The influence of single low dose of recombinant human thyrotropin on I-131 treatment of large multi-nodular goitre

Full text of publication follows. Recombinant human thyrotropin (rhTSH) is a substance that after single intramuscular injection can increase thyroid radioiodine uptake (RAIU) and improve the results of radioiodine therapy (RIT) in patients with nontoxic multi-nodular goitre (MNG). These effects are very important especially in cases of large MNG with relatively low RAIU or contraindications to surgery. The aim of the study: the evaluation of the influence of the single low dose of rhTSH to RAIU and the effects of RIT in patients with benign large nontoxic MNG. Material and methods: 40 patients (14 male, 26 female, age 41-80 yr) with large MNG > 100 grams and with baseline RAIU < 40% (33,37±7,96%) were included to the study and divided into two groups. First group received the single intramuscular injection of 0,03 mg rhTSH and the second received placebo. The RAIU were measured again 48 hours after the rhTSH (24 hours after diagnostic dose of I-131). After this, all the patients were administered the therapeutic doses of I-131 recalculated according to new RAIU. The patients follow up was continued for minimum 12 months. Results: the mean RAIU after rhTSH increased more than twice, to 75% from 33%. One year after RIT the mean volume goitre reduction were significantly greater in group with rhTSH than in patients with placebo (48±16% vs. 37±18%). Decrease of compression symptoms has taken place earlier and was more important in patients after rhTSH. 12 months after RIT two patients stay in hypothyroid state (from the group with rhTSH), other patients are euthyroid. Conclusions: even the single very low dose of rhTSH increases the values of RAIU in significant way. Efficacy of rhTSH-augmented RIT in patients with large nontoxic MNG is greater than standard RIT. It allows to reduce administered doses of I-131, decreases the need of repeating RIT, makes the radiation adsorbed doses for whole body lower and the RIT shorter. (authors)