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71 citation(s) found for "Bauman, Megan".

RADT-11. THE HEMORRHAGIC RISK OF MELANOMA BRAIN METASTASES AFTER STEREOTACTIC RADIOSURGERY
Bouchal, Samantha, Riviere-Cazaux, Cécile , Pumford, Andrew, Brown, Paul D. , Yan, Elizabeth , Stafford, Scott L., Link, Michael J. , Pollock, Bruce E. , Hong, Sukwoo , Bauman, Megan M. J. , Markovic, Svetomir N. , Burns, Terry C. , Jusué-Torres, Ignacio , Parney, Ian F.

Mayo Clinic

Neuro-Oncology | November 11, 2023 | Volume: 25 | Issue: Supplement_5 | Pages: v50-v50

10.1093/neuonc/noad179.0200 Get It

Abstract OBJECTIVE This study aimed to analyze the hemorrhagic risk of melanoma brain metastases following SRS. METHODS A retrospective analysis was conducted using a prospective institutional database between 1990 and 2021. Lesional hemorrhage was categorized as definite or possible, and hemorrhage severity was graded using CTCAE. RESULTS The study identified 291 patients with 1083 lesions. The mean age of patients was 60 ± 15 years, with 61% being male. Median follow-up was 11 months, corresponding to 581 patient-years. Among the patients, 82 (28%) experienced 135 lesional hemorrhages (13%). Of these, 88 lesions in 61 patients were grade 1-2 hemorrhages, 42 lesions in 25 patients were grade 3, and five lesions in five patients progressed from grade 1 to 3. Surgical intervention was required for 17 lesions (2%) in 16 patients (5%). Lesional hemorrhage was associated with radiosurgery performed between 2015 and 2021 (OR, 0.373; 95% CI, 0.231-0.60; p < 0.001), increasing marginal dose (OR, 0.89; 95% CI, 0.82-0.98; p = 0.017), antiplatelet use (OR, 0.192; 95% CI, 0.082-0.45; p < 0.001), and WBRT (OR, 0.51; 95% CI, 0.330-0.77; p = 0.0017). The cumulative lesional hemorrhage risk reached 17–20% at 36 months following radiosurgery, with 95-96% of hemorrhages occurring within the initial year. Median OS was 11 months (95% CI, 9-13 months). Patients who received radiosurgery between 2015 and 2021 exhibited a median OS of 17 months (95% CI, 10-24 months; p < 0.001), while those without hemorrhage had a median OS of 12 months (95% CI, 10-14 months; p = 0.054). CONCLUSIONS Definitive hemorrhage risk was 17% for melanoma brain metastases after SRS within the first three years, with 95% of lesional hemorrhages occurring within the initial year. Surgical intervention was necessary in 5% of patients. Hemorrhage risk and overall survival improved after 2015.
BIOM-34. NON-NEOPLASTIC PLASMA EV SUBPOPULATIONS CORRELATE WITH TUMOR SIZE AND OVERALL SURVIVAL IN GLIOBLASTOMA INDEPENDENT OF STEROID USAGE
Aibaidula, Abudumijiti, Bouchal, Samantha, Bauman, Megan M. J. , Ghaith, Abdul Karim , Parney, Ian F.

Mayo Clinic

Neuro-Oncology | November 11, 2023 | Volume: 25 | Issue: Supplement_5 | Pages: v11-v12

