Bendok, Bernard R.

Abstract High grade gliomas (HGGs) are aggressive brain tumors that are difficult to remove completely, leading to poor survival rates. Contrast enhancement on T1Gd magnetic resonance imaging (MRI) has traditionally been used to guide resection, however it often underestimates true tumor burden, adding a layer of uncertainty for surgeons during pre-operative planning. Fluorescence guided surgery using 5-aminolevulinic acid (5-ALA) has emerged as an intraoperative solution and understanding it in conjunction with MRI features can address the limitations of routine T1Gd imaging during surgical planning. Here we investigate sex-specific patterns in HGGs using 5-ALA fluorescence and imaging features. We analyzed a patient dataset of 202 multiregional MRI-localized biopsies from 42 HGG patients (20 male and 22 female). Data included patient demographics, 5-ALA status (positive or negative), MRI annotations (CE = contrast enhancement, NE = non-enhancement, BAT = brain around tumor non-enhancement), and survival outcomes. Statistical analyses included Wilcoxon rank-sum tests, Kruskal-Wallis tests, and chi-squared tests to assess differences in imaging annotations and 5-ALA positive vs negative status among sex cohorts. Among all samples, CE and BAT were associated with higher 5-ALA positivity, while NE was associated with higher 5-ALA negativity (p = 0.02119). Female patients were less likely to have detectable 5-ALA in their multiregional biopsy samples than males (p < 0.0001). CE at the biopsy location was more likely to be indicative of 5-ALA positivity in males than females (p = 0.001927); whereas NE was associated with higher 5-ALA negativity in females than males (p = 0.03426). BAT was associated with higher 5-ALA positivity in males than females (p = 0.03895). Our study reveals sex-specific patterns in 5-ALA fluorescence and image features among HGG patients. These unique features may serve as potential pre-surgical markers for tumor regions that are more likely to benefit from 5-ALA-guided resection.

Abstract The intra- and inter-patient heterogeneity in high-grade glioma (HGG) continues to contribute to its poor prognosis. Clinical biopsies are often harvested from limited regions and typically are not image localized. Thus, they fail to capture the diversity within tumor regions, immune expression or normal cell abundances that play key roles in tumor development. It is important to gain an understanding of these subpopulation ecologies, their spatial resolution, and interactions between them that may then be exploited for future therapeutic benefit. Further, these may differ by patient characteristics such as sex, age at diagnosis and treatment status. Using an ongoing image-localized biopsy collection protocol, we have so far evaluated the bulk transcriptomics of 202 multi-regional biopsies from 58 patients to characterize HGG heterogeneity. These samples were processed through Monocle, a reverse graph embedding algorithm that groups samples into states and orders them along developmental trajectories. Deconvolution methods were previously used to predict relative abundances of 7 normal, 6 glioma, and 5 immune cell subpopulations for each sample, which we have now overlaid on the Monocle graph. Monocle classified HGG into 4 main states along a three-pronged trajectory. These states reveal distinct population ecologies with associated enriched gene pathways. We also note significant immune pathway enrichments that differ between state and patient-reported sex. Together, these algorithms reveal a simple transcriptomic trajectory that helps us understand the development and evolution of HGG. Characterizing the in vivo diversity within and between high grade gliomas is important for understanding prognosis, stratifying future treatments and ultimately improving patient outcome.

