A prospective, randomized, double-masked trial on radiation therapy for neovascular age-related macular degeneration (RAD study)

Objective: To determine the efficacy of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degener ation (ARMD), Design: Multicenter, parallel, randomized, double-masked clinical trial per formed at nine ophthalmic and radiotherapeutic centers. Participants: Two hundred five patients were randomly assigned either to tr eatment with 8 fractions of 2 Gy external beam irradiation (n = 101) or to control with 8 fractions of 0 Gy (sham treatment, n = 104). Both patients a nd ophthalmologists were masked with regard to applied treatment. Patients with subfoveal classic or occult CNV, visual acuity of 20/320 or greater on the Early Treatment Diabetic Retinopathy Study chart, lesion size of 6 dis c areas or less, history of visual symptoms of 6 months or less, and absenc e of foveal hemorrhage were recruited. Intervention: In the treatment group, external beam irradiation with 8 frac tions of 2 Gy was performed, whereas in the control group, sham treatment w ith 8 fractions of 0 Gy was applied, Main Outcome Measures: Primary outcome measure was the difference in visual acuity between baseline and after I year of follow-up. Results: One hundred eighty-three patients (89.3%) completed the 1-year fol low-up. The mean reduction in visual acuity was 3.5 +/- 4.7 lines in 88 pat ients of the 8- x 2-Gy treatment group and 3.7 +/- 3.8 lines in 95 patients of the 8- x 0-Gy control group, This difference was not statistically sign ificant (P = 0,53, Mann-Whitney U test), At 1 year, 51.1% of treated patien ts and 52.6% of control subjects lost three or more lines (P = 0,88), Visua l acuity in the presence of classic CNV dropped by 3.7 +/- 4.4 lines in 33 patients of the treatment group versus 4.3 +/- 3.9 lines in 36 patients of the control group (P = 0.47). Visual acuity in 114 patients with occult CNV dropped by 3.4 +/- 4.9 in the treatment group (55 patients) versus 3.4 +/- 3.8 lines in the control group (59 patients) (P = 0.80). Conclusions in this randomized study, radiation therapy at a dose of 16 Gy applied in 8 fractions of 2 Gy provided no benefit as a treatment for subfo veal CNV secondary to ARMD at 1 year.