Use Of Stereotactic Radiosurgery Research Articles

Stereotactic radiosurgery for vestibular schwannomas: evolution of the philosophy of treatment

Vestibular schwannomas are the most common tumors in the cerebellopontine angle. Stereotactic radiosurgery is included in the armamentarium of methods for treating these tumors along with surgical treatment. Given the annual incidence of more than 15 radiosurgical cases of vestibular schwannomas per 1 million population, the expected need for stereotactic radiosurgery of these tumors in Russia is more than 2000 cases annually.Stereotactic radiosurgery is located at the intersection of several clinical specialties: neuroradiology, neurosurgery and radiation therapy, each of which has made a significant contribution to the development of this treatment method. The most commonly used for this is the cobalt‑based Leksell Gamma Knife, specifically intended for the treatment of intracranial neoplasms. Treatment is also possible with modern linear accelerators and proton accelerators, which provide high accuracy and conformity of irradiation. The experience gained since the first application of this method in the treatment of vestibular schwannomas has made it possible not only to optimize the radiation doses to the tumor and adjacent critical structures (brain stem, inner ear), but also to study the features of post‑radiation micro‑ and macro‑ changes, their impact on the clinical course, to develop recommendations for radiosurgery with schwannomas of various sizes. All this contributes to high control of tumor growth and a low level of functional disorders, which, along with easy tolerability and minimal hospitalization time, determines lower cost of this treatment compared to the traditional surgical approach and significant social and economic effect.This lecture is intended for neurosurgeons and radiation therapists and focuses on the most significant factors that influenced the development, promotion and active use of stereotactic radiosurgery of vestibular schwannomas in cli nical practice.

Upfront stereotactic radiosurgery versus adjuvant radiosurgery for parasagittal and parafalcine meningiomas: a systematic review and meta-analysis.

Parafalcine and parasagittal (PFPS) are common locations for meningiomas. Surgical resection for these tumors, the first-line treatment, poses challenges due to their proximity to critical structures. This systematic review investigates the use of stereotactic radiosurgery (SRS) as a treatment for PFPS meningiomas, aiming to elucidate its safety and efficacy. The review adhered to PRISMA guidelines. Searches were conducted on MEDLINE, Embase, and Cochrane. Inclusion criteria involved studies on SRS for PFPS meningiomas, reporting procedure outcomes and complications. Tumors were presumed or confirmed to be WHO grade 1. Data was systematically extracted. Meta-analysis was performed where applicable. The review included data from eight studies, 821 patients with 878 lesions. Tumor control was achieved in greater than 80% of cases. Adverse radiation effects were reported in 7.3% of them. Recurrence and further surgical approach were observed in 17.1% and 9.2% of cases, respectively. Symptom improvement was noted in 33.2% of patients. Edema occurred in approximately 25.1% of patients. A subgroup of 283 patients had upfront SRS, achieving tumor control in approximately 97% of such cases. SRS is a safe and effective treatment for PFPS meningiomas, both as an adjuvant therapy and as an upfront treatment for often smaller tumors. Post-SRS edema can typically be managed medically and usually does not require further surgical intervention. Further studies should provide more specific data on PFPS meningiomas. The use of single and hypofractionated SRS for larger volume PFPS meningiomas should be more explored to better define the risks and benefits.

Overall survival following stereotactic radiosurgery for ten or more brain metastases: a systematic review and meta-analysis

BackgroundBrain metastases are the most common intracranial tumours. Variation exists in the use of stereotactic radiosurgery for patients with 10 or more brain metastases. Concerns include an increasing number of brain metastases being associated with poor survival, the lack of prospective, randomised data and an increased risk of toxicity.MethodsWe performed a systematic review and meta-analysis to assess overall survival of patients with ten or more brain metastases treated with stereotactic radiosurgery as primary therapy. The search strings were applied to MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). Log hazard ratios and standard errors were estimated from each included study. A random-effects meta-analysis using the DerSimonian and Laird method was applied using the derived log hazard ratios and standard errors on studies which included a control group.Results15 studies were included for systematic review. 12 studies were used for pooled analysis for overall survival at set time points, with a predicted 12 month survival of 20–40%. The random-effects meta-analysis in five studies of overall survival comparing ten or greater metastases against control showed statistically worse overall survival in the 10 + metastases group (1.10, 95% confidence interval 1.03–1.18, p-value = < 0.01, I2 = 6%). A funnel plot showed no evidence of bias. There was insufficient information for a meta-analysis of toxicity.DiscussionOverall survival outcomes of patients with ten or more brain metastases treated with SRS is acceptable and should not be a deterrent for its use. There is a lack of prospective data and insufficient real-world data to draw conclusions on toxicity.PROSPERO IDCRD42021246115

Stereotactic radiosurgery for patients with brain metastases from gastroesophageal cancers.