Abstract Magnetic resonance imaging (MRI) is key to clinically managing brain tumor patients, however connecting the biology to imaging remains challenging. We previously developed a two-compartment model of MRI signal intensity to quantitatively estimate relative edema abundance from T2-weighted MRIs. Using this model, we previously identified the fatty acid metabolism (FAM) and oxidative phosphorylation (OxPhos) pathways as sex-distinct, with both pathways amplified for high edema in males and low edema in females. The purpose of this project was to further delineate sex-distinct biology associated with MRI-estimated brain tumor edema abundance. We analyzed 179 multiregional samples (Female: 75; Male: 104) from 55 high grade glioma patients (Female: 21; Male: 34) for bulk RNA-Seq. Patients’ pre-surgical multiparametric MRIs were preprocessed and segmented for abnormal regions and normal tissue. Utilizing the segmentations and preprocessed images we estimated the relative fractions of extracellular and intracellular space based on the edema mathematical model. Samples were characterized by their edema scores, which were analyzed using differential expression for high and low edema, gene set enrichment analysis (GSEA) using MSigDB hallmarks, and leading edge interpretation. Based on transcriptomic leading edge analyses of high and low edema samples from sex-separated cohorts, we identified common and sex-distinct enrichment of the FAM and OxPhos pathways underlying edema patterns. Of the OxPhos pathway leading edge genes, 45 were common, 36 were unique to females, and 66 were unique to males. Of the FAM pathway leading edge genes, 8 were common, 39 were unique to females, and 29 were unique to males. Notably, expression of both IDH1 and IDH2 were increased for males in regions of high edema in the OxPhos pathway. IDH3a was decreased for females in regions of low edema in the OxPhos pathway. These data suggest that there may be sex-distinct metabolism underlying MRI measurable edema formation.

Abstract Accurate response assessment in patients with high-grade gliomas (HGGs) is complicated by post-treatment radiographic changes that are equivocal for treatment effect versus progression. Plasma-based liquid biopsy assays for circulating tumor DNA (ctDNA) have had limited sensitivity to date, due in part to the presence of the blood-brain barrier that limits the diffusion of tumor-derived analytes out of the central nervous system. To address this challenge, we developed a ctDNA plasma-based assay to detect individualized tumor-derived amplified junctions in patients with HGGs. These junctions occur due to large-scale chromosomal rearrangements, such as those associated with epidermal growth factor receptor (EGFR) or cyclin-dependent kinase 4 (CDK4) amplification. To identify these amplified junctions, whole genome sequencing was performed on resected tissue. Primers were designed to flank junction breakpoints and were then utilized on each patient’s plasma samples to detect the amplified junction via qPCR. Tumor-specific amplified junctions were robustly detected in plasma from 14/14 (100%) patients with IDH-mutant or wild-type grade 4 astrocytomas whose tumor genomes demonstrated amplification-related junctions, located at chromosomes 7, 11, or 12. In comparison, ctDNA could not be detected in three control cases that did not have an amplification or did not have high copy number junctions. Importantly, serial plasma samples obtained prior to and at disease recurrence in 4 patients demonstrated an increasing abundance of amplified junctions that accurately correlated with disease progression in 4/4 patients (100%). In two of these patients, increasing abundance of amplified junctions preceded radiographic changes compatible with disease progression by approximately 2 or 4 months, respectively. In conclusion, tumor-specific amplified junctions could reliably be detected in plasma from patients with IDH-mutant or wild-type grade 4 astrocytomas and correlated with changes in disease burden. Further work is currently ongoing to evaluate these promising results in a larger cohort of patients with serial plasma samples.

Abstract BACKGROUND Leptomeningeal disease (LMD) carries poor prognosis with an average survival of 3-6 months after diagnosis. Ommaya reservoirs (OR) are an accessible alternative to serial lumbar punctures for delivery of intrathecal chemotherapy (IC) and disease monitoring but are not widely used. Intraventricular administration of chemotherapy may be associated with superior efficacy and improved patient comfort. The purpose of this study was to assess safety and efficacy of IC and disease monitoring via OR in routine clinical practice. MATERIAL AND METHODS Patients who received at least one administration of IC via OR for LMD between 2017 and 2022 were included. Demographics, treatment type, complications and outcomes were recorded. RESULTS We identified 22 patients (17 females, 5 males) with mean age 50.9 ± 14.8 years. The primary tumors were: breast (12), leukemia (3), ovarian carcinoma (3), CNS lymphoma (1), urothelial carcinoma (1), spinal melanocytoma (1), and high-grade glioma (1). A total of 208 OR injections were performed [median was 9 OR injections per patient, interquartile range (IQR) (5, 13)]. Five patients (23%) experienced mild adverse events of grade 2 or lower by Common Terminology Criteria for Adverse Events. Overall risk of adverse event from injection was 3.4% (7/208). Eight patients (36.3%) converted into negative CSF cytology (median 1 month following first injection), and 18 patients (82%) had clinical or radiological progression of their LMD (median 2 months following first injection). Eleven patients (50%) died of their LMD during follow-up. Median OS and PFS from the first injection were 5.3 months [95% CI 4.8-NE (not estimable)] and 4.3 months [95% CI 1.8-16.0], respectively. CONCLUSION Use of OR in routine clinical practice is a safe and feasible option and should be strongly considered for treatment and frequent disease monitoring of patients with LMD, especially in the era of circulating tumor cells analysis. The median OS in our cohort is comparable to prior published series.

