Collaborative Ocular Melanoma Study Group. Incidence of cataract and outcomes after cataract surgery in the first 5 years after iodine 125 brachytherapy in the Collaborative Ocular Melanoma Study: COMS Report No. 27

Cataract Extraction After Brachytherapy for Malignant Melanoma of the Choroid in a Young Female Patient: A Case Report

The use of brachytherapy, a form of radiation therapy, plays a crucial role in the management of intraocular melanomas of the choroid. Ionization radiation treatment has the unfortunate side effect of developing cataracts prematurely. We present an uncommonly seen case of a 36-year-old woman who presented with blurred vision in her left eye following successful plaque radiotherapy four years prior for malignant melanoma in the same eye. The patient had developed a cataract, which hindered her visual acuity and visualization of the tumor. Prompt cataract surgery after brachytherapy for radiation-induced cataracts is necessary for the improvement of the quality of life and ensuring effective uveal and retinal examination.

Plaque Radiotherapy for Ocular Melanoma

Plaque radiotherapy is an effective treatment modality for medium-sized ocular tumors such as uveal melanoma. The authors review the available literature and concisely summarize the current state of the art of ophthalmic plaque brachytherapy. The choice of radioisotope, which includes Ruthenium-106 and Iodine-125, depends on the intended treatment duration, tumor characteristics, and side effect profiles. Ophthalmic plaques may be customized to allow for the delivery of a precise radiation dose by adjusting seed placement and plaque shape to minimize collateral tissue radiation. High dose rate (HDR) brachytherapy, using beta (e.g., Yttrium-90) and photon-emitting sources (e.g., Ytterbium-169, Selenium-75), allows for rapid radiation dose delivery, which typically lasts minutes, compared to multiple days with low-dose plaque brachytherapy. The efficacy of Ruthenium-106 brachytherapy for uveal melanoma varies widely, with reported local control rates between 59.0% and 98.0%. Factors influencing outcomes include tumor size, thickness, anatomical location, and radiation dose at the tumor apex, with larger and thicker tumors potentially exhibiting poorer response and a higher rate of complications. Plaque brachytherapy is effective for selected tumors, particularly uveal melanoma, providing comparable survival rates to enucleation for medium-sized tumors. The complications of plaque brachytherapy are well described, and many of these are treatable.

Association of female sex with cataract surgery in the general population but not in plaque brachytherapy-treated uveal melanoma patients

Cataract is a leading cause of blindness worldwide, necessitating a deeper understanding of its risk factors. We analyzed two cohorts: 1000 individuals from the general Swedish population and 933 patients who received plaque brachytherapy for uveal melanoma. Using Kaplan-Meier and cumulative incidence analyses, as well as Cox and competing risk regressions, we assessed whether there is a relationship between sex and cataract surgery. In the general population, female sex was a significant risk factor for cataract surgery, with a 10-year incidence of 16% compared to 10% for males (subdistribution hazard ratio adjusted for age, 1.35, P < 0.001). In the brachytherapy cohort, female sex was not associated with an increased incidence of cataract surgery, with a 10-year incidence of 25% versus 23% for males (HR 1.08, P = 0.61). Visual acuity at the time of cataract surgery did not significantly differ between sexes in either cohort, suggesting that differences in surgery rates are not due to health-seeking behavior or surgery assessment thresholds. These findings indicate that female sex is associated with a higher risk of cataract surgery in the general population, but not among those treated with plaque brachytherapy for uveal melanoma.

External Beam Radiotherapy in the Management of Uveal Melanoma

OPINION STATEMENT

Uveal melanoma is the most common primary ocular tumor in adults. With the evidence demonstrating that episcleral plaque brachytherapy (EPB) has similar survival rates as enucleation in the Collaborative Ocular Melanoma Study (COMS), eye-sparing treatments have come to the fore today. External radiotherapy techniques (proton beam radiotherapy and stereotactic radiosurgery/fractionated stereotactic radiosurgery) are an important treatment option for globe-sparing treatments. There are no prospective randomized trials comparing these techniques; however, retrospective series, meta-analyses, and reviews indicate that these EPB and external radiotherapy techniques are equal. With this review, we aimed to examine the external radiotherapy techniques used in the treatment of uveal melanoma in detail with reference to the current literature.

Treatment-Related Complications and Functional Results after Ruthenium-106 Brachytherapy in Small to Medium Size Uveal Melanomas (Part 2)

PURPOSE

To analyze the treatment-related complications after ruthenium-106 brachytherapy in patients with uveal melanoma in terms of radiation-induced optic neuropathy, maculopathy and retinopathy, radiation-related vitreous hemorrhage, and retinal detachment, as well as secondary glaucoma and radiogenic cataract. In addition, the course of visual acuity was analyzed.

PATIENTS/METHODS AND MATERIALS

This retrospective study included 608 patients treated with ruthenium-106 brachytherapy between January 2008 and December 2010 at the Department of Ophthalmology, University Hospital Essen. The follow-up time was 11 years. The occurrence of the radiation-induced complications was analyzed using the Kaplan-Meier method. Cox regression was used for univariate and multivariate risk factor analyses. Hazard ratios were calculated for each variable.

RESULTS

Regarding the complications, 34% (N = 207) of the patients had no reported side effects or complications during follow-up. Radiation optic neuropathy was observed in 18.8% (N = 114) of the patients, with a median time to onset of 16 months (range: 3 - 78 months). Radiation maculopathy occurred in 8.2% (N = 50) after a median time of 17 months (range: 3 - 67 months). Radiation retinopathy was observed in 20.1% (N = 122), with a median time to onset of 21 months (range: 6 - 67 months). Secondary glaucoma developed in 9.7% of the patients (N = 53) and radiogenic cataract in 46.8% (N = 227). Vitreous hemorrhage (11.8%, N = 72) and scleral necrosis (2.1%, N = 13) occurred relatively rarely.

CONCLUSION

The observed radiogenic complication rate is comparable with that reported in previous studies.

Incidence, risk factors and outcomes of cataract surgery after plaque brachytherapy for posterior uveal melanoma

Purpose

To examine incidence, risk factors, and outcomes of cataract surgery after plaque brachytherapy for posterior uveal melanoma.

Design

Retrospective interventional cohort study contrasted with general population data.

Methods

All patients treated with plaque brachytherapy for a posterior uveal melanoma at Sweden's national referral center between 2010 and 2022 were included (n = 933). These patients were cross-referenced with data from the Swedish National Cataract Register. Competing risk incidences and outcomes of cataract surgery were compared with a random sample of 1000 individuals from the general population.

Results

The 12-year incidence of cataract surgery after plaque brachytherapy was 27 % (95 % CI 23-31 %), which markedly exceeded the incidence of 16 % in the general population (95 % CI 13-18 %, Gray's P < 0.001). Patients treated with Iodine-125 had significantly higher incidence than patients treated with Ruthenium-106, and the latter had greater incidence than the general population (P < 0.001). In univariate competing risk regressions, older patients, female sex, thick tumors, and Iodine-125 were associated with cataract surgery. In multivariate analysis, older patients and Iodine-125 retained their significance. Outcomes of cataract surgery were overall similar in the plaque brachytherapy and general population, but the general population more often received post op. topical NSAID.