The prognosis of patients with brain metastases from gastroesophageal (GE) cancers remains unclear despite recent advances in systemic therapies. The authors present a large single-institution experience in the use of stereotactic radiosurgery (SRS). A retrospective review of 71 GE cancer patients (64 male, 90.14%) who underwent Gamma Knife SRS was conducted. Overall, 243 brain metastases were treated and the median number of metastases per patient was 2 (range:1-21). The median age at SRS was 66 years (range: 26-85) and the median treatment day KPS was 80 (range: 50-100). The median cumulative tumor volume was 6.7cc (range: 0.27-104.76) and the median single-session margin dose was 18Gy (range: 12-20). The median overall survival after SRS was 7 months (range: 1-64). At last follow up, 54 (76.06%) patients were deceased, 8 of whom (14.81%) expired secondary to their intracranial metastases. Four patients (5.63%) experienced local tumor progression at a median time of 8 months (range: 2-13) after SRS. Ten patients (14%) experienced new remote tumor development at a median time of 4 months (range: 0-14) after SRS. Whole-brain radiation therapy (2 patients, 20%) and repeat SRS (8 patients, 80%) were used for newly developed tumors. The incidence of transient adverse radiation effects was 8.45%. In this study, the 12-month local tumor control rate was 90%. Incidences of adverse radiation effect rates were rare. The median overall survival of 7 months indicates the poor prognosis of patients with brain spread of their GE cancer.

The Use of Stereotactic Radiosurgery to Treat Functional Disorders: A Topic Discussion

Stereotactic radiosurgery (SRS) is a well-known modality for the treatment of malignant brain tumors. SRS, however, can also be used to treat non-malignant functional disorders such as epilepsy, tremor, trigeminal neuralgia (TN), obsessive compulsive disorder (OCD), and intractable pain among others. Given the limited prospective data guiding treatment of these benign disorders, this article serves as a consolidated discussion of the application of SRS for functional ailments, hopefully serving as a reference for those considering application of this technique in clinical practice.

Use of stereotactic radiosurgery in treatment of brain metastases from pediatric extracranial solid tumors

Pediatric Blood & CancerEarly View e30303 LETTER TO THE EDITOR Use of stereotactic radiosurgery in treatment of brain metastases from pediatric extracranial solid tumors Suzanne Xu, Suzanne Xu Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorAllison Campbell, Allison Campbell Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorVeronica Chiang, Veronica Chiang Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorRanjit Bindra, Ranjit Bindra Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorJuan Vasquez, Juan Vasquez orcid.org/0000-0002-9031-7639 Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorFarzana Pashankar, Corresponding Author Farzana Pashankar [email protected] orcid.org/0000-0003-2883-0957 Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA Correspondence Farzana Pashankar, Department of Pediatrics, Yale University School of Medicine, LMP 2073, 333 Cedar St, New Haven, CT 06520, USA. Email: [email protected]Search for more papers by this author Suzanne Xu, Suzanne Xu Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorAllison Campbell, Allison Campbell Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorVeronica Chiang, Veronica Chiang Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorRanjit Bindra, Ranjit Bindra Department of Radiation Oncology, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorJuan Vasquez, Juan Vasquez orcid.org/0000-0002-9031-7639 Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USASearch for more papers by this authorFarzana Pashankar, Corresponding Author Farzana Pashankar [email protected] orcid.org/0000-0003-2883-0957 Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA Correspondence Farzana Pashankar, Department of Pediatrics, Yale University School of Medicine, LMP 2073, 333 Cedar St, New Haven, CT 06520, USA. Email: [email protected]Search for more papers by this author First published: 28 March 2023 https://doi.org/10.1002/pbc.30303 Suzanne Xu and Allison Campbell are the co-first authors. Manuscipt was presented as a short oral presentation at the International Society of Pediatric Oncology Annual conference (virtual) in 2020. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Early ViewOnline Version of Record before inclusion in an issuee30303 RelatedInformation

Role of Stereotactic Radiosurgery in the Management of Dural AV Fistula.

