A multi-center, clinical analysis of IDH-mutant gliomas, WHO Grade 4: implications for prognosis and clinical trial design.

PURPOSE: Mutations in the Isocitrate Dehydrogenase (IDH) genes, IDH1 or IDH2, define a group of adult diffuse gliomas associated with a younger age at diagnosis and better prognosis than IDH wild-type glioblastoma. Within IDH mutant gliomas, a small fraction of astrocytic tumors present with grade 4 histologic features and poor prognosis. In molecular studies, homozygous deletion of CDKN2A/B is independently predictive of poor prognosis and short survival. As a consequence, 2021 WHO classification now also recognizes this molecular feature, CDKN2A/B deletion, as sufficient for classifying an astrocytoma as IDH-mutant, WHO Grade 4, regardless of histological grading. Here, we investigate outcomes of patients with WHO Grade 4 IDH-mutant astrocytoma both with and without CDKN2A/B deletion, to compare these groups and evaluate clinical and radiographic factors that contribute to survival. METHODS: We retrospectively identified 79 patients with IDH-mutant astrocytoma with CDKN2A/B deletion detected at initial diagnosis across five international institutions as well as a comparison group of 51 patients with IDH-mutant, astrocytoma, histologically Grade 4 without detectable CDKN2A/B deletion. We assembled clinical and radiographic features for all patients. RESULTS: We find that CDKN2A/B deletion was associated with significantly worse overall survival (OS; p = 0.0004) and progression-free survival (PFS; p = 0.0026), with median OS of 5.0 years and PFS of 3.0 years, compared to 10.1 and 5.0 years for tumors with a grade 4 designation based only on histologic criteria. Multivariate analysis confirmed CDKN2A/B deletion as a strong negative prognosticator for both OS (HR = 3.51, p < 0.0001) and PFS (HR = 2.35, p = 0.00095). In addition, in tumors with CDKN2A/B deletion, preoperative contrast enhancement is a significant predictor of worse OS (HR 2.19, 95% CI 1.22-3.93, p = 0.0090) and PFS (HR = 1.74, 95% CI = 1.02-2.97, p = 0.0420). CONCLUSIONS: These findings underscore the severe prognostic impact of CDKN2A/B deletion in IDH-mutant astrocytomas and highlight the need for further refinement of tumor prognostic categorization. Our results provide a key benchmark of baseline patient outcomes for therapeutic trials, underscoring the importance of CDKN2A/B status assessment, in addition to histologic grading, in clinical trial design and therapeutic decision-making for IDH-mutant astrocytoma patients.

Palliative care for in-patient malignant glioma patients in Germany.

OBJECTIVE: Malignant gliomas impose a significant symptomatic burden on patients and their families. Current guidelines recommend palliative care for patients with advanced tumors within eight weeks of diagnosis, emphasizing early integration for malignant glioma cases. However, the utilization rate of palliative care for these patients in Germany remains unquantified. This study investigates the proportion of malignant glioma patients who either died in a hospital or were transferred to hospice care from 2019 to 2022, and the prevalence of in-patient specialized palliative care interventions. METHODS: In this cross-sectional, retrospective study, we analyzed data from the Institute for the Hospital Remuneration System (InEK GmbH, Siegburg, Germany), covering 2019 to 2022. We included patients with a primary or secondary diagnosis of C71 (malignant glioma) in our analysis. To refine our dataset, we identified cases with dual-coded primary and secondary diagnoses and excluded these to avoid duplication in our final tally. The data extraction process involved detailed scrutiny of hospital records to ascertain the frequency of hospital deaths, hospice transfers, and the provision of complex or specialized palliative care for patients with C71-coded diagnoses. Descriptive statistics and inferential analyses were employed to evaluate the trends and significance of the findings. RESULTS: From 2019 to 2022, of the 101,192 hospital cases involving malignant glioma patients, 6,129 (6% of all cases) resulted in in-hospital mortality, while 2,798 (2.8%) led to hospice transfers. Among these, 10,592 cases (10.5% of total) involved the administration of complex or specialized palliative medical care. This provision rate remained unchanged throughout the COVID-19 pandemic. Notably, significantly lower frequencies of complex or specialized palliative care implementation were observed in patients below 65 years (p < 0.0001) and in male patients (padjusted = 0.016). In cases of in-hospital mortality due to malignant gliomas, 2,479 out of 6,129 cases (40.4%) received specialized palliative care. CONCLUSION: Despite the poor prognosis and complex symptomatology associated with malignant gliomas, only a small proportion of affected patients received advanced palliative care. Specifically, only about 10% of hospitalized patients with malignant gliomas, and approximately 40% of those who succumb to the disease in hospital settings, were afforded complex or specialized palliative care. This discrepancy underscores an urgent need to expand palliative care access for this patient demographic. Additionally, it highlights the importance of further research to identify and address the barriers preventing wider implementation of palliative care in this context.

