Meningioma: International Consortium on Meningiomas consensus review on scientific advances and treatment paradigms for clinicians, researchers, and patients

Chromosome 1p Loss and 1q Gain for Grading of Meningioma

Importance

The World Health Organization (WHO) classification of central nervous system tumors (CNS) grading for meningioma was updated in 2021 to include rare molecular features, namely homozygous deletions of CDKN2A or CDKN2B and TERT promotor alterations. Previous work, including the cIMPACT-NOW statement, has discussed the potential value of including chromosomal copy number alterations to help refine the current grading system.

Objective

To identify chromosomal copy number alterations that could be used to improve the current CNS WHO grading of meningioma.

Design, Setting, and Participants

In this cohort study, patients with surgically treated meningioma were followed-up until recurrence or progression of disease or death. Chromosomal copy number alterations were then correlated with progression-free survival (PFS) to identify new outcome biomarkers. This study included patients with a histopathological diagnosis of meningioma from multiple institutions in Canada, the US, and Germany, with molecular data collection starting in 2016. Data were analyzed from January to September 2024.

Exposures

All patients underwent surgery for meningioma and a subset underwent radiation therapy.

Main Outcomes and Measures

The main outcome was PFS. Cox regression analysis was used to identify copy number alterations associated with outcomes in the context of WHO grading.

Results

Among 1964 patients with meningioma (1256 female; median [IQR] age, 58 [48-69] years) assessed, loss of chromosome 1p in WHO grade 1 meningiomas was associated with significantly worse outcomes compared with tumors without loss of 1p (median PFS, 5.83 [95% CI, 4.36-∞] years vs 34.54 [95% CI, 16.01-∞] years; log-rank P < .001). Outcomes of patients with WHO grade 1 tumors with loss of chromosome 1p were comparable to those of patients with WHO grade 2 tumors (median PFS, 4.48 [95% CI, 4.09-5.18] years). Combined loss of chromosome 1p and gain of chromosome 1q were associated with outcomes that were highly concordant with WHO grade 3 tumors, regardless of initial grade (median PFS: grade 1, 2.23 [95% CI, 1.28-∞] years; grade 2, 1.90 [95% CI, 1.23-2.25] years; grade 3, 2.27 [95% CI, 1.68-3.05] years).

Conclusions and Relevance

These findings highlight a role for cytogenetic profiling in the next iteration of CNS WHO grading, with a specific focus on chromosome 1p loss and 1q gain, suggesting that chromosome 1p loss, in addition to 22q loss, should be added as a criterion for a CNS WHO grade of 2 and addition of 1q gain as a criterion for a CNS WHO grade of 3.

Fast Fluid-Attenuated T2 Mapping via Multiple OverLapping-Echo Detachment Acquisition Enhances Preoperative Histological Classification of Meningiomas

Fluid-attenuated inversion recovery (FLAIR) is indispensable in MRI-based head-and-neck assessments, but its quantitative counterpart remains clinically absent due to the influence of cerebrospinal fluid (CSF) dynamics and the lengthy acquisition time spent on a series of weighting-increasing images. This work implements and validates fast fluid-attenuated T2 (FLA-T2) mapping via inversion-recovery-prepared multiple overlapping-echo detachment imaging (IR-MOLED). The clinical value is prospectively investigated with a cohort of 54 meningioma patients (mean age: 56 years ± 11 [standard deviation]; 19 men). Fluid-attenuated proton density mapping was simultaneously fulfilled and therefore intrinsically co-registered, revealing notable benefits in identifying CSF inflow. In quantifying parenchymal T2, IR-MOLED yielded a mean absolute error of 1.22 ms referring to spin-echo, and in fluid suppression, IR-MOLED exhibited a high radiographic consistence with orthodox FLAIR imaging. Using first-level histogram analysis, results of meningioma investigation first discovered: (1) in grading meningiomas, FLA-T2 mapping (AUC = 0.814) outshined FLAIR imaging (AUC = 0.685), contrast-enhanced T1-weighted imaging (insignificant), and T2 mapping (insignificant); and (2) in typing meningiomas, FLA-T2 classified transitional meningiomas from meningothelial or/and fibrous meningiomas, complementing the predictive ability of T2 mapping. In conclusion, with excluded parametric contribution from free water and standardized voxel value scales, FLA-T2 mapping permits a more precise description of brain parenchyma in both structural morphology and relaxation variables than T2 mapping and is fully superior to FLAIR imaging in preoperatively predicting the histopathologic heterogeneity of meningiomas.

