Radiation therapy for subfoveal choroidal neovascular membranes in age-related macular degeneration. A pilot study

Surgical Removal of Subretinal Neovascular Membranes

Since 1991 we have been gaining experience in the surgical removal of submacular subretinal membranes in patients with presumed ocular histoplasmosis syndrome (POHS), idiopathic subretinal neovascularisation, myopia and age-related macular degeneration (AMD). Seventeen patients were operated between 1991 and 1993. Significant improvement of vision was achieved in 4 out of 5 patients with POHS, 3 out of 5 with idiopathic neovascularisation, 2 out of 4 with myopia but none of 3 patients with AMD. The results suggest that subretinal neovascularisation can be successfully removed in POHS and in some forms of idiopathic neovascularisation and myopia but probably not in AMD.

Successful treatment of choroidal neovascular membrane in retinitis pigmentosa with intravitreal bevacizumab

We report a rare association of choroidal neovascularization (CNV) with retinitis pigmentosa and note its resolution by intravitreal injection of the anti-vascular endothelial growth factor (VEGF), bevacizumab. A classic choroidal neovascular membrane was seen in the right eye (RE) of a patient with sector retinitis pigmentosa. Bevacizumab 1.25 mg in 0.05 ml was injected intravitreally. The choroidal neovascular membrane was seen to regress following this single intravitreal bevacizumab injection with formation of a scar. CNV has very rarely been seen in association with retinitis pigmentosa. Anti-VEGF drugs have been shown to have a beneficial role in CNV with other causes; in this case their effectiveness in CNV associated with retinal dystrophies, for example retinitis pigmentosa, has been demonstrated.

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

We evaluated retrospectively our institutional experience in the treatment of macular degeneration with gamma knife radiosurgery (GKR). Treatment was delivered in a single shot of 12 Gy. Seven patients were treated between March of 1999 and May of 2000. The median duration of follow-up was 2.2 years. The majority of patients maintained stable visual acuity after treatment. Our series indicates that GKR may be useful as a salvage treatment for patients who have failed or are ineligible for other treatments for their macular degeneration. Further studies are needed to better define the role of GKR in the treatment of macular degeneration.

Results of radiotherapy of subfoveal neovascularization with 16 and 20 Gy

PURPOSE

In a nonrandomized, prospective study the efficacy of radiotherapy with 16 and 20 Gray (Gy) for subfoveal neovascularization in age-related macular degeneration (ARMD) was analysed.

MATERIAL AND METHODS

From 1996 to 1998, 63 eyes were irradiated with 16 Gy and 38 eyes with 20 Gy for exudative ARMD. A total of 12 eyes had classic ARMD, 89 eyes occult ARMD, median baseline visual acuity (VA) was 6/30 (range: 3/60-6/9.5), median age was 78 years. Risk factors (type of ARMD, baseline VA) were evenly distributed in both groups. Median follow-up was 1.3 years (range: 4 months-4.7 years). VA of +/-1 line or better and unchanged size and activity of the membrane in fluorescein angiography were defined as stable. Actuarial methods were used.

RESULTS

Median loss of VA was -3 lines (range: -14 to +5), neovascularization remained unchanged or decreased in size and activity in 35 eyes. At 18 months, the probability of stabilized VA was 0.4 (95% confidence interval (CI): 0.3-0.5), at 24 months 0.3 (95% CI: 0.2-0.4). Radiation dose, type of ARMD or baseline VA had no significant impact on outcome of VA and membrane size and activity (P>0.05). Side effects were mild and transient increased tearing.

CONCLUSION

In this study, the results after radiotherapy were comparable to the natural course of the disease. An impact of radiation dose (16 vs 20 Gy) on stabilizing visual acuity and subfoveal neovascularization could not be shown. The results of studies on dose escalation using very small fields and high radiation doses should be awaited.

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

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.

Review Article. New treatments in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in individuals 50 years and older in the developed world. Choroidal neovascularization (CNV) in exudative AMD is responsible for the majority of severe vision loss. Until recently, laser photocoagulation was the only well-established and widely accepted treatment for CNV. However, it is beneficial only for a small subset of patients, has a high rate of CNV persistence and recurrence and results in iatrogenic, collateral damage to the overlying retina. These issues make it difficult to recommend in the case of subfoveal lesions. Consequently, numerous experimental therapeutic interventions are under investigation with the common objective of destroying the CNV but leaving the foveal neurosensory retina intact. Treatment modalities can be grouped into five major categories: photodynamic therapy; radiotherapy; transpupillary thermotherapy; anti-angiogenic and angiostatic agents; and surgical intervention. The present review aims to explain the rationale behind these new treatments, analyse the evidence for their safety and efficacy, determine their stage of development and indicate in which patients they are potentially useful.

Clinicopathological correlation of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration

PURPOSE

To analyze the histopathology of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration.

METHODS

A retrospective non-case-matched comparative histopathologic study. The histoarchitecture of nine surgically removed subretinal specimens from nine patients that had undergone external beam radiotherapy for exudative age-related macular degeneration was studied. Seven patients had received 20 Gy in 10 fractions and two 15 Gy in 5 fractions with an average time interval between radiotherapy and surgical extraction of 14 months (range 3-28). A consecutive series of classic, mixed and occult choroidal neovascular membranes served as controls.

RESULTS

Clinical findings. Radiation-associated choroidal neovasculopathy was angiographically suspected in four patients: a coarse net of vessels on fluorescein angiography developing at the border of previously irradiated choroidal neovascularization was observed in three patients; blebs at the margin of a plaque on indocyanine green angiography were observed in two patients. Pathological findings. Diffuse drusen as well as intra-Bruch's fibrovascular tissue was found in all irradiated specimens. In four specimens an edematous vascularized layer was seen between diffuse drusen and normal-appearing intra-Bruch's fibrovascular tissue. This lesion was not found in the control specimens. A particular correlation for the bleb lesion was not recognized.

CONCLUSION

The appearance of an edematous subretinal pigment epithelial vascularized layer between diffuse drusen and normal-appearing fibrovascular tissue in four of nine irradiated membranes may be secondary to previous irradiation. It may correlate with the unusual exudative manifestations observed after external beam radiotherapy.

Magnetic resonance imaging analysis of anterior and posterior eye segment displacement during ocular gaze shifts

PURPOSE

To determine the relationship between movements of the posterior and anterior eye segments during arbitrary gaze shifts and to obtain information for monitoring fixation during radiotherapy for ocular diseases.

