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

Radiotherapy for neovascular age-related macular degeneration

BACKGROUND

Radiotherapy has been proposed as a treatment for new vessel growth in people with neovascular age-related macular degeneration (AMD).

OBJECTIVES

To examine the effects of radiotherapy on neovascular AMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS and three trials registers and checked references of included studies. We last searched the databases on 4 May 2020.  SELECTION CRITERIA: We included all randomised controlled trials in which radiotherapy was compared to another treatment, sham treatment, low dosage irradiation or no treatment in people with choroidal neovascularisation (CNV) secondary to AMD.

DATA COLLECTION AND ANALYSIS

We used standard procedures expected by Cochrane. We graded the certainty of the evidence using GRADE. We considered the following outcomes at 12 months: best-corrected visual acuity (BCVA) (loss of 3 or more lines, change in visual acuity), contrast sensitivity, new vessel growth, quality of life and adverse effects at any time point.  MAIN RESULTS: We included 18 studies (n = 2430 people, 2432 eyes) of radiation therapy with dosages ranging from 7.5 to 24 Gy. These studies mainly took place in Europe and North America but two studies were from Japan and one multicentre study included sites in South America. Three of these studies investigated brachytherapy (plaque and epimacular), the rest were studies of external beam radiotherapy (EBM) including one trial of stereotactic radiotherapy. Four studies compared radiotherapy combined with anti-vascular endothelial growth factor (anti-VEGF) with anti-VEGF alone. Eleven studies gave no radiotherapy treatment to the control group; five studies used sham irradiation; and one study used very low-dose irradiation (1 Gy). One study used a mixture of sham irradiation and no treatment. Fifteen studies were judged to be at high risk of bias in one or more domains. Radiotherapy versus no radiotherapy There may be little or no difference in loss of 3 lines of vision at 12 months in eyes treated with radiotherapy compared with no radiotherapy (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.64 to 1.04, 811 eyes, 8 studies, I² = 66%, low-certainty evidence). Low-certainty evidence suggests a small benefit in change in visual acuity (mean difference (MD) -0.10 logMAR, 95% CI -0.17 to -0.03; eyes = 883; studies = 10) and average contrast sensitivity at 12 months (MD 0.15 log units, 95% CI 0.05 to 0.25; eyes = 267; studies = 2). Growth of new vessels (largely change in CNV size) was variably reported and It was not possible to produce a summary estimate of this outcome. The studies were small with imprecise estimates and there was no consistent pattern to the study results (very low-certainty evidence). Quality of life was only reported in one study of 199 people; there was no clear difference between treatment and control groups (low-certainty evidence). Low-certainty evidence was available on adverse effects from eight of 14 studies. Seven studies reported on radiation retinopathy and/or neuropathy. Five of these studies reported no radiation-associated adverse effects. One study of 88 eyes reported one case of possible radiation retinopathy. One study of 74 eyes graded retinal abnormalities in some detail and found that 72% of participants who had radiation compared with 71% of participants in the control group had retinal abnormalities resembling radiation retinopathy or choroidopathy. Four studies reported cataract surgery or progression: events were generally few with no consistent evidence of any increased occurrence in the radiation group. One study noted transient disturbance of the precorneal tear film but there was no evidence from the other two studies that reported dry eye of any increased risk with radiation therapy. None of the participants received anti-VEGF injections. Radiotherapy combined with anti-VEGF versus anti-VEGF alone People receiving radiotherapy/anti-VEGF were probably more likely to lose 3 or more lines of BCVA at 12 months compared with anti-VEGF alone (RR 2.11, 95% CI 1.40 to 3.17, 1050 eyes, 3 studies, moderate-certainty). Most of the data for this outcome come from two studies of epimacular brachytherapy (114 events) compared with 20 events from the one trial of EBM. Data on change in BCVA were heterogenous (I² = 82%). Individual study results ranged from a small difference of -0.03 logMAR in favour of radiotherapy/anti-VEGF to a difference of 0.13 logMAR in favour of anti-VEGF alone (low-certainty evidence). The effect differed depending on how the radiotherapy was delivered (test for interaction P = 0.0007). Epimacular brachytherapy was associated with worse visual outcomes (MD 0.10 logMAR, 95% CI 0.05 to 0.15, 820 eyes, 2 studies) compared with EBM (MD -0.03 logMAR, 95% CI -0.09 to 0.03, 252 eyes, 2 studies). None of the included studies reported contrast sensitivity or quality of life. Growth of new vessels (largely change in CNV size) was variably reported in three studies (803 eyes). It was not possible to produce a summary estimate and there was no consistent pattern to the study results (very low-certainty evidence). For adverse outcomes, variable results were reported in the four studies. In three studies reports of adverse events were low and no radiation-associated adverse events were reported. In one study of epimacular brachytherapy there was a higher proportion of ocular adverse events (54%) compared to the anti-VEGF alone (18%). The majority of these adverse events were cataract. Overall 5% of the treatment group had radiation device-related adverse events (17 cases); 10 of these cases were radiation retinopathy. There were differences in average number of injections given between the four studies (1072 eyes). In three of the four studies, the anti-VEGF alone group on average received more injections (moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence is uncertain regarding the use of radiotherapy for neovascular AMD. Most studies took place before the routine use of anti-VEGF, and before the development of modern radiotherapy techniques such as stereotactic radiotherapy. Visual outcomes with epimacular brachytherapy are likely to be worse, with an increased risk of adverse events,  probably related to vitrectomy. The role of stereotactic radiotherapy combined with anti-VEGF is currently uncertain. Further research on radiotherapy for neovascular AMD may not be justified until current ongoing studies have reported their results.

