The NeuroPoint alliance SRS & tumor QOD registries.

OBJECTIVE: Along with the increasing interest in real-world evidence in neuro-oncology, the deficiencies of prior population-based and quality registries became evident. The neuro-oncological quality registries of the NeuroPoint Alliance (NPA) focus on neuro-oncological surgery and stereotactic radiosurgery (SRS) and aim to fill the gaps of neuro-oncological practice in quality surveillance and real-world research. METHODS: Herein, we discuss the historical background, design process, and features of the NPA SRS and Tumor QOD registries. The registries'current status and future directions are outlined. RESULTS: The NPA SRS and Tumor QOD registries were designed based on the principles of prospective multi-institutional data collection, central auditing for data quality, and focus on patient-reported outcomes (PROs). Currently, the registries include over 4,500 and 2,500 patients each, with caseloads comprising predominantly of brain metastases and primary extra-axial tumors, respectively. The registries serve both as a quality surveillance and improvement tool - providing participating sites with adjusted quality reports - and as platforms for real-world research of observational and, potentially, interventional nature. Future directions of the NPA neuro-oncological registries include the functional communications of the two registries and the incorporation of imaging analyses in the workflow of quality assessment and research efforts. CONCLUSIONS: The NPA SRS and Tumor QOD registries are quality registries of unique granularity in terms of surgical variables and postoperative outcomes. They constitute increasingly valuable data sources for real-time quality surveillance of participating sites and real-world research.

Stereotactic radiosurgery for intracranial cavernous malformations of the deep-seated locations: systematic review and meta-analysis.

OBJECTIVE: To determine the outcomes of stereotactic radiosurgery (SRS) for deep-seated (brainstem, basal ganglia, thalamus, cerebellar peduncle) intracranial cavernous malformations (ICMs). METHODS: A systematic review and meta-analysis was performed according to PRISMA and MOOSE guidelines. The main outcomes were comparing pre- and post-SRS hemorrhage rates, using the pooled risk ratios (RR) as the measure of effect. Additionally, the study assessed lesion volume changes and radiation-injury incidence. RESULTS: Data of 850 patients across 14 studies were included in the meta-analysis. The pooled RR of all deep-seated ICMs show a decrease in hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.22), and after 2 years (RR =0.07). For 9 studies that reported hemorrhage rate of the brainstem only, the pooled RR shows a decrease of hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.19), and after 2 years (RR =0.07). Volumetric regression was achieved in 44.25% and stability in 56.1%. The pooled incidence of symptomatic and permanent radiation injury was 9% (95% CI, 7-11) and 3% (95% CI, 0-1.9%), respectively. CONCLUSION: SRS appears effective in reducing hemorrhage rates for deep-seated ICMs. The risk of symptomatic radiation injury is low. Given the high risk of surgical morbidity, SRS is a reasonable treatment option for patients with deep-seated ICMs with at least one prior hemorrhage.

Repeat single-session stereotactic radiosurgery for arteriovenous malformation: a systematic review and meta-analysis.

BACKGROUND: Stereotactic radiosurgery is the preferred option for treating brain arteriovenous malformation (AVM) when the risks associated with surgery outweigh the potential benefits. However, some patients require repeat radiosurgery due to residual AVM after the first procedure. This systematic review and meta-analysis aimed to investigate the safety and efficacy of repeated procedure of radiosurgery for AVM. METHOD: A systematic review was conducted according to the PRISMA guideline. The search was conducted on PubMed, Scopus, Embase, and Web of Science, using a pre-designed search string. Studies investigating the efficacy of repeat radiosurgery for residual AVM following initial single session radiosurgery were included. The risk of bias was assessed using the JBI tool. Meta-analysis and met-regression were performed to pool and inspect data. RESULTS: Our meta-analysis, with a mean follow-up of 45.57 months, reveals repeat radiosurgery as a viable option for arteriovenous malformations (AVMs), achieving a 60.82% obliteration rate with a mean time to obliteration of 33.18 months. Meta-regression identifies AVM volume and Spetzler-Martin (SM) grade as factors influencing obliteration, with smaller volume and lower SM grades associated with higher rates. Complications include 10.33% radiation-induced changes, 5.26% post-radiosurgery hemorrhage, 2.56% neurologic deficits, and 0.67% cyst formation. Heterogeneity in complications is primarily attributed to male proportion and SM grade, while factors influencing post-radiosurgery hemorrhage remain unclear. The type of radiosurgery, whether Gamma Knife Radiosurgery (GKRS) or LINAC, does not significantly impact outcomes. CONCLUSION: Repeat radiosurgery is a feasible, effective, and safe treatment for AVMs following failure of initial radiosurgery. When utilized in appropriate patient subgroups, it provides an acceptable risk-to-benefit profile. Feature studies are required to clarify its clear indications.

