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Introduction Historical reservations regarding radiosurgery (SRS) for small-cell-lung-cancer (SCLC) brain metastases (BrM) include concerns for short-interval/diffuse CNS-progression, poor prognoses, and increased neurological mortality specific to SCLC histology. We compared SRS outcomes for SCLC and non-small-cell-lung-cancer (NSCLC) where SRS is well established. Methods Multicenter first-line SRS outcomes for SCLC and NSCLC from 2000-2022 were retrospectively collected (N=892-SCLC/N=4,785-NSCLC). Data from the prospective JLGK0901 SRS trial were analyzed as a comparison cohort (N=98-SCLC/N=794-NSCLC). OS and CNS-progression were analyzed using Cox-Proportional-Hazard and Fine-Gray models, respectively, with multivariable (MV) adjustment (including age/sex/performance-status/year/extracranial disease/BrM-number/BrM-volume). Mutation-stratified analyses were performed in propensity score-matched (PSM) retrospective cohorts of EGFR/ALK-positive-NSCLC, mutation-negative-NSCLC, and SCLC. Results OS was superior with NSCLC over SCLC in the retrospective dataset (median-OS, 10.5 vs 8.6 months, MV-p Conclusion After SRS, SCLC was associated with shorter OS compared to NSCLC. CNS progression occurred earlier in SCLC overall but was similar in patients matched on baseline characteristics. Neurological mortality, lesions at CNS-progression, and leptomeningeal-progression were comparable. These findings may better inform clinical decision-making for SCLC patients.

OBJECTIVE 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. METHODS 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. RESULTS 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. CONCLUSIONS SRS offers effective tumor control of hormone-producing pituitary adenomas in the majority of patients but a lower rate of endocrine improvement or remission.

Objective: the optimal management of asymptomatic, skull-based meningiomas is not well defined. The aim of this study is to compare the imaging and clinical outcomes of patients with asymptomatic, skull-based meningiomas managed either with upfront stereotactic radiosurgery (SRS) or active surveillance. Methods: this retrospective, multicenter study involved patients with asymptomatic, skull-based meningiomas. The study end-points included local tumor control and the development of new neurological deficits attributable to the tumor. Factors associated with tumor progression and neurological morbidity were also analyzed. Results: the combined unmatched cohort included 417 patients. Following propensity score matching for age, tumor volume, and follow-up 110 patients remained in each cohort. Tumor control was achieved in 98.2% and 61.8% of the SRS and active surveillance cohorts, respectively. SRS was associated with superior local tumor control (p < 0.001, HR = 0.01, 95% CI = 0.002-0.13) compared to active surveillance. Three patients (2.7%) in the SRS cohort and six (5.5%) in the active surveillance cohort exhibited neurological deterioration. One (0.9%) patient in the SRS-treated and 11 (10%) patients in the active surveillance cohort required surgical management of their meningioma during follow-up. Conclusions: SRS is associated with superior local control of asymptomatic, skull-based meningiomas as compared to active surveillance and does so with low morbidity rates. SRS should be offered as an alternative to active surveillance as the initial management of asymptomatic skull base meningiomas. Active surveillance policies do not currently specify the optimal time to intervention when meningioma growth is noted. Our results indicate that if active surveillance is the initial management of choice, SRS should be recommended when radiologic tumor progression is noted and prior to clinical progression., NA

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 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.