Dural arteriovenous fistulas (DAVFs) are a relatively rare intracranial vascular malformation. The various treatment options for DAVFs include observation, compression therapy, endovascular therapy, radiosurgery, or surgery. A combination of these therapies may also be used. The treatment choice for DAVFs depends on the type of fistula, the severity of symptoms, DAVF angioarchitecture, and the efficacy and safety of treatments. The use of stereotactic radiosurgery (SRS) in DAVFs started in the late 1970s. There is a delay before the fistula gets obliterated after SRS and there is a risk of hemorrhage from the fistula till the fistula gets obliterated. Initial reports described the role of SRS in small DAVFs without severe symptoms, which were inaccessible by endovascular or surgical measures or in combination with embolization in larger DAVFs. SRS can be appropriate for indirect cavernous sinus DAVF fistulas (Barrow type B, C, and D). Borden types II and III and Cognard types IIb-V DAVFs have a high risk of hemorrhage and are traditionally considered less favorable to be treated with SRS as immediate treatment is required to decrease the risk of hemorrhage. However, recently SRS has been tried in these high-grade DAVF as a monotherapy. Factors that have a positive impact on the obliteration rates of DAVF following SRS are the location of DAVF with the cavernous sinus DAVF having much better obliteration rates than DAVF located at other locations, Borden Type I or Cognard Types III or IV DAVFs, absence of CVD, hemorrhage at the time of initial presentation, and target volume lesser than 1.5 mL.

Letter: Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Systematic Review and Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines.

To the Editor: We read with interest the article by Singh et al1 synthesizing the modern literature around the use of stereotactic radiosurgery (SRS) in the treatment of cranial dural arteriovenous fistulas (DAVFs). Neurointervention has disrupted the established treatment paradigm for many neurosurgical conditions. From intracranial aneurysms and large vessel occlusions to hydrocephalus, neuroendovascular surgery favorably altered the natural history and reduced the treatment-related morbidity of these and other disease processes. This has changed the mindset of clinicians who treat patients with cerebrovascular disease. For instance, a patient with an unruptured wide-necked aneurysm may be better served with an endovascular treatment that leaves a small neck remnant than with clip reconstruction that affords complete occlusion but requires a considerably more invasive surgical approach. Endovascular therapy has, in a generally safe and minimally invasive fashion, lowered the clinical risk of many pathologies without affording complete cure. In light of the available literature, a similar shift in mindset may be warranted regarding SRS for the treatment of cranial DAVFs. Just as SRS met with initial skepticism regarding its efficacy for vestibular schwannomas,2 neurointerventionalists and cerebrovascular surgeons have been slow to embrace its utility for DAVFs.3 In recent years, mounting evidence has emerged to support the efficacy of SRS as more than just a salvage therapy after failed endovascular embolization of DAVFs.4,5 In light of this, a recent systematic review and meta-analysis by Singh et al1 on behalf of the International Stereotactic Radiosurgery Society has summarized the DAVF SRS outcomes and provided some practice guidelines. In their analysis of 705 SRS-treated patients with DAVF in 21 studies, the authors reported complete occlusion and symptomatic cure rates of nearly 70% and 80%, respectively.1 In comparison, a recent meta-analysis of transarterial DAVF embolization using ethylene vinyl alcohol copolymer (Onyx; Medtronic Neurovascular) reported a complete occlusion rate of 82%.6 A multicenter retrospective analysis of the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database reported a complete obliteration rate of 55% after initial Onyx embolization.7 In this CONDOR study, the final obliteration rate with Onyx was less than 70%, even after all treatments. Surgical DAVF series typically report a higher obliteration rates than endovascular series, but many of these surgical cases have failed endovascular therapy, and operative morbidity and mortality rates up to 17% have been reported.3,8,9 The rates of post-SRS hemorrhage and permanent neurological deficits reported by Singh et al1 in their meta-analysis were 1.1% and 1.3%, respectively. By comparison, the risk of permanent neurological deficit after DAVF embolization was 4% in the meta-analysis by Sadeh-Gonike et al6 and 16.1% in the CONDOR database.7 In a separate analysis of unruptured high-grade DAVFs from CONDOR, post-treatment hemorrhage rates in the observation, endovascular, surgical, and SRS groups were 6.9%. 1.6%, 2.3%, and 0%, respectively.4 Although there were relatively few patients in the SRS group (n = 19), the risk of post-treatment hemorrhage seems to be similar among the various therapeutic modalities for unruptured DAVFs. DAVFs can be rewarding lesions to address for neurointerventionalists, as they provide a satisfying combination of technical skill, anatomic knowledge, and innovative approaches (ie, transvenous, direct puncture, combined surgical and endovascular). However, these cases can require hours of radiation exposure for the patient over potentially multiple embolization sessions, and there is a modest risk of DAVF recurrence even after initial angiographic cure. Based on analyses of the CONDOR database, obliteration of a low-grade DAVF after a single embolization session was achieved in <40% of cases,10 and the rate of recurrent arteriovenous shunting after angiographic cure (which required a mean of >2 embolization sessions) was 7%.11 Based on these findings, SRS may warrant consideration as a first-line treatment for unruptured DAVFs.1 If patients understand the potential risks associated with the latency period between treatment and efficacy, SRS should be discussed with unruptured patients with DAVF as a viable and reasonable alternative to embolization and surgical ligation. Definitive evidence from randomized comparative trials among the various treatment strategies for DAVFs is unlikely to be forthcoming for such a rare condition. Therefore, we will continue to rely on large multicenter databases, such as CONDOR, for our best available evidence regarding management outcomes and complications in contemporary neurovascular practice. The practice guidelines put forth by the ISRS underscore the favorable risk to benefit profile of SRS for appropriately selected DAVFs.

