Overall survival in patients with malignant glioma may be significantly longer with tumors located in deep grey matter

The apparent diffusion coefficient can serve as a predictor of survival in patients with gliomas

BACKGROUND AND PURPOSE

Magnetic resonance imaging is indispensable for the preoperative diagnosis of glioma. This study aimed to investigate the role of the apparent diffusion coefficient values as predictors of survival in patients with gliomas.

METHODS AND MATERIALS

A retrospective analysis was conducted on 101 patients with gliomas who underwent surgery between 2015 and 2020. Diffusion-weighted MRI was performed before the surgery. The regions of interest were categorized into parenchymal area, non-enhancing peritumoral area, and necrotic or cystic area. All the patients were divided into three subgroups: the parenchyma group, the non-enhancing peritumoral signal abnormality group, and the necrosis or cyst group. Univariate and multivariate analyses were performed using COX regression.

RESULTS

In the parenchymal group, Ki67, P53, IDH, and the high or low ADC values were identified as independent prognosticators for disease-free survival, while Ki67, IDH, and the high or low ADC values for overall survival. In the non-enhancing peritumoral signal abnormality group, Ki67, P53, IDH, and the ADC parenchymal area/ADC non-enhancing peritumoral area ratio were identified as independent prognostic factors for disease-free survival, while Ki67, IDH, and the ADC parenchymal area/ADC non-enhancing peritumoral area ratio for overall survival. In the necrosis or cyst group, Ki67 was significantly associated with disease-free survival, while Ki67 and the ADC value of the necrotic or cystic area for overall survival.

CONCLUSIONS

The ADC values, including the ADC value in the parenchymal area, the ADC parenchymal area/ADC non-enhancing peritumoral area ratio, and the ADC value in the necrotic or cystic area, can serve as an efficient and potential index for predicting the survival of patients with glioma.

The effect of midline shift on survival time in dogs with structural brain disease diagnosed on MRI

The effect of midline shift identified on brain MRI on survival time in dogs with structural brain disease is relatively unknown. This retrospective single-centered cohort study reviewed medical and imaging data of 77 dogs with structural brain lesions evident on MRI. Images were reviewed for the presence of midline shift, brain edema, foramen magnum herniation, and ventriculomegaly. Kaplan-Meier method and Cox regression analysis were undertaken to compare survival between dogs with and without midline shift. Midline shift was present in 40 of 77 (52%) dogs and absent in 37 of 77 (48%). Univariate analysis revealed that dogs with midline shift had a median survival time of 34.5 days (95% CI, 4-108 days) compared with 241 days (95% CI, 133,- days) in dogs without midline shift (hazard ratio = 2.67, 95% CI, 1.5-4.49). Multivariate Cox regression analysis revealed a hazard ratio of 3.6 (95% CI, 1.7-7.6; P-value < .001) for dogs with midline shift. Shorter median survival times remained significant in all groups after segregation based on etiological diagnosis. The significantly shorter survival times observed herein for dogs with midline shifts, regardless of etiologic cause, provide further evidence that midline shift holds value as a negative prognostic factor in diagnostic imaging.

Conventional and Advanced Magnetic Resonance Imaging Assessment of Non-Enhancing Peritumoral Area in Brain Tumor

The non-enhancing peritumoral area (NEPA) is defined as the hyperintense region in T2-weighted and fluid-attenuated inversion recovery (FLAIR) images surrounding a brain tumor. The NEPA corresponds to different pathological processes, including vasogenic edema and infiltrative edema. The analysis of the NEPA with conventional and advanced magnetic resonance imaging (MRI) was proposed in the differential diagnosis of solid brain tumors, showing higher accuracy than MRI evaluation of the enhancing part of the tumor. In particular, MRI assessment of the NEPA was demonstrated to be a promising tool for distinguishing high-grade gliomas from primary lymphoma and brain metastases. Additionally, the MRI characteristics of the NEPA were found to correlate with prognosis and treatment response. The purpose of this narrative review was to describe MRI features of the NEPA obtained with conventional and advanced MRI techniques to better understand their potential in identifying the different characteristics of high-grade gliomas, primary lymphoma and brain metastases and in predicting clinical outcome and response to surgery and chemo-irradiation. Diffusion and perfusion techniques, such as diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), dynamic susceptibility contrast-enhanced (DSC) perfusion imaging, dynamic contrast-enhanced (DCE) perfusion imaging, arterial spin labeling (ASL), spectroscopy and amide proton transfer (APT), were the advanced MRI procedures we reviewed.

