Soft X-ray therapy of recurrent pterygium an alternative to Sr-90 eye applicators

Background: Analysis of effectiveness of perioperative 20 kV soft X-ray irr adiation in recurrent pterygium as an alternative to postoperative Sr-90 be ta irradiation. Patients and Methods: Between 1987 and 2000 a total of 65 patients with 81 pterygia were treated with 20 kV X-ray therapy in the course of surgical tr eatment of recurrent pterygium. Until 1995 simple excision (bare sclera tec hnique) followed by postoperative irradiation (generally four fractions of 5 Gy) was applied, with radiation starting on mean 4 days following surgery (34 cases, mean follow-up 52 months). Since 1995 we have changed our polic y to a perioperative regimen starting with a single dose of 7 Gy prior to m icrosurgical excision with conjunctival autograft and proceeding within 24 hours with 5 Gy single dose to the surgical, bed and then every other day t o a total dose of 27 Gy (47 cases, mean follow-up 31 months). Recurrence ra te was calculated by Kaplan Meier method. A multivariate Cox regression ana lysis of prognostic factors for recurrence was performed. Results: A total of 19 recurrences were observed, 15 in the historical post operative group and four in the perioperative group. Actuarial 2- and 5-yea r recurrence rate is 9% in the "new treatment group" compared to 34% and 56 % in the historical group (p = 0,001). Only one of the four recurrences amo ng the pre- and postoperatively irradiated group required a new surgical. p rocedure. In this case radiation had been terminated at 17 Gy. Actuarial ra te of surgical reintervention was only 2% at 2 and 5 years compared to 28% and 36% in the historical group. In multivariate Cox regression analysis on ly the new treatment strategy was found to influence control rate significa ntly. Until now no case of severe side effects like scleral necrosis or thi nning, symblepharon, radiation-induced cataract or glaucoma were observed i n both groups. Conclusion: The combination of pre- and postoperative 20 kV X-ray therapy a nd microsurgical excision combined with conjunctival autograft is a highly effective treatment to prevent recurrence in the high-risk group of recurre nt pterygia and can be recommended as an alternative to postoperative Sr-90 beta irradiation.