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Background Stereotactic radiosurgery (SRS) and resection are treatment options for patients with facial nerve schwannomas without mass effect. Objective This article evaluates outcomes of patients treated with SRS versus resection + SRS. Method We retrospectively compared 43 patients treated with SRS to 12 patients treated with resection + SRS. The primary study outcome was unfavorable combined endpoint, defined as worsening or new clinical symptoms, and/or tumor radiological progression. SRS (38.81 ± 5.3) and resection + SRS (67.14 ± 11.8) groups had similar clinical follow-ups. Results At the time of SRS, the tumor volumes of SRS (mean ± standard error; 1.83 ± 0.35 mL) and resection + SRS (2.51 ± 0.75 mL) groups were similar. SRS (12.15 ± 0.08 Gy) and resection + SRS (12.16 ± 0.14 Gy) groups received similar radiation doses. SRS group (42/43, 98%) had better local tumor control than the resection + SRS group (10/12, 83%, p = 0.04). Most of SRS (32/43, 74%) and resection + SRS (10/12, 83%) group patients reached a favorable combined endpoint following SRS (p = 0.52). Considering surgical associated side effects, only 2/10 patients of the resection + SRS group reached a favorable endpoint (p < 0.001). Patients of SRS group, who are > 34 years old (p = 0.02), have larger tumors (> 4 mL, 0.04), internal auditory canal (IAC) segment tumor involvement (p = 0.01) were more likely to reach an unfavorable endpoint. Resection + SRS group patients did not show such a difference. Conclusion While resection is still needed for larger tumors, SRS offers better clinical and radiological outcomes compared to resection followed by SRS for facial schwannomas. Younger age, smaller tumors, and non-IAC situated tumors are factors that portend a favorable outcome. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pineocytomas are grade 1 tumors arising from the pineal parenchyma. Gross total resection can potentially cure these benign lesions but can be associated with morbidity. This study was designed to provide multi-institutional data to evaluate the results of stereotactic radiosurgery (SRS) for pineocytomas., Methods: Centers participating in the International Radiosurgery Research Foundation were asked to review their database and provide data for patients who had SRS for histology confirmed grade 1 pineocytomas, for whom clinical and imaging follow-up of at least 6 months was available., Results: In total, 38 patients underwent SRS as part of the management of a pineocytoma. The median age at SRS was 39 years (range 8-76). SRS was performed as primary approach in 68%, adjuvant after partial resection 19%, and at recurrence in 13% of patients. The median margin dose was 15 Gy (range 11-25 Gy). The median treatment volume was 3.35 cc (range 0.1-17.9 cc). Local tumor control was achieved in 92% of patients, with a mean actuarial progression-free survival of 21.6 years (median not reached). At last follow-up, 82% were still controlled, 8% had local recurrence, and 10% had cerebrospinal fluid dissemination. Tumor control was significantly better when SRS was used as primary care compared with the adjuvant or recurrent setting (P = .016). Five patients (13%) died during follow-up, all from tumor progression. The actuarial mean survival duration was 24.3 years, with a 5-year survival rate of 91%, and an estimated rate of 76% at 29 years. Larger tumor volume at SRS was found to be correlated to increased risk of death (P = .045). Transient symptomatic adverse radiation effects were observed in 4 patients (11%)., Conclusion: SRS appears safe and effective for the management of pineocytomas. Long-term tumor control is achieved in most cases. SRS can be offered to selected patients as an alternative to surgical resection., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background and Objectives: Stereotactic radiosurgery (SRS) represents an effective treatment for nonfunctioning pituitary adenomas (NFPAs). However, no data have yet been published regarding results of SRS on NFPAs after multiple previous resections., Methods: Retrospective multicentric data of patients diagnosed with NFPA and who underwent multiple resections (≥2) before SRS were reviewed and analyzed. The treatment interval spanned the period of 1992 to 2022. Cox regression and Kaplan-Meier curves were used to assess predictive factors and the probability of tumor control and hypopituitarism., Results: Among the 311 patients (median age: 50.2 [IQR: 18.0] years), 226 (72.7%) had undergone ≥2 previous resections. The median margin dose was 14 Gy (IQR: 4.0 Gy), and the median tumor volume 3.6 cm3 (IQR: 4.8). Overall, the probability of tumor control after SRS was 93.3% (CI 95%: 