With PDT, will radiation still have a role in AMD treatment?

INDIANAPOLIS, Ind. — The role of radiation therapy in treating patients with exudative age-related macular degeneration is in question now that photodynamic therapy is an available treatment option. A randomized study here found no significant benefit of radiation treatment, and enrollment in the study was halted when regulatory approval of PDT was anticipated.

Thomas Ciulla, MD, and colleagues here at the Indiana School of Medicine randomly assigned 37 patients with subfoveal choroidal neovascularization (CNV) membranes due to AMD to 16-Gy proton irradiation delivered in two fractions 24 hours apart or to sham control treatment. The researchers halted enrollment at 37 patients for ethical reasons because at the time, Food and Drug Administration approval of Visudyne (verteporfin for injection, Novartis Ophthalmics) was imminent.

All patients underwent a baseline examination. The location and dimension of the CNV membranes were confirmed on fluorescein angiography performed within 1 week of radiation treatment. Both treated and control patients underwent visual function reassessment along with photography and fluorescein angiography at 3, 6, 12, 18 and 24 months.

Both the treated and the placebo group exhibited stable vision at 12 months. Proton irradiation was associated with a trend toward stabilization of visual acuity, but the trend did not reach statistical significance, the study authors noted.

“Future studies will require more complex design and a larger sample size to determine whether radiation can play either a primary or adjunctive role in treating these lesions,” the authors wrote in the December issue of American Journal of Ophthalmology.