL and 10 with phaeo. Overall median follow-up time after first dose of (131)I-MIBG was 53 months. In total, 68 doses of (131)I-MIBG were administered; average dose was 9967 MBq (269.4 mCi). After the first dose, >50% of patients demonstrated disease stability or partial response; progressive disease was seen in 9%. A subset of patients underwent repeated treatment with the majority demonstrating partial response or stable disease. No life-threatening adverse events were reported, but three patients developed hypothyroidism and two developed ovarian failure after repeated dosing. Five-year survival after original diagnosis was 68% and median (+inter quartile range) survival from date of diagnosis was 17 years (7.6-26.4) with no difference in survival according to diagnosis (P < 0.1).

Conclusions: (131)I-MIBG is well tolerated and associates with disease stabilization or improvement in the majority of patients with metastatic phaeo/PGL. However, stronger conclusions on treatment effectiveness are limited by lack of a directly comparable 'control group' as well as an alternative 'gold standard' treatment.