Stereotactic radiosurgery in the management of skull base chordomas: a comprehensive systematic review and meta-analysis.

OBJECTIVE: Chordoma is a primary bone tumor with limited literature on its management because of its rarity. Resection, while considered the first-line treatment, does not always provide adequate tumor control. In this systematic review, the authors aimed to provide comprehensive insights by managing these tumors with stereotactic radiosurgery (SRS). METHODS: A systematic review was conducted according to PRISMA guidelines using the PubMed, Scopus, Web of Science, Embase, and Cochrane Library databases. Search terms included chordoma and radiosurgery and their equivalent terms. Data on baseline characteristics, SRS details, and outcomes were extracted. The Joanna Briggs Institute checklist was used to assess risk of bias. A meta-analysis was performed on relevant variables. RESULTS: A total of 33 eligible studies encompassing 714 patients with skull base chordomas were included. Most studies had a low risk of bias. Patients, predominantly male (57.37%) with a mean age of 46.54 years, exhibited a conventional chordoma subtype (74.77%) and primary lesions (77.91%), mainly in the clivus (98.04%). The mean lesion volume was 13.49 cm3, and 96.68% of patients had undergone prior surgical attempts. Gamma Knife radiosurgery (88.76%) was the predominant SRS method. Radiologically, 27.19% of patients experienced tumor regression, while 55.02% showed no signs of disease progression at the latest follow-up. Progression occurred after a mean of 48.02 months. Symptom improvement was noted in 27.98% of patients. Radiosurgery was associated with a relatively low overall adverse event rate (11.94%), mainly cranial nerve deficits (8.72%). Meta-regression revealed that age and primary lesion type influenced symptom improvement, while factors like extent of resection, radiotherapy, and SRS type affected adverse event rates. CONCLUSIONS: This systematic review provides evidence on the safety and effectiveness of radiosurgery in the management of skull base chordomas. Local tumor control was achieved in the majority of patients treated with SRS. Various baseline characteristics and SRS features have been analyzed to identify modifying factors for each outcome to provide a framework for informed decision-making when managing these patients.

Stereotactic radiosurgery with versus without embolization for intracranial dural arteriovenous fistulas: a systematic review and meta-analysis.

OBJECTIVE: Stereotactic radiosurgery (SRS) has been established as a safe and alternative treatment for dural arteriovenous fistulas (dAVFs). While embolization alone is the most commonly used modality for the treatment of dAVFs, the adjunctive use of embolization with SRS, with the growing use of SRS, has gained increasing interest in the past few years. However, the relative efficacy and safety of SRS combined with embolization versus SRS alone for dAVFs remains uncertain. Hence, this systematic review aimed to evaluate the efficacy of SRS with adjunctive embolization for intracranial dAVFs. METHODS: A systematic review and meta-analysis was conducted by searching electronic databases, including PubMed, Embase, and the Cochrane Library, up to August 2023. All studies evaluating the utilization of adjunctive embolization and SRS for dAVFs were included. Risk of bias was assessed using the Newcastle-Ottawa Scale. A meta-analysis was conducted on the suitable outcomes. RESULTS: Eighteen studies involving 715 patients were included. The mean age of the participants in the study was 64.30 years in the adjunctive embolization group and 60.51 years in the SRS-alone group. In the adjunctive embolization group 41.3% of patients were female, compared with 47.1% in the SRS-only group. The dAVF obliteration rates were 64.7% and 65.7% in the adjunctive embolization and SRS-alone groups, respectively. These obliteration rates were comparable between the two groups (p = 0.96), as were the symptom improvement rates (p = 0.35). Adverse events were rare, and were more commonly associated with the adjunctive embolization procedure, although further causal analysis was not possible. CONCLUSIONS: This study provides evidence that adjunctive embolization plus SRS provides similar obliteration and symptom improvement rates compared with SRS alone, with both having very limited SRS-related adverse events. Considering the added burden and adverse events of additional endovascular treatment, the authors recommend embolization be reserved for more complex dAVFs or when embolization can potentially be curative alone or provide more rapid symptomatic relief or protection during the radiosurgical latency period.

