Development of a streamlined, non-invasive robotic radiosurgery method for treatment of 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.

Self-Shielding Gyroscopic Radiosurgery for Uveal Melanoma: A First Case Report

Stereotactic radiosurgery (SRS) is a well-established treatment modality for the management of uveal melanoma, achieving high tumor control and eye retention rates. There are several SRS treatment platforms available, including the recently developed self-shielding gyroscopic radiosurgery (GRS) system. We report the first use of GRS in the treatment of uveal melanoma. We report the treatment of a 63-year-old female patient with a left-sided uveal melanoma. Akinesia of the ocular globe in the orbit was achieved by retrobulbar anesthesia. The treatment plan used six isocenters (three with the 10 mm and three with the 7.5 mm apertures) and 140 beams to cover 99.2% of the planning target volume (PTV) with 21 Gy at the 54% isodose line. Treatment was delivered in a single session with the GRS device. The total workflow time from retrobulbar anesthesia to completion of treatment was 122 minutes. The procedure was flawless, clinically well tolerated by the patient, and reliably performed in an outpatient setting, thus comparable to our published experience with robotic SRS. The evaluation of new radiosurgery treatment platforms is critical to maintaining quality standards and refining future treatments.

Comparison of two optimization algorithms (VOLOTM , SEQU) for CyberKnife® treatment of acoustic neuromas, lung metastases, and liver metastases

INTRODUCTION

Two optimization algorithms VOLO™ and sequential optimization algorithm (SEQU) are compared in the Precision® treatment planning system from Accuray® for stereotactic radiosurgery and stereotactic body radiotherapy (SBRT) treatment plans. The aim is to compare the two algorithms to assess if VOLO™ is better of SEQU in certain treatment site.

MATERIALS AND METHODS

Sixty clinical treatment cases were compared. Entities include Acoustic neuroma (AN), lung metastases, and liver metastases. In each entity, 10 SEQU and 10 VOLO™ treatment plans were optimized. The Ray-Tracing calculation algorithm was used for all treatment plans and the treatments were planned exclusively with fixed cones (5-50 mm). The number of nodes, beams, total MU, and treatment time were compared. Conformity index (CI), new conformity index (nCI), homogeneity index (HI), gradient index (GI), and target coverage were examined for agreement. Dmin , Dmean , Dmax , D100%, D98%, and D2% dose in the target volume as well as exposure to organs at risk was checked. To determine peripheral doses, the isodose volumes from V10% to V98% were evaluated.

RESULTS

AN treatment plans showed significant differences for the number of nodes, beams, total MU, treatment time, D98%, D100% for the target volume, and the doses for all organs at risk. VOLO™ achieved better results on average. Total MU, treatment time, coverage, and D98% are significantly better for VOLO™ for lung metastases. For liver metastases, a significant reduction in number of nodes, total MU, and treatment time was observed for VOLO™ plans. The mean target coverage increased slightly with VOLO™, while the mean CI deteriorated slightly. The averages of Dmin , Dmean , D98%, D100%, and V80% resulted in a significant increase for VOLO™.

CONCLUSION

The results of the present study indicate that VOLO™ should be used in place of SEQU as a standard for AN cases moving forward. Despite the lack of significance in the lung and liver cases, VOLO™ optimization is recommended because OAR sparing was similar, but coverage, Dmin , and Dmean were increased, and thus better tumor control can be expected.

Stereotactic radiosurgery for medium and large uveal melanoma with a non-invasive eye immobilization device, a single institutional case series

PURPOSE

To investigate the treatment outcome, visual outcome, and adverse effects of five-fraction stereotactic radiosurgery (SRS) to medium- and large-sized uveal melanoma with a non-invasive eye immobilization device.

METHODS

Medical records of 14 patients with uveal melanoma receiving SRS with a total dose of 50 Gy in five fractions from 2008 to 2017 were retrospectively reviewed. A non-invasive eye fixation device was used to achieve and monitor eye immobilization.

RESULTS

Local tumor control rates were 85.7% and 75.0% at 2 and 5 years, respectively. The average tumor diameter decreased significantly from 10.0 ± 3.21 mm to 8.36 ± 3.71 mm (p = 0.038) 15 months after SRS, while the average tumor thickness decreased significantly from 5.45 ± 2.21 mm to 4.34 ± 2.29 (p = 0.036) 21 months after SRS. The 5-year metastasis-free survival was 87.5%. The mean best-corrected visual acuity (BCVA) deteriorated from logMAR 0.296 at baseline to logMAR 1.112 at the last individual follow-up visits (p < 0.001). Adverse effects of SRS were comparable to those reported with proton-beam radiotherapy or Gamma knife therapy.

