Evaluation of thyroid ablative therapy for ophthalmopathy of Graves' disease

Abstract

The effect of ¹³¹I ablation on the course of thyroid-associated ophthalmopathy was evaluated in a non-randomized study of 15 patients with severe symptomatic ophthalmopathy. The eye condition was stable at a severe level in three and progressive in 12, despite prior treatment including administration of steroids in seven, or use of antithyroid drugs, or radiotherapy. Thirteen had previously been treated by radioactive iodide administration, one had had a subtotal thyroidectomy, and one had euthyroid Graves' disease. At the time of ablative therapy, three were hyperthyroid, four euthyroid, and eight were receiving replacement therapy for hypothy-roidism. ¹³¹I was given to reduce 24 RAIU below 1%, and other treatments including steroids were continued, if the patient's condition appeared to require this treatment. Eleven patients appeared to have a beneficial response, and in six patients this appeared to be specifically related to ¹³¹I ablative therapy. There was an average 51% decrease in the ophthalmopathy index from preablative levels in the responders. Measurements of exophthalmos were minimally changed. There was a negative correlation between duration of exophthalmos and % improvement, and no correlation between response and antithyroid antibody titers or radioactive iodide uptake at the time of ablation. Apparent improvement occurred four to 24 months after successful ablation with an average interval of nine months.

Although an uncontrolled study cannot prove the value of this treatment, and the results are compounded by coincident treatment of these patients with severe problems, the results suggest strongly a beneficial effect in patients with progressive ophthalmopathy of recent onset who have residual functioning thyroid tissue. The beneficial response, if present, may be related to antigen deprivation. This study provides the basis for re-evaluation of this therapy in a prospective controlled manner.

Key Words:

• Thyroid ablation
• antithyroid drugs
• radioiodide
• cytotoxicity
• thyrotoxicosis