Generalized Seizure as an Acute post-[177Lu]Lu-DOTATATE Side Effect in a Case of Recurrent Meningioma

[177Lu]Lu-DOTATATE is a newly trending acceptable therapy in recurrent/residual meningioma with good safety. However, recognizing any possible side effects in this special population would be helpful for better management and individualization of this useful treatment. Although the seizure has been previously reported in a few cases after [177Lu]Lu-DOTATATE therapy in recurrent meningioma, the acute onset of seizure in these patients, early after therapeutic radioligand administration, is not reported to the best of our knowledge. This report presents a case with the progression of residual meningioma after previous surgery in 2016 who developed with generalized tonic-clonic seizure, a few hours after administration of 200 mCi [177Lu]Lu-DOTATATE. The patient was taking prophylactic doses of the lacosamide, although no previous history of seizure was reported.

Meningioma: Novel Diagnostic and Therapeutic Approaches

Background/Objectives: Meningiomas are the most common intracranial tumors. Surgery and radiation therapy are the cornerstones of treatment and no standard of care therapy exists for refractory meningiomas. This manuscript aims to provide a comprehensive review of novel diagnostic and therapeutic approaches against these tumors. Methods: A search for the existing literature on systemic therapies for meningiomas was performed on PubMed and a search for presently accruing clinical trials was performed on ClinicalTrials.gov. Results: Systemic treatments, including chemotherapy, somatostatin analogs, anti-hormone therapy, and anti-angiogenic therapy, have been extensively studied with marginal success. Targeted therapies are actively being studied for the treatment of meningiomas, including focal adhesion kinase (FAK), sonic hedgehog signaling pathway, phosphoinositide-3-kinase (PI3K), and cyclin-dependent kinases (CDK) inhibitors. These driver mutations are present only in a subset of meningiomas. In stark contrast, somatostatin receptor 2 (SSTR2) is ubiquitously expressed in meningiomas and was formerly targeted with somatostatin analogs with modest success. Theranostic SSTR2-targeting via [68Ga]DOTATATE for PET imaging and β-emitting [177Lu]DOTATATE for the treatment of meningiomas are currently under active investigation. Conclusions: A nuanced approach is needed for the treatment of refractory meningiomas. Targeted therapies show promise.

Radiation Therapy for Meningiomas - Where Do We Stand and What's on the Horizon?

Radiation therapy, including conventionally fractionated external beam radiation therapy, stereotactic radiosurgery, and fractionated stereotactic radiation therapy, is a cornerstone in the interdisciplinary management of meningiomas. Recent advances in radiation oncology and also in other fields, such as neuropathology and imaging, have various implications for meningioma radiation therapy. This review aims to summarize current and anticipated developments, as well as active clinical trials related to the use of radiation therapy for meningiomas. In imaging, positron emission tomography has proven valuable for assessing the spatial extension of meningiomas and may enhance target delineation, treatment response monitoring, and recurrence assessment after radiation therapy. Particle therapy, including protons and carbon ions, as well as stereotactic radiosurgery and fractionated stereotactic radiation therapy, allow for conformal treatments that permit dose escalation in selected patients with high-grade meningiomas. Additionally, emerging integrated molecular and genetic classifications offer superior risk stratification and may refine patient selection for radiation therapy. However, there is a paucity of active meningioma trials directly investigating or refining the use of radiation therapy. In summary, significant advances in functional imaging, molecular and genetic diagnostics, and radiation treatment techniques hold the potential to improve patient outcomes and to avoid over- and undertreatment. Collaborative efforts and further clinical trials are essential to optimize meningioma radiation therapy.

Pathological diagnosis of central nervous system tumours in adults: what's new?