89.9-96.9) and 86.7% (CI 95%: 81.1-92.6) at 5 and 10 years, respectively. A margin dose >14 Gy was associated with a decreased risk of tumor progression (hazard ratio = 0.33, CI 95% = 0.15-0.75, P = .008). At a last clinical follow-up of 4.1 (IQR 6.1) years, 10.1% (30/296) developed at least 1 new hormone deficiency after SRS. The cumulative probability of new hormone deficiency was 6.1% (95% CI: 3.0-9.1), 10.3% (95% CI: 5.8-14.6), and 18.9% (95% CI: 11.5-25.8) at 3, 5, and 10 years after SRS, respectively. The average latency between SRS and development of new hormone deficiencies was 3.3 years (IQR 4.1). A maximum point dose to the pituitary stalk >10 Gy was associated with a new deficiency (hazard ratio = 4.06, CI 95% = 1.57-10.5, P-value = .004)., Conclusion: For patients with NFPA with multiple previous resections, SRS offers effective local tumor control and a low risk of delayed hypopituitarism for managing these challenging adenomas. SRS should be strongly considered in patients with NFPA with 2 previous resections compared with considering a third resection., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Brainstem cerebral cavernous malformations (CCM) are clinically more aggressive compared to superficial CCMs. Due to their location, resection can be challenging, making stereotactic radiosurgery (SRS) an attractive alternative for symptomatic patient. Brainstem CCM patients (n = 170) were treated with Gamma Knife SRS at 11 radiosurgical centers. Hemorrhagic risk reduction, risk factors of post-SRS hemorrhage, and clinical outcomes were retrospectively analyzed. Most patients had a single (165/170 patients) brainstem CCMs treated; the majority of CCMs (165/181) presented with bleeding. Single-session SRS decreased the risk of repeat hemorrhage in patients with hemorrhagic brainstem CCM (HR: 0.17, p < 0.001) using recurrent multivariate analysis. The annual hemorrhage rate decreased from 14.8 per 100 CCM-years before SRS to 2.3 after treatment. Using univariate Cox-analysis, the probability of a new hemorrhages after SRS was reduced for patient older than 35 years (HR = 0.21, p = 0.002) and increased with a margin dose > 13 Gy (HR = 2.57, p = 0.044). Adverse radiation effect (ARE) occurred in 9 patients (5.3%) and was symptomatic in four (2.4%). At a median follow-up of 3.4 years (Inter-quartile range: 5.4), 13 patients (8.0%) had a worsened clinical status, with the treated CCM being the cause in 5.6% (10) of the patients. Single-session SRS decreased the risk of repeat hemorrhage in patients with hemorrhagic brainstem CCM and conveyed this benefit with a low risk of advrse radiation effects (ARE) and worsening clinical status., (© 2024. The Author(s).)

Background and Objectives: Stereotactic radiosurgery (SRS) with neoadjuvant embolization is a treatment strategy for brain arteriovenous malformations (AVMs), especially for those with large nidal volume or concomitant aneurysms. The aim of this study was to assess the effects of pre-SRS embolization in AVMs with an associated intracranial aneurysm (IA)., Methods: The International Radiosurgery Research Foundation AVM database from 1987 to 2018 was retrospectively reviewed. SRS-treated AVMs with IAs were included. Patients were categorized into those treated with upfront embolization (E + SRS) vs stand-alone SRS (SRS). Primary end point was a favorable outcome (AVM obliteration + no permanent radiation-induced changes or post-SRS hemorrhage). Secondary outcomes included AVM obliteration, mortality, follow-up modified Rankin Scale, post-SRS hemorrhage, and radiation-induced changes., Results: Forty four AVM patients with associated IAs were included, of which 23 (52.3%) underwent pre-SRS embolization and 21 (47.7%) SRS only. Significant differences between the E + SRS vs SRS groups were found for AVM maximum diameter (1.5 ± 0.5 vs 1.1 ± 0.4 cm3, P = .019) and SRS treatment volume (9.3 ± 8.3 vs 4.3 ± 3.3 cm3, P = .025). A favorable outcome was achieved in 45.4% of patients in the E + SRS group and 38.1% in the SRS group (P = .625). Obliteration rates were comparable (56.5% for E + SRS vs 47.6% for SRS, P = .555), whereas a higher mortality rate was found in the SRS group (19.1% vs 0%, P = .048). After adjusting for AVM maximum diameter, SRS treatment volume, and maximum radiation dose, the likelihood of achieving favorable outcome and AVM obliteration did not differ between groups (P = .475 and P = .820, respectively)., Conclusion: The likelihood of a favorable outcome and AVM obliteration after SRS with neoadjuvant embolization in AVMs with concomitant IA seems to be comparable with stand-alone SRS, even after adjusting for AVM volume and SRS maximum dose. However, the increased mortality among the stand-alone SRS