Benchmarking palliative care practices in neurooncology: a german perspective.

PURPOSE: To benchmark palliative care practices in neurooncology centers across Germany, evaluating the variability in palliative care integration, timing, and involvement in tumor board discussions. This study aims to identify gaps in care and contribute to the discourse on optimal palliative care strategies. METHODS: A survey targeting both German Cancer Society-certified and non-certified university neurooncology centers was conducted to explore palliative care frameworks and practices for neurooncological patients. The survey included questions on palliative care department availability, involvement in tumor boards, timing of palliative care integration, and use of standardized screening tools for assessing palliative burden and psycho-oncological distress. RESULTS: Of 57 centers contacted, 46 responded (81% response rate). Results indicate a dedicated palliative care department in 76.1% of centers, with palliative specialists participating in tumor board discussions at 34.8% of centers. Variability was noted in the initiation of palliative care, with early integration at the diagnosis stage in only 30.4% of centers. The survey highlighted a significant lack of standardized spiritual care assessments and minimal use of advanced care planning. Discrepancies were observed in the documentation and treatment of palliative care symptoms and social complaints, underscoring the need for comprehensive care approaches. CONCLUSION: The study highlights a diverse landscape of palliative care provision within German neurooncology centers, underscoring the need for more standardized practices and early integration of palliative care. It suggests the necessity for standardized protocols and guidelines to enhance palliative care's quality and uniformity, ultimately improving patient-centered care in neurooncology.

In-patient neurosurgical tumor treatments for malignant glioma patients in Germany.

OBJECTIVE: Treatment for malignant gliomas involves multiple disciplines, including neurosurgery, radiation therapy, medical and neuro-oncology, and palliative medicine, with function-preserving neurosurgical tumor removal being crucial. However, real-world data on hospital cases, treatment types, especially regarding surgical approaches, and the associated complication and mortality rates in Germany are lacking. METHODS: We analyzed data on hospital cases involving malignant gliomas (ICD-10-GM code C71) from the German §21 Hospital Remuneration Act, provided by the Institute for the Hospital Remuneration System (InEK GmbH), from 2019 to 2022. Our focus was on neuro-oncological operations defined by the German Cancer Society (DKG) and included specific operation and procedure (OPS) codes. RESULTS: From 2019 to 2022, there were 101,192 hospital cases involving malignant gliomas in Germany. Neurosurgical tumor removal was performed in 27,193 cases (26.9%). Microsurgical techniques were used in 95% of surgeries, intraoperative navigation systems in 84%, fluorescence-guided surgeries in 45.6%, and intraoperative neurophysiological monitoring (IONM) in 46.4%. Surgical or medical complications occurred in 2903 cases (10.7%). The hospital mortality rate was 2.7%. Mortality was significantly higher in patients aged 65 and older (Odds ratio 2.9, p < 0.0001), and lower in cases using fluorescence-guided procedures (Odds ratio 0.8, p = 0.015) and IONM (Odds ratio 0.5, p < 0.0001). CONCLUSIONS: Over the course of 4 years, over 100,000 hospital cases involving adult patients diagnosed with malignant gliomas were treated in Germany, with 27,193 cases undergoing tumor removal using various modern surgical techniques. The hospital mortality rate was 2.7%.

Repeat surgery of recurrent glioma for molecularly informed treatment in the age of precision oncology: A risk-benefit analysis.

