(131)I-MIBG therapy for malignant paraganglioma and phaeochromocytoma: systematic review and meta-analysis

(131)I-MIBG therapy can be used for palliative treatment of malignant paraganglioma and phaeochromocytoma. The main objective of this study was to perform a systematic review and meta-analysis assessing the effect of (131)I-MIBG therapy on tumour volume in patients with malignant paraganglioma/phaeochromocytoma.

A literature search was performed in December 2012 to identify potentially relevant studies. Main outcomes were the pooled proportions of complete response, partial response and stable disease after radionuclide therapy. A meta-analysis was performed with an exact likelihood approach using a logistic regression with a random effect at the study level. Pooled proportions with 95% confidence intervals (CI) were reported.

Seventeen studies concerning a total of 243 patients with malignant paraganglioma/phaeochromocytoma were treated with (131)I-MIBG therapy. The mean follow-up ranged from 24 to 62 months. A meta-analysis of the effect of (131)I-MIBG therapy on tumour volume showed pooled proportions of complete response, partial response and stable disease of, respectively, 0·03 (95% CI: 0·06-0·15), 0·27 (95% CI: 0·19-0·37) and 0·52 (95% CI: 0·41-0·62) and for hormonal response 0·11 (95% CI: 0·05-0·22), 0·40 (95% CI: 0·28-0·53) and 0·21 (95% CI: 0·10-0·40), respectively. Separate analyses resulted in better results in hormonal response for patients with paraganglioma than for patients with phaeochromocytoma.

Data on the effects of (131)I-MIBG therapy on malignant paraganglioma/phaeochromocytoma suggest that stable disease concerning tumour volume and a partial hormonal response can be achieved in over 50% and 40% of patients, respectively, treated with (131)I-MIBG therapy. It cannot be ruled out that stable disease reflects not only the effect of MIBG therapy, but also (partly) the natural course of the disease.