Faculty Bibliography

OBJECTIVE:To evaluate outcomes following salvage microsurgery (MS) and salvage stereotactic radiosurgery (SRS) after failure of primary treatment for vestibular schwannomas (VS). STUDY DESIGN/METHODS:Retrospective chart review. SETTING/METHODS:Tertiary referral center. METHODS:Patients with more than 1 intervention for their VS were divided into 4 groups: MS followed by SRS (n = 61), MS followed by MS (n = 9), SRS followed by MS (n = 7), and SRS followed by SRS (n = 7), and outcomes were evaluated. RESULTS:A total of 77 patients were included (84 procedures). In group 1 (MS then SRS), 3% developed a decline in facial function, 3% developed trigeminal sensory loss, and 13% patients had gradual improvement of facial nerve function following SRS. Group 2 (MS then MS) had the highest rates of facial nerve deterioration, although all but 1 patient achieved a House-Brackmann score of II or III. Gross-total resection (GTR) was achieved in 56% of patients. When a different approach was used for salvage resection, GTR occurred more commonly, and facial nerve outcomes were similar. In group 3 (SRS then MS), GTR occurred in 43% of cases, and 2 of 7 patients developed worsened facial function. In group 4 (SRS then SRS), no patient developed facial weakness after reirradiation, and 1 developed a trigeminal nerve deficit. CONCLUSIONS:For MS recurrences/residuals, SRS is the mainstay of treatment and does not preclude facial function recovery. If salvage microsurgery is required, an alternate approach should be considered. For SRS failures, when MS is required, less-than GTR may be preferable, and reirradiation is a potential safe alternative.

Inhibition of mTORC1 signaling has been shown to diminish growth of meningiomas and schwannomas in preclinical studies, and clinical data suggest that everolimus, an orally administered mTORC1 inhibitor, may slow tumor progression in a subset of NF2 patients with vestibular schwannoma (VS). To assess the pharmacokinetics, pharmacodynamics and potential mechanisms of treatment resistance, we performed a pre-surgical (phase 0) clinical trial of everolimus in patients undergoing elective surgery for VS or meningiomas. Eligible patients with meningioma or VS requiring tumor resection enrolled on study received everolimus 10 mg daily for 10 days immediately prior to surgery. Everolimus blood levels were determined immediately prior to and after surgery. Tumor samples were collected intraoperatively. Ten patients completed protocol therapy. Median pre- and post-operative blood levels of everolimus were found to be in a high therapeutic range (17.4 ng/ml and 9.4 ng/ml, respectively). Median tumor tissue drug concentration determined by mass spectrometry was 24.3 pg/mg (range 9.2-169.2). We observed only partial inhibition of phospho-S6 in the treated tumors, indicating incomplete target inhibition compared to control tissues from untreated patients (p=0.025). Everolimus led to incomplete inhibition of mTORC1 and downstream signaling. These data may explain the limited anti-tumor effect of everolimus observed in clinical studies for NF2 patients and will inform the design of future pre-clinical and clinical studies targeting mTORC1 in meningiomas and schwannomas.

OBJECTIVE:Meningiomas that arise primarily within the cavernous sinus are often believed to be more indolent in their growth pattern. Despite this perceived growth pattern, disabling symptoms can arise even with small tumors. While research has been done on cavernous sinus meningiomas (CSMs) and their treatment, very little is known about their natural growth rates. With a better understanding of the growth rate of CSM, patient treatment and guidance can be can optimized and individualized. The goal of this study was to determine volumetric growth rates of untreated CSMs. METHODS:Thirty-seven patients with 166 MR images obtained between May 2004 and September 2019 were reviewed, with a range of 2-13 MR images per patient (average of 4.5 MR images per patient). These scans were obtained over an average follow-up period of 45.9 months (median 33.8, range 2.8-136.9 months). All imaging prior to any intervention was included in this analysis. Volumetric measurements were performed and assessed over time. RESULTS:The estimated volumetric growth rate was 23.3% per year (95% CI 10.2%-38.0%, p < 0.001), which is equivalent to an estimated volume doubling time (VDT) of 3.3 years (95% CI 2.1-7.1 years). There was no significant relationship between growth rate and patient age (p = 0.09) or between growth rate and patient sex (p = 0.78). The median absolute growth rate was 41% with a range of -1% to 1793%. With a definition of "growth" as an increase of greater than 20% during the observed period, 65% of tumors demonstrated growth within their observation interval. Growth rates for each tumor were calculated and tumors were segmented based on growth rate. Of 37 patients, 22% (8) demonstrated no growth (< 5% annual growth, equivalent to a VDT > 13.9 years), 32% (12) were designated as slow growth (annual growth rate 5%-20%, VDT 3.5-13.9 years), 38% (14) were found to have medium growth (annual growth rate 20%-100%, VDT 0.7-3.5 years), and 8% were considered fast growing (annual growth rate > 100%, VDT < 0.7 years). CONCLUSIONS:This study evaluated CSM volumetric growth rates. A deeper understanding of the natural history of untreated CSMs allows for better counseling and management of patients.

