Recombinant human thyrotropin before radioiodine therapy was associated with a 35% greater reduction in volume of nontoxic nodular goiters than that achieved with radioiodine alone, but with a fivefold increase in the rate of hypothyroidism, Danish researchers reported in the first large, double-blind, randomized, controlled trial of this therapy for nontoxic nodular goiter.
Dr. Viveque E. Nielsen of Odense (Denmark) University Hospital and colleagues assessed the effect of recombinant human thyrotropin (rhTSH) administered prior to treatment with radioiodine (iodine-131) in patients with nontoxic nodular goiter who were seen at the investigators' outpatient clinic (Arch. Intern. Med. 2006;166:1476–82).
Patients received 0.3 mg of either rhTSH or a placebo saline injection 24 hours before treatment with radioiodine doses customized to each patient, based in part on radioiodine uptake measured at baseline and 12 months. End points of thyroid size and function were assessed at 3, 6, 9, and 12 months, as were patient satisfaction before therapy and at 3 months and 1 year post treatment, via a visual analog scale.
In all, 57 patients were included in the final study results. In the placebo group, the median goiter volume had dropped from the baseline measure of 51 mL to 27 mL. The rhTSH group saw a decline from a median of 59 mL at baseline to a median of 20 mL at 12 months. Moreover, mean reduction at 12 months was 46% for the group receiving radioiodine alone and 62% for the group treated first with rhTSH—a difference of 16 percentage points, which constitutes a 35% advantage over the reduction achieved solely with radioiodine.
However, in terms of thyroid function, hypothyroidism developed in 62% of the rhTSH group versus 11% of the placebo group. And adverse events were more common in the rhTSH group—namely, hypothyroid symptoms, nausea, and headache.