PURPOSE: Surgery for recurrent glioma provides cytoreduction and tissue for molecularly informed treatment. With mostly heavily pretreated patients involved, it is unclear whether the benefits of repeat surgery outweigh its potential risks. METHODS: Patients receiving surgery for recurrent glioma WHO grade 2-4 with the goal of tissue sampling for targeted therapies were analyzed retrospectively. Complication rates (surgical, neurological) were compared to our institutional glioma surgery cohort. Tissue molecular diagnostic yield, targeted therapies and post-surgical survival rates were analyzed. RESULTS: Between 2017 and 2022, tumor board recommendation for targeted therapy through molecular diagnostics was made for 180 patients. Of these, 70 patients (38%) underwent repeat surgery. IDH-wildtype glioblastoma was diagnosed in 48 patients (69%), followed by IDH-mutant astrocytoma (n = 13; 19%) and oligodendroglioma (n = 9; 13%). Gross total resection (GTR) was achieved in 50 patients (71%). Tissue was processed for next-generation sequencing in 64 cases (91%), and for DNA methylation analysis in 58 cases (83%), while immunohistochemistry for mTOR phosphorylation was performed in 24 cases (34%). Targeted therapy was recommended in 35 (50%) and commenced in 21 (30%) cases. Postoperatively, 7 patients (11%) required revision surgery, compared to 7% (p = 0.519) and 6% (p = 0.359) of our reference cohorts of patients undergoing first and second craniotomy, respectively. Non-resolving neurological deterioration was documented in 6 cases (10% vs. 8%, p = 0.612, after first and 4%, p = 0.519, after second craniotomy). Median survival after repeat surgery was 399 days in all patients and 348 days in GBM patients after repeat GTR. CONCLUSION: Surgery for recurrent glioma provides relevant molecular diagnostic information with a direct consequence for targeted therapy under a reasonable risk of postoperative complications. With satisfactory postoperative survival it can therefore complement a multi-modal glioma therapy approach.

Analysis of safety and efficacy of proton radiotherapy for IDH-mutated glioma WHO grade 2 and 3.

PURPOSE: Proton beam radiotherapy (PRT) has been demonstrated to improve neurocognitive sequelae particularly. Nevertheless, following PRT, increased rates of radiation-induced contrast enhancements (RICE) are feared. How safe and effective is PRT for IDH-mutated glioma WHO grade 2 and 3? METHODS: We analyzed 194 patients diagnosed with IDH-mutated WHO grade 2 (n = 128) and WHO grade 3 (n = 66) glioma who were treated with PRT from 2010 to 2020. Serial clinical and imaging follow-up was performed for a median of 5.1 years. RESULTS: For WHO grade 2, 61% were astrocytoma and 39% oligodendroglioma while for WHO grade 3, 55% were astrocytoma and 45% oligodendroglioma. Median dose for IDH-mutated glioma was 54 Gy(RBE) [range 50.4-60 Gy(RBE)] for WHO grade 2 and 60 Gy(RBE) [range 54-60 Gy(RBE)] for WHO grade 3. Five year overall survival was 85% in patients with WHO grade 2 and 67% in patients with WHO grade 3 tumors. Overall RICE risk was 25%, being higher in patients with WHO grade 2 (29%) versus in patients with WHO grade 3 (17%, p = 0.13). RICE risk increased independent of tumor characteristics with older age (p = 0.017). Overall RICE was symptomatic in 31% of patients with corresponding CTCAE grades as follows: 80% grade 1, 7% grade 2, 13% grade 3, and 0% grade 3 + . Overall need for RICE-directed therapy was 35%. CONCLUSION: These data demonstrate the effectiveness of PRT for IDH-mutated glioma WHO grade 2 and 3. The RICE risk differs with WHO grading and is higher in older patients with IDH-mutated Glioma WHO grade 2 and 3.

Impact of ABO-blood group type on haemorrhagic and thromboembolic complications after resection of intracranial meningiomas.

OBJECTIVE: Recent studies have suggested an impact of the ABO-blood group type on thromboembolic and haemorrhagic events following trauma and surgical procedures. However, only limited data are available on the impact of ABO-blood group types in neurosurgical patients. The goal of the present study was to evaluate the role of the ABO-blood group type on the frequency of thromboembolic and haemorrhagic complications in patients treated surgically for intracranial meningiomas at our institution. METHODS: We retrospectively analysed the medical records of consecutive patients undergoing resection of intracranial meningiomas at our institution during a period of 12.5 years (2006-2018). Clinical characteristics, modalities of surgical treatment, histopathological results and the postoperative course of patients were analysed with specific focus on ABO-blood group typing results, need for transfusion of blood products, events of postoperative thromboembolism and intracranial re-haemorrhage requiring surgical revision, as well as in-hospital mortality. RESULTS: A total of 1,782 patients were included in this study. Based on the ABO-blood group type, patients were subdivided into four categories, corresponding to their ABO-blood group: Blood group A (n = 773; 43%); blood group B (n = 222; 12%); blood group AB (n = 88; 5%); and blood group O (n = 699; 39%). Intracranial re-haemorrhage requiring re-craniotomy and haematoma evacuation occurred in a total of 49 patients (2.7%). Thromboembolic events such as pulmonary embolism occurred in a total of 27 patients (1.5%). Statistical analysis showed no significant differences regarding the ABO-blood group type in patients suffering from re-haemorrhage or thromboembolism compared with patients with uneventful course after surgery. The overall in-hospital mortality rate was 0.17% (n = 3). CONCLUSION: Our findings suggest a lack of relevance of the ABO-blood group type regarding haemorrhagic and thromboembolic complications in patients undergoing neurosurgical meningioma resection.

