Impact of focal cortical dysplasia Type IIIa on seizure outcome following anterior mesial temporal lobe resection for the treatment of epilepsy

OBJECTIVE

Temporal lobe epilepsy (TLE) is the most common type of pharmacoresistant focal epilepsy, for which anterior mesial temporal lobe resection (AMTLR) is a treatment option. Focal cortical dysplasia Type IIIa (FCD IIIa), a developmental lesion resulting from defects in neuronal formation and migration into the temporal pole (FCD I) combined with hippocampal sclerosis (HS), can be a neuropathological finding. In this study, the authors investigate the impact of FCD IIIa on seizure outcome in patients with TLE who underwent AMTLR.

METHODS

The authors performed a retrospective analysis of all patients with TLE who underwent AMTLR at their institution between June 2011 and April 2014. Histopathological analysis was used to determine whether patients had HS together with FCD I (FCD IIIa) or HS alone. The groups were compared with regard to age, sex, years of epilepsy, and seizure outcome using the Engel classification.

RESULTS

A total of 51 patients with TLE underwent AMTLR at the authors’ institution. FCD IIIa was diagnosed in 13 cases. The patients experienced seizures for a mean duration of 31.1 years. The mean length of follow-up after the procedure was 18 months. All patients with FCD IIIa had a favorable seizure outcome (Engel Class I or II) compared with 71% of the patients with no pathological findings in the temporal pole (p < 0.01).

CONCLUSIONS

Patients with histopathologically proven FCD IIIa had a significantly better seizure outcome after AMTLR than patients with HS alone. Further effort should be made during presurgical evaluation to detect FCD IIIa so that the most suitable resection technique can be chosen and postoperative seizure outcome can be predicted for patient counseling.

The natural HLA ligandome of glioblastoma stem-like cells: antigen discovery for T cell-based immunotherapy

Glioblastoma is the most frequent malignant primary brain tumor. In a hierarchical tumor model, glioblastoma stem-like cells (GSC) play a major role in tumor initiation and maintenance as well as in therapy resistance and recurrence. Thus, targeting this cellular subset may be key to effective immunotherapy. Here, we present a mass spectrometry-based analysis of HLA-presented peptidomes of GSC and glioblastoma patient specimens. Based on the analysis of patient samples (n = 9) and GSC (n = 3), we performed comparative HLA peptidome profiling against a dataset of normal human tissues. Using this immunopeptidome-centric approach we could clearly delineate a subset of naturally presented, GSC-associated HLA ligands, which might serve as highly specific targets for T cell-based immunotherapy. In total, we identified 17 antigens represented by 41 different HLA ligands showing natural and exclusive presentation both on GSC and patient samples. Importantly, in vitro immunogenicity and antigen-specific target cell killing assays suggest these peptides to be epitopes of functional CD8+ T cell responses, thus rendering them prime candidates for antigen-specific immunotherapy of glioblastoma.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

DNA methylation-based classification of central nervous system tumours

Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging-with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.

Immune evasion mediated by PD-L1 on glioblastoma-derived extracellular vesicles

Binding of programmed death ligand-1 (PD-L1) to programmed cell death protein-1 (PD1) leads to cancer immune evasion via inhibition of T cell function. One of the defining characteristics of glioblastoma, a universally fatal brain cancer, is its profound local and systemic immunosuppression. Glioblastoma has also been shown to generate extracellular vesicles (EVs), which may play an important role in tumor progression. We thus hypothesized that glioblastoma EVs may be important mediators of immunosuppression and that PD-L1 could play a role. We show that glioblastoma EVs block T cell activation and proliferation in response to T cell receptor stimulation. PD-L1 was expressed on the surface of some, but not of all, glioblastoma-derived EVs, with the potential to directly bind to PD1. An anti-PD1 receptor blocking antibody significantly reversed the EV-mediated blockade of T cell activation but only when PD-L1 was present on EVs. When glioblastoma PD-L1 was up-regulated by IFN-γ, EVs also showed some PD-L1-dependent inhibition of T cell activation. PD-L1 expression correlated with the mesenchymal transcriptome profile and was anatomically localized in the perinecrotic and pseudopalisading niche of human glioblastoma specimens. PD-L1 DNA was present in circulating EVs from glioblastoma patients where it correlated with tumor volumes of up to 60 cm³. These results suggest that PD-L1 on EVs may be another mechanism for glioblastoma to suppress antitumor immunity and support the potential of EVs as biomarkers in tumor patients.

Intracranial pressure in patients undergoing decompressive craniectomy: new perspective on thresholds

OBJECTIVE

Decompressive craniectomy (DC) is an established part of treatment in patients suffering from malignant infarction of the middle cerebral artery (MCA) or traumatic brain injury (TBI). However, no clear evidence for intracranial pressure (ICP)-guided therapy after DC exists. The lack of this evidence might be due to the frequently used, but simplified threshold for ICP of 20 mm Hg, which determines further therapy. Therefore, the objective of this study was to evaluate this threshold's accuracy and to investigate the course of ICP values with respect to neurological outcome.

