Hypertension complicating 131I-meta-iodobenzylguanidine therapy for neuroblastoma

Radiolabelled meta-iodobenzylguanidine (mIBG), used as targeted therapy for neuroblastoma, is known to have effects on blood pressure (BP). In this study we audited BP changes in patients receiving (131)I-mIBG therapy for neuroblastoma to identify BP-related adverse events (AE) and possible predictive factors.

Between 2003 and 2010, 50 patients with neuroblastoma received 110 (131)I-mIBG administrations. BP measurements before and after administration were compared with age- and sex-matched centile values. AE were analysed, and possible predisposing factors identified.

This population had a baseline BP distribution higher than that of their age- and sex-matched peers, with 16% of preadministration systolic BP values above the 95th centile. Changes in BP after administration showed an approximately normal distribution with similar numbers of reduced and increased values. Four AE, all related to hypertension, occurred with one patient having generalized seizures. One AE was immediate, others occurred between 20 and 25 h after administration. No significant association between AE and patient age or sex was demonstrated. However, a significant association between AE and high preadministration BP was shown, both above the 90th centile (p = 0.0022) and above the 95th centile (p = 0.0135).

Clinically relevant hypertension following (131)I-mIBG therapy affected less than 5% of administrations, but was more common in those patients with preexisting hypertension. As hypertensive episodes may occur many hours after treatment, close monitoring of BP needs to be continued for at least 48 h after administration of (131)I-mIBG.