CONCLUSION

SRS combined with a non-invasive eye immobilization device is an effective and safe alternative eye-preserving treatment for medium- to large-sized uveal melanoma. BCVA at 3 months may be a predictor for BCVA at 1 year.

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.

Robotic CyberKnife Radiosurgery for the Treatment of Choroidal and Ciliary Body Melanoma

PURPOSE

To present the results of robotic-assisted radiosurgery in choroidal and ciliary body melanomas treated at the Department of Ophthalmology of Ludwig-Maximilians-University and the European CyberKnife Center in Munich, Germany.

DESIGN

Interventional case series METHODS: This retrospective study included 594 consecutive patients referred to our clinic for the treatment of choroidal and ciliary body melanomas with robotic radiosurgery (CyberKnife) from 2005 to 2019. Eye retention, local control and disease-specific survival rates were calculated as Kaplan-Meier and actuarial estimates. The impact of prescription dose, tumor size, and ciliary body involvement was assessed by likelihood ratio tests and Cox regression.

RESULTS

Among all patients who were staged according to the TNM classification system (8th edition), 22.7% were I, 57.9% were II, 18.9% were III, and 0.5% were IV. Median apical tumor height and base diameter were 5.8 and 11.4 mm. The mean follow-up was 41.7 months. Local control after 3 and 5 years was 92.0% (95% CI = 88.2%-94.7%) and 84.3% (95% CI = 77.9%-89.0%), respectively, for 21 to 22 Gy and 86.9% (95% CI = 79.7%-91.7%) and 77.7% (95% CI = 68.5%-84.6%), respectively, when treated with 20 Gy or less. Eye retention was achieved in 89.9% and 81.0% after 3 and 5 years with 21 to 22 Gy and 85.9% and 80.0% for 20 Gy or less. Disease-specific survival rates were 93.1% (95% CI = 90.2%-95.2%) after 3 years, 89.8% (95% CI = 86.0%-92.6%) after 5 years, and 87.8% (95% CI = 82.8%-91.4%) after 7 years.

CONCLUSIONS

This is the largest series of patients treated for choroidal and ciliary body melanomas with CyberKnife. Our results reflect an improvement in the outcome of CyberKnife therapy for patients with choroidal and ciliary body melanoma treated with single-session radiosurgery in the last decade.

Outcomes of fractionated CyberKnife radiosurgery in patients with choroidal malignant melanoma

OBJECTIVE

The aim of this study was to evaluate local tumor control and complication development rates of fractionated CyberKnife radiosurgery (CRS) in patients with choroidal melanoma.

METHODS

A total of 29 patients with choroidal melanoma were treated with fractionated CRS at Ankara Oncology Research and Training Hospital, Department of Radiotherapy between May 2009 and December 2013. Patients were treated with CRS if the initial height of the choroidal melanoma was ≥ 6 mm, or juxtapapillary and/or juxtamacular tumors with a height of >2.5 mm. Ophthalmic examinations were performed at baseline and at months 3, 6, 9 and 15 after radiotherapy. Assessment of visual acuity and measurement of tumor base dimension and height using A-scan and B-scan echography were done at each visit.

RESULTS

The mean age was 56 (27-75) years. Tumor was located on choroid in 23 and on ciliochoroid in 6 patients. 86.2% of all melanomas were classified as medium sized and 23.8% as large sized. A median total dose of 5000 cGy was applied. Median tumor height decreased from 7.5 mm at baseline to 4.4 mm at the last follow-up visit (p < 0.001). Median visual acuity decreased from 0.4 at baseline to hand motion (p < 0.001). One patient had been lost to the metastatic disease and one patient had been treated with enucleation due to recurrent tumor growth.

CONCLUSION

CRS is an effective and reliable local treatment modality in uveal melanoma.

Feasibility, Method and Early Outcome of Image-Guided Volumetric Modulated Arc Radiosurgery Followed by Resection for AJCC Stage IIA–IIIB High-Risk Large Intraocular Melanoma

Simple Summary

The aim of this trial was to define one optimal contemporary treatment procedure for large intraocular melanoma. Radiosurgery is a highly effective treatment in cancer. In this trial, all consecutive patients with large intraocular melanoma treated with multimodality treatment, comprising 4D image-guided volumetric modulated arc radiosurgery procedure followed by resection, were evaluated. In the short-term follow-up there was no clinical toxicity due to external beam radiation therapy, and no local tumor recurrence. In 98% of the cases, the eye bulb could be maintained with partial residual visual acuity in the mean follow-up of 18 months. The outcome estimates one optimal treatment procedure for high-risk, large intraocular melanoma, with excellent results in the first follow-up.

