Strontium plaque brachytherapy for exudative age-related macular degeneration: three-year results of a randomized study

Abstract

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 > or =3 lines occurred in 20% of treated patients and 42% of control patients (P = 0.031). At 12 months, a visual loss of > or =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 > or =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. This article contains additional online-only material available at http://www.ophsource.org/periodicals/ophtha.