10.1093/neuonc/noad179.0045 Get It

Abstract INTRODUCTION Extracellular Vesicles (EVs) are lipid bilayer particles present in almost all biofluids and carry tumor-specific molecular cargo. Plasma EVs are promising sources of biomarker discovery for glioblastoma (GBM). The clinical relevance of non-neoplastic plasma EVs in GBM remains unclear. In this study, we determine if associations exist between plasma EV subpopulation frequencies in GBM and clinical factors. METHODS Platelet-free plasma samples of 63 GBM, 43 Grade 2 glioma, and 45 healthy donors were included. All glioma plasma samples were collected before surgery. Plasma EV subpopulation frequency based on surface expression of EV-associated tetraspanins (CD9/CD81/CD63) and markers of cell origin (CD45/CD41a/CD11b/CD31) was determined by spectral flow cytometry. Clinical information including age, surgery, MGMT methylation status, corticosteroid usage, tumor volume, and overall survival data was recorded. RESULTS Compared to normal donors, GBM patients had increased CD9+, CD63+, CD81+, and CD11b+ EVs but decreased CD41a+ EVs. GBM patients also had the highest frequency of myeloid-derived CD9+CD11b+ EVs (20.17%) followed by grade 2 gliomas (13.78%) and normal donors (2.76%, p< 0.001). More GBM patients (29/63, 46.0%) received preoperative corticosteroids than grade 2 glioma patients (9/43, 20.9%; p = 0.008). Corticosteroid use was not associated with differences in EV subpopulation frequencies in GBM or grade 2 glioma patients. Pearson correlation analysis showed weak but statistically significant correlations between GBM total tumor volume and CD9+ EVs (p = 0.014), CD41a+ EVs (p = 0.037), and CD9+/CD63-/CD81- EVs (p = 0.007). In GBM patients, younger age (< 60 yrs, p = 0.01), gross total resection (p = 0.02), MGMT methylation (p = 0.002), high CD9+ EV expression (p = 0.011), low CD9+CD63-CD81- EV expression (p = 0.009) and low CD9+CD11b+ EV expression (p = 0.006) correlated with longer overall survival. CONCLUSION Differentially expressed non-neoplastic plasma EV subpopulations have significant clinical relevance in GBM including association with tumor volume and predicting survival. Validation of those markers in larger cohorts could reveal new prognostic biomarkers for GBM.
Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review
Carlstrom, Lucas P. , Oushy, Soliman , Perry, Avital , Brown, Paul D. , Peris‐Celda, Maria , Graffeo, Christopher S. , Link, Michael J., Oushy, Soliman H , Bauman, Megan M. J. , Gompel, Jamie J. Van , Link, Michael J.

Mayo Clinic

Neurosurgery | October 24, 2023 | Volume: 94 | Issue: 4 | Pages: 745-755

10.1227/neu.0000000000002735 | PMID 37874134 Get It

BACKGROUND AND OBJECTIVES: Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse. METHODS: A single-institution cohort study and systematic literature review of LCNS were performed. RESULTS: Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients. CONCLUSION: Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control—particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.
The longitudinal risk of hemorrhage of melanoma brain metastases after Gamma Knife radiosurgery
Hong, Sukwoo , Bouchal, Samantha M. , Riviere-Cazaux, Cécile , Pumford, Andrew D. , Brown, Paul D. , Yan, Elizabeth , Stafford, Scott L., Link, Michael J., Jusué-Torres, Ignacio , Pollock, Bruce E. , Jusue-Torres, Ignacio , Bouchal, Samantha M , Bauman, Megan M. J. , Markovic, Svetomir N. , Link, Michael J. , Burns, Terry C. , Parney, Ian F.

Mayo Clinic

Journal of Neurosurgery | September 30, 2023 | Volume: 140 | Issue: 4 | Pages: 938-948

10.3171/2023.7.jns231225 | PMID 37878000 Get It

OBJECTIVE The objective of this study was to analyze the hemorrhagic risk of melanoma brain metastases after Gamma Knife radiosurgery (GKRS). METHODS A prospective institutional database was retrospectively queried to identify patients who underwent GKRS for melanoma brain metastases between 1990 and 2021. Lesional hemorrhage was defined as definite or possible based on radiologists’ readings, and severity was graded according to Common Terminology Criteria for Adverse Events. RESULTS Two hundred ninety-one patients with 1083 lesions treated in 419 sessions were identified. The mean (± SD) patient age was 60 ± 15 years, and 61% were male. The median follow-up period for overall survival (OS) was 11 (range 0–214) months with 581 patient-years. Definite/possible lesional hemorrhages occurred in 13% of lesions, with grade 3 hemorrhages observed in 4% of lesions. Surgical intervention was required in 2% of cases (5% of patients), and all resected lesions were pathologically consistent with melanoma. A decreased risk of definite/possible lesional hemorrhage was associated with a later time period between 2015 and 2021 (OR 0.45, 95% CI 0.266–0.75, p = 0.0021), increased marginal dose (OR 0.91, 95% CI 0.83–0.99, p = 0.037), antiplatelet use post-GKRS (OR 0.195, 95% CI 0.083–0.46, p < 0.001), and whole-brain radiotherapy (WBRT; OR 0.53, 95% CI 0.344–0.82, p = 0.0042). After 2015, more patients received anticoagulation, B-Raf proto-oncogene inhibitors, and immune checkpoint inhibitors, and fewer received bevacizumab (p < 0.001). The cumulative risk of lesional hemorrhage was 17%–20% at 36 months from GKRS, with 95%–96% of cases occurring within 12 months. The median patient OS was 11 (95% CI 9–13) months, and multivariate Cox regression analysis revealed that antiplatelet agents (hazard ratio [HR] 0.66, 95% CI 0.45–0.96, p = 0.031) and immune checkpoint inhibitors (HR 0.35, 95% CI 0.26–0.48, p < 0.001) were associated with longer OS, while WBRT (HR 1.36, 95% CI 1.02–1.81, p = 0.037) and definite/possible hemorrhage (HR 1.39, 95% CI 1.04–1.85, p = 0.024) were associated with shorter OS. CONCLUSIONS The definite hemorrhage risk of melanoma brain metastases after GKRS was 17% in the first 3 years and 95% of the lesional hemorrhage occurred within the 1st year. Surgical intervention was needed in 5% of patients. Antiplatelet agents and immune checkpoint inhibitors were associated with improved OS, while definite/possible hemorrhage was associated with worse OS.
Spectral flow cytometry identifies distinct nonneoplastic plasma extracellular vesicle phenotype in glioblastoma patients
Aibaidula, Abudumijiti, Fain, Cori E. , Garcia, Luz Cumba, Wier, Annelise, Bouchal, Samantha M. , Jung, M. Katherine , Johnson, Aaron J. , Parney, Ian F. , Aibaidula, Abudumijiti Zack, Jung, Mi-Yeon, Parney, Ian F , Bouchal, Samantha M , Bauman, Megan M. J. , Sarkaria, Jann N. , Johnson, Aaron J.

