Macular Degeneration: Munzenrider JE

Zambarakji HJ, Lane AM, Ezra E, Gauthier D, Goitein M, Adams JA, Munzenrider JE, Miller JW, Gragoudas ES. · Retina Service, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA. · Ophthalmology. · Pubmed #16935343 No free full text.

Abstract: OBJECTIVE: To evaluate safety and visual outcomes after proton therapy for subfoveal neovascular age-related macular degeneration (AMD). DESIGN: Randomized dose-ranging clinical trial. PARTICIPANTS: One hundred sixty-six patients with angiographic evidence of classic choroidal neovascularization resulting from AMD and best-corrected visual acuity of 20/320 or better. METHODS: Patients were assigned randomly (1:1) to receive 16-cobalt gray equivalent (CGE) or 24-CGE proton radiation in 2 equal fractions. Visual acuity was measured using standardized protocol refraction. Complete ophthalmological examinations, color fundus photography, and fluorescein angiography were performed before and 3, 6, 12, 18, and 24 months after treatment. MAIN OUTCOME MEASURE: Proportion of eyes losing 3 or more lines of vision from baseline. Kaplan-Meier statistics were used to compare cumulative rates of vision loss between the 2 treatment groups. RESULTS: At 12 months after treatment, 36 eyes (42%) and 27 eyes (35%) lost 3 or more lines of vision in the 16-CGE and 24-CGE groups, respectively. Rates increased to 62% in the 16-CGE group and 53% in the 24-CGE group by 24 months after treatment (P = 0.40). Radiation complications developed in 15.7% of patients receiving 16 CGE and 14.8% of patients receiving 24 CGE. CONCLUSIONS: No significant differences in rates of visual loss were found between the 2 dose groups. Proton radiation may be useful as an adjuvant therapy or as an alternative for patients who decline or are not appropriate for approved therapies.

Adams JA, Paiva KL, Munzenrider JE, Miller JW, Gragoudas ES. · Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA. · Med Dosim. · Pubmed #10643731 No free full text.

Abstract: Age-related macular degeneration is the leading cause of blindness in developing countries. Irradiating the exudative form, in which a choroidal neovascular membrane develops in the subfoveal area, is presently a treatment under investigation. In 1995, Massachusetts General Hospital, collaborating with Massachusetts Eye and Ear Infirmary, initiated a protocol to treat SCNV membranes using the proton beam at the Harvard Cyclotron Laboratory and the EYEPLAN program with a light-field setup. EYEPLAN requires the axial eye length, membrane dimensions, and manipulation of the eye to include a 4.0-mm radial margin around the membrane so that the aperture margin (50% isodose line on the posterior retina) abuts the inferior aspect of the limbus. Review of 100 individually prepared plans showed that 95% of the fabricated apertures were circular (aspect ratio < 1.095) with diameters 9.5 to 15.0 mm. This information was used to develop an automated standard plan. Thirty-nine plans were developed for axial lengths ranging from 21.0 to 25.0 mm and membrane sizes from 1.5 to 6.75 mm in the usual way as the reviewed ones. Circular targets were outlined centered on the fovea. Distal and proximal 90% ranges (modulation) to the target, and doses to macula, optic disc, lens, ciliary body, retina, and globe were calculated. An automated standard plan requiring the same input data, but avoiding the need for individual plans, was developed. The program outputs the aperture diameter, fixation angle for the light-field setup, range and modulation, and calculates dose to the macula and optic nerve and percentage of retina receiving > or = 50% and > or = 90% of the prescribed dose. Individual plans require approximately 1.5 hours; the standard plan, 5 minutes. The standard plan could have treated 86% of the reviewed plans. The automated plan provides accurate and efficient treatment parameters for the majority of patients.

Munzenrider JE. · Department of Radiation Oncology, Massachusetts General Hospital, Harvard University Medical School, Boston, USA. · Strahlenther Onkol. · Pubmed #10394402 No free full text.

Abstract: Charged particle beams are ideal for treating intra-ocular lesions, since they can be made to deposit their dose in the target, while significantly limiting dose received by non-involved ocular and orbital structures. Proton beam treatment of large numbers of uveal melanoma patients consistently achieves local control rates in excess of 95%, and eye retention rates of approximately 90%. Visual preservation is related to initial visual acuity, tumor size and location, and dose received by the macula, disc, and lens. The probability of distant metastasis is increased by larger tumor diameter, more anterior tumor location, and older patient age. Proton therapy is also effective treatment for patients with ocular angiomas, hemangiomas, metastatic tumors, and retinoblastomas, and may be beneficial for patients with exudative ("wet") age-related macular degeneration.