OBJECTIVE:In this study, the authors aimed to clarify the relationship between hearing loss and tumor volumetric growth rates in patients with untreated vestibular schwannoma (VS). METHODS:Records of 128 treatment-naive patients diagnosed with unilateral VS between 2012 and 2018 with serial audiometric assessment and MRI were reviewed. Tumor growth rates were determined from initial and final tumor volumes, with a median follow-up of 24.3 months (IQR 8.5-48.8 months). Hearing changes were based on pure tone averages, speech discrimination scores, and American Academy of Otolaryngology-Head and Neck Surgery hearing class. Primary outcomes were the loss of class A hearing and loss of serviceable hearing, estimated using the Kaplan-Meier method and with associations estimated from Cox proportional hazards models and reported as hazard ratios. RESULTS:Larger initial tumor size was associated with an increased risk of losing class A (HR 1.5 for a 1-cm3 increase; p = 0.047) and serviceable (HR 1.3; p < 0.001) hearing. Additionally, increasing volumetric tumor growth rate was associated with elevated risk of loss of class A hearing (HR 1.2 for increase of 100% per year; p = 0.031) and serviceable hearing (HR 1.2; p = 0.014). Hazard ratios increased linearly with increasing growth rates, without any evident threshold growth rate that resulted in a large, sudden increased risk of hearing loss. CONCLUSIONS:Larger initial tumor size and faster tumor growth rates were associated with an elevated risk of loss of class A and serviceable hearing.

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 < .05) and a Ki-67 index > 15% (HR = 1.66, P < .03) negatively correlated with PFS. MMs (HR = 3.21, P < .05), increased age (HR = 1.04, P = .04), and reduced KPS (HR = 0.95, P = .04) were associated with shortened OS. Adjuvant versus salvage SRS did not impact PFS/OS. A shortened interval between surgery and SRS improved PFS for AMs (HR = 0.99, P = .02) on subgroup analysis. Radiation necrosis occurred in 34 (12.5%) patients. Five-year rates of repeat surgery/radiation were 33.8% and 60.4%, respectively. CONCLUSION/CONCLUSIONS:AM/MMs remain challenging tumors to treat. Elevated proliferative indices are associated with tumor recurrence, while MMs have worse survival. SRS can control AM/MMs in the short term, but the 5-yr PFS rates are low, underscoring the need for improved treatment options for these patients.

PURPOSE/OBJECTIVE:Resting state functional magnetic resonance imaging (rsfMRI) is an emerging tool to explore the functional connectivity of different brain regions. We aimed to assess the disruption of functional connectivity of the Default Mode Network (DMN), Dorsal Attention Network(DAN) and Fronto-Parietal Network (FPN) in patients with glial tumors. METHODS:rsfMRI data acquired on 3T-MR of treatment-naive glioma patients prospectively recruited (2015-2019) and matched controls from the 1000 functional-connectomes-project were analyzed using the CONN functional toolbox. Seed-Based Connectivity Analysis (SBCA) and Independent Component Analysis (ICA, with 10 to 100 components) were performed to study reliably the three networks of interest. RESULTS:). For the FPN, increased connectivity was noted in the precuneus, posterior cingulate gyrus, and frontal cortex. No difference in the connectivity of the networks of interest was demonstrated between low- and high-grade gliomas, as well as when stratified by their IDH1-R132H (isocitrate dehydrogenase) mutation status. CONCLUSION/CONCLUSIONS:Altered functional connectivity is reliably found with SBCA and ICA in the DMN, DAN, and FPN in glioma patients, possibly explained by decreased connectivity between the cerebral hemispheres across the corpus callosum due to disruption of the connections.

