Radiation Therapy for Graves' Ophthalmopathy: When Is the Optimal Timing of Treatment and Evaluation.

Purpose: Despite the decades of using radiation therapy (RT) for Graves' ophthalmopathy, the effects and optimal timing remain unclear. We retrospectively analyzed to evaluate the overall efficacy and response, predictive factors, and the effective timing of RT by assessing steroid requirement after RT in patients without prior surgery.

Methods And Materials: Between 2008 and 2022, we analyzed 74 patients with Graves' ophthalmopathy who received RT to both orbits. Concurrent steroid therapy was administered to 51 patients. Symptoms were evaluated using a modified clinical activity score (CAS), defining responders as those with a ≥2 score improvement in CAS, diplopia, or a significant reduction in exophthalmos asymmetry. Common symptoms included eye swelling (81.1%), and conjunctival edema (81.1%). Diplopia observed in 48 patients (64.9%).

Results: Median follow-up was 44.5 months (range, 4.8-169.6). CAS significantly improved in the early-immediate phase, 1 month after RT (P < .001). However, diplopia showed significant improvement at a relatively late phase, 4 months after RT (P = .039). Patients treated with steroids concurrently showed a faster response compared to those without steroids. Initiating RT within 12 months of symptom onset resulted in a shorter duration of steroid use after RT compared with later initiation (65 vs 286 days, P = .011).

Conclusions: Our study suggests an evaluation period of at least 4 months after RT regardless of concurrent steroid treatment, recognizing the prolonged improvement timeline for diplopia. Additionally, for reducing steroid use after RT, our study suggests optimal timing of RT within 12 months of symptom onset.