Dural arteriovenous fistulas are not observed to convert to a higher grade after partial embolization.

OBJECTIVE: Borden-Shucart type I dural arteriovenous fistulas (dAVFs) lack cortical venous drainage and occasionally necessitate intervention depending on patient symptoms. Conversion is the rare transformation of a low-grade dAVF to a higher grade. Factors associated with increased risk of dAVF conversion to a higher grade are poorly understood. The authors hypothesized that partial treatment of type I dAVFs is an independent risk factor for conversion. METHODS: The multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research database was used to perform a retrospective analysis of all patients with type I dAVFs. RESULTS: Three hundred fifty-eight (33.2%) of 1077 patients had type I dAVFs. Of those 358 patients, 206 received endovascular treatment and 131 were not treated. Two (2.2%) of 91 patients receiving partial endovascular treatment for a low-grade dAVF experienced conversion to a higher grade, 2 (1.5%) of 131 who were not treated experienced conversion, and none (0%) of 115 patients who received complete endovascular treatment experienced dAVF conversion. The majority of converted dAVFs localized to the transverse-sigmoid sinus and all received embolization as part of their treatment. CONCLUSIONS: Partial treatment of type I dAVFs does not appear to be significantly associated with conversion to a higher grade.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia.

OBJECTIVE: Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date. METHODS: We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM. RESULTS: Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08-0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I-II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25-44.4) and 20 (IQR 18-22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17-39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC. CONCLUSIONS: Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

Outcome Evaluation of Repeat Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations.

BACKGROUND: Repeat stereotactic radiosurgery (SRS) for persistent cerebral arteriovenous malformation (AVM) has generally favorable patient outcomes. However, reporting studies are limited by small patient numbers and single-institution biases. The purpose of this study was to provide the combined experience of multiple centers, in an effort to fully define the role of repeat SRS for patients with arteriovenous malformation. METHODS: This multicenter, retrospective cohort study included patients treated with repeat, single-fraction SRS between 1987 and 2022. Follow-up began at repeat SRS. The primary outcome was a favorable patient outcome, defined as a composite of nidus obliteration in the absence of hemorrhage or radiation-induced neurological deterioration. Secondary outcomes were obliteration, hemorrhage risk, and symptomatic radiation-induced changes. Competing risk analysis was performed to compute yearly rates and identify predictors for each outcome. RESULTS: The cohort comprised 505 patients (254 [50.3%] males; median [interquartile range] age, 34 [15] years) from 14 centers. The median clinical and magnetic resonance imaging follow-up was 52 (interquartile range, 61) and 47 (interquartile range, 52) months, respectively. At last follow-up, favorable outcome was achieved by 268 (53.1%) patients (5-year probability, 50% [95% CI, 45%-55%]) and obliteration by 300 (59.4%) patients (5-year probability, 56% [95% CI, 51%-61%]). Twenty-eight patients (5.6%) experienced post-SRS hemorrhage with an annual incidence rate of 1.38 per 100 patient-years. Symptomatic radiation-induced changes were evident in 28 (5.6%) patients, with most occurring in the first 3 years. Larger nidus volumes (between 2 and 4 cm3, subdistribution hazard, 0.61 [95% CI, 0.44-0.86]; P=0.005; >4 cm3, subdistribution hazard, 0.47 [95% CI, 0.32-0.7]; P<0.001) and brainstem/basal ganglia involvement (subdistribution hazard, 0.6 [95% CI, 0.45-0.81]; P<0.001) were associated with reduced probability of favorable outcome. CONCLUSIONS: Repeat SRS confers reasonable obliteration rates with a low complication risk. With most complications occurring in the first 3 years, extending the latency period to 5 years generally increases the rate of favorable patient outcomes and reduces the necessity of a third intervention.

Social media insights for neurosurgical oncologists: a survey of the American Association of Neurological Surgeons and Congress of Neurological Surgeons Joint Section on Tumors.