In the course of the last decade, the pathological diagnosis of many tumours of the central nervous system (CNS) has transitioned from a purely histological to a combined histological and molecular approach, resulting in a more precise 'histomolecular diagnosis'. Unfortunately, translation of this refinement in CNS tumour diagnostics into more effective treatment strategies is lagging behind. There is hope though that incorporating the assessment of predictive markers in the pathological evaluation of CNS tumours will help to improve this situation. The present review discusses some novel aspects with regard to the pathological diagnosis of the most common CNS tumours in adults. After a brief update on recognition of clinically meaningful subgroups in adult-type diffuse gliomas and the value of assessing predictive markers in these tumours, more detailed information is provided on predictive markers of (potential) relevance for immunotherapy especially for glioblastomas, IDH-wildtype. Furthermore, recommendations for improved grading of meningiomas by using molecular markers are briefly summarised, and an overview is given on (predictive) markers of interest in metastatic CNS tumours. In the last part of this review, some 'emerging new CNS tumour types' that may occur especially in adults are presented in a table. Hopefully, this review provides useful information on 'what's new' for practising pathologists diagnosing CNS tumours in adults.

The role of meningioma integrated molecular profiling to improve patient management and disclose novel therapeutic targets

This scientific commentary refers to 'Integrating genome-wide association studies and transcriptomics prioritizes drug targets for meningioma', by Liao et al. (https://doi.org/10.1093/braincomms/fcaf053).

Malignant Meningiomas: From Diagnostics to Treatment

Meningiomas account for approximately 40% of all primary brain tumors, of which 1.5% are classified as grade 3. Whilst meningiomas are discovered on imaging with high-grade meningiomas being associated with certain imaging features, the final diagnosis is based on histopathology in combination with molecular markers. According to the latest World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS), grade 3 should be assigned based on criteria for anaplastic meningiomas, which comprise malignant cytomorphology (anaplasia) that resembles carcinoma, high-grade sarcoma or melanoma; elevated mitotic activity; a TERT promoter mutation and/or a homozygous CDKN2A and/or CDKN2B deletion. Surgery remains the mainstay treatment modality for grade 3 meningiomas, followed by radiotherapy. Limited data are available on the effect of stereotactic radiosurgery and systemic therapy for grade 3 meningiomas; however, studies are underway. Despite optimal treatment, the estimated recurrence rate ranges between 50% and 95% with a 5-year survival rate of 66% and a 10-year estimated survival rate of 14% to 24%.

Stroke in adults with primary intracranial tumours

BACKGROUND

We investigated stroke in patients with either benign or malignant primary intracranial tumours to give insights into how malignant and non-malignant intracranial tumours affect stroke and to provide evidence for stroke guidelines for these patients.

METHODS

We conducted a retrospective cohort study of patients with benign or malignant primary intracranial tumours admitted with stroke (2011-2022) to a single centre with regional stroke and neuro-oncology units. Data collected included: stroke aetiology, stroke timing relative to tumour diagnosis, pre-stroke disability, post-stroke disability, stroke recurrence and treatment.

RESULTS

We identified 258 patients who had an index stroke (120 haemorrhagic, 135 ischaemic, three coincident haemorrhagic/ischaemic) at or after the diagnosis of their primary intracranial tumour (71% benign, 29% malignant). Stroke incidence spiked at tumour diagnosis and subsequent months. Symptomatic intracranial haemorrhage was more commonly associated with malignant primary intracranial tumours. In-hospital mortality and level of disability at hospital discharge (median modified Rankin scale score, 4) were similar for patients with benign or malignant primary intracranial tumours. Stroke recurrence was 22% at one year. Statins were associated with reduced stroke recurrence (HR = 0.35 [95% CI 0.13-0.96]). The probability of patients with malignant tumours receiving chemotherapy was inversely related to disability at hospital discharge (ratio OR per unit increase modified Rankin scale = 0.65 [95% CI 0.42-0.96]).

CONCLUSION

Stroke has wider consequences for patients with primary intracranial tumours than commonly recognised. Our data indicated that statins may help to prevent stroke recurrence. Despite concerns about intracranial haemorrhage, antiplatelet agents should be considered after ischaemic stroke.

Grade-stratified meningioma risk among individuals who are non-Hispanic Black and interactions with male sex

BACKGROUND

Meningioma risk factors include older age, female sex, and being Black/African American. Limited data explore how meningioma risk in individuals who are Black varies across the lifespan, interacts with sex, and differs by tumor grade.