Conclusions

In this study, plaque brachytherapy for posterior uveal melanoma was associated with a significantly increased incidence of cataract surgery. Treatment with the gamma emitting isotope iodine-125 and older patient age at the time of brachytherapy emerged as the major risk factors. Outcomes of cataract surgery were comparable to the general population.

Novel intraocular shielding device for eye plaque brachytherapy using magnetite nanoparticles: A proof-of-concept study using radiochromic film and Monte Carlo simulations

PURPOSE

Eye plaque brachytherapy is a mainstay treatment for uveal melanomas despite potential toxicities to normal tissues. This work proposes a nanoparticle ferrofluid as a novel intraocular shielding device. With a modified magnetic plaque, the shielding particles are drawn to the tumor surface, attenuating dose beyond the tumor while maintaining prescription dose to the target.

METHODS AND MATERIALS

Ferromagnetic nanoparticles suspended in a silicone polymer were synthesized to provide a high-density shielding medium. The ferrofluid's half-value layer (HVL) was quantified for 125I photons using radiochromic film and Monte Carlo methods. A magnetic COMS plaque was created and evaluated in its ability to attract ferrofluid over the tumor. Two ferrofluid shielding mediums were evaluated in their ability to attenuate dose at adjacent structures with in vitro measurements using radiochromic film, in addition to Monte Carlo studies.

RESULTS

The shielding medium's HVL measured approximately 1.3 mm for an 125I photon spectrum, using film and Monte Carlo methods. With 0.8 mL of shielding medium added to the vitreous humor, it proved to be effective at reducing dose to normal tissues of the eye. Monte Carlo-calculated dose reductions of 65%, 80%, and 78% at lateral distances 5, 10, and 18 mm from a tumor (5-mm apical height) in a modeled 20-mm COMS plaque.

CONCLUSIONS

The magnitude of dose reduction could reduce the likelihood of normal tissue side effects for plaque brachytherapy patients, including patients with normal tissues close to the plaque or tumor. Additional studies, safety considerations, and preclinical work must supplement these findings before use.

Side Effects of Proton Beam Radiotherapy Treatment on Iris Melanoma

PURPOSE

This study evaluated the functional outcome and ocular side effects of patients receiving proton beam radiotherapy (PBR) for the treatment of iris melanoma (IM).

DESIGN

This retrospective study analyzed prospectively collected data.

PARTICIPANTS

Patients with IM who underwent PBR as a primary treatment.

METHODS

Treatment was given in the form of whole PBR (wPBR: n = 51) or segmental PBR (sPBR: n = 98).

MAIN OUTCOME MEASURES

Visual acuity (VA) and side effects were divided into ocular surface disease (OSD), secondary glaucoma, or cataract development.

RESULTS

A total of 149 eyes of 149 patients with a mean age of 53.9 ± 16.0 years were included. Tumor recurrence developed in 3 patients (wPBR: 1/51; sPBR: 2/98). Ocular surface disease was observed in 78.4% of the wPBR group (40/51) and 25.5% of the sPBR group (25/98) (P < 0.001) after 0.7 ± 1.2 years and 1.1 ± 0.9 years, respectively. The main side effect was dry eye syndrome in both groups, but severe side effects such as limbal stem cell failure were found only in the wPBR group (4/51; 7.8%). Secondary glaucoma developed in 31.4% of the wPBR group (16/51) compared with 1.0% in the sPBR group (1/98; P < 0.001). Glaucoma control was generally achieved with eye drops, whereas surgery was necessary in 5 patients (wPBR: 4/51, 7.8%; sPBR: 1/98, 1%). Cataract surgery was performed in 47.9% of the wPBR group (23/48) and 19.8% of the sPBR group (19/96) (P < 0.001). Before treatment, VA was 0.14 ± 0.27 logarithm of the minimum angle of resolution (logMAR) in the wPBR group and 0.04 ± 0.19 logMAR in the sPBR group. A worsening was seen in the wPBR group (0.55 ± 0.16 logMAR; P < 0.001) 6 months after radiotherapy, which normalized after 12 months (0.15 ± 0.30 logMAR; P = 0.17). In the sPBR group, no such decrease in VA was observed (6 months: 0.03 ± 0.22 logMAR, P = 0.54; 12 months: 0.04 ± 0.21 logMAR, P = 0.98).

CONCLUSIONS

Our results demonstrate that PBR is a very successful treatment option for patients with IM, showing a high tumor control rate and relatively low complication profile. Tumor recurrence was a rare event, and secondary enucleation was not necessary in any patient. Side effects are commonly seen, but severe side effects such as limbal stem cell failure or secondary glaucoma mainly developed after wPBR. These results are important for clinical decision making and discussion with the patient regarding this form of radiotherapy.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Radiotherapy in Uveal Melanoma: A Review of Ocular Complications

Uveal melanoma represents the most prevalent form of primary malignant intraocular tumor in adults. Historically, enucleation was considered the gold-standard approach in the treatment of uveal melanoma. Currently, radiotherapy is the most commonly used therapy, aiming at a better quality of life. However, radiotherapy can result in several ocular complications, some of which may be vision-threatening. Radiation-induced dry eye, scleral necrosis, cataract, rubeosis iridis, neovascular glaucoma, radiation retinopathy, maculopathy, and optic neuropathy are the most common complications. This article aims to summarize the current literature regarding the ocular complications after radiotherapy, as well as their clinical features, risk factors, and management strategies. A thorough understanding of these issues is crucial for ophthalmologists and oncologists to provide optimal patient care, improve visual outcomes, and minimize long-term complications.

Early treatment and toxicity outcomes for small posterior uveal melanomas treated using custom loaded eye plaques

Introduction

Iodine-125 loaded Collaborative Ocular Melanoma Study plaques can achieve excellent tumor control for patients diagnosed with uveal melanomas. Our ocular cancer team hypothesized that use of novel, partially loaded COMS plaques could ease and improve accurate plaque placement during treatment of small, posterior tumors while providing equivalent tumor control.

Materials/methods

Records of 25 patients treated with custom plaques were compared to 20 patients treated with fully loaded plaques, who had received treatment prior to our institution's adopting the use of these partial plaques. Tumors were matched with regards to location and dimensions as measured by the ophthalmologist. Retrospective analysis of dosing parameters, tumor control and toxicity outcomes were performed.

Results

There were no cancer related deaths, local recurrences or metastases in either cohort at an average follow up of 24 months for patients treated with custom plaques and 60.7 months for patients treated with fully loaded plaques. No statistically significant difference was found in regards to post-operative development of cataracts (χ² = 0.76) or radiation retinopathy (χ² = 0.22). Patients treated with custom loaded plaques noted significantly less clinical visual loss (χ² = 0.006) and were more likely to have vision preserved at ≥20/200 (χ² = 0.006).

