Purchase this article with an account.
Rachel M. Huckfeldt, Eugene Shildkrot, Anne Marie Lane, Evangelos Gragoudas, Joan W. Miller; Proton Beam Irradiation for Choroidal Neovascularization: Long-term Prevalence of Radiation Retinopathy. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5834.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the prevalence of radiation retinopathy 10 years after proton beam irradiation for subfoveal choroidal neovascularization (CNV).
A retrospective chart review was conducted of patients treated with proton irradiation in a 2 year randomized trial of 16-cobalt gray equivalent (CGE) vs. 24 CGE for subfoveal CNV. Between 1995 and 1999, 261 eyes from 254 patients were enrolled in the trial. Follow-up of 9.5 years or more was required for inclusion in the current study resulting in a cohort of 28 eyes from 26 patients (10 eyes with AMD, 10 eyes with myopic degeneration, 8 with other non-AMD causes). Evaluation of radiation retinopathy was based upon fundus imaging and clinical examination records. Associations between baseline characteristics and radiation retinopathy were assessed using the Wilcoxon rank sum test (continuous variables) and Fisher’s exact test (categorical variables).
Radiation retinopathy was identified in nine eyes from eight patients (32%). The most common manifestation was intraretinal hemorrhage (7 of 9 eyes) followed by hard exudates (5 of 9) and microvascular changes (5 of 9). One of the eight patients with radiation retinopathy also had a diagnosis of diabetes but no evidence of diabetic retinopathy in the untreated eye. Patients who later developed radiation retinopathy presented with larger subfoveal CNV lesions (4.3 MPS DAs) than patients who did not develop retinopathy (2.6 MPS DAs) (p=0.048). There were no differences in the occurrence of radiation retinopathy by age at treatment (p=0.48), underlying disease (p=0.40), or by radiation dose (p=0.21). Five of the 9 cases of radiation retinopathy developed after the initial 2-year study period.
Radiation has been proposed as an adjuvant treatment for CNV because of its anti-angiogenic and anti-inflammatory effects. In comparison to other strategies, proton beam therapy delivers a more focused dose of radiation to a target lesion with less disruption of surrounding tissues. However, radiation retinopathy is a significant complication of all treatment modalities, and the current data demonstrate that it may develop many years after initial proton beam therapy.
This PDF is available to Subscribers Only