Abstract

The main objective of this prospective observational study was the characterization of the feasibility and early outcome of image-guided (IG) volumetric modulated arc (VMAT) radiosurgery (SRS) followed by resection for patients with large intraocular melanoma. Our study included consecutive patients with unfavorable-risk melanoma, enrolled in an ophthalmic oncology center. IG-VMAT-SRS was applied by high-resolution 4D image guidance and monitoring. Current stereotactic technique parameters were evaluated for comparison. Side effects and eye function, based on a 5-point CTC assessment score, were quantified. In patients with tumors located more than 0.7–1 mm apart from the optic nerve, partial to complete volume-sparing of the optic nerve head could be achieved. In 95.5% of this subgroup, the vitality of the optic nerve and vision could be preserved by the multimodality-treatment approach (mean follow-up: 18 months (7.5–36 months)). The advanced technology of stereotactic radiotherapy demonstrated the achievability of steep dose gradients around the high-dose volume, with 4D-IG-VMAT dose application. These results enforce IG-VMAT-SRS followed by resection as one of the major therapeutic options for patients with large intraocular melanoma. The combination of 4D-IG high-precision SRS and resection provides an effective treatment for large intraocular melanoma, with few side effects, and enables an eye bulb and even vision preserving modus operandi.

Robotic CyberKnife radiosurgery for small choroidal melanomas

Plaque brachytherapy is the most common procedure for the treatment of small choroidal melanoma, especially in posteriorly located tumors. However, there is only little information on outcome after treatment with stereotactic radiosurgery, for example, CyberKnife radiosurgery. We reviewed patients with choroidal melanoma (maximum tumor height 4 mm) treated with CyberKnife radiosurgery. Demographic information, tumor dimension, complications, metastasis and overall survival during the whole follow-up were tracked and analyzed with a specific focus on local tumor control and potential risk factors. One hundred eighty-eight patients (102 female, 54.2%) with a median age of 63 years [interquartile range (IQR): 54-73 years] were analyzed over a median of 46 months (IQR: 24-62 months). Metastasis occurred in 14 patients (7.4%) in median of 18 months after treatment (IQR: 13-47 months) and survival was achieved in 178 patients (94.7%). Within the observation period, eye retention was observed in 166 patients (88.3%). Superior local control was achieved in patients who received a prescription dose of at least 21 Gy or more (91.6%; P = 0.04). Other potential risk factors incrementing local control were treatment planning with missing MRI in advance and too small target delineation during the planning process. Radiosurgery (CyberKnife) in a single, outpatient procedure is suitable for the treatment of small choroidal melanoma. We found local control rate after 3 years compared to the standard treatment with plaque brachytherapy. On the study side, 15 years of CyberKnife treatment allowed to identify risk factors that might increment local control and thus improve treatment regimens.

SLC25A38 as a novel biomarker for metastasis and clinical outcome in uveal melanoma

Risk of metastasis is increased by the presence of chromosome 3 monosomy in uveal melanoma (UM). This study aimed to identify more accurate biomarker for risk of metastasis in UM. A total of 80 patients with UM from TCGA were assigned to two groups based on the metastatic status, and bioinformatic analyses were performed to search for critical genes for risk of metastasis. SLC25A38, located on chromosome 3, was the dominant downregulated gene in metastatic UM patients. Low expression of SLC25A38 was an independent predictive and prognostic factor in UM. The predictive potential of SLC25A38 expression was superior to that of pervious reported biomarkers in both TCGA cohort and GSE22138 cohort. Subsequently, its role in promoting metastasis was explored in vitro and in vivo. Knock-out of SLC25A38 could enhance the migration ability of UM cells, and promote distant metastasis in mice models. Through the inhibition of CBP/HIF-mediated pathway followed by the suppression of pro-angiogenic factors, SLC25A38 was situated upstream of metastasis-related pathways, especially angiogenesis. Low expression of SLC25A38 promotes angiogenesis and metastasis, and identifies increased metastatic risk and worse survival in UM patients. This finding may further improve the accuracy of prognostic prediction for UM.

Clinical outcomes and secondary glaucoma after gamma-knife radiosurgery and Ruthenium-106 brachytherapy for uveal melanoma: a single institution experience