METHODS

Data on clinical characteristics and parameters of the ICP course on the intensive care unit were collected retrospectively in 102 patients who underwent DC between December 2007 and April 2014 at the authors' institution. The postoperative ICP course in the first 168 hours was recorded and analyzed. From these findings, ICP thresholds discriminating favorable from unfavorable outcome were calculated using conditional inference tree analysis. Additionally, survival analysis was performed using the Kaplan-Meier method. Prognostic factors were assessed via univariate analysis and multivariate logistic regression. Favorable outcome was defined as a score of 0–4 on the modified Rankin Scale.

RESULTS

Multivariate logistic regression revealed that anisocoria, diagnosis, and ICP values differed significantly between the outcome groups. ICP values in the favorable and unfavorable outcome groups differed significantly (p < 0.001), while the mean ICP of both groups lay below the limit of 20 mm Hg (17.5 and 11.5 mm Hg, respectively). These findings were reproduced when analyzing the underlying pathologies of TBI and MCA infarction separately. Based on these findings, optimized time-dependent threshold values were calculated and found to be between 10 and 17 mm Hg. These values significantly distinguished favorable from unfavorable outcome and predicted 30-day mortality (p < 0.001).

CONCLUSIONS

This study systematically evaluated ICP levels in a long-term analysis after DC and provides new, surprisingly low, time-dependent ICP thresholds for these patients. Future trials investigating the benefit of ICP-guided therapy should take these thresholds into consideration and validate them in further patient cohorts.

PTEN mediates the cross talk between breast and glial cells in brain metastases leading to rapid disease progression

Despite improvement of therapeutic treatments for breast cancer, the development of brain metastases has become a major limitation to life expectancy for many patients. Brain metastases show very commonly alterations in EGFR and HER2 driven pathways, of which PTEN is an important regulator. Here, we analyzed PTEN expression in 111 tissue samples of breast cancer brain metastases (BCBM). Loss of PTEN was found in a substantial proportion of BCBM samples (48.6%) and was significantly associated with triple-negative breast cancer (67.5%, p = 0.001) and a shorter survival time after surgical resection of brain metastases (p = 0.048). Overexpression of PTEN in brain-seeking MDA-MB-231 BR cells in vitro reduced activation of the AKT pathway, notably by suppression of Akt1 kinase activity. Furthermore, the migration of MDA-MB-231 BR cells in vitro was promoted by co-culturing with both astrocytes and microglial cells. Interestingly, when PTEN was overexpressed the migration was significantly inhibited. Moreover, in an ex vivo organotypic brain slice model, PTEN overexpression reduced invasion of tumor cells. This was accompanied by reduced astrocyte activation that was mediated by autocrine and paracrine activation of GM-CSF/ CSF2RA and AKT/ PTEN pathways. In conclusion, loss of PTEN is frequently detected in triple-negative BCBM patients and associated with poor prognosis. The findings of our functional studies suggest that PTEN loss promotes a feedback loop between tumor cells and glial cells, which might contribute to disease progression.

Prognostic relevance of miRNA-155 methylation in anaplastic glioma

The outcome of patients with anaplastic gliomas varies considerably depending on single molecular markers, such as mutations of the isocitrate dehydrogenase (IDH) genes, as well as molecular classifications based on epigenetic or genetic profiles. Remarkably, 98% of the RNA within a cell is not translated into proteins. Of those, especially microRNAs (miRNAs) have been shown not only to have a major influence on physiologic processes but also to be deregulated and prognostic in malignancies.To find novel survival markers and treatment options we performed unbiased DNA methylation screens that revealed 12 putative miRNA promoter regions with differential DNA methylation in anaplastic gliomas. Methylation of these candidate regions was validated in different independent patient cohorts revealing a set of miRNA promoter regions with prognostic relevance across data sets. Of those, miR-155 promoter methylation and miR-155 expression were negatively correlated and especially the methylation showed superior correlation with patient survival compared to established biomarkers.Functional examinations in malignant glioma cells further cemented the relevance of miR-155 for tumor cell viability with transient and stable modifications indicating an onco-miRNA activity. MiR-155 also conferred resistance towards alkylating temozolomide and radiotherapy as consequence of nuclear factor (NF)κB activation.Preconditioning glioma cells with an NFκB inhibitor reduced therapy resistance of miR-155 overexpressing cells. These cells resembled tumors with a low methylation of the miR-155 promoter and thus mir-155 or NFκB inhibition may provide treatment options with a special focus on patients with IDH wild type tumors.

Transcriptomic analysis of aggressive meningiomas identifies PTTG1 and LEPR as prognostic biomarkers independent of WHO grade

Meningiomas are frequent central nervous system tumors. Although most meningiomas are benign (WHO grade I) and curable by surgery, WHO grade II and III tumors remain therapeutically challenging due to frequent recurrence. Interestingly, relapse also occurs in some WHO grade I meningiomas. Hence, we investigated the transcriptional features defining aggressive (recurrent, malignantly progressing or WHO grade III) meningiomas in 144 cases. Meningiomas were categorized into non-recurrent (NR), recurrent (R), and tumors undergoing malignant progression (M) in addition to their WHO grade. Unsupervised transcriptomic analysis in 62 meningiomas revealed transcriptional profiles lining up according to WHO grade and clinical subgroup. Notably aggressive subgroups (R+M tumors and WHO grade III) shared a large set of differentially expressed genes (n=332; p<0.01, FC>1.25). In an independent multicenter validation set (n=82), differential expression of 10 genes between WHO grades was confirmed. Additionally, among WHO grade I tumors differential expression between NR and aggressive R+M tumors was affirmed for PTTG1, AURKB, ECT2, UBE2C and PRC1, while MN1 and LEPR discriminated between NR and R+M WHO grade II tumors. Univariate survival analysis revealed a significant association with progression-free survival for PTTG1, LEPR, MN1, ECT2, PRC1, COX10, UBE2C expression, while multivariate analysis identified a prediction for PTTG1 and LEPR mRNA expression independent of gender, WHO grade and extent of resection. Finally, stainings of PTTG1 and LEPR confirmed malignancy-associated protein expression changes. In conclusion, based on the so far largest study sample of WHO grade III and recurrent meningiomas we report a comprehensive transcriptional landscape and two prognostic markers.