Conclusion

Treatment of small, posterior uveal melanomas with partially loaded COMS plaques results in equivalent survival and recurrence outcomes as treatment with fully loaded plaques, while exposing the patient to less radiation. Additionally, treatment with partially loaded plaques reduces the incidence of clinically significant visual loss. These promising early results support the use of partially loaded plaques in well-selected patients.

Ocular Brachytherapy (Interventional Radiotherapy): Preserving the Vision

Uveal melanoma represents the most common intraocular neoplasia among adults. Brachytherapy (interventional radiotherapy; IRT) has a great advantage, when compared with enucleation, both in terms of organ and function sparing. The Collaborative Ocular Melanoma Study introduced into clinical practice a standardised procedure that allowed the equivalence of IRT with enucleation in terms of overall survival to be demonstrated. IRT is carried out by placing a plaque in direct contact with the sclera under the uveal melanoma. Several radioactive sources may be used, including 106-ruthenium, 125-iodine, 103-palladium and 90-strontium. It is a multidisciplinary procedure requiring the collaboration of interventional radiation oncologists and ophthalmologists in the operating theatre and medical physicists for an accurate treatment time calculation. It also relies on ultrasound imaging to identify the lesion and verifiy the correct plaque placement. An emerging tool of paramount importance could be the use of artificial intelligence and predictive models to identify those patients at higher risk of developing late side-effects and therefore who may deserve preventive and supportive therapies.

Analysis of dose to the macula, optic disc, and lens in relation to vision toxicities - A retrospective study using COMS eye plaques

PURPOSE

The aim of this study was to relate common toxicity endpoints with dose to the macula, optic disc, and lens for uveal melanoma patients treated with Iodine-125 Collaborative Ocular Melanoma Study (COMS) eye plaque brachytherapy.

METHODS

A cohort of 52 patients treated at a single institution between 2005 and 2019 were retrospectively reviewed. Demographics, dosimetry, and clinical outcomes were recorded. Univariate, relative risk, and Kaplan-Meier analyses were performed to relate dose to toxicity endpoints including retinopathy, vision decline, and cataracts.

RESULTS

By the end of follow up (Median = 3.6 years, Range = 0.4 - 13.5 years), 65 % of eyes sustained radiation retinopathy, 40 % demonstrated moderate vision decline (>5 Snellen lines lost), and 56 % developed cataracts. Significant (p < 0.05) risk estimates exist for retinopathy and VA decline for doses >52 Gy to the macula and >42 Gy to the optic disc. Moreover, dose to the lens > 16 Gy showed a significant risk for cataract formation. Kaplan-Meier analysis demonstrated significantly different incidence of radiation retinopathy for > 52 Gy to the macula and > 42 Gy to the optic disc. In addition, the Kaplan-Meier analysis showed significantly different incidence of cataract formation for patients with lens dose > 16 Gy.

CONCLUSIONS

Dose-effect relationships exist for the macula and optic disc with respect to the loss of visual acuity and the development of retinopathy. To better preserve vision after treatment, further research is needed to reduce macula, optic disc, and lens doses while maintaining tumor control.

Non-Cancer Effects following Ionizing Irradiation Involving the Eye and Orbit

Simple Summary

The irradiation of tumors involving the eye or orbit represents a complex therapeutic challenge due to the proximity between the tumor and organs that are susceptible to radiation. The challenges include tumor control, as it is often a surrogate for survival; organ (usually the eyeball) preservation; and the minimization of damage of sensitive tissues surrounding the tumor in order to preserve vision. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. The aim of the present review is to report the non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality. The pros and cons of conventional and advanced forms of radiation techniques and their clinical implementation are provided with a clinical perspective.

Abstract

The eye is an exemplarily challenging organ to treat when considering ocular tumors. It is at the crossroads of several major aims in oncology: tumor control, organ preservation, and functional outcomes including vision and quality of life. The proximity between the tumor and organs that are susceptible to radiation damage explain these challenges. Given a high enough dose of radiation, virtually any cancer will be destroyed with radiotherapy. Yet, the doses inevitably absorbed by normal tissues may lead to complications, the likelihood of which increases with the radiation dose and volume of normal tissues irradiated. Precision radiotherapy allows personalized decision-making algorithms based on patient and tumor characteristics by exploiting the full knowledge of the physics, radiobiology, and the modifications made to the radiotherapy equipment to adapt to the various ocular tumors. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. Radiation can damage the lacrimal gland, eyelashes/eyelids, cornea, lens, macula/retina, optic nerves and chiasma, each having specific dose–response characteristics. The present review is a report of non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality.

Fractionated stereotactic radiotherapy for uveal melanoma: Long-term outcome and control rates

Purpose

The aim of our study is to evaluate local tumour control rates, radiation side‐effects, visual preservation and disease‐free survival (DFS) of uveal melanoma (UM) patients treated with fractionated stereotactic radiotherapy (fSRT).

Methods

A retrospective study of UM patients, who were treated with fSRT (N = 189), was performed by the Rotterdam Ocular Melanoma Study group (ROMS), the Netherlands, between 1999 and 2014 with a follow‐up of at least 5 years.

Results

The 1‐, 3‐, 5‐, 10‐ and 15‐year local tumour control rates were as follows: 99.4%, 92.8%, 92.2%, 89.3% and 89.3%, respectively. Cataract (67.8%) was the most common side‐effect of fSRT followed by retinopathy (35.1%), maculopathy (23.8%), vitreous haemorrhage (20.1%), neovascular glaucoma (NVG) (20.0%) and optic neuropathy (12.4%). Patients with anterior located UMs developed cataract more frequently (p = 0.047, multivariable analysis). By multivariable analysis, significant factors for secondary enucleation were tumour recurrence (p < 0.001) and NVG (p < 0.001). In multivariable analysis, risk factors for a worse DFS were larger UM (p = 0.024) and tumours with subretinal fluid (SRF) at baseline (p = 0.038). The 5‐year DFS was 77.0% and the best corrected visual acuity decreased significantly after treatment. After 5 years, 22.0% of patients and after 10 years 17.6% of patients had a visual acuity of ≤0.3 logMAR.

Conclusion

Fractionated stereotactic radiotherapy is a good treatment option for small‐, medium‐ and large‐sized tumours with 5‐year local tumour control of 92.2%. After 5 years, 22.0% of the patients had a good vision. Independently of tumour location, the visual acuity decreased significantly after treatment. Overall, the 5‐year DFS was 77.0%.

Dose characteristics of Au-198 eye brachytherapy applicator: A Monte Carlo study

PURPOSE

The use of ocular plaques is a promising treatment option for eye melanoma brachytherapy. Although several studies have been done on various ocular plaques, little is known about the dose characterization of ¹⁹⁸Au plaque.