METHODS

We examined eye movements of ten emmetropic volunteers in a 1.5 T magnetic resonance system. Using a T2-weighted ultrafast turbo-spin echo sequence (UTSE), the eyes were examined within 21 seconds. Sagittal and transversal eye slices were obtained in five passages in five gaze directions (straight ahead, 15 degrees above, 15 degrees below, 15 degrees right and 15 degrees left of the primary position). Displacement of the posterior eye segment was analyzed in relation to the movement of the anterior segment in all directions.

RESULTS

The relationship between the movements of the anterior and posterior eye segment was 1:0.8 (+/- 0.06 SD) during horizontal gaze shifts and 1:1.16 (+/- 0.11 SD) during vertical gaze shifts.

CONCLUSIONS

Magnetic resonance imaging showed that the relationship between anterior and posterior eye segments was different during horizontal and vertical eye movements, indicating the presence of more than one center of rotation. Compared to the anterior eye segment, there was less displacement of the posterior eye segment during horizontal eye movements and more displacement during vertical eye movements.

Age-related macular degeneration: epidemiology and optimal treatment

Age-related macular degeneration (AMD) is a common macular disease affecting elderly people in the Western world. It is characterised by the appearance of drusen in the macula, accompanied by choroidal neovascularisation (CNV) or geographic atrophy. The disease is more common in Caucasian individuals than in pigmented races. In predominantly Caucasian populations, the age-standardised prevalence of AMD in at least one eye is 7760 cases per million. The age-standardised cumulated 1-year incidence of AMD in at least one eye is 1051 cases per million individuals. AMD is the most important single cause of blindness among Caucasian individuals in developed countries. Blindness resulting from AMD rarely occurs before age 70, and most cases occur after age 80. The age-standardised 1-year incidence of legal blindness resulting from AMD is 212 cases per million. Two-thirds of AMD cases have CNV (exudative cases); the remainder has only geographic atrophy. In cross-sectional population-based studies about 45% of eyes with AMD have visual acuity reduced to 20/200 or worse. This is true both for exudative AMD and pure geographic atrophy. Age and genetic predisposition are known risk factors for AMD. Smoking is probably also a risk factor. Preventive strategies using macular laser photocoagulation are under investigation, but their efficacy in preventing visual loss is as yet unproven. There is no treatment with proven efficacy for geographic atrophy. Optimal treatment for exudative AMD requires a fluorescein angiographic study and a physician capable of interpreting it. For CNV not involving the foveal centre, the only evidence-based treatment is laser photocoagulation. For AMD cases with subfoveal CNV, good visual acuity, and predominantly classic fluorescence pattern on fluorescein angiography, photodynamic therapy with verteporfin is the treatment of choice. Photodynamic therapy is also effective in eyes with pure occult CNV and evidence of recent disease progression. For new subfoveal CNV with poor vision and recurrent CNV, laser photocoagulation can be considered.

Radiotherapy in age-related macula degeneration

PURPOSE

To ascertain the benefit from radiotherapy in age-related macula degeneration in a single-arm longitudinal study.

METHODS AND MATERIALS

From 1997 to 1998, 39 patients with occult and 33 patients with classic choroidal neovascularization (CNV) were irradiated with 16 Gy. Fluorescein angiography and measurements of visual acuity were performed before and 3, 6, and 12 months after irradiation.

RESULTS

Complete follow-up data for 1 year were available from 69 patients. The mean patient age was 72 years (range 49-92). Vision decreased in 43, was stable in 18, and improved in 8 cases. The mean vision deteriorated significantly (p = 0.02, Wilcoxon test), particularly within the first 3 months. Patients with occult CNV did significantly better than did those with classic CNV (p = 0.03). The proportion of patients retaining vision > or = 0.2 fell from 65% to 42% (p <0.01), for classic and occult CNV from 50% to 23%, and for occult CNV from 77% to 56% (p < 0.02), respectively. CNV size increased in 30 patients and was stable in 38. Neither age (p = 0.17) nor gender (p = 0.21, chi-square test) influenced prognosis. Four patients reported transitional complaints.

CONCLUSION

Low-dose fractionated radiotherapy with 16 Gy is well tolerated. However, vision and reading ability were not preserved in most patients.

Gamma knife treatment of subfoveal, classic neovascularization in age-related macular degeneration: a pilot study

Object. Age-related macular degeneration (AMD) is the leading cause of severe vision loss in people older than age 65 years in the western world. The visual acuity loss usually results from the ingrowth of new vessels from the choroid capillaries, so called choroidal neovascularization (CNV). The aim of this pilot study was to investigate the effect of a single-fraction gamma knife radiosurgery (GKS) on visual acuity and the growth pattern of CNV in patients with AMD.

Methods. Ten patients with a mean age of 75 years and with a subfoveal, classic CNV due to AMD were enrolled in this study. All patients were treated with GKS in one fraction with a prescription dose of 10 Gy. The treatment target was the CNV located in the macula. Computerized tomography scans of the globe were obtained.

After a follow up of 1 year visual acuity was stable in six patients and decreased in four. The size of the CNV could be stabilized in four patients, and in six an enlargement of these neovascular complexes was shown. No side effects, such as cataract formation, development of radiation-induced retinopathy, or optic neuropathy, have been observed so far.

Conclusions. Gamma knife radiosurgery seemed to have a beneficial effect on visual acuity in patients with AMD, but it failed to control growth of CNV in six patients. A longer follow up, a larger study population, and a randomized and controlled study are necessary for a final conclusion.

Age-related macular degeneration: long-term results of radiotherapy for subfoveal neovascular membranes

PURPOSE

To study results of 2-year follow-up of radiotherapy for subfoveal choroidal neovascular membrane associated with age-related macular degeneration.

METHODS

In a randomized prospective clinical study, 101 patients received a low-dose radiotherapy or no treatment. In the treatment group, subfoveal choroidal neovascular membranes were treated with 20 Gy of 6-MV photons to the macula of the affected eye.

RESULTS

The overall complete follow-up rate was 84.2% (85/101). No measurable treatment-related morbidity was seen during or after treatment. Mean changes in log of minimal angle of resolution (logMAR) of visual acuity and area of choroidal neovascular membrane for 2-year follow-up were +0.226 +/- 0.373 and 143.5 +/- 53.1% in the treatment group, and +0.563 +/- 0.370 and 190. 3 +/- 81.4% in the control group; a significant difference was found (P <.0001; P =.0008). In patients with smaller choroidal neovascular membrane (</=1.5 mm(2)) or better visual acuity (>/=60/200) at baseline, the treatment group showed a significantly smaller increase in area of choroidal neovascular membrane and a significantly smaller decrease in LogMAR visual acuity for 2 years, whereas there was no significant difference in patients with larger choroidal neovascular membrane (>1.5 mm(2)) or poorer visual acuity (<60/200).