Rare ADAR and RNASEH2B variants and a type I interferon signature in glioma and prostate carcinoma risk and tumorigenesis

In search of novel germline alterations predisposing to tumors, in particular to gliomas, we studied a family with two brothers affected by anaplastic gliomas, and their father and paternal great-uncle diagnosed with prostate carcinoma. In this family, whole-exome sequencing yielded rare, simultaneously heterozygous variants in the Aicardi-Goutières syndrome (AGS) genes ADAR and RNASEH2B co-segregating with the tumor phenotype. AGS is a genetically induced inflammatory disease particularly of the brain, which has not been associated with a consistently increased cancer risk to date. By targeted sequencing, we identified novel ADAR and RNASEH2B variants, and a 3- to 17-fold frequency increase of the AGS mutations ADAR,c.577C>G;p.(P193A) and RNASEH2B,c.529G>A;p.(A177T) in the germline of familial glioma patients as well as in test and validation cohorts of glioblastomas and prostate carcinomas versus ethnicity-matched controls, whereby rare RNASEH2B variants were significantly more frequent in familial glioma patients. Tumors with ADAR or RNASEH2B variants recapitulated features of AGS, such as calcification and increased type I interferon expression. Patients carrying ADAR or RNASEH2B variants showed upregulation of interferon-stimulated gene (ISG) transcripts in peripheral blood as seen in AGS. An increased ISG expression was also induced by ADAR and RNASEH2B variants in tumor cells and was blocked by the JAK inhibitor Ruxolitinib. Our data implicate rare variants in the AGS genes ADAR and RNASEH2B and a type I interferon signature in glioma and prostate carcinoma risk and tumorigenesis, consistent with a genetic basis underlying inflammation-driven malignant transformation in glioma and prostate carcinoma development.

Somatosensory evoked potentials in patients with high-grade aneurysmal subarachnoid hemorrhage

OBJECTIVE The aim of this prospective study was to investigate the value of somatosensory evoked potentials (SEPs) in predicting outcome in patients with high-grade aneurysmal subarachnoid hemorrhage (SAH). METHODS Between January 2013 and January 2015, 48 patients with high-grade SAH (Hunt and Hess Grade III, IV, or V) who were admitted within 3 days after hemorrhage were enrolled in the study. Right and left median and tibial nerve SEPs were recorded on Day 3 after hemorrhage and recorded again 2 weeks later. Glasgow Outcome Scale (GOS) scores were determined 6 months after hemorrhage and dichotomized as poor (Scores 1-3) or good (Scores 4-5). Results of SEP measurements were dichotomized (present or missing cortical responses or normal or prolonged latencies) for each nerve and side. These variables were summed and tested using logistic regression and a receiver operating characteristic curve to assess the value of SEPs in predicting long-term outcome. RESULTS At the 6-month follow-up visit, 29 (60.4%) patients had a good outcome, and 19 (39.6%) had a poor outcome. The first SEP measurement did not correlate with clinical outcome (area under the curve [AUC] 0.69, p = 0.52). At the second measurement of median nerve SEPs, all patients with a good outcome had cortical responses present bilaterally, and none of them had bilateral prolonged latencies (p = 0.014 and 0.003, respectively). In tibial nerve SEPs, 7.7% of the patients with a good GOS score had one or more missing cortical responses, and bilateral prolonged latencies were found in 23% (p = 0.001 and 0.034, respectively). The second measurement correlated with the outcome regarding each of the median and tibial nerve SEPs and the combination of both (AUC 0.75 [p = 0.010], 0.793 [p = 0.003], and 0.81 [p = 0.001], respectively). CONCLUSIONS Early SEP measurement after SAH did not correlate with clinical outcome, but measurement of median and tibial nerve SEPs 2 weeks after a hemorrhage did predict long-term outcome in patients with high-grade SAH.

Maternal Aneurysmal Subarachnoid Hemorrhage During Pregnancy as an Interdisciplinary Task

Maternal aneurysmal subarachnoid hemorrhage (aSAH) during pregnancy presents a challenge regarding treatment and management. Due to the limited number of cases there are no treatment guidelines available. Thus, treatment is usually done on a case-by-case basis. Here we report on four cases of aSAH during pregnancy, describing the different management strategies and suggesting a possible treatment algorithm. Patients treated between 2003 and 2013 in our center were included in this retrospective study. Clinical data focused on time management concerning gestation week (GW), microsurgical or endovascular treatment, and outcome of the patients and the fetuses. Results were compared to the present literature on this issue. Mean age was 30.8 years, initial Hunt & Hess (H&H) grade ranged from III to V. All patients suffered from aSAH during the 3rd trimester of pregnancy. In the four cases, two emergency Caesarean sections (CS) were performed. Two aneurysms were occluded by microsurgical clipping and one was treated endovascularly. One patient died before definitive treatment of the aneurysm could be achieved, whereas fetal mortality was 0%. The mean follow-up was 83 months. aSAH during pregnancy needs individualized interdisciplinary management. Efforts must focus on the mother so that a delay in the best available treatment for the pregnant patient is avoided. Therefore treatment modality should be primarily determined by the aneurysm itself. However, timing in terms of delivery of the fetus and aneurysm treatment is a crucial point.