The Prognostic Role of Peritumoral Edema in Patients with Newly Diagnosed Glioblastoma: A Retrospective Analysis

OBJECTIVE

Previous studies on glioblastomas (GBMs) have not reached a consensus on peritumoral edema (PTE)'s influence on survival. This study evaluated the PTE index's prognostic role in newly diagnosed GBMs using a well-designed method.

METHODS

Selected patients were reviewed after a rigorous screening process. Their general information was obtained from electronic medical records. The imaging metrics (MTD, TTM, TTE) representing tumor diameter, laterality, and PTE extent were obtained by manual measurement in Syngo FastView software. The PTE index was a ratio of TTE to MTD. Multiple variables were evaluated using analysis of variance and Cox regression model.

RESULTS

Of 143 patients, 62 were included in this study. MGMT promoter methylation and tumor laterality were both independent prognostic factors (p = 0.020, 0.042; HR = 0.272, 2.630). The lateral tumors' index was higher than that of the medial tumors (57.7% vs. 42.6%, p = 0.027). Low-index tumors were located in relatively medial positions compared with high-index tumors (TTM, 4.9 vs. 12.8, p = 0.032). This finding indicated that the PTE index tended to increase with tumor laterality. Moreover, the patients with low-index tumors had a significant survival disadvantage in the univariate analysis but not in the multivariate analysis (p = 0.023, 0.220). However, further analysis found that the combination of tumor laterality and PTE statistically stratified the survival outcome. The patients with lateral high-index tumors survived significantly longer (p = 0.022, HR = 1.927).

CONCLUSIONS

In contrast with the previous studies, this study recommends combining PTE and tumor laterality for survival stratification in newly diagnosed GBMs.

Assessment of Pre-operative Measurements of Tumor Size by MRI Methods as Survival Predictors in Wild Type IDH Glioblastoma

Objective: We evaluate the performance of three MRI methods to determine non-invasively tumor size, as overall survival (OS) and Progression Free Survival (PFS) predictors, in a cohort of wild type, IDH negative, glioblastoma patients. Investigated protocols included bidimensional (2D) diameter measurements, and three-dimensional (3D) estimations by the ellipsoid or semi-automatic segmentation methods.

Methods: We investigated OS in a cohort of 44 patients diagnosed with wild type IDH glioblastoma (58.2 ± 11.4 years, 1.9/1 male/female) treated with neurosurgical resection followed by adjuvant chemo and radiotherapy. Pre-operative MRI images were evaluated to determine tumor mass area and volume, gadolinium enhancement volume, necrosis volume, and FLAIR-T₂ hyper-intensity area and volume. We implemented then multivariate Cox statistical analysis to select optimal predictors for OS and PFS.

Results: Median OS was 16 months (1–42 months), ranging from 9 ± 2.4 months in patients over 65 years, to 18 ± 1.6 months in younger ones. Patients with tumors carrying O⁶-methylguanin-DNA-methyltransferase (MGMT) methylation survived 30 ± 5.2 vs. 13 ± 2.5 months in non-methylated. Our study evidenced high and positive correlations among the results of the three methods to determine tumor size. FLAIR-T₂ hyper-intensity areas (2D) and volumes (3D) were also similar as determined by the three methods. Cox proportional hazards analysis with the 2D and 3D methods indicated that OS was associated to age ≥ 65 years (HR 2.70, 2.94, and 3.16), MGMT methylation (HR 2.98, 3.07, and 2.90), and FLAIR-T₂ ≥ 2,000 mm² or ≥60 cm³ (HR 4.16, 3.93, and 3.72), respectively. Other variables including necrosis, tumor mass, necrosis/tumor ratio, and FLAIR/tumor ratio were not significantly correlated with OS.

