Asymmetry of disciform scarring in bilateral disease when one eye is treated with radiotherapy

Proton beam irradiation with anti-VEGF therapy for polypoidal choroidal vasculopathy: results of a 24-month, phase II randomized study

PURPOSE

To determine the efficacy and safety of proton beam irradiation (PBI) and anti-vascular endothelial growth factor (anti-VEGF) therapy for polypoidal choroidal vasculopathy (PCV)/ aneurysmal type 1 macular neovascularization (AT1).

METHODS

The randomized clinical trial consisted of newly diagnosed active PCV/AT1 patients who were randomized 1:1 to treatment with three initial monthly intravitreal anti-VEGF agent (conbercept) injections with or without single 14 GyE radiation. Subsequent anti-VEGF therapy was given pro re nata. The primary outcome measures were number of anti-VEGF injections, best-corrected visual acuity (BCVA), and central retinal thickness (CRT) at 24 months. Secondary outcome measures included the polypoidal lesion regression rate, changes in the areas of polypoidal lesions and branching vascular network (BVN), and radiotherapy-related adverse events at 24 months.

RESULTS

A total of 45 eyes (86.5%) completed the 24-month follow-up. At 24 months, the combination therapy group required fewer anti-VEGF injections compared with the monotherapy group (5.9 ± 4.1 vs. 8.8 ± 5.3; P = 0.04). The mean gains in BCVA and the mean decrease in CRT were not significantly different between the two groups (P = 0.85 and P = 0.17, respectively). Combination therapy was superior to monotherapy for complete polypoidal lesion regression (80.0% vs. 48%, P = 0.03) and change in BVN area (- 1.03 ± 1.24 mm2 vs. 0.36 ± 0.77 mm2, P < 0.01). The radiation-related microvascular abnormalities were observed in 55.0% of eyes following combination therapy at 15.7 ± 2.5 months.

CONCLUSION

PBI (14 GyE) combined with anti-VEGF therapy could decrease the need for additional anti-VEGF injections for PCV/AT1. Longer follow-up is needed to fully evaluate the long-term safety of PBI.

KEY MESSAGES

What is known The current main methods for treating PCV/AT1 include anti-VEGF drugs as monotherapy or in combination with photodynamic therapy. However, some cases can be challenging with multiple repeated injections due to the relatively low regression rate of polyps and high recurrence rate. What is new Proton beam irradiation therapy with anti-VEGF drugs can synergistically promote the regression of polyps and the shrinkage of branching vascular network, and reduce the anti-VEGF treatment burden for patients with PCV/AT1. Radiation retinopathy was mild and did not appear to be visually significant at the 24-month follow-up. Proton beam irradiation can be a new strategy for the treatment of PCV/AT1.

Context for Protons as Adjunctive Therapy in Neovascular Age-Related Macular Degeneration: A Review

In the last few years we have witnessed increasing availability of proton therapy in the United States and worldwide. As a result, proton therapy is considered as either a primary or adjunctive approach for numerous indications where conventional radiation therapy shows promise but is accompanied by toxicities. Age-related macular degeneration (AMD) remains the leading cause of adult blindness in industrialized nations, and third worldwide, following cataract and glaucoma. Current standard therapy is intravitreal injection of anti-vascular endothelial growth factor agents. While this treatment shows improvement and stabilization in visual acuity for 40% of patients, 60% still experience disease progression. These injections are costly, necessitate repeated office visits, and carry the risk of endophthalmitis. The pathophysiology underlying neovascular AMD (nAMD) underscores the need to simultaneously target multiple pathways to retain useful vision. Radiation can be antiangiogenic, anti-inflammatory, and antiproliferative. Early photon therapy clinical trials were heterogeneous, and a Cochrane review of data demonstrated usefulness in treatment of nAMD but recommended further studies. Advantages of proton therapy over photon therapy include the ability to deliver a focal dose to the target while minimizing dose to normal structures, which is enhanced by unique treatment planning software that uses fluorescein angiography to verify target location and allows conformation of dose to the irregular shape and thickness characteristic of choroidal neovascular membranes, the pathognomonic finding in nAMD. Preliminary data suggest a potential role for proton therapy in the treatment of nAMD. In this article we review previous treatments for AMD, including those with both photon and proton radiation, and recommend future directions for clinical investigations to evaluate the role of proton therapy as an adjunct to antiangiogenic therapy, the current standard of care in this challenging setting.

