Risk factors for radiation maculopathy after ophthalmic plaque radiation for choroidal melanoma

Generation and comparison of 3D dosimetric reference datasets for COMS eye plaque brachytherapy using model-based dose calculations

PURPOSE

A joint Working Group of the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) was created to aid in the transition from the AAPM TG-43 dose calculation formalism, the current standard, to model-based dose calculations. This work establishes the first test cases for low-energy photon-emitting brachytherapy using model-based dose calculation algorithms (MBDCAs).

ACQUISITION AND VALIDATION METHODS

Five test cases are developed: (1) a single model 6711 125 I brachytherapy seed in water, 13 seeds (2) individually and (3) in combination in water, (4) the full Collaborative Ocular Melanoma Study (COMS) 16 mm eye plaque in water, and (5) the full plaque in a realistic eye phantom. Calculations are done with four Monte Carlo (MC) codes and a research version of a commercial treatment planning system (TPS). For all test cases, local agreement of MC codes was within ∼2.5% and global agreement was ∼2% (4% for test case 5). MC agreement was within expected uncertainties. Local agreement of TPS with MC was within 5% for test case 1 and ∼20% for test cases 4 and 5, and global agreement was within 0.4% for test case 1 and 10% for test cases 4 and 5.

DATA FORMAT AND USAGE NOTES

Dose distributions for each set of MC and TPS calculations are available online (https://doi.org/10.52519/00005) along with input files and all other information necessary to repeat the calculations.

POTENTIAL APPLICATIONS

These data can be used to support commissioning of MBDCAs for low-energy brachytherapy as recommended by TGs 186 and 221 and AAPM Report 372. This work additionally lays out a sample framework for the development of test cases that can be extended to other applications beyond eye plaque brachytherapy.

Radiation-induced ophthalmic risks of long duration spaceflight: Current investigations and interventions

PURPOSE

As the average duration of space missions increases, astronauts will experience longer periods of exposure to risks of long duration space flight including microgravity and radiation. The risks from long-term exposure to space radiation remains ill-defined. We review the current literature on the possible and known risks of radiation on the eye (including radiation retinopathy) after long duration spaceflight.

METHODS

A PubMed and Google Scholar search of the English language ophthalmic literature was performed from inception to July 11, 2022. The following search terms were utilized independently or in conjunction to build this manuscript: "Radiation Retinopathy", "Spaceflight", "Space Radiation", "Spaceflight Associated Neuro-Ocular Syndrome", "Microgravity", "Hypercapnia", "Radiation Shield", "Cataract", and "SANS". A concise and selective approach of references was conducted in including relevant original studies and reviews.

RESULTS

A total of 65 papers were reviewed and 47 papers were included in our review.

CONCLUSION

We discuss the potential and developing countermeasures to mitigate these radiation risks in preparation for future space exploration. Given the complex nature of space radiation, no single approach will fully reduce the risks of developing radiation maculopathy in long-duration spaceflight. Understanding and appropriately overcoming the risks of space radiation is key to becoming a multi-planetary species.

Efficacy of Prophylactic Anti-VEGF in Preventing Radiation Retinopathy: A Systematic Review and Meta-Analysis

Background

In patients predisposed to radiation retinopathy (RR), administration of therapy after apparent clinical signs and symptoms are considered too late, resulting in substantial vision loss and blindness. Early initiation of anti-vascular endothelial growth factor (anti-VEGF) might serve as a strategy to slow disease progression and prolong good eyesight.

Objective

To evaluate the efficacy of prophylactic anti-VEGF in preventing RR and preserving vision in patients at high risk of radiation-induced vision loss.

Methods

A systematic literature search was performed from inception to 4 June 2023 using Cochrane Library, EMBASE, PubMed (MEDLINE), and Scopus. Eligible studies were clinical trials and observational studies investigating the incidence of radiation maculopathy (RM), radiation optic neuropathy (RON), moderate vision loss (loss of more than or equal to 3 lines of baseline visual acuity [VA]) and final VA, whether good (20/40 or better) or poor (20/200 or worse), following prophylactic anti-VEGF. Three reviewers independently conducted article screening, data extraction and risk of bias assessment. Random effects models were used to determine the cumulative effects of each outcome.

Results

Four studies (one clinical trial and three observational studies), involving 2109 patients, were included in our analysis. Across all studies, there were significant reductions in the events of RM (pooled odds ratio [OR] 0.50; 95% CI, 0.34-0.74; p = 0.001), RON (pooled OR 0.62; 95% CI, 0.42-0.90; p = 0.012) and poor final VA (pooled OR 0.50; 95% CI, 0.37-0.68; p = 0.003). The association of moderate vision loss and good final VA with the use of prophylactic anti-VEGF between the groups was unclear owing to the high level of heterogeneity.

Conclusion

Prophylactic anti-VEGF therapy might delay RM and RON, preventing high-risk patients from developing poor VA by approximately 50%. However, this evidence should be interpreted with caution because of its low level of certainty. Future robust studies are warranted to confirm this finding.

Laser treatment for choroidal melanoma: Current concepts

Laser treatment has offered a relatively nonsurgical alternative for eye, life, and vision-sparing treatment of malignant melanoma of the choroid. Historically, the most commonly used forms of lasers were xenon-arc, argon laser, krypton laser, and the more recent transpupillary thermotherapy (TTT) and photodynamic therapy (PDT). Melanomas selected for laser treatment tend to be smaller and visibly accessible, which means these tumors are usually located in the posterior choroid. Laser treatments have been associated with both local tumor destruction and side effects. Unlike radiation therapy, laser treatment has been commonly associated with retinal traction, hemorrhage, chorioretinal neovascularization, and extra scleral tumor extension, as well as higher rates of local treatment failure. In addition, however, laser-treatment has been successfully used to treat tumor-related retinal detachments, radiation retinopathy, and neovascular glaucoma. We review the world's experience of ophthalmic laser treatment for choroidal melanoma, offer safety and efficacy guidelines, as well as a comparison of laser treatment to radiation therapy outcomes.