We retrospectively analyzed data from records of 48 patients (48 eyes) treated with gamma-knife (n = 18) or Ruthenium-106 brachytherapy (n = 30) for uveal melanoma, in our Ocular Oncology Unit between December 2013 and September 2019, with the aim to evaluate treatment outcomes, and incidence and risk factors for secondary glaucoma. Patients demographics and tumor characteristics at diagnosis were recorded. Follow-up data were collected regarding local tumor control, treatment complications, enucleation need, metastases occurrence and survival status. The median follow-up period was 33.7 months in the gamma-knife group and 26.2 months in the brachytherapy group. The mean tumor thickness, the largest basal diameter and the tumor volume were significantly higher in the gamma-knife group than in the brachytherapy group. The local tumor control rate was 100% in the brachytherapy group and 77.8% in the gamma-knife group. In the gamma-knife group, six patients were enucleated, no patient treated with brachytherapy underwent enucleation. The overall survival rate was 96.7% in the brachytherapy group and 94.44% in the gamma-knife group. Secondary glaucoma occurred in 10 patients after gamma-knife and in one patient after brachytherapy: it should be emphasized that larger lesions were treated with gamma-knife, whereas smaller tumors were selected for brachytherapy. We found a significative correlation of tumor thickness (P value = 0.043) and volume (P value = 0.040) with secondary glaucoma occurrence after gamma-knife treatment. Moreover, secondary glaucoma significantly correlated with radiation retinopathy in the gamma-knife group (P value = 0.009). This study shows preliminary clinical results that could be useful for further studies with more patients and longer follow-up.

Robotic-assisted radiosurgery for the treatment of vasoproliferative tumours

PURPOSE

Vasoproliferative tumours (VPT) are a rare but benign entity that can lead to severe visual acuity deterioration. There is no standard of care, and depending on the degree of clinical features, including tumour size and dissemination, visual acuity and subretinal fluid, treatment options include observation, cryotherapy and brachytherapy. Particularly in larger tumours, brachytherapy has advantages over other options, although higher radiation doses and the need for surgical application are disadvantages of this otherwise effective treatment option. CyberKnife radiosurgery might represent an alternative therapeutic option as no surgical intervention is needed and radiation doses are lower.

METHODS

All patients diagnosed with vasoproliferative tumors who were treated with CyberKnife radiosurgery with a minimum follow-up time of 12 months were included in this case series. We recorded visual acuity, number of lesions, central retinal thickness with optical coherence tomography (OCT) and reflectivity using A-scan standardizes echography every three months.

RESULTS

A total of four patients with a median age of 34 years (range: 24 - 51) who were observed over an average of 26.5 months (range: 17 - 49 months) matched our inclusion criteria. We appreciated stabilization or increase in visual acuity in all four patients and a regression in tumour thickness with subsequent increase in internal reflectivity as a marker of increasing fibrosis.

CONCLUSION

We observed good visual and functional outcome following CyberKnife therapy for VPT. We believe that further studies should be pursued to evaluate CyberKnife therapy for the treatment of VPT not treatable with cryo- or lasertherapy.

Evaluation of Choroidal Melanoma Vascularization by Color Doppler Flow Imaging: An Option for Follow-Up Tumor Control Assessment after CyberKnife®?

Background and Objectives: Thus far, tumor control for choroidal melanoma after teletherapeutic radiation is clinically difficult. In contrast to brachytherapy, the tumor height does not necessarily have to shrink as a result of teletherapy. Therefore, the objective of this study was to evaluate tumor vascularization determined by color Doppler flow imaging (CDFI) as a possible approach for monitoring the therapy response after teletherapy of choroidal melanoma. Materials and Methods: A single-center retrospective pilot study of 24 patients was conducted, all of whom had been diagnosed with choroidal neoplasm, treated and followed up. Besides tumor vascularization, the following parameters were collected: age, gender, tumor entity, location, radiation dose, knowledge of relapse, tumor height, radiation-related complications, occurrence of metastases, visual acuity in logMAR. Results: The level of choroidal melanoma vascularization markedly decreased in all included subjects after treatment with the CyberKnife^® technology. Initially, the level of vascularization was 2.1 (SD: 0.76 for n = 10); post-therapeutically, it averaged 0.14 (SD: 0.4). Regarding the tumor apex, CDFI sonography also demonstrated a significant tumor regression (mean value pre-therapeutically: 8.35 mm—SD: 3.92 for n = 10; mean value post-therapeutically: 4.86 mm—SD: 3.21). The level of choroidal melanoma vascularization declined in the patient collective treated with ruthenium-106 brachytherapy. The pre-therapeutic level of vascularization of 2 (SD: 0 for n = 2) decreased significantly to a level of 0 (mean: 0—SD: 0). The tumor height determined by CDFI did not allow any valid statement regarding local tumor control. In contrast to these findings, the patient population of the control group without any radiation therapy did not show any alterations in vascularization. Conclusions: Our data suggest that the determination of the tumor vascularization level using CDFI might be a useful and supplementary course parameter in the follow-up care of choroidal melanoma to monitor the success of treatment. This especially applies to robot-assisted radiotherapy using CyberKnife^®. Further studies are necessary to validate the first results of this assessment.

