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.

External beam radiotherapy for age-related macular degeneration causes transient objective changes in tear-film function

PURPOSE

Dry-eye symptoms have been described as possible radiation side effects after external beam radiotherapy for age-related macular degeneration. We therefore investigated tear-film function before and after treatment.

METHODS

Thirty-nine patients with no apparent history of dry-eye symptoms were treated with a 6 MV linear accelerator using a 2x2 cm lateral field angled 10 degrees posteriorly. A total dose of 20 Gy, divided into 10 fractions of 2 Gy and administered 3 times a week, was delivered. Before and 1, 3, and 6 months after radiotherapy, tear secretion was measured by means of tear-film fluorophotometry. The fellow eyes served as controls.

RESULTS

At baseline, mean tear secretion as measured by tear-film fluorophotometry was 7.15 microl/min in the eyes receiving radiation and 5.89 microl/min in the control eyes. No statistically significant differences were found between the two eyes at baseline (signed rank test). One month after treatment, again no significant differences could be found between the two eyes; 3 months after radiation, however, tear secretion was significantly lower in the irradiated eyes than in the fellow eyes (P=0.0017). Six months after treatment this effect could no longer be detected.

CONCLUSION

External beam radiotherapy using 20 Gy in 10 fractions and a 2x2 cm lateral field causes a statistically significant difference in tear secretion 3 months after radiation. This effect seems to be transient, as it had disappeared in later follow-up examinations.

[Indications for radiotherapy of benign lesions: yesterday, today and tomorrow]

A better knowledge of the radiobiological effects and the control of the techniques of dosimetry led to a renewed interest for the radiotherapy of the benign lesions. The doses used for these indications are weaker than those recommended for treatment of cancer and the radiobiological mechanisms implied are different. The aim of this review of the literature is to specify the radiobiological mechanisms, the risks and the place of ionizing radiations during the processing of the benign lesions. Although the risk of radiation induced neoplasms remains a limiting factor of the indications, those are very varied. Some indications are well accepted such as keloid, cerebral arteriovenous malformations, graves' ophtalmopathy, prevention of postoperative heterotopic bone formations; and some others remain still controversial such as the prevention of the post angioplasty restenosis and age-related macular degeneration.

[Radiotherapy of age-related macular degeneration]

The authors evaluate results of the radiotherapy by age-related macular degeneration. They have been performed in Department of Ophthalmology of Teaching Hospital of Charles University in Hradec Králové from February 1999 to June 2000. Our group consisted of 23 patients (23 eyes), 10 males and 13 females in age from 41 to 83 years, with average of 69 yrs. They were evaluated 6 months after begin of radiotherapy. The patients were divided into 2 groups. 11 patients with the entry visual acuity 6/60-6/24 and 12 patients with the entry visual acuity 0.25/50-3/50. The study proved the fact that it is possible to treat the exudative form of age-related macular degeneration using radiotherapy.

Radiotherapy of exudative age-related macular degeneration; a clinical and pathologic study

BACKGROUND

Radiotherapy has recently been employed to treat patients with exudative macular degeneration in order to prevent severe visual loss. Radiotherapy affects the evolution of exudative macular degeneration directly by endothelial toxicity, leading to capillary closure, and/or indirectly through its attenuating effects on the inflammatory response, mediated by macrophages and other inflammatory cells.

METHODS

In this study we describe the histopathologic findings in a patient with exudative age-related macular degeneration (AMD) in both eyes whose right eye was treated with radiotherapy (5 times 2 Gy) 3 years before he died. The eyes were enucleated post mortem and investigated by light microscopy. Additionally, immunohistochemical investigation with antibodies against CD34 and CD68 was performed to identify patent endothelial cells and macrophages.

RESULTS

Both eyes showed neovascular AMD consisting of mixed fibrocellular and fibrovascular membranes. Capillaries in both the choriocapillaris and the neovascular membrane were patent in both eyes. Macrophages were present in the choroidal neovascularization of both eyes. Neither preexistent choroidal, intraretinal, nor neovascular vessels showed increased wall thickness as sign of radiation damage.

CONCLUSION

No radiation-related histopathologic effect could be demonstrated 3 years after radiation therapy in this patient with AMD.

[3 years experience with low dosage fractionated percutaneous teletherapy in subfoveal neovascularization. Clinical results]

AIM

The effect of low dose fractionated percutaneous teletherapy to visual acuity and the changes in subfoveolar neovascular membranes in age-related macular degeneration were investigated.

PATIENTS AND METHOD

126 eyes of 118 patients (age 55-89 years; mean 74 ys.) were treated. Best distal and near visual acuity was assessed prior to (= initial visual acuity [IVA]) and 3, 6, 12, 18, 24, 30 and 36 months after teletherapy. Fluorescein angiography was performed prior to and 6, 12, 24 and 36 months after radiation therapy. For analysis patients were divided into different groups by IVA and membrane size. Maximal duration of observation was 36 months. Teletherapy was done by a 9-MeV photon linear accelerator through a lateral port in half-beam technique with a single dose of 2 Gy up to a total dose of 20 Gy within 12 days.