OBJECTIVE Investigations of the combined effects of neoadjuvant Onyx embolization and stereotactic radiosurgery (SRS) on brain arteriovenous malformations (AVMs) have not accounted for initial angioarchitectural features prior to neuroendovascular intervention. The aim of this retrospective, multicenter matched cohort study is to compare the outcomes of SRS with versus without upfront Onyx embolization for AVMs using de novo characteristics of the preembolized nidus. METHODS The International Radiosurgery Research Foundation AVM databases from 1987 to 2018 were retrospectively reviewed. Patients were categorized based on AVM treatment approach into Onyx embolization (OE) and SRS (OE+SRS) or SRS alone (SRS-only) cohorts and then propensity score matched in a 1:1 ratio. The primary outcome was AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiological and symptomatic radiation-induced changes (RICs), and cyst formation. Comparisons were analyzed using crude rates and cumulative probabilities adjusted for competing risk of death. RESULTS The matched OE+SRS and SRS-only cohorts each comprised 53 patients. Crude rates (37.7% vs 47.2% for the OE+SRS vs SRS-only cohorts, respectively; OR 0.679, p = 0.327) and cumulative probabilities at 3, 4, 5, and 6 years (33.7%, 44.1%, 57.5%, and 65.7% for the OE+SRS cohort vs 34.8%, 45.5%, 59.0%, and 67.1% for the SRS-only cohort, respectively; subhazard ratio 0.961, p = 0.896) of AVM obliteration were similar between the matched cohorts. The secondary outcomes of the matched cohorts were also similar. Asymptomatic and symptomatic embolization-related complication rates in the matched OE+SRS cohort were 18.9% and 9.4%, respectively. CONCLUSIONS Pre-SRS AVM embolization with Onyx does not appear to negatively influence outcomes after SRS. These analyses, based on de novo nidal characteristics, thereby refute previous studies that found detrimental effects of Onyx embolization on SRS-induced AVM obliteration. However, given the risks incurred by nidal embolization using Onyx, this neoadjuvant intervention should be used judiciously in multimodal treatment strategies involving SRS for appropriately selected large-volume or angioarchitecturally high-risk AVMs.

Resection of clinoid meningiomas can be associated with significant morbidity. Experience with stereotactic radiosurgery (SRS) for clinoid meningiomas remains limited. We studied the safety and effectiveness of SRS for clinoid meningiomas. From twelve institutions participating in the International Radiosurgery Research Foundation, we pooled patients treated with SRS for radiologically suspected or histologically confirmed WHO grade I clinoid meningiomas. Two hundred seven patients (median age: 56 years) underwent SRS for clinoid meningiomas. Median treatment volume was 8.02 cm3, and 87% of tumors were immediately adjacent to the optic apparatus. The median tumor prescription dose was 12 Gy, and the median maximal dose to the anterior optic apparatus was 8.5 Gy. During a median post-SRS imaging follow-up of 51.1 months, 7% of patients experienced tumor progression. Greater margin SRS dose (HR = 0.700, p = 0.007) and pre-SRS radiotherapy (HR = 0.004, p

BACKGROUND Stereotactic radiosurgery (SRS) is increasingly considered for selected olfactory groove meningiomas (OGMs). OBJECTIVE To investigate the safety and efficacy of SRS for OGMs. METHODS From 20 institutions participating in the International Radiosurgery Research Foundation, we pooled patients who underwent SRS for histologically confirmed or radiologically suspected WHO grade I OGMs and were followed for 6 mo or more after the SRS. RESULTS In total, 278 (median age 57 yr) patients underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) WHO grade I OGMs Median treatment volume was 4.60 cm3 (range: 0.12-27.3 cm3), median prescription dose was 12 Gy, and median dose to the olfactory nerve was 11.20 Gy. During median post-SRS imaging follow-up of 39 mo (range: 6-240 mo), 43% of patients had partial or marginal response, 54% of patients had stable disease, and 3% of patients experienced progression. During median post-SRS clinical follow-up of 51 mo (range: 6-240 mo), 36 (13%) patients experienced clinical and/or radiological adverse radiation events (AREs). Elevated risk of AREs was associated with larger OGM volume (P = .009) and pre-SRS peritumoral T2/fluid-attenuated inversion-recovery signal abnormalities (P

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.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.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.SRS can be a safe alternative to surgery for selected Koos IV VS in patients ≥ 65 years old. Further follow-up is warranted.

Purpose Surgery is the treatment of choice for large vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has been suggested as an alternative to resection in selected patients. However, the safety and efficacy of SRS in Koos grade IV patients ≤45 years old has not been evaluated. The aim of this study is to describe the clinical and radiological outcomes of Koos grade IV in young patient managed with a single-session SRS. Methods This retrospective, multicenter analysis included SRS-treated patients, ≤45 years old presenting with non-life threatening or incapacitating symptoms due to a Koos Grade IV VS and with follow-up ≥ 12 months. Tumor control and neurological outcomes were evaluated. Results 176 patients (median age of 36.0 (IQR 9) and median tumor volume of 9.3 cm3 (IQR 4.7)) were included. The median prescription dose was 12 Gy (IQR 0.5). Median follow-up period was 37.5 (IQR 53.5) months. The 5- and 10-year progression-free survival was 90.9 and 86.7%. Early tumor enlargement occurred in 10.9% of cases and was associated with tumor progression at the last follow-up. The probability of serviceable hearing preservation at 5- and 10-years was 56.8% and 45.2%, respectively. The probability of improvement or preservation of facial nerve function was 95.7% at 5 and 10-years. Adverse radiation effects were noted in 19.9%. New-onset hydrocephalus occurred in 4.0%. Conclusion Single-session SRS is a safe and effective alternative to surgical resection in selected patients ≤45 years old particularly those with medical co-morbidities and those who decline resection. Longer term follow up is warranted.

