title: Comparative study of different β-radiation doses for preventing pterygium recurrence.
abstract: OBJECTIVE
  To compare the pterygium recurrence rates after treatment with two different β-radiation doses.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Ophthalmology and Visual Science, Hiroshima University Graduate School of Biomedical Sciences, and Department of Ophthalmology, Hiroshima Red Cross and Atomic Bomb Survivors Hospital, Hiroshima, Japan. tyamada-oph@umin.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamada
authors.forename: Hideki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ue
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kiuchi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Matsuyoshi
authors.initials: M
authors.lastname: Oinaka
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001610:Beta Particles / Q000627:therapeutic use*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011625:Pterygium / Q000473:pathology / Q000517:prevention & control / Q000532:radiotherapy* / Q000601:surgery; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D055502:Secondary Prevention