Combined radiotherapy and medical immunosuppression in the management of thyroid eye disease.

Abstract

Although systemic steroids or orbital radiotherapy are effective in limiting the inflammatory response in thyroid eye disease (TED), there are reports of over 70% of treated patients requiring subsequent rehabilitative surgery: either orbital decompression or strabismus correction. This study investigated whether combined immunosuppression with primary orbital radiotherapy together with azathioprine and low-dose prednisolone, applied early in the active disease state, was more effective in treating TED. Forty consecutive patients with active TED were recruited. Orbital MRI (STIR sequence) was used to assess disease activity. Median duration of symptoms was 1.0 year. Subjects were treated with bilateral orbital radiotherapy (20 Gy in 10 fractions) and oral prednisolone and azathioprine. Pre- and post-treatment activity was measured clinically, including uniocular field of fixation, Mourits score and total eye score, until TED became inactive off all treatment. Before treatment, 15 subjects had signs of dysthyroid optic neuropathy, 35 had significant motility restriction and 38 had marked soft tissue signs. On average TED became inactive after 1.2 years (SD 0.7) of immunosuppression, and treatment was well tolerated. One patient required subsequent cosmetic orbital decompression, 6 had successful strabismus surgery and 13 required minor cosmetic lid surgery. Compared with previously reported treatment regimes we think that combined orbital radiotherapy and medical immunosuppression is far more effective than either treatment alone in the management of active TED, and led to fewer side effects of high-dose steroids. In particular there was more than a four-fold reduction in the requirement for orbital decompression and strabismus surgery.