Epilepsy in patients with brain tumours: epidemiology, mechanisms, and management

Glioma-Induced Alterations in Neuronal Activity and Neurovascular Coupling during Disease Progression

Diffusely infiltrating gliomas are known to cause alterations in cortical function, vascular disruption, and seizures. These neurological complications present major clinical challenges, yet their underlying mechanisms and causal relationships to disease progression are poorly characterized. Here, we follow glioma progression in awake Thy1-GCaMP6f mice using in vivo wide-field optical mapping to monitor alterations in both neuronal activity and functional hemodynamics. The bilateral synchrony of spontaneous neuronal activity gradually decreases in glioma-infiltrated cortical regions, while neurovascular coupling becomes progressively disrupted compared to uninvolved cortex. Over time, mice develop diverse patterns of high amplitude discharges and eventually generalized seizures that appear to originate at the tumors' infiltrative margins. Interictal and seizure events exhibit positive neurovascular coupling in uninfiltrated cortex; however, glioma-infiltrated regions exhibit disrupted hemodynamic responses driving seizure-evoked hypoxia. These results reveal a landscape of complex physiological interactions occurring during glioma progression and present new opportunities for exploring novel biomarkers and therapeutic targets.

Epileptogenesis and oncogenesis: An antineoplastic role for antiepileptic drugs in brain tumours?

The first description of epileptic seizures due to brain tumours occurred in 19th century. Nevertheless, after over one hundred years, scientific literature is still lacking on how epilepsy and its treatment can affect tumour burden, progression and clinical outcomes. In patients with brain tumours, epilepsy dramatically impacts their quality of life (QoL). Even antiepileptic therapy seems to affect tumor lesion development. Numerous studies suggest that certain actors involved in epileptogenesis (inflammatory changes, glutamate and its ionotropic and metabotropic receptors, GABA-A and its GABA-AR receptor, as well as certain ligand- and voltage-gated ion channel) may also contribute to tumorigenesis. Although some antiepileptic drugs (AEDs) are known operating on such mechanisms underlying epilepsy and tumor development, few preclinical and clinical studies have tried to investigate them as targets of pharmacological tools acting to control both phenomena. The primary aim of this review is to summarize known determinants and pathophysiological mechanisms of seizures, as well as of cell growth and spread, in patients with brain tumors. Therefore, a special focus will be provided on the anticancer effects of commonly prescribed AEDs (including levetiracetam, valproic acid, oxcarbazepine and others), with an overview of both preclinical and clinical data. Potential clinical applications of this finding are discussed.

Prophylactic anticonvulsant therapy in high-grade glioma: A systematic review and meta-analysis of longitudinal studies

INTRODUCTION

It is common practice to prescribe prophylactic antiepileptic drugs (AED) to high-grade glioma (HGG) patients without a history of seizures, yet with limited evidence supporting its use. Ideally, the effectiveness of prophylactic anticonvulsants must outweigh the occurrence of adverse effects and interactions related to AED. The authors conducted a systematic review and metanalysis of longitudinal studies regarding the effectiveness of prophylactic AED in seizure-naïve HGG patients.

MATERIALS AND METHODS

PubMed/MEDLINE, Cochrane Central Register of Controlled trials, Embase and clinicaltrials.gov databases were systematically searched. Of the initial 1773 studies identified, 15 were finally selected for data extraction and analysis. Heterogeneity among studies, pooled hazard ratios, publication bias and sensitivity analyses were performed separately for a 15-study group (HGG patients within larger series of brain tumors) and a 6-study group (exclusively HGG patients).

RESULTS

AED prophylaxis did not significantly reduce the incidence of postoperative seizures compared with controls, both in the 15-study group (Mantel-Haenszel random-effects pooled OR 1.08, 95% CI 0.82-1.43, 2123 patients) and in the 6-study group (pooled OR 1.22, 95% CI 0.77-1.92, 540 patients). However, some issues (paucity of prospective trials, overall moderate-risk of bias, and few studies addressing HGG patients exclusively) preclude firm conclusions against routine prophylactic AED prescription. Reported adverse effects attributable to AED were acceptable in the majority of studies.

CONCLUSIONS

Within the limitations of this review, the results of this metanalysis do not support the routine administration of prophylactic AED to HGG patients without a history of seizures.

Treatment of epilepsy in adults: Expert opinion in South Korea

OBJECTIVE

The aim of this study was to gather the expert opinions of Korean epileptologists regarding the treatment of adult patients with epilepsy.

