Low or High Fractionation Dose β-Radiotherapy for Pterygium? A Randomized Clinical Trial

• Published in: International journal of radiation oncology, biology, physics Vol. 82; no. 2; pp. e181 - e185
• Main Authors: Viani, Gustavo Arruda, M.D, De Fendi, Ligia Issa, M.D, Fonseca, Ellen Carrara, M.D, Stefano, Eduardo Jose, M.D
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2012
• Subjects: Adult; Aged, 80 and over; Algorithms; Beta Particles - adverse effects; Beta Particles - therapeutic use; Dose Fractionation; Eye Diseases - etiology; Female; Granuloma - etiology; Hematology, Oncology and Palliative Medicine; Humans; Male; Middle Aged; Photophobia - etiology; Prospective Studies; Pterygium; Pterygium - pathology; Pterygium - radiotherapy; Pterygium - surgery; Radiology; Radiotherapy - adverse effects; Randomized controlled trial; Recurrence; Sclera - radiation effects; Sclera - surgery; Strontium Radioisotopes - adverse effects; Strontium Radioisotopes - therapeutic use; Treatment Outcome; Young Adult; β-radiotherapy; Pterygium; Randomized controlled trial; β-radiotherapy
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2010.11.017

Purpose Postoperative adjuvant treatment using β-radiotherapy (RT) is a proven technique for reducing the recurrence of pterygium. A randomized trial was conducted to determine whether a low fractionation dose of 2 Gy within 10 fractions would provide local control similar to that after a high fractionation dose of 5 Gy within 7 fractions for surgically resected pterygium. Methods A randomized trial was conducted in 200 patients (216 pterygia) between February 2006 and July 2007. Only patients with fresh pterygium resected using a bare sclera method and given RT within 3 days were included. Postoperative RT was delivered using a strontium-90 eye applicator. The pterygia were randomly treated using either 5 Gy within 7 fractions (Group 1) or 2 Gy within 10 fractions (Group 2). The local control rate was calculated from the date of surgery. Results Of the 216 pterygia included, 112 were allocated to Group 1 and 104 to Group 2. The 3-year local control rate for Groups 1 and 2 was 93.8% and 92.3%, respectively ( p = .616). A statistically significant difference for cosmetic effect ( p = .034), photophobia ( p = .02), irritation ( p = .001), and scleromalacia ( p = .017) was noted in favor of Group 2. Conclusions No better local control rate for postoperative pterygium was obtained using high-dose fractionation vs. low-dose fractionation. However, a low-dose fractionation schedule produced better cosmetic effects and resulted in fewer symptoms than high-dose fractionation. Moreover, pterygia can be safely treated in terms of local recurrence using RT schedules with a biologic effective dose of 24–52.5 Gy10.