The effect of IDH1 mutation on the structural connectome in malignant astrocytoma

Connectomic insights into the impact of 1p/19q co-deletion in dominant hemisphere insular glioma patients

Objectives

This study aimed to elucidate the influences of 1p/19q co-deletion on structural connectivity alterations in patients with dominant hemisphere insular diffuse gliomas.

Methods

We incorporated 32 cases of left insular gliomas and 20 healthy controls for this study. Using diffusion MRI, we applied correlational tractography, differential tractography, and graph theoretical analysis to explore the potential connectivity associated with 1p/19q co-deletion.

Results

The study revealed that the quantitative anisotropy (QA) of key deep medial fiber tracts, including the anterior thalamic radiation, superior thalamic radiation, fornix, and cingulum, had significant negative associations with 1p/19q co-deletion (FDR = 4.72 × 10-5). These tracts are crucial in maintaining the integrity of brain networks. Differential analysis further supported these findings (FWER-corrected p < 0.05). The 1p/19q non-co-deletion group exhibited significantly higher clustering coefficients (FDR-corrected p < 0.05) and reduced betweenness centrality (FDR-corrected p < 0.05) in regions around the tumor compared to HC group. Graph theoretical analysis indicated that non-co-deletion patients had increased local clustering and decreased betweenness centrality in peritumoral brain regions compared to co-deletion patients and healthy controls (FDR-corrected p < 0.05). Additionally, despite not being significant through correction, patients with 1p/19q co-deletion exhibited lower trends in weighted average clustering coefficient, transitivity, small worldness, and global efficiency, while showing higher tendencies in weighted path length compared to patients without the co-deletion.

Conclusion

The findings of this study underline the significant role of 1p/19q co-deletion in altering structural connectivity in insular glioma patients. These alterations in brain networks could have profound implications for the neural functionality in patients with dominant hemisphere insular gliomas.

Brain network topology and its cognitive impact in adult glioma survivors

Structural brain network topology can be altered in case of a brain tumor, due to both the tumor itself and its treatment. In this study, we explored the role of structural whole-brain and nodal network metrics and their association with cognitive functioning. Fifty WHO grade 2-3 adult glioma survivors (> 1-year post-therapy) and 50 matched healthy controls underwent a cognitive assessment, covering six cognitive domains. Raw cognitive assessment scores were transformed into w-scores, corrected for age and education. Furthermore, based on multi-shell diffusion-weighted MRI, whole-brain tractography was performed to create weighted graphs and to estimate whole-brain and nodal graph metrics. Hubs were defined based on nodal strength, betweenness centrality, clustering coefficient and shortest path length in healthy controls. Significant differences in these metrics between patients and controls were tested for the hub nodes (i.e. n = 12) and non-hub nodes (i.e. n = 30) in two mixed-design ANOVAs. Group differences in whole-brain graph measures were explored using Mann-Whitney U tests. Graph metrics that significantly differed were ultimately correlated with the cognitive domain-specific w-scores. Bonferroni correction was applied to correct for multiple testing. In survivors, the bilateral putamen were significantly less frequently observed as a hub (pbonf < 0.001). These nodes' assortativity values were positively correlated with attention (r(90) > 0.573, pbonf < 0.001), and proxy IQ (r(90) > 0.794, pbonf < 0.001). Attention and proxy IQ were significantly more often correlated with assortativity of hubs compared to non-hubs (pbonf < 0.001). Finally, the whole-brain graph measures of clustering coefficient (r = 0.685), global (r = 0.570) and local efficiency (r = 0.500) only correlated with proxy IQ (pbonf < 0.001). This study demonstrated potential reorganization of hubs in glioma survivors. Assortativity of these hubs was specifically associated with cognitive functioning, which could be important to consider in future modeling of cognitive outcomes and risk classification in glioma survivors.

Perioperative Neurocognitive Function in Glioma Surgery

PURPOSE OF REVIEW

This review provides a concise overview of the recent literature regarding preoperative and postoperative neurocognitive functioning (NCF) in patients with glioma. Brief discussion also covers contemporary intraoperative brain mapping work, with a focus on potential influence of mapping upon NCF outcomes following awake surgery.

RECENT FINDINGS

Most patients with glioma exhibit preoperative NCF impairment, with severity varying by germ line and tumoral genetics, tumor grade, and lesion location, among other characteristics. Literature regarding postoperative NCF changes is mixed, though numerous studies indicate a majority of patients exhibit immediate and short-term worsening. This is often followed by recovery over several months; however, a substantial portion of patients harbor persisting declines. Decline appears related to surgically-induced structural and functional brain alterations, both local and distal to the tumor and resection cavity. Importantly, NCF decline may be mitigated to some extent by intraoperative brain mapping, including mapping of both language-mediated and nonverbal functions. Research regarding perioperative NCF in patients with glioma has flourished over recent years. While this has increased our understanding of contributors to NCF and risk of decline associated with surgical intervention, more work is needed to better preserve NCF throughout the disease course.

Strength of spatial correlation between gray matter connectivity and patterns of proto-oncogene and neural network construction gene expression is associated with diffuse glioma survival

Introduction

Like other forms of neuropathology, gliomas appear to spread along neural pathways. Accordingly, our group and others have previously shown that brain network connectivity is highly predictive of glioma survival. In this study, we aimed to examine the molecular mechanisms of this relationship via imaging transcriptomics.

Methods

We retrospectively obtained presurgical, T1-weighted MRI datasets from 669 adult patients, newly diagnosed with diffuse glioma. We measured brain connectivity using gray matter networks and coregistered these data with a transcriptomic brain atlas to determine the spatial co-localization between brain connectivity and expression patterns for 14 proto-oncogenes and 3 neural network construction genes.

Results

We found that all 17 genes were significantly co-localized with brain connectivity (p < 0.03, corrected). The strength of co-localization was highly predictive of overall survival in a cross-validated Cox Proportional Hazards model (mean area under the curve, AUC = 0.68 +/- 0.01) and significantly (p < 0.001) more so for a random forest survival model (mean AUC = 0.97 +/- 0.06). Bayesian network analysis demonstrated direct and indirect causal relationships among gene-brain co-localizations and survival. Gene ontology analysis showed that metabolic processes were overexpressed when spatial co-localization between brain connectivity and gene transcription was highest (p < 0.001). Drug-gene interaction analysis identified 84 potential candidate therapies based on our findings.

Discussion

Our findings provide novel insights regarding how gene-brain connectivity interactions may affect glioma survival.

Molecular Determinants of Neurocognitive Deficits in Glioma: Based on 2021 WHO Classification

Cognitive impairment is a common feature among patients with diffuse glioma. The objective of the study is to investigate the relationship between preoperative cognitive function and clinical as well as molecular factors, firstly based on the new 2021 World Health Organization's updated classification of central nervous system tumors. A total of 110 diffuse glioma patients enrolled underwent preoperative cognitive assessments using the Mini-Mental State Examination and Montreal Cognitive Assessment. Clinical information was collected from medical records, and gene sequencing was performed to analyze the 18 most influenced genes. The differences in cognitive function between patients with and without glioblastoma were compared under both the 2016 and 2021 WHO classification of tumors of the central nervous system to assess their effect of differentiation on cognition. The study found that age, tumor location, and glioblastoma had significant differences in cognitive function. Several genetic alterations were significantly correlated with cognition. Especially, IDH, CIC, and ATRX are positively correlated with several cognitive domains, while most other genes are negatively correlated. For most focused genes, patients with a low number of genetic alterations tended to have better cognitive function. Our study suggested that, in addition to clinical characteristics such as age, histological type, and tumor location, molecular characteristics play a crucial role in cognitive function. Further research into the mechanisms by which tumors affect brain function is expected to enhance the quality of life for glioma patients. This study highlights the importance of considering both clinical and molecular factors in the management of glioma patients to improve cognitive outcomes.

Exploring MGMT methylation-driven structural connectivity changes in insular gliomas: a tractography and graph theoretical analysis

OBJECTIVES

This study aims to explore the relationship between the methylation levels of the O-6-methylguanine-DNA methyltransferase (MGMT) promoter and the structural connectivity in insular gliomas across hemispheres.