METHODS

The Central Brain Tumor Registry of the United States is a population-based registry covering the entire US population. Meningioma diagnoses from 2004 to 2019 were used to calculate incidence rate ratios for non-Hispanic Black individuals compared with non-Hispanic White individuals across 10-year age intervals and stratified by sex and World Health Organization tumor grade in this retrospective study.

RESULTS

A total of 53 890 non-Hispanic Black individuals and 322 373 non-Hispanic White individuals with an intracranial meningioma diagnosis were included in analyses. Beginning in young adulthood, the non-Hispanic Black to non-Hispanic White incidence rate ratio was elevated for grade 1 and grades 2-3 tumors. The incidence rate ratio peaked in the seventh decade of life regardless of grade and was higher for grades 2-3 tumors (incidence rate ratio  = 1.57, 95% confidence interval [CI] = 1.46 to 1.69) than grade 1 tumors (incidence rate ratio = 1.27, 95% CI = 1.25 to 1.30) in this age group. The non-Hispanic Black to non-Hispanic White incidence rate ratio was elevated in women (incidence rate ratio = 1.17, 95% CI = 1.16 to 1.18) and was further elevated in men (incidence rate ratio = 1.28, 95% CI = 1.26 to 1.30), revealing synergistic interaction between non-Hispanic Black race and ethnicity and male sex (Pinteraction = .001).

CONCLUSIONS

Relative to non-Hispanic White individuals, non-Hispanic Black individuals are at elevated risk of meningioma from young adulthood through old age. Non-Hispanic Black race and ethnicity conferred greater risk of meningioma among men than women and greater risk of grades 2-3 tumors. Population-level differences in meningioma incidence and tumor behavior suggest potential disparities in the geographic, socioeconomic, and racial distribution of meningioma risk factors within the United States.

A multi-modal deep learning model for prediction of Ki-67 for meningiomas using pretreatment MR images

This study developed and validated a deep learning network using baseline magnetic resonance imaging (MRI) to predict Ki-67 status in meningioma patients. A total of 1239 patients were retrospectively recruited from three hospitals between January 2010 and December 2023, forming training, internal validation, and two external validation cohorts. A representation learning framework was utilized for modeling, and performance was assessed against existing methods. Furthermore, Kaplan-Meier survival analysis was conducted to investigate whether the model could be used for tumor growth prediction. The model achieved superior results, with areas under the curve (AUCs) of 0.797 for internal testing and 0.808 for generalization, alongside 0.756 and 0.727 for 3- and 5-year tumor growth predictions, respectively. The prediction was significantly associated with the growth of asymptomatic small meningiomas. Overall, the model provides an effective tool for early prediction of Ki-67 and tumor volume growth, aiding in individualized patient management.

Long Non-Coding RNAs in Malignant Human Brain Tumors: Driving Forces Behind Progression and Therapy

Long non-coding RNAs (lncRNAs) play a pivotal role in regulating gene expression and are critically involved in the progression of malignant brain tumors, including glioblastoma, medulloblastoma, and meningioma. These lncRNAs interact with microRNAs (miRNAs), proteins, and DNA, influencing key processes such as cell proliferation, migration, and invasion. This review highlights the multifaceted impact of lncRNA dysregulation on tumor progression and underscores their potential as therapeutic targets to enhance the efficacy of chemotherapy, radiotherapy, and immunotherapy. The insights provided offer new directions for advancing basic research and clinical applications in malignant brain tumors.

The Impact of MRI-Defined Extent of Resection Across Meningioma DNA Methylation Groups: Re-Evaluating Surgery in the Era of Meningioma Molecular Classification

BACKGROUND AND OBJECTIVES

Extent of resection (EOR) is prognostic for meningioma outcomes. DNA methylation profiling can shed light on biological drivers and therapeutic vulnerabilities. The goal of this study was to re-evaluate the impact of EOR on clinical outcomes across meningioma DNA methylation groups.