Conclusion: Our results reveal a high correlation among measurements of tumor size performed with the three methods. Pre-operative FLAIR-T₂ hyperintensity area and volumes provided, independently of the measurement method, the optimal neuroimaging features predicting OS in primary glioblastoma patients, followed by age ≥ 65 years and MGMT methylation.

Prognostic Value of Conventional Magnetic Resonance Imaging for Adult Patients with Brain Tumors

PURPOSE

Magnetic resonance imaging (MRI) is the pivotal diagnostic step in patients with brain tumors, and is performed before histological diagnosis is available. We hypothesized that conventional MRI is as accurate as tumor histology in differentiating malignant from benign clinical course.

METHODS

Two neuroradiologists blinded to any clinical information evaluated the first diagnostic MRI of 244 brain tumor patients before any treatment, using a self-developed standardized list of image criteria and prospectively determined world health organization (WHO) tumor grade and tumor entity. All patients were examined with at least T1- and T2-weighted spin echo sequences before and after contrast injection on 1 and 1.5-T MRI scanners. Following the patients prospectively for 8-13 years after diagnosis, we were able to use nonsurvival at 5 years as a criterion for malignity and reference for the prognostic accuracy of both MRI and tumor tissue histology.

RESULTS

The accuracy for predicting nonsurvival at 5 years was 91% (95% confidence interval (CI): 87-94%) for MRI and 92% (95% CI: 88-95%) for histology. The Kaplan-Meier survival curves of patients with benign and malignant brain tumors as diagnosed by MRI or histology differed significantly (p < 0.001). Histology confirmed benignity or malignity in 201 patients (82%, 95% CI: 77-87%). Sources of misdiagnosis were metastases diagnosed as astrocytoma WHO IV, atypical meningiomas, and low-grade astrocytoma with malignant transformation.

CONCLUSION

MRI appears as accurate as histology in predicting survival at 5 years after diagnosis. Histological diagnosis may be more specific, however, and is needed to assess the tumor's specific biology.

Pre-operative peritumoral edema and survival rate in glioblastoma multiforme

The aim of this systematic review was to examine the relationship between pre-operative peritumoral edema and survival in patients with glioblastoma multiforme (GBM). We searched for studies involving patients with GBM who underwent pre-operative imaging (magnetic resonance imaging and/or computed tomography) in which the peritumoral edema was assessed as a prognostic factor for survival. 7 retrospective studies met the eligibility criteria and were included in the study. 2 studies found that pre-operative peritumoral edema was an independent prognostic factor for decreased survival. 1 study found that survival was dependent on the severity of the peritumoral edema (minimal and severe: increased survival; moderate: decreased survival). 2 studies found that pre-operative peritumoral edema was a predictor of decreased survival based on univariate but not multivariate analysis. 1 study found that there was no relationship between pre-operative peritumoral edema and survival, while the remaining study found that patients with peritumoral edema had decreased survival compared with patients without peritumoral edema. There was considerable heterogeneity between the studies regarding the patient characteristics. The results of our systematic review are inconclusive; the available evidence does not definitely support or rule out an association between pre-operative peritumoral edema and survival. Hence, further, well-designed, prospective studies are clearly needed.

Interstitial flow in a 3D microenvironment increases glioma invasion by a CXCR4-dependent mechanism