MATERIALS AND METHOD

The full mathematical model of the eye phantom, tumor, ¹⁰⁶Ru/¹⁰⁶Rh CCA, and ¹⁹⁸Au plaque were simulated using the Monte Carlo MCNPX code. The dose distribution was measured in the plaque's central axis direction, and a dose profile was also measured at a distance of 2.5 mm from the plaque surface.

RESULTS

The findings showed that ¹⁹⁸Au plaque has superior dosimetric characteristics than CCA plaque for tumors with a thickness of greater than 3.5 mm, while CCA plaque is better for tumors with a thickness of less than 3.5 mm. The dose to the sclera and choroid is higher in the case of CCA plaque, while the dose to the organs at risk (lens and optic nerve) is greater in the case of ¹⁹⁸Au applicator. In the case of ¹⁹⁸Au plaque, however, the dose to sensitive organs was within their permissible dose range.

CONCLUSION

In the treatment of medium and large tumors, ¹⁹⁸Au plaque is more successful than CCA plaque. It can produce a much more homogeneous lateral dose profile in the target. In the treatment of dome-shaped tumors, ¹⁹⁸Au plaque may be more successful than CCA plaque. As a result, the tumor's shape influences the plaque type selection.

Outcomes of cataract surgery in patients previously treated with orbital radiotherapy

PURPOSE

This study aims to quantify the risks of cataract surgery in patients who have previously undergone external beam radiotherapy (EBRT). Cataract is a side effect of this treatment, and the risk of complications following cataract surgery in this cohort is poorly understood.

SETTING

Tertiary ophthalmology and oncology hospital.

DESIGN

Retrospective case series.

METHODS

Patients treated with orbital EBRT at the Beatson West of Scotland Cancer Centre between 2001 and 2019 were identified, and clinical records were reviewed to identify those who had subsequently undergone cataract surgery. Pre- and post-operative case records, and operation records, were reviewed to identify demographic data, and data regarding complications and surgical outcomes.

RESULTS

Forty-six eyes (of 33 patients) were included in this study. The indications for EBRT included thyroid eye disease, lymphoma, choroidal metastases and other orbital malignancies. Mean corrected pre-operative Snellen visual acuity (VA) was 20/100 (range 20/30-20/2000) improving to 20/25 (20/12 to 20/160, one-way ANOVA p<0.01). Mean visual gain was 0.5 LogMAR (-0.9 to 1.9). There was one case of posterior capsule (PC) rupture with vitreous loss (2%). Dense PC plaque was noted intra-operatively in 19.5% (n=9). 13% (n=6) required Nd:YAG laser posterior capsulotomy. There were six cases (13%) of cystoid macular oedema (CMO).

CONCLUSION

Visual outcomes following cataract surgery are similar in this cohort of patients to those obtained in a nationwide cohort. EBRT seems to be associated with an increased incidence of intra-operative PC plaque, post-operative CMO (which in most cases settled with treatment), and need for posterior capsulotomy.

Radiation-induced lens opacities: Epidemiological, clinical and experimental evidence, methodological issues, research gaps and strategy

In 2011, the International Commission on Radiological Protection (ICRP) recommended reducing the occupational equivalent dose limit for the lens of the eye from 150 mSv/year to 20 mSv/year, averaged over five years, with no single year exceeding 50 mSv. With this recommendation, several important assumptions were made, such as lack of dose rate effect, classification of cataracts as a tissue reaction with a dose threshold at 0.5 Gy, and progression of minor opacities into vision-impairing cataracts. However, although new dose thresholds and occupational dose limits have been set for radiation-induced cataract, ICRP clearly states that the recommendations are chiefly based on epidemiological evidence because there are a very small number of studies that provide explicit biological and mechanistic evidence at doses under 2 Gy. Since the release of the 2011 ICRP statement, the Multidisciplinary European Low Dose Initiative (MELODI) supported in April 2019 a scientific workshop that aimed to review epidemiological, clinical and biological evidence for radiation-induced cataracts. The purpose of this article is to present and discuss recent related epidemiological and clinical studies, ophthalmic examination techniques, biological and mechanistic knowledge, and to identify research gaps, towards the implementation of a research strategy for future studies on radiation-induced lens opacities. The authors recommend particularly to study the effect of ionizing radiation on the lens in the context of the wider, systemic effects, including in the retina, brain and other organs, and as such cataract is recommended to be studied as part of larger scale programs focused on multiple radiation health effects.

Radiation Exposure in Orthopaedics

» The damaging effects to human tissue caused by radiation exposure have been documented since the first reports regarding use of radiographs in the late nineteenth century. » Orthopaedic surgeons and residents often are undereducated about the risks associated with radiation exposure and the recommended safety precautions to help mitigate these potential risks. » Orthopaedic surgeons need to adopt the ALARA (as low as reasonably achievable) principle: whenever possible, all available precautions should be taken to keep all members of the operating room safe from radiation exposure while emphasizing the best appropriate care for patients. » An emphasis on radiation safety and protection should be universally incorporated into graduate medical education.

Complications and adverse events of plaque brachytherapy for ocular melanoma

Plaque brachytherapy is a well-accepted modality to manage selected cases of ocular melanoma. Although this modality provides validated oncologic and quality of life benefits, severe complications and adverse events can occur. This article reviews complications and adverse events of plaque brachytherapy, including scleral necrosis, strabismus, cataract, glaucoma, and retinopathies as well as management of these conditions. For practicing oncologists and ophthalmologists, these complications are important to understand, identify, and treat. Additionally, an understanding of common complications of brachytherapy should influence the decision of pursuing it as a treatment option.

Delivered dose changes in COMS plaque-based ocular brachytherapy arising from vitrectomy with silicone oil replacement

PURPOSE

The purpose of the study was to determine dosimetric effects of performing concurrent I-125 Collaborative Ocular Melanoma Study plaque brachytherapy and vitrectomy with replacement using silicone oil, previously shown to be a means of shielding uninvolved parts of the eye.

METHODS AND MATERIALS

Monte Carlo simulations using MCNP6 were performed to compare the dosimetry with all eye materials assigned as water, and for the vitreous (excluding the tumor), composed of polydimethylsiloxane oil for three generic, one large tumor, and two patient geometry scenarios. Dose was scored at the tumor apex, along the sclera, and within a 3D grid encompassing the eye. The assessed patient cases included vitrectomies to treat intraocular pathologies; not to enhance attenuation/shielding.

RESULTS

The doses along the sclera and for the entire eye were decreased when the silicone oil replaced the vitreal fluid, with a maximum decrease at the opposite sclera of 63%. Yet, absolute changes in dose to critical structures were often small and likely not clinically significant. The dose at the tumor apex was decreased by 3.1-9.4%. Dose was also decreased at the edges of the tumor because of decreased backscatter at the tumor-oil interface.