METHODS

Patients with sporadic meningiomas who underwent resection from a multicenter, international cohort were retrospectively reviewed. Gross vs subtotal resection (GTR vs STR, respectively) was determined based on postoperative MRI. The Kaplan-Meier method, log-rank statistics, and multivariable Cox proportional hazard analyses were performed to evaluate the impact of EOR on local freedom from recurrence (LFFR) and overall survival (OS).

RESULTS

In total, 587 patients (Male: 195, Female: 392) underwent 644 surgeries for intracranial meningioma (GTR: 438, STR: 206), with 124 surgeries (19.3%) for recurrent intracranial meningiomas. The cohort included 375 (58.2%) World Health Organization (WHO) Grade 1, 202 (31.4%) WHO Grade 2, and 67 (10.4%) WHO Grade 3 meningiomas based on histological criteria. DNA methylation profiling was used to categorize meningiomas as Merlin-intact (N = 214, 33.2%), Immune-enriched (N = 236, 36.6%), or Hypermitotic (N = 194, 30.1%). GTR was associated with longer LFFR across all meningioma DNA methylation groups (Merlin-intact P < .0001; Immune-enriched P = .013; Hypermitotic P = .001) and was associated with longer OS for Hypermitotic meningiomas (P = .0022). In multivariable Cox proportional hazard analyses, EOR was significantly associated with LFFR across all DNA methylation groups and WHO grades but was significantly associated with OS only for Hypermitotic meningiomas (hazard ratio [GTR vs STR] 0.64, 95% CI 0.43-0.97, P = .034).

CONCLUSION

MRI-defined GTR is associated with improved LFFR across all meningioma DNA methylation groups and improved OS for patients with Hypermitotic meningiomas. These data continue to support maximal safe resection when feasible and demonstrate how molecular classification systems complement rather than supersede the prognostic impact of surgery.

Orthotopic meningioma rat model exhibits morphological and immunohistochemical congruency and epigenetic concordance with benign primary patient-derived tumors

Meningiomas are the most common primary central nervous system tumor. Clinical trials have failed to support effective medical treatments, despite initially promising animal studies. A key issue could be that available experimental models fail to mimic the clinical situation. Hence, there is a need for meningioma models with high translational value for understanding pathophysiology and tests of possible medical treatments. Resemblance between models and clinical meningiomas should be optimized with respect to morphology, immunohistochemistry and epigenetic factors, which we aimed to do. Third passage primary patient-derived benign meningiomas were implanted intracranially in athymic nude rats. The animals were euthanized after three months. We found intra- and intertumoral variability in terms of tumor take rate (79.5% for superficially implanted cells and 25% for deeply implanted cells) and xenograft sizes. There were close resemblance between primary tumors and xenografts in morphology and immunohistochemistry. Furthermore, we performed DNA-methylation using the EPIC 850 K array on three pairs of primary tumors and xenografts. Copy number variation profiles and correlation plots on CpGs showed a high degree of similarities between primary tumors and corresponding xenografts. On differential methylation analysis, most probes were insignificant (866,074), 25 were hypermethylated, and 382 were hypomethylated, where no significant differentially methylated regions were revealed.

Methylation profiling in the contemporary management of meningioma

BACKGROUND

The last decade has seen major international research efforts focus on better understanding disease heterogeneity in meningioma. Multiple molecular platforms have generated significant biological and clinical utility, and there is a need to translate these findings into routine clinical practice. Here we review the role of DNA methylation profiling in meningioma and advocate for its widespread adoption.

METHODS

We review modern DNA methylation-based classification and outcome prediction tools in meningioma. Biological classifiers, which were constructed agnostic to outcome using unsupervised approaches, outcome predictors, and liquid biopsy models are discussed in detail.

RESULTS

DNA methylation has been used for biological classification and outcome in meningioma with considerable success. Several groups have proposed novel molecular classification systems which share similar features with one another and outperform WHO grade in their ability to predict outcome and explain subgroup-specific biological processes. In addition, recent studies have suggested a role for methylation-based liquid-biopsy in meningioma, which represents an exciting avenue for further exploration.

CONCLUSIONS

DNA methylation profiling has been revolutionary in meningioma. There is a need for widespread adoption of these approaches to personalize care and inform clinical trial design.