PURPOSE: There is a paucity in the literature regarding the characteristics and attitudes of social media (SM) utilization in a professional manner by neurosurgical oncologists. METHODS: A 34-question electronic survey was created using Google Forms and disseminated via email to members of the AANS/CNS Joint Section on Tumors. Demographic data were compared amongst those who utilize social media versus those who do not. Factors associated with positive effects of professional SM use and with having more followers on SM were analyzed. RESULTS: The survey received 94 responses, of which 64.9% reported that they currently use SM in a professional manner. Age < 50 years was found to be associated with SM use (p = 0.038). Facebook (54.1%), Twitter (60.7%), Instagram (41%), and LinkedIn (60.7%) were the most used SM platforms. Having a higher number of followers was associated with practicing in academics (p = 0.005), using Twitter (p = 0.013), posting about their own research publications (p = 0.018), posting interesting cases (p = 0.022), and posting about upcoming events (p = 0.001). Having a higher number of followers on SM was also associated with positive effects, specifically new patient referrals (p = 0.04). CONCLUSION: Neurosurgical oncologists can benefit by using social media professionally for increased patient engagement and networking within the medical community. Practicing in academics, making use of Twitter, and posting about interesting cases, upcoming academic events, and one's own research publications can help gain followers. In addition, having a large following on social media could lead to positive effects such as new patient referrals.

Preoperative stereotactic radiosurgery as neoadjuvant therapy for resectable brain tumors.

PURPOSE: Stereotactic radiosurgery (SRS) is a method of delivering conformal radiation, which allows minimal radiation damage to surrounding healthy tissues. Adjuvant radiation therapy has been shown to improve local control in a variety of intracranial neoplasms, such as brain metastases, gliomas, and benign tumors (i.e., meningioma, vestibular schwannoma, etc.). For brain metastases, adjuvant SRS specifically has demonstrated positive oncologic outcomes as well as preserving cognitive function when compared to conventional whole brain radiation therapy. However, as compared with neoadjuvant SRS, larger post-operative volumes and greater target volume uncertainty may come with an increased risk of local failure and treatment-related complications, such as radiation necrosis. In addition to its role in brain metastases, neoadjuvant SRS for high grade gliomas may enable dose escalation and increase immunogenic effects and serve a purpose in benign tumors for which one cannot achieve a gross total resection (GTR). Finally, although neoadjuvant SRS has historically been delivered with photon therapy, there are high LET radiation modalities such as carbon-ion therapy which may allow radiation damage to tissue and should be further studied if done in the neoadjuvant setting. In this review we discuss the evolving role of neoadjuvant radiosurgery in the treatment for brain metastases, gliomas, and benign etiologies. We also offer perspective on the evolving role of high LET radiation such as carbon-ion therapy. METHODS: PubMed was systemically reviewed using the search terms "neoadjuvant radiosurgery", "brain metastasis", and "glioma". ' Clinicaltrials.gov ' was also reviewed to include ongoing phase III trials. RESULTS: This comprehensive review describes the evolving role for neoadjuvant SRS in the treatment for brain metastases, gliomas, and benign etiologies. We also discuss the potential role for high LET radiation in this setting such as carbon-ion radiotherapy. CONCLUSION: Early clinical data is very promising for neoadjuvant SRS in the setting of brain metastases. There are three ongoing phase III trials that will be more definitive in evaluating the potential benefits. While there is less data available for neoadjuvant SRS for gliomas, there remains a potential role, particularly to enable dose escalation and increase immunogenic effects.

Single session versus multisession stereotactic radiosurgery for the management of intracranial meningiomas: a systematic review and meta-analysis.