Dosimetric comparison and secondary malignancy risk estimation for linac-based and robotic stereotactic radiotherapy in uveal melanoma

It was aimed to investigate the dosimetric differences among linac-based and robotic stereotactic radiotherapy (SRT) techniques for the treatment of uveal melanoma and to evaluate secondary malignancy risks for these different SRT techniques. Ten patients who received robotic SRT with CyberKnife were retrospectively included in this study. A total dose of 54 Gy in three fractions was prescribed to the planning target volume (PTV). For each patient, non-coplanar micro-multileaf collimator based dynamic conformal arc (DCA), intensity-modulated radiotherapy (IMRT) and circular cone based DCA (cDCA) plans were generated. During the analysis dose-volume histogram (DVH) parameters, homogeneity index, new conformity index, the volume received more than or equal to 30% and 50% of the prescribed dose were compared. Additionally, secondary malignancy risk for each technique was estimated using the risk factors recommended by The International Commission on Radiological Protection. Robotic SRT plans provided a high degree of conformity within the PTV and better normal tissue sparing compared to linac-based treatment plans. However, dose distribution was more heterogeneous in robotic SRT plans than that in linac-based techniques. Estimated secondary malignancy risk was also found as 3.4%, 1.4%, 1.4% and 1.6% for robotic SRT and linac-based IMRT, DCA, cDCA plans, respectively. Treatment parameters of uveal melanoma patients planned with robotic SRT had superior conformity and organ-at-risk (OAR) sparing compared with those planned with the linac-based system. However, estimated secondary malignancy risk was almost two-times higher in robotic SRT than that in linac-based techniques.

Iatrogenic Ocular Surface Diseases Occurring during and/or after Different Treatments for Ocular Tumours

Simple Summary

The ocular surface represents a finely regulated system that allows the protection of the eye. It can be affected by therapies used for the treatment of various intraocular tumours, particularly conjunctival cancers and uveal melanoma. In these conditions, treatments are chosen according to the characteristics of the lesion, and include a combination of selective surgery, anticancer eye drops, and/or radiotherapy delivered through different mechanisms. Possible side effects affecting the ocular surface range from transient dry eye or keratitis up to more severe complications such as corneal melting and perforation. These complications deserve careful evaluation for the risk of permanent sight-threatening sequelae. Physicians involved in the management of patients affected by ocular tumours should be aware of this risk in order to reach an early diagnosis and promptly set up an adequate treatment. The present review summarizes acute and chronic complications affecting the ocular surface following different therapies for the treatment of conjunctival cancers and uveal melanoma, and also reports clinical cases of representative patients who experienced these complications.

Abstract

The ocular surface represents a finely regulated system that allows the protection of the eye. It is particularly susceptible to different treatments for intraocular tumours, such as uveal melanoma and conjunctival cancers. Traditionally, the management of ocular tumours depends on the characteristics of the lesion, and is based on a combination of selective surgery, topical chemotherapy, and/or radiotherapy delivered through different mechanisms (e.g., charged-particle radiotherapy or brachytherapy). Possible complications involving the ocular surface range from transient dry eye disease or keratitis up to corneal melting and perforation, which in any case deserve careful evaluation for the risk of permanent sigh-threatening complications. Clinicians involved in the management of these patients must be aware of this risk, in order to reach an early diagnosis and promptly set up an adequate treatment. The present review of the literature will summarize acute and chronic complications affecting the ocular surface following different therapies for the treatment of ocular tumours.

Robotic assisted CyberKnife radiosurgery for the treatment of iris melanoma

Iris melanoma is a rare form of uveal melanoma with potential metastic spread. Treatment options include surgical resection, enucleation or irradiation. We analysed visual outcome, complication appearance and management in eight patients with iris melanoma following robotic-assisted CyberKnife treatment. Consecutive patients from the Department of Ophthalmology at University of Munich were included in the study if they had an iris melanoma that was treated with CyberKnife and had a minimum follow-up of 12 months. We evaluated tumor thickness, largest diameter, visual acuity and complications. 8 patients were included in this report. The median age was 74 years (range: 53-86 years). The median follow-up was 23 months (range 12-48 months). Tumor thickness decreased from 2.1 to 1.4 mm on average. Four out of eight patients showed stable or increased visual acuity compared to visual acuity at first visit. We did not find a correlation of applied radiation volume or radiation dose on visual outcome. Radiation keratopathy was the most common complication in five patients. No recurrences were noted. Robotic-assisted radiosurgery following CyberKnife is a promising non-invasive, single session treatment option for iris melanoma with comparable results regarding recurrence rate or complications to brachytherapy and proton beam therapy. All included patients showed good visual outcome.