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.

Risk of scar in the comparison of age-related macular degeneration treatments trials

OBJECTIVE

To describe risk factors for scar in eyes treated with ranibizumab or bevacizumab for neovascular age-related macular degeneration (AMD).

DESIGN

Prospective cohort study within a randomized clinical trial.

PARTICIPANTS

Patients with no scar on color fundus photography (CFP) or fluorescein angiography (FA) at enrollment in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT).

METHODS

Eyes were assigned to ranibizumab or bevacizumab treatment and to 1 of 3 dosing regimens for 2 years. Masked readers assessed CFP and FA. Baseline demographic characteristics, visual acuity, morphologic features on photography and optical coherence tomography (OCT), and genotypes associated with AMD risk were evaluated as risk factors using adjusted hazard ratios (aHRs) and associated 95% confidence intervals (CIs). Scars were classified as fibrotic with well-demarcated elevated mounds of yellowish white tissue or nonfibrotic with discrete flat areas of hyperpigmentation with varying amounts of central depigmentation.

MAIN OUTCOME MEASURES

Scar formation.

RESULTS

Scar developed in 480 of 1059 eyes (45.3%) by 2 years. Baseline characteristics associated with greater risk of scarring were predominantly classic choroidal neovascularization (CNV) (aHR, 3.1; CI, 2.4-3.9) versus occult CNV, blocked fluorescence (aHR, 1.4; CI, 1.1-1.8), foveal retinal thickness >212 μm (aHR, 2.4; CI, 1.7-3.6) versus <120 μm, foveal subretinal tissue complex thickness >275 μm (aHR, 2.4; CI, 1.7-3.6) versus ≤75 μm, foveal subretinal fluid (aHR, 1.5; CI, 1.1-2.0) versus no subretinal fluid, and subretinal hyperreflective material (SHRM) (aHR, 1.7; CI, 1.3-2.3) versus no SHRM. Eyes with elevation of the retinal pigment epithelium had lower risk (aHR, 0.6; CI, 0.5-0.8) versus no elevation. Drug, dosing regimen, and genotype had no statistically significant association with scarring. Fibrotic scars developed in 24.7% of eyes, and nonfibrotic scars developed in 20.6% of eyes. Baseline risk factors for the scar types were similar except that eyes with larger lesion size or visual acuity <20/40 were more likely to develop fibrotic scars.

CONCLUSIONS

Approximately half of eyes enrolled in CATT developed scar by 2 years. Eyes with classic neovascularization, a thicker retina, and more fluid or material under the foveal center of the retina are more likely to develop scar.

[Adjuvant stereotactic low energy radiation therapy of exudative age-dependent macular degeneration (Oraya system)]

With respect to the increasing number of patients and the risk and burden for patients caused by injections, a reduction in the number and frequency of injections with vascular endothelial growth factor (VEGF) inhibitors in exudative age-related macular degeneration (ARMD) is desirable. Stereotactic low-voltage x-ray irradiation seems to be a promising approach. For this purpose the Oraya system is available and has shown positive results in initial studies. Pending presentation of phase II and III study data this adjuvant irradiation should only be used in clinical trials.

Age-related macular degeneration revisited--piecing the puzzle: the LXIX Edward Jackson memorial lecture

PURPOSE

To present the current understanding of age-related macular degeneration (AMD) pathogenesis, based on clinical evidence, epidemiologic data, histopathologic examination, and genetic data; to provide an update on current and emerging therapies; and to propose an integrated model of the pathogenesis of AMD.