METHODS

We analyzed 32 left and 29 right insular glioma cases and 50 healthy controls, using differential tractography, correlational tractography, and graph theoretical analysis to investigate the correlation between structural connectivity and the methylation level.

RESULTS

The differential tractography results revealed that in left insular glioma, the volume of affected inferior fronto-occipital fasciculus (IFOF, p = 0.019) significantly correlated with methylation levels. Correlational tractography results showed that the quantitative anisotropy (QA) value of peritumoral fiber tracts also exhibited a significant correlation with methylation levels (FDR < 0.05). On the other hand, in right insular glioma, anterior internal part of the reticular tract, IFOF, and thalamic radiation showed a significant correlation with methylation levels but at a different correlation direction from the left side (FDR < 0.05). The graph theoretical analysis showed that in the left insular gliomas, only the radius of graph was significantly lower in methylated MGMT group than unmethylated group (p = 0.047). No significant correlations between global properties and methylation levels were observed in insular gliomas on both sides.

CONCLUSION

Our findings highlight a significant, hemisphere-specific correlation between MGMT promoter methylation and structural connectivity in insular gliomas. This study provides new insights into the genetic influence on glioma pathology, which could inform targeted therapeutic strategies.

Cognitive functioning is prognostic in patients with IDH1-wild type and MGMT-unmethylated high-grade gliomas

AIM

To investigate the prognostic factors of survival in patients with high-grade gliomas without isocitrate dehydrogenase-1 (IDH) mutation and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation.

METHODS

The study enrolled Slovenian patients with high-grade gliomas. Postoperatively, they completed a battery of neuropsychological tests. Demographics and clinical data were collected. The results of cognitive tests were converted to standardized scores and dichotomized based on impairment. A univariate Cox proportional hazard regression model was used to determine clinical predictors, and a multivariate Cox model was used to determine the prognostic value of cognitive test results. Kaplan-Meier curves were constructed, and survival was compared with the log rank test.

RESULTS

The study enrolled 49 patients with IDH wild-type, MGMT-unmethylated high-grade gliomas. The median time to progression was 9.92 months (7.25, 12.59) and the overall median survival was 12.19 months (8.95, 15.4). Age and the extent of surgery were significant prognostic factors for survival. After controlling for these factors, cognitive functioning in the domain of verbal fluency remained a significant predictor of survival outcomes.

CONCLUSION

Cognitive functioning in the domain of verbal fluency was associated with overall survival independently of age and the extent of surgery. Cognitive functioning could be an important stratifying tool in this group of patients lacking other predictors.

Strength of spatial correlation between structural brain network connectivity and brain-wide patterns of proto-oncogene and neural network construction gene expression is associated with diffuse glioma survival

Like other forms of neuropathology, gliomas appear to spread along neural pathways. Accordingly, our group and others have previously shown that brain network connectivity is highly predictive of glioma survival. In this study, we aimed to examine the molecular mechanisms of this relationship via imaging transcriptomics. We retrospectively obtained presurgical, T1-weighted MRI datasets from 669 adult patients, newly diagnosed with diffuse glioma. We measured brain connectivity using gray matter networks and coregistered these data with a transcriptomic brain atlas to determine the spatial co-localization between brain connectivity and expression patterns for 14 proto-oncogenes and 3 neural network construction genes. We found that all 17 genes were significantly co-localized with brain connectivity (p < 0.03, corrected). The strength of co-localization was highly predictive of overall survival in a cross-validated Cox Proportional Hazards model (mean area under the curve, AUC = 0.68 +/- 0.01) and significantly (p < 0.001) more so for a random forest survival model (mean AUC = 0.97 +/- 0.06). Bayesian network analysis demonstrated direct and indirect causal relationships among gene-brain co-localizations and survival. Gene ontology analysis showed that metabolic processes were overexpressed when spatial co-localization between brain connectivity and gene transcription was highest (p < 0.001). Drug-gene interaction analysis identified 84 potential candidate therapies based on our findings. Our findings provide novel insights regarding how gene-brain connectivity interactions may affect glioma survival.

Advances in Imaging Modalities for Pediatric Brain and Spinal Cord Tumors

BACKGROUND

Neuroimaging has evolved from anatomical imaging toward a multi-modality comprehensive anatomical and functional imaging in the past decades, important functional data like perfusion-weighted imaging, permeability imaging, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI), tractography, metabolic imaging, connectomics, event-related functional imaging, resting state functional imaging, and much more is now being offered.

SUMMARY

Precision diagnostics has proven to be essential for precision treatment. Many minimal invasive techniques have been developed, taking advantage of digital subtraction angiography and interventional neuroradiology. Furthermore, intraoperative CT and/or MRI and more recently MR-guided focused ultrasound have complemented the diagnostic and therapeutic armamentarium.

KEY MESSAGES

In the current manuscript, we discuss standard imaging sequences including advanced techniques like DWI, DTI, susceptibility-weighted imaging, and 1H magnetic resonance spectroscopy, various perfusion weighted imaging approaches including arterial spin labeling, dynamic contrast enhanced imaging, and dynamic susceptibility contrast imaging. Pre-, intra, and postoperative surgical imaging including visualize imaging will be discussed. The value of connectomics will be presented for its value in neuro-oncology. Minimal invasive therapeutic possibilities of interventional neuroradiology and image-guided laser ablation and MR-guided high-intensity-focused ultrasound will be presented for treatment of pediatric brain and spinal cord tumors. Finally, a comprehensive review of spinal cord tumors and matching neuropathology has been included.

The longitudinal relation between executive functioning and multilayer network topology in glioma patients

Many patients with glioma, primary brain tumors, suffer from poorly understood executive functioning deficits before and/or after tumor resection. We aimed to test whether frontoparietal network centrality of multilayer networks, allowing for integration across multiple frequencies, relates to and predicts executive functioning in glioma. Patients with glioma (n = 37) underwent resting-state magnetoencephalography and neuropsychological tests assessing word fluency, inhibition, and set shifting before (T1) and one year after tumor resection (T2). We constructed binary multilayer networks comprising six layers, with each layer representing frequency-specific functional connectivity between source-localized time series of 78 cortical regions. Average frontoparietal network multilayer eigenvector centrality, a measure for network integration, was calculated at both time points. Regression analyses were used to investigate associations with executive functioning. At T1, lower multilayer integration (p = 0.017) and epilepsy (p = 0.006) associated with poorer set shifting (adj. R2 = 0.269). Decreasing multilayer integration (p = 0.022) and not undergoing chemotherapy at T2 (p = 0.004) related to deteriorating set shifting over time (adj. R2 = 0.283). No significant associations were found for word fluency or inhibition, nor did T1 multilayer integration predict changes in executive functioning. As expected, our results establish multilayer integration of the frontoparietal network as a cross-sectional and longitudinal correlate of executive functioning in glioma patients. However, multilayer integration did not predict postoperative changes in executive functioning, which together with the fact that this correlate is also found in health and other diseases, limits its specific clinical relevance in glioma.

Cognitive reserve and individual differences in brain tumour patients

The aim of the paper is to determine the effects of the cognitive reserve on brain tumour patients' cognitive functions and, specifically, if cognitive reserve helps patients cope with the negative effects of brain tumours on their cognitive functions. We retrospectively studied a large sample of around 700 patients, diagnosed with a brain tumour. Each received an MRI brain examination and performed a battery of tests measuring their cognitive abilities before they underwent neurosurgery. To account for the complexity of cognitive reserve, we construct our cognitive reserve proxy by combining three predictors of patients' cognitive performance, namely, patients' education, occupation, and the environment where they live. Our statistical analysis controls for the type, side, site, and size of the lesion, for fluid intelligence quotient, and for age and gender, in order to tease out the effect of cognitive reserve on each of these tests. Clinical neurological variables have the expected effects on cognitive functions. We find a robust positive effect of cognitive reserve on patients' cognitive performance. Moreover, we find that cognitive reserve modulates the effects of the volume of the lesion: the additional negative impact of an increase in the tumour size on patients' performance is less severe for patients with higher cognitive reserve. We also find substantial differences in these effects depending on the cerebral hemisphere where the lesion occurred and on the cognitive function considered. For several of these functions, the positive effect of cognitive reserve is stronger for patients with lesions in the left hemisphere than for patients whose lesions are in the right hemisphere. The development of prevention strategies and personalized rehabilitation interventions will benefit from our contribution to understanding the role of cognitive reserve, in addition to that of neurological variables, as one of the factors determining the patients' individual differences in cognitive performance caused by brain tumours.

