Purpose: The aim of this study is to evaluate the response of Graves' orbitopathy to irradiation, and to specify the prognostic factors allowing one to better define the indications of orbital radiotherapy.
Methods and materials: From 1977 to 1996, 199 patients received bilateral orbital irradiation delivering 20 Gy in 10 fractions and 2 weeks for a progressive Graves' orbitopathy. 195 patients were seen between 1 and 6 months after radiotherapy. The different symptoms were studied and their response to radiation was analyzed. Factors such as age, sex, evolution of thyroid disease, history of symptoms, and previous or combined treatments were analyzed.
Results: The results revealed that 50 patients (26%) had a good or excellent response, 98 (50%) had a partial response, 37 (19%) were stable, 10 (5%) had a progression of disease. The signs that best responded to radiotherapy were the infiltration of soft tissues and the corneal involvement. Responses of proptosis or oculomotor disorders were more complete when these signs were not advanced at the time of treatment. Irradiation seemed to have the same efficacy when applied as first-line treatment or after failure of corticosteroids. Neither modality of treatment of hyperthyroidism nor thyroid status at the time of orbital irradiation modified the results. The best results were recorded for early or moderately advanced presentation (p = 0.05). Patients treated within a delay of 7 months after the beginning of the ophthalmopathy had better responses than patients treated later (p = 0.10).
Conclusion: Radiation therapy was successful in Graves' orbitopathy by stopping the progression of disease in almost all cases, by improving the comfort of patients, by obtaining objective responses, and by avoiding surgical treatments particularly when signs were moderate.