Radioactive iodine therapy for goitrous Hashimoto's thyroiditis

Context: Hashimoto's thyroiditis is an autoimmune disease that can produce marked clinical symptoms when patients have large diffuse goiters. Design: This retrospective cohort study was designed to evaluate whether radioactive iodine (RAI) is effective for Hashimoto's thyroiditis with a large goiter. Starting in November 1999, 13 Hashimoto's patients with large goiters, whose thyroiditis was refractory to TSH suppression therapy with thyroid hormone administration [two men and 11 women with a mean age of 61.2 +/- 8.9 yr (50 - 79 yr)], were recruited for the present study. The duration of symptomatic goiter before undergoing RAI was 12.0 +/- 7.9 yr (4 - 33 yr). Thirteen millicuries of I-131 was administered two to six times, at an interval of 1 - 6 months on an outpatient basis. Thyroid weight was measured ultrasonographically, or by computed tomography mography if ultrasound was not possible due to the large size of the goiter. Results: RAI was administered an average of 4.7 +/- 1.4 times (two to six times), with a total dose of 59.8 +/- 17.3 mCi (25.0 - 78.0 mCi). The observation period was 47.9 +/- 13.4 months (26 - 66 months) after the first RAI. The average weight of the thyroid gland was 125.3 +/- 57.7 g (42.9 +/- 269.4 g) before the first RAI, decreasing significantly to 49.7 +/- 25.8 g (18.3 +/- 93.3 g) after the last RAI (P < 0.001, paired Student's t test). The percent reduction from baseline was 58.7 +/- 14.2% (35.7 +/- 84.0%). None of the patients showed an increase in goiter size or complained of a pressure sensation after any of the RAI treatments. Conclusion: RAI is effective in Hashimoto's thyroiditis with a large goiter.