DNA-methylome-assisted classification of patients with poor prognostic subventricular zone associated IDH-wildtype glioblastoma.

Glioblastoma (GBM) derived from the "stem cell" rich subventricular zone (SVZ) may constitute a therapy-refractory subgroup of tumors associated with poor prognosis. Risk stratification for these cases is necessary but is curtailed by error prone imaging-based evaluation. Therefore, we aimed to establish a robust DNA methylome-based classification of SVZ GBM and subsequently decipher underlying molecular characteristics. MRI assessment of SVZ association was performed in a retrospective training set of IDH-wildtype GBM patients (n = 54) uniformly treated with postoperative chemoradiotherapy. DNA isolated from FFPE samples was subject to methylome and copy number variation (CNV) analysis using Illumina Platform and cnAnalysis450k package. Deep next-generation sequencing (NGS) of a panel of 130 GBM-related genes was conducted (Agilent SureSelect/Illumina). Methylome, transcriptome, CNV, MRI, and mutational profiles of SVZ GBM were further evaluated in a confirmatory cohort of 132 patients (TCGA/TCIA). A 15 CpG SVZ methylation signature (SVZM) was discovered based on clustering and random forest analysis. One third of CpG in the SVZM were associated with MAB21L2/LRBA. There was a 14.8% (n = 8) discordance between SVZM vs. MRI classification. Re-analysis of these patients favored SVZM classification with a hazard ratio (HR) for OS of 2.48 [95% CI 1.35-4.58], p = 0.004 vs. 1.83 [1.0-3.35], p = 0.049 for MRI classification. In the validation cohort, consensus MRI based assignment was achieved in 62% of patients with an intraclass correlation (ICC) of 0.51 and non-significant HR for OS (2.03 [0.81-5.09], p = 0.133). In contrast, SVZM identified two prognostically distinct subgroups (HR 3.08 [1.24-7.66], p = 0.016). CNV alterations revealed loss of chromosome 10 in SVZM- and gains on chromosome 19 in SVZM- tumors. SVZM- tumors were also enriched for differentially mutated genes (p < 0.001). In summary, SVZM classification provides a novel means for stratifying GBM patients with poor prognosis and deciphering molecular mechanisms governing aggressive tumor phenotypes.

Decision making and surgical modality selection in glioblastoma patients: an international multicenter survey.

PURPOSE: Due to the lack of consensus on the management of glioblastoma patients, there exists variability amongst surgeons and centers regarding treatment decisions. Though, objective data about the extent of this heterogeneity is still lacking. We aim to evaluate and analyze the similarities and differences in neurosurgical practice patterns. METHODS: The survey was distributed to members of the neurosurgical societies of the Netherlands (NVVN), Europe (EANS), the United Kingdom (SBNS) and the United States (CNS) between January and March 2021 with questions about the selection of surgical modality and decision making in glioblastoma patients. RESULTS: Survey respondents (224 neurosurgeons) were from 41 countries. Overall, the most notable differences observed were the presence and timing of a multidisciplinary tumor board; the importance and role of various perioperative factors in the decision-making process, and the preferred treatment in various glioblastoma cases and case variants. Tumor boards were more common at academic centers. The intended extent of resection for glioblastoma resections in eloquent areas was limited more often in European neurosurgeons. We found a strong relationship between the surgeon's theoretical survey answers and their actual approach in presented patient cases. In general, the factors which were found to be theoretically the most important in surgical decision making were confirmed to influence the respondents' decisions to the greatest extent in practice as well. DISCUSSION: This survey illustrates the theoretical and practical heterogeneity among surgeons and centers in their decision making and treatment selection for glioblastoma patients. These data invite further evaluations to identify key variables that can be optimized and may therefore benefit from consensus.