CONCLUSIONS

Radiotherapy appeared to have a favorable treatment effect in eyes with subfoveal neovascular membrane associated with AMD. Favorable factors for radiotherapy were a smaller area of choroidal neovascular membrane and better visual acuity.

Macular translocation: histopathologic findings in swine eyes

PURPOSE

Macular translocation has been proposed as an alternative technique in the treatment of some cases of choroidal neovascularization. The purpose of the paper is to report the histopathologic findings in the retina of swine eyes undergone macular translocation.

METHODS

Ten eyes of ten Yucatan pigs underwent posterior pars plana vitrectomy and scleral imbrication to achieve macular translocation. Mattress sutures were preplaced at the equator of the eyes. After a pars plana vitrectomy, balanced saline solution was injected under the temporal retina to produce a retinal detachment. Scleral imbrication was achieved by tightening the mattress sutures. An air-fluid exchange was performed and the eye was filled with sulfur hexafluoride 18%. The eyes were enucleated 2, 4, 8 and 12 weeks after surgery and analyzed under light and electron microscopy.

RESULTS

Macular translocation was achieved in all cases. The major findings consist of a minimal decrease in the number of photoreceptors outer segments; also a change in the morphology was noted. This included some degree of loss of vertical alignment and an increase in the interphotoreceptor space. There was a recovery in the morphology of the photoreceptors over time.

CONCLUSIONS

Minimal changes in the photoreceptors and retinal pigment epithelium are observed when macular translocation is performed with recovery of these changes over time. Scleral imbrication is an effective technique to achieve translocation of the fovea.

Radiotherapy for subfoveal neovascularisation associated with pathological myopia: a pilot study

BACKGROUND/AIM

Limited treatments are available for this disease process. A pilot study was performed to determine the toxicity and efficacy of external beam radiotherapy for subfoveal neovascular membranes and subretinal haemorrhage associated with pathological myopia.

METHODS

A randomised, prospective study was carried out on 39 patients with subfoveal neovascularisation associated with high myopia. 20 patients underwent radiotherapy and the remaining 19 were observed as a randomised comparison group. All patients were followed up for at least 24 months. Subfoveal choroidal neovascular membranes (CNVMs) were treated with a single lateral 6 MV photon beam to a dose of 10 Gy in five fractions over 5-7 days. Post-treatment measurements included corrected visual acuity, area of CNVM, and occurrence of radiotherapy related complications, and adverse reactions. To assess changes of area of CNVM, the initial (pretreatment) size of the CNVM was set to 100%, and all post-treatment measurements were normalised relative to the initial size.

RESULTS

No significant acute morbidity was noted. There was no significant difference in age, sex, refractive error, visual acuity, and area of CNVM at baseline between the treatment group and control group. The mean change of the size of the CNVM for 2 years was 155% (SD 156%) in the treatment group and 249% (124%) in the control group. The increase in the size of CNVM in the treatment group was significantly smaller than that in the control group (p = 0.0452). In the treated eyes, the visual acuity before and 1 and 2 years after radiotherapy were 0.111 (22.2/200), 0.091 (18.2/200), and 0.086 (19.2/200), respectively. In the control eyes, visual acuity before and 1 and 2 years after the start of the follow up were 0.141 (34.2/200), 0.089 (17.8/200), and 0.063 (12.6/200). The patients in the treatment group showed no significant change for 2 years, and those in the control group showed a significant decrease in the visual acuity (p = 0.0033). The changes of logMAR of visual acuity for 2 years after the start of the follow up were +0.019 (0. 443) in the treatment group and +0.347 (0.374) in the control group. There was a statistically significant difference between them (p = 0. 0173). Multiple regression analysis on the treatment group showed that the most significant predictive variable for the visual acuity 2 years after the treatment was the combination of pretreatment visual acuity and refractive error.

CONCLUSIONS

Radiotherapy appeared to have a favourable treatment effect in eyes with subfoveal neovascular membranes and haemorrhage associated with pathological myopia. Further investigation is needed to evaluate the efficacy of radiotherapy for subfoveal neovascularisation associated with pathological myopia.

Radiotherapy for age related macular degeneration causes transient lens transparency changes

AIM

Evaluation of potential side effects of photon radiotherapy on the transparency of the lens.

METHODS

The anterior segments of 14 phakic eyes from patients suffering from subfoveal neovascularisation as a result of age related macular degeneration (AMD) were documented by Scheimpflug photography (Topcon SL-45, Kodak Tmax 400) before the start of radiotherapy as well as 6 and 12 months afterwards. All negatives were evaluated by microdensitometry, and peak heights for distinct layers of the lens were used for statistical comparison. External beam radiotherapy (6 MeV photons) consisted of a total dose of 20 Gy, delivered as 10 fractions of 2 Gy.

RESULTS

Six and 12 months following irradiation statistical comparison of the ratios in density change of lenses from irradiated versus non-irradiated fellow eyes revealed statistically significant (p</=0.05) loss of transparency of layers 5 and 7 of the nuclear region. In layer 1 (capsuloepithelial complex) the changes were close to significance. At the 12 month examination, however, all of these significant changes had disappeared.

CONCLUSION

Six months following radiotherapy for AMD, both the anterior capsuloepithelial region and the nuclear layers showed precataractous changes. As most of these significant differences had disappeared after 12 months, it is obvious that these findings reflect acute radiation damage to the lens epithelial cells and an ionising effect on the proteins of the lens nucleus. Long term studies will have to be carried out to demonstrate whether or not this acute radiation damage, which is expressed as a transient increase in light scattering of some layers of the lens, actually does lead to permanent transparency changes, thus reflecting radiation cataractogenesis, and if so, after what time interval and to what extent cataract occurs.

Proton beam irradiation of subfoveal choroidal neovascularisation in age-related macular degeneration

PURPOSE

To assess the safety and potential toxicity of proton beam radiation in the treatment of subfoveal choroidal neovascular membrane (CNVM) due to age-related manner degeneration (ARMD) in a prospective, non-randomised study.

METHODS

Forty-eight eyes of 46 consecutive patients with subfoveal CNVM due to ARMD, not amenable to laser photocoagulation, were treated prospectively with a single proton beam exposure. Two dose regimens were evaluated: 8 CGE (Cobalt Gray Equivalent) and 14 CGE. Patients were followed for an average of 22.1 months after proton beam treatment.

RESULTS

At the 12 month follow-up, 44% of eyes in the 8 CGE group and 75% of the eyes in the 14 CGE group had stabilized or improved visual acuity. Complex size in the 8 CGE group as measured on standard fluorescein angiography (FA), decreased or had no change initially but showed less effect over time, while the eyes treated with 14 CGE maintained decreased leakage over the follow-up period of 12 months. However, 11 eyes in the 14 CGE group experienced radiation retinopathy, with the onset between 3 and 30 months. Seven of these 11 eyes have demonstrated some visual loss but only 1 eye developed severe visual loss at 15 months after proton treatment.

