106Ruthenium eye plaque brachytherapy in the management of medium sized uveal melanoma

Comparing efficacy of charged-particle therapy with brachytherapy in treatment of uveal melanoma

BACKGROUND

Uveal melanoma (UM) is the most common primary ocular tumour in adults. The most used eye-preserving treatments are charged-particle therapy (CPT) and brachytherapy. We performed a systematic review and meta-analysis to compare efficacies and complications of these two radiotherapies.

METHODS

We searched EMBASE, PubMed, MEDLINE, and the Cochrane Library from January 2012 to December 2022. Two independent reviewers identified controlled studies comparing outcomes of CPT versus brachytherapy. Case series that utilize either treatment modality were also reviewed.

RESULTS

One hundred fifty studies met the eligibility criteria, including 2 randomized control trials, 5 controlled cohort studies, and 143 case series studies. We found significant reduction in local recurrence rate among patients treated with CPT compared to brachytherapy (Odds ratio[OR] 0.38, 95% Confidence interval [CI] 0.24-0.60, p < 0.01). Analysis also showed a trend of increased risks of secondary glaucoma after CPT. No statistically significant differences were found in analyzing risks of mortality, enucleation, and cataract.

CONCLUSIONS

Our study suggested no difference in mortality, enucleation rate and cataract formation rate comparing the two treatments. Lower local recurrence rate and possibly higher secondary glaucoma incidence was noted among patients treated with CPT. Nevertheless, the overall level of evidence is limited, and further high-quality studies are necessary to provide a more definitive conclusion.

Ruthenium-106 (106Ru) plaque brachytherapy for treatment of circumscribed choroidal hemangioma

PURPOSE

To describe the clinical and imaging features of circumscribed choroidal hemangiomas (CCH) and their treatment outcomes with Ruthenium-106 (106Ru) plaque brachytherapy.

METHODS

Retrospective study of 24 patients (24 eyes) diagnosed with CCH and treated with 106Ru plaque between 2017 and 2022. Analysis included pre- and post-treatment clinical and imaging features such as tumor regression, reduction in height, subretinal fluid (SRF) resolution, and change in best-corrected visual acuity (BCVA).

RESULTS

The mean age at presentation was 36 years (range, 16-57). The most common tumor location was the temporal quadrant (n = 19) with macular involvement (n = 13). Associated features were macular SRF (n = 22) and inferior exudative retinal detachment (n = 10). Nineteen of the 24 patients underwent primary treatment, whereas 5 patients underwent plaque as a salvage treatment. The mean tumor apex dose was 40 Gy. At a median follow-up of 7.5 months (range 3-65 months), 18 eyes showed complete regression, whereas 6 eyes showed partial regression. The mean height decreased from 4.8 (SD 1.28) mm at presentation to 2.5 (SD 1.63) mm. Median BCVA improved from logMAR 1.2 (IQR 0.4-2) at baseline to logMAR 1.05 (IQR 0.1-1.95) (p = 0.4). Complete resolution of the macula and tumor SRF was observed in 15 (68%) and 13 (57%) eyes, respectively. The radiation-related complications observed were radiation maculopathy (4 eyes), retinopathy (1 eye), and vitreous hemorrhage (1 eye).

CONCLUSION

Ruthenium-106 plaque brachytherapy is effective for CCH (> 3 mm height) as a primary and salvage treatment for tumors unresponsive to other modalities.

Apical dose versus volume dose of Ruthenium-106 brachytherapy for uveal melanoma

OBJECTIVE

Ruthenium-106 brachytherapy is commonly used to treat uveal melanomas. Most centres prescribe a radiation dose to the tumour apex that is calculated with the tumour located in the centre of the plaque. Recent work suggests that D99%-the minimum radiation dose delivered to 99% of tumour volume-may be a better predictor of tumour control than apex dose. Both dosing regimens may be affected by tumour and treatment variables differently. We explored the effect of differences in these variables on volume and apex dose using a 3-dimensional planning model.

METHODS

The time required to deliver 100 Gy to the tumour apices of representative tumours ranging from 2- to 6-mm thickness with central plaque positioning was calculated in Plaque Simulator™. This treatment time was used for further calculations, including D99% with central plaque placement, and apical and tumour volume doses when tumour and plaque characteristics were altered, including eccentric plaque placement, either away from (tilt) or along (offset) scleral surface, tumour shape, and plaque type.

