Palladium-103 plaque radiation therapy for macular degeneration: results of a 7 year study

Abstract

Aim: To report 7 year results of ophthalmic plaque radiotherapy for exudative macular degeneration. Methods: In a phase I clinical trial, 30 patients (31 eyes) were treated with ophthalmic plaque irradiation for subfoveal exudative macular degeneration. Radiation was delivered to a mean 2 mm from the inner sclera (range 1.2-2.4) prescription point calculated along the central axis of the plaque. The mean prescription dose was 17.62 Gy (range 12.5-24) delivered over 34 hours (range 18-65). Early Treatment Diabetic Retinopathy Study (ETDRS) type standardised visual acuity determinations, ophthalmic examinations, and angiography were performed before and after treatment. Clinical evaluations were performed in a non-randomised and unmasked fashion. Results: At 33.3 months (range 3-4), 17 of 31 (55%) eyes had lost 3 or more lines of vision on the ETDRS chart, five (16%) had improved 3 or more lines, and the remaining nine (29%) were within 2 lines of their pretreatment visual acuity measurement. Overall, 45% of patients were within or improved more than 2 lines of their initial visual acuity. Five eyes developed macular scars, eight developed subsequent neovascularisation or haemorrhage, and three progressed through therapy. Two patients were lost to follow up. The most common finding of patients followed for 6 or more months (n = 18 of 29 (62%)) was regression or stabilisation of the exudative process. No radiation retinopathy, optic neuropathy, or cataracts could be attributed to irradiation. Conclusion: Ophthalmic plaque radiation can be used to treat exudative macular degeneration. At the dose and dose rates employed, most patients experienced decreased exudation or stabilisation of their maculas. No sight limiting radiation complications were noted during 7 year follow up. Owing to the variable natural course of this disease, a prospective randomised clinical trial should be performed to evaluate the efficacy of plaque radiation therapy for exudative macular degeneration.

Gamma Knife Radiosurgery in the Treatment of Choroidal Neovascularization (Wet-Type Macular Degeneration)

“…Flaxel et al [17] treated patients with CNV with either 8 or 14 cobalt gray equivalents of protons and found that 14 cobalt gray equivalents seemed to inhibit the growth of CNV and stabilize VA, but that it lead to a high incidence of radiation retinopathy (44%). Plaque-based brachytherapy has been employed with mixed results (only short-term benefit in 1 study, with 45% long-term stabilization of VA in another) [18,19] .…”

Stellungnahme der Retinologischen Gesellschaft, der Deutschen Ophthalmologischen Gesellschaft und des Berufsverbands der Augenärzte Deutschlands zur Strahlentherapie bei neovaskulärer altersabhängiger Makuladegeneration

“…Studien zur primären episkleralen Brachytherapie bei AMD sind mit StrontiumApplikatoren ( 90 Sr/ 90 Y) [17,18] und Palladium-Applikatoren ( 103 Pa) [9,10] durchgeführt worden; 106 Ru/ 106 Rh-Applikatoren sind vereinzelt eigesetzt worden, ohne dass daraus eindeutige Daten abzuleiten wären [29].…”

“…Die von Finger al. publizierten Langzeitergebnisse nach Brachytherapie mit einem 103 Pa Applikator (10-122 mm breit; mittlere Dosis im Zielvolumen 17,62 Gray) konnten zeigen, dass es nach Brachytherapie zu einer deutlichen Rückbildung exsudativer Veränderun-gen kommt; ein Vorteil in Bezug auf eine bessere Funktion konnte allerdings nicht nachgewiesen werden [10].…”

Epimacular brachytherapy — old ghost or new age?

“…103 Pa is a (bitte griechisches gamma einsetzen)-emitter with a photon energy of 21 kV (compared to 28 kV for 125 I) with a lower tissue penetration compared to 125 I. Long-term results with a 103 Pa plaque were able to demonstrate a reduction of the exudation but no improvement in function [8]. 90 Sr is a β-emitter with a decay energy of 0.55 MeV and a half life of 27.78 years that decays to 90 Y with a decay energy of 2.27 MeV.…”

“…Brachytherapy can be applied using either episcleral [8,9] or epiretinal applicators via a pars plana approach [10].…”