RADIOIODINE TREATMENT OF MULTINODULAR NONTOXIC GOITER

Objective-To investigate the long term effect of radioactive iodine on thyroid function and size in patients with non-toxic multinodular goi tre. Design-Consecutive patients with multinodular non-toxic goitre se lected for radioactive iodine treatment and followed for a minimum of 12 months (median 48 months) after an intended dose of 3.7 MBq/g thyro id tissue corrected to a 100% uptake of iodine-131 in 24 hours. Patien ts-69 patients with a growing multinodular non-toxic goitre causing lo cal compression symptoms or cosmetic inconveniences. The treatment was chosen because of a high operative risk, previous thyroidectomy, or r efusal to be operated on. Main outcome measurements-Standard thyroid f unction variables and ultrasonically determined thyroid volume before treatment as well as 1, 2, 3, 6, and 12 months after treatment and the n once a year. Results-56 patients were treated with a single dose of I-131, 12 with two doses, and one with four doses. In 45 patients trea ted with one dose and remaining euthyroid the median thyroid volume wa s reduced from 73 (interquartile range 50-106) ml to 29 (23-48) ml at 24 months in the 39 patients in whom this was measured during follow u p. The median reduction was 40 (22-48) ml (60% reduction, p<0.0001), h alf of which occurred within three months. Patients treated with two d oses as well as those developing hypothyroidism and hyperthyroidism ha d a significant reduction in thyroid volume. Eleven patients developed hypothyroidism (cumulative five year risk 22%, 95% confidence interva l 4.8% to 38.4%). Side effects were few: three cases of hyperthyroidis m and two cases of radiation thyroiditis. Only one patient was dissati sfied with the result; she was referred for operation six months after treatment. Conclusions-A substantial reduction in thyroid volume acco mpanied by a low incidence of hypothyroidism and few side effects make s the use of radioactive iodine an attractive alternative to surgery i n selected cases of non-toxic multinodular goitre.