Soft X-ray therapy of recurrent pterygium--an alternative to 90Sr eye applicators.
BACKGROUND
Analysis of effectiveness of perioperative 20 kV soft X-ray irradiation in recurrent pterygium as an alternative to postoperative 90Sr beta irradiation.


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 treatment of recurrent pterygium. Until 1995 simple excision (bare sclera technique) 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 policy to a perioperative regimen starting with a single dose of 7 Gy prior to microsurgical excision with conjunctival autograft and proceeding within 24 hours with 5 Gy single dose to the surgical bed and then every other day to a total dose of 27 Gy (47 cases, mean follow-up 31 months). Recurrence rate was calculated by Kaplan Meier method. A multivariate Cox regression analysis of prognostic factors for recurrence was performed.


RESULTS
A total of 19 recurrences were observed, 15 in the historical postoperative group and four in the perioperative group. Actuarial 2- and 5-year 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 among the pre- and postoperatively irradiated group required a new surgical procedure. In this case radiation had been terminated at 17 Gy. Actuarial rate 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 only the new treatment strategy was found to influence control rate significantly. Until now no case of severe side effects like scleral necrosis or thinning, symble-pharon, radiation-induced cataract or glaucoma were observed in both groups.


CONCLUSIONS
The combination of pre- and postoperative 20 kV X-ray therapy and microsurgical excision combined with conjunctival autograft is a highly effective treatment to prevent recurrence in the high-risk group of recurrent pterygia and can be recommended as an alternative to postoperative 90Sr beta irradiation.
Willner
J
J
Department of Radiation Therapy, University of Würzburg, Germany. willner@strahlentherapie.uni-wuerzburg.de
Flentje
M
M
Lieb
W
W
D000206:Actuarial Analysis; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011625:Pterygium / Q000532:radiotherapy* / Q000601:surgery; D011879:Radiotherapy Dosage; D012008:Recurrence; D013326:Strontium Radioisotopes / Q000627:therapeutic use*
D013326:Strontium Radioisotopes