Prognostic Value of Early S100 Calcium Binding Protein B and Neuron-Specific Enolase in Patients with Poor-Grade Aneurysmal Subarachnoid Hemorrhage: A Pilot Study

BACKGROUND

This prospective study was undertaken to investigate the value of early S100 calcium binding protein B (S100B) and neuron-specific enolase (NSE) in prognosticating outcome in patients with poor-grade aneurysmal subarachnoid hemorrhage and to develop a statistical model and cutoff values for clinical practice.

METHODS

Between 2012 and 2014, patients with poor-grade subarachnoid hemorrhage (Hunt and Hess grade 3-5) who were admitted within 24 hours after hemorrhage were prospectively enrolled. Serum NSE and S100B levels were assayed once daily during the first 3 days after hemorrhage. Patient characteristics, Glasgow Coma Scale score, Hunt and Hess grade, and Fisher grade at admission were recorded. Glasgow Outcome Scale (GOS) score was obtained at 6 months and dichotomized as poor (score 1-3) or good (score 4-5). Logistic regression and receiver operating characteristic curve were used to assess the value of S100B and NSE in predicting outcome, and cutoff values were calculated using conditional interference trees.

RESULTS

The study included 52 patients. Hunt and Hess grade was 3 in 23 patients, 4 in 15 patients, and 5 in 14 patients. S100B range was 0.07-5.62 μg/L (mean 0.87 μg/L ± 1.06). NSE range was 5.7-94.2 μg/L (mean 16.1 μg/L ± 10.5). At 6-month follow-up, 23 patients (44.2%) had a poor outcome, and 29 patients (55.8%) had a good outcome. Both S100B at day 1 (P = 0.004; cutoff 0.202 μg/L) and NSE at day 1 (P = 0.047; cutoff 9.4 μg/L) predicted good outcome with a specificity of 100%. The specificity of mean S100B in detecting patients with poor outcome reached 100% (P = 0.003) when combined with mean NSE levels.

CONCLUSIONS

S100B and NSE measured during the first 3 days after hemorrhage showed, separately and combined, a significant predictive value in prognosticating clinical outcome in patients with poor-grade subarachnoid hemorrhage. A multicenter study with a large patient cohort is necessary to validate the above-mentioned cutoff values for clinical practice.

Body Mass Index >35 as Independent Predictor of Mortality in Severe Traumatic Brain Injury

OBJECTIVE

Severe traumatic brain injury (TBI) has a major influence on polytrauma outcome. The aim of this study was to evaluate the impact of body mass index (BMI) on mortality and early neurologic outcome in patients suffering from severe TBI with a special focus on obesity classes II and III (BMI ≥35).

METHODS

A retrospective cohort analysis of patients suffering from a leading, at least severe TBI and registered in the TraumaRegister DGU was conducted. Patients alive on admission with full status documentation on Glasgow Coma Scale, height, and weight were classified into 4 BMI subgroups. Early neurologic outcome was classified using the Glasgow Outcome Scale.

RESULTS

A total of 1634 patients met the inclusion criteria. Lowest mortality was documented for BMI group 1 (15.2%, BMI 25.0-29.9918.5). Highest mortality was found in BMI group 5 (25.6%, BMI ≥35). BMI ≥35 was an independent predictor of mortality with an odds ratio of 3.15 (95% confidence interval [1.06-9.36], P = 0.039). Further independent mortality predictors were >65 years of age, a Glasgow Coma Scale of ≤13, an Abbreviated Injury Scale_head ≥5, prehospital cardiopulmonary resuscitation, and a prehospital blood pressure of <90 mm Hg. In terms of good early neurologic outcomes, no differences were recorded between the BMI groups (range 59.0%-62.6%, P = 0.087).

CONCLUSIONS

In this study a BMI ≥35 is an independent predictor of mortality and is associated with an inferior early functional neurologic outcome.

Circulating Tumour Cell Release after Cement Augmentation of Vertebral Metastases

Cement augmentation via percutaneous vertebroplasty or kyphoplasty for treatment of spinal metastasis is a well-established treatment option. We assessed whether elevated intrametastatic pressure during cement augmentation results in an increased dissemination of tumour cells into the vascular circulation. We prospectively collected blood from patients with osteolytic spinal column metastases and analysed the prevalence of circulating tumour cells (CTCs) at three time-points: preoperatively, 20 minutes after cement augmentation, and 3–5 days postoperatively. Enrolling 21 patients, including 13 breast- (61.9%), 5 lung- (23.8%), and one (4.8%) colorectal-, renal-, and prostate-carcinoma patient each, we demonstrate a significant 1.8-fold increase of EpCAM+/K+ CTCs in samples taken 20 minutes post-cement augmentation (P < 0.0001). Despite increased mechanical CTC dissemination due to cement augmentation, follow-up blood draws demonstrated that no long-term increase of CTCs was present. Array-CGH analysis revealed a specific profile of the CTC collected 20 minutes after cement augmentation. This is the first study to report that peripheral CTCs are temporarily increased due to vertebral cement augmentation procedures. Our findings provide a rationale for the development of new prophylactic strategies to reduce the increased release of CTC after cement augmentation of osteolytic spinal metastases.