CONCLUSIONS

Concurrent silicone vitrectomy was found to reduce total radiation dose to the eye. Based on current radiation retinopathy predictive models, the evaluation of the absolute doses revealed only a subset of patients in which a clinically significant difference in outcomes is expected. Furthermore, the presence of the silicone oil decreased dose to the tumor edges, indicating that the tumor could be underdosed if the oil is unaccounted for.

The Lens Opacities Classification System III Grading in Irradiated Uveal Melanomas to Characterize Proton Therapy-Induced Cataracts

PURPOSE

To evaluate the use of the Lens Opacities Classification System III grading (LOCS III) for the characterization of radiation-induced cataract, and to correlate the proton beam projection onto the lens with cataract location and grade as defined by the LOCS III.

DESIGN

Prospective, interventional case series.

METHODS

Fifty-two consecutive patients with cataract following proton therapy were included. All cataracts were graded using LOCS III. Relationships between proton beam and cataract subtypes, as well as between dose, proportion of lens irradiated, and extent of cataracts, were assessed.

RESULTS

Tumor diameter, volume, stage, and equatorial tumor location were associated with extent of posterior subcapsular cataracts (PSC) that were diagnosed at a median (interquartile range) 36 months (22;83) after treatment. In multivariate analysis, the tumor volume (P < .01) and an equatorial tumor location (P = .01) were risk factors for extensive PSC. Lens irradiation was avoided in 10 patients. In the remaining 42 patients (81%), the extent of PSC significantly correlated with the dose to the lens receiving 10, 26, and 47 Gy (P = .03, P = .03, and P = .04, respectively), the dose to the lens periphery receiving 10 and 26 Gy (P = .02 and P = .02, respectively), and the dose to the ciliary body receiving 10 and 26 Gy (P = .03 and P = .02, respectively). Nuclear color significantly correlated with the dose to the ciliary body receiving 10 Gy (P = .03) and 26 Gy (P = .02). After adjustment of the results on tumor volume and tumor location, the volume of lens receiving 10 Gy (P = .04) and 26 Gy (P = .03) remained significantly associated with the extent of PSC.

CONCLUSIONS

Proton dose correlated with the occurrence of PSC and nuclear color cataracts as defined by LOCS III grading. Better characterization of cataracts with the LOCS III after irradiation may help to further fill gaps in the current understanding of the mechanisms of radiation-induced cataracts.

Animal models of radiation retinopathy - From teletherapy to brachytherapy

Radiation retinopathy is a serious vision-impairing complication of radiation therapy used to treat ocular tumors. Characterized by retinal vasculopathy and subsequent retinal damage, the first sign of radiation retinopathy is the preferential loss of vascular endothelial cells. Ensuing ischemia leads to retinal degradation and late stage neovascularization. Despite the established disease progression, the pathophysiology and cellular mechanisms contributing to radiation retinopathy remain unclear. Clinical experience and basic research for other retinal vasculopathies, such as diabetic retinopathy and retinopathy of prematurity, can inform our understanding of radiation retinopathy; however, the literature investigating the fundamental mechanisms in radiation retinopathy is limited. Treatment trials have shown modest success but, ultimately, fail to address the cellular events that initiate radiation retinopathy. Animal models of radiation retinopathy could provide means to identify effective therapies. Here, we review the literature for all animal models of radiation retinopathy, summarize anatomical highlights pertaining to animal models, identify additional physiological factors to consider when investigating radiation retinopathy, and explore the use of clinically relevant tests for studying in vivo models of radiation retinopathy. We encourage further investigation into the mechanistic characterization of radiation retinopathy in the hope of discovering novel treatments.

Radiobiological doses, tumor, and treatment features influence on outcomes after epiescleral brachytherapy. A 20-year retrospective analysis from a single-institution: part II

PURPOSE

To assess the influence of the radiobiological doses, tumor, and treatment features on retinopathy, cataracts, retinal detachment, optic neuropathy, vitreous hemorrhage, and neovascular glaucoma at the authors' institution after brachytherapy for posterior uveal melanoma.

MATERIAL AND METHODS

Medical records of 243 eyes with uveal melanoma, treated by iodine brachytherapy between 1996 and 2016 at a single center were analyzed. Clinical and radiotherapy data were extracted from a dedicated database. Biologically effective dose (BED) was included in survival analysis performed using Kaplan-Meier and Cox regressions. Relative survival rates were estimated, and univariate/multivariate regression models were constructed for predictive factors of each item. Hazard ratio and confidence interval at 95% were determined. Variables statistically significant were analyzed and compared by log-rank tests.

RESULTS

The median follow-up was 73.9 months (range, 3-202 months). Cumulative probabilities of survival by Kaplan-Meier analysis at 3 and 5 years, respectively, were: 59% and 48% for retinopathy; 71% and 55% for cataracts; 63% and 57% for retinal detachment; 88% and 79% for optic neuropathy; 87% and 83% for vitreous hemorrhage; 92% and 89% for neovascular glaucoma, respectively. Using multivariate analysis, statistically significant risk factors were: age, tumor apical height, dose to foveola, and location of anterior border for retinopathy; age, dose to lens, type of plaque, and tumor shape, for cataracts; age, tumor apical height, and size of the plaque for retinal detachment; age, plaque shape, longest basal dimension, and BED to optic nerve for optic neuropathy; age, tumor apical height, and tumor shape for vitreous hemorrhage; tumor apical height and BED to foveola for neovascular glaucoma.

CONCLUSIONS

Tumor factors in addition to radiation treatment may contribute to secondary effects. Enhanced clinical optimization should evaluate radiobiological doses delivered to the tumor volume and surrounding normal ocular structures.

Outcomes of cataract surgery in eyes with ocular melanoma treated with iodine-125 brachytherapy

PURPOSE

To evaluate visual and surgical outcomes of cataract surgery in eyes with a history of iodine-125 (I¹²⁵) brachytherapy for ocular melanoma.

SETTING

Department of Ophthalmology, David Geffen School of Medicine at UCLA and the Stein Eye Institute, Los Angeles, California, USA.

DESIGN

Retrospective case series.

METHODS

Patients with ocular melanoma treated by I¹²⁵ brachytherapy who subsequently had cataract surgery were evaluated. The recorded data included tumor size, location, preoperative ocular comorbidities, corrected distance visual acuity (CDVA), operative complications, and brachytherapy-related maculopathy before and after surgery.

RESULTS

Thirty-two eyes of 32 patients were included. The mean age at the time of cataract surgery was 66.1 years. The median follow-up was 53.5 months. There were no intraoperative complications. Eighteen eyes (56.3%) had a history of preoperative radiation retinopathy, 10 involving the macula. Between 2 weeks and 4 weeks postoperatively, 22 eyes (68.8%) had an improvement in CDVA (≥2 lines). Seven of 10 eyes that failed to improve had radiation maculopathy. By the last follow-up examination, 13 eyes (40.6%) had improved CDVA, 9 eyes (28.1%) were worse (≥2 lines), and 10 eyes (31.3%) were unchanged (within ±1 line). Of 15 eyes that lost CDVA gains achieved between 2 weeks and 4 weeks postoperatively, 9 eyes had new-onset or worsening maculopathy. Cataract surgery had no effect on local tumor control or distant metastasis.