Proposed definition of competencies for surgical neuro-oncology training.

OBJECTIVE: The aim of this work is to define competencies and entrustable professional activities (EPAs) to be imparted within the framework of surgical neuro-oncological residency and fellowship training as well as the education of medical students. Improved and specific training in surgical neuro-oncology promotes neuro-oncological expertise, quality of surgical neuro-oncological treatment and may also contribute to further development of neuro-oncological techniques and treatment protocols. Specific curricula for a surgical neuro-oncologic education have not yet been established. METHODS: We used a consensus-building approach to propose skills, competencies and EPAs to be imparted within the framework of surgical neuro-oncological training. We developed competencies and EPAs suitable for training in surgical neuro-oncology. RESULT: In total, 70 competencies and 8 EPAs for training in surgical neuro-oncology were proposed. EPAs were defined for the management of the deteriorating patient, the management of patients with the diagnosis of a brain tumour, tumour-based resections, function-based surgical resections of brain tumours, the postoperative management of patients, the collaboration as a member of an interdisciplinary and/or -professional team and finally for the care of palliative and dying patients and their families. CONCLUSIONS AND RELEVANCE: The present work should subsequently initiate a discussion about the proposed competencies and EPAs and, together with the following discussion, contribute to the creation of new training concepts in surgical neuro-oncology.

The anesthetist's choice of inhalational vs. intravenous anesthetics has no impact on survival of glioblastoma patients.

Recent data suggest that the type of anesthesia used during the resection of solid tumors impacts the long-term survival of patients favoring total-intravenous-anesthesia (TIVA) over inhalative-anesthesia (INHA). Here we sought to query this impact on survival in patients undergoing resection of glioblastoma (GBM). All patients receiving elective resection of a newly diagnosed, isocitrate-dehydrogenase-1-(IDH1)-wildtype GBM under general anesthesia between January 2010 and June 2017 in the Department of Neurosurgery, Heidelberg University Hospital, were included. Patients were grouped according to the applied anesthetic technique. To adjust for potential prognostic confounders, patients were matched in a 1:2 ratio (TIVA vs. INHA), taking into account the known prognostic factors: age, extent of resection, O-6-methylguanine-DNA-methyltransferase-(MGMT)-promoter-methylation-status, pre-operative Karnofsky-performance-index and adjuvant radio- and chemotherapy. The primary endpoint was progression-free-survival (PFS) and the secondary endpoint was overall-survival (OS). In the study period, 576 patients underwent resection of a newly diagnosed, IDH-wildtype GBM. Patients with incomplete follow-up-data, on palliative treatment, having emergency or awake surgery; 54 patients remained in the TIVA-group and 417 in the INHA-group. After matching, 52 patients remained in the TIVA-group and 92 in the INHA-group. Median PFS was 6 months in both groups. The median OS was 13.5 months in the TIVA-group and 13.0 months in the INHA-group. No significant survival differences associated with the type of anesthesia were found either before or after adjustment for known prognostic factors. This retrospective study supports the notion that the current anesthetic approaches employed during the resection of IDH-wildtype GBM do not impact patient survival.

Prognostic Value of microRNA-221/2 and 17-92 Families in Primary Glioblastoma Patients Treated with Postoperative Radiotherapy.

MicroRNAs (miRs) are non-coding master regulators of transcriptome that could act as tumor suppressors (TSs) or oncogenes (oncomiRs). We aimed to systematically investigate the relevance of miRs as prognostic biomarkers in primary glioblastoma multiforme (GBM) treated with postoperative radio(chemo)therapy (PORT). For hypothesis generation, tumor miR expression by Agilent 8x15K human microRNA microarrays and survival data from 482 GBM patients of The Cancer Genome Atlas (TCGA cohort) were analyzed using Cox-PH models. Expression of candidate miRs with prognostic relevance (miR-221/222; miR-17-5p, miR-18a, miR-19b) was validated by qRT-PCR using Taqman technology on an independent validation cohort of GBM patients (n = 109) treated at Heidelberg University Hospital (HD cohort). In TCGA, 50 miRs showed significant association with survival. Among the top ranked prognostic miRs were members of the two miR families miR-221/222 and miR-17-92. Loss of miR-221/222 was correlated with improved prognosis in both cohorts (TCGA, HD) and was an independent prognostic marker in a multivariate analysis considering demographic characteristics (age, sex, Karnofsky performance index (KPI)), molecular markers (O-6-methylguanine-DNA methyltransferase (MGMT) methylation, IDH mutation status) and PORT as co-variables. The prognostic value of miR-17-92 family members was ambiguous and in part contradictory by direct comparison of the two cohorts, thus warranting further validation in larger prospective trials.