DESIGN

Review of published clinical and experimental studies.

METHODS

Analysis and synthesis of clinical and experimental data.

RESULTS

We are closer to a complete understanding of the pathogenesis of AMD, having progressed from clinical observations to epidemiologic observations and clinical pathologic correlation. More recently, modern genetic and genomic studies have facilitated the exploration of molecular pathways. It seems that AMD is a complex disease that results from the interaction of genetic susceptibility with aging and environmental factors. Disease progression also seems to be driven by a combination of genetic and environmental factors.

CONCLUSIONS

Therapies based on pathophysiologic features have changed the paradigm for treating neovascular AMD. With improved understanding of the underlying genetic susceptibility, we can identify targets to halt early disease and to prevent progression and vision loss.

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.

Remission and dropout rate of anti-VEGF therapy for age-related macular degeneration

PURPOSE

Anti-vascular endothelial growth factor (VEGF) therapy is a first-line treatment for age-related macular degeneration (AMD) but frequent visits and injections can be a burden for patients. The purpose of this study is to estimate the remission rate and tolerability of anti-VEGF therapy for AMD in a clinical setting.

METHODS

We investigated 90 eyes of 87 patients with AMD who underwent anti-VEGF therapy and were followed for more than 6 months. Ranibizumab and pegaptanib were used as anti-VEGF agents. Initial therapy was any of the following: a single injection, 3 consecutive monthly injections, or combination therapy with verteporfin. Additional injections were given as-needed during follow-up. An injection-free period greater than 6 months at the final observation was regarded as cessation; the reason for cessation was studied for each patient. Clinical characteristics were compared between patents with and without cessation.

RESULTS

The mean follow-up period was 12.8 months. Mean logMAR before and 6 months after the treatment was 0.89 and 0.83, respectively. Cessation was noted in 32 eyes of 31 patients (35.6%). Remission was achieved in 13 (40.6%) of these eyes. The other cases either did not wish to undergo further treatment or dropped out. Poor baseline visual acuity (VA) was associated with cessation.

CONCLUSIONS

With current anti-VEGF therapy, remission was achieved in a limited number of AMD cases. The high frequency of voluntary cessation warrants consideration of an alternative treatment and/or supportive care for those with poor baseline VA.

Ten-year follow-up of eyes treated with stereotactic fractionated external beam radiation for neovascular age-related macular degeneration

PURPOSE

To determine the long-term effects of stereotactic fractionated external beam radiation on eyes treated for neovascular age-related macular degeneration.

METHODS

A retrospective review of all eyes treated with stereotactic fractionated external beam radiation (20-40 Gy, 2-Gy fractions) between 1997 and 2000 was performed to identify eyes with ≥ 2-year follow-up for analysis. A subset was imaged prospectively using a high-resolution Fourier-domain optical coherence tomography.

RESULTS

Among 94 eyes treated, 33 eyes (32 subjects) had ≥ 2-year follow-up information (mean follow-up, 6.2 years; range, 2-10 years). Final visual acuity ranged from 20/50 to no light perception. Final macular findings included central geographic atrophy (49%), disciform scar (30%), and active choroidal neovascular membrane (9%). Fourier-domain optical coherence tomography images of three eyes with geographic atrophy revealed photoreceptor layer loss within areas of geographic atrophy with intact retinal morphology in areas of radiation exposure outside geographic atrophy. Radiation retinopathy was suspected in 18% and confirmed by fluorescein angiography in 15%, ranging from mild to neovascular glaucoma/phthisis bulbi (2 eyes). Mean time from stereotactic fractionated external beam radiation to development of radiation retinopathy was 5.4 years (range, 1-10 years).

CONCLUSION

A moderate rate of delayed radiation retinopathy was noted in eyes with neovascular age-related macular degeneration treated with stereotactic fractionated external beam radiation. Geographic atrophy was a common finding.

Radiation maculopathy after epimacular brachytherapy for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration

PURPOSE

To describe a case of radiation maculopathy after a 24-Gy single-fraction epimacular brachytherapy delivered concomitantly with ranibizumab for the treatment of age-related macular degeneration.

METHODS

Case report.

RESULTS

An 82-year-old man with neovascular age-related macular degeneration was treated with epiretinal brachytherapy and 2 intraocular injections of ranibizumab with initial good response. Nineteen months after initial treatment, visual acuity decreased and the patient was diagnosed of radiation maculopathy.