Cognitive functioning in a cohort of high-grade glioma patients

BACKGROUND

High grade gliomas are associated with cognitive problems. The aim of the study was to investigate cognitive functioning in a cohort of patients with high grade glioma, according to isocitrate dehydrogenase (IDH) and methyl guanine methyl transferase (MGMT) status and other clinical characteristics.

PATIENTS AND METHODS

The patients with the high-grade glioma treated in Slovenia in given period of time were included in study. Postoperatively they completed neuropsychological assessment consisting of Slovenian Verbal Learning Test, Slovenian Controlled Oral Word Association Test, Trail Making Test Part A and B and self-evaluation questionnaire. We analysed results (z-scores and dichotomized results) also according to IDH mutation and MGMT methylation. We examined differences between groups using T-test, Mann-Whitney U, χ² and Kendall's Tau tests.

RESULTS

Out of 275 patients in the cohort, we included 90. Forty-six percent of patients were unable to participate due to poor performance status and other conditions related to tumour. Patients with the IDH mutation were younger, with better performance status, larger proportions of grade III tumours and MGMT methylation. In this group cognitive functioning is significantly better in the domains of immediate recall, short delayed recall and delayed recall, and in the fields of executive functioning and recognition. There were no differences in cognitive functioning in regard to MGMT status. Grade III tumours were associated with more frequent MGMT methylation. Self-assessment proved week tool, associated only with immediate recall.

CONCLUSIONS

We found no differences in cognitive functioning according to MGMT status, but cognition was better when IDH mutation was present. In a cohort study of patients with high-grade glioma, almost half were unable to participate in a study, which points to an overrepresentation of patients with better cognitive functioning in the research.

Cognitive issues in patients with IDH mutant gliomas: from neuroscience to clinical neuropsychology

PURPOSE

The understanding of cognitive symptoms in patients with IDH-Mutant gliomas (IDH-Mut) is rapidly developing. In this article, we summarize the neuroscientific knowledge base regarding the influence of IDH-Mut tumors and their treatment on cognition and provide guidance regarding the management of these symptoms in patients.

METHODS

We performed a review of peer reviewed publications relevant to IDH-Mut glioma and cognitive outcomes and provide an overview of the literature as well as a case example to clarify management strategies.

RESULTS

At the time of presentation, patients with IDH-Mut gliomas have a favorable cognitive profile as compared with those with IDH-wild type (WT) tumors. The relatively low cognitive burden may reflect the slower growth rate of IDH-Mut tumors, which is less disruptive to both local and widespread neural networks. Human connectomic research using a variety of modalities has demonstrated relatively preserved network efficiency in patients with IDH-Mut gliomas as compared with IDH-WT tumors. Risk of cognitive decline from surgery can potentially be mitigated by careful integration of intra-operative mapping. Longer term cognitive risks of tumor treatment, including chemotherapy and radiation, are best managed by instituting neuropsychological assessment as part of the long-term care of patients with IDH-Mutant glioma. A specific timeline for such integrative care is provided.

CONCLUSIONS

Given the relative recency of the IDH-mutation based classification of gliomas, as well as the long time course of this disease, a thoughtful and comprehensive strategy to studying patient outcomes and devising methods of cognitive risk reduction is required.

Predicting overall survival in diffuse glioma from the presurgical connectome

Diffuse gliomas are incurable brain tumors, yet there is significant heterogeneity in patient survival. Advanced computational techniques such as radiomics show potential for presurgical prediction of survival and other outcomes from neuroimaging. However, these techniques ignore non-lesioned brain features that could be essential for improving prediction accuracy. Gray matter covariance network (connectome) features were retrospectively identified from the T1-weighted MRIs of 305 adult patients diagnosed with diffuse glioma. These features were entered into a Cox proportional hazards model to predict overall survival with 10-folds cross-validation. The mean time-dependent area under the curve (AUC) of the connectome model was compared with the mean AUCs of clinical and radiomic models using a pairwise t-test with Bonferroni correction. One clinical model included only features that are known presurgery (clinical) and another included an advantaged set of features that are not typically known presurgery (clinical +). The median survival time for all patients was 134.2 months. The connectome model (AUC 0.88 ± 0.01) demonstrated superior performance (P < 0.001, corrected) compared to the clinical (AUC 0.61 ± 0.02), clinical + (AUC 0.79 ± 0.01) and radiomic models (AUC 0.75 ± 0.02). These findings indicate that the connectome is a feasible and reliable early biomarker for predicting survival in patients with diffuse glioma. Connectome and other whole-brain models could be valuable tools for precision medicine by informing patient risk stratification and treatment decision-making.

Influences on cognitive outcomes in adult patients with gliomas: A systematic review

People with brain tumors, including those previously treated, are commonly affected by a range of neurocognitive impairments involving executive function, memory, attention, and social/emotional functioning. Several factors are postulated to underlie this relationship, but evidence relating to many of these factors is conflicting and does not fully explain the variation in cognitive outcomes seen in the literature and in clinical practice. To address this, we performed a systematic literature review to identify and describe the range of factors that can influence cognitive outcomes in adult patients with gliomas. A literature search was performed of Ovid MEDLINE, PsychINFO, and PsycTESTS from commencement until September 2021. Of 9,998 articles identified through the search strategy, and an additional 39 articles identified through other sources, 142 were included in our review. The results confirmed that multiple factors influence cognitive outcomes in patients with gliomas. The effects of tumor characteristics (including location) and treatments administered are some of the most studied variables but the evidence for these is conflicting, which may be the result of methodological and study population differences. Tumor location and laterality overall appear to influence cognitive outcomes, and detection of such an effect is contingent upon administration of appropriate cognitive tests. Surgery appears to have an overall initial deleterious effect on cognition with a recovery in most cases over several months. A large body of evidence supports the adverse effects of radiotherapy on cognition, but the role of chemotherapy is less clear. To contrast, baseline cognitive status appears to be a consistent factor that influences cognitive outcomes, with worse baseline cognition at diagnosis/pre-treatment correlated with worse long-term outcomes. Similarly, much evidence indicates that anti-epileptic drugs have a negative effect on cognition and genetics also appear to have a role. Evidence regarding the effect of age on cognitive outcomes in glioma patients is conflicting, and there is insufficient evidence for gender and fatigue. Cognitive reserve, brain reserve, socioeconomic status, and several other variables discussed in this review, and their influence on cognition and recovery, have not been well-studied in the context of gliomas and are areas for focus in future research.

Alternations and Applications of the Structural and Functional Connectome in Gliomas: A Mini-Review

In the central nervous system, gliomas are the most common, but complex primary tumors. Genome-based molecular and clinical studies have revealed different classifications and subtypes of gliomas. Neuroradiological approaches have non-invasively provided a macroscopic view for surgical resection and therapeutic effects. The connectome is a structural map of a physical object, the brain, which raises issues of spatial scale and definition, and it is calculated through diffusion magnetic resonance imaging (MRI) and functional MRI. In this study, we reviewed the basic principles and attributes of the structural and functional connectome, followed by the alternations of connectomes and their influences on glioma. To extend the applications of connectome, we demonstrated that a series of multi-center projects still need to be conducted to systemically investigate the connectome and the structural-functional coupling of glioma. Additionally, the brain-computer interface based on accurate connectome could provide more precise structural and functional data, which are significant for surgery and postoperative recovery. Besides, integrating the data from different sources, including connectome and other omics information, and their processing with artificial intelligence, together with validated biological and clinical findings will be significant for the development of a personalized surgical strategy.