BACKGROUND Pediatric brain arteriovenous malformations (AVMs) are a significant cause of morbidity but the role of multimodal therapy in the treatment of these lesions is not well understood. OBJECTIVE To compare the outcomes of stereotactic radiosurgery (SRS) with and without prior embolization for pediatric AVMs. METHODS We retrospectively evaluated the International Radiosurgery Research Foundation pediatric AVM database. AVMs were categorized, based on use of pre-embolization (E + SRS) or lack thereof (SRS-only). Outcomes were compared in unadjusted and inverse probability weight (IPW)-adjusted models. Favorable outcome was defined as obliteration without post-SRS hemorrhage or permanent radiation-induced changes (RIC). RESULTS The E + SRS and SRS-only cohorts comprised 91 and 448 patients, respectively. In unadjusted models, the SRS-only cohort had higher rates of obliteration (68.5% vs 43.3%

Background The optimal management of patients with incidental meningiomas remains unclear. The aim of this study was to characterize the radiologic and neurological outcomes of expectant and stereotactic radiosurgery (SRS) management of asymptomatic meningioma patients. Methods Using data from 14 centers across 10 countries, the study compares SRS outcomes to active surveillance of asymptomatic meningiomas. Local tumor control of asymptomatic meningiomas and development of new neurological deficits attributable to the tumor were evaluated in the SRS and conservatively managed groups. Results In the unmatched cohorts, 727 meningioma patients underwent SRS and were followed for a mean of 57.2 months. In the conservatively managed cohort, 388 patients were followed for a mean of 43.5 months. Tumor control was 99.0% of SRS and 64.2% of conservatively managed patients (P < .001; OR 56.860 [95% CI 26.253-123.150]). New neurological deficits were 2.5% in the SRS and 2.8% of conservatively managed patients (P = .764; OR 0.890 [95% CI 0.416-1.904]). After 1:1 propensity matching for patient age, tumor volume, location, and imaging follow-up, tumor control in the SRS and conservatively managed cohorts was 99.4% and 62.1%, respectively (P < .001; OR 94.461 [95% CI 23.082-386.568]). In matched cohorts, new neurological deficits were noted in 2.3% of SRS-treated and 3.2% of conservatively managed patients (P = .475; OR 0.700 [95% CI 0.263-1.863]). Conclusions SRS affords superior radiologic tumor control compared to active surveillance without increasing the risk of neurological deficits in asymptomatic meningioma patients. While SRS and active surveillance are reasonable options, SRS appears to alter the natural history of asymptomatic meningiomas including tumor progression in the majority of patients treated.

BACKGROUND: Stereotactic radiosurgery (SRS) is increasingly used for management of perioptic meningiomas. OBJECTIVE: To study the safety and effectiveness of SRS for perioptic meningiomas. METHODS: From 12 institutions participating in the International Radiosurgery Research Foundation (IRRF), we retrospectively assessed treatment parameters and outcomes following SRS for meningiomas located within 3 mm of the optic apparatus. RESULTS: A total of 438 patients (median age 51 yr) underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) perioptic meningiomas. Median treatment volume was 8.01 cm(3). Median prescription dose was 12 Gy, and median dose to the optic apparatus was 8.50 Gy. A total of 405 patients (93%) underwent single-fraction SRS and 33 patients (7%) underwent hypofractionated SRS. During median imaging follow-up of 55.6 mo (range: 3.15-239 mo), 33 (8%) patients experienced tumor progression. Actuarial 5-yr and 10-yr progression-free survival was 96% and 89%, respectively. Prescription dose of ≥12 Gy (HR: 0.310; 95% CI [0.141-0.679], P = .003) and single-fraction SRS (HR: 0.078; 95% CI [0.016-0.395], P = .002) were associated with improved tumor control. A total of 31 (10%) patients experienced visual decline, with actuarial 5-yr and 10-yr post-SRS visual decline rates of 9% and 21%, respectively. Maximum dose to the optic apparatus ≥10 Gy (HR = 2.370; 95% CI [1.086-5.172], P = .03) and tumor progression (HR = 4.340; 95% CI [2.070-9.097], P