RESULTS

D99% was always greater than the apex dose when plaques were placed centrally, and the difference increased with tumour thickness. Increasing degrees of tumour offset reduced apical dose and D99%, with a greater effect on apical dose for thicker and D99% for thinner tumours, respectively. Differences in tumour shape and plaque type had idiosyncratic effects on apical and volume dosing.

CONCLUSION

D99% and apex dose are affected by tumour and treatment characteristics in different ways, highlighting the complexity of radiation delivery to uveal tumours.

Combined photodynamic therapy and transpupillary thermotherapy for small choroidal melanoma

OBJECTIVE

The objective of this study was to determine whether combining verteporfin-based photodynamic therapy (PDT) and transpupillary thermotherapy (TTT) achieves adequate tumour control while maintaining visual acuity in individuals with small choroidal melanoma of amelanotic, melanotic, and variable pigmentation.

DESIGN

Individuals with posterior choroidal melanomas up to 3 mm in height underwent verteporfin-based PDT followed by immediate TTT. Further combined laser therapy was performed if a poor response was noted at 12 weeks or beyond. Tumours that demonstrated significant further growth were treated with brachytherapy or enucleation. A total of 37 eyes of 37 patients from the Terrace Eye Centre in Brisbane, Australia were studied. Average age of participants was 59.62 ± 12.45 years, and 17 of 37 participants were female (46%).

METHODS

This was a retrospective, noncomparative interventional study.

RESULTS

Seven of the 37 participants (19%) had recurrence of their tumour requiring further brachytherapy or enucleation. There was no statistically significant difference in visual acuity before and after treatment. There were no baseline characteristics that predicted treatment outcome. Ten individuals developed complications including epiretinal membrane (16%), scotoma (8%), cataract (3%), and macular edema (3%). No individuals experienced extraocular extension or progressed to metastatic disease. The mean follow-up time was 49 months.

CONCLUSION

Combined PDT and TTT achieved 81% tumour control in this study while preserving visual acuity. However, higher rates of local recurrence compared with brachytherapy warrant close follow-up to identify recurrences early.

Monte Carlo dosimetry of a novel Yttrium-90 disc source for episcleral brachytherapy

PURPOSE

To calculate the dose distribution using Monte Carlo simulations for a novel high-dose-rate Yttrium-90 (Y-90) disc source recently developed for episcleral brachytherapy and provide a lookup table for treatment planning.

METHODS

Monte Carlo simulations were performed to calculate the in-water dose distribution of the Y-90 disc source using the "GATE", a software based on the "Geant4" Monte Carlo simulation toolkit developed by the international OpenGATE collaboration. The geometry of this novel beta source, its capsule, and the surrounding water medium were accurately modeled in the simulation input files. The standard Y-90 element beta spectrum from ICRU 72 was used, and the physics processes for beta and photon interactions with matters were all included. The dose distribution of this Y-90 disc source was measured in a separate study using Gafchromic EBT-3 films and the results were reported elsewhere. To match the setup of the experiment, a Gafchromic EBT-3 film was also included in the simulation geometry. The simulated dose profiles were exported from the 3D dose distribution results and compared with the measured dose profiles. Transverse dose profiles at different distances from the seed surface were also obtained to study the lateral coverage of the source.

RESULTS

The measured percent depth dose (PDD) curves along the central axis perpendicular to the surface of the Y-90 disc were constructed from the experimental and simulated data, and normalized to the reference point at 1 mm from the source capsule. Both PDD curves agreed well up to 4 mm from the source surface (maximum difference ± 10%) but deviated from each other beyond 4 mm. The deviation might be caused by the increased measurement uncertainty in the low-dose region. The dose rate at the reference point calculated from the Monte Carlo simulation was 1.09 cGy/mCi-s and agreed very well with the measured dose rate of 1.05 cGy/mCi-s. If the 80% isodose line is selected as the lateral coverage, the lateral dose coverage is maximal (∼4.5 mm) at the plane next to the source surface, and gradually decreases with the increasing distance, approaching 3.5 mm when the plane is 5 mm from the 6-mm diameter source surface.

CONCLUSION

Monte Carlo simulations were successfully performed to confirm the measured PDD curve of the novel Y-90 disc source. This simulation work laid a solid foundation for characterizing the full dosimetry parameters of this source for episcleral brachytherapy applications.

