Abstract
Radioiodine therapy (131I) has been reported to trigger worsening of thyroid-associated orbitopathy (TAO), although pre-treatment with steroids has been shown to be effective in preventing the reactivation of disease. Aim of the present study was to evaluate the effect of 131I with or without preventive steroid treatment on the clinical course of TAO. 114 Graves’disease (GD) and TAO patients were retrospectively studied. In all patients, we have measured serum TSH-receptor antibodies (TRAb) and thyroid hormone concentrations and carried out an ophthalmological assessment of disease activity, with the clinical activity score (CAS).Eighty out of 114 patients underwent 131I without steroids treatment because they had inactive TAO (group A), and 34 patients were pre-treated with steroids (oral prednisone or i.v. methylprednisolone), seven because of persistently active TAO and 27 because considered at risk for reactivation (group B). Twenty-three patients of group A and 16 of group B were smokers (P=n.s.). The mean (±SD) CAS before radioiodine was 0.6±0.6 in group A and 1.8±1.4 in group B (P=0.002). Mean (±SD) serum TRAb concentration in group A was 20.7±40.4 and in group B 16.5±20.8 (P=n.s.). Relapse of TAO was observed in six of 80 (7.5%) of patients of group A and in 11 of 34 (32.3%) patients of group B (P<0.0007). In both groups of patients TAO relapse was associated with a shorter disease duration (P=0.04), while no difference was found in pretreatment T3 levels, TRAb concentrations or prevalence of smokers (P=n.s.). In conclusion, steroid pre-treatment is not always be effective in preventing relapse of active TAO after radioiodine therapy. In addition, there may be a risk of TAO reactivation also in patients with inactive ocular disease, in particular in those with a shorter disease duration. Our findings suggest that radioiodine must be used with caution in patients with recent or active TAO.