CONCLUSIONS

Cataract surgery after I¹²⁵ brachytherapy for ocular melanoma improved CDVA in most eyes during the immediate postoperative period. Gains were often lost with further follow-up. Progression of radiation maculopathy was primarily responsible for subsequent visual decline.

Cataract surgery after proton-beam irradiation for uveal tumors

PURPOSE

To study the risks associated with cataract surgery in patients with previous proton-beam irradiation (PBI), focusing on preoperative risk factors, intraoperative findings, and postoperative complications.

SETTING

Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA.

DESIGN

Retrospective case series.

METHODS

Electronic medical records of patients who had PBI and cataract surgery between January 1, 2006, and October 1, 2016, were reviewed.

RESULTS

The study comprised 29 eyes of 29 patients. Preoperative evaluation found dry eye (72.4%), posterior synechiae (24.1%), peripheral anterior synechiae (13.8%), anterior capsule fibrosis (10.3%), and iris atrophy (10.3%). Intraoperative findings included poor red reflex requiring trypan blue capsule staining (37.9%), synechiae requiring synechialysis (24.1%), evidence of previous inflammation prompting sub-Tenon triamcinolone injection (17.2%), and miosis (10.3%). Postoperative complications included posterior capsule opacification (PCO) by 1 year (48.3%), intraocular pressure spike of 23 mm Hg or greater at 1 day (24.1%), anterior chamber inflammation at 1 month (24.1%), and cystoid macular edema (CME) (17.2%). Proximity of the initial tumor to the posterior pole was associated with poor visual outcomes after cataract surgery. Compared with reference data, this cohort had higher rates of anterior chamber inflammation at 1 month, CME, fibrinous inflammation, PCO by 1 year, intraoperative requirement for trypan blue, and synechialysis.

CONCLUSIONS

Complications after cataract surgery performed after PBI were similar to those seen in patients with uveitis (prolonged inflammation, CME, fibrinous inflammation, early PCO). Steroid depot administration might be useful to prevent these complications, although further research is needed to determine an optimum regimen.

Brachytherapy and anterior segment imaging in iris melanoma

A 40-year-old male presented to the ophthalmology clinic with a darkly pigmented infratemporal lesion in his right eye. The corrected visual acuity in both eyes was 6/6 and both pupils were equal and reactive. Slit lamp biomicroscopy showed a well-demarcated and heavily pigmented lesion in the peripheral iris between 6 and 8 o’clock. Ultrasound biomicroscopy (UBM) revealed a solid mass deriving from the iris stroma without ciliary body involvement, helping to classify the uveal melanoma and establishing the diagnosis of iris melanoma. Fine needle aspiration (FNA) confirmed melanoma with inactivation of the BAP1 gene. The patient was treated with brachytherapy using an I-125 plaque. Follow-up UBM, three years later, demonstrated significantly reduced dimensions of the tumour. UBM has become crucial to the differentiation of uveal melanomas from benign growths, and lesions <3 mm cannot be reliably visualised by other imaging modalities or localised to the correct uveal structure. Brachytherapy represents a safe and effective treatment option even in lesions that are BAP1 positive.

Results in Combined Cataract Surgery With Prosthetic Iris Implantation in Patients With Previous Iridocyclectomy for Iris Melanoma

PURPOSE

To present visual and functional results following implantation of iris prosthesis combined with cataract surgery in eyes with previous iridocyclectomy for iris melanoma or presumed iris melanoma.

DESIGN

Retrospective noncomparative case series.

METHODS

Sixteen patients (16 eyes) with iris defects after iridocyclectomy for iris melanoma in 15 cases and iris adenoma in 1 case underwent prosthetic iris device implantation surgery. Prosthetic iris implantation was combined with phacoemulsification and intraocular lens (IOL) implantation. The visual acuity, subjective glare and photophobia reduction, anatomic outcome, and complications were reviewed.

RESULTS

Best-corrected visual acuity was improved in 13 eyes (81.25%), remained stable in 2 eyes (12.25%), and decreased in 1 eye (6.25%). Photophobia and glare improved in every case except for 1 (93.75%). Notably, after surgery 12 patients (75.00%) reported no photophobia and 10 patients (62.50%) reported no glare. The median postoperative follow-up was 29.5 months, with a minimum of 5 months and a maximum of 189 months. All iris devices were in the correct position, and all eyes achieved the desired anatomic result. The IOL optic edges were covered in all areas by either residual iris or opaque portions of a prosthetic iris device.

CONCLUSIONS

In patients who have undergone previous iridocyclectomy for presumed iris melanoma, combined cataract surgery and iris prosthesis placement, with or without iris reconstruction, can lead to visual improvement as well as reduction of both glare and photophobia.

Visual Acuity, Contrast Sensitivity and Color Vision Three Years After Iodine-125 Brachytherapy for Choroidal and Ciliary Body Melanoma

PURPOSE

To report visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after iodine-125 brachytherapy for choroidal and ciliary body melanoma (CCM).

DESIGN

Prospective interventional case series.

PARTICIPANTS

Thirty-seven patients (37 eyes) with CCM.

METHODS

Patients had best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, Pelli-Robson contrast sensitivity and Hardy-Rand-Rittler color vision measurement; comprehensive ophthalmology examination; optical coherence tomography; and ultrasonography at baseline prior to, 1 year after, 2 years after and 3 years after I-125 brachytherapy.

MAIN OUTCOME MEASURES

Visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after brachytherapy.

RESULTS

Nineteen (19) men and 18 women with mean age of 58 years (SD 13, range 30-78) prior to, 1 year after, 2 years after and 3 years after brachytherapy had mean best-corrected visual acuity of 77 letters (20/32), 65 letters (20/50), 56 letters (20/80) and 47 letters (20/125); contrast sensitivity of 30, 26, 22 and 19 letters; color vision of 26, 20, 17 and 14 test figures, respectively. Decrease in visual acuity, contrast sensitivity and color vision was statistically significant from baseline at 1 year, 2 years, and 3 years after brachytherapy. Decreased acuity at 3 years was associated with mid-choroid and macula melanoma location, ≥ 4.1 mm melanoma height, radiation maculopathy and radiation optic neuropathy.

CONCLUSION

1, 2 and 3 years after brachytherapy, eyes with CCM had significantly decreased visual acuity, contrast sensitivity and color vision.

Disease control and toxicity outcomes using ruthenium eye plaque brachytherapy in the treatment of uveal melanoma

PURPOSE

Ruthenium-106 ((106)Ru) eye plaques have the potential to achieve excellent tumor control with acceptable radiation toxicity. We evaluated our experience in the management of uveal melanoma treated with (106)Ru brachytherapy.

