Radioiodine treatment of non-toxic multinodular goitre: effects of combination with lithium

Purpose This study aimed to evaluate the effects of radioiodine (¹³¹I), alone or in combination with lithium, on thyroid volume and the prevention of radioiodine-induced thyrotoxicosis. This is the first clinical trial including only patients with multinodular goitre, normal TSH values and negative anti-thyroid auto-antibodies at baseline.Methods Eighty consecutive patients were randomised to receive ¹³¹I plus lithium (group I+L) or ¹³¹I alone (group I). Thyroid ultrasonography and biochemical analyses were performed at baseline and at 1, 3, 6, 12 and 24 months after treatment.Results At 1–4 weeks after treatment, ¹³¹I-induced hyperthyroidism was observed in 58.8% of patients and was prevented by lithium administration. A low incidence of hypothyroidism (19%) was recorded at 24 months, whereas up to 44% of patients developed anti-thyroid antibodies. A significant reduction in thyroid volume was observed after ¹³¹I, with a mean decrease of 47.2% (median 48.2%) at 24 months, without differences between the groups. Moreover, it was shown that the decrease in thyroid volume after ¹³¹I was also due to the significant shrinkage of thyroid nodules.Conclusion This demonstrates that adjunctive lithium is able to reduce radioiodine-induced hyperthyroidism. Therefore, such treatment appears to be safe in older patients and those with underlying cardiovascular disease. In the present large series, ¹³¹I therapy was demonstrated to be highly effective in reducing thyroid and nodular volume even in patients treated with low ¹³¹I doses (2.5 MBq/ml of thyroid tissue), further supporting the view that radioiodine therapy represents a real alternative to surgery.