Every other day stereotactic radiation therapy for the treatment of uveal melanoma decreases toxicity

BACKGROUND AND PURPOSE

To report the long-term results of stereotactic radiosurgery and fractionated stereotactic radiation therapy (SRS/FSRT) in patients with uveal melanoma (UM).

MATERIALS AND METHODS

We retrospectively evaluated the results of patients treated between 2007 and 2019. The primary endpoints were local control (LC), local recurrence-free survival (LRFS), enucleation-free survival (EFS) and treatment toxicity.

RESULTS

443 patients with 445 UMs were treated via CyberKnife®. According to the COMS classification, 70% of the tumors were small/medium and 30% were large. Median total RT dose was 54 Gy, median BED10 was 151 Gy. After a median 74-months follow-up, SRS/FSRT yielded an 83% overall LC rate. The 5- and 10-year LRFS rate was 74% and 56%, respectively. Patient age and the COMS size were prognostic for all survival endpoints. An increased SRS/FSRT dose was associated with higher LRFS and EFS rates. SRS/FSRT-related toxicity was observed in 49% of the eyes. Median visual acuity (VA) significantly deteriorated after SRS/FSRT in 76% of the treated eyes. The overall eye preservation rate was 62%, and the 5- and 10-year EFS rate was 64% and 36%, respectively. The delivery of FSRT every other day resulted in a significantly lower rate of toxicity and enucleation compared to FSRT on consecutive days.

CONCLUSION

A total dose of ≥45 Gy and BED_10Gy ≥ 112.5 SRS/FSRT is associated with a higher LC rate in patients with UM. Despite the favorable outcomes, treatment toxicity is the major limitation of this treatment. Toxicity and enucleation can be minimized by treating the eye every other day.

Ruthenium-106 plaque radiotherapy for uveal melanoma: analysis of tumor dimension and location on anatomical and functional results

Background

To report the long-term outcomes of Ru-106 plaque radiotherapy in eyes with uveal melanoma (UM) and to assess the effect of tumor thickness and location on final outcomes.

Methods

Medical records of 234 patients undergoing Ru-106 plaque radiotherapy for UM were reviewed, and the visual outcome, globe preservation, and patient survival were evaluated. The results of 2 groups were compared: 1. between thin (small and medium-sized, thickness < 7 mm, 148 eyes [63.2%]) and thick (thickness ≥ 7 mm, 86 eyes [36.8%]) tumors, and 2. between large (largest basal diameter [LBD] > 12 mm, 109 eyes [46.6%]) and medium/small (LBD ≤ 12 mm, 125 eyes [53.4%]). In addition, a comparison of the juxtapapillary location in 46 eyes (19.7%) versus tumors arising elsewhere and between tumors with and without ciliary involvement in 48 eyes (21.5%) were done.

Results

The patients were followed for a median of 54.2 months (range: 6–194.5 months). After adjusting for baseline visual acuity (VA), there was no significant association between final VA and different dimension and tumor location groups. Final globe preservation was 91.9%, and there was no significant difference between different dimension- and ciliary body involvement groups regarding anatomical success rate. The juxtapapillary tumors had lower globe preservation (80.4% vs .94.7%, p = 0.002). The hazard ratio (HR) for enucleation in juxtapapillary tumors was HR = 6.58 (95-CI: 3.84 to 11.21). The overall metastasis rate was 6.8%, with no significant difference in juxtapapillary tumors (4.3% vs.7.4%, p = 0.455).

Conclusions

Ru-106 plaque radiotherapy is an effective treatment for thick and large UM. With this type of treatment, the globe preservation rate is lower in juxtapapillary tumors, but there is no significant difference in the metastasis rate.

Treatment of Uveal Melanoma With Radioactive Iodine 125 Implant Compared With Proton Beam Radiotherapy

Objective

To review the current state of radiation therapy for uveal melanoma and compare particle radiation and brachytherapy.

Patients and Methods

The medical records of 156 patients treated for uveal melanoma between May 30, 2012, and March 16, 2020, were retrospectively reviewed. Treatments consisted of either radioactive iodine 125 implant (RAI) or fractionated proton radiation (proton beam therapy [PBT]). Baseline characteristics were compared using a Wilcoxon rank sum test or χ² test. Outcomes were compared using Cox proportional hazards regression models or logistic regression models.