CONCLUSION

Radiation-related ocular side effects such as maculopathy may become evident several years after the treatment. Thus, vascular abnormalities that may appear in the follow-up of these patients can easily be misdiagnosed as a complication of the previous choroidal neovascularization.

Radiotherapy for neovascular age-related macular degeneration

BACKGROUND

Radiotherapy has been proposed as a treatment to prevent new vessel growth in people with neovascular age-related macular degeneration (AMD).

OBJECTIVES

The aim of this review was to examine the effects of radiotherapy on neovascular AMD.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library Issue 3, 2010, MEDLINE (January 1950 to March 2010), EMBASE (January 1980 to March 2010), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2010), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (March 2010) and ClinicalTrials.gov (http://clinicaltrials.gov) (March 2010). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 23 March 2010. We also wrote to investigators of trials included in the review to ask if they were aware of any other studies.

SELECTION CRITERIA

We included all randomised controlled trials in which radiotherapy was compared to another treatment, sham treatment, low dosage irradiation or no treatment in people with choroidal neovascularisation secondary to AMD.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data. We combined relative risks using a random-effects model. We estimated the percentage of the variability in effect estimates that was due to heterogeneity, rather than sampling error, using I(2).

MAIN RESULTS

Thirteen trials (n=1154) investigated external beam radiotherapy with dosages ranging from 7.5 to 24 Gy; one additional trial (n=88) used plaque brachytherapy (15Gy at 1.75mm for 54 minutes/12.6 Gy at 4mm for 11 minutes). Most studies found effects (not always significant) that favoured treatment. Overall there was a small statistically significant reduction in risk of visual acuity loss in the treatment group. There was considerable inconsistency between trials and the trials were considered to be at risk of bias, in particular because of the lack of masking of treatment group. Subgroup analyses did not reveal any significant interactions, however, there were small numbers of trials in each subgroup (range three to five). There was some indication that trials with no sham irradiation in the control group reported a greater effect of treatment. The incidence of adverse events was low in all trials; there were no reported cases of radiation retinopathy, optic neuropathy or malignancy. Three trials found non-significant higher rates of cataract progression in the treatment group.

AUTHORS' CONCLUSIONS

This review currently does not provide convincing evidence that radiotherapy is an effective treatment for neovascular AMD. If further trials are to be considered to evaluate radiotherapy in AMD then adequate masking of the control group must be considered.

Antiangiogenic approaches to age-related macular degeneration today

Intravitreal ranibizumab reduces the risk of visual acuity loss and increases the chance of visual acuity gain compared with no treatment or photodynamic therapy for selected cases of subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (AMD). Although intravitreal ranibizumab did not result in substantial improvement (15 or more letters on an ETDRs chart) in the majority of cases treated in the MARINA (Minimally classic/occult trial of the Anti-VEGF antibody Ranibizumab in the treatment of Neovascular AMD) or ANCHOR (Anti-VEGF Antibody for the Treatment of Predominantly Classic CHORoidal Neovascularization in AMD) trials, few cases experienced substantial visual acuity loss. The most serious known risk of treatment, endophthalmitis, although rare, is always a possibility. Intravitreal bevacizumab might be considered when ranibizumab is not available because of regulatory or financial constraints, and it might be considered in place of ranibizumab even without financial constraints if noninferiority trials show that bevacizumab is almost as good as-or is better than-ranibizumab. Systemic risks of intravitreal ranibizumab or bevacizumab are unknown, although trials have ruled out moderate or large systemic risks for ranibizumab. This therapy should be considered when initiating therapy for lesions that are subfoveal, and predominantly CNV when the lesion composition on fluorescein angiography (FA) is predominantly classic, or when there is presumed recent disease progression and the lesion composition is minimally classic or occult with no classic. Optical coherence tomography, FA, or both also might be of value to assist with decisions regarding continuation of treatment after it has been initiated. However, to date, there is little consistent information to suggest that utilizing these imaging modalities to consider withholding treatment before 2 years has been shown confidently to result in outcomes as good as monthly treatment. Extrapolation of these recommendations should be done with caution when considering the treatment of subfoveal CNV that is not predominantly CNV, such as predominantly blood lesions or lesions that are predominantly scar, as well as lesions associated with very low levels of visual acuity or those owing to causes other than AMD. A subsequent review in this series discusses other therapies for CNV being considered in the future.