Robotic assisted CyberKnife radiosurgery for the treatment of choroidal metastasis

PURPOSE

Choroidal metastases occur in many patients with systemic cancer and limit quality of life due to visual deterioration or pain. The limited prognosis of these patients demand treatment approaches that aim at a quick response and easy application. We evaluated a robotic assisted radiosurgery device, the CyberKnife, in the treatment of choroidal metastasis.

METHODS

Following retrobulbar anaesthesia, target volume was defined by an interdisciplinary team using gadolinium-contrast-enhanced MRI, computer tomography (CT) as well as all previously obtained clinical data. Radiation was delivered in a single fraction with a CyberKnife at a radiation dose of 21 Gy with a 70% isodose. We evaluated tumour height, reflectivity, visual acuity and side effects over the course of the follow-up.

RESULTS

A total of four patients were included in this report. Mean follow-up time was 31 months, and all patients showed decreased tumour volume and signs of fibrosis during follow-up. One patient remained stable in terms of visual acuity, two patients lost visual acuity and one patient improved and had a functional visual acuity at last follow-up. One patient developed radiation retinopathy with subsequent neovascular glaucoma that needed further management. All other patients did not show any signs of radiation induced side effects.

CONCLUSION

We report on the outcome of robotic CyberKnife radiosurgery in the treatment of uveal metastasis. We believe that single session, outpatient treatment delivery that can be facilitated with CyberKnife radiosurgery offer some benefits for this particularly sick group of patients.

Early Results of Stereotactic Radiosurgery in Uveal Melanoma and Risk Factors for Radiation Retinopathy

Objectives:

To report treatment results and complications of stereotactic radiosurgery in uveal malignant melanoma and to identify risk factors for development of radiation retinopathy.

Materials and Methods:

This was a retrospective study of 36 patients diagnosed with uveal melanoma between 2014 and 2019. Best corrected visual acuity, funduscopic findings, basal tumor diameter and tumor thickness were recorded at baseline and at follow-up visits at 3-month intervals. The response of tumors to stereotactic radiosurgery and complications were determined.

Results:

The mean basal diameter of tumor was 10.2 (range: 4.0-19.4, standard deviation [SD]: ±3.3) mm x 9.7 (range: 4.5-18.0, SD: ±3.3), tumor thickness was 5.1 (range: 2.0-11.0, ±2.4) mm at baseline. The mean follow-up period was 17.2 (range: 6-48, SD: ±10.43) months. The mean visual acuity was 0.5 (SD: ±0.3) logMAR before treatment and 0.6 (SD: ±0.3) logMAR after the mean follow-up period. The most common complications after stereotactic radiosurgery were cataract (38.9%) and radiation retinopathy (27.7%). There was a statistically significant relation between radiation retinopathy development and tumor distance from the optic disc (p=0.04). The rate of eye salvage was 83.3% in this study.

Conclusion:

Our short-term results show stereotactic radiosurgery was an effective and sustained treatment modality among the other eye conservation therapies.

Frameless radiosurgery for intraocular metastatic tumor: Case report

AIM

The aim of this case report is to describe the technique and response using frameless radiosurgery technique in intraocular metastases.

BACKGROUND

Intraocular metastases are the most common malignant lesion within the eye and its prevalence is probably underestimated. This is of great interest for oncologist as there are new treatment options with high rates of tumor control maintaining patient's quality of life.

CASE REPORT

We report a case of a 54-year-old female with intraocular metastases from breast cancer using a frameless radiosurgery technique allowing organ preservation.

CONCLUSION

The frameless robotic radiosurgery system is feasible and comfortable option for patients with intraocular metastases. Treatment planning and delivery requires an experienced interdisciplinary team.

[Technical aspects and indications of extracranial stereotactic radiotherapy]

Extracranial stereotactic radiotherapy has developed considerably in recent years and is now an important part of the therapeutic alternatives to be offered to patients with cancer. It offers opportunities that have progressively led physicians to reconsider the therapeutic strategy, for example in the case of local recurrence in irradiated territory or oligometastatic disease. The literature on the subject is rich but, yet, there is no real consensus on therapeutic indications. This is largely due to the lack of prospective, randomized studies that have evaluated this technique with sufficient recoil. We propose a review of the literature on the technical aspects and indications of extracranial stereotactic radiotherapy.

Feasibility of Image-Guided Robotic Radiotherapy using Three Fractions for Uveal Melanoma

Aims

A retrospective study was performed to demonstrate the feasibility and efficacy of 3-fraction image-guided robotic stereotactic radiotherapy (fSRT) for uveal melanoma.

Materials and Methods

Six patients with medium-sized or large tumors, who declined enucleation, were enrolled. The gross tumor volume (GTV) ranged from 454 to 2185 mm3. The total doses included 36 or 39 Gy in 3 fractions.

