Enhancing the efficacy of I therapy in non-toxic multinodular goitre with appropriate use of methimazole: an analysis of randomized controlled study.

PURPOSE

It is possible to raise the rate of the uptake of I in the thyroid gland (RAIU) by increasing the endogenous TSH level through appropriate use of methimazole (MMI) prior to I therapy. The purpose of this paper is to assess the impact of pre treatment with MMI on the efficacy of I therapy in non-toxic multinodular goitre (NMG).

METHODS

Thirty-one patients with NMG received I treatment in order to reduce the volume of the thyroid (TVR). Those in group 1 (n = 16) were administered 10 mg of methimazole for 6 weeks. Four days after its discontinuation, they received I. Patients in group 2 (n = 15) were given a placebo instead of MMI. The therapeutic activity of I was constant (800 MBq) and was repeated every 6 months. Treatment was discontinued when TVR reached <40 ml.

RESULTS

In group 1, RAIU increased approximately twofold. Ten patients from group 2 and four patients from group 1 received further doses of I. The median of time until TVR decreased below 40 ml was 9 months [6-12 months] and 18 months [14-22 months] in group 2. At 2 years after the I therapy, the occurrence of hypothyroidism did not differ significantly (36% in group 1 and 33% in group2, p = 0.074).

CONCLUSIONS

Radioiodine treatment of NMG preceded with appropriate application of MMI is efficient thanks to increased RAIU, shorter period of treatment, and lower frequency of I administration, without an increase in the incidence of post-treatment hypothyroidism.