E-news: rhTSH allows effective goitre reduction with lower iodine doses

Fast et al report new evidence that pre-treatment with recombinant human TSH augments the reduction of goitre volume over and above the observed augmentation in the uptake of radioactive iodine.

Observations indicate that stimulation with recombinant human TSH (rhTSH) before radioiodine (131I) therapy augments goitre volume reduction (GVR). In this double-blinded study of 90 patients with a nontoxic nodular goitre, patients were randomised to either 0.1 mg rhTSH (n=60) followed by a thyroid dose of 50 Gy or placebo followed by 100 Gy (n=30).

At 12 months, the mean relative GVR in the placebo and the rhTSH group was identical (35 ± 3%; P=0.81) and goitre-related symptoms were effectively relieved in the majority of patients in both groups. There was no difference in the incidence of hypothyroidism post radioactive iodine.

However, the median administered 131I-activity, was 170 MBq (45-1269) in the rhTSH group and 559 MBq (245-3530) in the placebo group (70% reduction, P < 0.0001). This study therefore demonstrates that rhTSH not only increases 131I uptake, but also potentiates the effect of 131I-therapy, allowing a major reduction of the 131I-activity without compromising efficacy. This approach is attractive in terms of minimizing post therapeutic restrictions and in reducing the potential risk of radiation-induced malignancy.