Network analysis shows decreased ipsilesional structural connectivity in glioma patients

Gliomas that infiltrate networks and systems, such as the motor system, often lead to substantial functional impairment in multiple systems. Network-based statistics (NBS) allow to assess local network differences and graph theoretical analyses enable investigation of global and local network properties. Here, we used network measures to characterize glioma-related decreases in structural connectivity by comparing the ipsi- with the contralesional hemispheres of patients and correlated findings with neurological assessment. We found that lesion location resulted in differential impairment of both short and long connectivity patterns. Network analysis showed reduced global and local efficiency in the ipsilesional hemisphere compared to the contralesional hemispheric networks, which reflect the impairment of information transfer across different regions of a network.

Tumors and their location distinctly alter both local and global brain connectivity within the ipsilesional hemisphere of glioma patients.

Integrated analysis of the genomic and transcriptional profile of gliomas with isocitrate dehydrogenase-1 and tumor protein 53 mutations

Background: The gene mutation of isocitrate dehydrogenase-1 (IDH1) is commonly found in LGG and some GBM patients and usually carries tumor protein 53 (TP53) mutations. However, the underlying mechanisms on both mutations of glioma patients in IDH1 and TP53 are still unclear. Aim: To find the potential target markers in GBM and LGG patients with IDH1 and TP53 mutation.Method: A total of 1122 glioma patients from The Cancer Genome Atlas were enrolled and divided as wild-type (without IDH1 and TP53 mutations) or both mutant (both IDH1 and TP53 mutations). The data of clinicopathological characteristics, mRNA, mutations, and copy number alteration were analyzed. Results: IDH1 and TP53 mutations, not gene expression, affect the survival probability of GBM and LGG patients, which might be related to neuron function, immune function, tumor invasion, and metastasis. The effects of the selected gene (EMILIN3, SAA1, VSTM2A, HAMP, IFT80, and CHIC2) on glioma patients could be regulated by IDH1 and TP53 mutations and had a higher survival possibility in these patients. Conclusions: The selected genes in GBM and LGG patients with IDH1 and TP53 mutations could be a potential prognosis marker in the future.

Meta-analysis of cellular toxicity for graphene via data-mining the literature and machine learning

Since graphene is currently incorporated into various consumer products and used in a variety of applications, determining the relationships between the physicochemical properties of graphene and its toxicity is critical for conducting environmental and health risk analyses. Data from the literature suggest that exposure to graphene may result in cytotoxicity. However, existing graphene toxicity data are complex and heterogeneous, making it difficult to conduct risk assessments. Here, we conducted a meta-analysis of published data on the cytotoxicity of graphene based on 792 publications, including 986 cell viability data points, 762 half maximal inhibitory concentration (IC₅₀) data points, and 100 lactate dehydrogenase (LDH) release data points. Models to predict graphene cytotoxicity were then developed based on cell viability, IC₅₀, and LDH release as toxicity endpoints using random forests learning algorithms. The most influential attributes influencing graphene cytotoxicity were revealed to be exposure dose and detection method for cell viability, diameter and surface modification for IC₅₀, and detection method and organ source for LDH release. The meta-analysis produced three sets of key attributes for the three abovementioned toxicity endpoints that can be used in future studies of graphene toxicity. The findings indicate that rigorous data mining protocols can be combined with suitable machine learning tools to develop models with good predictive power and accuracy. The results also provide guidance for the design of safe graphene materials.

Dissociation of structural and functional connectomic coherence in glioma patients

With diffuse infiltrative glioma being increasingly recognized as a systemic brain disorder, the macroscopically apparent tumor lesion is suggested to impact on cerebral functional and structural integrity beyond the apparent lesion site. We investigated resting-state functional connectivity (FC) and diffusion-MRI-based structural connectivity (SC) (comprising edge-weight (EW) and fractional anisotropy (FA)) in isodehydrogenase mutated (IDHmut) and wildtype (IDHwt) patients and healthy controls. SC and FC were determined for whole-brain and the Default-Mode Network (DMN), mean intra- and interhemispheric SC and FC were compared across groups, and partial correlations were analyzed intra- and intermodally. With interhemispheric EW being reduced in both patient groups, IDHwt patients showed FA decreases in the ipsi- and contralesional hemisphere, whereas IDHmut patients revealed FA increases in the contralesional hemisphere. Healthy controls showed strong intramodal connectivity, each within the structural and functional connectome. Patients however showed a loss in structural and reductions in functional connectomic coherence, which appeared to be more pronounced in IDHwt glioma patients. Findings suggest a relative dissociation of structural and functional connectomic coherence in glioma patients at the time of diagnosis, with more structural connectomic aberrations being encountered in IDHwt glioma patients. Connectomic profiling may aid in phenotyping and monitoring prognostically differing tumor types.

Neurocognitive deficits in patients suffering from glioma in speech-relevant areas of the left hemisphere

OBJECTIVE

Patients with brain tumors frequently present neurocognitive deficits. Aiming at better understanding the impact of tumor localization on neurocognitive processes, we evaluated neurocognitive function prior to glioma surgery within one of four specific regions in the left speech-dominant hemisphere.

METHODS

Between 04/2011 and 12/2019, 43 patients undergoing neurocognitive evaluation prior to awake surgery for gliomas (WHO grade I: 2; II: 6; III: 23; IV: 11) in the inferior frontal gyrus (IFG; n = 20), the anterior temporal lobe (ATL; n = 6), the posterior superior temporal region/supramarginal gyrus (pST/SMG; n = 7) or the posterior middle temporal gyrus (pMTG; n = 10) of the language dominant left hemisphere were prospectively included in the study. Cognitive performances were analyzed regarding an influence of patient characteristics and tumor localization.

RESULTS

Severe impairment in at least one neurocognitive domain was found in 36 (83.7%) patients. Anxiety and depression were observed most frequently, followed by verbal memory impairments. Verbal memory was more strongly affected in patients with ATL or pST/SMG tumors compared to IFG tumors (p = 0.004 and p = 0.013, resp.). Overall, patients suffering from tumors in the ATL were most frequently and severely impaired.

CONCLUSION

Patients suffering from gliomas involving different regions within the language dominant hemisphere frequently present impairments in neurocognitive domains also other than language. Considering individual functions at risk may help in better advising patients prior to treatment and in tailoring the individual therapeutic strategy to preserve patients' quality of life.

Graph Theoretical Analysis of Brain Network Characteristics in Brain Tumor Patients: A Systematic Review

Graph theory is a branch of mathematics that allows for the characterization of complex networks, and has rapidly grown in popularity in network neuroscience in recent years. Researchers have begun to use graph theory to describe the brain networks of individuals with brain tumors to shed light on disrupted networks. This systematic review summarizes the current literature on graph theoretical analysis of magnetic resonance imaging data in the brain tumor population with particular attention paid to treatment effects and other clinical factors. Included papers were published through June 24^th, 2020. Searches were conducted on Pubmed, PsycInfo, and Web of Science using the search terms (graph theory OR graph analysis) AND (brain tumor OR brain tumour OR brain neoplasm) AND (MRI OR EEG OR MEG). Studies were eligible for inclusion if they: evaluated participants with a primary brain tumor, used graph theoretical analyses on structural or functional MRI data, MEG, or EEG, were in English, and were an empirical research study. Seventeen papers met criteria for inclusion. Results suggest alterations in network properties are often found in people with brain tumors, although the directions of differences are inconsistent and few studies reported effect sizes. The most consistent finding suggests increased network segregation. Changes are most prominent with more intense treatment, in hub regions, and with factors such as faster tumor growth. The use of graph theory to study brain tumor patients is in its infancy, though some conclusions can be drawn. Future studies should focus on treatment factors, changes over time, and correlations with functional outcomes to better identify those in need of early intervention.

New-Onset Postoperative Seizures in Patients With Diffuse Gliomas: A Risk Assessment Analysis

Background: Glioma-related epilepsy (GRE) is the most common presenting sign of patients with diffuse glioma. According to clinical experience, new-onset postoperative seizures can be observed even in patients without preoperative GRE. The current study mainly aimed to explore the risk factors of new-onset postoperative seizures in those patients. In addition, the prognostic value of new-onset postoperative seizures was also discussed.

