Radiotherapy for Graves' Ophthalmopathy: When is the Optimal Timing of Treatment and Evaluation

Purpose: Despite the decades of using radiotherapy 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 radiotherapy by assessing steroid requirement after radiotherapy in patients without prior surgery.

Methods and materials: Between 2008 and 2022, we analyzed 74 patients with Graves' ophthalmopathy who received radiotherapy 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 two or more 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, one month after radiotherapy (p<0.001). However, diplopia showed significant improvement at a relatively late phase, 4 months after radiotherapy (p=0.039). Patients treated with steroids concurrently showed a faster response compared to those without steroids. Initiating radiotherapy within 12 months of symptom onset resulted in a shorter duration of steroid use after radiotherapy compared to later initiation (65 vs. 286 days, p=0.011).

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