Dose Response in the Treatment of Subfoveal Choroidal Neovascularization in Age-Related Macular Degeneration: Results of a Phase I/II Dose-Escalation Study Using Proton Radiotherapy

Approximately 20% of patients with subfoveal choroidal neovascularization qualify for laser photocoagulation, a treatment associated with both disease control and reduced visual acuity. No proved treatment exists for other patients. Single-fraction proton therapy was investigated as an alternative for two groups of patients: 21 patients received 8 GyE; 27 received 14 GyE. Follow-up by fluorescein angiography, visual acuity, contrast sensitivity, and reading speed were done (mean duration: 16 months). Actuarial lesion control at 21 months was 36% for 8-GyE patients and 89% for 14-GyE patients; 77% of patients with controlled lesions achieved improved/stable visual acuity, compared to 44% with uncontrolled lesions. Actuarial mean visual loss for proton-treated maculas was zero at 24 months. No treatment-related morbidity supervened, based on Radiation Therapy Oncology Group criteria. Proton therapy of 14 GyE in one fraction appears to be more effective in controlling neovascular macular degeneration than 8 GyE in one fraction, for both laser-ineligible and -eligible patients.