RESULTS

No severe negative side effects have been observed. Eight patients reported of epiphora and four patients complained of transient sicca syndrome. Visual acuity decreased more than one line in the group IVA 0.05-0.2. The group IVA 0.3-0.5 remained unchanged for 1 year. We found a tendency for increased visual acuity in group IVA > or = 0.6 for 18 months. After that time both groups showed decreased visual acuity, but all these patients reported of reduced metamorphopsia and increased color and contrast perception.

CONCLUSIONS

There is an influence of low dose fractionated percutaneous teletherapy on visual acuity, subfoveal neovascular membranes and metamorphopsia. IVA and duration of anamnesis play an important role. There seems to be no persistent effect; possibly increased dosage will bring a benefit.

Dosimetric advantages of enhanced dynamic wedge in small field irradiation for the treatment of macular degeneration

Exudative macular degeneration is a process that affects the central retina and is the chief cause of blindness in people over 55 years old. Radiation appears to improve or stabilize visual acuity in some of these patients, although definitive clinical studies are ongoing. The delivery of radiation in patients with macular degeneration is unique and challenging because of the location of the surrounding structures, such as the lens and the opposite retina. The "standard" treatment technique has been an anterior oblique beam 20 degrees above lateral to limit dose to these structures. In preference to the undesirable hot spot caused by this single-beam technique, we have employed a superior and inferior oblique pair utilizing the Enhanced Dynamic Wedge (EDW). Couch rotation was used to establish the desired treatment angles. The anterior half of the fields were blocked with the asymmetric jaw (AJ). Studies were performed to determine the value of these methods in reducing lens dose. Although the peripheral dose measurements at Dmax using a 60 degrees metal wedge for > or = 10 cm square fields were higher than for an open field or the EDW, for the small retinal fields there was no lens-dose reduction attributable to the EDW. However, the steep wedge angles achievable with the EDW were useful for optimizing the dose distribution for the most desirable field angles. As expected, the independent collimator was more effective in reducing transmitted dose to the lens than a typical Cerrobend block. Measurements required to predict dose in and out of the field are discussed along with the dosimeters employed in evaluating small fields (less than 5 cm square) with the EDW. The technical challenges of positioning, immobilization, treatment planning and treatment delivery are presented.

Radiation therapy for small choroidal neovascularization in age-related macular degeneration

PURPOSE

To evaluate the effects of radiation therapy on age-related macular degeneration with subfoveal or juxtafoveal choroidal neovascularization < or =1 disc area.

METHODS

Fourteen patients (14 eyes) received a total radiation dose of 10-20 Gy in 5-10 fractions. The mean follow-up time was 22 months. Ten patients (10 eyes) in a control group were followed up for an average of 16 months without treatment.

RESULTS

At a 12-month posttreatment examination, funduscopic and angiographic findings showed improvement in 7 eyes (50%), no change in 1 eye (7%), and deterioration in 6 eyes (43%) among the treated patients. The same findings demonstrated improvement in 1 eye (10%), no change in 2 eyes (20%), and deterioration in 7 eyes (70%) among the control patients. This difference was determined to be statistically significant between the two groups by the Mann-Whitney U-test. Visual acuity had improved in 4 eyes (29%), was unchanged in 6 eyes (43%), and had declined in 4 eyes (29%), among the treated patients. Among the control patients, visual acuity had improved in none of the eyes (0%), was unchanged in 6 eyes (60%), and had declined in 4 eyes (40%). The difference in visual acuity between the two groups was not statistically significant.

CONCLUSIONS

Radiation therapy inhibited small choroidal neovascularization, as seen by funduscopy and angiography, but its effectiveness in improving visual prognosis was not always evident.

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.

[Brachytherapy in the treatment of age-related macular degeneration]

Low-dose radiotherapy by local applicators--Ru106--plaques at a retinal apex dose of 1000-1500 cGy offers a method to treat subretinal neovascularisation by age related macular degeneration without destroying the overlying retina.

Morphologic characteristics of disciform scarring after radiation treatment for age-related macular degeneration

OBJECTIVE

To investigate the influence of radiation therapy on the development of disciform lesions in patients with age-related macular degeneration (AMD).

DESIGN

A prospective, nonrandomized, comparative trial (patient self-controlled).

PARTICIPANTS

Forty eyes with exudative AMD involving the central fovea in 40 consecutive patients were enrolled in this study.

INTERVENTION

Radiation was administered to the posterior pole with an 8-mV photon beam from a linear accelerator. A dose of 14.4 Gy, 1.8 Gy per day, five fractions per week was delivered through a single port.

MAIN OUTCOME MEASURES

The visual acuity and the morphologic characteristics, demonstrated by fundus photography, fluorescein, and indocyanine green angiography, were investigated before treatment and every 3 months after treatment over a period of 24 months. In 10 patients with bilateral disease the disciform lesions were compared.

