Outcome following standardized 185 MBq dose 131I therapy for Graves' disease

The clinical outcome of 199 patients with Graves' disease treated with standardized 185MBq 131I therapy doses has been analysed. Most patients were controlled with antithyroid drugs prior to the 131I therapy, and also received antithyroid drugs for several months following 131I. The median follow-up period was 5.5 years. The single 185MBq 131I dose successfully treated 72.4% of patients. The 1, 2 and 5 year hypothyroid figures were 15.5%, 19.3% and 27.3%, respectively. Previous thyroidectomy was associated with an increased hypothyroid rate. Retreatment was required by 25.6%, with 3.5% requiring more than two 131I doses. Discriminant analysis of pretreatment variables suggests that patients with large goitres or severe disease (serum T3 greater than 10nmol/l) should be treated with higher doses of 131I.