Epimacular brachytherapy for wet AMD: current perspectives

Age-related macular degeneration (AMD) is considered the most common cause of blindness in the over-60 age group in developed countries. There are basically two forms of presentation: geographic (dry or atrophic) and wet (neovascular or exudative). Geographic atrophy accounts for approximately 85%–90% of ophthalmic frames and leads to a progressive degeneration of the retinal pigment epithelium and the photoreceptors. Wet AMD causes the highest percentage of central vision loss secondary to disease. This neovascular form involves an angiogenic process in which newly formed choroidal vessels invade the macular area. Today, intravitreal anti-angiogenic drugs attempt to block the angiogenic events and represent a major advance in the treatment of wet AMD. Currently, combination therapy for wet AMD includes different forms of radiation delivery. Epimacular brachytherapy (EMBT) seems to be a useful approach to be associated with current anti-vascular endothelial growth factor agents, presenting an acceptable efficacy and safety profile. However, at the present stage of research, the results of the clinical trials carried out to date are insufficient to justify extending routine use of EMBT for the treatment of wet AMD.

Radiation therapy for neovascular age-related macular degeneration

In the enormity of the public health burden imposed by age-related macular degeneration (ARMD), much effort has been directed toward identifying effective and efficient treatments. Currently, anti-vascular endothelial growth factor (VEGF) injections have demonstrated considerably efficacy in treating neovascular ARMD, but patients require frequent treatment to fully benefit. Here, we review the rationale and evidence for radiation therapy of ARMD. The results of early photon external beam radiation therapy are included to provide a framework for the sequential discussion of evidence for the usage of stereotactic radiation therapy, proton therapy, and brachytherapy. The evidence suggests that these 3 modern modalities can provide a dose-dependent benefit in the treatment of ARMD. Most importantly, preliminary data suggest that all 3 can be used in conjunction with anti-VEGF therapeutics, thereby reducing the frequency of anti-VEGF injections required to maintain visual acuity.

The age-related macular degeneration radiotherapy trial (AMDRT): one year results from a pilot study

PURPOSE

To assess the short-term safety and efficacy of treating subfoveal choroidal neovascularization (CNV) with external beam radiation delivered in 5 x 4 Gy fractions among patients having age-related macular degeneration (AMD).

DESIGN

A multicenter prospective randomized controlled pilot study.

METHODS

Eighty-eight patients were enrolled through 10 sites and were randomized to radiotherapy (20 Gy delivered in 5 daily fractions of 4 Gy each; 6 MV [N = 41]) or no radiotherapy (sham radiotherapy [N = 22] or observation [N = 25]). Eligibility criteria included visual acuity of at least 20/320 and subfoveal CNV not amenable to treatment. Randomization was stratified by lesion type (new or recurrent CNV) and blood (<50% or >/=50% of the lesion [N = 13]). The primary outcome measure was loss of >/=3 lines of visual acuity. Secondary outcome measures were angiographic response and side effects.

RESULTS

At baseline, patient and ocular characteristics were similar between treatment groups. At six months, 9 radiated eyes (26%) and 17 eyes not radiated (49%) lost >/=3 lines of visual acuity (P = .04; stratified chi(2) test). At 12 months, 13 radiated eyes (42%) and 9 observed eyes (49%) lost >/=3 visual acuity lines (P = .60). The radiated group demonstrated smaller lesions and less fibrosis than the nonradiated group (P = .05 and .004, respectively) at 12 months. Radiation-induced complications were not observed except for one radiated eye with numerous cotton wool spots and possible radiation retinopathy.

CONCLUSIONS

External beam radiation at 5 x 4 Gy may have a modest and short-lived (six month) benefit in preserving visual acuity.

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.