Brain tumor invasion leads to recurrence and resistance to treatment. Glioma cells invade in distinct patterns, possibly determined by microenvironmental cues including chemokines, structural heterogeneity, and fluid flow. We hypothesized that flow originating from pressure differentials between the brain and tumor is active in glioma invasion. Using in vitro models, we show that interstitial flow promotes cell invasion in multiple glioma cell lines. Flow effects were CXCR4-dependent, because they were abrogated by CXCR4 inhibition. Furthermore, CXCR4 was activated in response to flow, which could be responsible for enhanced cell motility. Flow was seen to enhance cell polarization in the flow direction, and this flow-induced polarization could be blocked by CXCR4 inhibition or CXCL12 oversaturation in the matrix. Furthermore, using live imaging techniques in a three-dimensional flow chamber, there were more cells migrating and more cells migrating in the direction of flow. This study shows that interstitial flow is an active regulator of glioma invasion. The new mechanisms of glioma invasion that we identify here-namely, interstitial flow-enhanced motility, activation of CXCR4, and CXCL12-driven autologous chemotaxis-are significant in therapy to prevent or treat brain cancer invasion. Current treatment strategies can lead to edema and altered flow in the brain, and one popular experimental treatment in clinical trials, convection enhanced delivery, involves enhancement of flow in and around the tumor. A better understanding of how interstitial flow at the tumor margin can alter chemokine distributions, cell motility, and directed invasion offers a better understanding of treatment failure. .

Conditional survival of high-grade glioma in Los Angeles County during the year 1990-2000

Survival probabilities for high-grade glioma are estimated at the time of diagnosis and provide limited information following treatment. This study determined dynamic indices to predict post-diagnosis survival for high-grade glioma patients. Survival information for 2,743 patients with high-grade glioma, diagnosed in Los Angeles County during the years 1990-2000, were used to estimate conditional survival probabilities with 95 % confidence intervals, for patients still alive at 1, 2, 3, 4, or 5 years after diagnosis. The conditional probabilities of surviving one additional year increase as the post-diagnosis survival time increases (from 43 ± 2 % conditional on surviving 1 year after diagnosis to 91 ± 2 % conditional on surviving 5 years after diagnosis). Patients diagnosed with WHO grade III gliomas have higher conditional survival probabilities than those diagnosed WHO grade IV gliomas. However, as the years after diagnosis increase, the differences in the conditional probabilities between the two groups are attenuated. At the time of diagnosis, age and tumor histology (WHO grade), tumor site, primary treatment, time of treatment start after diagnosis, as well as whether the patient was treated at a teaching hospital were significantly associated with overall survival. By 4 years post-diagnosis however, with the exception of age, variables associated with survival at baseline were no longer significantly associated with survival. Conditional survival probabilities provide clinically relevant information for understanding the prognosis for patients with high-grade gliomas.

Survival analysis of patients with high-grade gliomas based on data mining of imaging variables

BACKGROUND AND PURPOSE

The prediction of prognosis in HGGs is poor in the majority of patients. Our aim was to test whether multivariate prediction models constructed by machine-learning methods provide a more accurate predictor of prognosis in HGGs than histopathologic classification. The prediction of survival was based on DTI and rCBV measurements as an adjunct to conventional imaging.

MATERIALS AND METHODS

The relationship of survival to 55 variables, including clinical parameters (age, sex), categoric or continuous tumor descriptors (eg, tumor location, extent of resection, multifocality, edema), and imaging characteristics in ROIs, was analyzed in a multivariate fashion by using data-mining techniques. A variable selection method was applied to identify the overall most important variables. The analysis was performed on 74 HGGs (18 anaplastic gliomas WHO grades III/IV and 56 GBMs or gliosarcomas WHO grades IV/IV).

RESULTS

Five variables were identified as the most significant, including the extent of resection, mass effect, volume of enhancing tumor, maximum B0 intensity, and mean trace intensity in the nonenhancing/edematous region. These variables were used to construct a prediction model based on a J48 classification tree. The average classification accuracy, assessed by cross-validation, was 85.1%. Kaplan-Meier survival curves showed that the constructed prediction model classified malignant gliomas in a manner that better correlates with clinical outcome than standard histopathology.

CONCLUSIONS

Prediction models based on data-mining algorithms can provide a more accurate predictor of prognosis in malignant gliomas than histopathologic classification alone.