CONCLUSIONS

To date, 14 CGE has suggested a favourable influence on visual function and growth inhibition of CNVM. Proton beam irradiation appears to inhibit CNVM growth. The 14 CGE dose regimen appears to have a longer effect of CNVM growth than does 8 CGE, with overall stabilisation of visual function and growth inhibition. Radiation retinopathy has developed over time, but severe visual loss has been limited. On the basis of the incidence of radiation retinopathy, adjustments in the total radiation dosage and/or fractionation of the dosage should be considered.

Treatment of age-related macular degeneration

Age-related macular degeneration (AMD), while rapidly becoming more prevalent due to an aging population, is still poorly understood and treatment modalities are limited. Fortunately, advances are being made in the treatment of AMD that may greatly alter the outcome of this debilitating disease. Treatments for both wet and dry AMD are reviewed.

A prospective, randomized, double-masked trial on radiation therapy for neovascular age-related macular degeneration (RAD Study). Radiation Therapy for Age-related Macular Degeneration

OBJECTIVE

To determine the efficacy of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD).

DESIGN

Multicenter, parallel, randomized, double-masked clinical trial performed at nine ophthalmic and radiotherapeutic centers.

PARTICIPANTS

Two hundred five patients were randomly assigned either to treatment with 8 fractions of 2 Gy external beam irradiation (n = 101) or to control with 8 fractions of 0 Gy (sham treatment, n = 104). Both patients and ophthalmologists were masked with regard to applied treatment. Patients with subfoveal classic or occult CNV, visual acuity of 20/320 or greater on the Early Treatment Diabetic Retinopathy Study chart, lesion size of 6 disc areas or less, history of visual symptoms of 6 months or less, and absence of foveal hemorrhage were recruited.

INTERVENTION

In the treatment group, external beam irradiation with 8 fractions of 2 Gy was performed, whereas in the control group, sham treatment with 8 fractions of 0 Gy was applied.

MAIN OUTCOME MEASURES

Primary outcome measure was the difference in visual acuity between baseline and after 1 year of follow-up.

RESULTS

One hundred eighty-three patients (89.3%) completed the 1-year follow-up. The mean reduction in visual acuity was 3.5 +/- 4.7 lines in 88 patients of the 8- x 2-Gy treatment group and 3.7 +/- 3.8 lines in 95 patients of the 8- x 0-Gy control group. This difference was not statistically significant (P = 0.53, Mann-Whitney U test). At 1 year, 51.1% of treated patients and 52.6% of control subjects lost three or more lines (P = 0.88). Visual acuity in the presence of classic CNV dropped by 3.7 +/- 4.4 lines in 33 patients of the treatment group versus 4.3 +/- 3.9 lines in 36 patients of the control group (P = 0.47). Visual acuity in 114 patients with occult CNV dropped by 3.4 +/- 4.9 in the treatment group (55 patients) versus 3.4 +/- 3.8 lines in the control group (59 patients) (P = 0.80).

CONCLUSIONS

In this randomized study, radiation therapy at a dose of 16 Gy applied in 8 fractions of 2 Gy provided no benefit as a treatment for subfoveal CNV secondary to ARMD at 1 year.

Long term results of radiotherapy for subfoveal choroidal neovascularisation in age related macular degeneration

BACKGROUND/AIMS

Radiotherapy has been proposed as an alternative treatment for patients with subfoveal choroidal neovascularisation (CNV) that is untreatable according to macular photocoagulation study guidelines. This prospective study was designed to evaluate whether radiotherapy may affect the functional and anatomical outcome in a large cohort of patients affected by subfoveal CNV, with a follow up period up to 24 months.

METHODS

212 patients (231 eyes) with newly diagnosed subfoveal CNV not amenable to laser therapy were included in this study. Two radiotherapy methods, the lateral beam technique (6 MV, 20 Gy in five fractions) and lateral arc therapy (25 MV, 16 to 20 Gy, in four or five fractions), were used. Comparisons of best corrected visual acuity (VA), fluorescein (FA) and indocyanine green (ICG) angiography, at inclusion and 6, 12, 18, and 24 months after radiotherapy were performed using univariate analysis.

RESULTS

A VA improvement of two or more lines was observed in 34% at 12 months, 31% at 18 months, and 32% of the eyes at 24 months. Paired comparisons of CNV areas in FA and ICG showed no significant change between baseline and each visit. However, 12 and 18 months after treatment, 47% of the eyes showed a decrease of 10% or more in CNV size both in ICG and FA. Radiation side effects included radiation retinopathy (eight eyes), optic neuropathy (four eyes), choroidal vasculopathy (five eyes), and branch retinal vein occlusion (three eyes).

CONCLUSION

Compared with the natural course of subfoveal CNV, the results of this prospective study suggest that radiotherapy could stabilise visual and anatomical outcome in selected cases.

Radiotherapy for isolated occult subfoveal neovascularisation in age related macular degeneration: a pilot study

BACKGROUND/AIMS

Teletherapy has been proposed as a possible treatment for choroidal neovascular membranes (CNV), secondary to age related macular degeneration (AMD) not amenable to laser photocoagulation. The aim of this prospective study has been to investigate the effect of teletherapy on isolated occult choroidal neovascular membranes of subfoveal location.

METHODS

28 AMD patients presenting with retrofoveal isolated occult CNV demonstrated by fluorescein angiography were treated by external beam radiation. A complete ophthalmological examination, fluorescein angiography, and indocyanine green angiography (ICG) were performed within 15 days before treatment and repeated at follow up. A total dose of 16 Gy was applied in four sessions of 4 Gy using a 4 MeV photon beam. Follow up ranged from 6 to 9 months (mean follow up 6.4 months).

RESULTS

Visual acuity was found to be stable in 68% of the cases. The decrease in visual acuity was of 3-6 lines in 18% and of more than 6 lines in 10% of the eyes at last examination. On fluorescein angiography the size of the lesion area was found to be stable in 67%, decreased in 13%, and increased in 20% of the cases. On ICG angiography the size of the CNV was stable in 93% and increased in 7% of the cases. All the eyes experiencing a visual acuity decrease showed either no change or an increase in size of the membrane on fluorescein angiography and/or on ICG.

CONCLUSION

According to this study with strict inclusion criteria, external beam radiotherapy seems to have a beneficial effect on the evolution of isolated occult subfoveal CNV.

