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Results of a prospective, randomized, controlled, double-blind multicenter trial on external beam radiation therapy for subfoveal choroidal neovascularization secondary to ARMD (RAD-Study)
F. G. Holz for the RAD-Study Group
Purpose: To determine the efficacy of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD).
Methods: A randomized, double-blind, 'placebo'-controlled, multicenter trial was performed at 9 ophthalmic and radiotherapeutic centers throughout Germany. Two hundred five patients were randomly assigned either to treatment with 8 fractions of 2 Gy 6 MV external beam photons (n=101) or to control with 8 fractions of 0 Gy ('placebo'-radiation, n=104). Both patients and ophthalmologists were blinded with regard to applied treatment. Patients with subfoveal classic or occult CNV, visual acuity better than or equal 20/230 on the ETDRS-chart, lesion size less or equal 6 disc areas, history of visual symptoms less or equal 6 months, and absence of foveal hemorrhage were recruited. Visual acuity and contrast sensitivity testing, clinical examination, and fluorescein angiography were evaluated, with the main outcome measure being the difference in visual acuity between baseline and after 1 year of follow-up.
Results: 178 patients (86.8%) completed the 1-year follow-up. The mean reduction in visual acuity was 3.4 ± 4.6 lines in the 8x2 Gy treatment group and 3.7 ± 3.9 lines in the 8x0 Gy control group. This difference was not statistically significant (P = 0.48, Mann-Whitney-U-test). At 1 year, 49 % of treated patients and 48 % of controls lost 3 or more lines (P = 0.89). Visual acuity in 68 patients with classic CNV dropped by 3.7 ±.4.3 in the treatment group vs. 4.4 ± 3.9 in the control group (P = 0.43). Visual acuity in 110 patients with occult CNV dropped from 3.2 ± 4.2 in the treatment group vs 3.3 ± 3.8 in the control group (P = 0.68). After 2 years (128 patients; 62,4 %) mean reduction in visual acuity was 4,6 ± 4,7 lines in the treatment compared to 5,5 ± 4,4 lines in the control group (P = 0,97).
Conclusions: In this randomized study radiation therapy at a dose of 8 fractions of 2 Gy provided no benefit as a treatment for subfoveal CNV secondary to ARMD.
Department of Ophthalmology, University of Heidelberg, INF 400, D-69120 Heidelberg, Germany; supported by DFG grant Vo 437/3-1