Safety and efficacy of administering 0.2 mg of recombinant human TSH for two consecutive days as an adjuvant to therapy with low radioiodine doses in elderly out-patients with large nontoxic multinodular goiter

AIM: The aim of this study was to evaluate the efficacy of recombinant human TSH (rhTSH) as an adjuvant to radioiodine therapy for nontoxic multinodular goiter (MNG) in elderly subjects. METHODS: Twelve elderly out-patients with large MNG (group 1) were studied. The effect of adjuvant rhTSH administration (0.2 mg i.m. on 2 consecutive days) before low-dose (131)I was compared with that of radioiodine alone in 8 out-patients matched for age and MNG volume (group 2). The follow-up period was similar in both groups. RESULTS: The number and severity of side-effects during the first month of treatment were similar in both groups. On final examination, the number of patients symptomatic for goiter was significantly lower in group 1 than in group 2 (P=0.03). In group 1, TSH levels peaked at 40.3+/-9.5 mU/L on day 3, from the baseline value of 0.5+/-0.1 mU/L (P<0.001). In group 2, baseline TSH was 0.4+/-0.1 mU/L. Although a marked increase in f-T3, f-T4 and Tg (P<0.001) was noted in both groups during the first 2 weeks of treatment, peak values were much higher in group 1 than in group 2. On final examination, a slightly significant increase (P=0.01) in TSH levels from the baseline was noted in both groups (group 1: 1.2+/-0.2 mU/L; group 2: 1.4+/-0.3 mU/L). The percentage of patients who did not need therapies to control TSH secretion at the last examination was higher in group 1 (83%) than in group 2 (38%). Only in group 1, a significant reduction was noted in mean anterior-posterior lobar width (31+/-1.7 mm) from the baseline value (24.5+/-1.7 mm, P=0.04). Thyroid volume was reduced from 78.1+/-11.7 mL to 49.4+/-13.4 mL (P=0.001) in group 1 and from 89.8+/-25.2 mL to 67.1+/-20.5 mL (P=0.04) in group 2. Six months after (131)I therapy, slight changes in thyroid length and tracheal lumen were noted in both groups. CONCLUSIONS: This long-term controlled study demonstrates that 0.2 mg of rhTSH on 2 consecutive days increases the efficacy of ambulatory (131)I dosages in treating nontoxic MNG in elderly subjects. Adequate drug preparation generally prevents side-effects due to short-term but marked thyrotoxicosis that is aggravated by rhTSH administration. An increase in thyroid volume reduction seems to be the most important effect of rhTSH administered before (131)I.