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Unlabelled: Prestimulation with recombinant human thyroid-stimulating hormone (rhTSH) augments radioiodine (131)I therapy for benign nontoxic multinodular goiter. The purpose of this study was to determine the optimal time interval between rhTSH and (131)I administration to enhance thyroid radioactive iodine uptake (RAIU)., Methods: Patients were randomized, in a 2-factorial design, to receive either a 0.1-mg dose of rhTSH (n = 60) or placebo (n = 30) and to a time interval of 24, 48, or 72 h before (131)I administration. The rhTSH- or placebo-stimulated RAIU study was performed at 4 wk after a baseline RAIU assessment in a tertiary referral center at a university hospital. A total of 90 patients (78 women; median age, 52 y; range, 22-83 y) referred to (131)I therapy for symptomatic nontoxic goiter (median goiter volume, 63 mL; range, 25-464 mL) were included in the study. Change in thyroid RAIU was determined at 24 and 96 h after (131)I tracer administration., Results: In the placebo subgroups, RAIU did not change significantly from baseline. The mean (+/-SE) 24-h RAIU increased from 33.8% +/- 2.3% to 66.0% +/- 1.8% (111.2% increase) with a 24-h interval, from 36.8% +/- 2.1% to 64.6% +/- 2.7% (83.3% increase) with a 48-h interval, and from 33.0% +/- 2.7% to 49.6% +/- 2.5% (62.4% increase) with a 72-h interval. All within-group changes were highly significant (P < 0.001). The effect was negatively correlated with initial RAIU (r = -0.703, P < 0.001). The increase in 24- and 96-h RAIU was significantly higher in the rhTSH/24-h group than it was in the rhTSH/72-h group (P = 0.023 and 0.012, respectively) and insignificantly higher than in the rhTSH/48-h group (P = 0.37 and 0.26, respectively)., Conclusion: The effect of rhTSH on thyroid RAIU is most pronounced when administered 24 h before (131)I administration and declines with longer time intervals. Whether there is a similar time dependency for goiter reduction after rhTSH-stimulated (131)I-therapy remains to be clarified.

Unlabelled: The definitive treatment of hyperthyroidism in Europe is quite different from that in the United States. In Europe, the surgical approach is often preferred and considered safer than radioiodine treatment. European doctors usually prefer to surgically remove the thyroid and perform a pathologic examination of it. They consider it to be an essential diagnostic tool to identify possible diseases that might be associated with hyperthyroidism and even to detect the rare thyroid tumors that might be associated with thyroid hyperfunction. The aim of this study was to evaluate whether radioiodine therapy could be a risk factor for the misdiagnosis of thyroid cancer., Methods: We performed a retrospective revision of data we collected from 6647 patients (1171 [17.5%] men, 5476 [82.5%] women), all of whom underwent 1311 therapy for hyperthyroidism from 1970 to 1997. Of the whole group, 6.5% were younger than 40 y, 33.5% were 40-60 y old, and 60% were older than 60 y. Moreover, 5061 (76%) patients had either an autonomously functioning node or a toxic multinodular goiter. The other 1586 (24%) patients had Graves' disease., Results: After treatment, thyroid cancer was discovered in 10 (0.15%) patients, none of whom belonged to the group of patients with Graves' disease. Five of these patients were treated during a period from 1970 to 1980, when sonography was not routinely available. The incidence of thyroid cancer in the series of radioiodine-treated patients (150/100,000 over a 27-y period) was not significantly different from its incidence in the general population. The expected rate is 124.88 per 100,000 over a 27-y period., Conclusion: An accurate preliminary evaluation (clinical examination, sonography, and cytologic evaluation of fine-needle aspiration) is fundamental for a proper choice between radioiodine and surgical therapy.

Unlabelled: The effect of radioiodine in the treatment of nontoxic goiter is seldom evaluated quantitatively. The aim of this study was threefold: (a) to assess the effect of 131I on goiter volume, (b) to establish a relationship between CT volume reduction and the amount of radioactivity taken up by the thyroid and (b) to assess the precision of scintigraphic thyroid volume measurements., Methods: In 27 patients with sporadic nontoxic goiter, the thyroid volume was estimated from a [99mTc]pertechnetate scintigram. Two different models (cylinder model and surface model) were applied. The 131I dosage varied between 507 and 3700 MBq. In all patients, noncontrast CT scanning of the neck was performed before therapy and 1 yr after therapy., Results: The mean CT thyroid volume before therapy was 194 +/- 138 ml. A reduction was obtained in all patients and averaged 34% +/- 17%. The volume reduction measured by CT correlated well with the amount of 131I in the thyroid (r = 0.70). In thyroids larger than 200 ml, both scintigraphic volume estimation methods were imprecise. For smaller volumes, the surface model was superior. Hypothyroidism developed in 14% of the patients. No other side effects occurred., Conclusion: Iodine-131 therapy for volume reduction in nontoxic goiter is a safe and effective treatment. For scintigraphic estimation of thyroid gland volumes smaller than 200 ml, the surface model is preferred.