Treatment of macular degeneration with proton beams

Subfoveal neovascular membranes (SNVMs) are a leading cause of severe visual loss in the elderly in the United States. Previously, the only treatment that could halt progression of this disease was laser photocoagulation, which was, however, accompanied by immediate reduction in visual acuity. A single narrow proton beam was used to irradiate 45 patients to either 8 or 14 Cobalt Gray Equivalent. The alignment technique and dosimetry of these treatments are described. The proton beam direction, range, and modulation were planned with the assistance of an eye-specific planning program. A single anterior beam was used, with patients looking nasally toward a blinking fixation light at an angle of 30 degrees. Patients were aligned using a light field projected through a slit collimator. Patients' positions were monitored during treatment with a short-focal-length camera. Depth dose in a flat phantom was measured with a small-diameter parallel plate ionization chamber. Lateral profiles were measured at several depths with silver halide film. Each treatment session lasted 15 min, of which 1 min consisted of beam delivery. The proton beam stopped in the orbital cavity, delivering no primary proton dose to the brain. Dose to the center of the lens of the involved eye was less than 0.5% of the dose delivered to the macula. Treatments of SNVMs with proton beams require only a short visit to the hospital, little immobilization effort, and a minimal amount of treatment room and beam time. Compared to previous treatment trials using x-ray beams, the dose to nonocular tissues is reduced significantly.

Radiation therapy for age-related macular degeneration

Neovascular age-related macular degeneration is the most common cause of severe irreversible blindness in the Western world in people older than age 50. Laser photocoagulation is the only proven treatment for this disease; however, fewer than 20% of patients are eligible for this treatment because the majority of choroidal neovascularization membranes are not visible by ophthalmoscopy or angiography. In addition, many patients elect not to undergo this treatment because laser treatment of subfoveal neovascular membranes results in immediate and permanent central visual loss. Several treatments are under investigation, including external-beam radiation therapy. There are multiple publications of early trials using radiation therapy, but to date there is only one randomized published study. This article reviews these trials and summarizes the status of radiation therapy as a treatment for macular degeneration.

Radiation therapy in exudative age-related macular degeneration

It has been suggested that ionizing radiation at doses relatively safe to the optic nerve and retina exert an inhibitory and occlusive effect on the endothelial proliferation of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). The encouraging results of early studies in preservation or improvement of visual acuity and regression of the CNV gave rise to many clinical trials in different centers. Disparate radiation doses, dose fractions, type and rate of radiation administration have been used to determine the efficacy of radiotherapy in AMD. Conflicting treatment responses have been reported by different centers. Some studies provided evidence of beneficial treatment outcome in AMD, and others could not show any efficacy of ionizing radiation in the visual and morphological evolution of the disease. Data from the literature and our experience indicate that radiotherapy can be effective in regressing the leakage of the CNV in AMD. However, despite treatment visual deterioration continues and new CNV lesions develop. The observation of morphological progression in the disease process might be related to an unfavorable effect of radiation on the pathogenesis of AMD.

The use of confocal scanning laser tomography in the evaluation of retinal elevation in age-related macular degeneration

OBJECTIVE

To evaluate the feasibility of using confocal scanning laser tomography in the analysis of macular topography in patients with subfoveal choroidal neovascularization associated with age-related macular degeneration (AMD) and to analyze quantitatively the changes in topography after local strontium-plaque radiation therapy.

DESIGN

Prospective case series.

PARTICIPANTS

A total of 16 eyes with subfoveal choroidal neovascular membranes (CNVM) treated with strontium-90 (90Sr)-plaque radiation therapy and 16 fellow eyes of 16 patients were examined.

INTERVENTION

Confocal scanning laser analysis of macular surface topography before and after irradiation of the macula was performed.

MAIN OUTCOME MEASURES

Parameters describing the height and volume of the retinal elevation in the macula were measured.

RESULTS

The maximum height of the macular lesion at baseline was 0.25 mm (standard deviation [SD], 0.12 mm) in eyes showing regression of the CNVM during follow-up and 0.34 mm (SD, 0.19 mm) in eyes showing continued growth of the CNVM. During follow-up, a mean decrease in the maximum height of the macular lesion ranging from 0.03 to 0.10 mm occurred in eyes with regression of the CNVM, whereas the mean maximum height increased by 0.07 to 0.15 mm during follow-up visits in eyes with continued growth of the CNVM. All parameters describing the mean height and volume of the lesion also decreased significantly in patients showing angiographic regression, whereas they increased or remained unchanged in patients with continuous growth of the CNVM despite irradiation. The corresponding parameters also were higher in fellow eyes with untreated CNVM than in eyes without exudative AMD.

CONCLUSIONS

Confocal scanning laser tomography can be used to monitor the amount of the change in neurosensory detachment in AMD. The parameters obtained by confocal scanning laser tomography correlate with CNVM perfusion after 90Sr-plaque radiation therapy. This technology is a useful tool for objective evaluation of morphologic change after institution of new therapeutic methods for the treatment of AMD.

Ophthalmic plaque radiotherapy for age-related macular degeneration associated with subretinal neovascularization

PURPOSE

To evaluate ophthalmic plaque radiotherapy for the treatment of subretinal neovascularization associated with age-related macular degeneration.

METHODS

In a prospective phase I clinical trial, we treated 23 patients (23 eyes) with ophthalmic plaque radiotherapy for subfoveal exudative macular degeneration. Palladium 103 ophthalmic plaque brachytherapy was delivered to a retinal apex dose of 1,250 to 2,362 cGy (rad). Early Treatment Diabetic Retinopathy Study type visual acuity determinations, ophthalmic examinations, and angiography were performed before and after treatment. Clinical evaluations were performed in a nonrandomized and unmasked fashion.

RESULTS

Patients were followed up for a mean (+/-SD) of 19 +/- 10.7 months (range, 3 to 37 months). Six months after radiation therapy, three (16%) of 19 eyes had lost 3 or more lines of best-corrected visual acuity; 12 months after radiation therapy, four eyes (31% of 13 eyes), and 24 months after radiation therapy, only two (22% of nine eyes) lost 3 or more lines of visual acuity. No eye suffered sudden irreversible loss of central vision. No radiation retinopathy, optic neuropathy, or cataract could be attributed to radiotherapy within this follow-up period.

CONCLUSION

Ophthalmic plaque radiotherapy can be used to treat neovascular age-related macular degeneration. In contrast to external beam radiotherapy, ophthalmic plaque radiotherapy is a unilateral treatment, which allows a larger dose to be delivered to the macula with less irradiation of normal ocular structures. We have found no sight-limiting complications at the doses, dose rates, and follow-up evaluated in this study.