Increased Radiation-Associated T-Cell Infiltration in Recurrent IDH-Mutant Glioma.

Most gliomas are associated with a fatal prognosis and remain incurable because of their infiltrative growth. Consequently, the addition of immunotherapy to conventional therapy may improve patient outcomes. Here, we analyzed T-cell infiltration and, therefore, a major prerequisite for successful immunotherapy in a series of primary (n = 78) and recurrent (n = 66) isocitrate dehydrogenase (IDH)-mutant glioma and their changes following treatment with radio- and/or chemotherapy. After multicolor immunofluorescence staining, T cells were counted in entire tumor sections using a software-based setup. Newly diagnosed diffuse IDH-mutant gliomas displayed a median T-cell infiltration of 0.99 T cells/mm2 (range: 0-48.97 CD3+ T cells/mm2), which was about two-fold increased for CD3+, helper, and cytotoxic T cells in recurrent glioma. Furthermore, T-cell infiltration of recurrent tumors was associated with the type of adjuvant treatment of the primary tumor. Interestingly, only glioma patients solely receiving radiotherapy presented consistently with increased T-cell infiltration in their recurrent tumors. This was confirmed in a subset of 27 matched pairs. In conclusion, differences in the T-cell infiltration of primary and recurrent gliomas were demonstrated, and evidence was provided for a beneficial long-term effect on T-cell infiltration upon treatment with radiotherapy.

Impact of post-surgical freezing delay on brain tumor metabolomics.

INTRODUCTION: Translational cancer research has seen an increasing interest in metabolomic profiling to decipher tumor phenotypes. However, the impact of post-surgical freezing delays on mass spectrometric metabolomic measurements of the cancer tissue remains elusive. OBJECTIVES: To evaluate the impact of post-surgical freezing delays on cancer tissue metabolomics and to investigate changes per metabolite and per metabolic pathway. METHODS: We performed untargeted metabolomics on three cortically located and bulk-resected glioblastoma tissues that were sequentially frozen as duplicates at up to six different time delays (0-180 min, 34 samples). RESULTS: Statistical modelling revealed that 10% of the metabolome (59 of 597 metabolites) changed significantly after a 3 h delay. While carbohydrates and energy metabolites decreased, peptides and lipids increased. After a 2 h delay, these metabolites had changed by as much as 50-100%. We present the first list of metabolites in glioblastoma tissues that are sensitive to post-surgical freezing delays and offer the opportunity to define individualized fold change thresholds for future comparative metabolomic studies. CONCLUSION: More researchers should take these pre-analytical factors into consideration when analyzing metabolomic data. We present a strategy for how to work with metabolites that are sensitive to freezing delays.

Microscopic brain invasion in meningiomas previously classified as WHO grade I is not associated with patient outcome.

PURPOSE: For meningiomas, the 2016 revision of the WHO classification introduced brain invasion per se as a sufficient condition to classify as grade II. We analyzed whether meningiomas previously graded as WHO grade I differ in prognosis depending on the presence of microscopic brain invasion. METHODS: A consecutive series of patients with intracranial meningioma WHO grade I (± brain invasion) at two neurosurgical departments was analyzed retrospectively. Cox regression models on progression-free survival (PFS) and Kaplan-Meier survival estimates were performed. RESULTS: 875 adult patients were included. Histological diagnosis of brain invasion was confirmed in 28 patients. Median follow-up was 73 months. In univariate and multivariate models, gross total resection gained favorable prognostic influence for PFS (p < 0.001, HR: 0.237, CI 0.170-0.382). 170 patients with the brain/meningioma interface present in histopathological specimen were separately analyzed as a subgroup. Importantly, presence of brain invasion did not reach significance for PFS, even in the subgroup with available specimen of brain/meningioma interface (p = 0.787, HR: 0.852, CI 0.268-2.710 and p = 0.811, HR: 0.848, CI 0.222-3.246, respectively). Patients with and without brain invasion did not differ in terms of age, tumor location and extent of resection, but were more likely to receive radiotherapy (p = 0.03) of tumor remnants. However, subgroup analysis of non-irradiated tumors revealed no prognostic influence of brain invasion (p = 0.749, HR: 0.772, CI 0.158-3.767). CONCLUSIONS: In this bi-institutional series, brain invasion was frequent among meningiomas WHO grade I when brain/meningioma interface was available for histology (16.5%). However, brain invasion did not impact early recurrence.