Results

Follow-up ranged from 19 to 40 months. In 5 patients, the tumor mass gradually underwent an average 24.5% size reduction. All 3 patients with a GTV <1000 mm3 had a functional eye, while 3 patients with a GTV ≥1000 mm3 did not have a functional eye. Radiation-induced complications occurred to some degree in all patients. However, complications that required enucleation were not detected.

Conclusion

We suggest that image-guided robotic radiotherapy using 3 fractions is a feasible and safe treatment option for patients with uveal melanoma. In cases of medium-sized and large tumors, fSRT could be used as an alternative treatment for cases ineligible for brachytherapy, but a longer follow-up and a larger number of patients are required to confirm the suitability of the method.

Incidence of secondary glaucoma after treatment of uveal melanoma with robotic radiosurgery versus brachytherapy

PURPOSE

Different modalities of radiation therapy nowadays allow for effective treatment of uveal melanoma combined with the advantage of eye preservation. However, this advantage can secondarily be impaired by radiation-related side effects. After local recurrence, secondary glaucoma (SG) has been described as second most frequent complication leading to need of enucleation. This study compares the incidence of SG after conventional Ruthenium (Ru)-106 brachytherapy (BT) versus CyberKnife robotic radiosurgery (RRS) which has been gaining importance lately as an efficient treatment option offering improved patient comfort.

METHODS

Medical records of all patients diagnosed with uveal melanoma in the Eye Clinic of the Ludwig-Maximilians-University Munich between 2007 and 2013 were reviewed. A total of 268 eyes of 268 patients treated with Ru-106 BT or CyberKnife-RRS as monotherapy were entered in this retrospective cohort study. Incidence of SG was correlated with treatment modality and baseline tumour characteristics.

RESULTS

Fifty-three patients (19.8%) developed SG. At 5 years, SG was significantly more frequent after RRS (46.7%) than BT (11.1%); however, tumour thickness (maximum apical height) as a marker of tumour progress was more pronounced in the RRS group. Subgroup analysis of 178 patients for tumours amenable to both BT and RRS (thickness ≤6 mm) revealed comparable results at 3 years (RRS: 13.8 versus BT: 11.2%), but a trend towards increased incidence after RRS beyond year three. However, this difference was not significant at 5 years (28.2% versus 11.2%, p = 0.138). Tumour thickness was significantly associated with incidence of SG.

CONCLUSION

In tumours ≤6 mm thickness, RRS and BT seem to offer a comparable safety profile in terms of SG. Beyond year three, SG was tendentially, but not significantly more frequent after RRS. Increasing tumour thickness is associated with risk of SG.

[CyberKnife®: new treatment option for uveal melanoma]

BACKGROUND

CyberKnife® stereotactic radiosurgery is a new treatment option for uveal melanoma.

OBJECTIVE

This review outlines the technique of robot-assisted CyberKnife® therapy, as well as the pros and cons in the treatment of uveal melanoma.

METHODS

The study provides a PubMed literature review and own preliminary clinical experiences.

RESULTS

CyberKnife® therapy for choroidal and ciliary body melanomas shows comparable results concerning local tumor control and overall survival matching those of conventional therapies. With only low complication rates, a high level of quality of life can be conserved by possible preservation of visual acuity as well as the ocular globe.

CONCLUSION

Stereotactic radiosurgery using CyberKnife® seems to be an efficient and safe therapeutic option for malignant melanomas affecting the choroid and ciliary body. Comparative studies with conventional radiation strategies are now a high priority.

Staged Radiosurgical Ablation for Choroid Melanoma: A Case Report with Emphasis on the Role of Patient Preparation, Treatment Planning, and Precision of Delivery

The aim of reporting this case of choroid melanoma of the left eye is to introduce the in-house-designed treatment planning protocol for fractionated radiosurgical ablation of an intraocular lesion. This is a clinical case with emphasis on treatment preparation and delivery using the Accuray CyberKnife Robotic Radiosurgery System (Accuray, Sunnyvale, CA, USA) for a patient immobilized with a head mask and our in-house-made eye fixation system.

Quality of life in the follow-up of uveal melanoma patients after enucleation in comparison to CyberKnife treatment

PURPOSE

To compare quality of life (QoL) in patients with uveal melanoma after enucleation and stereotactic radiosurgery to that in an age-matched patient collective.

METHODS

QoL was assessed in a cross-sectional survey and compared among 32 uveal melanoma patients after enucleation, 48 patients after stereotactic radiosurgery (CyberKnife(®); Accuray(®) Incorporated, Sunnyvale, CA, USA), and an age-matched control group of 35 patients, using the SF-12 Health Survey. Statistical analysis was performed with Fisher's exact test, Student's t test, one-way ANOVA analysis, Wilcoxon rank-sum (Mann-Whitney test), and ordered logistic regression for multivariate analysis.