group and relatively low risk of embolization-related complications suggest that these patients may benefit from a combined treatment approach., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background: Higher risk of secondary brain tumor, carotid stenosis and stroke has been reported after conventional sella irradiation for pituitary neuroendocrine tumors (PitNET). Stereotactic radiosurgery (SRS), which is a more focused approach, is now increasingly used instead. The aim was to assess the risk of secondary brain tumor, carotid stenosis/occlusion and stroke after SRS., Methods: In this multicentric retrospective study, 2,254 patients with PitNET were studied, 1,377 in the exposed group and 877 in the control group., Results: There were 9,840.1 patient-years at risk for the SRS and 5,266.5 for the control group. The 15-year cumulative probability of secondary intracranial tumor was 2.3% (95%CI:0.5%, 4.1%) for SRS and 3.7% (95%CI:0%, 8.7%) for the control group (p=0.6), with an incidence rate of 1.32 per 1,000 and 0.95 per 1,000, respectively. SRS was not associated with increased risk of tumorigenesis when stratified by age (HR: 1.59 [95%CI: 0.57, 4.47], p=0.38). The 15-year probability of new carotid stenosis/occlusion was 0.9% (95%CI: 0.2, 1.6) in the SRS and 2% (95%CI: 0, 4.4) in the control group (p=0.8). The 15-year probability of stroke was 2.6% (95%CI: 0.6%, 4.6%) in the SRS and 11.1% (95%CI: 6%, 15.9%) in the control group (p<0.001). In cox multivariate analysis stratified by age, SRS (HR 1.85[95%CI:0.64, 5.35], p=0.26) was not associated with risk of new stroke., Conclusion: No increased risk of long-term secondary brain tumor, new stenosis or occlusion and stroke was demonstrated in SRS group compared to control in this study with imaging surveillance., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background and Objectives: Pleomorphic xanthoastrocytoma (PXA) is a rare low-grade glial tumor primarily affecting young individuals. Surgery is the primary treatment option; however, managing residual/recurrent tumors remains uncertain. This international multi-institutional study retrospectively assessed the use of stereotactic radiosurgery (SRS) for PXA., Methods: A total of 36 PXA patients (53 tumors) treated at 11 institutions between 1996 and 2023 were analyzed. Data included demographics, clinical variables, SRS parameters, tumor control, and clinical outcomes. Kaplan-Meier estimates summarized the local control (LC), progression-free survival, and overall survival (OS). Secondary end points addressed adverse radiation effects and the risk of malignant transformation. Cox regression analysis was used., Results: A total of 38 tumors were grade 2, and 15 tumors were grade 3. Nine patients underwent initial gross total resection, and 10 received adjuvant therapy. The main reason for SRS was residual tumors (41.5%). The median follow-up was 34 months (range, 2-324 months). LC was achieved in 77.4% of tumors, with 6-month, 1-year, and 2-year LC estimates at 86.7%, 82.3%, and 77.8%, respectively. Younger age at SRS (hazard ratios [HR] 3.164), absence of peritumoral edema (HR 4.685), and higher marginal dose (HR 6.190) were significantly associated with better LC. OS estimates at 1, 2, and 5 years were 86%, 74%, and 49.3%, respectively, with a median OS of 44 months. Four patients died due to disease progression. Radiological adverse radiation effects included edema (n = 8) and hemorrhagic change (n = 1). One grade 3 PXA transformed into glioblastoma 13 months after SRS., Conclusion: SRS offers promising outcomes for PXA management, providing effective LC, reasonable progression-free survival, and minimal adverse events., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background: Cerebral cavernous malformations (CCMs) frequently manifest with haemorrhages. Stereotactic radiosurgery (SRS) has been employed for CCM not suitable for resection. Its effect on reducing haemorrhage risk is still controversial. The aim of this study was to expand on the safety and efficacy of SRS for haemorrhagic CCM., Methods: This retrospective multicentric study included CCM with at least one haemorrhage treated with single-session SRS. The annual haemorrhagic rate (AHR) was calculated before and after SRS. Recurrent event analysis and Cox regression were used to evaluate factors associated with haemorrhage. Adverse radiation effects (AREs) and occurrence of new neurological deficits were recorded., Results: The study included 381 patients (median age: 37.5 years (Q1-Q3: 25.8-51.9) with 414 CCMs. The AHR from diagnosis to SRS excluding the first haemorrhage was 11.08 per 100 CCM-years and was reduced to 2.7 per 100 CCM-years after treatment. In recurrent event analysis, SRS, HR 