BACKGROUND Atypical and anaplastic meningiomas have reduced progression-free/overall survival (PFS/OS) compared to benign meningiomas. Stereotactic radiosurgery (SRS) for atypical meningiomas (AMs) and anaplastic meningiomas (malignant meningiomas, MMs) has not been adequately described. OBJECTIVE To define clinical/radiographic outcomes for patients undergoing SRS for AM/MMs. METHODS An international, multicenter, retrospective cohort study was performed to define clinical/imaging outcomes for patients receiving SRS for AM/MMs. Tumor progression was assessed with response assessment in neuro-oncology (RANO) criteria. Factors associated with PFS/OS were assessed using Kaplan-Meier analysis and a Cox proportional hazards model. RESULTS A total of 271 patients received SRS for AMs (n = 233, 85.9%) or MMs (n = 38, 14.0%). Single-fraction SRS was most commonly employed (n = 264, 97.4%) with a mean target dose of 14.8 Gy. SRS was used as adjuvant treatment (n = 85, 31.4%), salvage therapy (n = 182, 67.2%), or primary therapy (1.5%). The 5-yr PFS/OS rate was 33.6% and 77.0%, respectively. Increasing age (hazard ratio (HR) = 1.01, P 15% (HR = 1.66, P

Background Choroid plexus tumors (CPT) are rare epithelial tumors of the choroid plexus. Gross total resection (GTR) may be curative, but it is not always possible. Objective To evaluate the role of Gamma Knife stereotactic radiosurgery (GKSRS) as either a primary or adjuvant management option for WHO grade I-III CPT through a multicenter project. Methods A total of 32 patients (20 females) with a total of 43 treated tumors were included in the analysis. A total of 25 patients (78%) had undergone initial surgical resection. The median total tumor volume was 2.2 cc, and the median margin and maximum doses were 13 and 25.5 Gy, respectively. Results Local tumor control was achieved in 69% of cases. Local tumor progression-free survival (PFS) rate for low-grade tumors at 1, 3, and 5 yr was 90%, 77%, 58%, respectively. The actuarial local tumor PFS rate for high-grade tumors at 1, 3, and 5 yr was 77%, 62%, and 62%, respectively. There was no significant difference in local tumor control rates between low- and high-grade CPT (P = .3). Gender, age, and degree of resection were not associated with treated tumor PFS. Distant intracranial spread developed in 6 patients at a median of 22 mo after initial SRS. Actuarial distant brain tumor PFS rate at 1, 2, 5, and 10 yr was 93%, 88%, 78%, and 65%, respectively. Three patients (9%) developed persistent symptomatic adverse radiation effects at a median of 11 mo after the procedure. Conclusion GKSRS represents a minimally invasive alternative management strategy for imaging defined or surgically recurrent low- and high-grade CPT.

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As our digital footprints are collected and analysed by the media and fed back at us as new experiences, providing more data to collect, data circulates in a loop from audiences to media and back. This data loop is for media studies an occasion to revisit the media–audience nexus in an age of datafication. We argue that an audience perspective is needed in order to break with the structure–agency linearity in current understanding of datafication. In this article, we develop a model of the data loop that first presents the fundamentals of data circulation between social actors and digital interfaces, then the moments of agency between actors in a relation of mutual dependence. The article closes with a discussion of previous models within media and communication that have addressed similar ideas, such as audience feedback, mutuality and circularity.