Kilovoltage stereotactic radiosurgery for age-related macular degeneration: assessment of optic nerve dose and patient effective dose

Age-related macular degeneration (AMD) is a leading cause for vision loss for people over the age of 65 in the United States and a major health problem worldwide. Research for new treatments of the wet form of the disease using kilovoltage stereotactic radiosurgery is currently underway at Oraya Therapeutics, Inc. In the present study, the authors extend their previous computational stylized model of a single treated eye [Med. Phys. 35, 5151-5160 (2008)] to include full NURBS-based reference head phantoms of the adult male and female using anatomical data from ICRP Publication 89. The treatment was subsequently modeled in MCNPX 2.5 using a 1 x 1 x 1 mm3 voxelized version of the NURBS models. These models incorporated several organs of interest including the brain, thyroid, salivary glands, cranium, mandible, and cervical vertebrae. A higher resolution eye section at 0.5 x 0.5 x 0.5 mm3 voxel resolution was extracted from the head phantoms to model smaller eye structures including the macula target, cornea, lens, vitreous humor, sclera/retina layer, and optic nerve. Due to lack of literature data on optic nerve pathways, a CT imaging study was undertaken to quantify the anatomical position of the optic nerve. The average absorbed doses to the organs of interest were below generally accepted thresholds for radiation safety. The estimated effective dose was 0.28 mSv which is comparable to diagnostic procedures such as a head radiograph and a factor of 10 lower than a head CT scan.

Dosimetry characterization of a multibeam radiotherapy treatment for age-related macular degeneration

Age-related macular degeneration (ARMD) is a major health problem worldwide. Advanced ARMD, which ultimately leads to profound vision loss, has dry and wet forms, which account for 20% and 80% of cases involving severe vision loss, respectively. A new device and approach for radiation treatment of ARMD has been recently developed by Oraya Therapeutics, Inc. (Newark, CA). The goal of the present study is to provide a initial dosimetry characterization of the proposed radiotherapy treatment via Monte Carlo radiation transport simulation. A 3D eye model including cornea, anterior chamber, lens, orbit, fat, sclera, choroid, retina, vitreous, macula, and optic nerve was carefully designed. The eye model was imported into the MCNPX2.5 Monte Carlo code and radiation transport simulations were undertaken to obtain absorbed doses and dose volume histograms (DVH) to targeted and nontargeted structures within the eye. Three different studies were undertaken to investigate (1) available beam angles that maximized the dose to the macula target tissue, simultaneously minimizing dose to normal tissues, (2) the energy dependency of the DVH for different x-ray energies (80, 100, and 120 kVp), and (3) the optimal focal spot size among options of 0.0, 0.4, 1.0, and 5.5 mm. All results were scaled to give 8 Gy to the macula volume, which is the current treatment requirement. Eight beam treatment angles are currently under investigation. In all eight beam angles, the source-to-target distance is 13 cm, and the polar angle of entry is 300 from the geometric axis of the eye. The azimuthal angle changes in eight increments of 45 degrees in a clockwise fashion, such that an azimuthal angle of 0 degreee corresponds to the 12 o'clock position when viewing the treated eye. Based on considerations of nontarget tissue avoidance, as well as facial-anatomical restrictions on beam delivery, treatment azimuthal angles between 135 degrees and 225 degrees would be available for this treatment system (i.e., directly upward and entering the eye from below). At beam directions approaching 225 degrees and higher, some dose contribution to the optic nerve would result under the assumption that the optic nerve is tilted cranially above the geometric axis in a given patient, a feature not typically seen in past studies. A total treatment dose of 24 Gy would be delivered in three 8 Gy treatments at these selected azimuthal angles. Dose coefficients, defined as the macula radiation absorbed dose per unit air kerma in units of Gy/Gy, were 16% higher for 120 kVp x-ray beams in comparison to those at 80 kVp, thus requiring only 86% of the integrated tube current (mAs) for equivalent dose delivery. When 0.0, 0.4, and 1.0 mm focal spot sizes were used, the dose profiles in the macula are very similar and relatively uniform, whereas a 5.5 mm focal spot size produced a more nonuniform dose profile. The results of this study dem onstrate the therapeutic promise of this device and provide important information for further design and clinical implementation for radiotherapy treatments for ARMD.