Mayo Clinic

Neuro-Oncology Advances | July 5, 2023 | Volume: 5 | Issue: 1 | Pages: No page available

10.1093/noajnl/vdad082 | PMID 37638345 Get It

Abstract Background Glioblastoma (GBM) is the most common malignant brain tumor and has a poor prognosis. Imaging findings at diagnosis and in response to treatment are nonspecific. Developing noninvasive assays to augment imaging would be helpful. Plasma extracellular vesicles (EVs) are a promising biomarker source for this. Here, we develop spectral flow cytometry techniques that demonstrate differences in bulk plasma EV phenotype between GBM patients and normal donors that could serve as the basis of a liquid biopsy. Methods Plasma EVs were stained for EV-associated tetraspanins (CD9/CD63/CD81), markers indicating cell of origin (CD11b/CD31/CD41a/CD45), and actin/phalloidin (to exclude cell debris). EVs were analyzed using spectral flow cytometry. Multiparametric analysis using t-distributed stochastic neighbor embedding (t-SNE) and self-organizing maps on flow cytometry data (FlowSOM) was performed comparing GBM and normal donor (ND) plasma EVs. Results Size exclusion chromatography plus spectral-based flow cytometer threshold settings enriched plasma EVs while minimizing background noise. GBM patients had increased CD9+, CD63+, CD81+, and myeloid-derived (CD11b+) EVs. Multiparametric analysis demonstrated distinct surface marker expression profiles in GBM plasma EVs compared to ND EVs. Fifteen plasma EV sub-populations differing in size and surface marker expression were identified, six enriched in GBM patients and two in normal donors. Conclusions Multiparametric analysis demonstrates that GBM patients have a distinct nonneoplastic plasma EV phenotype compared to ND. This simple rapid analysis can be performed without purifying tumor EVs and may serve as the basis of a liquid biopsy.
Predicting disease progression and the need for tumor-directed treatment in tectal plate gliomas
Giesken, Max B. , Naylor, Ryan M. , Keating, Gesina F. , Schwartz, Jonathan , Schwartz, Jonathan D. , Bauman, Megan M. J. , Daniels, David J.

Mayo Clinic

Journal of Neurosurgery: Pediatrics | June 18, 2023 | Volume: 32 | Issue: 3 | Pages: 332-342