PURPOSE: To compare the efficacy, outcomes, and complications of single session (SS-SRS) and multisession (MS-SRS) stereotactic radiosurgery in the treatment of intracranial meningiomas. METHODS: Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane. A systematic review and meta-analysis of treatment protocols and outcomes were conducted. After the selection process, 20 articles describing 1483 cases were included. RESULTS: A total of 1303 patients who underwent SS-SRS and 180 patients who underwent MS-SRS for the management of their intracranial meningioma were reported in the included studies. SS-SRS and MS-SRS had comparable one-year (SS-SRS: 98% vs. MS-SRS: 100%, p > 0.99) and five-year (SS-SRS: 94% vs. MS-SRS: 93%, p = 0.71) tumor control rates. The groups also had comparable tumor volume reduction/tumor regression rates (SS-SRS: 44% vs. MS-SRS: 25%, p = 0.25), tumor volume stability rates (SS-SRS: 51% vs. MS-SRS: 75%, p = 0.12), and tumor progression rates (SS-SRS: 4% vs. MS-SRS: 4%, p = 0.89). SS-SRS and MS-SRS yielded similar complication rates (10.4% vs. 11.4%, p = 0.68) and comparable functional improvement rates (MS-SRS: 44% vs. SS-SRS: 36%, p = 0.57). However, MS-SRS was used for significantly larger tumor volumes (MS-SRS: 23.8 cm3 vs. SS-SRS: 6.1 cm3, p = 0.02). CONCLUSION: SS-SRS and MS-SRS resulted in comparable tumor control, tumor volumetric change, and functional outcomes despite significant biases in selecting patients for SS- or MS-SRS.

Immune checkpoint inhibition and single fraction stereotactic radiosurgery in brain metastases from non-small cell lung cancer: an international multicenter study of 395 patients.

PURPOSE: Approximately 80% of brain metastases originate from non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICI) and stereotactic radiosurgery (SRS) are frequently utilized in this setting. However, concerns remain regarding the risk of radiation necrosis (RN) when SRS and ICI are administered concurrently. METHODS: A retrospective study was conducted through the International Radiosurgery Research Foundation. Logistic regression models and competing risks analyses were utilized to identify predictors of any grade RN and symptomatic RN (SRN). RESULTS: The study included 395 patients with 2,540 brain metastases treated with single fraction SRS and ICI across 11 institutions in four countries with a median follow-up of 14.2 months. The median age was 67 years. The median margin SRS dose was 19 Gy; 36.5% of patients had a V12 Gy ≥ 10 cm3. On multivariable analysis, V12 Gy ≥ 10 cm3 was a significant predictor of developing any grade RN (OR: 2.18) and SRN (OR: 3.95). At 1-year, the cumulative incidence of any grade and SRN for all patients was 4.8% and 3.8%, respectively. For concurrent and non-concurrent groups, the cumulative incidence of any grade RN was 3.8% versus 5.3%, respectively (p = 0.35); and for SRN was 3.8% vs. 3.6%, respectively (p = 0.95). CONCLUSION: The risk of any grade RN and symptomatic RN following single fraction SRS and ICI for NSCLC brain metastases increases as V12 Gy exceeds 10 cm3. Concurrent ICI and SRS do not appear to increase this risk. Radiosurgical planning techniques should aim to minimize V12 Gy.

Contemporary radiotherapy and radiosurgery techniques for refractory pituitary adenomas.

The pituitary gland is a potential site for a range of pathologies, for which treatment can involve resection and/or ionizing radiation. Modern stereotactic radiosurgery (SRS) involves highly conformal radiation, allowing for the delivery of high doses to the tumor while simultaneously sparing nearby healthy structures. SRS has become a standard treatment option for residual or recurrent pituitary adenomas. It has been used for both functioning and nonfunctioning pituitary adenomas, with reported local tumor control over 90% and moderate rates of endocrine remission in functioning adenomas. We aim to briefly review the existing indictions and supporting literature for the use of SRS for refractory adenomas.

Role of biological effective dose for prediction of endocrine remission in acromegaly patients treated with stereotactic radiosurgery.

PURPOSE: Stereotactic radiosurgery (SRS) can be used in acromegaly patients to achieve endocrine remission. In this study we evaluate the biological effective dose (BED) as a predictor of SRS outcomes for acromegaly. METHOD: This retrospective, single-center study included patients treated with single-fraction SRS with growth hormone secreting pituitary adenomas and available endocrine follow-up. Kaplan-Meier analysis was used to study endocrine remission, new pituitary deficit, and tumor control. Cox analyses were performed using two models [margin dose (model 2) versus BED (model 1)]. RESULTS: Sixty-seven patients (53.7% male) with a median age of 46.8 years (IQR 21.2) were treated using a median dose of 25 Gy (IQR 5), and a median BED of 171.9Gy2.47 (IQR 66.0). Five (7.5%) were treated without stopping antisecretory medication. The cumulative probability of maintained endocrine remission off suppressive medications was 62.5% [47.9-73.0] at 3 years and 76.5% [61.0-85.9] at 5 years. IGF1i > 1.5 was a predictor of treatment failure [Hazard ratio (HR) 0.40 (0.21-0.79) in model 1, p = 0.00783]. Margin dose > 22 Gy [HR 2.33 (1.06-5.13), p = 0.03593] or a BED > 170Gy2.47 [HR 2.02 (1.06-3.86), p = 0.03370] were associated with endocrine remission. The cumulative probability of new hypopituitarism after SRS was 36.8% (CI 95% 22.4-45.9) at 3 years and 53.2% (CI 95% 35.6-66) at 5 years. BED or margin dose were not associated with new hypopituitarism. CONCLUSION: BED is a strong predictor of endocrine remission in patients treated with SRS. Dose planning and optimization of the BED to > 170Gy2.47 give a greater probability of endocrine remission in acromegalic patients.