An Overview of the Role of Radiotherapy in the Treatment of Small Cell Lung Cancer – A Mainstay of Treatment or a Modality in Decline?

AimsSmall cell lung cancer (SCLC) accounts for about 15% of all lung cancers. Chemotherapy, immunotherapy and radiotherapy all play important roles in the management of SCLC. The aim of this study was to provide a comprehensive overview of the role and evidence of radiotherapy in the cure and palliation of SCLC. Materials and methodsThe search strategy included a search of the PubMed database, hand searches, reference lists of relevant review articles and relevant published abstracts. ClinicalTrials.gov was also queried for relevant trials. ResultsThoracic radiotherapy improves overall survival in limited stage SCLC, but the timing and dose remain controversial. The role of thoracic radiotherapy in extensive stage SCLC with immunotherapy is the subject of several ongoing trials. Current evidence supports the use of prophylactic cranial irradiation (PCI) for limited stage SCLC but the evidence is equivocal in extensive stage SCLC. Whole brain radiotherapy is well established for the treatment of brain metastases but evidence is rapidly accumulating for the use of stereotactic radiosurgery. Further studies will define the role of PCI, whole brain radiotherapy and hippocampal avoidant PCI in the immunotherapy era. ConclusionRadiotherapy is an essential component in the multimodality management of SCLC. Technological advances have allowed safer delivery of radiotherapy with reduced toxicities. Discussion at multidisciplinary team meetings is important to ensure radiotherapy is considered and offered in appropriate patients.

STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES IN A CHILD WITH EXTRA-SKELETAL EWING'S SARCOMA

Ewing's sarcoma is the second most common oncological disease of bones and soft tissues in children and adolescents, which is characterized by rapid growth and early metastasis. Brain metastases (BMs) occur in 10–12 % of cases and constitute a factor in the unfavorable prognosis of the disease. The possibilities of surgical treatment are often limited by the localization of a metastatic tumor, and the vast majority of chemotherapy drugs don’t penetrate the blood-brain barrier, therefore radiation therapy, particularly stereotactic radiosurgery, the principle of which is a single high dose (15–24 Gy) of ionizing radiation to the pathological focus, is the most important method of treatment. High accuracy of tumor irradiation is ensured by rigid immobilization of the patient (using stereotactic frames or individual three-layer thermoplastic masks) in combination with positioning of the patient and control of his position by orthogonal X-rays. According to various authors, the use of stereotactic radiosurgery provides local control over BMs in 90 % of patients, regardless of the histological type of the primary focus, age and gender of the patient. The article describes a clinical case of successful radiosurgical treatment of a child suffering from extra-skeletal Ewing’s sarcoma, in which following the complex treatment, progression of the disease, represented by multiple metastatic brain damage was revealed; the cumulative volume of metastatic foci was 2.3 cm 3 and due to the proximity of the brain stem, as well as in order to avoid exceeding the tolerant load on healthy brain tissues, the total focal dose did not exceed 16 Gy. A complete response to therapy in the form of regression of all foci was noted six months after the treatment. To date, insufficient data has been published on the use of stereotactic radiosurgery in pediatric oncology, but in the available literature, the authors demonstrate the effectiveness and safety of treatment. Further research is needed to study the effect of the radiosurgical method on the children.