10.3171/2023.4.peds22485 | PMID 37347621 Get It

OBJECTIVE Tectal plate gliomas are rare, slow-growing tumors of the midbrain that are discovered predominantly in the pediatric population. Because of their indolent nature, treatment mainly consists of observation and management of hydrocephalus. Unfortunately, a subset of tectal gliomas may exhibit tumor enlargement and disease progression. Currently, there are no established guidelines for predicting future progression of tectal gliomas or the need for tumor-directed treatment. In this paper, the authors present a large case series of tectal plate gliomas with the aim of determining early indicators of tumor progression and the need for tumor-directed treatment in a pediatric population, along with providing their experience in treating progressive tumors. METHODS A retrospective chart review of 170 patients diagnosed with tectal plate glioma from a single institution, of whom 67 were pediatric patients (≤ 18 years of age), was performed. Univariate analysis was used to determine statistically significant predictors of symptomatic disease progression requiring eventual tumor-directed therapy. RESULTS The median patient age of the full cohort was 24 years (range 0–73 years). Compared with the pediatric population, the adult population had more instances of incidental lesions (p < 0.001) and lower rates of hydrocephalus (50% vs 84%, p < 0.001). Of the pediatric patients who had ≥ 5 years of follow-up (n = 51), 12 (24%) experienced radiological progression and 13 (25%) required treatment for their tumor. The 1-year, 5-year, and 10-year radiographic progression-free survival (PFS) rates were 98%, 90%, and 86%, respectively. In univariate analysis, lesion involvement of the pons, moderate T1 hypointensity, and moderate contrast enhancement on baseline radiology were significantly associated with worse radiographic PFS. Alternatively, significant predictors of requiring tumor-directed treatment included extraocular eye movement abnormalities at presentation, involvement of the lesion beyond the tectum on baseline radiology, moderate T1 hypointensity, moderate contrast enhancement, and an increase in total lesion size during progression. At the most recent follow-up, 94% of the patients had stable/nonprogressive disease, 2% had progressive disease, and 4% died of tumor progression. CONCLUSIONS Patients who demonstrate radiographic progression may not necessarily experience clinical/symptomatic progression or require tumor-directed treatment. Certain patient presentation characteristics and baseline radiographic features may be predictive of worse radiographic PFS or the need for future tumor-directed treatment in the pediatric population. Typically, the natural history of these lesions lends to excellent long-term survival, even in patients who experience clinical progression, should appropriate treatment be initiated.
Commentary: Endoscope-Assisted Microsurgical Resection of a Large Petroclival Meningioma Through a Retrosigmoid Approach: 2-Dimensional Operative Video
Bauman, Megan M. J. , Michaelcheck, Charlotte E., Patra, Devi Prasad, Patra, Devi P. , Bauman, Megan , Bendok, Bernard R.

Mayo Clinic

Operative Neurosurgery | May 11, 2023 | Volume: 24 | Issue: 6 | Pages: e463-e465

10.1227/ons.0000000000000691 | PMID 37166198 Get It

Bone morphogenetic proteins in spine surgery: a scientometric analysis to date
Shoushtari, Ali , Durrani, Sulaman , Bydon, Mohamad , Bauman, Megan M. J. , Nathani, Karim Rizwan

Mayo Clinic

Journal of Neurosurgery: Spine | May 6, 2023 | Volume: 39 | Issue: 2 | Pages: 271-277

10.3171/2023.4.spine221029 | PMID 37148222 Get It

OBJECTIVE Bone morphogenetic proteins (BMPs) are part of the transforming growth factor–beta superfamily and are involved in bone formation and repair. In spine surgery, recombinant human BMP (rhBMP) is used as an alternative to autografts for spinal fusions. This study aimed to evaluate bibliometric parameters and citations of the literature on BMPs to provide an overview of how the field has evolved. METHODS A comprehensive search of the literature was conducted using Elsevier’s Scopus database to capture all the published and indexed studies relevant to BMPs from 1955 to the present. A discrete set of validated bibliometric parameters was extracted and analyzed. All statistical analyses were performed using R 4.1.1. RESULTS The 100 most cited articles were published between 1994 and 2018 by 472 unique authors in 40 sources (e.g., journals and books). On average, there were 279 citations per publication and 17.69 citations per publication per year. The United States had the publications with the most citations (n = 23,761), followed by Hong Kong (n = 580) and the United Kingdom (n = 490). The three institutions in the United States with the greatest number of publications in the field were Emory University (n = 14), Hughston Clinic (n = 9), Hospital for Special Surgery (n = 6), and University of California (n = 6). CONCLUSIONS The authors evaluated and characterized the 100 most cited articles about BMP. Most of the publications were clinical in nature and focused on BMP’s application in spine surgery. While early scientific efforts focused on basic science research to advance the understanding of BMP’s mechanism of action in promoting bone formation, the majority of the more recent publications are clinically focused. It will be beneficial to conduct more controlled clinical trials to compare the outcomes of BMP use with other methods.
Abstract Number ‐ 282: Surgical Treatment for Moyamoya Disease with Coexisting Autoimmune Conditions: A Systematic Review
Harrison, Daniel , Quiñones‐Hinojosa, Alfredo , Gottfried, Oren N., Brown, Nolan J. , Singh, Rohin , Bauman, Megan M. J. , Seas, Andreas , Shahrestani, Shane , Grant, Gerald A.