Prophylactic cranial irradiation effect on survival in patients with small cell lung cancer: a comprehensive systematic review and meta-analysis.

OBJECTIVE: Prophylactic cranial irradiation (PCI) is a companion treatment option for small cell lung cancer (SCLC) patients. However, its efficacy and associated risk factors have not been clearly defined. In this study, the authors aimed to systematically assess the effectiveness and role of PCI in the treatment plan of SCLC. METHODS: The PubMed, Scopus, Web of Science, and Cochrane databases were searched using the following key terms and their equivalents: "brain," "radiotherapy," "metastases," "prophylactic," and "small cell lung cancer." Studies comparing overall survival (OS), progression-free survival (PFS), brain metastasis-free survival (BMFS), and incidence of brain metastases between patients receiving PCI and those not receiving it were considered eligible. Risk of bias was assessed using the Risk of Bias in Non-Randomized Studies-of Interventions (ROBINS-I) tool. Meta-analysis was conducted on the mentioned outcomes with subgrouping based on different factors. RESULTS: The authors identified 74 studies published between 1983 and 2022 with 31,551 SCLC patients, of whom 26.7% received PCI. The studies were a mix of prospective randomized and retrospective observational studies. Patients with limited-stage disease receiving PCI had better OS, PFS, and BMFS than those not receiving PCI. Patients receiving PCI also had significantly longer OS times and developed brain metastases significantly later. However, findings regarding extensive-stage SCLC were not as promising. CONCLUSIONS: PCI is an effective option for limited-stage SCLC patients. It improves OS and PFS, delays brain metastases, and reduces the incidence of brain metastases. However, it might not benefit patients with extensive-stage SCLC under adequate follow-up with MRI surveillance. Finally, the heterogeneity of the included studies and publication bias were the main limitations of this study.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma in patients ≥ 65 years old: a multi-institutional retrospective study.

BACKGROUND: Surgery is the preferred treatment for large vestibular schwannomas (VS). Good tumor control and cranial nerve outcomes were described in selected Koos IV VS after single-session stereotactic radiosurgery (SRS), but outcomes in elderly patients have never been specifically studied. The aim of this study is to report clinical and radiological outcomes after single-session SRS for Koos IV VS in patients ≥ 65 years old. METHOD: This multicenter, retrospective study included patients ≥ 65 years old, treated with primary, single-session SRS for a Koos IV VS, and at least 12 months of follow-up. Patients with life-threatening or incapacitating symptoms were excluded. Tumor control rate, hearing, trigeminal, and facial nerve function were studied at last follow-up. RESULTS: One-hundred and fifty patients (median age of 71.0 (IQR 9.0) years old with a median tumor volume of 8.3 cc (IQR 4.4)) were included. The median prescription dose was 12.0 Gy (IQR 1.4). The local tumor control rate was 96.0% and 86.2% at 5 and 10 years, respectively. Early tumor expansion occurred in 6.7% and was symptomatic in 40% of cases. A serviceable hearing was present in 16.1% prior to SRS and in 7.4% at a last follow-up of 46.5 months (IQR 55.8). The actuarial serviceable hearing preservation rate was 69.3% and 50.9% at 5 and 10 years, respectively. Facial nerve function preservation or improvement rates at 5 and 10 years were 98.7% and 91.0%, respectively. At last follow-up, the trigeminal nerve function was improved in 14.0%, stable in 80.7%, and worsened in 5.3% of the patients. ARE were noted in 12.7%. New hydrocephalus was seen in 8.0% of patients. CONCLUSION: SRS can be a safe alternative to surgery for selected Koos IV VS in patients ≥ 65 years old. Further follow-up is warranted.