The Effect of Race in the Palliative Treatment of Bone Metastases

PurposePrior studies demonstrated that single and multiple-fraction radiation therapy (RT) provide comparable pain relief in palliative-care patients. In addition, unconscious racial biases may affect practice patterns in oncology. In this study, we examined the effect of race on the duration of RT for palliative treatment of bone metastases. Methods and MaterialsThis is a retrospective study of 707 patients treated for bone metastases between 2013 and 2020 (1348 treatments). Patient race, demographics, RT dose, number of fractions, use of stereotactic radiosurgery (SRS), and performance score were collected. A short-course was defined as a single fraction, whereas a long-course was defined as more than one fraction. SRS cases were analyzed separately. ResultsOf all nonradiosurgery RT treatments delivered, 28.9% were single fraction and 71.1% were multiple fraction. In total, 76% of the patients were White and 24% were non-White. With regard to race, the number of White patients receiving short- and long-course RT was 256 (27.9%) and 663 (72.1%), respectively. The number of non-White patients receiving short- and long-course RT was 97 (31.9%) and 207 (68.1%), respectively. There was no difference in treatment duration based on patient race (P = .20). The use of SRS did not vary based on race (P = .79). There was no statistically significant difference in Karnofsky Performance Status Scale score between White and non-White patients (P = .44). ConclusionsAnalysis of patient and physician characteristics revealed that race did not influence treatment decisions such as duration of palliative RT regimen or use of SRS. Although palliative-care regimens must be individualized for each patient, such investigations can identify potential biases in treatment decisions.

The immediate results of choroidal melanoma treatment using stereotactic radiosurgery

The aim of this study was to evaluate the immediate results of the stereotactic radiosurgery (SRS) application in patients with choroid melanoma.Material and methods. The prospective study included 43 patients who were diagnosed with choroidal melanoma cT1–3N0M0.SRS was performed on a Gamma Knife gamma therapeutic unit, Perfexion (Elekta, Sweden). Under local anesthesia, the eyeball was immobilized using frenulum sutures on the rectus muscles. The median prescribed dose per tumor margin at 50% isodose was 30 Gy. The immediate effect of the treatment was assessed as positive (local control) in all cases, except increased blood flow according to Doppler ultrasound, an increase in tumor size by more than 20% of the previously determined lesion according to MRI.Results. During the follow-up period (median follow-up — 16 months), there were no cases of negative outcome in terms of local tumor control.A statistically significant gradual decrease in tumor thickness was revealed during the entire observation period (6.6±2.1 mm before treatment, 5.3±2.1 mm 12 months after treatment, p&lt;0.001), stabilization of the tumor base (12.25±3.26 mm before treatment, 11.4±2.5 mm 12 months after treatment, p=0.355). Contrast-enhanced MRI also showed a progressive statistically significant decrease in tumor volume (635.21±328.32 mm3 before treatment, 376.0±267.6 mm3 15 months after treatment, p&gt;&lt;0.001). The eyeball was saved in 90.1%. Post-radiation optical retinopathy developed in 9.3% of &gt;˂0.001), stabilization of the tumor base (12.25±3.26 mm before treatment, 11.4±2.5 mm 12 months after treatment, p=0.355). Contrast-enhanced MRI also showed a progressive statistically significant decrease in tumor volume (635.21±328.32 mm3 before treatment, 376.0±267.6 mm3 15 months after treatment, p&lt;0.001). The eyeball was saved in 90.1%. Post-radiation optical retinopathy developed in 9.3% of&gt;˂0.001). The eyeball was saved in 90.1%. Post-radiation optical retinopathy developed in 9.3% of cases, progression of retinal detachment was registered in 13.9% of cases. The one-year metastatic-free survival rate was 96.3±3.6%, the two-year survival rate was 81.3±8.6%.Conclusions. In the present study, the use of stereotactic radiosurgery with a prescribed marginal dose of up to 35 Gy allowed achieving sustainable local control of primary choroidal melanoma cT1–3 in 100% of cases over a median follow-up period of 16 months.

Stereotactic radiosurgery for secretory pituitary adenomas: systematic review and International Stereotactic Radiosurgery Society practice recommendations.