METHODS

A total of 42 neurologists who specialized in epilepsy were surveyed. They completed an online questionnaire describing multiple patient scenarios. Using these scenarios, they evaluated treatment strategies and gave their preference for specific antiepileptic drugs (AEDs) used to treat genetically mediated generalized epilepsy and focal epilepsy.

RESULTS

Initial AED monotherapy, followed by a second form of alternative monotherapy or an add-on combination therapy, was the preferred treatment strategy. The experts reached consensus for 87.2% of the items. The most commonly selected AEDs for the initial monotherapy for patients with generalized epilepsy were levetiracetam or valproate. For those with focal epilepsy, levetiracetam, oxcarbazepine, or lamotrigine were the most popular selections. Ethosuximide was the treatment of choice only for patients with generalized epilepsy with prominent absence seizures. Levetiracetam was preferred as an add-on therapy for both generalized and focal epilepsy. For special populations of patients, such as elderly adults or those with comorbid diseases, levetiracetam or lamotrigine was selected as the treatment of choice.

CONCLUSION

Most of the survey results were in accordance with the US expert opinion survey published in 2016. This survey can assist clinicians in making clinical decisions when treating individual adult patients with epilepsy.

Predicting the Type of Tumor-Related Epilepsy in Patients With Low-Grade Gliomas: A Radiomics Study

Purpose: The majority of patients with low-grade gliomas (LGGs) experience tumor-related epilepsy during the disease course. Our study aimed to build a radiomic prediction model for LGG-related epilepsy type based on magnetic resonance imaging (MRI) data.

Methods: A total of 205 cases with LGG-related epilepsy were enrolled in the retrospective study and divided into training and validation cohorts (1:1) according to their surgery time. Seven hundred thirty-four radiomic features were extracted from T2-weighted imaging, including six location features. Pearson correlation coefficient, univariate area under curve (AUC) analysis, and least absolute shrinkage and selection operator regression were adopted to select the most relevant features for the epilepsy type to build a radiomic signature. Furthermore, a novel radiomic nomogram was developed for clinical application using the radiomic signature and clinical variables from all patients.

Results: Four MRI-based features were selected from the 734 radiomic features, including one location feature. Good discriminative performances were achieved in both training (AUC = 0.859, 95% CI = 0.787–0.932) and validation cohorts (AUC = 0.839, 95% CI = 0.761–0.917) for the type of epilepsy. The accuracies were 80.4 and 80.6%, respectively. The radiomic nomogram also allowed for a high degree of discrimination. All models presented favorable calibration curves and decision curve analyses.

Conclusion: Our results suggested that the MRI-based radiomic analysis may predict the type of LGG-related epilepsy to enable individualized therapy for patients with LGG-related epilepsy.

An observational case-control study comparing the recovery profile in patients receiving additional dose of anticonvulsant vs. regular dose during supratentorial craniotomy

Background and Aims:

Anticonvulsants are used routinely for seizure prophylaxis in patients with supratentorial tumour who present with/without seizures. Excessive use of prophylactic anticonvulsant may delay the recovery from anaesthesia. We have studied the recovery profiles of patients who received an additional dose of anticonvulsant in comparison with those who received only the regular dose.

Methods:

In this prospective observational study, patients were anaesthetised using standard anaesthesia protocol. An additional dose of anticonvulsant was administered in one group, while the other group received only the regular dose. Time taken for extubation, eye opening, obeying commands and orientation were compared between the two groups. Haemodynamics, depth of anaesthesia, the plasma anticonvulsant levels and the incidence of seizures were compared between the two groups.

Results:

A total of 36 patients were studied, of which 19 received regular dose and 17 received an additional dose. There was no significant difference in recovery time between the two groups. Subgroup analysis was performed for phenytoin and sodium valproate. There was a clinically significant delay in recovery in patients who received an additional phenytoin compared to those who received regular dose (time to obey commands >15 min and orientation time >1hour) but, it was not statistically significant. Administration of an additional dose of valproate did not prolong the recovery time.

Conclusion:

An additional dose of sodium valproate did not cause a delay in recovery both, clinically and statistically. However, the administration of an additional dose of phenytoin caused a clinically significant delay in recovery but was not statistically significant.

The risk of developing seizures before and after surgery for brain metastases

OBJECTIVE

Several risk factors have been shown to be associated with pre- and postoperative seizures in patients undergoing neurosurgical intervention for meningiomas and other primary brain tumors. This study aimed to identify risk factors associated with pre- and postoperative seizures in patients undergoing surgery for brain metastases (BM).