Hemorrhage and Recurrence of Obliterated Brain Arteriovenous Malformations Treated With Stereotactic Radiosurgery.

BACKGROUND: Although complete nidal obliteration of brain arteriovenous malformations (AVM) is generally presumed to represent durable cure, postobliteration hemorrhage, and AVM recurrence have become increasingly recognized phenomena. The goal of the study was to define hemorrhage and nidal recurrence risks of obliterated AVMs treated with stereotactic radiosurgery (SRS). METHODS: This is a retrospective cohort study from the International Radiosurgery Research Foundation comprising AVM patients treated between 1987 and 2020. Patients with AVM obliteration on digital subtraction angiography (DSA) were included. Outcomes were (1) hemorrhage and (2) AVM recurrence. Follow-up duration began at the time of AVM obliteration and was censored at subsequent hemorrhage, AVM recurrence, additional AVM treatment, or loss to follow-up. Annualized risk and survival analyses were performed. A sensitivity analysis comprising patients with AVM obliteration on magnetic resonance imaging or DSA was also performed for postobliteration hemorrhage. RESULTS: The study cohort comprised 1632 SRS-treated patients with AVM obliteration on DSA. Pediatric patients comprised 15% of the cohort, and 42% of AVMs were previously ruptured. The mean imaging follow-up after AVM obliteration was 22 months. Among 1607 patients with DSA-confirmed AVM obliteration, 16 hemorrhages (1.0%) occurred over 2223 patient-years of follow-up (0.72%/y). Of the 1543 patients with DSA-confirmed AVM obliteration, 5 AVM recurrences (0.32%) occurred over 2071 patient-years of follow-up (0.24%/y). Of the 16 patients with postobliteration hemorrhage, AVM recurrence was identified in 2 (12.5%). In the sensitivity analysis comprising 1939 patients with post-SRS AVM obliteration on magnetic resonance imaging or DSA, 16 hemorrhages (0.83%) occurred over 2560 patient-years of follow-up (0.63%/y). CONCLUSIONS: Intracranial hemorrhage and recurrent arteriovenous shunting after complete nidal obliteration are rare in AVM patients treated with SRS, and each phenomenon harbors an annual risk of <1%. Although routine postobliteration DSA cannot be recommended to SRS-treated AVM patients, long-term neuroimaging may be advisable in these patients.

Radiation necrosis in renal cell carcinoma brain metastases treated with checkpoint inhibitors and radiosurgery: An international multicenter study.

BACKGROUND: Patients with renal cell carcinoma (RCC) brain metastases are frequently treated with immune checkpoint inhibitors (ICIs) and stereotactic radiosurgery (SRS). However, data reporting on the risk of developing radiation necrosis (RN) are limited. METHODS: RN rates were compared for concurrent therapy (ICI/SRS administration within 4 weeks of one another) and nonconcurrent therapy with the χ2 test. Univariable logistic regression was used to identify factors associated with developing RN. RESULTS: Fifty patients (23 concurrent and 27 nonconcurrent) with 395 brain metastases were analyzed. The median follow-up was 12.1 months; the median age was 65 years. The median margin dose was 20 Gy, and 4% underwent prior whole-brain radiation therapy (WBRT). The median treated tumor volume was 3.32 cm3 (range, 0.06-42.38 cm3 ); the median volume of normal brain tissue receiving a dose of 12 Gy or higher (V12 Gy) was 8.42 cm3 (range, 0.27-111.22 cm3 ). Any-grade RN occurred in 17.4% and 22.2% in the concurrent and nonconcurrent groups, respectively (P = .67). Symptomatic RN occurred in 4.3% and 14.8% in the concurrent and nonconcurrent groups, respectively (P = .23). Increased tumor volume during SRS (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.01-1.19; P = .04) was associated with developing RN, although V12 Gy (OR, 1.03; 95% CI, 0.99-1.06; P = .06), concurrent therapy (OR, 0.74; 95% CI, 0.17-2.30; P = .76), prior WBRT, and ICI agents were not statistically significant. CONCLUSIONS: Symptomatic RN occurs in a minority of patients with RCC brain metastases treated with ICI/SRS. The majority of events were grade 1 to 3 and were managed medically. Concurrent ICI/SRS does not appear to increase this risk. Attempts to improve dose conformality (reduce V12) may be the most successful mitigation strategy in single-fraction SRS.