Methods: Data of 313 patients without GRE were retrospectively reviewed. Chi-square test or Fisher's exact test were first performed to compare categorical variables between patients with new-onset postoperative seizures and those without. Subsequently, binary logistic regression analysis was conduct to further assess risk factors of new-onset postoperative seizures. Kaplan-Meier and Cox analysis were used to investigate the prognostic value of new-onset postoperative seizures for progression-free survival (PFS) and overall survival (OS).

Results: Patients with low-grade tumors (p = 0.006), isocitrate dehydrogenase 1 (IDH1) mutation (p = 0.040) or low Ki-67 expression (p = 0.005) showed a higher incidence of new-onset postoperative seizures. IDH1 mutation was identified as the only independent predictor for new-onset postoperative seizures (OR, 2.075; 95% CI, 1.051–4.098; p = 0.035). Additionally, new-onset postoperative seizure occurrence was demonstrated as an independent predicter of prolonged OS (OR, 0.574; 95% CI, 0.335–0.983; p = 0.043), while younger age, gross total resection, low-grade and IDH1 mutation were independently correlated with prolonged OS and PFS.

Conclusions: IDH1 mutation is an independent predictor for new-onset postoperative seizures in patients without preoperative GRE. Moreover, new-onset postoperative seizures can independently predict prolonged OS in those patients. The results of the current study can contribute to improving the individualized management of diffuse glioma.

Influence of Epilepsy on the Quality of Life of Patients with Brain Tumors

Epilepsy is a common consequence of brain tumors, occurring in 35 to 75% of cases. Here we evaluated the influence of epilepsy on the quality of life (QoL) of patients with malignant brain tumors (primary and metastatic) and assessed which areas of function are most affected by epilepsy and brain tumors. Sixty patients undergoing brain tumor surgery at the Neurosurgery Clinic of the 10th Military Research Hospital, Bydgoszcz, Poland (30 with epilepsy and 30 without epilepsy) were studied. Relationships between categorical variables were determined with Pearson’s chi-squared test, while continuous data were analyzed with the Mann-Whitney U-test. A p value < 0.05 was considered statistically significant. A multiple regression model was used for multivariate analysis of QoL. Patients with epilepsy more frequently reported memory disorders as a problem in their daily life. There were trends towards greater impairments in social, professional, and family life, sports and recreational activities, and daily physical activities in brain tumor patients with epilepsy rather than those without epilepsy. Higher frequency and generalized seizures significantly and adversely influenced the ability of patients to leave home and drive vehicles, but a proportion of patients with frequent, generalized seizures continued to drive regardless. Patients with generalized seizures considered the adverse effects of taking medicines as significantly disruptive. Memory disorders significantly affect the QoL of patients with epilepsy, and the importance of stopping driving must be emphasized by all healthcare professionals.

Resting-state fMRI detects alterations in whole brain connectivity related to tumor biology in glioma patients

BACKGROUND

Systemic infiltration of the brain by tumor cells is a hallmark of glioma pathogenesis which may cause disturbances in functional connectivity. We hypothesized that aggressive high-grade tumors cause more damage to functional connectivity than low-grade tumors.

METHODS

We designed an imaging tool based on resting-state functional (f)MRI to individually quantify abnormality of functional connectivity and tested it in a prospective cohort of patients with newly diagnosed glioma.

RESULTS

Thirty-four patients were analyzed (World Health Organization [WHO] grade II, n = 13; grade III, n = 6; grade IV, n = 15; mean age, 48.7 y). Connectivity abnormality could be observed not only in the lesioned brain area but also in the contralateral hemisphere with a close correlation between connectivity abnormality and aggressiveness of the tumor as indicated by WHO grade. Isocitrate dehydrogenase 1 (IDH1) mutation status was also associated with abnormal connectivity, with more alterations in IDH1 wildtype tumors independent of tumor size. Finally, deficits in neuropsychological performance were correlated with connectivity abnormality.

CONCLUSION

Here, we suggested an individually applicable resting-state fMRI marker in glioma patients. Analysis of the functional connectome using this marker revealed that abnormalities of functional connectivity could be detected not only adjacent to the visible lesion but also in distant brain tissue, even in the contralesional hemisphere. These changes were associated with tumor biology and cognitive function. The ability of our novel method to capture tumor effects in nonlesional brain suggests a potential clinical value for both individualizing and monitoring glioma therapy.

Cognitive impact of lower-grade gliomas and strategies for rehabilitation

Outcomes for patients with lower-grade gliomas (LrGGs) continue to improve with advances in molecular characterization and treatment. However, cognitive sequela from the tumor and its treatment leave a significant impact on health-related quality of life for these patients. Several factors affect each patient's cognition, such as tumor location, treatment, medication, and comorbidities. However, impairments of processing speed, attention, concentration, working memory, and executive function are common across LrGG patients. Cognitive rehabilitation strategies, well established in traumatic brain injury and stroke populations, are based on neural plasticity and functional reorganization. Adapting these strategies for implementation in patients with brain tumors is an active area of research. This article provides an overview of cognitive domains commonly impaired in LrGG patients and evidence for the use of cognitive rehabilitation strategies to address these impairments with the goal of improving health-related quality of life in this patient population.

Cognitive reserve protects language functions in patients with brain tumours

Cognitive reserve (CR) theory suggests that individual differences in general intelligence (IQ), occupational attainment or participation in leisure/recreational activities protect against cognitive decline. However the relationship between CR and cognitive functioning in patients with brain tumours has been very rarely investigated in past research. The present study systematically assesses whether CR concept can also be applied to cognitive functions of neurosurgical patients affected by brain tumours. We investigated the role of different CR proxies (education level, premorbid IQ, current IQ, working and leisure activity) in protecting language against brain tumours and surgery effects, considering interactions with demographic (sex/age), anatomical (hemisphere/lobe location of lesion) and clinical/biological variables (tumour type: High/Low Grade Glioma or Meningioma; lesion volume; lesion aggressiveness). One-hundred patients undergoing neuropsychological assessment before and immediately after surgery participated. A "Language Score" summarizing performance on all language tests was derived with Principal Component Analysis. Data were then analyzed with Multiple Regression and Classification and Regression Tree analyses to investigate possible relationships between predictors (CR proxies and clinical variables) and Language Score. We found that premorbid IQ was the best predictor of pre-operatory language integrity, above and beyond all clinical variables considered, also moderating lesion volume effects. Moreover, patients with lower pre-operatory language integrity and low-to-moderately aggressive tumours showed a mitigating effect of current IQ over surgery consequences. Results thus suggest that different CR proxies play a role in moderating cognitive decline following brain tumours and surgery.

Retrospective analysis of hemispheric structural network change as a function of location and size of glioma

Gliomas are neoplasms that arise from glial cell origin and represent the largest fraction of primary malignant brain tumours (77%). These highly infiltrative malignant cell clusters modify brain structure and function through expansion, invasion and intratumoral modification. Depending on the growth rate of the tumour, location and degree of expansion, functional reorganization may not lead to overt changes in behaviour despite significant cerebral adaptation. Studies in simulated lesion models and in patients with stroke reveal both local and distal functional disturbances, using measures of anatomical brain networks. Investigations over the last two decades have sought to use diffusion tensor imaging tractography data in the context of intracranial tumours to improve surgical planning, intraoperative functional localization, and post-operative interpretation of functional change. In this study, we used diffusion tensor imaging tractography to assess the impact of tumour location on the white matter structural network. To better understand how various lobe localized gliomas impact the topology underlying efficiency of information transfer between brain regions, we identified the major alterations in brain network connectivity patterns between the ipsilesional versus contralesional hemispheres in patients with gliomas localized to the frontal, parietal or temporal lobe. Results were indicative of altered network efficiency and the role of specific brain regions unique to different lobe localized gliomas. This work draws attention to connections and brain regions which have shared structural susceptibility in frontal, parietal and temporal lobe glioma cases. This study also provides a preliminary anatomical basis for understanding which affected white matter pathways may contribute to preoperative patient symptomology.