Keyhole approaches to intradural pathologies

OBJECTIVE

Spinal tumors account for 2%–4% of all tumors of the central nervous system and can be intramedullary, intradural extramedullary, or extradural. In the past, wide approaches were used to obtain safe access to these tumors, as complete resection is the goal in treating most tumor entities. To reduce surgical complications due to large skin incisions and destabilizing laminectomies, minimally invasive approaches were established. In this study, the authors share their experience with mini-open approaches to intradural tumor pathologies.

METHODS

The authors retrospectively reviewed cases involving patients with intramedullary and intradural extramedullary lesions treated between 2009 and 2016. They present their surgical mini-open approach to the spinal cord as well as unique characteristics, key steps, and postsurgical complications for specific tumor subgroups (meningioma, neuroma, and intramedullary tumors).

RESULTS

A total of 245 intradural tumors were surgically treated during the study period. Of these lesions, 151 were intradural extramedullary meningiomas (n = 79) or neuromas (n = 72). Nine (12.5%) of the neuromas were dumbbell neuromas. Ninety-four tumors were intramedullary. The mean age of the patients was 51.4 years, and 53.9% were female. The mean duration of follow-up was 46.0 months.

All meningiomas and neuromas could be resected using a mini-open keyhole approach, but only 5.3% of the intramedullary lesions could be accessed using this technique. Of the 94 patients with intramedullary tumors, 76.6% required a laminotomy, 7.4% required a hemilaminectomy, and 10.6% required a 2-level laminectomy. Only 2 of the patients with intramedullary tumors needed stabilization for progressive cervical kyphosis during follow-up. None of the other patients developed spinal instability after undergoing surgery via the mini-open (keyhole/interlaminar) approach. There were significantly more surgery-associated complications in the large exposure group than in the patients treated with the mini-open approach (19.1% vs 9.6%, p < 0.01).

CONCLUSIONS

Intradural extramedullary and in selected cases intramedullary pathologies may safely be resected using a mini-open interlaminar approach. Avoiding laminectomy, laminotomy, and even hemilaminectomy preserves spinal stability and significantly reduces comorbidities, while still allowing for complete resection of these tumors.

Adverse events in deep brain stimulation: A retrospective long-term analysis of neurological, psychiatric and other occurrences

Background and objective

The extent to which deep brain stimulation (DBS) can improve quality of life may be perceived as a permanent trade-off between neurological improvements and complications of therapy, comorbidities, and disease progression.

Patients and methods

We retrospectively investigated 123 consecutive and non-preselected patients. Indications for DBS surgery were Parkinson's disease (82), dystonia (18), tremor of different etiology (21), Huntington's disease (1) and Gilles de la Tourette syndrome (1). AEs were defined as any untoward clinical occurrence, sign or patient complaint or unintended disease if related or unrelated to the surgical procedures, implanted devices or ongoing DBS therapy.

Results

Over a mean/median follow-up period of 4.7 years (578 patient-years) 433 AEs were recorded in 106 of 123 patients (86.2%). There was no mortality or persistent morbidity from the surgical procedure. All serious adverse events (SAEs) that occurred within 4 weeks of surgery were reversible. Neurological AEs (193 in 85 patients) and psychiatric AEs (78 in 48 patients) were documented most frequently. AEs in 4 patients (suicide under GPI stimulation, weight gain >20 kg, impairment of gait and speech, cognitive decline >2 years following surgery) were severe or worse, at least possibly related to DBS and non reversible. In PD 23.1% of the STN-stimulated patients experienced non-reversible (or unknown reversibility) AEs that were at least possibly related to DBS in the form of impaired speech or gait, depression, weight gain, cognitive disturbances or urinary incontinence (severity was mild or moderate in 15 of 18 patients). Age and Hoehn&Yahr stage of STN-simulated PD patients, but not preoperative motor impairment or response to levodopa, showed a weak correlation (r = 0.24 and 0.22, respectively) with the number of AEs.

Conclusions

DBS-related AEs that were severe or worse and non-reversible were only observed in PD (4 of 82 patients; 4.9%), but not in other diseases. PD patients exhibited a significant risk for non-severe AEs most of which also represented preexisting and progressive axial and non-motor symptoms of PD. Mild gait and/or speech disturbances were rather frequent complaints under VIM stimulation. GPI stimulation for dystonia could be applied with negligible DBS-related side effects.

Irreversible Total Loss of Brain Function and Organ Donation in Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening disease with an often fatal clinical course leading to irreversible loss of brain function (ILBF) (i.e., brain death). The purpose of this study was to assess the prevalence and characteristics of patients with aSAH who became organ donors after diagnosis of ILBF.

METHODS

Anonymized clinical data sets of 395 patients treated for aSAH at a university medical center from January 2011 to December 2016 were retrospectively analyzed. Prevalence of consent for organ donation and clinical characteristics, including parameters for diagnosis of irreversible loss of brain function, were assessed.

