Prolonged follow‐up of multinodular goitre patients treated with radioiodine preceded or not by human recombinant TSH

We really enjoyed the comprehensive review on the effects of recombinant human thyrotropin (rhTSH) in normal subjects and patients with goitre, by Nielsen et al . 1 in the December issue of Clinical Endocrinology 2004. In that paper it was mentioned that changes in thyroid volume of multinodular goitre patients treated with radioiodine (RAI) preceded by rhTSH were significantly higher, compared with the group that only received RAI. 2 We would like to present our results in the prolonged follow-up of MNG patients subdivided in the same two groups, namely, with prestimulation with rhTSH prior to 131 I therapy (rhTSH + RAI group) or 131 I therapy alone (RAI group). In all patients we have obtained, on a yearly basis, a computerized tomography estimate of the thyroid volume. We were able to follow up for an additional 3 years, 17 patients of the rhTSH + RAI group and 13 patients of the RAI-only group. Three elderly patients in this latter group died from cardiac disease and one was lost to follow-up. Thyroid function tests, serum antithyroid antibodies and serum Tg were also assayed. As mentioned in the paper by Silva et al ., 2 about 65% of the hrTSH + RAI and 22% of the RAI-only developed hypothyroidism in the first 12 months of follow-up and were treated with  -thyroxine. During the next three years, two additional patients (one in each group) had clinical and laboratory data that confirmed hypothyroidism and were also started on  -thyroxine. A relatively small percentage of patients (< 3%) may develop elevated anti-TPO and TSH-receptor antibodies with clinical signs of Graves’ disease. 3–5 Nineteen patients from both groups had a transient positive serum TRAb test, but no signs or symptoms of Graves’ disease. We conclude that autoantibodies to thyroid antigens may appear transiently in the prolonged follow-up of MNG patients treated with RAI. As can be observed in Fig. 1, there was a further decrease of the thyroid volume in both groups at the end of the 4-year period, but it was significantly more pronounced in the rhTSH + RAI group as compared with the RAI-only group. The higher volume reduction in rhTSH + RAI group happened during the first year after RAI treatment. During the additional 3 years, the volume reduction continued, but there was no significant difference between the groups (thyroid volume reduction: RAI group 19·6 ± 18·9%; rhTSH + RAI group 17·3 ± 18·5%; P = 0·49;  with repeated measures). In 12/17 rhTSH + RAI patients and 8/13 in RAI patients the final thyroid volume at 4 years was reduced to about 20% of the 12 months MNG volume. In the RAI group, we also observed that in 2/13 patients, the 4-year volume actually increased as compared with the 1-year volume, respectively, from 123 and 129 ml in 1 year to 132 and 138 ml in 4 years. In conclusion, although no additional benefit of one treatment over another is observed in the following 3 years of follow-up, the initial difference in thyroid volume reduction is maintained.