RESULTS

There was no significant difference in QoL between patients treated by stereotactic radiosurgery and the age-matched control group. After enucleation, patients presented significantly lower values in Physical Functioning (PF), Role Physical (RP), and Role Emotional (RE) compared to the radiosurgery and control group. To control for the overall QoL lowering effect of visual loss, the QoL of the patients who underwent enucleation was compared with the QoL of patients suffering severe functional loss after CyberKnife radiosurgery in a subgroup analysis, which showed no statistically significant difference. The number of comorbidities had a significant impact on QoL in multivariate analysis.

CONCLUSIONS

Superior performance in PF, RP, and RE suggests that CyberKnife represents a suitable first-line therapy for uveal melanoma. In cases with painful amaurosis or vast tumor recurrence, enucleation can be performed with an acceptable QoL outcome.

[Solitary spinal metastases. Is aggressive surgical management justified?]

Advances in oncological and surgical therapies have led to a significant increase in life expectancy of cancer patients and also prolonged survival of patients with isolated or multiple metastases. Among the skeletal manifestations the spine is the most often affected site. Using novel imaging techniques with higher resolution and use of metabolic signatures, the screening of cancer patients has improved considerably. Consequently, the diagnosis of metastases is becoming increasingly more sensitive. Therefore, but also due to more effective polychemotherapy protocols, singular or solitary metastases are more frequently observed either in the early stages or as a result of a controlled malignant tumor entity (stable disease). The questions whether a solitary metastasis really exists (illusion or reality?) and its radical oncological and surgical treatment as a circumscribed singular tumor manifestation, is really relevant for the overall prognosis, remains controversial. However, it seems evident that a biologically favorable underlying tumor biology, radical treatment of the primary tumor and a long metastasis-free interval are valid predictors of a good oncological outcome. In the presence of a solitary metastasis under these circumstances (typical example: solitary metastasis of renal cell carcinoma many years after radical tumor nephrectomy) a radical surgical procedure (en bloc spondylectomy) can significantly improve the long-term prognosis of this patient group in combination with adjuvant chemotherapy and/or radiotherapy. However, a thorough evaluation of the overall survival prognosis, a detailed and complete staging followed by a treatment consensus in the interdisciplinary tumor board has to precede any therapeutical decisions.

CyberKnife radiosurgery for the treatment of orbital metastases

Purpose of this study is to evaluate radiographic therapy response, clinical outcome and adverse effects of CyberKnife radiosurgery in patients suffering from orbital metastases. Sixteen orbital metastases originating from different solid cancers in fourteen patients were treated by single fraction CyberKnife radiosurgery. Radiographic response and clinical outcome were evaluated. The treated tumor volume ranged from 0.2 to 35 cm3 (median 2.3 cm3, mean 7.0 cm3, SD 6 10.4 cm3, CI 0.9-9.4 cm3). The prescription dose ranged from 16.5-21 Gy (median 18 Gy, mean 18.2 Gy, SD 6 1.2 Gy, CI 17.0-18.4 Gy). A no change situation was observed in nine lesions, partial remission in four as well as complete remission in one metastasis. Tumor growth was stabilized or regressive following CyberKnife therapy in 87% of the cases. Recurrence was observed in two cases (13%). Before therapy, three patients suffered from visual disturbance and five patients reported diplopia. Six patients had no initial symptoms. After therapy, one patient indicated improvement of the present visual deficit and two patients no change. Out of the two patients with persistent diplopia, two reported improvement after therapy and three no change. No progression of symptoms was noted in any of the cases. Fourteen out of sixteen treated lesions were stable or regressive following CyberKnife radiosurgery (87%). As no serious adverse effects were reported in this series, CyberKnife therapy was shown to be of great value for local management of orbital metastases.

Dose tolerance limits and dose volume histogram evaluation for stereotactic body radiotherapy

Almost 20 years ago, Emami et al. presented a comprehensive set of dose tolerance limits for normal tissue organs to therapeutic radiation, which has proven essential to the field of radiation oncology. The paradigm of stereotactic body radiotherapy (SBRT) has dramatically different dosing schemes but, to date, there has still been no comprehensive set of SBRT normal organ dose tolerance limits. As an initial step toward that goal, we performed an extensive review of the literature to compare dose limits utilized and reported in existing publications. The impact on dose tolerance limits of some key aspects of the methods and materials of the various authors is discussed. We have organized a table of 500 dose tolerance limits of normal structures for SBRT. We still observed several dose limits that are unknown or not validated. Data for SBRT dose tolerance limits are still preliminary and further clinical trials and validation are required. This manuscript presents an extensive collection of normal organ dose tolerance limits to facilitate both clinical application and further research.