Effects of total thyroid ablation versus near-total thyroidectomy alone on mild to moderate Graves' orbitopathy treated with intravenous glucocorticoids.

Abstract

Graves' orbitopathy (GO) is probably caused by autoimmune reactions against autoantigen(s) shared by thyroid and orbital tissues sustained by intrathyroidal autoreactive T-lymphocytes infiltrating the orbit. Total thyroid ablation (TTA) may be beneficial for GO through removal of shared antigen(s) and autoreactive T-lymphocytes, but randomized studies are lacking. Our objective was to evaluate the effects of TTA in patients with GO treated with iv glucocorticoids (GC). A prospective, single-blind, randomized study was conducted at a referral center. Sixty patients with mild to moderate GO were randomized into: 1) near-total thyroidectomy (TX); or 2) TX plus (131)I (TTA) groups, and then treated with iv GC. Patients were evaluated 3 and 9 months after iv GC. Overall improvement of GO at 9 months was the main outcome measure. The distribution of GO outcome at 9 months was significantly more favorable in TTA than in TX patients (P = 0.0014 by chi(2) test). A cumulative significant (P = 0.0054) difference between the two groups at 3 and 9 months was found using a generalized linear model. Radioiodine uptake test and thyroglobulin assay in a patient sample showed complete ablation in the majority of TTA, but not of TX patients. Compared with thyroidectomy alone, TTA is followed by a better outcome of GO in patients given iv GC. Whether TTA maintains this advantage in the long-term remains to be established.