[Radiotherapy of macular lesions in age-related macular degeneration (AMD): initial results of a study inducted in Lyon, France].

PURPOSE

To evaluate irradiation effects on functional signs and choroidal neovascular lesions in age-related macular degeneration (AMD) that does not respond to laser therapy.

MATERIALS AND METHODS

Since 1994, 250 consecutive AMD patients were treated by two radiotherapy teams for subfoveal neovascular lesions. At the end of September 1996, 52 patients were evaluable with a 1-year follow-up. Group 1 (Département de Radiothérapie Oncologie, Centre Hospitalo-Universitaire Lyon Sud) included 26 patients who were treated with a lateral beam of 6 MV photons. The irradiation doses were 20 Gy in five fractions for small lesions and 28.8 Gy in eight fractions for larger lesions. Group 2 (Centre Oncologie Radiothérapie Saint-Jean) was composed of 26 patients treated with a mini-beam of 25 MV photons via lateral arc-therapy. Beam diameters (14 and 18 mm) were adapted to the lesion size. The total dose was 16 Gy in four fractions or 20 Gy in five fractions.

RESULTS

Functional and anatomical results were assessed at 3, 6, 9 months and 1 year after radiation therapy. Stable visual acuity was observed in 44% (23/52) of the patients and visual acuity was improved in 35% (18/52) of the patients at 6 months. Good functional results reached 79% (41/52) at 6 months and 74% (17/23) at 12 months. A significant decrease (> 10%) of the membrane was present in 46% (16/52) of the cases at 6 months and in 65% (15/23) of the cases at 12 months. There was no statistical difference between the two groups and dose levels. All severe complications (1 cataract, 3 dilated choridal vessels, and 2 papillitis) occurred in group 1.

CONCLUSION

Though it is too early to conclude on the best dose level, radiotherapy of subfoveal neovascular lesions of AMD that cannot be treated via laser therapy provides encouraging results. The technique used must be very precise to adequately irradiate the fovea and spare surrounding sensitive areas. Further studies and trials involving patients' randomization are necessary to confirm these preliminary results.