AbstractThe study objective was to compare the length of stay (LOS) and the proportion of one-night admissions before and after the implementation of an endocrine monitoring protocol following endoscopic transsphenoidal surgery (ETSS) for pituitary adenoma.Patients who underwent transsphenoidal pituitary adenoma resection between July 1, 2018, and September 9, 2022, were identified, and divided into two cohorts before and after the implementation of the monitoring protocol. The overall LOS and number of nights of admission were recorded. Readmission within 30 days after surgery was also recorded. The number of outpatient laboratory tests performed and the time to the first test were also noted.Thirty patients were identified in the preprotocol group and 60 in the postprotocol group. The average admission length in the preprotocol group was significantly longer than the average admission length in the postprotocol group (2.4 vs. 1.7 days, p = 0.004). The percentage of one-night admissions increased from 13 to 57% (p < 0.001). There were no significant differences in readmission rates between the two groups (p = 0.681). The number of laboratory encounters increased from a mean of 1.38 to 2.40 (p = 0.030), while the time to the first test decreased from a mean of 3.43 to 2.36 days (p = 0.049).Patients admitted after ETSS for pituitary adenoma had shorter hospital stay and greater proportion of one-night admission with the implementation of an endocrine monitoring protocol. The all-cause readmission rate was not statistically different between the two groups. Through aggressive outpatient laboratory monitoring, one-night admission for ETSS may be feasible.

BACKGROUND: Smoking and observed growth of intracranial aneurysms are known risk factors for rupture. The mechanism by which smoking increases this risk is not completely elucidated. Furthermore, an association between smoking and aneurysm growth has not been clearly defined in the literature. We hypothesize that smoking is associated with aneurysm growth, which, in turn, may serve as one of the mechanisms by which smoking drives rupture risk. METHODS: We report a systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Using the R software, we performed a meta-analysis to investigate the association between smoking and the growth of unruptured intracranial aneurysms. Studies on familial aneurysms and genetic syndromes known to increase the risk of aneurysms were excluded. RESULTS: Eighteen observational studies were included with a total of 3535 patients and 4289 aneurysms with a mean follow-up period ranging from 17 to 226 months. The mean age among the studies ranged from 38.4 to 73.9 years; 74% of patients were female. Ever-smoking status (odds ratio, 1.10 [95% CI, 0.87–1.38]) and current smoking status (odds ratio, 1.43 [95% CI, 0.84–2.43]) did not show a statistically significant association with growth of intracranial aneurysms. Patients currently smoking did not have a statistically significant association with the growth of intracranial aneurysms (odds ratio, 1.18 [95% CI, 0.72–1.93]) compared with patients without a smoking history. No significant association was found in patients who previously smoked compared with patients who never smoked (odds ratio, 1.46 [95% CI, 0.88–2.43]). CONCLUSIONS: Smoking is not clearly associated with the growth of unruptured intracranial aneurysms, despite trends being observed, there is no statistical association. The mechanism by which smoking increases rupture risk might not be growth. In patients for whom observation is recommended, the absence of growth over time in the setting of smoking history does not, therefore, imply protection from rupture.