Tractography and the connectome in neurosurgical treatment of gliomas: the premise, the progress, and the potential

The ability of diffusion tensor MRI to detect the preferential diffusion of water in cerebral white matter tracts enables neurosurgeons to noninvasively visualize the relationship of lesions to functional neural pathways. Although viewed as a research tool in its infancy, diffusion tractography has evolved into a neurosurgical tool with applications in glioma surgery that are enhanced by evolutions in crossing fiber visualization, edema correction, and automated tract identification. In this paper the current literature supporting the use of tractography in brain tumor surgery is summarized, highlighting important clinical studies on the application of diffusion tensor imaging (DTI) for preoperative planning of glioma resection, and risk assessment to analyze postoperative outcomes. The key methods of tractography in current practice and crucial white matter fiber bundles are summarized. After a review of the physical basis of DTI and post-DTI tractography, the authors discuss the methodologies with which to adapt DT image processing for surgical planning, as well as the potential of connectomic imaging to facilitate a network approach to oncofunctional optimization in glioma surgery.

A Neurosurgeon's Guide to Cognitive Dysfunction in Adult Glioma

Cognitive decline is common among patients with low- and high-grade glioma and can significantly impact quality of life. Although cognitive outcomes have been studied after therapeutic interventions such as surgery and radiation, it is important to understand the impact of the disease process itself prior to any interventions. Neurocognitive domains of interest in this disease context include intellectual function and premorbid ability, executive function, learning and memory, attention, language function, processing speed, visuospatial function, motor function, and emotional function. Here, we review oncologic factors associated with more neurocognitive impairment, key neurocognitive tasks relevant to glioma patient assessment, as well as the relevance of the human neural connectome in understanding cognitive dysfunction in glioma patients. A contextual understanding of glioma-functional network disruption and its impact on cognition is critical in the surgical management of eloquent area tumors.

Connectivity of the Cerebello-Thalamo-Cortical Pathway in Survivors of Childhood Leukemia Treated With Chemotherapy Only

IMPORTANCE

Treatment with contemporary chemotherapy-only protocols is associated with risk for neurocognitive impairment among survivors of childhood acute lymphoblastic leukemia (ALL).

OBJECTIVE

To determine whether concurrent use of methotrexate and glucocorticoids is associated with interference with the antioxidant system of the brain and damage and disruption of glucocorticoid-sensitive regions of the cerebello-thalamo-cortical network.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted from December 2016 to July 2019 in a single pediatric cancer tertiary care center. Participants included survivors of childhood ALL who were more than 5 years from cancer diagnosis, age 8 years or older, and treated on an institutional chemotherapy-only protocol. Age-matched community members were recruited as a control group. Data were analyzed from August 2017 to August 2020.

EXPOSURE

ALL treatment using chemotherapy-only protocols.

MAIN OUTCOMES AND MEASURES

This study compared brain volumes between survivors and individuals in a community control group and examined associations among survivors of methotrexate and dexamethasone exposure with neurocognitive outcomes. Functional and effective connectivity measures were compared between survivors with and without cognitive impairment. The Rey-Osterrieth complex figure test, a neurocognitive evaluation in which individuals are asked to copy a figure and then draw the figure from memory, was scored according to published guidelines and transformed into age-adjusted z scores based on nationally representative reference data and used to measure organization and planning deficits. β values for neurocognitive tests represented the amount of change in cerebellar volume or chemotherapy exposure associated with 1 SD change in neurocognitive outcome by z score (mm3/1 SD in z score for cerebellum, mm3/[g×hr/L] for dexamethasone and methotrexate AUC, and mm3/intrathecal count for total intrathecal count).

RESULTS

Among 302 eligible individuals, 218 (72%) participated in the study and 176 (58%) had usable magnetic resonance imaging (MRI) results. Among these, 89 (51%) were female participants and the mean (range) age was 6.8 (1-18) years at diagnosis and 14.5 (8-27) years at evaluation. Of 100 community individuals recruited as the control group, 82 had usable MRI results; among these, 35 (43%) were female individuals and the mean (range) age was 13.8 (8-26) years at evaluation. There was no significant difference in total brain volume between survivors and individuals in the control group. Survivors of both sexes showed decreased mean (SD) cerebellar volumes compared with the control population (female: 70 568 [6465] mm3 vs 75 134 [6780] mm3; P < .001; male: 77 335 [6210] mm3 vs 79 020 [7420] mm3; P < .001). In female survivors, decreased cerebellar volume was associated with worse performance in Rey-Osterrieth complex figure test (left cerebellum: β = 55.54; SE = 25.55; P = .03; right cerebellum: β = 52.57; SE = 25.50; P = .04) and poorer dominant-hand motor processing speed (ie, grooved pegboard performance) (left cerebellum: β = 82.71; SE = 31.04; P = .009; right cerebellum: β = 91.06; SE = 30.72; P = .004). In female survivors, increased number of intrathecal treatments (ie, number of separate injections) was also associated with Worse Rey-Osterrieth test performance (β = -0.154; SE = 0.063; P = .02), as was increased dexamethasone exposure (β = -0.0014; SE = 0.0005; P = .01). Executive dysfunction was correlated with increased global efficiency between smaller brain regions (Pearson r = -0.24; P = .01) compared with individuals without dysfunction. Anatomical connectivity showed differences between impaired and nonimpaired survivors. Analysis of variance of effective-connectivity weights identified a significant interaction association (F = 3.99; P = .02) among the direction and strength of connectivity between the cerebellum and DLPFC, female sex, and executive dysfunction. Finally, no effective connectivity was found between the precuneus and DLPFC in female survivors with executive dysfunction.

CONCLUSIONS AND RELEVANCE

These findings suggest that dexamethasone exposure was associated with smaller cerebello-thalamo-cortical regions in survivors of ALL and that disruption of effective connectivity was associated with impairment of executive function in female survivors.

Isocitrate Dehydrogenase, Patient-Reported Outcomes, and Cognitive Functioning of Glioma Patients: a Systematic Review

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutation status has important prognostic implications in glioma patients, with IDH wild-type (IDH-WT) gliomas being associated with worse prognosis and shorter survival when compared with IDH mutant (IDH-mut) gliomas. Optimization of quality of life is a priority in the management of glioma patients. The goal of this systematic review was to identify studies that explored the association of IDH mutation status with patient-reported outcomes (PROs) and cognitive functioning of glioma patients.

RECENT FINDINGS

Studies that evaluated the association of IDH mutation status with PROs and/or cognitive functioning of glioma patients were identified from the Pubmed/MEDLINE, Clarivate analytics, and Google Scholar databases. Eight studies (7 journal articles and 2 conference abstracts) with a total of 658 low-grade glioma and high-grade glioma patients investigated the association of cognitive functioning and/or QoL with IDH status. IDH-WT status was associated with greater cognitive impairment relative to IDH-Mut status in three studies, while one study did not find the association between IDH status and perioperative cognitive functioning. One study reported worse postoperative cognitive functioning patients with IDH-WT vs. IDH-mut gliomas. In one study, IDH-WT status was linked to greater impairment on physical and communication functioning after surgery. IDH-WT gliomas are associated with greater cognitive burden than IDH-Mut tumors. The association of IDH status with QoL remains less clear. Assessment of IDH status should be considered when evaluating QoL and cognitive complaints of glioma patients. Further studies linking glioma molecular phenotypes with PROs and cognitive functioning are encouraged.

Functional connectome biotypes of chemotherapy-related cognitive impairment

PURPOSE

Cancer-related cognitive impairment (CRCI) is a common neurotoxicity among patients with breast and other cancers. Neuroimaging studies have demonstrated measurable biomarkers of CRCI but have largely neglected the potential heterogeneity of the syndrome.

METHODS

We used retrospective functional MRI data from 80 chemotherapy-treated breast cancer survivors to examine neurophysiologic subtypes or "biotypes" of CRCI. The breast cancer group consisted of training (N = 57) and validation (N = 23) samples.

