RADIATION-THERAPY FOR OCULAR CHOROIDAL NEOVASCULARIZATION (PHASE I IISTUDY) - PRELIMINARY-REPORT/

Purpose/Objective: Choroidal neovascularization (CNV) is a major cause of severe loss of visual acuity in some ocular diseases such as age-r elated macular degeneration (ARMD) and angioid streaks. Laser photocoa gulation has been used to treat patients with subfoveal neovascular le sions with well-demarcated boundaries. However, the treatment method i s usually associated with a large decrease in visual acuity. Therefore , indications for this treatment are very limited. Recently, some inve stigators reported the effect of low dose irradiation on the subretina l neovascular membranes in CNV. We conducted a Phase I/II study to det ermine the toxicity and efficacy of external photon beam radiotherapy in patients,vith CNV. Methods and Materials: Between April, 1994 and J uly, 1995, 36 patients with choroidal neovascularization (34 with ARMD and 2 with angloid streaks) were treated with radiation therapy. Trea tment planning was performed using a CT simulator that enables real-ti me treatment planning from multiple CT slices. The clinical target vol ume that included the macula and optic disc received a dose of 10 Gy/5 fractions/1 week (first 18 eyes) or 20 Gy/10 fractions/2 weeks (last 18 eyes). All eyes were irradiated,vith a single lateral 6 MV photon b eam, angled 10 degrees posteriorly to exclude the ipsilateral lens and the contralateral eye from the radiation field. The ipsilateral lens was irradiated with less than 10% of the total reference dose. The fie ld size averaged 3.0 x 2.5 cm. Records of the 17 eyes with CNV referre d to our hospital in 1993, which satisfied the eligibility criteria fo r this study, were retrospectively analyzed for comparison. Results: T here was no significant acute morbidity. All patients were followed re gularly by both ophthalmologists and radiation oncologists. Cataract f ormation after 1 year of the treatment was observed in one patient who had received a dose of 20 Gy. One patient who had received 20 Gy comp lained of transient dry-eye sensation 2 months after treatment, but th is had disappeared spontaneously by the fourth month. The subjective s ymptoms, visual acuity, and size of the neovascular membrane were eval uated at 6 and 12 months after treatment in each patient. In the group of patients irradiated with 10 Gy and with 20 Gy, respectively, subje ctive symptoms improved in live and seven eyes, did not change in seve n and four eyes, and deteriorated in six and six eyes at 12 months. Al though visual acuity was significantly decreased in the control group, the patients in both irradiated groups did not show such a decrease i n visual acuity. The size of the neovascular membrane in the control g roup progressed significantly. However, the patients in the 20 Gy grou p showed significant regression of the membrane, although those in the 10 Gy group showed no significant change in size. Conclusion: This Ph ase I/II study including a dose escalation study showed that radiation therapy seems to be useful for CNV. The dose of 20 Gy in 10 fractions was more useful in treating neovascular membranes than the dose of 10 Gy in five fractions. These results have encouraged us to start a mul ticenter randomized prospective study of the treatment of CNV with rad iation therapy.; (C) 1997 Elsevier Science Inc.