0.27 (95% CI 0.17 to 0.44), p<0.0001 was associated with a decreased risk of haemorrhage, and the presence of developmental venous anomaly (DVA) with an increased risk, HR 1.60 (95% CI 1.07 to 2.40), p=0.022. The cumulative risk of first haemorrhage after SRS was 9.4% (95% CI 6% to 12.6%) at 5 years and 15.6% (95% CI% 9 to 21.8%) at 10 years. Margin doses> 13 Gy, HR 2.27 (95% CI 1.20 to 4.32), p=0.012 and the presence of DVA, HR 2.08 (95% CI 1.00 to 4.31), p=0.049 were factors associated with higher probability of post-SRS haemorrhage. Post-SRS haemorrhage was symptomatic in 22 out of 381 (5.8%) patients, presenting with transient (15/381) or permanent (7/381) neurological deficit. ARE occurred in 11.1% (46/414) CCM and was responsible for transient neurological deficit in 3.9% (15/381) of the patients and permanent deficit in 1.1% (4/381) of the patients. Margin doses >13 Gy and CCM volume >0.7 cc were associated with increased risk of ARE., Conclusion: Single-session SRS for haemorrhagic CCM is associated with a decrease in haemorrhage rate. Margin doses ≤13 Gy seem advisable., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Objectives: Intratumoral hemorrhage (ITH) in vestibular schwannoma (VS) after stereotactic radiosurgery (SRS) is exceedingly rare. The aim of this study was to define its incidence and describe its management and outcomes in this subset of patients., Methods: A retrospective multi-institutional study was conducted, screening 9565 patients with VS managed with SRS at 10 centers affiliated with the International Radiosurgery Research Foundation., Results: A total of 25 patients developed ITH (cumulative incidence of 0.26%) after SRS management, with a median ITH size of 1.2 cm 3 . Most of the patients had Koos grade II-IV VS, and the median age was 62 years. After ITH development, 21 patients were observed, 2 had urgent surgical intervention, and 2 were initially observed and had late resection because of delayed hemorrhagic expansion and/or clinical deterioration. The histopathology of the resected tumors showed typical, benign VS histology without sclerosis, along with chronic inflammatory cells and multiple fragments of hemorrhage. At the last follow-up, 17 patients improved and 8 remained clinically stable., Conclusion: ITH after SRS for VS is extremely rare but has various clinical manifestations and severity. The management paradigm should be individualized based on patient-specific factors, rapidity of clinical and/or radiographic progression, ITH expansion, and overall patient condition., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background and Objectives: An international, multicenter, retrospective study was conducted to evaluate the long-term clinical outcomes and tumor control rates after stereotactic radiosurgery (SRS) for trigeminal schwannoma., Methods: Patient data (N = 309) were collected from 14 international radiosurgery centers. The median patient age was 50 years (range 11-87 years). Sixty patients (19%) had prior resections. Abnormal facial sensation was the commonest complaint (49%). The anatomic locations were root (N = 40), ganglion (N = 141), or dumbbell type (N = 128). The median tumor volume was 4 cc (range, 0.2-30.1 cc), and median margin dose was 13 Gy (range, 10-20 Gy). Factors associated with tumor control, symptom improvement, and adverse radiation events were assessed., Results: The median and mean time to last follow-up was 49 and 65 months (range 6-242 months). Greater than 5-year follow-up was available for 139 patients (45%), and 50 patients (16%) had longer than 10-year follow-up. The overall tumor control rate was 94.5%. Tumors regressed in 146 patients (47.2%), remained unchanged in 128 patients (41.4%), and stabilized after initial expansion in 20 patients (6.5%). Progression-free survival rates at 3 years, 5 years, and 10 years were 91%, 86%, and 80 %. Smaller tumor volume (less than 8 cc) was associated with significantly better progression-free survival ( P = .02). Seventeen patients with sustained growth underwent further intervention at a median of 27 months (3-144 months). Symptom improvement was noted in 140 patients (45%) at a median of 7 months. In multivariate analysis primary, SRS ( P = .003) and smaller tumor volume ( P = .01) were associated with better symptom improvement. Adverse radiation events were documented in 29 patients (9%)., Conclusion: SRS was associated with long-term freedom (10 year) from additional management in 80% of patients. SRS proved to be a valuable salvage option after resection. When used as a primary management for smaller volume tumors, both clinical improvement and prevention of new deficits were optimized., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)