Use of 'sham' radiotherapy in randomized clinical trials

The objective of this systematic review was to identify quality trials that use sham radiotherapy in their design and review them to determine its potential value. The Cochrane Library, Pubmed and a Reference Search served as data sources. Trials were included if they met a minimum quality score of 3 on a validated assessment instrument (which assesses randomization, control and blinding) and if they compared sham radiotherapy to active treatment. External beam therapy and brachytherapy trials were considered. Twenty-six trials were identified, collectively including 2663 participants in the period of 1970-2004. All the trials studied the value of radiotherapy for treatment or prevention of benign diseases, including multiple sclerosis, coronary artery restenosis, age-related macular degeneration and Graves' ophthalmopathy. There were no trials relating to the use of radiotherapy in the treatment of malignancy. This review showed that it is possible to carry out sham radiotherapy with due regard for ethical concerns, with effective blinding and high levels of patient acceptance. Large sample sizes with multicentre trial designs were achievable. Although the statistical philosophy for using sham radiotherapy in trials is legitimate, it is no longer routinely used.

Vascular endothelial growth factor in eye disease

Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the US, for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis.

The Natural History and Prognosis of Neovascular Age-Related Macular Degeneration

PURPOSE

To describe the natural history and progression of visual loss in eyes with untreated neovascular age-related macular degeneration (AMD).

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Four thousand three hundred sixty-two untreated neovascular AMD patients from published interventional studies.

METHODS

A systematic review of the literature from 1980 to August 2005 was performed. Studies reporting disease progression outcomes for untreated patients with neovascular AMD were included. Outcome measures were summarized using simple counts and means. Random effects meta-analyses were conducted and tests of heterogeneity were performed where appropriate.

MAIN OUTCOME MEASURES

Changes in visual acuity (VA) loss, development of comorbidities, and fellow eye involvement.

RESULTS

Fifty-three primary studies were included. Nearly half of the studies (28) were randomized clinical trials. The quality of the studies was high, with over 80% providing level I or II evidence. Mean baseline VA among study patients was 0.64 logarithm of the minimum angle of resolution (logMAR) (approximately 20/87 Snellen). The mean VA change in logMAR progressed from 0.1 (1 line lost) at 3 months to 0.3 (2.7 lines lost) after 12 months and 0.4 (4 lines lost) after 24 months. The proportion of patients who developed severe vision loss (>6 lines) from baseline increased from 21.3% at 6 months to 41.9% by 3 years. The proportion of patients with VA worse than logMAR 1.0 (20/200 Snellen) increased from 19.7% at baseline to 75.7% by 3 years. Neovascular AMD developed in the fellow eye in 12.2% of patients by 12 months and in 26.8% by 4 years. Meta-analyses of vision outcome by subtype of neovascular AMD were not possible.

CONCLUSIONS

A doubling of the visual angle of presenting VA may be expected to occur in the year after initial presentation in eyes with untreated neovascular AMD. No conclusions can be drawn as to the differences in rates of disease progression by neovascular AMD subtype. The diversity of reporting formats, paucity of long-term natural history data, and heterogeneity among the reported clinical studies impose limits to the clear understanding of long-term prognosis for visual function in neovascular AMD.

The long-term effect of experimental beta-radiation therapy on the human cornea

BACKGROUND

Radiation treatment of the human eye has been utilized in the United States since the early 1900s. Beta-radiation therapy was generally accepted by the medical community as a treatment option for a wide variety of anterior and posterior segment conditions from 1930 to the early 1950s. By the 1960s, beta-radiation therapy had fallen out of favor due to dangerous side effects; however an updated radiation procedure is now in use in ophthalmology to treat anterior and posterior segment disease.

CASE REPORT

A 64-year-old Caucasian female presented for a routine eye examination with a history of experimental beta-radiation treatments to the eyes as a teenager. A high astigmatic refractive error was present and best corrected visual acuity was 20/40 OD, 20/30 OS. Slit lamp examination showed severe disruption throughout the lower third of both corneas, appearing densely calcified with inferior vascularization. The left eye had a central descemetocele. The patient's ocular and visual conditions were relatively stable and required no special treatment as of the writing of this report, decades after her original treatments.

CONCLUSION

This patient is one example of the long-term effect of beta-radiation treatment on the eye. Ongoing care is needed to monitor the ocular health and vision of these individuals as radiation effects may necessitate observation and/or care throughout the patient's lifetime. Follow-up on more patients who underwent beta-radiation treatment decades ago, should it be possible to do so, would provide further insight into the long-term anterior segment changes that can occur as a result of such treatment.

Proton Beam Irradiation for Neovascular Age-Related Macular Degeneration

OBJECTIVE

To evaluate safety and visual outcomes after proton therapy for subfoveal neovascular age-related macular degeneration (AMD).