A Systematic Comparison of Dose Distributions Delivered in 125I Plaque Brachytherapy and Proton Radiation Therapy for Ocular Melanoma

PURPOSE

To characterize dose distributions with ¹²⁵I plaque brachytherapy compared with proton radiation therapy for ocular melanoma for relevant clinical scenarios, based on tumor base diameter (d), apical height (h), and location.

METHODS AND MATERIALS

Plaque and proton treatment plans were created for 4 groups of cases: (1) REF: 39 instances of reference midsize circular-base tumor (d = 12 mm, h = 5 mm), in locations varying by retinal clock hours and distance to fovea, optic disc, and corneal limbus; (2) SUP: 25 superiorly located; (3) TEMP: 25 temporal; and (4) NAS: 25 nasally located tumors that were a fixed distance from the fovea but varying in d (6-18 mm) and h (3-11 mm). For both modalities, 111 unique scenarios were characterized in terms of the distance to points of interest, doses delivered to fovea, optic disc, optic nerve at 3 mm posterior to the disc (ON@3mm), lens, and retina. Comparative statistical evaluation was performed with the Mann-Whitney U test.

RESULTS

Superior dose distributions favored plaque for sparing of (1) fovea in large (d + h ≥ 21 mm) NAS tumors; (2) ON@3mm in REF cases located ≤4 disc diameters from disc, and in NAS overall. Protons achieved superior dose sparing of (1) fovea and optic disc in REF, SUP, and TEMP; (2) ON@3mm in REF >4 disc diameters from disc, and in SUP and TEMP; and (3) the lens center overall and lens periphery in REF ≤6 mm from the corneal limbus, and in TEMP with h = 3 mm. Although protons could completely spare sections of the retina, plaque dose was more target conformal in the high-dose range (50% and 90% of prescription dose).

CONCLUSIONS

Although comparison between plaque and proton therapy is not straightforward because of the disparity in dose rate, prescriptions, applicators, and delivery techniques, it is possible to identify distinctions between dose distributions, which could help inform decisions by providers and patients.

Early anti-VEGF treatment for radiation maculopathy and optic neuropathy: lessons learned

Radiation therapy has saved both sight and life for eye cancer patients. The most common methods include ophthalmic plaque brachytherapy and external beam techniques. However, subsequent dose-dependent radiation vasculopathy invariably occurs within and around the targeted zone. In 2006, Finger discovered that periodic intravitreal anti-vascular endothelial growth factor (anti-VEGF) bevacizumab could reverse and suppress intraocular radiation vasculopathy. At first, it was administered at the onset of radiation-related vision loss. Though bevacizumab induced regression of macular oedema, retinal haemorrhages and cotton-wool infarcts, most patients were left with residual retinal damage, manifest as metamorphopsia and loss of vision. These results led to earlier and earlier anti-VEGF interventions: first after signs of progressive radiation retinopathy, and then for signs of radiation maculopathy, and finally for high-risk eyes with no clinical signs of retinopathy. Earlier initiation of intravitreal anti-VEGF therapy typically resulted in greater restoration and preservation of macular anatomy, reductions of retinal haemorrhages, resolution of cotton-wool spots and vision preservation. Recent research on optical coherence tomography angiography (OCT-A) has revealed that radiation vasculopathy occurs prior to clinical ophthalmic signs or symptoms. Therefore, it seemed reasonable to consider treating high-risk patients (considered certain to eventually develop radiation maculopathy) to prevent or delay vision loss. Herein, we describe the evolution of treatment for radiation maculopathy as well as recent research supporting anti-VEGF treatment of high-risk patients immediately following radiation to maximize vision outcomes.

Local tumor control and treatment related toxicity after plaque brachytherapy for uveal melanoma: A systematic review and a data pooled analysis

Uveal melanoma (UM) represents the most common primary intraocular tumor, and nowadays eye plaque brachytherapy (EPB) is the most frequently used visual acuity preservation treatment option for small to medium sized UMs. The excellent local tumor control (LTC) rate achieved by EPB may be associated with severe complications and adverse events. Several dosimetric and clinical risk factors for the development of EPB-related ocular morbidity can be identified. However, morbidity predictive models specifically developed for EPB are still scarce. PRISMA methodology was used for the present systematic review of articles indexed in PubMed in the last sixteen years on EPB treatment of UM which aims at determining the major factors affecting local tumor control and ocular morbidities. To our knowledge, for the first time in EPB field, local tumor control probability (TCP) and normal tissue complication probability (NTCP) modelling on pooled clinical outcomes were performed. The analyzed literature (103 studies including 21,263 UM patients) pointed out that Ru-106 EPB provided high local control outcomes while minimizing radiation induced complications. The use of treatment planning systems (TPS) was the most influencing factor for EPB outcomes such as metastasis occurrence, enucleation, and disease specific survival, irrespective of radioactive implant type. TCP and NTCP parameters were successfully extracted for 5-year LTC, cataract and optic neuropathy. In future studies, more consistent recordings of ocular morbidities along with accurate estimation of doses through routine use of TPS are needed to expand and improve the robustness of toxicity risk prediction in EPB.

Comparison of iodine-125 plaque brachytherapy and gamma knife stereotactic radiosurgery treatment outcomes for uveal melanoma patients

PURPOSE

To compare the efficacies of iodine-125 brachytherapy (IBT) and gamma knife stereotactic radiosurgery (GKRS) in the treatment of posterior uveal melanoma.

