Long-term follow-up of treatment outcomes in Graves' disease and toxic nodular disease.

Purpose: Hyperthyroidism guidelines have not been updated over the past five years, despite numerous data on the subject, and recent studies providing a wide variation in treatment success rates. We aim to compare the effectiveness and safety of treatment modalities in patients with Graves' disease or toxic nodular disease.

Methods: Single center retrospective cohort study of Graves' disease and toxic nodular disease patients treated between 1983 and 2023.

Results: A total of 411 patients were treated for hyperthyroidism, 245 due to Graves' disease and 166 due to or toxic nodular disease, followed for a median of 7 years. In Graves' disease, 90.2% were treated with antithyroid drugs over 250 cycles, achieving 41.7% cumulative remission. Half of all relapses (50.9%) occurred in the first year, 76.3% in the first three years, and 98.3% within nine years. Treatment periods of 12-24 months showed higher remission and lower relapse rates than longer periods. I-131 was used in 103 cycles with 82.5% remission and 7.1% relapse. A total of 29 thyroidectomies resulted in 100% remission, with no relapse. In toxic nodular disease, surgery was the most frequently used treatment (54.5%), followed by I-131 (37.1%).

Conclusion: Our findings support antithyroid drugs as the preferential first-line treatment for Graves' disease, allowing for euthyroidism with minimal adverse effects. Given the propensity for relapse, we suggest a rigorous monitoring, particularly within the first three years. In toxic nodular disease, surgery should be the preferred option, with I-131 being reserved for single adenomas and small goiters.