Radiation-associated choroidal neovasculopathy

PURPOSE

To characterize a newly discovered choroidal vascular abnormality in patients who have received radiation therapy for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration.

DESIGN

Two-center cross-sectional study.

PARTICIPANTS

In the United States, there were 95 patients who were treated with 10 or 12 Gy of external beam photons. In Belgium, 98 patients were treated with 20 Gy. These patients were examined retrospectively for the presence of a specific CNV abnormality.

RESULTS

During the follow-up period, an unusual vascular growth pattern was identified in 12 patients (12.6%) of those treated in the United States and in 7 (7.1%) of those treated in Belgium. These patients developed round or oval vascular blebs along the outer border of their neovascular lesions. These blebs profusely leaked fluorescein dye and could be imaged best by indocyanine green angiography. Patients with these blebs appeared to have a marked propensity for loss of visual acuity.

CONCLUSION

An unusual pattern of new vessel growth occurred in 19 of the 193 patients with CNV treated with radiation. This new entity, termed radiation-associated choroidal neovasculopathy, is a recognizable disorder that appears to have a particularly poor prognosis.

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.

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.

Randomized trial of radiation for age-related macular degeneration

PURPOSE

To assess external beam radiation efficacy for subfoveal neovascularization associated with age-related macular degeneration.

METHODS

All patients were evaluated in the same institution. In this prospective trial, 27 eyes (27 patients) with subfoveal neovascularization associated with age-related macular degeneration were randomized to either single fraction radiation (750 centigray) or observation. Endpoints were assessed by fluorescein angiography and Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity. Examiners were masked to patient treatment status. Parametric and nonparametric statistical analyses were performed.

RESULTS

Twenty-seven patients were entered into the trial with a mean age of 76 years (range, 64 to 89) and a mean follow-up of 17 months (range, 7 to 32). The visual acuity loss was slightly less in the irradiated group, a finding of borderline significance (P < .046). There was no significant difference in fluorescein angiographic evidence of subretinal neovascular membrane change in the control group vs the irradiated group.

CONCLUSIONS

External beam radiation, at this dose and fractionation, did not appear harmful. There was slightly less visual loss in irradiated eyes. No difference in fluorescein angiographic characteristics of subfoveal neovascularization size or progression in eyes with age-related macular degeneration was noted.

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.

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.

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.

External beam radiotherapy in the management of subfoveal choroidal neovascular membranes of the eye: a new treatment for an old disease

Images

External beam radiation therapy for choroidal neovascularization

OBJECTIVE

This study aimed to determine the effect of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

The study design was a nonrandomized clinical trial with an historic control group.

PARTICIPANTS

A total of 91 patients were treated with external beam radiation. These patients were compared retrospectively to the 119 patients in a control group.

INTERVENTION

Patients with subfoveal CNV who did not meet the criteria for laser treatment defined by published reports from the Macular Photocoagulation Study Group or who did not want laser treatment were considered for radiation therapy in a nonrandomized, prospective clinical trial. Additional entry criteria for this prospective study included visual acuity better than or equal to 20/320 on the Early Treatment Diabetic Retinopathy Study chart and a lesion size less than 12 disc areas. The patients were treated with 5 fractions of 200 cGy 6 MV external beam photons.

MAIN OUTCOME MEASURES

The visual acuity measured at baseline was compared to the visual acuity after 1 year of follow-up.

RESULTS

The mean baseline visual acuity of the 91 patients entered into the Radiation Study was 20/80. After 1 year, 83 patients (91.2%) completed follow-up, and their mean visual acuity dropped to 20/200. By comparison, the mean baseline visual acuity of the control patients also was 20/80, and after 1 year, the control subjects had a mean visual acuity of 20/125. At 1 year of follow-up, 49.4% of patients treated with radiation and 38.1% of the control subjects lost 3 or more lines of visual acuity (P = 0.16).

CONCLUSIONS

This study found that external beam radiation using 1000 cGy in 5 fractions, a dose similar to that used in previous studies, was not effective in the treatment of CNV secondary to AMD. These results suggest that patients should not be treated with this dose of external beam radiation for CNV secondary to AMD.