METHODS

The demographic data and tumor characteristics at diagnosis of 201 patients treated with IBT and 52 patients treated with GKRS were recorded. The two treatments were then compared in terms of complications, local control, eye retention, metastasis, and overall survival rate.

RESULTS

The median follow-up time was 56 months for the GKRS group and 45 months for the IBT group (p = 0.167). There were no significant differences in demographic data or tumor characteristics between the groups at diagnosis. Radiation retinopathy, radiation optic neuropathy, and neovascular glaucoma occurred at similar rates in both groups. However, radiation maculopathy and cataracts occurred more frequently in the GKRS group. The number of cases that have developed vision loss (worsening of best-corrected visual acuity on three or more lines on the Snellen chart) was significantly higher in the GKRS group (60%) compared to the IBT group (44%) (p = 0.048). Local control, metastasis, and 5-year overall survival rates were statistically similar in both groups.

CONCLUSIONS

GKRS can be preferred as an eye-sparing treatment option for posterior uveal melanoma in cases where brachytherapy cannot be used.

Randomized Trial of Monthly Versus As-Needed Intravitreal Ranibizumab for Radiation Retinopathy-Related Macular Edema: 1-Year Outcomes

PURPOSE

To assess efficacy of intravitreal ranibizumab injections and targeted panretinal photocoagulation (TRP) for radiation retinopathy-related macular edema.

DESIGN

Phase IIb, prospective, randomized clinical trial.

METHODS

Setting: Multicenter.

SUBJECTS

Forty eyes in 40 treatment-naïve patients with radiation-induced macular edema and a resulting decrease in visual acuity ranging between 20/25 and 20/400 (Snellen equivalent).

INTERVENTION

Patients either received intravitreal 0.5 mg ranibizumab monthly, monthly ranibizumab with TRP, or 3 monthly ranibizumab (loading doses) followed by as-needed (PRN) injections and TRP. After week 52, all subjects entered a treat-and-extend protocol for ranibizumab. MainOutcomeMeasures: Mean Early Treatment Diabetic Maculopathy Study (ETDRS) BCVA change from baseline.

RESULTS

Mean patient age was 57 years (range, 22-80 years), ETDRS BCVA was 56.7 letters (20/74 Snellen equivalent), and central macular thickness (CMT) was 423 μm (range, 183-826 μm). Thirty-seven patients completed the month 12 visit (92.5%), at which time the change in mean BCVA was +4.0 letters, -1.9 letters, and +0.9 letters in the monthly, monthly plus laser, and PRN plus laser cohorts, respectively. There was a significant difference in mean BCVA at 1 year among all 3 cohorts (P < .001), as well as between cohorts in pairwise comparisons, with the most significant gains in the monthly group. A total of 82.5% of the patients retained visual acuity of 20/200 or better, and 20.0% improved 10 or more ETDRS letters.

CONCLUSIONS

Ranibizumab may improve vision and anatomy in patients with radiation retinopathy-related macular edema and prevent vision loss through 48 weeks of therapy. Monthly injections were more effective than as-needed approach, and the addition of TRP yielded no therapeutic benefits.

Predicting Visual Acuity Deterioration and Radiation-Induced Toxicities after Brachytherapy for Choroidal Melanomas

Ruthenium-106 (Ru-106) brachytherapy is an established modality for eye-preserving treatment of choroidal melanoma. To achieve optimal treatment outcomes, there should be a balance between tumour control and the risk of healthy tissue toxicity. In this retrospective study, we examined normal tissue complication probability (NTCP) for visual acuity deterioration and late complications to aid the understanding of dose-dependence after Ru-106 treatments. We considered consecutive patients diagnosed with choroidal melanoma and primarily treated at a single institution from 2005-2014. Treatment plans were retrospectively recreated using dedicated software and image guidance to contour the tumour and determine the actual plaque position. Dose distributions were extracted from each plan for all relevant anatomical structures. We considered visual acuity deterioration and late complications (maculopathy, optic neuropathy, ocular hypertension, vascular obliteration, cataract and retinal detachment). Lasso statistics were used to select the most important variables for each analysis. Outcomes were related to dose and clinical characteristics using multivariate Cox regressions analysis. In total, 227 patients were considered and 226 of those were eligible for analysis. Median potential follow-up time was 5.0 years (95% CI: 4.5-6.0). Visual acuity deterioration was related to optic disc-tumour distance and dose metrics from the retina and the macula, with retina V10Gy showing the strongest correlation. Macula V10Gy was the only dose metric impacting risk of maculopathy, while optic disc-tumour distance also proved important. Optic disc V50Gy had the largest impact on optic neuropathy along with optic disc-tumour distance. Optic disc V20Gy was the only variable associated with vascular obliteration. Lens D2% had the largest impact on the risk of cataract along with older age and the largest base dimension. We found no variables associated with the risk of ocular hypertension and retinal detachment. Visual acuity deterioration and most late complications demonstrated dependence on dose delivered to healthy structures in the eye after Ru-106 brachytherapy for choroidal melanomas.

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.

Retinal crystalline deposits in a patient who received chemotherapy and radiotherapy for nasopharyngeal carcinoma and subsequent anti-VEGF treatment for the bilateral radiation maculopathy

We report the occurrence of intraretinal crystalline deposits in a patient who received several anti-VEGF injections and one session of focal laser treatment for the treatment of radiation retinopathy during the treatment process. She had received three cycles of epirubicin and cisplatin together with radiation therapy seven years prior to detection of the maculopathy. The multimodal imaging features and the possible cause of the retinal crystalline deposits are discussed.