Background Embolization of brain arteriovenous malformations (AVMs) using ethylene-vinyl alcohol copolymer (Onyx) embolization may influence the treatment effects of stereotactic radiosurgery (SRS) differently than other embolysates. Objective To compare the outcomes of pre-SRS AVM embolization with vs without Onyx through a multicenter, retrospective matched cohort study. Methods We retrospectively reviewed International Radiosurgery Research Foundation AVM databases from 1987 to 2018. Embolized AVMs treated with SRS were selected and categorized based on embolysate usage into Onyx embolization (OE + SRS) or non-Onyx embolization (NOE + SRS) cohorts. The 2 cohorts were matched in a 1:1 ratio using de novo AVM features for comparative analysis of outcomes. Results The matched cohorts each comprised 45 patients. Crude AVM obliteration rates were similar between the matched OE + SRS vs NOE + SRS cohorts (47% vs 51%; odds ratio [OR] = 0.837, P = .673). Cumulative probabilities of obliteration were also similar between the OE + SRS vs NOE + SRS cohorts (subhazard ratio = 0.992, P = .980). Rates of post-SRS hemorrhage, all-cause mortality, radiation-induced changes, cyst formation, and embolization-associated complications were similar between the matched cohorts. Sensitivity analysis for AVMs in the OE + SRS cohort embolized with Onyx alone revealed a higher rate of asymptomatic embolization-associated complications in this subgroup compared to the NOE + SRS cohort (36% vs 15%; OR = 3.297, P = .034), but the symptomatic complication rates were similar. Conclusion Nidal embolization using Onyx does not appear to differentially impact the outcomes of AVM SRS compared with non-Onyx embolysates. The embolic agent selected for pre-SRS AVM embolization should reflect both the experience of the neurointerventionalist and target of endovascular intervention.

OBJECTIVEContrary to the better described obliteration- and hemorrhage-related data after stereotactic radiosurgery (SRS) of brain arteriovenous malformations (AVMs) in pediatric patients, estimates of the rarer complications, including cyst and tumor formation, are limited in the literature. The aim of the present study was to assess the long-term outcomes and risks of SRS for AVMs in pediatric patients (age < 18 years).METHODSThe authors retrospectively analyzed the International Radiosurgery Research Foundation pediatric AVM database for the years 1987 to 2018. AVM obliteration, post-SRS hemorrhage, cyst formation, and tumor formation were assessed. Cumulative probabilities, adjusted for the competing risk of death, were calculated.RESULTSThe study cohort comprised 539 pediatric AVM patients (mean follow-up 85.8 months). AVM obliteration was observed in 64.3% of patients, with cumulative probabilities of 63.6% (95% CI 58.8%–68.0%), 77.1% (95% CI 72.1%–81.3%), and 88.1% (95% CI 82.5%–92.0%) over 5, 10, and 15 years, respectively. Post-SRS hemorrhage was observed in 8.4% of patients, with cumulative probabilities of 4.9% (95% CI 3.1%–7.2%), 9.7% (95% CI 6.4%–13.7%), and 14.5% (95% CI 9.5%–20.5%) over 5, 10, and 15 years, respectively. Cyst formation was observed in 2.1% of patients, with cumulative probabilities of 5.5% (95% CI 2.3%–10.7%) and 6.9% (95% CI 3.1%–12.9%) over 10 and 15 years, respectively. Meningiomas were observed in 2 patients (0.4%) at 10 and 12 years after SRS, with a cumulative probability of 3.1% (95% CI 0.6%–9.7%) over 15 years.CONCLUSIONSAVM obliteration can be expected after SRS in the majority of the pediatric population, with a relatively low risk of hemorrhage during the latency period. Cyst and benign tumor formation after SRS can be observed in 7% and 3% of patients over 15 years, respectively. Longitudinal surveillance for delayed neoplasia is prudent despite its low incidence.

OBJECTIVEThe role of primary stereotactic radiosurgery (SRS) in patients with medically refractory acromegaly who are not operative candidates or who refuse resection is poorly understood. The aim of this multicenter, matched cohort study was to compare the outcomes of primary versus postoperative SRS for acromegaly.METHODSThe authors reviewed an International Radiosurgery Research Foundation database of 398 patients with acromegaly who underwent SRS and categorized them into primary or postoperative cohorts. Patients in the primary SRS cohort were matched, in a 1:2 ratio, to those in the postoperative SRS cohort, and the outcomes of the 2 matched cohorts were compared.RESULTSThe study cohort comprised 78 patients (median follow-up 66.4 months), including 26 and 52 in the matched primary and postoperative SRS cohorts, respectively. In the primary SRS cohort, the actuarial endocrine remission rates at 2 and 5 years were 20% and 42%, respectively. The Cox proportional hazards model showed that a lower pre-SRS insulin-like growth factor–1 level was predictive of initial endocrine remission (p = 0.03), whereas a lower SRS margin dose was predictive of biochemical recurrence after initial remission (p = 0.01). There were no differences in the rates of radiological tumor control (p = 0.34), initial endocrine remission (p = 0.23), biochemical recurrence after initial remission (p = 0.33), recurrence-free survival (p = 0.32), or hypopituitarism (p = 0.67) between the 2 matched cohorts.CONCLUSIONSPrimary SRS has a reasonable benefit-to-risk profile for patients with acromegaly in whom resection is not possible, and it has similar outcomes to endocrinologically comparable patients who undergo postoperative SRS. SRS with medical therapy in the latent period can be used as an alternative to surgery in selected patients who cannot or do not wish to undergo resection.