DESIGN

Randomized dose-ranging clinical trial.

PARTICIPANTS

One hundred sixty-six patients with angiographic evidence of classic choroidal neovascularization resulting from AMD and best-corrected visual acuity of 20/320 or better.

METHODS

Patients were assigned randomly (1:1) to receive 16-cobalt gray equivalent (CGE) or 24-CGE proton radiation in 2 equal fractions. Visual acuity was measured using standardized protocol refraction. Complete ophthalmological examinations, color fundus photography, and fluorescein angiography were performed before and 3, 6, 12, 18, and 24 months after treatment.

MAIN OUTCOME MEASURE

Proportion of eyes losing 3 or more lines of vision from baseline. Kaplan-Meier statistics were used to compare cumulative rates of vision loss between the 2 treatment groups.

RESULTS

At 12 months after treatment, 36 eyes (42%) and 27 eyes (35%) lost 3 or more lines of vision in the 16-CGE and 24-CGE groups, respectively. Rates increased to 62% in the 16-CGE group and 53% in the 24-CGE group by 24 months after treatment (P = 0.40). Radiation complications developed in 15.7% of patients receiving 16 CGE and 14.8% of patients receiving 24 CGE.

CONCLUSIONS

No significant differences in rates of visual loss were found between the 2 dose groups. Proton radiation may be useful as an adjuvant therapy or as an alternative for patients who decline or are not appropriate for approved therapies.

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.

Scientific and medical aspects of ozone therapy. State of the art

The aim of this review is to dispel misconceptions and skepticism regarding ozone therapy and to clarify the biochemical and pharmacological mechanisms of action of ozone dissolved in biological fluids. The work performed in the last decade in our laboratory allows drawing a comprehensive framework for understanding and recommending ozone therapy in some diseases. It is hoped that this report will open a dialogue among clinical scientists and will inform physicians about the beneficial effects of ozone therapy.

Choroidal endothelial cells transmigrate across the retinal pigment epithelium but do not proliferate in response to soluble vascular endothelial growth factor

The purpose of this study was to investigate the effects of soluble VEGF on human choroidal endothelial cell (CEC) transmigration across an RPE monolayer as it relates to choroidal neovascularization in AMD. In coculture assays, ARPE-19 (ARPE) was plated on the undersides of Transwell inserts having 0.4 microm pores. Primary human CECs were then plated into the insert. CECs in the Transwell inserts were counted after 72 hr of growth. CEC proliferation was also measured after culturing CECs in ARPE-CEC coculture-conditioned media or in media with exogenous VEGF121 and/or VEGF165 added. Transmigration assays were performed on Transwells with 8.0 microm pores: green-labelled CECs were plated in Transwell inserts with or without red-labelled ARPE plated on the undersides of the insert. In some transmigration assays, ARPE was plated into the wells to provide a chemotactic gradient for CEC transmigration. After 72 hr CECs were plated, green cells were counted either within the well media as CECs that transmigrated the epithelial monolayer, or on the underside of the insert as CECs that transmigrated the Transwell insert to but not beyond the ARPE monolayer. A neutralizing antibody to VEGF was added to the wells of Transwells at the time the CECs were plated in the insert and transmigrated CECs were counted. VEGF protein was measured in the conditioned media of ARPE and CEC coculture and in transmigration assays. Compared to control, CEC proliferation significantly increased when CECs were cultured in coculture conditioned media (p=0.001) or in coculture assays (p<0.001). However, there was no effect on CEC proliferation when VEGF121, VEGF165, or both were added to solo CECs. Antibody to VEGF did not reduce the proliferative effects of coculture conditioned media on CEC. ARPE plated in the well significantly increased CEC transmigration (p<0.001) compared to transmigration assays without ARPE in the well. VEGF protein measured in the well media of transmigration assays having ARPE within the well was significantly greater than in the assays without ARPE within the well (p<0.004). Exogenous neutralizing antibody to VEGF significantly reduced transmigration, and this effect was dose-dependent. VEGF provides a chemotactic gradient for human CECs to transmigrate across a monolayer of ARPE. Neutralization of VEGF in the media partially reduces transmigration. Whereas soluble VEGF does not increase proliferation of solo CECs, coculture conditioned media enhances proliferation, suggesting that growth factors other than VEGF cause CEC proliferation. These findings may have relevance to the transformation of occult CNV into CNV within the neurosensory retina in AMD.

