[Radiotherapy for choroidal neovascularization in age-related macular degeneration. A pilot study using low- versus...

Several pilot studies have indicated that low-dose radiation therapy might have a beneficial effect on the course of choroidal neovascularization (CNV) in age-related macular degeneration (AMD). This study aimed to ascertain whether such treatment might halt the progression of neovascular AMD and whether a low or a high radiation dose should be applied.

The patients comprised some randomized to 0 vs 10 vs 36 Gy of radiation and (after a change of the study protocol became necessary) others who participated in a prospective, controlled non-randomized pilot study. Enclosed were eyes with visual acuity of > or = 0.1 and < or = 0.6 revealing a juxta-subfoveal CNV either of the occult type (type 1) or the classic type (isolated or as part of a predominantly occult lesion).

Eyes treated with 10 Gy for occult CNV (n = 12) were subject to severe visual loss in 41.6% of the cases compared to 38.5% in the control group (n = 13) at 12 months of follow-up. For eyes treated with 10 Gy because of classic CNV, the corresponding figures were 33% (n = 18) and 57% (n = 14) respectively. At 18 months of follow-up, the percentages were 63% and 75% respectively. Fluorescein angiographic growth of classic and occult CNV could not be halted by 10 Gy, while a temporary growth retardation was observed in cases irradiated with 36 Gy.

In the study presented, the natural course of occult CNV could not be improved by irradiation with 10 or 36 Gy. In cases of classic CNV, low-dose irradiation with 10 Gy postponed severe visual loss by a maximum of 18 months. A positive treatment effect was also observed in cases irradiated with 36 Gy; however, a 25% incidence of radiation retinopathy seems unacceptable.