RESULTS

An unsupervised clustering approach using connectomes from the training sample identified three distinct biotypes. Cognitive performance (p < 0.05, corrected) and regional connectome organization (p < 0.001, corrected) differed significantly between the biotypes and also from 103 healthy female controls. We then built a random forest classifier using connectome features to distinguish between the biotypes (accuracy = 91%) and applied this to the validation sample to predict biotype assignment. Cognitive performance (p < 0.05, corrected) and regional connectome organization (p < 0.005, corrected) differed significantly between the predicted biotypes and healthy controls. Biotypes were also characterized by divergent clinical and demographic factors as well as patient reported outcomes.

CONCLUSIONS

Neurophysiologic biotypes may help characterize the heterogeneity associated with CRCI in a data-driven manner based on neuroimaging biomarkers.

IMPLICATIONS FOR CANCER SURVIVORS

Our novel findings provide a foundation for detecting potential risk and resilience factors that warrant further study. With further investigation, biotypes might be used to personalize assessments of and interventions for CRCI.

Asymmetric tumor-related alterations of network-specific intrinsic functional connectivity in glioma patients

Resting-state functional MRI (rs-fMRI) allows mapping temporally coherent brain networks, and intra- and inter-network alterations have been described in different diseases. This prospective study investigated hemispheric resting-state functional connectivity (RSFC) differences in the default-mode network (DMN) and fronto-parietal network (FPN) between patients with left- and right-hemispheric gliomas (LH PAT, RH PAT), addressing asymmetry effects the tumor might have on network-specific intrinsic functional connectivity under consideration of the prognostically relevant isocitrate-dehydrogenase (IDH) mutation status. Twenty-seven patients (16 LH PAT, 12 IDH-wildtype) and 27 healthy controls underwent anatomical and rs-fMRI as well as neuropsychological assessment. Independent component analyses were performed to identify the DMN and FPN. Hemispheric DMN- and FPN-RSFC were computed, compared across groups, and correlated with cognitive performance. Patient groups did not differ in tumor volume, grade or location. RH PAT showed higher contra-tumoral DMN-RSFC than controls and LH PAT. With regard to the FPN, contra-tumoral RSFC was increased in both patient groups as compared to controls. Higher contra-tumoral RSFC was associated with worse cognitive performance in patients, which, however, seemed to apply mainly to IDH-wildtype patients. The benefit of RSFC alterations for cognitive performance varied depending on the affected hemisphere, cognitive demand, and seemed to be altered by IDH-mutation status. At the time of study initiation, a clinical trial registration was not mandatory at our faculty, but it can be applied for if requested.

Treatment of cognitive deficits in brain tumour patients: current status and future directions

Increased life expectancy in brain tumour patients had led to the need for strategies that preserve and improve cognitive functioning, as many patients suffer from cognitive deficits. The tumour itself, as well as antitumor treatment including surgery, radiotherapy and chemotherapy, supportive treatment and individual patient factors are associated with cognitive problems. Here, we review the recent literature on approaches that preserve and improve cognitive functioning, including pharmacological agents and rehabilitation programs.

Biomarkers panels can predict fatigue, depression and pain in persons living with HIV: A pilot study

BACKGROUND

Persons living with HIV experience high symptom burden that can negatively impact medication adherence, work productivity, and quality of life. Symptoms are highly subjective, which can lead to under- or improper treatment. The purpose of this exploratory study was to examine relationships between circulating biomarkers representative of inflammatory, coagulation, and vascular function pathways and prevalent HIV symptoms.

SETTING AND SAMPLE

Adults >18 years who were diagnosed with HIV and spoke English for this cross-sectional study were recruited from community clinics and organizations.

METHODS

Symptom burden was measured with the HIV Symptom Index; depression with the Patient Health Questionnaire. Human multiplex kits were used to determine serum concentrations of select biomarkers representing inflammatory, coagulation, and vascular function pathways. The biomarkers were included as features in machine learning models to determine which biomarkers predicted the most prevalent HIV symptoms (fatigue and muscle/joint pain) and the symptom of depression.

RESULTS

Participants (N = 32) were representative of the local population of people with HIV, being mostly Black (54.4%) and male (60.6%). Depression was predicted by age, gender, glucose, hemoglobin A1c, and inflammation. Muscle/joint pain was predicted by adiponectin, C-reactive protein, and serum amyloid A (SAA). Fatigue was predicted by adiponectin, SAA, and soluble interleukin-1 receptor type II (sIL-1RII).

CONCLUSION

Biomarker clusters can be a tool to monitor symptoms. Adding an objective measure to subjective patient experiences could improve management and monitoring of symptoms. Defining a biomarker cluster for the objective assessment of HIV symptoms warrants further investigation; however, the presence of comorbid conditions needs to be controlled.

Risk Factors for Cognitive Impairment in High-Grade Glioma Patients Treated with Postoperative Radiochemotherapy

Purpose

Fractionated radiotherapy as well as concomitant and adjuvant chemotherapy such as temozolomide for postoperative high-grade glioma (HGG) patients improves progression-free survival and overall survival. Multiple factors such as chemotherapy, radiotherapy, tumor grade, residual tumor volume, and genetic modifications might play a role in the formation of cognitive impairment. The risk factors of cognitive impairment in postoperative patients with HGG receiving radiotherapy and chemotherapy remains a concern in this population. The purpose of this study was to identify risk factors for cognitive impairment in patients of postoperative HGG.

Materials and Methods

A total of 229 patients with HGG who underwent surgery were analyzed. Cognitive impairment was defined as a decrease of Cognitive Assessment Montreal (MoCA)’s score in at least two cognitive domains or any MoCA’s score of less than 26 points at the time of study compared with baseline level. Multiple potential risk factors including methylated status of the O⁶-methylguanine-DNA methyltransferase (MGMT) promoter, glioma World Health Organization (WHO) grade, residual tumor volume, education, and sex were analyzed. Cox univariate and multivariate regression analysis was used to detect the significant risk factors for cognitive impairment.

Results

At the end of follow-up among the 229 patients, 147 patients (67%) developed cognitive impairment. 82 patients (36%) remained in normal cognitive condition. In multivariate analysis, unmethylated MGMT promoter (hazard ratio [HR], 1.679; 95% confidence interval [CI], 1.212 to 2.326; p=0.002), glioblastoma (HR, 1.550; 95% CI, 1.117 to 2.149; p=0.009), and residual tumor volume > 5.58 cm³ (HR, 1.454; 95% CI, 1.047 to 2.020; p=0.026) were independent risk factors for cognitive impairment.

Conclusion

Methylated status of the MGMT promoter, glioma WHO grade, and residual tumor volume might be risk factors for the cognitive impairment in postoperative patients with HGG.

Pre-surgical connectome features predict IDH status in diffuse gliomas

BACKGROUND

Gliomas are the most common type of malignant brain tumor. Clinical outcomes depend on many factors including tumor molecular characteristics. Mutation of the isocitrate dehydrogenase (IDH) gene confers significant benefits in terms of survival and quality of life. Preoperative determination of IDH genotype can facilitate surgical planning, allow for novel clinical trial designs, and assist clinical counseling surrounding the individual patient's disease.

METHODS

In this study, we aimed to evaluate a novel approach for non-invasively predicting IDH status from conventional MRI via connectomics, a whole-brain network-based technique. We retrospectively extracted 93 connectome features from the preoperative, T1-weighted MRI data of 234 adult patients (148 IDH mutated) and evaluated the performance of four common machine learning models to predict IDH genotype.

RESULTS

Area under the curve (AUC) of the receiver operator characteristic were 0.76 to 0.94 with random forest (RF) showing significantly higher performance (p < 0.01) than other algorithms. Feature selection schemes and the addition of age and tumor location did not change RF performance.

CONCLUSIONS

Our findings suggest that connectomics is a feasible approach for preoperatively predicting IDH genotype in patients with gliomas. Our results support prior evidence that RF is an ideal machine learning method for this area of research. Additionally, connectomics provides unique insights regarding potential mechanisms of tumor genotype on large-scale brain network organization.

Neurocognitive Function in Adult Cancer Patients

Impaired neurocognitive function is an increasingly recognized morbidity in patients who have cancer. Cancer treatments, psychosocial stressors, and the malignancy itself can alter brain function. The mechanisms by which this occurs are under active investigation. Although there is a growing appreciation of its prevalence and causes, there remain limited therapeutic options for the treatment of neurocognitive dysfunction in this population. A persistent scientific and clinical effort to understand its mechanisms and impact is critical to the care of oncology patients.