A consensus definition of supratotal resection for anatomically distinct primary glioblastoma: an AANS/CNS Section on Tumors survey of neurosurgical oncologists.

INTRODUCTION: Supratotal resection (SpTR) of glioblastoma may be associated with improved survival, but published results have varied in part from lack of consensus on the definition and appropriate use of SpTR. A previous small survey of neurosurgical oncologists with expertise performing SpTR found resection 1-2 cm beyond contrast enhancement was an acceptable definition and glioblastoma involving the right frontal and bilateral anterior temporal lobes were considered most amenable to SpTR. The general neurosurgical oncology community has not yet confirmed the practicality of this definition. METHODS: Seventy-six neurosurgical oncology members of the AANS/CNS Tumor Section were surveyed, representing 34.0% of the 223 members who were administered the survey. Participants were presented with 11 definitions of SpTR and rated each definition's appropriateness. Participants additionally reviewed magnetic resonance imaging for 10 anatomically distinct glioblastomas and assessed the tumor location's eloquence, perceived equipoise of enrolling patients in a randomized trial comparing gross total to SpTR, and their personal treatment plans. RESULTS: Most neurosurgeons surveyed agree that gross total plus resection of some non-contrast enhancement (n = 57, 80.3%) or resection 1-2 cm beyond contrast enhancement (n = 52, 73.2%) are appropriate definitions for SpTR. Cases were divided into three anatomically distinct groups by perceived equipoise between gross total and SpTR. The best clinical trial candidates were thought to be right anterior temporal (n = 58, 76.3%) and right frontal (n = 55, 73.3%) glioblastomas. CONCLUSION: Support exists among neurosurgical oncologists with varying familiarity performing SpTR to adopt the proposed consensus definition of SpTR of glioblastoma and to potentially investigate the utility of SpTR to treat right anterior temporal and right frontal glioblastomas in a clinical trial. A smaller proportion of general neurosurgical oncologists than SpTR experts would personally treat a left anterior temporal glioblastoma with SpTR.

Effect of distance from target on hypopituitarism after stereotactic radiosurgery for pituitary adenomas.

INTRODUCTION: Delayed hypopituitarism is the most common complication after stereotactic radiosurgery (SRS) for pituitary adenomas. The aim of this study was to investigate the relationship between the distance from the hypothalamic-pituitary axis to the treatment target and anterior pituitary function preservation after SRS. METHODS: Between 2007 and 2020, consecutive adult patients who underwent single-session SRS for non-functioning or hormone-secreting pituitary adenomas with ≥ 6 months of follow-up were included. Distance measurements between hypothalamic-pituitary axis structures and the SRS target volume were quantified on MRI. The primary outcome was anterior pituitary function preservation. Outcomes were compared using multivariable regression and area under the receiver operator characteristic curve (AUROC) analyses. RESULTS: The study cohort comprised 224 patients, who were categorized by preservation (n = 168) and no preservation (n = 56) of anterior pituitary function after SRS. The mean and median clinical follow-up durations were 53.7 (38.0) and 46.0 (17.0-75.0) months, respectively. Independent predictors of anterior pituitary function preservation were a greater distance between the center of the pituitary gland and center of the SRS target [OR 1.101 (1.000-1.213), p = 0.050], and a shorter clinical follow-up duration [OR 0.985 (0.977-0.993), p < 0.0001]. The adjusted AUROC for the distance from the center of the pituitary gland and center of the SRS target in predicting anterior pituitary function preservation was 0.595. The sensitivity, specificity, positive predictive value and negative predictive value in predicting anterior pituitary function preservation at the optimal cut-off distance of 15 mm were 30.0, 88.0, 89.9 and 26.2%, respectively. CONCLUSIONS: Greater distance between the normal pituitary gland and the SRS target is associated with anterior pituitary function preservation and increasing this distance should be a goal of adenoma resection. Larger prospective, multi-center studies are necessary to corroborate this finding and establish the effects of distance on hypopituitarism after SRS for pituitary adenomas.