RESULTS

Twenty five patients could be followed regularly over the period of 24 months. The disciform lesions occurring after radiation were classified in three types. Type I (10 patients) was characterized by being smaller than 2 DD in size, with little fibrotic tissue underneath the retina, but pronounced retinal pigment epithelial changes. Type II (seven patients) showed extensive growth of the choroidal neovascularization (CNV) extending to and beyond the arcades with angiographically active loops in the peripheral parts. Eight patients had type III lesions develop characterized by a size greater than 2 DD but fewer than 6 DD and by a different amount of fibrotic tissue, hemorrhage, and lipid. Type I scarring was significantly associated with occult CNV without pigment epithelial detachments, whereas type II scarring was associated with classic CNV at the initial presentation (P<0.05).

CONCLUSIONS

Although no severe side effects have been reported after radiation therapy for AMD, a subgroup of patients may experience extensive growth of CNV after radiation, causing greater functional damage than occurs spontaneously.

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.

[Radiotherapy of non-malignant diseases: principles and recommendations]

The plenty options and high quality of radiation therapy for non-malignant disorders is not well known outside the field of radiology. It is necessary to transfer this information to cooperating general practitioners, surgeons, orthopedics and other specialists. To warrant quality assurance and quality control and to allow a uniform performance of radiotherapy of non-malignant conditions, general guidelines and recommendations according to the German Working Group of Scientific Medical Societies are useful. This paper summarizes the essential aspects of radiotherapy for non-malignant diseases: indication of, informed consent for, documentation and conduct of radiation therapy for non-malignant diseases using orthovoltage equipment and specific recommendations for follow up examinations. Radiotherapy concepts for non-malignant diseases are summarized.

External beam radiotherapy in exudative age-related macular degeneration: a pooled analysis of phase I data

In recent years external beam radiotherapy (EBRT) has been proposed as a treatment for the wet form of age-related macular degeneration (AMD) where choroidal neovascularization (CNV) is the hallmark. While the majority of pilot (Phase I) studies have reported encouraging results, a few have found no benefit, i.e. EBRT was not found to result in either improvement or stabilization of visual acuity of the treated eye. The natural history of visual loss in untreated CNV of AMD is highly variable. Loss of vision is influenced mainly by the presenting acuity, and size and composition of the lesion, and to a lesser extent by a variety of other factors. Thus the variable outcome reported by the small Phase I studies of EBRT published to date may simply reflect the variation in baseline factors. We therefore obtained information on 409 patients treated with EBRT from eight independent centres, which included details of visual acuity at baseline and at subsequent follow-up visits. Analysis of the data showed that 22.5% and 14.9% of EBRT-treated eyes developed moderate and severe loss of vision, respectively, during an average follow-up of 13 months. Initial visual acuity, which explained 20.5% of the variation in visual loss, was the most important baseline factor studied. Statistically significant differences in loss of vision were observed between centres, after considering the effects of case mix factors. Comparisons with historical data suggested that while moderate visual loss was similar to that of the natural history of the disease, the likelihood of suffering severe visual loss was halved. However, the benefit in terms of maintained/improved vision in the treated eye was modest.

[Radiotherapy for age-related macular degeneration: risk factors of complications, prevention and treatment of side-effects]

PURPOSE

To analyze the retinal and choroidal side-effects of radiotherapy given for age-related macular degeneration (ARMD) and to describe the risk factors of these complications and their treatment.

MATERIAL

and methods: Two hundred and ninety five eyes in 270 patients with ARMD were treated using radiotherapy. Nineteen patients had diabetes. The doses were as follows: 15 Gy or less (4 eyes); 16 Gy/4 fractions (113 eyes); 18 Gy/5 fractions (35 eyes); 20 Gy/5 fractions (123 eyes); 24 Gy/6 fractions (2 eyes); 28.8 Gy/8 fractions (17 eyes); more than 28.8 Gy (1 eye). Patients had a regular follow-up visit with visual acuity, contrast sensitivity evaluation, biomicroscopic fundus examination, fluorescein and ICG angiographies every six months over a mean period of 15 months.

RESULTS

Radiation retinopathy was noted in 15 eyes, a bilateral neovascular glaucoma in one patient, ischemic optic neuropathy in 5 eyes, choroidal telangiectasiae in 19 eyes, venous occlusion in 2 eyes, oedematous retinopathy with major exudation (ORME) in 31 eyes, and choroidal hematoma in 8 eyes. Radiation retinopathy, choroidal telangiectasiae and ORME were related to radiation dose. Radiation retinopathy was more severe and more frequent in patients with diabetes. Choroidal telangiectasiae were diagnosed with ICG angiography and were treated early with laser.

CONCLUSION

Radiotherapy for ARMD should not be done in patients with diabetes. Hypofractionation is not recommended. ICG angiography should be considered essential in the follow-up of patients treated with radiotherapy.