A systematic review was performed to provide objective evidence on the use of stereotactic radiosurgery (SRS) in the management of secretory pituitary adenomas and develop consensus recommendations. The authors performed a systematic review of the English-language literature up until June 2018 using the PRISMA guidelines. The PubMed (Medline), Embase, and Cochrane databases were searched. A total of 45 articles reporting single-institution outcomes of SRS for acromegaly, Cushing's disease, and prolactinomas were selected and included in the analysis. For acromegaly, random effects meta-analysis estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rates were 97.0% (95% CI 96.0%-98.0%), 44.0% (95% CI 35.0%-53.0%), and 17.0% (95% CI 13.0%-23.0%), respectively. For Cushing's disease, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 92.0% (95% CI 87.0%-95.0%), 48.0% (95% CI 35.0%-61.0%), and 21.0% (95% CI 13.0%-31.0%), respectively. For prolactinomas, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 93.0% (95% CI 90.0%-95.0%), 28.0% (95% CI 19.0%-39.0%), and 12.0% (95% CI 6.0%-24.0%), respectively. Meta-regression analysis did not show a statistically significant association between mean margin dose with crude endocrine remission rate or mean margin dose with development of any new hypopituitarism rate for any of the secretory subtypes. SRS offers effective tumor control of hormone-producing pituitary adenomas in the majority of patients but a lower rate of endocrine improvement or remission.

A novel treatment for malignant spasticity: The therapeutic use of stereotactic radiosurgery (SRS)

Spasticity is a clinical condition secondary to central nervous system damage, which impairs patients’ mobility and quality of life. Stereotactic radiosurgery (SRS) to the spinal roots responsible of the spasms might represent a non-invasive therapy. The present are the preliminary results of the first clinical use of this novel technique.

Review of the diagnosis and treatment of brain metastases.

Brain metastases (BM) occur in at least 10% of cancer patients, and are one of the main causes of cancer-related deaths and significant deterioration in the quality of life of cancer patients due to the neurological deterioration caused by brain compression and tumor invasion. Whole-brain irradiation has been emphasized as the standard treatment for BM. However, recent clinical trials including the JLGK0901 and JCOG0504 trials conducted in Japan have established therapeutic evidence for the use of stereotactic radiosurgery with regular follow-up with magnetic resonance imaging for BM. In addition to surgery and stereotactic radiotherapy, advances in drug therapy for BM, such as tyrosine kinase inhibitors and immune checkpoint inhibitors, are expected. This review describes the history and the recent evidence of the diagnosis and treatment of BM.

RADT-11. INCREASED USE OF HYPOFRACTIONATED RADIOTHERAPY IN ELDERLY PATIENTS WITH GLIOBLASTOMA IN THE UNITED STATES FROM 2004-2015

Abstract PURPOSE/OBJECTIVES The prognosis for glioblastoma in elderly patients is poor; randomized trials have demonstrated comparable survival following adjuvant radiotherapy (RT) using conventional or hypofractionation. We used the National Cancer Database (NCDB) to measure trends in the use of hypofractionated RT in glioblastoma patients 70 years of age and older. MATERIALS AND METHODS The NCDB was queried for elderly glioblastoma patients treated with a known RT dosing schema from 2004-2015 (n=10,089 patients). Adjusted logistic regression was used to assess the association of treatment year with the annual percentage of patients who received hypofractionated RT (including 40-45 Gy/15 fractions, 34 Gy/10 fractions, or 25 Gy/5 fractions). Average annual percentage change (AAPC) was compared to determine if a significant change occurred in the use of hypofractionated RT during this period. Multivariable regression was used to determine factors associated with the use of hypofractionated RT. RESULTS Use of hypofractionated RT was stable between 2.5-3.3% from 2004-2008 and then monotonically increased to 22.2% by 2015 (p&amp;lt; 0.001). The AAPC in the use of hypofractionated RT was +29.6% per year (p&amp;lt; 0.001), with a corresponding decline in conventional fractionation over this period. No significant change was observed in palliative dosing schema or the use of stereotactic radiosurgery. On logistic regression, age, treatment at an academic center, Charlson Deyo score ≥2, and treatment year were significantly associated with utilization of hypofractionated RT. In this dataset, 24.8% of patients who received either conventional or hypofractionated RT died within 3 months of beginning RT. CONCLUSIONS During 2008-2015, an increasing number of elderly patients with glioblastoma received hypofractionated RT. Hypofractionated RT should be considered in elderly patients to shorten the time spent receiving medical care during the final months of life. Attention to hospice care is also important, especially in those with brief expected survival who may derive limited benefit from RT.