RESULTS

After initial admission to the intensive care unit, 18.0% of patients (n = 71) died (Glasgow Outcome Scale score 1). Intracerebral hemorrhage occurred in 42.3% of patients who died, aneurysmal rebleeding occurred in 19.7%, and intraventricular hemorrhage occurred in 87.3%. In 50.7% of patients who died (n = 36), ILBF was diagnosed, and 32.4% (n = 23) of these patients became organ donors. In 55.6%, additional diagnostic electroencephalography was performed. Male patients significantly more often became organ donors than female patients (P = 0.008). ILBF with subsequent organ donation was predominantly seen in patients <60 years old. A total 85 of organs were explanted for donation, including 42 kidneys, 21 livers, 3 pancreas, 11 hearts and 8 lungs.

CONCLUSIONS

ILBF in the setting of fatal aSAH is a prevalent diagnosis with complex demands for neurointensive care physicians. We demonstrated the clinical characteristics and epidemiologic factors of patients with aSAH converting to organ donors.

Pituicytoma-An outlook on possible targeted therapies

INTRODUCTION

Pituicytoma is a rare neoplasm of the sella region. Tumor resection is the primary treatment option, but remains subtotal due to excessive bleeding in many cases. The search for alternative or additional treatment regimens is necessary.

AIMS

We aimed to determine the receptor expression of pituicytoma to find alternatives or supplements to surgical therapy in the use of targeted therapies.

METHODS

Pituicytoma samples were collected from three institutions between 2006 and 2015 and were stained for vascular endothelial growth factors (VEGF), thyroid transcription factor (TTF1), and somatostatin receptors (SSTR 2/3/5). The stains were classified from 0=no staining to +++=strong staining. A complementary retrospective analysis of the patient charts regarding sex, age, and primary symptoms, pituitary function, and perioperative complications was performed.

RESULTS

Ten samples were analyzed; mean patient age was 57.8 years SD 16.3 years. Seven samples were acquired from male patients (one relapse) and three from female. All tumors stained strongly positive (+++) for VEGF-R. Six samples stained positive for TTF1. As for somatostatin receptors, three samples were slightly positive for SSTR 2; seven were negative. SSTR 3 was + in one, three were ++, three were +++, and three were 0. SSTR 5 stained +++ in 1, ++ in 5, + in 1, and 0 in three patients.

CONCLUSIONS

Pituicytomas were generally positive for VEGFR and showed regular expression of SSTR 3 and 5 indicating a possible treatment option through targeted therapies in cases where resection remains insufficient. Further research is necessary as to whether tumor growth can be inhibited using these pathways.

Clinical and molecular subgroups of ependymoma in adulthood: An analysis of the German Glioma Network

2038

Background: Ependymoma is a subtype of glioma that is rare in adults. Its classification has remained entirely morphological until recently, and surgery and radiotherapy remain the mainstays of treatment. Here we characterized DNA methylation profiles and their clinical correlates in the prospectively assembled cohort of the German Glioma Network. Methods: The GGN cohort was screened for patients diagnosed with myxopapillary ependymoma, subependymoma, classic ependymoma and anaplastic ependymoma for whom clinical data and remaining tumor tissue were available. Tumors were subjected to DNA methylation profiling using the Illumina Infinium HumanMethylation450 BeadChip platform. Molecular data were correlated with morphological tumor and clinical patient characteristics. Results: One hundred and twenty-two ependymoma patients with available tumor tissue were identified. Each adult tumor could be assigned to one of the previously defined methylation classes of ependymoma. Molecular entities of ependymal brain tumors display distinct copy-number variations. PF-EPN-B and ST-EPN-RELA tumors tend to have a worse prognosis than other ependymal subtypes in adults. Conclusions: Molecular classification of adult ependymal methylation subclasses should be implemented in routine diagnostics. Patients with PF-EPN-B and ST-EPN-RELA subtypes might benefit from early treatment beyond surgery.

Clinical and molecular features associated with long-term survival of elderly patients with glioblastoma

2013

Background: Glioblastomas in elderly patients are associated with particularly poor outcome, with only few patients demonstrating long-term survival (LTS). Methods: To better characterize clinical and molecular correlates of LTS in elderly glioblastoma patients, we searched the German Glioma Network (GGN) database for patients aged 71 years or more with histological confirmation of glioblastoma and survival of at least two years after diagnosis. Results: Of 2071 glioblastoma patients enrolled in the GGN from 2004-2012, 425 patients were aged 71 years or more; of these, 27 patients (6.4%) survived for 2 years or more (median survival: 37.1 months, 95% confidence interval: 30.0-44.2 months). A comparison of these 27 patients with the 398 patients who survived shorter than 2 years (median survival: 6.2, 95% confidence interval: 5.2-7.2 months) revealed more intensive up-front treatment and a trend towards higher initial Karnofsky performance score as distinguishing clinical factors. Molecular analyses additionally showed more frequent O6-methylguanine-DNA methyltransferase ( MGMT) promoter methylation in the LTS patients. Isocitrate dehydrogenase (IDH) mutation was restricted to single patients and the frequency of telomerase reverse transcriptase ( TERT) promoter mutation did not differ between groups. Genome-wide DNA copy number and methylation profiling using 450k microarray analysis performed for 16 LTS patients and 40 control patients revealed limited differential DNA methylation and no specific copy number profiles linked to LTS. Conclusions: Collectively, our findings confirm that LTS is rare in elderly patients with glioblastoma and that clinical and tumor-associated molecular factors linked to LTS resemble those in standard age patients, except for less common IDH mutation.