A comparison of the shielding effectiveness of silicone oil vitreous substitutes when used with Palladium-103 and Iodine-125 eye plaques

PURPOSE

Episcleral eye plaques provide excellent local control of ocular melanoma, but vision sparing remains a significant problem with 30% or more of patients experiencing significant visual acuity degradation. The use of silicone oil shielding with Iodine-125 plaques has previously been reported to improve critical structure sparing. We hypothesized that the use of Palladium-103 would improve the shielding effectiveness of silicone oil due to the strong energy dependence of the photoelectric effect. This Monte Carlo simulation study reports a comparison of the shielding effects of silicone oil when used in conjunction with Pd-103 and with I-125 plaques.

MATERIALS AND METHODS

GEANT4 was used to simulate eye plaque treatments to an eye with either water-equivalent vitreous humor, or silicone oil in place of the vitreous humor. Two solid gold plaques, 15 and 23 mm, were simulated loaded with I-125 and with Pd-103 source seeds. Seed activity was normalized such that 85 Gy was delivered to the tumor apex in the water-equivalent cases. Tumor apex dose, central axis dose, and inner sclera dose reductions with silicone oil were evaluated.

RESULTS

Silicone oil resulted in an underdosing to the tumor apex of 6.1% and 7.5% in the 15 mm plaque for I-125 and Pd-103, respectively, and 3.4% and 4.3% in the 23 mm plaque for I-125 and Pd-103, respectively. When renormalized to 85 Gy to the tumor apex in all scenarios, silicone oil reduced the dose to the inner sclera 90° from the plaque by 19-32% for the 15 and 23 mm plaques using I-125, and by 33-65% for the 15 and 23 mm plaques using Pd-103.

CONCLUSIONS

The combination of silicone oil and Pd-103 eye plaques offers the potential for greatly improved sparing to normal structures compared to Pd-103 plaques alone or I-125 plaques with or without silicone oil.

Enhanced Depth Imaging OCT of Ultrasonographically Flat Choroidal Nevi Demonstrates 5 Distinct Patterns

PURPOSE

To characterize the enhanced depth imaging (EDI) OCT features of ultrasonographically flat choroidal nevi.

DESIGN

Retrospective observational study.

PARTICIPANTS

Patients with ultrasonographically flat choroidal nevi identified over a 3-year period.

METHODS

Comprehensive eye examinations and multimodal imaging were performed every 6 to 12 months.

MAIN OUTCOME MEASURES

Lesion thickness and features, EDI-OCT findings.

RESULTS

A total of 102 nevi (98 patients) were included. Median follow-up was 9 months (range 0-144 months) and 1 to 8 (mean 2.1) OCTs were performed. On OCT, nevi were classified into 5 subtypes: 3.2% were "not visible," 37.2% had "hyperreflectivity confined within normal choroidal thickness," 16.0% had characteristic anteriorly bowed hyperreflectivity with "discrete" borders and cascading edges, 14.9% were "flat with posterior bowing," and 28.7% were "elevated." One nevus of the "elevated" type demonstrated clinically insignificant growth (<10% in thickness) after 22 months of follow-up.

CONCLUSIONS

Five distinct EDI-OCT patterns of choroidal nevi seemed flat on ultrasonography, and many demonstrated thickness and elevation not measurable on B-scan ultrasonography. Lesion thickness can be measured using EDI-OCT.

Outcomes of choroidal melanomas treated with eye physics plaques: A 25-year review

PURPOSE

To review long-term outcomes of the University of Southern California Plaque Simulator (PS) software and Eye Physics (EP) plaques. We hypothesize that the PS/EP system delivers lower doses to critical ocular structures, resulting in lower rates of radiation toxicity and favorable visual outcomes compared to Collaborative Ocular Melanoma Study plaques, while maintaining adequate local tumor control.

METHODS AND MATERIALS

Retrospective review of 133 patients treated for choroidal melanoma with ¹²⁵I brachytherapy, using PS software and EP plaques, from 1990 through 2015. A dose of 85 Gy at a rate of 0.6 Gy/h was prescribed to the tumor apex (with a typical margin of 2 mm) over 7 days. Primary outcomes were local tumor recurrence, globe salvage, and metastasis. Secondary outcomes were changes in visual acuity and radiation complications.

RESULTS

With median followup of 42 months, 5-year Kaplan-Meier estimated rates for tumor control, globe salvage, and metastatic-free survival were 98.3%, 96.4%, and 88.2%, respectively. Median doses to the macula and optic nerve were 39.9 Gy and 30.0 Gy, respectively. Forty-three percent of patients developed radiation retinopathy, and 20% developed optic neuropathy; 39% lost ≥6 Snellen lines of vision.

CONCLUSIONS

The PS/EP system is designed to improve the accuracy and conformality of the radiation dose, creating a steep dose gradient outside the melanoma to decrease radiation to surrounding ocular structures. We report favorable rates of local tumor control, globe salvage, metastases, and radiation complications when compared to the Collaborative Ocular Melanoma Study and other studies. Overall, the PS/EP system results in excellent tumor control and appears to optimize long-term visual and radiation-related outcomes after brachytherapy.

DEXAMETHASONE INTRAVITREAL IMPLANT VS RANIBIZUMAB IN THE TREATMENT OF MACULAR EDEMA SECONDARY TO BRACHYTHERAPY FOR CHOROIDAL MELANOMA

PURPOSE

To evaluate the efficacy of an intravitreal dexamethasone (Dex) implant 0.7 mg compared with intravitreal ranibizumab (Ra) for the treatment of radiation maculopathy with macular edema secondary to plaque brachytherapy in choroidal melanoma.

