The efficacy of intensity modulated radiation therapy in treating thyroid-associated ophthalmopathy and predictive factors for treatment response.

The study evaluated clinical efficacy of intensity modulated radiation therapy (IMRT) in treating patients with thyroid-associated ophthalmopathy (TAO) and defined predictive factors that associated with treatment response. A total of 178 TAO patients were treated with retro-orbital IMRT with radiation dose of 20 Gy in 10 fractions. The immediate and long-term treatment response and complications were evaluated. Besides, logistic-regression analysis was conducted to identify possible predictive factors. TAO symptom score significantly fell from the initiation to 6-month post-treatment (P < 0.001). 134 patients (73.2%) had mild to significant response to IMRT, and 172 patients (96.6%) achieved stabilization of TAO without future progression. Current smoker (OR 2.88, 95% CI 1.32-6.29; P = 0.008) and symptom duration longer than 18 months (OR 3.33, 95% CI 1.24-8.93; P = 0.017) were identified as independent predictive factors for non-response of TAO to retro-orbital IMRT. Immediate complications were slight and self-limited, and long-term complications mainly included chronic xerophthalmias in12 patients (6.74%) and cataract formation in 4 patients (2.25%). The study suggested that IMRT was a viable option for treating TAO patients, with a satisfactory symptom control ability and acceptable post-treatment complications.