Orbital radiation therapy for Graves' ophthalmopathy: measuring clinical efficacy and impact.

Abstract

Graves' ophthalmopathy (GO) is an autoimmune condition primarily managed with prolonged courses of glucocorticoids, which can be associated with significant side effects. Orbital radiation therapy (RT) is an alternative treatment that has shown variable efficacy in improving orbital and visual symptoms. In this study, the therapeutic benefit of RT was evaluated in terms of patient's ability to taper their corticosteroid requirements, which may better reflect the proposed mechanism of RT and provide a clinically relevant response endpoint. This is a retrospective review of consecutive patients treated with orbital RT for GO between 2000 and 2010 at a single tertiary hospital with a dedicated ocular radiation therapy clinic. The primary measure of treatment response was defined as the ability to taper glucocorticoids following RT without any further exacerbation of orbitopathy symptoms. Additional endpoints including ocular symptoms (diplopia, proptosis, visual acuity, extraocular movement) and need for surgical intervention were reported. Of 86 eligible patients, with a mean follow-up of 9.3 months, 81 (94%) patients responded to RT. Of patients taking corticosteroids at baseline, 91% were able to taper off corticosteroids completely and the remaining patients had decreased their doses by 83%. Diplopia, visual acuity, and extraocular movements improved in 29%, 81%, and 58% of patients, respectively. The median reduction in proptosis was 2.5 mm and 2 mm in the left and right eyes, respectively (range, -18 mm to 23 mm). Orbital RT is a generally well-tolerated treatment that helps minimize the dose and duration of corticosteroid therapy for patients with GO while improving ocular symptoms, including proptosis and diplopia. Prospective research should consider using corticosteroid requirement as a measure of response to orbital RT for GO.