Novel, improved grading system(s) for IDH-mutant astrocytic gliomas.

According to the 2016 World Health Organization Classification of Tumors of the Central Nervous System (2016 CNS WHO), IDH-mutant astrocytic gliomas comprised WHO grade II diffuse astrocytoma, IDH-mutant (AIIIDHmut), WHO grade III anaplastic astrocytoma, IDH-mutant (AAIIIIDHmut), and WHO grade IV glioblastoma, IDH-mutant (GBMIDHmut). Notably, IDH gene status has been made the major criterion for classification while the manner of grading has remained unchanged: it is based on histological criteria that arose from studies which antedated knowledge of the importance of IDH status in diffuse astrocytic tumor prognostic assessment. Several studies have now demonstrated that the anticipated differences in survival between the newly defined AIIIDHmut and AAIIIIDHmut have lost their significance. In contrast, GBMIDHmut still exhibits a significantly worse outcome than its lower grade IDH-mutant counterparts. To address the problem of establishing prognostically significant grading for IDH-mutant astrocytic gliomas in the IDH era, we undertook a comprehensive study that included assessment of histological and genetic approaches to prognosis in these tumors. A discovery cohort of 211 IDH-mutant astrocytic gliomas with an extended observation was subjected to histological review, image analysis, and DNA methylation studies. Tumor group-specific methylation profiles and copy number variation (CNV) profiles were established for all gliomas. Algorithms for automated CNV analysis were developed. All tumors exhibiting 1p/19q codeletion were excluded from the series. We developed algorithms for grading, based on molecular, morphological and clinical data. Performance of these algorithms was compared with that of WHO grading. Three independent cohorts of 108, 154 and 224 IDH-mutant astrocytic gliomas were used to validate this approach. In the discovery cohort several molecular and clinical parameters were of prognostic relevance. Most relevant for overall survival (OS) was CDKN2A/B homozygous deletion. Other parameters with major influence were necrosis and the total number of CNV. Proliferation as assessed by mitotic count, which is a key parameter in 2016 CNS WHO grading, was of only minor influence. Employing the parameters most relevant for OS in our discovery set, we developed two models for grading these tumors. These models performed significantly better than WHO grading in both the discovery and the validation sets. Our novel algorithms for grading IDH-mutant astrocytic gliomas overcome the challenges caused by introduction of IDH status into the WHO classification of diffuse astrocytic tumors. We propose that these revised approaches be used for grading of these tumors and incorporated into future WHO criteria.

DNA methylation-based classification and grading system for meningioma: a multicentre, retrospective analysis.

BACKGROUND: The WHO classification of brain tumours describes 15 subtypes of meningioma. Nine of these subtypes are allotted to WHO grade I, and three each to grade II and grade III. Grading is based solely on histology, with an absence of molecular markers. Although the existing classification and grading approach is of prognostic value, it harbours shortcomings such as ill-defined parameters for subtypes and grading criteria prone to arbitrary judgment. In this study, we aimed for a comprehensive characterisation of the entire molecular genetic landscape of meningioma to identify biologically and clinically relevant subgroups. METHODS: In this multicentre, retrospective analysis, we investigated genome-wide DNA methylation patterns of meningiomas from ten European academic neuro-oncology centres to identify distinct methylation classes of meningiomas. The methylation classes were further characterised by DNA copy number analysis, mutational profiling, and RNA sequencing. Methylation classes were analysed for progression-free survival outcomes by the Kaplan-Meier method. The DNA methylation-based and WHO classification schema were compared using the Brier prediction score, analysed in an independent cohort with WHO grading, progression-free survival, and disease-specific survival data available, collected at the Medical University Vienna (Vienna, Austria), assessing methylation patterns with an alternative methylation chip. FINDINGS: We retrospectively collected 497 meningiomas along with 309 samples of other extra-axial skull tumours that might histologically mimic meningioma variants. Unsupervised clustering of DNA methylation data clearly segregated all meningiomas from other skull tumours. We generated genome-wide DNA methylation profiles from all 497 meningioma samples. DNA methylation profiling distinguished six distinct clinically relevant methylation classes associated with typical mutational, cytogenetic, and gene expression patterns. Compared with WHO grading, classification by individual and combined methylation classes more accurately identifies patients at high risk of disease progression in tumours with WHO grade I histology, and patients at lower risk of recurrence among WHO grade II tumours (p=0·0096) from the Brier prediction test). We validated this finding in our independent cohort of 140 patients with meningioma. INTERPRETATION: DNA methylation-based meningioma classification captures clinically more homogenous groups and has a higher power for predicting tumour recurrence and prognosis than the WHO classification. The approach presented here is potentially very useful for stratifying meningioma patients to observation-only or adjuvant treatment groups. We consider methylation-based tumour classification highly relevant for the future diagnosis and treatment of meningioma. FUNDING: German Cancer Aid, Else Kröner-Fresenius Foundation, and DKFZ/Heidelberg Institute of Personalized Oncology/Precision Oncology Program.