European Association for Neuro-Oncology (EANO) guideline on the diagnosis and treatment of adult astrocytic and oligodendroglial gliomas

The European Association for Neuro-Oncology guideline provides recommendations for the clinical care of adult patients with astrocytic and oligodendroglial gliomas, including glioblastomas. The guideline is based on the 2016 WHO classification of tumours of the central nervous system and on scientific developments since the 2014 guideline. The recommendations focus on pathological and radiological diagnostics, and the main treatment modalities of surgery, radiotherapy, and pharmacotherapy. In this guideline we have also integrated the results from contemporary clinical trials that have changed clinical practice. The guideline aims to provide guidance for diagnostic and management decisions, while limiting unnecessary treatments and costs. The recommendations are a resource for professionals involved in the management of patients with glioma, for patients and caregivers, and for health-care providers in Europe. The implementation of this guideline requires multidisciplinary structures of care, and defined processes of diagnosis and treatment.

Limited role for extended maintenance temozolomide for newly diagnosed glioblastoma

OBJECTIVE

To explore an association with survival of modifying the current standard of care for patients with newly diagnosed glioblastoma of surgery followed by radiotherapy plus concurrent and 6 cycles of maintenance temozolomide chemotherapy (TMZ/RT → TMZ) by extending TMZ beyond 6 cycles.

METHODS

The German Glioma Network cohort was screened for patients with newly diagnosed glioblastoma who received TMZ/RT → TMZ and completed ≥6 cycles of maintenance chemotherapy without progression. Associations of clinical patient characteristics, molecular markers, and residual tumor determined by magnetic resonance imaging after 6 cycles of TMZ with progression-free survival (PFS) and overall survival (OS) were analyzed with the log-rank test. Multivariate analyses using the Cox proportional hazards model were performed to assess associations of prolonged TMZ use with outcome.

RESULTS

Sixty-one of 142 identified patients received at least 7 maintenance TMZ cycles (median 11, range 7-20). Patients with extended maintenance TMZ treatment had better PFS (20.5 months, 95% confidence interval [CI] 17.7-23.3, vs 17.2 months, 95% CI 10.2-24.2, p = 0.035) but not OS (32.6 months, 95% CI 28.9-36.4, vs 33.2 months, 95% CI 25.3-41.0, p = 0.126). However, there was no significant association of prolonged TMZ chemotherapy with PFS (hazard ratio [HR] = 0.8, 95% CI 0.4-1.6, p = 0.559) or OS (HR = 1.6, 95% CI 0.8-3.3, p = 0.218) adjusted for age, extent of resection, Karnofsky performance score, presence of residual tumor, O⁶-methylguanine DNA methyltransferase (MGMT) promoter methylation status, or isocitrate dehydrogenase (IDH) mutation status.

CONCLUSION

These data may not support the practice of prolonging maintenance TMZ chemotherapy beyond 6 cycles.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients with newly diagnosed glioblastoma, prolonged TMZ chemotherapy does not significantly increase PFS or OS.

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.

Intracerebroventricular Delivery as a Safe, Long-Term Route of Drug Administration

Intrathecal delivery methods have been used for many decades to treat a broad range of central nervous system disorders. A literature review demonstrated that intracerebroventricular route is an established and well-tolerated method for prolonged central nervous system drug delivery in pediatric and adult populations. Intracerebroventricular devices were present in patients from one to 7156 days. The number of punctures per device ranged from 2 to 280. Noninfectious complication rates per patient (range, 1.0% to 33.0%) were similar to infectious complication rates (0.0% to 27.0%). Clinician experience and training and the use of strict aseptic techniques have been shown to reduce the frequency of complications.

Randomized, Double-Blind, Placebo-Controlled, Multicenter Phase II Study of Onartuzumab Plus Bevacizumab Versus Placebo Plus Bevacizumab in Patients With Recurrent Glioblastoma: Efficacy, Safety, and Hepatocyte Growth Factor and O6-Methylguanine–DNA Methyltransferase Biomarker Analyses

Purpose

Bevacizumab regimens are approved for the treatment of recurrent glioblastoma in many countries. Aberrant mesenchymal-epithelial transition factor (MET) expression has been reported in glioblastoma and may contribute to bevacizumab resistance. The phase II study GO27819 investigated the monovalent MET inhibitor onartuzumab plus bevacizumab (Ona + Bev) versus placebo plus bevacizumab (Pla + Bev) in recurrent glioblastoma.

Methods

At first recurrence after chemoradiation, bevacizumab-naïve patients with glioblastoma were randomly assigned 1:1 to receive Ona (15 mg/kg, once every 3 weeks) + Bev (15 mg/kg, once every 3 weeks) or Pla + Bev until disease progression. The primary end point was progression-free survival by response assessment in neuro-oncology criteria. Secondary end points were overall survival, objective response rate, duration of response, and safety. Exploratory biomarker analyses correlated efficacy with expression levels of MET ligand hepatocyte growth factor, O6-methylguanine–DNA methyltransferase promoter methylation, and glioblastoma subtype.

