Radiotherapy for Graves' ophthalmopathy: results at one year.

We report on a prospective, randomized, double-masked, internally controlled, clinical trial of external beam radiotherapy for patients with mild to moderate Graves' ophthalmopathy. Forty two patients entered the study and after giving informed consent had radiotherapy to one randomly selected orbit and sham radiotherapy to the other side. Six months later the alternate orbit was treated. Neither the patient nor those assessing treatment response were aware of which orbit had been treated. Measurements made included: lid fissure width, range of extraocular muscle motion, area of diplopia fields, volume of extraocular muscle and fat, proptosis. Patients were seen at three month intervals on a rigid follow up schedule. Six months after study entry no evidence of clinically or statistically significant benefit from radiotherapy was apparent in any measured parameter in the treated versus the untreated orbit. Patients treated six months earlier in the course of their illness fared no better than patients treated later. Previous steroid therapy and the value of the clinical activity score did not affect outcome. Since orbital radiotherapy is not free of risk and does not appear to be effective, it's place in therapy of Graves disease should be reassessed.