METHODS

Eight patients were treated with intravitreal Ra, and eight patients received the Dex intravitreal implant. Visual acuity and foveal thickness were evaluated using spectral domain optical coherence tomography.

RESULTS

The mean calculated irradiation to the fovea and mean times from brachytherapy to maculopathy development did not differ significantly between groups. In the Ra group, a mean 7.8 ± 3.9 injections were given and the mean follow-up was 33 ± 15 months (range, 7-52 months). In the Dex group, a mean 2.1 ± 0.8 injections were given and the mean follow-up was 22 ± 7 months (range, 11-31 months). The mean visual acuity improved significantly from the baseline to the last follow-up visit in both groups. Foveal thickness decreased significantly in both groups from 459 ± 81 μm to 243 ± 58 μm and from 437 ± 71 μm to 254 ± 44 μm from the baseline to the last follow-up visit in the Ra and Dex groups, respectively. No patients developed significant cataract or ocular hypertension in both groups.

CONCLUSION

Both Ra and Dex are effective treatments for macular edema secondary to plaque brachytherapy for uveal melanoma. Dex-treated patients required fewer injections to achieve anatomical and functional improvement.

Intravitreal triamcinolone acetate for radiation maculopathy recalcitrant to high-dose intravitreal bevacizumab

BACKGROUND/AIMS

To evaluate the effect of adjuvant intravitreal triamcinolone acetonide (ITA) for radiation maculopathy (RM) recalcitrant to high-dose bevacizumab in patients with choroidal melanoma after plaque radiotherapy.

METHODS

Eight eyes of eight patients with RM secondary to plaque radiotherapy for choroidal melanoma, recalcitrant to high-dose bevacizumab (3.0 mg) were retrospectively evaluated. Intravitreal injections of ITA (4 mg/0.1 mL) were performed at 4-week to 16-week intervals as an adjunct to continued bevacizumab therapy. Change in central foveal thickness (CFT) as measured by optical coherence tomography and change in visual acuity (VA) were the main outcome measures.

RESULTS

At the time of diagnosis of choroidal melanoma, VA was 20/20 to 20/50 in 88% (n=7) and 20/60 to 20/200 in 12% (n=1). The mean radiation dose to the fovea was 81 Gy (median 75.2 Gy; range: 22.72-132.8 Gy). The mean onset to RM was 25 months after plaque therapy (median 25 months; range 12-44 months). At the time of initiation of ITA, VA was 20/20 to 20/50 in 38% (3/8), and 20/60 to 20/200 in 62% (5/8). After initiation of ITA, VA was stable or improved in 100% of patients (n=8) at 3 months, 88% at 6 months, 88% at 9 months and 75% at 12 months. Mean CFT was 417 µm at ITA initiation, 339 µm at 1 month, 355 µm at 6 months, 339 µm at 9 months and 359 µm at 1 year.

CONCLUSION

Intravitreal triamcinolone can be added to preserve vision and decrease macular oedema in patients with RM recalcitrant to high-dose anti-vascular endothelial growth factor agents.

[Diagnostic potential of optical coherence tomography for small choroidal melanomas]

AIM

To investigate the sequence of OCT manifestations in choroidal melanoma (CM) with account to its growth.

MATERIAL AND METHODS

A total of 28 CM patients were examined. Of them, 18 patients with early CM, 10 - with medium-sized CM. The mean patient age at diagnosis was 60.54±5.31 years. Tumor location was macular (15 eyes) or perimacular (13 eyes), its prominence varied from 0.98 to 4.9 mm and basal diameter - from 5.08 to 18.9 mm. Additionally to OCT, tumor autofluorescence was studied in all cases.

RESULTS

The sequence of OCT manifestations in CM has been investigated with account to its growth. Our findings include an early change in choroidal profile with often uneven configuration and a plateau in the most prominent part of the lesion. Along with changes in the retinal pigment epithelium (RPE), one could see signs of an initially local small neuroepithelial detachment (NED) with alterations in the photoreceptor layer. We have identified three types of photoreceptor damage. Destruction of all retinal layers (its morphofunctional disorder) indicates the transition of an early CM to a medium one. As to autofluorescence RESULTS: there were lipofuscin deposits in RPE cells detected in OCT scans that showed an evident hyperautofluorescence. The central part the tumor was notable for its hypoautofluorescence. The periphery of the lesion was hyperautofluorescent due to NED.

CONCLUSION

Qualitative changes in the retina overlying choroidal melanoma develop early in the course of the disease, practically in the moment of the first shift of choroidal profile. Destruction begins with the RPE and neuroepithelium (detachment and structural changes). As the tumor grows, retinal architectonics gets irreversibly distorted: the tissue becomes thicker due to edema, cysts, and intraretinal deposits. This process is, of course, accompanied by changes in metric parameters of all retinal layers and the choroid within the area of interest.

Predictive risk factors for radiation retinopathy and optic neuropathy after proton beam therapy for uveal melanoma

PURPOSE

This study was performed in order to evaluate the incidence of radiation retinopathy and optic neuropathy occurring after proton beam therapy for uveal melanoma.

METHODS

Included in this study were all patients who had been treated with primary proton beam therapy for uveal melanoma at the oncology service between May 1998 and June 2014 with a minimum follow-up of 12 months. Excluded were all patients who underwent re-irradiation, or vitrectomy due to exudative retinal detachment or for tumor-resection.

