Low-dose recombinant human thyrotropin-aided radioiodine treatment of large, multinodular goiters in elderly patients

Objective: We aimed to assess low-dose recombinant human thyroid-stimulating hormone (rhTSH)-aided, fixed-activity radioiodine therapy of large, multinodular goiters (MNGs) in elderly patients with comorbidities. Design: This was a short-term, observational study. Methods: We measured 24-h thyroid radioiodine uptake (RAIU) of 2 μCi 131-iodine at baseline and 24h after intramuscular injection of 0.03 mg rhTSH in 17 patients (aged 60-86 years, 12 women), who subsequently received 30 mCi 131-iodine 24h after an identical rhTSH injection. TSH and free thyroxine (FT₄) were measured at baseline and days 10, 30 and 90 after therapy. Thyroid volume was assessed by computed tomography at baseline and day 180. Results: rhTSH, 0.03 mg, significantly increased mean 24-h thyroid RAIU from 25.8%±10.3% to 43.3%±8.4% (68% relative increase; t(16) = -8.43, P < 0.001). The proportion of patients overtly or subclinically hyperthyroid (TSH < 0.5 mU/l) decreased from 71% (12 /17) at baseline to 19% (3/16) at 3 months. Mean serum FT₄ peaked at slightly above normal range, 25.9±7.7 pmol/l (46% over baseline) and was 21% under baseline levels at 3 months. Mean estimated thyroid volume fell 34% from baseline to 6 months (170.0±112.8 to 113.1±97.5 ml; P < 0.01). Symptomatic relief, improved well-being, and/or reduction or elimination of antihyperthyroid medication were seen in 76% of patients. Three (18%) patients had transient neck pain or tenderness, or palpitations; one had transient asymptomatic thyroid enlargement; and three (18%) became hypothyroid by 3 months. Conclusions: Intramuscular rhTSH, 0.03 mg, followed 24 h later by 30 mCi 131-iodine, is a safe, effective and convenient treatment for MNG in elderly patients with comorbidities.