Epilepsy is a heterogenous group of disorders defined by recurrent seizure activity due to abnormal synchronized activity of neurons. A growing number of epilepsy cases are believed to be caused by genetic factors and copy number variants (CNV) contribute to up to 5% of epilepsy cases. However, CNVs in epilepsy are usually large deletions or duplications involving multiple neurodevelopmental genes. In patients who underwent seizure focus resection for treatment-resistant epilepsy, whole genome DNA methylation profiling identified 3 main clusters of which one showed strong association with receptor tyrosine kinase (RTK) genes. We identified focal copy number gains involving epidermal growth factor receptor (EGFR) and PDGFRA loci. The dysplastic neurons of cases with amplifications showed marked overexpression of EGFR and PDGFRA, while glial and endothelial cells were negative. Targeted sequencing of regulatory regions and DNA methylation analysis revealed that only enhancer regions of EGFR and gene promoter of PDGFRA were amplified, while coding regions did not show copy number abnormalities or somatic mutations. Somatic focal copy number gains of noncoding regulatory represent a previously unrecognized genetic driver in epilepsy and a mechanism of abnormal activation of RTK genes. Upregulated RTKs provide a potential avenue for therapy in seizure disorders.

Background Functional MRI improves preoperative planning in patients with brain tumors, but task-correlated signal intensity changes are only 2%-3% above baseline. This makes accurate functional mapping challenging. Marchenko-Pastur principal component analysis (MP-PCA) provides a novel strategy to separate functional MRI signal from noise without requiring user input or prior data representation. Purpose To determine whether MP-PCA denoising improves activation magnitude for task-based functional MRI language mapping in patients with brain tumors. Materials and Methods In this Health Insurance Portability and Accountability Act-compliant study, MP-PCA performance was first evaluated by using simulated functional MRI data with a known ground truth. Right-handed, left-language-dominant patients with brain tumors who successfully performed verb generation, sentence completion, and finger tapping functional MRI tasks were retrospectively identified between January 2017 and August 2018. On the group level, for each task, histograms of z scores for original and MP-PCA denoised data were extracted from relevant regions and contralateral homologs were seeded by a neuroradiologist blinded to functional MRI findings. Z scores were compared with paired two-sided t tests, and distributions were compared with effect size measurements and the Kolmogorov-Smirnov test. The number of voxels with a z score greater than 3 was used to measure task sensitivity relative to task duration. Results Twenty-three patients (mean age ± standard deviation, 43 years ± 18; 13 women) were evaluated. MP-PCA denoising led to a higher median z score of task-based functional MRI voxel activation in left hemisphere cortical regions for verb generation (from 3.8 ± 1.0 to 4.5 ± 1.4; P < .001), sentence completion (from 3.7 ± 1.0 to 4.3 ± 1.4; P < .001), and finger tapping (from 6.9 ± 2.4 to 7.9 ± 2.9; P < .001). Median z scores did not improve in contralateral homolog regions for verb generation (from -2.7 ± 0.54 to -2.5 ± 0.40; P = .90), sentence completion (from -2.3 ± 0.21 to -2.4 ± 0.37; P = .39), or finger tapping (from -2.3 ± 1.20 to -2.7 ± 1.40; P = .07). Individual functional MRI task durations could be truncated by at least 40% after MP-PCA without degradation of clinically relevant correlations between functional cortex and functional MRI tasks. Conclusion Denoising with Marchenko-Pastur principal component analysis led to higher task correlations in relevant cortical regions during functional MRI language mapping in patients with brain tumors. © RSNA, 2020 Online supplemental material is available for this article.

PURPOSE/OBJECTIVE:Metastases should be considered in a patient with a cancer history and a sellar/suprasellar lesion, as this diagnosis can change the management strategy in such patients. Once the diagnosis is established, stereotactic radiosurgery (SRS) can be a safe and effective approach for these patients. METHODS:This case series describes five patients with pituitary metastases managed with GKRS at a single institution, taken from our prospective registry. All patients had SRS using the Gamma Knife Perfexion or Icon (Elekta), according to our standard institutional protocol. The optic nerves and chiasm were contoured, and the plan was adjusted to restrict dose to the optic apparatus as necessary. The tumor margin doses delivered were 11 Gy, 12 Gy, 14 Gy, 18 Gy (3 sessions of 6 Gy), and 12 Gy at the 50% isodose line. RESULTS:In this series, all sellar metastases were treated successfully with good radiographic and clinical response. The histology of the tumors included endometrial, gastrointestinal, and lung adenocarcinomas. Typically, histology is taken into consideration when choosing the treatment dose, along with size and location. In these patients, however, the dose used for the sellar metastases was chosen primarily for visual safety. This was typically lower than the dose for brain metastases in other locations. CONCLUSION/CONCLUSIONS:SRS provides an alternative treatment approach for sellar/suprasellar metastases with excellent local control, symptom improvement and maintenance of systemic therapy as desired. As such, CNS failure is rarely the proximate cause of demise in pituitary metastases provided that endocrinopathies are recognized and managed appropriately.