Stimulation with 0.3-mg recombinant human thyrotropin prior to iodine 131 therapy to improve the size reduction of benign nontoxic nodular goiter -: A prospective randomized double-blind trial

Background: Use of recombinant human thyrotropin increases the thyroid radioiodine (iodine 131 [I-131]) uptake and may have a role in the context of I-131 therapy of benign goiter. Methods: In a double-blind, placebo-controlled trial, 57 patients with nodular nontoxic goiter (51 women and 6 men) were randomized to receive either 0.3 mg of recombinant human thyrotropin (n= 28) or placebo (n= 29) 24 hours before I-131 therapy. The I-131 dose was calculated based on thyroid size (measured by ultrasound), thyroid I-131 uptake, and I-131 half-life. The follow-up period was 1 year and included measurements of thyroid size and function and patient satisfaction. Results: Baseline median goiter volume was 51 mL (range, 20-99 mL) in the placebo group and 59mL( range, 25-92 mL) in the thyrotropin group (P = .75). At 12 months, the mean +/- SEM relative goiter reduction was 46.1% +/- 4.0% in the placebo group and 62.1% +/- 3.0% in the thyrotropin group (P = . 002 between groups). The difference was most pronounced among patients with large goiters. Within each group, there was no significant correlation between retained thyroid I-131 dose and goiter reduction. Adverse effects were significantly more frequent in the thyrotropin group (34 vs 12 events; P < . 001). Permanent hypothyroidism developed in 3 patients (11%) in the placebo group compared with 16 patients (62%) in the thyrotropin group (P < . 001). Patient satisfaction was high and uninfluenced by the use of recombinant human thyrotropin. Conclusions: Stimulation with recombinant human thyrotropin prior to I-131 therapy improves thyroid size reduction by 35%, with a 5-fold higher rate of hypothyroidism. These effects are, at least partially, mediated through mechanisms other than an increase in retained I-131 thyroid dose. Further recombinant human thyrotropin dose-finding studies are warranted before routine use.