Indocyanine green guided laser photocoagulation in patients with occult choroidal neovascularisation

AIMS

To determine whether indocyanine green (ICG) guided laser photocoagulation of occult choroidal neovascularisations (OCNV) is beneficial for patients with occult choroidal neovascularisation secondary to age related macular degeneration (AMD).

METHODS

A prospective pilot study was performed in 21 eyes with OCNV secondary to AMD that could be identified extrafoveolarly or juxtafoveolarly in an early ICG angiographic study. Laser photocoagulation was applied to the neovascular membrane identified in the early ICG angiographic study.

RESULTS

Visual acuity ranged from 20/400 to 20/20 (logMAR 0.54 (SD 0.29) before and hand movements and 20/30 (logMAR 0.81 (0.69)) at the last follow up after laser photocoagulation. During the follow up (30 (13) months) vision improved in four eyes (two lines), in seven eyes the initial visual acuity could be stabilised (two lines), in five eyes vision dropped moderately (three to five lines), and in five eyes vision decreased severely (six or more lines). Recurrences (seven patients) or persistent CNV (six patients) was observed in 13 patients.

CONCLUSION

This preliminary study of ICG guided laser photocoagulation of occult extrafoveal and juxtafoveal choroidal neovascularisations suggests that this technique may improve the visual prognosis of these patients. Further prospective controlled studies are necessary to confirm these data.

Laser treatment of feeder vessels in subfoveal choroidal neovascular membranes: a revisitation using dynamic indocyanine green angiography

OBJECTIVE

This study aimed to determine whether the indocyanine green angiography (ICGA)-guided laser treatment of feeder vessels (FVs) may be useful in the management of the subfoveal choroidal neovascular membranes (CNVM) in patients with age-related macular degeneration (ARMD).

DESIGN

Noncomparative case series.

PARTICIPANTS

The authors considered a series of 15 patients with subfoveal CNVM in whom feeder vessels could be clearly detected by means of dynamic ICGA but not necessarily with fluorescein angiography (FA). On the basis of the indications of the pilot study, the authors also studied a second series of 16 patients with FVs smaller than 85 microm.

INTERVENTION

Treatment of FV using argon green laser was performed. The ICGA was performed immediately after treatment, after 2, 7, 30 days, and then every 3 months, to assess FV closure. If an FV appeared to be still patent, it was immediately retreated and the follow-up was started again. The follow-up time ranged from 23 to 34 months for the pilot study and from 4 to 12 months for the second series.

MAIN OUTCOME MEASURES

The obliteration of the membrane and change in visual acuity from baseline were measured. The effect on the treatment of the number and width of the FVs, and the size and location of the membrane, also was evaluated.

RESULTS

In the pilot study, the CNVM was obliterated after the first treatment in only one patient, five patients needed more than one treatment, and obliteration failed in nine patients (40% success rate). The rate of success was affected by the width and number of the FVs. The success rate in the second series of 16 patients was higher (75%).

CONCLUSIONS

The success of the laser treatment of FVs depends on their width, length, and number. Dynamic ICGA, which detects smaller FVs and makes it possible to control the laser effect and initiate immediate retreatment in the case of incomplete FV closure, should be considered mandatory for this type of treatment; a comparable success rate would have been unlikely using the other currently available methods of treating subfoveal CNVMs.

[The photon therapy of subfoveal choroidal neovascularization in age-dependent macular degeneration. The results of a prospective study in 40 patients]

AIM

To determine the effect of external beam radiotherapy on subfoveal choroidal neovascularization in age-related macular degeneration.

PATIENTS AND METHODS

Between September 1995 and July 1996, 40 patients (9 males and 31 females; mean age 74 years, range 61 to 83 years) were included in a prospective study. Eight patients had classic, well-defined neovascularisations, 32 patients had occult lesions. Complete ophthalmic investigations included visual acuity contrast sensitivity as well as fluorescein and indocyanine green angiographic examinations prior to treatment and 1, 3, 6, and 12 months after radiotherapy. External beam radiotherapy (8-MV photons) was delivered with a total dose of 14.4 Gy in 8 fractions of 1.8 Gy per day (Figures 1 and 2). The field size averaged 5.5 x 4.5 cm.

RESULTS

No treatment related morbidity during or after treatment was obtained. After 6 months follow-up the visual acuity was improved in 2 (5%) patients and maintained at pretreatment level in 17 (42%) patients. However, 12 months post treatment a stable situation was found in 6 (15%) patients and a decrease in visual acuity in 34 (85%) patients (Table 1). The central visual fields deteriorated significantly from 16.5 decibel (dB) to 12.4 dB. The enlargement of exudates and neovascular membranes increased 5- to 7-fold. At 12 months after treatment, 3 (7.5%) patients stated that they had improved vision subjectively, 12 (30%) patients had no change and 25 (62.5%) patients suffered from subjective decrease in visual acuity.

CONCLUSIONS

Using a total dose of 14.4 Gy/1.8 Gy no difference concerning visual acuity and exudative changes in comparison to the natural history on age-related macular degeneration was obtained after 12 months. However, the results of multicenter studies are to be awaited.

Age-related macular degeneration: a review of experimental treatments

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the USA. Laser photocoagulation of choroidal neovascular membranes (CNVMs) in exudative AMD is currently the only well-studied and widely accepted treatment modality. It is beneficial for only a small minority of patients who show well-demarcated "classic" CNVMs, and it destroys normal retinal tissue, creates a scotoma, and is associated with an unacceptably high CNVM persistence and recurrence rate. Consequently, investigators have attempted to develop new modalities for treatment of CNVMs. These treatment modalities can be grouped into four major categories: photodynamic therapy; pharmacologic inhibition of CNVM formation with antiangiogenic agents; surgical intervention, including excision of subfoveal CNVMs; and radiation therapy. All of these experimental treatment modalities are directed toward destroyiing CNVMs, the end result of the exudative process, and all have limitations. The ideal treatment of the future must be based on the pathogenesis of the disease at a stage well before CNVMs develop. Investigations in nonexudative AMD are currently focusing on several major areas. Epidemiologic factors, such as genetics, sunlight, and nutrition, are being evaluated in several large studies, including the Age-Related Eye Disease Study, with the possibility of ultimately limiting the risk of AMD through behavior modification. Laser treatment of drusen is being evaluated as a means of limiting the risk of CNVM formation, although mixed results have been reported in the small number of studies to date. Choroidal perfusion abnormalities have been described in AMD, and some investigators postulate that altering blood flow may limit the risk of CNVM formation. No perfusion-treatment trials have been completed to date.