Mayo Clinic

Stroke: Vascular and Interventional Neurology | April 25, 2023 | Volume: 3 | Issue: S1 | Pages: No page available

10.1161/svin.03.suppl_1.282 Get It

Introduction There have been several studies of Moyamoya disease (MMD) with concurrent autoimmune (AI) disease. It has been proposed that there may be a causal or synergistic effect of autoimmune and inflammatory conditions in patients with MMD. As such, in the present study we seek to characterizethe surgical outcomes of adults and children with MMD and coexisting AI conditions. Methods A systematic review was performed of published studies reporting patient level data of Moyamoya disease and concomitant autoimmune disease. Relevant studies were identified using Preferred reporting Items for Systematic Reviews and Meta‐Analysis criteria. Results A total of 149 studies were included, encompassing 257 patients. Of the 257 patients with concurrent AI and MMD, 107 (88 females, 19 males) underwent surgery. The average age was 31.3 years (Range 5–65; SD 12.5). Five cases presented with hemorrhagic symptoms, 87 ischemic, and 15 were unspecified. The most commonly associated AI conditions were Graves’ disease (71 cases, 66.4%), Lupus (17 cases, 15.9%), and T1DM (6 cases, 5.6%).Follow‐up was reported in 25 cases and was an average of 17.8 months. Surgical outcomes were reported in 82 cases; 63 (76.8%) improved, 7 (8.5%) were stable, 9 (10.9%) developed a new deficit, and 3 (3.7%) died at most recent follow up. Eight patients (7.5%) had disease progression. 63 (58.8%) patients were treated with additional autoimmune therapy although this therapy did not lead to any difference in outcomes. Twenty patients (18.7%) required additional supportive medical therapy (eg: aspirin, statins). Conclusions Moyamoya disease may be multifactorial. Patients with concomitant AI and Moyamoya disease may be at increased risk and warrant additional surveillance or intervention. The ideal therapy for these patients remains to be understood. These findings warrant further study into optimal diagnostic and therapeutic techniques for concomitant MMD and AI conditions.
Abstract Number ‐ 281: Clinical and Epidemiological Characteristics of Moyamoya Disease Presenting with Concomitant Autoimmune Conditions
Harrison, Daniel , Gottfried, Oren N., Brown, Nolan J. , Singh, Rohin , Bauman, Megan M. J. , Seas, Andreas , Shahrestani, Shane , Gendreau, Julian

Mayo Clinic

Stroke: Vascular and Interventional Neurology | April 25, 2023 | Volume: 3 | Issue: S1 | Pages: No page available

10.1161/svin.03.suppl_1.281 Get It

Introduction Moyamoya disease was first described in the 1950’s. After over six decades, however, the underlying etiology of Moyamoya still remains unknown. It has been postulated that underlying inflammatory or autoimmune (AI) processes may play a role in the development of this condition. In order to further investigate this hypothesis, we studied the clinical and epidemiological attributes of patients with concurrent Moyamoya disease and AI condition(s). Methods A systematic review was performed including studies reporting patient level data of Moyamoya disease and concomitant autoimmune disease. Relevant studies were identified using Preferred reporting Items for Systematic Reviews and Meta‐Analysis criteria. Results There were 739 results of which 149 were included in this study. The first reports of concurrent Moyamoya and AI occurred in 1991 and involved 2 cases of Moyamoya and associated Graves’ disease. These patients were treated with antithyroid medication alone and showed improvement. Altogether, our search yielded a total of 257 patients (192 females, 48 males, 17 unspecified). A total of 158 cases were reported as “Moyamoya Disease” and 99 were reported as “Moyamoya Syndrome/Vasculopathy.” Most cases were ischemic (175 ischemic, 15 hemorrhagic) in nature. Bilaterality of the disease was reported in 130 cases, unilaterality in 34 cases. The most commonly reported ethnicity was Chinese (26 cases), followed by Japanese (17 cases), and Korean (17 cases). The most common co‐presenting AI conditions were Graves’ disease (150 cases, 58.4%), Lupus (26 cases, 10.1%), antiphospholipid syndrome (19 cases, 7.4%), Type 1 Diabetes (19 cases, 7.4%), and Multiple Sclerosis (7 cases, 2.7%). Conclusions There are numerous reports describing patients diagnosed with Moyamoya in addition to coexisting AI conditions. Our study shows that the demographic characteristics of co‐presentation align with the common autoimmune (female predominance) and Moyamoya (high east Asian prevalence) attributes. These results warrant further investigation into a possible causal or synergistic relationship between Moyamoya and AI disease.