RESULTS

During this period, 1127 patients matched the inclusion criteria, of whom 768 (68.1 %) and 463 (41.0 %) developed radiation retinopathy and optic neuropathy after a median time of 18.9 months (2.0-99.84 months) and 19.8 months (0.2-170.4 months), respectively. Mean follow-up was 53.4 months (12-170.4 months). Included were 558 men (49.5 %) and 569 women (50.5 %). Mean age was 61 years (16-89 years). Visual acuity slightly decreased from initial levels of 0.3 logMAR-0.4 logMAR in patients without developing any radiation-induced complication but severely decreased to 1.0 logMAR or 1.5 logMAR in the case of developing radiation retinopathy only or optic neuropathy, respectively. Independent risk factors for radiation retinopathy were a centrally (<2.5 mm from sensitive structures) located tumor or a thick tumor located more than 2.5 mm from sensitive structures, while those for radiation optic neuropathy comprised a short distance and applied dose to the optic disk.

CONCLUSION

The risk for radiation retinopathy is higher in central uveal melanoma. Mid-/peripheral tumors are at high risk for radiation retinopathy and maculopathy if presenting with increased thickness.

INTRAVITREAL DEXAMETHASONE IMPLANT FOR RADIATION MACULOPATHY SECONDARY TO PLAQUE BRACHYTHERAPY IN CHOROIDAL MELANOMA

PURPOSE

To evaluate the efficacy of intravitreal dexamethasone implant 0.7 mg (Ozurdex) in radiation maculopathy secondary to plaque brachytherapy in choroidal melanoma.

METHODS

Twelve eyes diagnosed of radiation maculopathy secondary to plaque brachytherapy and treated with intravitreal dexamethasone implant were included. Visual acuity, foveal thickness using spectral domain optical coherence tomography, and grade of macular edema, using Horgan classification, were evaluated.

RESULTS

Mean age was 65.5 ± 28 years (range, 40-82 years). Mean follow-up was 8.2 ± 7.8 months (range, 2-28 months). Mean visual acuity before treatment was, in logarithm of the minimum angle of resolution scale, 1 ± 0.58 (range, 0.4-2) and mean final visual acuity 0.8 ± 0.58 (range, 0.2-2), showing a nonsignificant trend to improvement (P = 0.091; Wilcoxon's test). Foveal thickness before treatment was 416 ± 263 μm (range, 222-725 μm) and final foveal thickness 254 ± 170 μm (range, 145-750), showing a significant decrease (P = 0.016; Wilcoxon's test). Referring to Horgan classification, a significant reduction in grades before and after treatment was demonstrated (P = 0.007; Wilcoxon's test).

CONCLUSION

Ozurdex is a useful treatment for radiation maculopathy associated to plaque brachytherapy for uveal melanoma, with a significant decrease in foveal thickness and a significant improvement in Horgan classification. This anatomical improvement was correlated with a moderate improvement in visual acuity.

Intravitreal anti-VEGF therapy for macular radiation retinopathy: a 10-year study

PURPOSE

To report long-term experience with intravitreal anti-vascular endothelial growth factor treatment for radiation maculopathy.

METHODS

From 2005-2015, 120 consecutive patients underwent intravitreal anti-VEGF therapy for radiation maculopathy. Inclusion criteria included a diagnosis of uveal melanoma treated with plaque radiotherapy and subsequent macular radiation vasculopathy (exudate, retinal hemorrhage, intraretinal microangiopathy, neovascularization, edema). Anti-VEGF therapy involved continuous injections in 4- to 12-week intervals with doses of 1.25 mg/0.05 mL, 2.0 mg/0.08 mL, 2.5 mg/0.1 mL, or 3.0 mg/0.12 mL of bevacizumab as well as 0.5 mg/0.05 mL or 2.0 mg/0.05 mL of ranibizumab. Goals were maintenance of visual acuity and normative macular anatomy. Safety and tolerability (retinal detachment, hemorrhage, infection), visual acuity, central foveal thickness on optical coherence tomography imaging, and clinical features of radiation maculopathy were analyzed.

RESULTS

Progressive reductions in macular edema, hemorrhages, exudates, cotton-wool spots, and microangiopathy were noted. At last follow-up, 80% remained within 2 lines of their initial visual acuity or better, with a mean treatment interval of 38 months (range 6-108 months). Kaplan-Meier analysis of the probability of remaining within 2 lines of initial visual acuity was 69% at 5 years and 38% at 8 years of anti-VEGF therapy. Discontinuation of therapy was rare. Relatively few acute or long-term side effects were noted, allowing for good long-term patient accrual.

CONCLUSIONS

Continuous intravitreal anti-VEGF therapy in patients with radiation maculopathy was well-tolerated and preserved vision. In most cases, reductions or resolution of retinal hemorrhages, cotton-wool spots, and retinal edema were noted for up to 10 years.

Treatment of recalcitrant radiation maculopathy using intravitreal dexamethasone (Ozurdex) implant

PURPOSE

Radiation maculopathy is the most common cause of severe vision loss after radiotherapy of uveal melanoma. To date, no effective therapy exists. The authors report a novel approach to the treatment of radiation maculopathy using dexamethasone (Ozurdex, Allergan Inc) intravitreal implant.

METHODS

This is a retrospective case series of two patients who developed radiation maculopathy after radiotherapy for uveal melanoma and was treated with Ozurdex. Clinical outcomes included visual acuity, central foveal thickness by optical coherence tomography, intraocular pressure, and cataract formation.

RESULTS

Both patients were of Caucasian descent. Patient 1 received charged-particle radiation, whereas Patient 2 received iodine-125 brachytherapy for medium-sized uveal melanoma located in the midperipheral retina. Radiation maculopathy developed 47 months and 18 months after radiation exposure in Patient 1 and 2, respectively. Both patients initially received bevacizumab monotherapy followed by alternating therapy with bevacizumab and intravitreal triamcinolone. Secondary to a limited response, the patients were treated with Ozurdex implants. One patient had visual improvement, and both patients experienced a prolonged time frame of anatomical stability. Adverse effects included a rise in the intraocular pressure, which was controlled by topical hypotensive agents and posterior subcapsular cataract formation in Patient 1.

