Comparative study of different β-radiation doses for preventing pterygium recurrence.

Abstract

To compare the pterygium recurrence rates after treatment with two different β-radiation doses. A total of 84 patients with a mean age of 63.0±10.3 years (men, 48 eyes, and women, 47 eyes) and initially treated with β-radiation after pterygium excision were recruited. The mean follow-up period was 49.9±51.3 months. The patients were assigned to two dose groups: a high-dose (40 Gy) or a low-dose (20 Gy) group. The statistical significance of differences in patient age, pterygium size, and interval between surgery and radiotherapy were analyzed in the 20-Gy group using the Cox proportional hazard model at p<.05. The high- and low-dose groups included 28 and 67 eyes, respectively. Pterygia recurred in 11 eyes, all in the low-dose group. The interval between surgery and radiotherapy was not a significant predictor of recurrence. Smaller pterygia had a lower risk of recurrence than pterygia that had encroached the pupillary area (pterygium located within one-third of the corneal radius from the limbus, corrected hazard ratio [HR], 0.069; 95% confidence interval [CI], 0.006-0.766; p=.030; pterygium extending beyond one-third of the corneal radius, corrected HR, 0.188; 95% CI, 0.018-0.696; p=0.019; and pterygium reaching the pupillary area, corrected HR, 0.184; 95% CI, 0.036-0.929; p=.040). Older age was marginally significant as a negative predictor of recurrence (HR, 0.943; 95% CI, 0.887-1.003; p=.061). No scleromalacia developed during the follow-up period. β-Radiation at 40 Gy was more efficacious than at 20 Gy in preventing pterygium recurrence without scleromalacia development, particularly for large-size pterygia and those in young patients.