Strontium Plaque Brachytherapy for Exudative Age-Related Macular Degeneration: Three-year results of a randomized study
Presented in part at: Association for Research in Vision and Ophthalmology annual meeting, May, 2001; Fort Lauderdale, Florida.
Received 23 June 2004; accepted 1 November 2004. published online 18 February 2005.
Objective
To determine the efficacy of strontium plaque (Sr90) brachytherapy for age-related macular degeneration (AMD) with subfoveal choroidal neovascularization (CNV).
Design
Randomized clinical trial.
Participants
Eighty-eight eyes of 86 patients with subfoveal CNV secondary to AMD were randomized either to plaque radiotherapy or to observation.
Intervention
Radiotherapy was given as episcleral brachytherapy using Sr90 plaques. Two different plaque types were used. Plaque I had a diameter of 8 mm and delivered a dose of 15 Gy at a depth of 1.75 mm in 54 minutes. With plaque II, the corresponding values were 4 mm, 12.6 Gy, and 11 minutes. The control group was observed without any treatment.
Main Outcome Measures
The primary outcome measure was visual acuity at 6, 12, 24, and 36 months. Other outcome variables were contrast sensitivity, fluorescein angiographic, and clinically evaluated changes in the macula.
Results
Eighty-two patients (84 eyes [95%]) completed the 1-year follow-up, and 80 (93%) and 74 (86%) patients completed the 2- and 3-year follow-ups, respectively. At 6 months, visual loss of ≥3 lines occurred in 20% of treated patients and 42% of control patients (P = 0.031). At 12 months, a visual loss of ≥3 lines occurred in 45% (treated) and 56% (controls) (P = 0.325); at 24 months, in 73% and 71% (P = 0.914); and at 36 months, in 80% and 84% of patients (P = 0.591), respectively. Patients irradiated with plaque I had better results: a visual loss of ≥3 lines occurred in 6% at 6 months (P = 0.008, relative to controls), in 18% at 12 months (P = 0.007), in 59% at 24 months (P = 0.348), and in 71% at 36 months (P = 0.212). In patients treated with plaque II, the corresponding values were 29% (P = 0.032), 65% (P = 0.459), 83% (P = 0.317), and 80% (P = 0.687) at 6, 12, 24, and 36 months, respectively.
Conclusions
The short-term clinical course of exudative AMD is affected by Sr90 brachytherapy, but by 12 months, there was no treatment benefit.
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