Downregulation of PCDH9 predicts prognosis for patients with glioma

Recent evidence has indicated that biological markers are essential in estimating the prognosis of patients with gliomas. The aim of this study was to determine the status and clinical significance of a novel tumor suppressor, PCDH9 (protocadherin 9) in glioma using tissue microarrays and immunohistochemistry. Normal brain tissue showed strong positive immunostaining for PCDH9, but this was downregulated in the primary cerebral glial tumor samples (51.7%). Loss of PCDH9 expression was associated significantly with a higher histological grade. Survival analysis demonstrated that patients with PCDH9-negative tumors had significantly shorter survival times than those with PCDH9-positive tumors and that PCDH9 was an independent prognostic factor. Our results suggest that PCDH9 might function as a tumor suppressor during cancer development and progression and could be regarded as a useful biomarker for predicting the outcome of patients with cerebral glial tumors.

Time-lapse imaging of disease progression in deep brain areas using fluorescence microendoscopy

The combination of intravital microscopy and animal models of disease has propelled studies of disease mechanisms and treatments. However, many disorders afflict tissues inaccessible to light microscopy in live subjects. Here we introduce cellular-level time-lapse imaging deep within the live mammalian brain by one- and two-photon fluorescence microendoscopy over multiple weeks. Bilateral imaging sites allowed longitudinal comparisons within individual subjects, including of normal and diseased tissues. Using this approach, we tracked CA1 hippocampal pyramidal neuron dendrites in adult mice, revealing these dendrites' extreme stability and rare examples of their structural alterations. To illustrate disease studies, we tracked deep lying gliomas by observing tumor growth, visualizing three-dimensional vasculature structure and determining microcirculatory speeds. Average erythrocyte speeds in gliomas declined markedly as the disease advanced, notwithstanding significant increases in capillary diameters. Time-lapse microendoscopy will be applicable to studies of numerous disorders, including neurovascular, neurological, cancerous and trauma-induced conditions.

Daily intake of antioxidants in relation to survival among adult patients diagnosed with malignant glioma

BACKGROUND

Malignant glioma is a rare cancer with poor survival. The influence of diet and antioxidant intake on glioma survival is not well understood. The current study examines the association between antioxidant intake and survival after glioma diagnosis.

METHODS

Adult patients diagnosed with malignant glioma during 1991-1994 and 1997-2001 were enrolled in a population-based study. Diagnosis was confirmed by review of pathology specimens. A modified food-frequency questionnaire interview was completed by each glioma patient or a designated proxy. Intake of each food item was converted to grams consumed/day. From this nutrient database, 16 antioxidants, calcium, a total antioxidant index and 3 macronutrients were available for survival analysis. Cox regression estimated mortality hazard ratios associated with each nutrient and the antioxidant index adjusting for potential confounders. Nutrient values were categorized into tertiles. Models were stratified by histology (Grades II, III, and IV) and conducted for all (including proxy) subjects and for a subset of self-reported subjects.

RESULTS

Geometric mean values for 11 fat-soluble and 6 water-soluble individual antioxidants, antioxidant index and 3 macronutrients were virtually the same when comparing all cases (n=748) to self-reported cases only (n=450). For patients diagnosed with Grade II and Grade III histology, moderate (915.8-2118.3 mcg) intake of fat-soluble lycopene was associated with poorer survival when compared to low intake (0.0-914.8 mcg), for self-reported cases only. High intake of vitamin E and moderate/high intake of secoisolariciresinol among Grade III patients indicated greater survival for all cases. In Grade IV patients, moderate/high intake of cryptoxanthin and high intake of secoisolariciresinol were associated with poorer survival among all cases. Among Grade II patients, moderate intake of water-soluble folate was associated with greater survival for all cases; high intake of vitamin C and genistein and the highest level of the antioxidant index were associated with poorer survival for all cases.

CONCLUSIONS

The associations observed in our study suggest that the influence of some antioxidants on survival following a diagnosis of malignant glioma are inconsistent and vary by histology group. Further research in a large sample of glioma patients is needed to confirm/refute our results.

Correlation of tumor topography and peritumoral edema of recurrent malignant gliomas with therapeutic response to intranasal administration of perillyl alcohol

BACKGROUND

The aim of this study was to establish a correlation of tumor topography and peritumoral brain edema with the therapeutic response to intranasal administration of perillyl alcohol (POH) in a cohort of patients with recurrent malignant gliomas.