METHODS AND MATERIALS

The records of 40 patients with uveal melanoma treated with brachytherapy using (106)Ru plaques from 2003 to 2007 at University of Texas MD Anderson Cancer Center were reviewed. Endpoints assessed included tumor control and toxicity.

RESULTS

Median ophthalmologic follow-up was 67 months. Actuarial 5-year rates of local control (LC), progression-free survival (PFS), and overall survival (OS) were 97%, 94%, and 92%. There were 3 deaths, 2 related to melanoma. Fifteen patients experienced clinically significant visual loss; no patients were diagnosed with neovascular glaucoma, and 1 patient developed a clinically significant radiation-associated cataract. No patient required enucleation.

CONCLUSIONS

We report the largest published US cohort of patients treated with (106)Ru plaque brachytherapy for uveal melanoma. Tumor control was excellent, and toxicity was acceptably low. These data support the reintroduction of (106)Ru into clinical practice for ocular melanoma.

Irreversible electroporation of human primary uveal melanoma in enucleated eyes

Uveal melanoma (UM) is the most common primary intraocular tumor in adults and is characterized by high rates of metastatic disease. Although brachytherapy is the most common globe-sparing treatment option for small- and medium-sized tumors, the treatment is associated with severe adverse reactions and does not lead to increased survival rates as compared to enucleation. The use of irreversible electroporation (IRE) for tumor ablation has potential advantages in the treatment of tumors in complex organs such as the eye. Following previous theoretical work, herein we evaluate the use of IRE for uveal tumor ablation in human ex vivo eye model. Enucleated eyes of patients with uveal melanoma were treated with short electric pulses (50–100 µs, 1000–2000 V/cm) using a customized electrode design. Tumor bioimpedance was measured before and after treatment and was followed by histopathological evaluation. We found that IRE caused tumor ablation characterized by cell membrane disruption while sparing the non-cellular sclera. Membrane disruption and loss of cellular capacitance were also associated with significant reduction in total tumor impedance and loss of impedance frequency dependence. The effect was more pronounced near the pulsing electrodes and was dependent on time from treatment to fixation. Future studies should further evaluate the potential of IRE as an alternative method of uveal melanoma treatment.

Current and emerging treatment options for uveal melanoma

Uveal melanoma (UM) is the most common primary malignant intraocular tumor in adults, with a 10-year cumulative metastatic rate of 34%. The most common site of metastasis is the liver (95%). Unfortunately, the current treatment of metastatic UM is limited by the lack of effective systemic therapy. Options for the management of the primary intraocular tumor include radical surgery as well as conservative treatments in order to preserve visual acuity. For metastatic disease, several approaches have been described with no standard method. Nevertheless, median survival after liver metastasis is poor, being around 4–6 months, with a 1-year survival of 10%–15%. In this review, the authors summarize current and promising new treatments for UM.

[Choroidal melanoma treated by protontherapy: anatomical and functional results at Strasbourg University Medical Center]

PURPOSE

To report anatomical and functional results of choroidal melanoma treated by protontherapy between 2001 and 2011 and to compare these with data reported in the literature.

METHODS

The present study is a retrospective review of the charts of patients presenting with choroidal melanoma, managed at Strasbourg University Medical Center between 2001 and 2011, and receiving protontherapy. Visual acuity and a complete ophthalmologic examination, including intraocular pressure, dilated fundus exam, and ultrasonography with measurement of the major diameter of the tumor, were performed prior to treatment and at various follow-up visits (every six months for five years, then once a year for ten years). The rates and timing of local complications (cataract, rubeosis, retinal detachment, neovascular glaucoma and secondary enucleation) and systemic complications (metastasis) are also reported.

RESULTS

Seventy charts were included. Mean age of the treated population was 61.4 ± 15.2 years. Male/female ratio was 1.06. Mean visual acuity, 0.55 ± 0.6 (20/67) on presentation, decreased progressively from month 42. Mean tumor thickness was 5.8 ± 2.8mm and major diameter 11.2 ± 2.9 mm. Decreased tumor thickness was noted beginning at month 12 of follow-up (Anova, P<0.0001), while major diameter remained unchanged over time (P>0.05). The risk of complications (retinal detachment, rubeosis, neovascular glaucoma) was greater between the second and third year. Mean 5-year survival was 87.5%. The rate of secondary enucleation was 8.5%.

CONCLUSION

Protontherapy most often allows for preservation of the globe. Visual loss, often significant and permanent, is frequent.

Palladium-103 radiation therapy for small choroidal melanoma

PURPOSE

To evaluate outcomes after ophthalmic plaque radiation therapy for small choroidal melanomas.

DESIGN

Retrospective study, case series.

PARTICIPANTS

Seventy-two patients with choroidal melanomas ≥1.5 and ≤2.4 mm apical height and ≤10 mm width treated between 2002 and 2012, with a minimum follow-up of 8 months.

METHODS

All patients were treated with palladium-103 plaque brachytherapy. Mean radiation dose to the tumor apex was 82.4 Gy (range, 70.0-102 Gy).

MAIN OUTCOME MEASURES

Local control, radiation complications, visual acuity, and metastatic rate.

RESULTS

Plaque radiotherapy provided 100% local tumor control and eye retention at a mean 54 months of observation (95% confidence interval, 46-63 months). The most common long-term brachytherapy-related complications were radiation maculopathy (43.1%) and radiation optic neuropathy (20.8%) developing at a mean of 27 months (range, 9-72 months) after irradiation. In this series, 94.4% of patients maintained 20/200 or better vision. There has been no small choroidal melanoma-related metastasis.

CONCLUSIONS

Palladium-103 plaque radiation therapy offered excellent local control and visual acuity outcomes for patients with small choroidal melanoma.

Effects of radiotherapy on uveal melanomas and adjacent tissues

Most uveal melanomas are treated with radiotherapy. An adequate understanding of the effects of radiation on the tumour and the healthy ocular tissues is necessary. Ionizing radiation damages cell membranes, organelles, and DNA. Irradiated cells are lysed or undergo apoptosis, necrosis, and senescence. These effects occur in tumour cells and vascular endothelial cells, resulting in tumour shrinkage, ischaemia, infarction, exudation, and fibrosis, which can cause exudative maculopathy, serous retinal detachment, rubeosis, and neovascular glaucoma (ie, 'toxic tumour syndrome'). Such abnormalities must be distinguished from collateral damage to healthy ocular tissues that receive high doses of radiation, and these include radiation-induced retinopathy, optic neuropathy, choroidopathy, cataract, and scleral necrosis. Radiation retinopathy can be treated effectively with photodynamic therapy, anti-angiogenic agents, and intravitreal steroid injections. In some patients, optic neuropathy may improve with intravitreal steroids or anti-angiogenic agents. Neovascular glaucoma resolves with intra-cameral bevacizumab. Exudative retinal detachment can regress with intra-vitreal steroid injections. Cataract is treated in the usual manner. Scleral necrosis, if severe, may require grafting, possibly using a lamellar flap from the same eye. Depending on the bulk of the residual toxic tumour, treatment can consist of intra-vitreal steroids and/or anti-angiogenic agents, transpupillary thermotherapy or photodynamic therapy to the tumour, or surgical removal of the tumour by endo- or exo-resection. Measures aimed at preventing collateral damage include eccentric placement of ruthenium plaques or iodine seeds and delivery of a notched proton beam. The decision to treat a uveal melanoma with radiotherapy requires the ability to manage iatrogenic side effects and complications.