Results

The median length of follow-up after treatment was 2.7 years (range, 0.5 to 9.0 years). Patients who underwent treatment with RAI were older (median age, 67 vs 59 years; P<.001) and had a lower tumor classification (American Joint Commission on Cancer; P=.001) compared with those who underwent PBT. There was no significant difference between RAI and PBT in the outcomes of liver metastases, death, enucleation, tearing, vision loss, retinal detachment, tumor thickness, conjunctivitis, optic neuropathy, iris neovascularization, or neovascular glaucoma (all P>.05). Patients who underwent RAI treatment had significantly higher risk of diplopia (P<.001), cataract progression (P<.001), and maculopathy (P=.03) compared with those who received PBT. Patients who underwent RAI were at higher risk of eyelash loss (P=.006) compared with the PBT group.

Conclusion

Treatment with PBT and RAI has similar efficacy; however, there are differences in the adverse outcomes associated with these 2 modalities.

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.

Outcomes for posterior uveal melanoma: Validation of American Brachytherapy Society Guidelines

PURPOSE

To assess outcomes of small and medium choroidal melanoma (less than 5.0 mm in height) following Iodine-125 episcleral brachytherapy.

METHODS AND MATERIALS

Patients with small and medium choroidal melanoma that underwent Iodine-125 brachytherapy with apical height of 1.0 mm to 5.0 mm and largest basal diameter of ≤16.0 mm were included. Data were extracted from the original dosimetry plans to determine doses to vision critical structures with the prescription point to the apical height (actual dose, ABS guidelines) and, after simulation, with the prescription point to the height of 5.0 mm (simulated dose, COMS protocol). Visual acuity (VA) outcomes with actual dose and that predicted with the simulated dose were estimated along with local recurrence, ocular survival, and survival at 5 years.

RESULTS

A total of 339 patients with a mean age of 61.5 years with a mean follow up duration of 43.4 months were included. The mean dose reduction for lens, optic disc, and fovea was 34%, 39.4%, and 41.4%, respectively with actual dose when compared with simulated dose. The Kaplan-Meier estimations for 3 year event free rate of VA of 20/50 or better were 56% and 31% for actual dose and simulated dose, respectively. Only 3 events of local recurrence were observed (enucleated) yielding 5 year local control and ocular survival rate of 98%. Overall survival (OS) and metastasis free survival (MFS) were 95% and 87.5% at 5 years, respectively.

CONCLUSIONS

Small and medium choroidal melanoma treated according to ABS has excellent outcomes. Brachytherapy planning using ABS guidelines as compared to COMS protocol may be associated with lower rates of radiation toxicity and vision loss.

Efficacy and complications of ruthenium-106 brachytherapy for uveal melanoma: a systematic review and meta-analysis

Purpose

The aim of this study was to evaluate the efficacy and vision-threatening complications of brachytherapy with ruthenium-106 (¹⁰⁶Ru) plaque to treat uveal melanoma.

Material and methods

A literature review was performed based on results from searching PubMed, Embase, Web of Science, Scopus, and Cochrane databases, using the following key words: “choroidal melanoma”, “uveal melanoma”, “brachytherapy”, and “ruthenium-106”. We included studies performed on more than 30 patients since 1986, reporting on local control rate, complications rate, mean radiation dose, and mean tumor thickness. The cumulative analysis was performed using Metaprop command of Stata v.16, and meta-regression was conducted based on mean tumor thickness and mean radiation dose to tumor’s apex.

Results

Twenty-one retrospective studies were selected, involving 3,913 patients treated primarily with ¹⁰⁶Ru plaque brachytherapy. The range of radiation dose to tumor apex was from 70 Gy to 250 Gy. The local control rate following brachytherapy ranged from 59% to 98%, and the overall weighted mean of local control was 84%. However, the heterogeneity between studies’ reports was remarkable (I² = 95.40%). Meta-regression based on tumor thickness and mean dose of radiation to the apex showed that the studies’ heterogeneity was minimally related to the difference in mean tumor size (I² = 92%). The correlation between larger tumor size and lower local control rate was statistically significant (p-value = 0.024). There was no significant correlation between the mean radiation dose and local control rate (p-value = 0.679). The most commonly reported complications were cataract and radiation-related retinopathy.

Conclusions

Although the studies’ heterogeneity was high, in a prescription dose ranging from 70 Gy to 250 Gy to the tumor apex, ¹⁰⁶Ru brachytherapy seems to be successful in local control of uveal melanoma. The efficacy of ¹⁰⁶Ru in controlling uveal melanomas decreased with the increase in tumor thickness. However, these outcomes should be verified in randomized comparative studies.