Low dose radiation for subfoveal choroidal neovascularization in age-related macular degeneration. A pilot study: radiotherapy for age-related macular degeneration

The aim of our pilot study was to test the effect of low dose radiation on classic and occult subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (AMD). The posterior pole of the afflicted eye of 12 patients was irradiated with 5 Gray (Gy), and that of 34 patients with 8 Gy. The radiotherapy was done by a linear accelerator (6 MV X-rays) during 4 consecutive days with daily doses of 1.25 Gy and 2 Gy respectively. At the time of treatment, and 6 weeks, 6 months and 1 year after, a simultaneous fluorescein and ICG angiography of both eyes were carried out, and the distance visual acuity was measured. In none of the cases were we able to note a reduction in the subfoveal membrane's size. With regards to the visual acuity, the evolution was slightly better than the spontaneous courses described in existing literature. Further prospective randomized studies with higher dose radiation are necessary in order to determine the significance of radiotherapy in the treatment of this pathology.

Correlation between Octopus perimetry and fluorescein angiography after strontium-90 plaque brachytherapy for subfoveal exudative age related macular degeneration

AIM

To evaluate the correlation between the central visual field and changes in fluorescein angiography and fundus photography in patients treated with strontium plaque radiotherapy for subfoveal exudative age related macular degeneration (AMD).

METHODS

Octopus program 34 automated static perimetry, fluorescein angiography, and colour fundus photography were performed on 19 patients at baseline and at 12 months after strontium-90 plaque therapy. A schematic picture outlining the areas of hyperfluorescent neovascular membranes and subretinal blood was drawn of a projected 30 degrees fundus fluorescein angiogram. This drawing was superimposed on the size adjusted Octopus visual field. The changes in retinal sensitivity were calculated and related to angiographic changes.

RESULTS

Three of the 19 patients had a reliability factor (RF) > 15% and were excluded from further analysis. In the remaining 16 patients the mean defect (MD) and loss variance (LV) values remained unchanged in patients showing regression of the choroidal neovascular membrane (CNVM) to irradiation at 12 months. MD was 7.7 (SD 1.7) at baseline and 7.6 (1.9) at 12 months (p = 0.86), and LV was 32.6 (13.9) at baseline and 32.4 (15.7) at 12 months (p = 0.94). However, in patients with progression of the CNVM at 12 months, both the MD and LV increased significantly during the 12 month follow up (MD from 7.3 (2.9) to 13.1 (3.6) (p = 0.05) and LV from 31.0 (22.9) to 71.8 (24.1) (p = 0.017)). When comparing the mean retinal sensitivity in the area of the primary CNVM (including classic, occult, and haemorrhagic components), the results were analogous: in patients with a regression of the CNVM after irradiation the mean sensitivity remained almost unchanged. It was 10.3 (6.4) dB at baseline and 9.4 (7.3) dB at 12 months (p = 0.58). In five out of 11 patients (45%) with regression of the CNVM, the mean retinal sensitivity even improved by 2.0-5.0 dB in the area of the original lesion during follow up. Instead, in patients showing progression of the CNVM at 12 months, there was a significant loss in mean retinal sensitivity--from 9.9 (4.6) dB at baseline to 1.0 (1.1) dB at 12 months (p = 0.019). The mean retinal sensitivity in the area of the irradiated but clinically normal retina during follow up was not significantly altered (21.5 dB at baseline, 19.7 dB at 12 months (p = 0.10)).

CONCLUSIONS

Regression of subfoveal choroidal membranes in AMD after focal strontium irradiation is connected with stabilisation or even improvement of retinal sensitivity in central visual field measured by automated perimetry. Strontium plaque irradiation does not change the sensitivity in clinically normal paramacular retina during a 12 month follow up.

Use of a simulator with CT option in radiotherapy of macular degeneration

PURPOSE

To assess the accuracy of a conventional simulation procedure in radiotherapy of age-related macular degeneration.

METHODS AND MATERIALS

A computed tomographic (CT) extension attached to the treatment simulator was used to acquire CT images immediately after conventional simulation in 18 patients referred for treatment of age-related macular degeneration. Analysis was performed on 16 one-sided treatment cases for whom images were obtained. Error was estimated by the displacement between the observed treatment isocenter and the intended isocenter based on reconstructed eye geometry.

RESULTS

Based on single slice measurements, the mean error amplitude was 2.3 mm (range 0.2-5.6). Based on three-dimensional eye globe reconstruction, the mean error amplitude was 2.8 mm (range 0.8-5.3). An incidental finding previously unreported was the lower image quality at the center of the simulator-CT image acquisition field.

CONCLUSIONS

Small but significant errors from conventional simulation were noted. The integrated simulation-CT procedure may help correct the errors to improve the accuracy of simulation setup. The lower image quality at the center of image acquisition field requires adaptation of the simulation-CT procedure.

Strontium plaque irradiation of subfoveal neovascular membranes in age-related macular degeneration

PURPOSE

To determine the effect of focal strontium-90 plaque radiotherapy on subfoveal choroidal neovascularization in patients with age-related macular degeneration.

METHODS

Twenty patients with age-related macular degeneration, presenting with a recent subfoveal neovascular membrane, were treated with local episcleral radiotherapy using a strontium-90 applicator. The applicator was applied to the sclera under the macular region and held there tightly for 54 min to obtain a dose of 15 Gy at a depth of 1.75 mm. The main parameters evaluated at follow-up after 3, 6 and 12 months were visual acuity and changes in fluorescein angiography. Twelve untreated patients with the same criteria were followed as controls.

RESULTS

Early effects of radiation could be seen at 3 months, but became more obvious after follow-up for 6 and 12 months. At 6 months, regression of the choroidal neovascularization was detected in 14/19 patients (74%) as a decrease in the size of the lesion or as diminished leakage in late-phase fluorescein angiography. Likewise, in 14/19 patients (74%) at 12 months the neovascular membrane was partially or totally occluded. In all patients showing regression of the choroidal neovascular membrane, the neurosensory detachment had also dried. Visual acuity was unchanged (within 1 line) or improved in 11/20 (55%) and 9/20 (45%) treated patients after 6 and 12 months, respectively. In the controls, the choroidal neovascularization had increased in size in 9/12 patients (75%) at the last follow-up (mean 12.0 months). Visual acuity was unchanged in 3/12 patients (25%).

CONCLUSION

Local low-energy beta irradiation with a strontium-90 applicator can induce regression of choroidal neovascularization. The effect of irradiation is seen as a decrease in the size of the choroidal neovascular membrane and disappearance of the neurosensory detachment and exudates.