Collaborative ocular melanoma study randomized trial of I-125 brachytherapy

BACKGROUND

Although findings from observational studies published in the 1970s and early 1980s suggested that length of remaining life after a diagnosis of uveal melanoma was similar following enucleation (removal of the eye) and local eye-conserving radiotherapy, the majority of ophthalmologists in the United States were not convinced that "saving the eye" would not compromise survival.

PURPOSE

The Collaborative Ocular Melanoma Study (COMS) was designed to compare enucleation and radiotherapy among similar patients with respect to survival outcomes.

METHODS

A multicenter randomized trial of primary treatment with iodine-125 brachytherapy versus enucleation (i.e., a comparative effectiveness trial) was conducted to provide the evidence required to answer the concerns of ophthalmologists and their patients. Eligibility criteria adopted for the trial were intended to apply to the majority of patients diagnosed with choroidal melanoma who would be suitable candidates for either form of primary treatment.

RESULTS

Accrual to this COMS trial began in 1986 and ended in 1998. Participating patients were followed for 5 to 15 years, depending upon date of enrollment, before all clinical follow-up ended in 2003. No difference in survival outcomes and little difference in quality-of-life outcomes were observed between patients in the brachytherapy arm and those in the enucleation arm. Five-year survival was substantially better than anticipated based on a review of the literature when the trial was designed.

LIMITATIONS

The choice of brachytherapy for delivery of radiation to the tumor had important advantages but also imposed restrictions regarding eligibility.

CONCLUSIONS

The multidisciplinary COMS Group not only successfully conducted a randomized trial that answered the primary study questions but also has contributed to clinical and epidemiologic knowledge of choroidal melanoma through numerous publications. As a consequence of the COMS, a standard approach to I-125 brachytherapy for treatment of choroidal melanoma became widely available to affected patients.

Epidemiological studies of cataract risk at low to moderate radiation doses: (not) seeing is believing

The prevailing belief for some decades has been that human radiation-related cataract occurs only after relatively high doses; for instance, the ICRP estimates that brief exposures of at least 0.5-2 Sv are required to cause detectable lens opacities and 5 Sv for vision-impairing cataracts. For protracted exposures, the ICRP estimates the corresponding dose thresholds as 5 Sv and 8 Sv, respectively. However, several studies, especially in the last decade, indicate that radiation-associated opacities occur at much lower doses. Several studies suggest that medical or environmental radiation exposure to the lens confers risk of opacities at doses well under 1 Sv. Among Japanese A-bomb survivors, risks for cataracts necessitating lens surgery were seen at doses under 1 Gy. The confidence interval on the A-bomb dose threshold for cataract surgery prevalence indicated that the data are compatible with a dose threshold ranging from none up to only 0.8 Gy, similar to the dose threshold for minor opacities seen among Chernobyl clean-up workers with primarily protracted exposures. Findings from various studies indicate that radiation risk estimates are probably not due to confounding by other cataract risk factors and that risk is seen after both childhood and adult exposures. The recent data are instigating reassessments of guidelines by various radiation protection bodies regarding permissible levels of radiation to the eye. Among the future epidemiological research directions, the most important research need is for adequate studies of vision-impairing cataract after protracted radiation exposure.

Risk of cataract extraction among adult retinoblastoma survivors

OBJECTIVE

To investigate the risk of cataract extraction among adult retinoblastoma survivors.

DESIGN

A retrospective cohort study was performed on retinoblastoma survivors who received the diagnosis from 1914 to 1984 and were interviewed in 2000. Lens doses were estimated from radiotherapy records. The cumulative time interval to cataract extraction between dose groups was compared using the log-rank test and Cox regression.

RESULTS

Seven hundred fifty-three subjects (828 eyes) were available for analysis for an average of 32 years of follow-up. During this period, 51 cataract extractions were reported. One extraction was reported in an eye with no radiotherapy compared with 36 extractions in 306 eyes with 1 course of radiotherapy and 14 among 38 eyes with 2 or 3 treatments. The average time interval to cataract extraction in irradiated eyes was 51 years (95% confidence interval [CI], 48-54) following 1 treatment and 32 years (95% CI, 27-37) after 2 or 3 treatments. Eyes exposed to a therapeutic radiation dose of 5 Gy or more had a 6-fold increased risk (95% CI, 1.3-27.2) of cataract extraction compared with eyes exposed to 2.5 Gy or less.

CONCLUSIONS

The results emphasize the importance of ophthalmologic examination of retinoblastoma survivors who have undergone radiotherapy. The risk of cataract extraction in untreated eyes with retinoblastoma is comparable with the risk of the general population.

Treated choroidal melanoma with late metastases to the contralateral orbit

Choroidal melanoma is the commonest adult primary intraocular tumour,1 and usual sites of secondary spread are to liver, bone and lung. Although delayed recurrence of ipsilateral orbital melanoma is well documented, metastasis to the contralateral orbit is a rarely encountered phenomenon. We describe a case of metastatic spread to the contralateral orbit in a patient 12 years after proton beam radiotherapy of choroidal melanoma.

Estrogen protects against radiation-induced cataractogenesis

Cataractogenesis is a complication of radiotherapy when the eye is included in the treatment field. Low doses of densely ionizing space radiation may also result in an increased risk of cataracts in astronauts. We previously reported that estrogen (17-beta-estradiol), when administered to ovariectomized rats commencing 1 week before gamma irradiation of the eye and continuously thereafter, results in a significant increase in the rate and incidence of cataract formation and a decreased latent period compared to an ovariectomized control group. We therefore concluded that estrogen accelerates progression of radiation-induced opacification. We now show that estrogen, if administered continuously, but commencing after irradiation, protects against radiation cataractogenesis. Both the rate of progression and incidence of cataracts were greatly reduced in ovariectomized rats that received estrogen treatment after irradiation compared to ovariectomized rats. As in our previous study, estradiol administered 1 week prior to irradiation at the time of ovariectomy and throughout the period of observation produced an enhanced rate of cataract progression. Estrogen administered for only 1 week prior to irradiation had no effect on the rate of progression but resulted in a slight reduction in the incidence. We conclude that estrogen may enhance or protect against radiation cataractogenesis, depending on when it is administered relative to the time of irradiation, and may differentially modulate the initiation and progression phases of cataractogenesis. These data have important implications for astronauts and radiotherapy patients.