RADT-05. PROSPECTIVE LONG-TERM EVALUATION OF MRI- AND CLINICAL CHANGES FOLLOWING STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES – IS REPEAT SRS A CONSEQUENCE, OR ALSO A CAUSE OF LONG-TERM SURVIVAL?

Abstract The use of stereotactic radiosurgery (SRS) for brain metastases are increasing. Response assessment is challenging and the clinical significance of radiological response and retreatments are poorly defined. Ninety-seven patients with a total of 406 brain metastases were followed prospectively for 10 years or until death. Volume changes over time and clinical outcome in response to first time SRS and SRS retreatments were analyzed. Tumors grew significantly before (p = 0.004), but shrunk at 1 and 3 months (p = 0.001) following SRS. Four response-patterns of were observed; tumors either continuously reduced in size (A, 62%), pseudo-progressed (PP, B, 13%), temporarily reduced in size (C, 24%), or grew continuously (D, 2%); corresponding to 75% local control (LC) at initial SRS. Predictors for LC were primary cancer site (p = 0.001), tumor volume (p = 0.002) and target cover ratio (p = 0.005). Subsequent SRS for new lesions resulted in 94% LC (87% A) and repeat-SRS for local failures in 80% LC (57% B), predicted by higher prescribed dose, p = 0.001 and p = 0.042, respectively. Overall survival was only 4.5 months if A-response for all lesions, 13.3 months if at least one B-response, 17.1 months if retreated C- or D-response (p &amp;lt; 0.001), (7.5 and 4.7 months if untreated). Quality of life (p = 0.003), steroid use (p = 0.019) and prior whole brain radiotherapy (p = 0.026) were predictors for survival. There are 4 response patterns to SRS predicted by tumor size, primary cancer site, target cover ratio and prescribed dose. Long-term survivors experienced a higher incidence of PP and were more often retreated for new lesions and local failures. The immune response induced by PP seems beneficial but further studies are needed.

Experimental use of stereotactic radiosurgery for non-invasive interventions in arrhythmology

Purpose. The experimental study aimed to study the effects of stereotaxic radioablation of various doses on the myocardium of the atria, ventricles and atrioventricular (AV) node in the long term (up to 6 months); as well as assessment of collateral damage during radioablation.Methods. The study comprised 4 domestic pigs. The animals were 10-12 weeks old, the average weight was 30±2.7 kg. A linear accelerator was used for the experiment. Each animal underwent radiation exposure in different areas: 1st animal - AV node (dose 35 Gy), 2nd animal - AV node and the apex of the left ventricle (LV) (dose 40/35 Gy, respectively), 3rd animal - pulmonary veins (PV) and left atrium (dose 30 Gy), 4th - AV node and LV free wall (dose 45/40 Gy). Under intravenous sedation with hemodynamic monitoring, contrast-based CT of the heart was performed to assess the degree of displacement of the heart chambers in one respiratory and cardiac cycle and to assess the anatomy of the chambers of the heart and adjacent organs. The allocation and the contouring of the target zones were carried out in three projections: axial, frontal and sagittal. For electrocardiographic control, a loop recorder was implanted in each animal. The average exposure time was 11±7 minutes. After a follow-up period, morphological examination of the autopsy material was performed.Results. The average follow-up period after ablation was 134.75±77.34 days. The electrophysiological effect of the ablation was achieved in cases of complete AV-block development. This effect was developed in 2 out of 3 animals, where AV-node was exposed: 2nd animal - 40 Gy on 108th day of observation and 4th animal - 45 Gy on 21st day of observation. No cardiac tachyarrhythmia was recorded in the animals. The results of myocardium macro- and microscopic examination showed significant changes in the target zones. These areas had precise but uneven damage boundaries, which were within the planned ones (conformal exposure with a high degree of precision). The transmural nature of the changes was noted as well. Massive fields of fibrous tissue of various degrees of maturity (with a predominance of subepicardial localization) with focal hemorrhages of various ages and granulations were detected, which were surrounded by cardiomyocytes with coagulated and vacuolated cytoplasm.Conclusion. The use of non-invasive stereotactic treatment of tachyarrhythmias has high prospects in modern electrophysiology as an alternative ablation method.