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.

[Radiotherapy and age-related macular degeneration: a review of the literature]

Macular degeneration is a major health problem. Less than 10% of the cases can be successfully treated by laser therapy. Low dose radiation therapy (in the range of 20 Gy) appears to decrease neovascularisation. These early results need to be confirmed through a randomized trial.

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.

External radiotherapy in macular degeneration: technique and preliminary subjective response

PURPOSE

This study attempted to assess the toxicity and possible preliminary 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 neovasculature which would result in reabsorption of fluid and blood. This would reduce the risk for further leakage or bleeding, as well as subretinal fibrosis. Consequently, the beneficial effect could be translated into stabilization of visual acuity and prevention of progression of the wet ARMD with the possibility for slight improvement.

METHODS AND MATERIALS

Allegheny University Department of Radiation Oncology treated 41 patients prospectively from January through October 1995 with low-dose irradiation for wet-type macular degeneration. A total of 39 patients were treated with a total dose of 14.4 Gy in eight fractions of 1.8 Gy/fraction over 10-13 elapsed days. The first two patients were treated with a total dose of 10 Gy in five fractions of 2 Gy. Patients were evaluated at 2-3 weeks and 2-3 months. Some of the patients (36.7%) had laser treatments in the study eye: 21.9% (9) once, 5% (2) twice, 9.7% (4) thrice or more. Subjective visual acuity and toxicity data were collected on all patients.

RESULTS

At 2-3 weeks after treatment 29 patients (70%) retained their visual acuity without change, 10 (24.5%) stated they had improved vision, and 2 (4.8%) stated their vision continued to decrease. At 2-3 months after treatment, 27 patients (65.8%) had no change in their vision, 11 (27%) had an improvement in their vision, and 3 (7.2%) had a decrease in visual acuity. Six patients of 41 in the treated group had acute transient side effects.

CONCLUSION

Our observations in this group of 41 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.

Radiotherapy treatment of age-related subfoveal neovascular membranes in patients with good vision

This prospective study investigated whether low-dose ionising radiotherapy preserved vision and caused membrane regression in patients with age-related subfoveal neovascular membranes (SFNVMs) or vascularised pigment epithelial detachments (PEDs) and relatively good initial visual acuities. Twenty-five patients with initial Snellen acuities of 6/24 or better were treated with low-dose external beam radiotherapy. Of the patients with SFNVMs, visual acuities were maintained or improved in 58% at 6 months and 53% at 1 year. Neovascular membrane size was assessed by image analysis and showed some regression in 47% and 41% at 6 and 12 months respectively. These results suggest that patients with SFNVMs and good vision may benefit from radiotherapy, faring better than previous reports of the natural history of this condition. Conversely, patients with vascularised PEDs did not appear to benefit from radiotherapy. Only 17% maintained their vision at 1 year and 33% suffered retinal pigment epithelial tears. The results from patients with SFNVMs and good initial vision, excluding those with vascularised PEDs, are encouraging however, any benefit from this treatment needs to be proven by controlled trials with long follow-up.

Visual acuity and scar size in eyes with age-related subfoveal choroidal neovascular lesions, 30 months after radiation therapy

PURPOSE

In a study to determine the effectiveness of ionizing radiation on the deterioration of visual acuity (VA) due to choroidal neovascularisation (CNV) the affected eyes of 10 patients were treated with a total dose of 24 Gy (6 Gy fractions). A special lens-sparing technique was used to avoid cataract development. During 30 months of follow-up the visual acuity (VA) and scar size (SS) of the treated eyes and fellow eyes of all 10 patients were evaluated.

RESULTS

After 30 months of follow-up 5 eyes showed a stable VA and fluorescein angiogram (FA) appearance. Concerning 4 out of 5 eyes with progressive disease, the 4 eyes treated with radiation therapy had better VA and smaller SS as compared with the untreated fellow eyes with exudative AMD.

CONCLUSIONS

The results suggest that 24 Gy either stabilizes or delays the deleterious effects of CNV on the visual acuity. Until now no late side effects have been observed.