Identification of T cell target antigens in glioblastoma stem-like cells using an integrated proteomics-based approach in patient specimens.

Glioblastoma (GBM) is a highly aggressive brain tumor and still remains incurable. Among others, an immature subpopulation of self-renewing and therapy-resistant tumor cells-often referred to as glioblastoma stem-like cells (GSCs)-has been shown to contribute to disease recurrence. To target these cells personalized immunotherapy has gained a lot of interest, e.g. by reactivating pre-existing anti-tumor immune responses against GSC antigens. To identify T cell targets commonly presented by GSCs and their differentiated counterpart, we used a proteomics-based separation of GSC proteins in combination with a T cell activation assay. Altogether, 713 proteins were identified by LC-ESI-MS/MS mass spectrometry. After a thorough filtering process, 32 proteins were chosen for further analyses. Immunogenicity of corresponding peptides was tested ex vivo. A considerable number of these antigens induced T cell responses in GBM patients but not in healthy donors. Moreover, most of them were overexpressed in primary GBM and also highly expressed in recurrent GBM tissues. Interestingly, expression of the most frequent T cell target antigens could also be confirmed in quiescent, slow-cycling GSCs isolated in high purity by the DEPArray technology. Finally, for a subset of these T cell target antigens, an association between expression levels and higher T cell infiltration as well as an increased expression of positive immune modulators was observed. In summary, we identified novel immunogenic proteins, which frequently induce tumor-specific T cell responses in GBM patients and were also detected in vitro in therapy-resistant quiescent, slow-cycling GSCs. Stable expression of these T cell targets in primary and recurrent GBM support their suitability for future clinical use.

LOC283731 promoter hypermethylation prognosticates survival after radiochemotherapy in IDH1 wild-type glioblastoma patients.

MGMT promoter methylation status is currently the only established molecular prognosticator in IDH wild-type glioblastoma multiforme (GBM). Therefore, we aimed to discover novel therapy-associated epigenetic biomarkers. After enrichment for hypermethylated fractions using methyl-CpG-immunoprecipitation (MCIp), we performed global DNA methylation profiling for 14 long-term (LTS; >36 months) and 15 short-term (STS; 6-10 months) surviving GBM patients. Even after exclusion of the G-CIMP phenotype, we observed marked differences between the LTS and STS methylome. A total of 1,247 probes in 706 genes were hypermethylated in LTS and 463 probes in 305 genes were found to be hypermethylated in STS patients (p values < 0.05, log2 fold change ± 0.5). We identified 13 differentially methylated regions (DMRs) with a minimum of four differentially methylated probes per gene. Indeed, we were able to validate a subset of these DMRs through a second, independent method (MassARRAY) in our LTS/STS training set (ADCY1, GPC3, LOC283731/ISLR2). These DMRs were further assessed for their prognostic capability in an independent validation cohort (n = 62) of non-G-CIMP GBMs from the TCGA. Hypermethylation of multiple CpGs mapping to the promoter region of LOC283731 correlated with improved patient outcome (p = 0.03). The prognostic performance of LOC283731 promoter hypermethylation was confirmed in a third independent study cohort (n = 89), and was independent of gender, performance (KPS) and MGMT status (p = 0.0485, HR = 0.63). Intriguingly, the prediction was most pronounced in younger GBM patients (<60 years). In conclusion, we provide compelling evidence that promoter methylation status of this novel gene is a prognostic biomarker in IDH1 wild-type/non-G-CIMP GBMs.