OBJECTIVECentral neurocytomas (CNs) are uncommon intraventricular tumors, and their rarity renders the risk-to-benefit profile of stereotactic radiosurgery (SRS) unknown. The aim of this multicenter, retrospective cohort study was to evaluate the outcomes of SRS for CNs and identify predictive factors.METHODSThe authors retrospectively analyzed a cohort of patients with CNs treated with SRS at 10 centers between 1994 and 2018. Tumor recurrences were classified as local or distant. Adverse radiation effects (AREs) and the need for a CSF shunt were also evaluated.RESULTSThe study cohort comprised 60 patients (median age 30 years), 92% of whom had undergone prior resection or biopsy and 8% received their diagnosis based on imaging alone. The median tumor volume and margin dose were 5.9 cm3 and 13 Gy, respectively. After a median clinical follow-up of 61 months, post-SRS tumor recurrence occurred in 8 patients (13%). The 5- and 10-year local tumor control rates were 93% and 87%, respectively. The 5- and 10-year progression-free survival rates were 89% and 80%, respectively. AREs were observed in 4 patients (7%), but only 1 was symptomatic (2%). Two patients underwent post-SRS tumor resection (3%). Prior radiotherapy was a predictor of distant tumor recurrence (p = 0.044). Larger tumor volume was associated with pre-SRS shunt surgery (p = 0.022).CONCLUSIONSTreatment of appropriately selected CNs with SRS achieves good tumor control rates with a reasonable complication profile. Distant tumor recurrence and dissemination were observed in a small proportion of patients, which underscores the importance of close post-SRS surveillance of CN patients. Patients with larger CNs are more likely to require shunt surgery before SRS.

Meningioma, a type of brain tumor, is a common incidental finding on brain imaging. The best management approach for patients with an incidental meningioma remains unclear. This retrospective multi-center study investigated the outcomes of patients with an incidental meningioma in a frontobasal location, who were managed with active surveillance (n = 28) compared to stereotactic radiosurgery (SRS) (n = 84). Within 5 years of follow-up, SRS improved the radiological control of incidental frontobasal meningiomas (0% vs. 52%), but no symptoms occurred in either group. In the active surveillance cohort, 12% underwent an intervention for tumor growth. The findings of this study provide information to enable shared decision making between clinicians and patients with incidental frontobasal meningiomas. Meningioma is a common incidental finding, and clinical course varies based on anatomical location. The aim of this sub-analysis of the IMPASSE study was to compare the outcomes of patients with an incidental frontobasal meningioma who underwent active surveillance to those who underwent upfront stereotactic radiosurgery (SRS). Data were retrospectively collected from 14 centres. The active surveillance (n = 28) and SRS (n = 84) cohorts were compared unmatched and matched for age, sex, and duration of follow-up (n = 25 each). The study endpoints included tumor progression, new symptom development, and need for further intervention. Tumor progression occurred in 52.0% and 0% of the matched active surveillance and SRS cohorts, respectively (p < 0.001). Five patients (6.0%) treated with SRS developed treatment related symptoms compared to none in the active monitoring cohort (p = 0.329). No patients in the matched cohorts developed symptoms attributable to treatment. Three patients managed with active surveillance (10.7%, unmatched; 12.0%, matched) underwent an intervention for tumor growth with no persistent side effects after treatment. No patients subject to SRS underwent further treatment. Active monitoring and SRS confer a similarly low risk of symptom development. Upfront treatment with SRS improves imaging-defined tumor control. Active surveillance and SRS are acceptable treatment options for incidental frontobasal meningioma., NA

