Recombinant Human Thyrotropin as Adjuvant in the Treatment of Multinodular Goiters with Radioiodine

Abstract

The use of 131I in the treatment of multinodular goiters (MNG) is well established. We evaluated the effect of 30 microCi 131I (1.11 GBq) in 18 patients with MNG with the aid of two injections of 0.1 mg recombinant human TSH (rhTSH), given on d 1 and 2. A dose of 30 microCi 131I was given on d 3. TSH, T3, free T4, and thyroglobulin were measured on d 1, 2, 3, 5, 10, 30, 60, 90, and 180, and antithyroid antibodies were measured on d 1, 30, 90, and 180. Twenty-four-hour 131I uptake measured 1-3 months before rhTSH increased from 12.3 +/- 6.2 to 53.5 +/- 10.9% (P < 0.0001), free T4 from 1.3 +/- 0.2 to peak 3.2 +/- 1.1 ng/dl levels (P < 0.0001), T3 from 113.9 +/- 35.0 to peak 332.2 +/- 123.0 ng/dl levels (P < 0.0001), TSH from 0.76 +/- 0.71 to peak 18.9 +/- 5. 3 mU/liter levels (P < 0.0001), and thyroglobulin from 280.9 +/- 370.0 to peak 1838.5 +/- 1360.7 ng/dl levels (P = 0.001). Painful thyroiditis (33%) and mild thyrotoxicosis (39%) constituted minor side effects. There were no changes in echocardiographic parameters, done before and after rhTSH administration, on d 3. Hypothyroidism developed in 65%. Mean goiter size, measured by computed tomography, decreased from 97.9 +/- 45.4 to 65.5 +/- 47.3 ml (P < 0.0001; reduction: 39 +/- 19%) after 6 months. We conclude that rhTSH is a safe and efficient therapeutic tool in the treatment of MNG allowing the use of outpatient therapeutic 131I doses.

Latin American Thyroid Society recommendations for the management of thyroid nodules

“…Several doses of rhTSH have been tested yielding similar results, with an average reduction in gland size of 40% to 50% over 6 to 12 months (43)(44)(45)(46)(47). New studies are necessary to address the adequate rhTSH dose and the correct radioiodine dose to obtain the best results with lowest adverse events (thyrotoxicosis, goiter enlargement or local pain).…”

Single, very low dose (0.03 mg) of recombinant human thyrotropin (rhTSH) effectively increases radioiodine uptake in the I-131 treatment of large nontoxic multinodular goiter

“…The studies described so far have used doses from 0.005 mg to 0.9 mg. The injections have been performed once, 2-24 hours before the administration of I-131, or twice, at an interval of 24 hours [26,[30][31][32][33][34].…”

“…After intramuscular administration of 0.1 mg of rhTSH performed twice (over two consecutive days) the mean RAIU increased from the baseline 35% only to 45% [36]. Only Albino et al found a significantly higher (as compared with other studies) increase in RAIU as it grew 4.5 times after 0.1 mg of thyrotropin was administered twice [30]. In other papers, authors suggested the use of 0.45 mg of rhTSH, achieving a 151% increase in iodine uptake [37].…”

Radioiodine therapy in non-toxic multinodular goitre. The possibility of effect-amplification with recombinant human TSH (rhTSH)

“…A high dietary iodine intake also makes 131 I therapy less feasible. However, the recent advent of recombinant human TSH (rhTSH) which has the potential of increasing the 24-hour 131 I uptake by more than four-fold [48] opens new avenues. The effect is inversely correlated to the initial thyroid 131 I uptake RAIU, meaning that patients with the lowest 131 I uptake benefit most from rhTSH stimulation [48 Á 50].…”

“…Pretreatment with rhTSH causes a more homogeneous distribution of 131 I within the nodular gland by stimulating the 131 I uptake relatively more in cold areas than in hot areas [51]. Recent studies have investigated whether rhTSH stimulation influences the effect of 131 I therapy in patients with benign nodular goitre [48,52,53]. Only one of these was randomized [53].…”