[Radiation therapy for Graves' ophthalmopathy]

Abstract

External irradiation for thyroid eye disease has been employed for more than three decades. Destruction of infiltrating lymphocytes in the retroorbital tissue may account for its beneficial effects. Using high voltage X-ray generated from linear accelerator, usually a total dose of 20 Gy is delivered to both orbits in 2 Gy daily fractions. This therapy is devoid of grave side effects and can be done on outpatient bases, alone or in combination with glucocorticoid regimen. Its reported effectiveness lies between 50-70%. However, results of recent randomized controlled trials on its effects were controversial. As monotherapy, while in some studies the authors observed improvement in eye movement and/or diplopia, in another one there was no significant difference in changes of objective indices between irradiated and sham-irradiated eyes. Moreover, another controlled trial on combined therapy has failed to detect additional benefit of orbital radiation on high-dose intravenous steroid pulse treatment. To ascertain its true effectiveness and indication, multicenter trials with large number of subjects seems necessary.