CONCLUSION

Ozurdex intravitreal implant provides a prolonged period of anatomical stabilization in recalcitrant cases of radiation maculopathy in patients who have failed multiple intravitreal bevacizumab injections and had only a partial response to intravitreal triamcinolone. Larger prospective studies are required to determine the extent of visual benefit.

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.

103Pd versus 125I ophthalmic plaque brachytherapy: preoperative comparative radiation dosimetry for 319 uveal melanomas

Objective

This study was conducted to compare the relative, clinical intraocular dose distribution for palladium-103 (¹⁰³Pd) versus iodine-125 (¹²⁵I) ophthalmic plaque radiation therapy.

Methods

Preoperative comparative radiation dosimetry was performed to evaluate 319 consecutive uveal melanomas treated between 2006 and 2012.

Results

There were 68 (21.3 %) anterior (iris and/or ciliary body) and 251 (78.7 %) choroidal melanomas examined in this study. According to AJCC staging, 7th edition, 146 (45.8 %) were T1, 126 (39.5 %) T2, 40 (12.5 %) T3, and 7 (2.2 %) T4. All were prescribed an equivalent tumor-apex dose. When compared to ¹²⁵I, ¹⁰³Pd was associated with a mean 41.9 % lower radiation dose to the opposite eye wall (p < 0.001), 12.7 % to the lens center (p < 0.001), 7.5 % to the optic disc (p = 0.008), and a 3.8 % decrease to the fovea (p = 0.034). However, subgroup analysis of smaller (T1-staged) tumors showed greater dose reductions to normal ocular structures compared to larger (T4-staged) tumors. Tumor and therefore plaque location also affected intraocular dose distribution. For example, palladium-103-related dose reductions to the fovea, optic nerve, and opposite eye wall were significantly greater for iris and ciliary body tumors compared to posterior choroidal melanomas (p < 0.001). After comparative dosimetry, 98.7 % (n = 315/319) were treated with ¹⁰³Pd.

Conclusion

Preoperative comparative radiation dosimetry was performed for a large cohort of patients with uveal melanoma. It influenced radionuclide selection, offered an opportunity for radiation sparing of critical vision-related intraocular structures, and typically increased radiation within the tumors.

The American Brachytherapy Society consensus guidelines for plaque brachytherapy of uveal melanoma and retinoblastoma

PURPOSE

To present the American Brachytherapy Society (ABS) guidelines for plaque brachytherapy of choroidal melanoma and retinoblastoma.

METHODS AND MATERIALS

An international multicenter Ophthalmic Oncology Task Force (OOTF) was assembled to include 47 radiation oncologists, medical physicists, and ophthalmic oncologists from 10 countries. The ABS-OOTF produced collaborative guidelines, based on their eye cancer-specific clinical experience and knowledge of the literature. This work was reviewed and approved by the ABS Board of Directors as well as within the journal's peer-reivew process.

RESULTS

The ABS-OOTF reached consensus that ophthalmic plaque radiation therapy is best performed in subspecialty brachytherapy centers. Quality assurance, methods of plaque construction, and dosimetry should be consistent with the 2012 joint guidelines of the American Association of Physicists in Medicine and ABS. Implantation of plaque sources should be performed by subspecialty-trained surgeons. Although there exist select restrictions related to tumor size and location, the ABS-OOTF agreed that most melanomas of the iris, ciliary body, and choroid could be treated with plaque brachytherapy. The ABS-OOTF reached consensus that tumors with gross orbital extension and blind painful eyes and those with no light perception vision are unsuitable for brachytherapy. In contrast, only select retinoblastomas are eligible for plaque brachytherapy. Prescription doses, dose rates, treatment durations, and clinical methods are described.

CONCLUSIONS

Plaque brachytherapy is an effective eye and vision-sparing method to treat patients with intraocular tumors. Practitioners are encouraged to use ABS-OOTF guidelines to enhance their practice.

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.

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.

The retina dose-area histogram: a metric for quantitatively comparing rival eye plaque treatment options

PURPOSE

Episcleral plaques have a history of over a half century in the delivery of radiation therapy to intraocular tumors such as choroidal melanoma. Although the tumor control rate is high, vision-impairing complications subsequent to treatment remain an issue. Notable, late complications are radiation retinopathy and maculopathy. The obvious way to reduce the risk of radiation damage to the retina is to conform the prescribed isodose surface to the tumor base and to reduce the dose delivered to the surrounding healthy retina, especially the macula. Using a fusion of fundus photography, ultrasound and CT images, tumor size, shape and location within the eye can be accurately simulated as part of the radiation planning process. In this work an adaptation of the dose-volume histogram (DVH), the retina dose-area histogram (RDAH) is introduced as a metric to help compare rival plaque designs and conformal treatment planning options with the goal of reducing radiation retinopathy.

MATERIAL AND METHODS

The RDAH is calculated by transforming a digitized fundus-photo collage of the tumor into a rasterized polar map of the retinal surface known as a retinal diagram (RD). The perimeter of the tumor base is digitized on the RD and its area computed. Area and radiation dose are calculated for every pixel in the RD.

RESULTS

The areal resolution of the RDAH is a function of the pixel resolution of the raster image used to display the RD and the number of polygon edges used to digitize the perimeter of the tumor base. A practical demonstration is presented.

CONCLUSIONS

The RDAH provides a quantitative metric by which episcleral plaque treatment plan options may be evaluated and compared in order to confirm adequate dosimetric coverage of the tumor and margin, and to help minimize dose to the macula and retina.