Stereotactic Radiosurgery (SRS) for Spinal Metastatic Disease: Outcomes From the RSSearch Patient Registry

While increasing evidence supports the use of stereotactic radiosurgery (SRS) for oligometastatic spinal disease, there is mixed prospective evidence on its effectiveness for pain compared to conventional radiation therapy and limited evidence to guide optimal patient selection in the setting of asymptomatic disease.A prospectively maintained multi-institutional registry was queried for patients with spinal metastatic disease treated with single-fraction SRS (SF-SRS) or fractionated SRS (MF-SRS). Potential predictive factors of local control (LC) and overall survival (OS) were evaluated. Pre-treatment and post-treatment visual analog scores (VAS) were analyzed to examine both initial and durable pain responses in addition to complete response (CR) rates with patients with VAS scores < 3 excluded from analysis. Logistic regression was utilized to examine potential correlations between pain response, fractionation, and prescription dose.Four-hundred and sixty-eight patients were identified with 514 lesions treated with SRS. Median follow-up was 8.8 months (range: 0.4-89.7). Median patient age was 65 years, median KPS was 80%, and the median gross tumor volume (GTV) was 30.6cc. The median pain score of patients initially with symptoms was 6 (range: 3-10). The median biologically effective dose (BED10) and dose/fraction were 50.4 Gy10 and 10 Gy, respectively, with 99 patients treated with SF-SRS. Common primary locations included the lung (25.4%), breast (18.1%), kidney (10.5%), and prostate (9.2%). One- and 2-year OS rates were 53.4% and 33.6%, respectively. Utilizing KPS, age, and primary site (lung and/or non-breast), 1-year OS rates were 76.1%, 59.1%, 54.9%, 37.2%, and 23.5%, for patients with 0-4 of these factors, respectively (P < 0.0001). One- and 2-year LC rates were 79.9% and 73.6%, respectively, with no difference in LC between SF- and MF-SRS. Eighty-six patients (82.7%) had an initial decline in pain scores with a median decline of 3.5 and a CR rate of 47.1% (SF-SRS: 47.6% vs. MF-SRS: 47.0%). At last follow-up, 65 patients (62.5%) had a durable decline in pain scores with a median decline in pain score of 2 and a CR rate of 20.2% (SF-SRS: 28.6% vs. MF-SRS: 18.2%; P = 0.29). No significant difference in either initial (P = 0.30) or durable pain scores of < 3 (P = 0.31) or < 4 (P = 0.56) was found between SF-SRS vs. MF-SRS.Patients with spinal metastases treated with SRS had encouraging palliative responses. Greater than 80% of patients had an initial pain response and close to 50% an initial CR with durable pain response achieved for roughly 60% of patients. Performance status, age, and primary histology (lung and or/breast) are prognostic factors to consider when determining suitability for SRS in the absence of pain.

Long-Term Hearing Outcomes From Gamma Knife Treatment for Vestibulocochlear Nerve Schwannomas in a Large, Tertiary Care, Academic Hospital.

Describe long-term hearing outcomes with audiologic data with modern stereotactic radiosurgery techniques for vestibular schwannoma tumors. Since the mid-20th century, stereotactic radiosurgery has been an option for central nervous system tumors. Due to the non-invasive manner of treatment, this was extended to treatment for benign vestibular schwannomas without intracranial surgery. Modern advances have localized radiation and reduced dosage, but data are still lacking in the long-term hearing outcomes of this method of treatment. As one of the national leaders in this procedure, we present our full database of these outcomes over the full time period of our institutions utility of this modality. A retrospective review was performed of all patients undergoing stereotactic radiotherapy for vestibular schwannomas within the study period of 1998 to 2019 and their audiograms analyzed along with patient data. Laterality Gardner-Robertson hearing score changes were the primary outcome analyzed for each patient; and controls were placed to accommodate for patient demographic data. Long-term, multi-year audiometric evaluation showed statistically significant loss of serviceable hearing and reduction in hearing ability with the use of stereotactic radiosurgery for treatment of vestibular schwannomas. Little long-term data exists on the audiometric outcomes related to stereotactic radiosurgery treatment for vestibular schwannomas. Our institution has performed more than 300 stereotactic radiosurgery treatments showing a continued reduction over time in serviceable hearing. Practitioners should advise patients undergoing treatment for vestibular schwannomas with this treatment of long-term results.