Radiation therapy for macular degeneration: technical considerations and preliminary results

PURPOSE

This study was undertaken to assess the toxicity and possible benefits from the administration of low-dose external-beam irradiation for Age-Related Macular Degeneration (ARMD). The premise of the treatment is that radiation induces regression and/or promotes inactivation of the subretinal neo-vasculature, resulting in reabsorption of fluid and blood thus reducing the risk for further leakage or bleeding, as well as subretinal fibrosis. Clinically, the beneficial effect could be translated into stabilization of visual acuity and prevention of progression of the wet type of ARMD with the possibility for some visual improvement.

METHODS AND MATERIALS

Allegheny University Hospitals, Hahnemann, Department of Radiation Oncology, treated 278 patients prospectively beginning in January 1995 with low-dose irradiation for wet-type macular degeneration. Two hundred forty-nine patients were treated with a total dose of 14.40 Gy in eight fractions of 1.80 Gy over 10-13 elapsed days, and 27 patients with 20 Gy at 2 Gy per fraction over 12-15 days. The first two patients were treated to a total dose of 10.00 Gy in five fractions of 2.00 Gy. Patients were evaluated at 2-3 weeks and 2-3 months. A percentage (36.7%) of the patients had previously received laser treatments in the study eye, 21.9% once, 5% twice, 9.7% three or more. Subjective visual acuity and toxicity data was collected on all patients.

RESULTS

At 2-3 weeks after treatment 195 patients (70%) retained their visual acuity without change, 68 patients (24.5%) stated they had improved vision, and 15 patients (4.8%) stated their vision continued to decrease. Two to 3 months after treatment, 183 patients (65.8%) had no change in their vision, 75 patients (27%) had an improvement in their vision, and 20 patients (7.2%) had a decrease in visual acuity. Transient acute reactions occurred in 14 of the 278 patients treated.

CONCLUSION

Our observations in this group of 278 patients support the conclusion that many patients will have improved or stable vision after treatment with low-dose irradiation for age related wet type macular degeneration.

Low-dose radiation therapy for age-related macular degeneration

BACKGROUND

The study was carried out to evaluate the effect of low-dose radiation therapy in patients with age-related macular degeneration.

METHODS

One hundred eyes of 78 patients (mean age 72 years) with different forms of age-related macular degeneration were treated with external beam radiotherapy between 1971 and 1989. In four fractions a total dose of 2 Gy was administered over 7 days. Radiation therapy was performed by the conventional 200-kV technique. The mean duration of follow-up period was 7 years (range 0.5 to 20 years). A control group was composed of 96 eyes from patients with AMD who received no therapy. The mean visual acuity at first presentation and the duration of follow-up was the same as in the treatment group.

RESULTS

No difference in visual acuity between the treatment and control groups could be observed. After 1, 2, 5 and 10 years the mean visual acuity was equal in the radiation group and the control group. Even in subgroup analysis regarding only the eyes with exudative forms of AMD, no effect of this treatment strategy could be demonstrated.

CONCLUSION

Our results suggest that low-dose radiation therapy in patients with age-related macular degeneration has no beneficial effect. However, it must be considered that the dose of 2 Gy is low in comparison to doses used in recently published studies (5-24 Gy).

[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.

Radiation therapy for ocular choroidal neovascularization (phase I/II study): preliminary report

PURPOSE/OBJECTIVE

Choroidal neovascularization (CNV) is a major cause of severe loss of visual acuity in some ocular diseases such as age-related macular degeneration (ARMD) and angioid streaks. Laser photocoagulation has been used to treat patients with subfoveal neovascular lesions with well-demarcated boundaries. However, the treatment method is usually associated with a large decrease in visual acuity. Therefore, indications for this treatment are very limited. Recently, some investigators reported the effect of low dose irradiation on the subretinal neovascular membranes in CNV. We conducted a Phase I/II study to determine the toxicity and efficacy of external photon beam radiotherapy in patients with CNV.

METHODS AND MATERIALS

Between April, 1994 and July, 1995, 36 patients with choroidal neovascularization (34 with ARMD and 2 with angioid streaks) were treated with radiation therapy. Treatment planning was performed using a CT simulator that enables real-time treatment planning from multiple CT slices. The clinical target volume 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 with a single lateral 6 MV photon beam, 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 field size averaged 3.0 x 2.5 cm. Records of the 17 eyes with CNV referred to our hospital in 1993, which satisfied the eligibility criteria for this study, were retrospectively analyzed for comparison.

RESULTS

There was no significant acute morbidity. All patients were followed regularly by both ophthalmologists and radiation oncologists. Cataract formation 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 complained of transient dry-eye sensation 2 months after treatment, but this had disappeared spontaneously by the fourth month. The subjective symptoms, visual acuity, and size of the neovascular membrane were evaluated at 6 and 12 months after treatment in each patient. In the group of patients irradiated with 10 Gy and with 20 Gy, respectively, subjective symptoms improved in five and seven eyes, did not change in seven and four eyes, and deteriorated in six and six eyes at 12 months. Although visual acuity was significantly decreased in the control group, the patients in both irradiated groups did not show such a decrease in visual acuity. The size of the neovascular membrane in the control group progressed significantly. However, the patients in the 20 Gy group showed significant regression of the membrane, although those in the 10 Gy group showed no significant change in size.

CONCLUSION

This Phase 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 multicenter randomized prospective study of the treatment of CNV with radiation therapy.

Indirect scatter laser photocoagulation to subfoveal choroidal neovascularization in age-related macular degeneration

BACKGROUND

Occult choroidal neovascularization (CNV), poorly defined on fluorescein angiography, is present in the majority of patients with exudative complications of age-related macular degeneration. For patients who present with this type of subfoveal CNV but who have useful visual acuity, no form of treatment is of proven benefit. Accordingly, a pilot randomized trial of indirect laser treatment was performed. The rationale of this treatment was to inhibit the CNV through laser-induced effects on the retinal pigment epithelium.

METHODS

Patients with occult subfoveal CNV without retinal pigment epithelial detachment and with visual acuity of 20/200 or better were randomized to treatment or control groups. A grid of laser burns was applied to the macula beyond the area of serous retinal detachment and of angiographically defined occult CNV.

RESULTS

After an average follow-up of 38 months, there was no difference in mean final visual acuity (0.12 treated, 0.14 control) or clinical outcome between treated and untreated groups. Fluorescein angiography showed gradual enlargement in the occult CNV in 58% of eyes in both groups. A decrease in visual acuity to worse than 20/200 (54% of treated, 50% of control eyes) was associated with ingrowth of well-delineated CNV (6 treated, 7 control eyes) or progression to a fibroglial or atrophic scar (11 treated, 8 control eyes).

CONCLUSIONS

No benefit was demonstrated for scatter photocoagulation of the macula in patients with age-related macular degeneration and occult subfoveal CNV with initially good visual acuity. There were, however, no complications related to treatment.