Results

Among 129 patients enrolled (Ona + Bev, n = 64; Pla + Bev, n = 65), baseline characteristics were balanced. The median progression-free survival was 3.9 months for Ona + Bev versus 2.9 months for Pla + Bev (hazard ratio, 1.06; 95% CI, 0.72 to 1.56; P = .7444). The median overall survival was 8.8 months for Ona + Bev and 12.6 months for Pla + Bev (hazard ratio, 1.45; 95% CI, 0.88 to 2.37; P = .1389). Grade ≥ 3 adverse events were reported in 38.5% of patients who received Ona + Bev and 35.9% of patients who received Pla + Bev. Exploratory biomarker analyses suggested that patients with high expression of hepatocyte growth factor or unmethylated O6-methylguanine–DNA methyltransferase may benefit from Ona + Bev.

Conclusion

There was no evidence of further clinical benefit with the addition of onartuzumab to bevacizumab compared with bevacizumab plus placebo in unselected patients with recurrent glioblastoma in this phase II study; however, further investigation into biomarker subgroups is warranted.

Optical Barcoding for Single-Clone Tracking to Study Tumor Heterogeneity

Intratumoral heterogeneity has been identified as one of the strongest drivers of treatment resistance and tumor recurrence. Therefore, investigating the complex clonal architecture of tumors over time has become a major challenge in cancer research. We developed a new fluorescent "optical barcoding" technique that allows fast tracking, identification, and quantification of live cell clones in vitro and in vivo using flow cytometry (FC). We optically barcoded two cell lines derived from malignant glioma, an exemplary heterogeneous brain tumor. In agreement with mathematical combinatorics, we demonstrate that up to 41 clones can unambiguously be marked using six fluorescent proteins and a maximum of three colors per clone. We show that optical barcoding facilitates sensitive, precise, rapid, and inexpensive analysis of clonal composition kinetics of heterogeneous cell populations by FC. We further assessed the quantitative contribution of multiple clones to glioblastoma growth in vivo and we highlight the potential to recover individual viable cell clones by fluorescence-activated cell sorting. In summary, we demonstrate that optical barcoding is a powerful technique for clonal cell tracking in vitro and in vivo, rendering this approach a potent tool for studying the heterogeneity of complex tissues, in particular, cancer.

EGFR as a Target for Glioblastoma Treatment: An Unfulfilled Promise

The receptor for epidermal growth factor (EGFR) is a prime target for cancer therapy across a broad variety of tumor types. As it is a tyrosine kinase, small molecule tyrosine kinase inhibitors (TKIs) targeting signal transduction, as well as monoclonal antibodies against the EGFR, have been investigated as anti-tumor agents. However, despite the long-known enigmatic EGFR gene amplification and protein overexpression in glioblastoma, the most aggressive intrinsic human brain tumor, the potential of EGFR as a target for this tumor type has been unfulfilled. This review analyses the attempts to use TKIs and monoclonal antibodies against glioblastoma, with special consideration given to immunological approaches, the use of EGFR as a docking molecule for conjugates with toxins, T-cells, oncolytic viruses, exosomes and nanoparticles. Drug delivery issues associated with therapies for intracerebral diseases, with specific emphasis on convection enhanced delivery, are also discussed.

Morphology of Ruptured and Unruptured Intracranial Aneurysms

BACKGROUND

In addition to size and location, the morphology of intracranial aneurysms has been proposed to predict rupture. This study was undertaken to compare morphologic features between ruptured and unruptured aneurysms and identify those associated with greater risk of rupture.

METHODS

Between 2010 and 2014, 301 patients with subarachnoid hemorrhage and 204 with unruptured aneurysms were admitted to our hospital. Two investigators reviewed 3-dimensional angiograms of all aneurysms. Risk factors for rupture were identified. Morphology was classified into single-sac aneurysms with smooth margin, single-sac aneurysms with irregular margin, aneurysms with a daughter sac, and multilobulated aneurysms. The value of morphology in predicting rupture was tested with the use of logistic regression.

RESULTS

A total of 420 aneurysms met the inclusion criteria. Multilobulated aneurysm was the most frequent finding among ruptured aneurysms, followed by single sac with irregular margin, aneurysm with daughter sac, and single sac with smooth margin (44.9%, 25.9%, 18%, and 11.2%, respectively). Among unruptured aneurysms, single sac with smooth margin was the most frequent finding, followed by single sac with irregular margin, multilobulated aneurysm, and aneurysm with daughter sac (38.1%, 29.8%, 20.9%, and 11.2%, respectively). Morphology was an independent predictor of rupture (receiver operating characteristic-area under the curve 0.693, P < 0.001). Risk of rupture increased by factor of 3 (5, 95% confidence interval [CI] 1.6-5.3) from single sac with regular margin to irregular margin, by factor of 5.5 (5, 95% CI 2.8-11.0) to daughter sac, and by factor of 7.3 (5, 95% CI 4.1-13.1) to multilobulated aneurysm.

CONCLUSIONS

Morphology might have an independent predictive value of aneurysm rupture. Risk of rupture might increase according to extent of morphologic change. Prospective studies will be necessary to evaluate the influence of aneurysm morphology on natural history.