Cognitive functioning in glioma patients is related to functional connectivity measures of the non-tumoural hemisphere

Previous studies have shown that cognitive functioning in patients with brain tumour is associated with the functional network characteristics of specific resting‐state networks or with whole‐brain network characteristics. These studies, however, did not acknowledge the functional contribution of areas in the contralesional, non‐tumoural hemisphere, even though these healthy remote areas likely play a critical role in compensating for the loss of function in damaged tissue. In the current study, we examined whether there is an association between cognitive performance and functional network features of the contralesional hemisphere of patients with glioma. We found that local efficiency of the contralesional hemisphere was associated with performance on the reaction time domain, whereas contralesional assortativity was associated with complex attention and cognitive flexibility scores. Our results suggest that a less segregated organization of the contralesional hemisphere is associated with better reaction time scores, whereas a better spread of information over the contralesional hemisphere through mutually interconnected contralesional hubs is associated with better cognitive flexibility and better complex attention scores. These findings urge researchers to recognize the functional contribution of remote, undamaged regions and to focus more on the graph metrics of the contralesional hemisphere in the search for predictors of cognitive functioning in patients with brain tumour.

Monitoring of Neurocognitive Function in the Care of Patients with Brain Tumors

PURPOSE OF REVIEW

A detailed characterization of the nature of neurocognitive impairment in patients with brain tumors is provided, as well as considerations for clinical practice regarding neuropsychological assessment throughout the disease course.

RECENT FINDINGS

Neurocognitive impairment is common in patients with brain tumors and may result from the tumor itself, as a consequence of treatment, including surgery, chemotherapy, and radiation, or in association with supportive care medications (e.g., anticonvulsant and pain medications). Serial surveillance of neurocognitive functioning in this population can facilitate medical decision-making and inform recommendations to improve patient daily functioning and quality of life. Neuropsychological assessment is increasingly recognized as a critical component of the multidisciplinary care of patients with brain tumors and has already had practice-changing effects. Further understanding of genetic risk factors for neurocognitive decline along with the development of novel assessment and intervention strategies may further enhance functioning and general well-being in this patient population.

Understanding cognitive functioning in glioma patients: The relevance of IDH-mutation status and functional connectivity

INTRODUCTION

Cognitive deficits occur frequently in diffuse glioma patients, but are limitedly understood. An important marker for survival in these patients is isocitrate dehydrogenase (IDH) mutation (IDH-mut). Patients with IDH-mut glioma have a better prognosis but more often suffer from epilepsy than patients with IDH-wildtype (IDH-wt) glioma, who are generally older and more often have cognitive deficits. We investigated whether global brain functional connectivity differs between patients with IDH-mut and IDH-wt glioma, and whether this measure reflects variations in cognitive functioning in these subpopulations beyond the associated differences in age and presence of epilepsy.

METHODS

We recorded magnetoencephalography and tested cognitive functioning in 54 diffuse glioma patients (31 IDH-mut, 23 IDH-wt). Global functional connectivity between 78 atlas regions spanning the entire cortex was calculated in two frequency bands (theta and alpha). Group differences in global functional connectivity were tested, as was their association with cognitive functioning, controlling for age, education, and presence of epilepsy.

RESULTS

Patients with IDH-wt glioma had lower functional connectivity in the alpha band than patients with IDH-mut glioma (p = 0.040, corrected for age and presence of epilepsy). Lower alpha band functional connectivity was associated with poorer cognitive performance (p < 0.034), corrected for age, education, and presence of epilepsy.

CONCLUSION

Global functional connectivity is lower in patients with IDH-wt diffuse glioma compared to patients with IDH-mut diffuse glioma. Moreover, having lower functional alpha connectivity relates to poorer cognitive performance in patients with diffuse glioma, regardless of age, education, and presence of epilepsy.

Depressive symptoms and executive function in relation to survival in patients with glioblastoma

INTRODUCTION

Depression and neurocognitive function, particularly executive functioning (EF), have been associated with overall survival (OS) in patients with glioblastoma (GBM). However, the combined effect of depressive symptoms and impaired EF upon OS has not been reported.

METHODS

Patients with GBM (N = 102) completed neuropsychological assessment postoperatively, including the Beck Depression Inventory-Second Edition (BDI-II) and the Trail Making Test Part B (TMTB). Median splits were used to determine cut-points denoting elevated depressive symptoms on the BDI-II and impaired EF on TMTB. Patients were stratified into four groups: low depressive symptoms/low EF impairment (- Dep/- Imp; N = 23), high depressive symptoms/low EF impairment (+ Dep/- Imp; N = 28), low depressive symptoms/high EF impairment (- Dep/+Imp; N = 28), and high depressive symptoms/high EF impairment (+ Dep/+Imp; N = 23). The Kaplan-Meier method, log-rank test, and Cox regression were used to examine differences in survival between groups.

RESULTS

Relative to - Dep/- Imp patients (median OS = 22.8 months), median OS in all other patient groups was shorter (+ Dep/- Imp OS = 16.6; - Dep/+Imp OS = 14.8; +Dep/+Imp OS = 10.8; all p < .05). With the exception of KPS and age, groups did not differ in distribution of clinical and demographic characteristics. Neither KPS nor age modified the independent effect of BDI-II and TMTB on OS in Cox regression models.

CONCLUSIONS

The presence of depressive symptoms and impaired EF are independently associated with shorter OS in patients with GBM. These results suggest that routine neuropsychological assessment of mood and cognition may help refine prognosis and facilitate initiation of psychological and cognitive interventions, which can improve patient quality of life, and warrants further investigation.

Neuropsychological Practice in the Oncology Setting

Oncology has experienced positive shifts in survival curves for many cancers largely due to the development of earlier diagnostics and better therapeutics. This has increased the visibility and need for survivorship services, including clinical neuropsychology. Patients with cancer frequently experience cognitive dysfunction related to the presence of cancer itself and treatment neurotoxicity. These cognitive difficulties can profoundly impact patient functioning and autonomy with accompanying declines in quality of life. Clinical neuropsychologists are uniquely positioned to evaluate the cognitive and affective sequelae of cancer and treatment and provide interventions and recommendations that can benefit well-being and potentially alter the disease course. Despite increasing recognition of the importance of neuropsychological issues to cancer survivorship, many neuropsychologists have limited training and guidance regarding navigating and implementing services within the oncology setting. This article provides the basic rationale for neuropsychological practice and research activities in oncology, as well as the experience of the Section of Neuropsychology at The University of Texas MD Anderson Cancer Center.

Brain Network Connectivity and Executive Function in Long-Term Survivors of Childhood Acute Lymphoblastic Leukemia

Chemotherapeutic agents used to treat acute lymphoblastic leukemia (ALL), the most common cancer affecting young children, have been associated with long-term cognitive impairments that reduce quality of life. Executive dysfunction is one of the most consistently observed deficits and can have substantial and pervasive effects on academic success, occupational achievement, psychosocial function, and psychiatric status. We examined the neural mechanisms of executive dysfunction by measuring structural and functional connectomes in 161 long-term survivors of pediatric ALL, age 8-21 years, who were treated on a single contemporary chemotherapy-only protocol for standard/high- or low-risk disease. Lower global efficiency, a measure of information exchange and network integration, of both structural and functional connectomes was found in survivors with executive dysfunction compared with those without dysfunction (p < 0.046). Patients with standard/high- versus low-risk disease and those who received greater number of intrathecal treatments containing methotrexate had the lowest network efficiencies. Patients with executive dysfunction also showed hyperconnectivity in sensorimotor, visual, and auditory-processing regions (p = 0.037) and poor separation between sensorimotor, executive/attention, salience, and default mode networks (p < 0.0001). Connectome disruption was consistent with a pattern of delayed neurodevelopment that may be associated with reduced resilience, adaptability, and flexibility of the brain network. These findings highlight the need for interventions that will prevent or manage cognitive impairment in survivors of pediatric acute lymphoblastic leukemia.