Subthreshold transpupillary thermotherapy of the retina and experimental choroidal neovascularization in a rat model

PURPOSE

To study the effect of subthreshold transpupillary thermotherapy (TTT) on the retina and experimental choroidal neovascularization (CNV) in the rat.

METHODS

Subthreshold TTT was performed on normal Brown Norway rats or those with krypton laser-induced CNV and appropriate controls with an 810-nm diode laser coupled to a slit lamp. At different intervals after TTT, fundus fluorescence angiography (FFA) and histopathological examinations were performed. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) was used to detect apoptosis. Immunohistochemistry was used to detect heat shock protein 70 (Hsp70) expression.

RESULTS

In normal retina, edema and whitening was found on day 1 after TTT. Different degrees of hyperfluorescence could be seen on FFA. Obvious retina damage, especially in the outer layers, was observed by histology in all the lesions that appeared whitened. In the CNV there was congestion and less damage in the overlying retina than in normal retina on day 1 after TTT. Apoptosis was detected in all retinal layers and CNV lesions by TUNEL. In normal eyes, after TTT, Hsp70 expression was increased in the inner layers of the retina and some of the cells in the choroid. Hsp70 was also increased in laser-induced CNV. Two weeks after TTT, the CNV showed a tendency for fibrosis by Masson staining. FFA did not show much change in the CNV lesions 2 weeks after TTT.

CONCLUSION

Subthreshold TTT has adverse effects on the overlying retina and thus is likely to cause significant functional and morphological long-term sequelae. Subthreshold TTT can cause apoptosis in laser-induced CNV in rats.

Treatment of age-related macular degeneration

Age-related macular degeneration (AMD) is the greatest cause of legal blindness in the western world. Established treatments include argon laser photocoagulation of extrafoveal choroidal neovascularisation (CNV) and photodynamic therapy of selected sub-foveal CNV. Newer approaches are targeting the angiogenic pathway in CNV development. Currently, other treatment modalities, such as radiotherapy and transpupillary thermotherapy do not have a clear role to play. Surgical options are experimental and only available in some centres for selected patients. Prevention of AMD remains elusive. Dietary supplements may have a role, while statins and prophylactic laser photocoagulation of drusen remain experimental. This paper explains the principles behind these approaches.

Age-related macular degeneration--emerging pathogenetic and therapeutic concepts

Today, the average life expectancy in developed nations is over 80 years and climbing. And yet, the quality of life during those additional years is often significantly diminished by the effects of age-related, degenerative diseases, including age-related macular degeneration (AMD), the leading cause of blindness in the elderly worldwide. AMD is characterized by a progressive loss of central vision attributable to degenerative and neovascular changes in the macula, a highly specialized region of the ocular retina responsible for fine visual acuity. Estimates gathered from the most recent World Health Organization (WHO) global eye disease survey conservatively indicate that 14 million persons are blind or severely visually impaired because of AMD. The disease has a tremendous impact on the physical and mental health of the geriatric population and their families and is becoming a major public health burden. Currently, there is neither a cure nor a means to prevent AMD. Palliative treatment options for the less prevalent, late-stage 'wet' form of the disease include anti-neovascular agents, photodynamic therapy and thermal laser. There are no current therapies for the more common 'dry' AMD, except for the use of antioxidants that delay progression in 20%-25% of eyes. New discoveries, however, are beginning to provide a much clearer picture of the relevant cellular events, genetic factors, and biochemical processes associated with early AMD. Recently, compelling evidence has emerged that the innate immune system and, more specifically, uncontrolled regulation of the complement alternative pathway plays a central role in the pathobiology of AMD. The complement Factor H gene--which encodes the major inhibitor of the complement alternative pathway--is the first gene identified in multiple independent studies that confers a significant genetic risk for the development of AMD. The emergence of this new paradigm of AMD pathogenesis should hasten the development of novel diagnostic and therapeutic approaches for this disease that will dramatically improve the quality of our prolonged lifespan.

La radiothérapie des affections bénignes : quelles indications huit ans plus tard ?

The authors present an update version of the indications for radiotherapy in the management of benign diseases. This is based on available randomized trials and recent international meetings. Validated indications remain the prevention of resected heterotopic bone ossifications, keloïds scars and pterygium and also treatment of arteriovenous malformations; the place of radiotherapy for malignant exophtalmia is more and more restricted. Randomized trials have demonstrated the efficacy of endobrachytherapy in the prevention of restenosis after angioplasty but the use of embedded stent has replaced this indication. Macular degeneration is no more an indication of radiotherapy. Quality requirements for radiotherapy are identical for benign or malignant indications.