Dosimetry of (125)I and (103)Pd COMS eye plaques for intraocular tumors: report of Task Group 129 by the AAPM and ABS

Dosimetry of eye plaques for ocular tumors presents unique challenges in brachytherapy. The challenges in accurate dosimetry are in part related to the steep dose gradient in the tumor and critical structures that are within millimeters of radioactive sources. In most clinical applications, calculations of dose distributions around eye plaques assume a homogenous water medium and full scatter conditions. Recent Monte Carlo (MC)-based eye-plaque dosimetry simulations have demonstrated that the perturbation effects of heterogeneous materials in eye plaques, including the gold-alloy backing and Silastic insert, can be calculated with reasonable accuracy. Even additional levels of complexity introduced through the use of gold foil "seed-guides" and custom-designed plaques can be calculated accurately using modern MC techniques. Simulations accounting for the aforementioned complexities indicate dose discrepancies exceeding a factor of ten to selected critical structures compared to conventional dose calculations. Task Group 129 was formed to review the literature; re-examine the current dosimetry calculation formalism; and make recommendations for eye-plaque dosimetry, including evaluation of brachytherapy source dosimetry parameters and heterogeneity correction factors. A literature review identified modern assessments of dose calculations for Collaborative Ocular Melanoma Study (COMS) design plaques, including MC analyses and an intercomparison of treatment planning systems (TPS) detailing differences between homogeneous and heterogeneous plaque calculations using the American Association of Physicists in Medicine (AAPM) TG-43U1 brachytherapy dosimetry formalism and MC techniques. This review identified that a commonly used prescription dose of 85 Gy at 5 mm depth in homogeneous medium delivers about 75 Gy and 69 Gy at the same 5 mm depth for specific (125)I and (103)Pd sources, respectively, when accounting for COMS plaque heterogeneities. Thus, the adoption of heterogeneous dose calculation methods in clinical practice would result in dose differences >10% and warrant a careful evaluation of the corresponding changes in prescription doses. Doses to normal ocular structures vary with choice of radionuclide, plaque location, and prescription depth, such that further dosimetric evaluations of the adoption of MC-based dosimetry methods are needed. The AAPM and American Brachytherapy Society (ABS) recommend that clinical medical physicists should make concurrent estimates of heterogeneity-corrected delivered dose using the information in this report's tables to prepare for brachytherapy TPS that can account for material heterogeneities and for a transition to heterogeneity-corrected prescriptive goals. It is recommended that brachytherapy TPS vendors include material heterogeneity corrections in their systems and take steps to integrate planned plaque localization and image guidance. In the interim, before the availability of commercial MC-based brachytherapy TPS, it is recommended that clinical medical physicists use the line-source approximation in homogeneous water medium and the 2D AAPM TG-43U1 dosimetry formalism and brachytherapy source dosimetry parameter datasets for treatment planning calculations. Furthermore, this report includes quality management program recommendations for eye-plaque brachytherapy.

Comparison of dose calculation methods for brachytherapy of intraocular tumors

PURPOSE

To investigate dosimetric differences among several clinical treatment planning systems (TPS) and Monte Carlo (MC) codes for brachytherapy of intraocular tumors using 125I or 103Pd plaques, and to evaluate the impact on the prescription dose of the adoption of MC codes and certain versions of a TPS (Plaque Simulator with optional modules).

METHODS

Three clinical brachytherapy TPS capable of intraocular brachytherapy treatment planning and two MC codes were compared. The TPS investigated were Pinnacle v8.0dp1, BrachyVision v8.1, and Plaque Simulator v5.3.9, all of which use the AAPM TG-43 formalism in water. The Plaque Simulator software can also handle some correction factors from MC simulations. The MC codes used are MCNP5 v1.40 and BrachyDose/EGSnrc. Using these TPS and MC codes, three types of calculations were performed: homogeneous medium with point sources (for the TPS only, using the 1D TG-43 dose calculation formalism); homogeneous medium with line sources (TPS with 2D TG-43 dose calculation formalism and MC codes); and plaque heterogeneity-corrected line sources (Plaque Simulator with modified 2D TG-43 dose calculation formalism and MC codes). Comparisons were made of doses calculated at points-of-interest on the plaque central-axis and at off-axis points of clinical interest within a standardized model of the right eye.

RESULTS

For the homogeneous water medium case, agreement was within approximately 2% for the point- and line-source models when comparing between TPS and between TPS and MC codes, respectively. For the heterogeneous medium case, dose differences (as calculated using the MC codes and Plaque Simulator) differ by up to 37% on the central-axis in comparison to the homogeneous water calculations. A prescription dose of 85 Gy at 5 mm depth based on calculations in a homogeneous medium delivers 76 Gy and 67 Gy for specific 125I and 103Pd sources, respectively, when accounting for COMS-plaque heterogeneities. For off-axis points-of-interest, dose differences approached factors of 7 and 12 at some positions for 125I and 103Pd, respectively. There was good agreement (approximately 3%) among MC codes and Plaque Simulator results when appropriate parameters calculated using MC codes were input into Plaque Simulator. Plaque Simulator and MC users are perhaps at risk of overdosing patients up to 20% if heterogeneity corrections are used and the prescribed dose is not modified appropriately.

CONCLUSIONS

Agreement within 2% was observed among conventional brachytherapy TPS and MC codes for intraocular brachytherapy dose calculations in a homogeneous water environment. In general, the magnitude of dose errors incurred by ignoring the effect of the plaque backing and Silastic insert (i.e., by using the TG-43 approach) increased with distance from the plaque's central-axis. Considering the presence of material heterogeneities in a typical eye plaque, the best method in this study for dose calculations is a verified MC simulation.