Effect of subtotal thyroidectomy on natural history of ophthalmopathy in Graves' disease

Graves' ophthalmopathy is a complex disease whose pathogenesis is thought to be autoimmune. The treatment of Graves' disease is considered to be related to the progression of Graves' ophthalmopathy. There have been no long-term prospective studies on the natural course of Graves' ophthalmopathy. In this study we assessed the influence of subtotal thyroidectomy on the outcome of Graves' ophthalmopathy, comparing it with that of radioactive iodine treatment. Altogether 287 untreated patients with Graves' disease referred to Ito hospital in 1989 were followed prospectively for 5 years. A group of 67 patients were treated with radioactive iodine, and 18 patients underwent surgery. Proptosis of the eyes was measured in all patients using Hertel's exophthalmometer. The mean value of proptosis in patients with untreated Graves' disease was 14. 8 +/- 0.2 mm (mean +/- SEM), and after 5 years it increased slightly to 15.0 +/- 0.2 mm. The mean changes of proptosis in patients treated surgically and patients given radioactive iodine were -0.01 +/- 0.22 and 0.93 +/- 0.28 mm, respectively (p < 0.05). In patients treated by subtotal thyroidectomy, ophthalmopathy did not change in 77.8%; it progressed in 5.6% and was alleviated in 16.7%. In patients treated with radioactive iodine, the ophthalmopathy did not change in 86.6%, progressed in 10.4%, and was alleviated in 3.0%. These findings indicate that surgery can be a better treatment than radioactive iodine for Graves' patients with ophthalmopathy.