Neurofibromatosis type 2-related schwannomatosis - An update

Neurofibromatosis type 2-related schwannomatosis (NF2-SWN) is an autosomal dominant inherited disorder with 100 % penetrance associated with pathogenic variants of the NF2 gene on the long arm of chromosome 22. It was previously known as central neurofibromatosis and neurofibromatosis type 2. NF2-SWN has a global incidence of about 1 in 50,000. This disorder is characterized by the formation of multiple types of central nervous system tumors. While bilateral vestibular schwannomas affect more than 95 % of individuals with NF2-SWN, meningiomas, ependymomas, gliomas, other schwannomas, and ophthalmologic abnormalities are also common. Careful dermatologic, ophthalmologic, and neurologic examination can identify signs of NF2-SWN to allow timely initiation of disease specific treatment. Most patients benefit from multimodal treatment, including surgery.

Cancer stem cells in meningiomas: novel insights and therapeutic implications

Meningiomas (MGs), which arise from meningothelial cells of the dura mater, represent a significant proportion of primary tumours of the central nervous system (CNS). Despite advances in treatment, the management of malignant meningioma (MMG) remains challenging due to diagnostic, surgical, and resection limitations. Cancer stem cells (CSCs), a subpopulation within tumours capable of self-renewal and differentiation, are highlighted as key markers of tumour growth, metastasis, and treatment resistance. Identifying additional CSC-related markers enhances the precision of malignancy evaluations, enabling advancements in personalised medicine. The review discusses key CSC biomarkers that are associated with high levels of expression, aggressive tumour behaviour, and poor outcomes. Recent molecular research has identified CSC-related biomarkers, including Oct-4, Sox2, NANOG, and CD133, which help maintain cellular renewal, proliferation, and drug resistance in MGs. This study highlights new therapeutic strategies that could improve patient prognosis with more durable tumour regression. The use of combination therapies, such as hydroxyurea alongside diltiazem, suggests more efficient and effective MG management compared to monotherapy. Signalling pathways such as NOTCH and hedgehog also offer additional avenues for therapeutic development. CRISPR/Cas9 technology has also been employed to create meningioma models, uncovering pathways related to cell growth and proliferation. Since the efficacy of traditional therapies is limited in most cases due to resistance mechanisms in CSCs, further studies on the biology of CSCs are warranted to develop therapeutic interventions that are likely to be effective in MG. Consequently, improved diagnostic approaches may lead to personalised treatment plans tailored to the specific needs of each patient.

Elevated meningioma risk among individuals who are Non-Hispanic Black is strongest for grade 2-3 tumors and synergistically modified by male sex

Background

Meningioma risk factors include older age, female sex, and African-American race. There are limited data exploring how meningioma risk in African-Americans varies across the lifespan, interacts with sex, and differs by tumor grade.

Methods

The Central Brain Tumor Registry of the United States (CBTRUS) is a population-based registry covering the entire U.S. population. Meningioma diagnoses from 2004-2019 were used to calculate incidence rate ratios (IRRs) for non-Hispanic Black individuals (NHB) compared to non-Hispanic white individuals (NHW) across 10-year age intervals, and stratified by sex and by WHO tumor grade.

Results

53,890 NHB individuals and 322,373 NHW individuals with an intracranial meningioma diagnosis were included in analyses. Beginning in young adulthood, the NHB-to-NHW IRR was elevated for both grade 1 and grade 2/3 tumors. The IRR peaked in the seventh decade of life regardless of grade, and was higher for grade 2/3 tumors (IRR=1.57; 95% CI: 1.46-1.69) than grade 1 tumors (IRR=1.27; 95% CI: 1.25-1.30) in this age group. The NHB-to-NHW IRR was elevated in females (IRR=1.17; 95% CI: 1.16-1.18) and further elevated in males (IRR=1.28; 95% CI: 1.26-1.30), revealing synergistic interaction between NHB race/ethnicity and male sex (P Interaction =0.001).

Conclusions

Relative to NHW individuals, NHB individuals are at elevated risk of meningioma from young adulthood through old age. NHB race/ethnicity conferred higher risk of meningioma among men than women, and higher risk of developing WHO grade 2/3 tumors. Results identify meningioma as a significant source of racial disparities in neuro-oncology and may help to improve preoperative predictions of meningioma grade.