Brain metastases are frequently seen in neurosurgical practice. Standardised criteria are created to better classify these common pathologies in research studies. This study’s goal was to evaluate RANO-BM (Response Assessment in Neuro-Oncology - Brain Metastases) criteria’s current thresholds in a cohort of patients with brain metastases managed by stereotactic radiosurgery (SRS). We performed a retrospective metastasis-level analysis of patients treated with SRS for brain metastases. The data collected included cohort demographics, metastases characteristics, outcomes, and the rate of true positives, false negatives, true negatives and false positives as defined by RANO-BM criteria at last follow-up before second SRS. 251 metastases in 50 patients were included in the analysis. RANO-BM criteria using current thresholds yielded a sensitivity of 38%, a specificity of 95%, a positive predictive value of 71% and a negative predictive value of 84%. Modified RANO-BM criteria using absolute diameter differences of 2.5 mm yielded a sensitivity of 83%, a specificity of 87%, a positive predictive value of 67% and a negative predictive value of 94%. Pseudoprogression occurred significantly earlier than tumor progression, with a median time of onset of 6.9 months and 12.1 months respectively. Current RANO-BM criteria unreliably identifies clinically relevant tumor progression, but are useful in assessing diameter increases caused by tumor progression and pseudoprogression.

OBJECTIVE Immune checkpoint inhibitors (ICI) and stereotactic radiosurgery (SRS) are commonly utilized in the management of brain metastases. Treatment-related imaging changes (TRIC) are a frequently observed clinical manifestation and are commonly classified as radiographic radiation necrosis. However, these findings are not well characterized and may predict for response to SRS and ICI. METHODS The diagnosis-specific graded prognostic assessment was used to guide variable selection. TRIC were determined based upon MRI, PET/CT, or MR spectroscopy and a consensus by local clinical providers was required. RESULTS The analysis included 697 patients with 4,536 brain metastases across 11 institutions in 4 countries. The median follow-up after SRS was 13.6 months. The median age was 66 years, 54.1% of patients were male, and 57.3%, 36.3%, and 6.4% were non-small cell lung cancer, melanoma, and renal cell carcinoma (RCC) histology, respectively. TRIC were observed in 9.8%. On univariable analysis, Karnofsky Performance Status (KPS) (hazard ratio [HR]: 0.98; p < 0.001), presence of TRIC (HR: 0.67; p = 0.03), female sex (HR: 0.67; p < 0.001), and prior resection (HR: 0.60; p = 0.03) were associated with improved OS. On multivariable analysis, KPS (HR: 0.98; p < 0.001) and the presence of TRIC (HR: 0.66; p = 0.03) were associated with improved OS. A V12 Gy ≥ 10 cm3 (Odds Ratio [OR]: 2.78; p < 0.001), prior whole brain radiation therapy (OR: 3.46; p = 0.006), and RCC histology (OR: 3.10; p = 0.01) were associated with an increased probability of developing TRIC. The median OS in patients with and without TRIC was 29.0 and 23.1 months, respectively (log-rank p = 0.03). CONCLUSION TRIC following ICI and SRS are associated with a median OS benefit of approximately 6 months. Further prospective study is warranted to further elucidate the role and etiology of this common clinical scenario.

Background Long-term data regarding stereotactic radiosurgery (SRS) as a standalone therapy for unruptured pediatric brain arteriovenous malformations (AVMs) are incompletely defined. Objective To evaluate, in a multicenter, retrospective cohort study, the outcomes after SRS for unruptured, intervention-naive pediatric AVMs. Methods To retrospectively analyze the International Radiosurgery Research Foundation pediatric AVM database from 1987 to 2018. Pediatric patients with unruptured, previously untreated AVMs who underwent SRS were included. The primary endpoint was a composite of hemorrhagic stroke, death, or permanently symptomatic radiation-induced changes. Results The study cohort comprised 101 patients (mean follow-up 80.8 mo). The primary endpoint occurred in 14%, comprising hemorrhagic stroke, death, and permanent radiation-induced changes in 6%, 3%, and 8%, respectively. Estimated probabilities of the primary endpoint were 5.2%, 10.8%, and 23.0% at 2, 5, and 10 yr, respectively. Estimated probabilities of AVM obliteration at 5 and 10 yr were 64% and 82%, respectively. Single SRS treatment (P = .007) and higher margin dose (P = .005) were predictors of obliteration. Subgroup analysis of Spetzler-Martin grade I-III AVMs estimated primary endpoint probabilities of 3.7%, 8.4%, and 18.7% at 2, 5, and 10 yr, respectively. Conclusion Treatment of unruptured, intervention-naive AVMs in the pediatric population with SRS carries an approximately 2% annual risk of morbidity and mortality, which appears to plateau after 10 yr. The poorly described natural history of pediatric AVMs renders any comparison of SRS vs conservative management imperfect.