METHODS

The retrospective study reviewed clinical and neuroradiological data from patients with recurrent malignant gliomas who received intranasal daily administration of POH 440 mg. The following parameters were assessed: demographic characteristics, initial symptoms, overall survival, tumor topography and tumor size, presence of midline shift and extent of peritumoral edema. Statistical analysis was carried out with log rank tests and overall survival as assessed by Kaplan-Meier method including 95% confidence intervals.

RESULTS

A cohort of 67 patients included 52 (78%) with glioblastoma (GBM), ten (15%) with anaplastic astrocytoma (AA) and five (7%) with anaplastic oligodendroglioma (AO). Accordingly to tumor topography lobar localization was present in all (5/5) AO; eight (8/10) and 41 GBM patients whereas in the basal ganglia two AA and 11 GBM patients. It was also observed a relation between the tumor size and area of peritumoral brain edema (PTBE). Patients with good therapeutic response showed reduction of tumor size and PTBE area, but poor prognosis was associated with lack of response to treatment and persistence of high PTBE. Patients with tumor in the basal ganglia survived significantly longer than those with lobar gliomas (log rank test, p = 0.0003). Presence of midline shift (>1 cm) was a statistically significant risk factor for shorter survival (log rank test, p = 0.0062)

CONCLUSIONS

This study suggests that: (1) patients with recurrent gliomas with localization in the basal ganglia survive significantly longer than those with tumors at lobar localization; (2) presence of PTBE contributes to symptoms, likely to be implicated in the morbidity and invading potential of malignant gliomas. These findings support the theory that interaction between glioma cells at distinct brain microenvironment can influence the oncobiological behavior of glioma cells and ultimately to the prognosis.

Translational research in glioblastoma multiforme: molecular criteria for patient selection

In spite of the dismal outcome of glioblastoma multiforme (GBM), we are in a position to provide a ray of hope to patients and families. Methylation of MGMT in tumor occurs in approximately a third of patients and predicts meaningful response and survival to adjuvant radiotherapy plus temozolomide. Limited access to tumor tissue in some patients could be circumvented by examining MGMT methylation in circulating serum DNA, although this approach needs to be validated. Molecular signatures are also promising prognostic and predictive markers, and clinical trials should be carried out to validate their use in the selection of patients for specific targeted therapies. Gene expression by quantitative PCR of key components of these molecular signatures could pave the way for easy identification of different subgroups of patients. Translational clinical trials are warranted in order to detect the subgroups of patients resistant to radiotherapy who may derive benefit from novel therapies, including antiangiogenic drugs.

Autocrine factors that sustain glioma invasion and paracrine biology in the brain microenvironment

Invasion is a defining hallmark of glioblastoma multiforme, just as metastasis characterizes other high-grade tumors. Glial tumors invariably recur due to the regrowth of invasive cells, which are unaffected by standard treatment modalities. Drivers of glioma invasion include autocrine signals propagated by secreted factors that signal through receptors on the tumor. These secreted factors are able to diffuse through the peritumoral stroma, thereby influencing parenchymal cells that surround the tumor mass. Here we describe various autocrine motility factors that are expressed by invasive glioma cells and explore the effects that they may have on normal cells present in the path of invasion. Conversely, normal brain parenchymal cells secrete ligands that can stimulate receptors on invasive glioma cells and potentially facilitate glioma invasion or create a permissive microenvironment for malignant progression. Parallel observations have been made for solid tumors of epithelial origin, in which parenchymal and stromal cells either support or suppress tumor invasion. Most autocrine and paracrine interactions involved in glioma invasion constitute known signaling systems in stages of central nervous system development that involve the migration of precursor cells that populate the developing brain. Key paracrine interactions between glioma cells and the brain microenvironment can influence glioma pathobiology and therefore contribute to its poor prognosis. Current therapies for glioma that could have an impact on paracrine communication between tumors and normal cells are discussed. We suggest that cells in the normal brain parenchyma be considered as potential targets for adjuvant therapies to control glioma growth because such cells are less likely to develop resistance than glioma cells.