PATIENTS AND METHODS

286 patients who had undergone neurosurgical resection for brain metastases between 2007 and 2015 were included in this single-center retrospective cohort. Seizure incidence and patient characteristics were recorded. Univariate and multivariate logistic regression was performed for both pre- and postoperative seizures.

RESULTS

16.8 % of patients presented with seizures before surgical intervention, and a further 7.7 % of patients developed seizures within 3 months of surgical resection of BM. Patient age, cerebellar location, large tumor size, and headache were negatively correlated with pre-operative seizures, whereas parietal location was positively correlated. Surgery for recurrent tumor was positively correlated with newly developed seizures after surgery.

CONCLUSION

Age, cerebellar location, large tumor size, and headache were negatively correlated with development of seizures while parietal location was found to be a risk factor. Lower age and resection of recurrent tumors was correlated with an increased risk of developing postoperative seizures. There was no correlation between type of primary tumor and development of seizures.

Low-grade developmental and epilepsy associated brain tumors: a critical update 2020

Brain tumors represent the second most frequent etiology in patients with focal seizure onset before 18 years of age and submitted to epilepsy surgery. Hence, this category of brain tumors, herein defined as low-grade, developmental, epilepsy-associated brain tumors (LEAT) is different from those frequently encountered in adults as (A): 77% of LEAT occur in the temporal lobe; (B): the vast majority of LEAT are of low malignancy and classified as WHO I°; (C): LEAT are often composed of mixed glial and neuronal cell components and present with variable growth patterns including small cysts or nodules; (D): LEAT do not share common gene driving mutations, such as IDH1 or 1p/19q co-deletions. Characteristic entities comprise the ganglioglioma (GG), the dysembryoplastic neuroepithelial tumor (DNT), the angiocentric glioma (AG), the isomorphic diffuse glioma (IDG) and the papillary glio-neuronal tumor (PGNT), representing 73.2% of 1680 tumors collected in a large German series of 6747 patients submitted to epilepsy surgery. In the realm of exciting discoveries of genetic drivers of brain tumors new genes have been also reported for LEAT. BRAF V600E mutations were linked to GG with CD34 expression, FGFR1 mutations to DNT, MYB alterations to AG and also IDG and PRKCA fusions to PGNT, suggesting the possibility to also develop a genetically driven tumor classification scheme for LEAT. Rare availability of LEAT in a single center is a challenging obstacle, however, to systematically unravel the neurobiological nature and clinical behavior of LEAT. Other challenges in need of clarification include malignant tumor progression of LEAT entities, seizure relapse in patients following bulk tumor resection and the controversial issue of associated focal cortical dysplasia as additional pathomechanism. In order to advance our understanding and promote reliable diagnostic work-up of LEAT, we recommend, therefore, international collaboration to achieve our goals.

Epilepsy in brain metastasis: an emerging entity

PURPOSE OF REVIEW

The purpose of this review is to highlight advances in the management of seizures in brain metastases from solid tumors.

RECENT FINDINGS

The highest risk for seizures is in patients with melanoma and lung cancer. There is lack of data on the efficacy of antiepileptic drugs (AEDs), but interactions between enzyme-inducing AEDs and anticancer agents must be avoided. Levetiracetam and valproic acid are the most appropriate drugs. Prophylaxis with AEDs for patients with brain metastases without a history of seizures is not recommended. Total resection of a brain metastasis allows complete seizure control. Seizures may represent an adverse effect of stereotactic radiosurgery or of high-dose chemotherapy. New preclinical and clinical studies should define the risk of brain metastasis in light of the new treatment options in the different tumor types. New clinical trials should be designed in patients with brain metastases in terms of treatment or prophylaxis of seizures.

Effect of radiotherapy on freedom from seizures in dogs with brain tumors

Background

Seizures are a common presenting sign in dogs with brain tumors.

Hypothesis/Objectives

To investigate the effect of radiotherapy on freedom from brain tumor‐associated seizures and survival time in dogs.

Animals

Thirty‐two client‐owned dogs with brain tumor‐associated seizures; 18 received medical treatment and radiotherapy, 14 received medical treatment alone.

Methods

Multicenter retrospective study. Baseline characteristics (seizure semiology, magnetic resonance imaging [MRI] characteristics, and treatment) and duration of seizure freedom were recorded for the 2 treatment groups. Duration of seizure freedom between groups was compared (log‐rank test) using Cox's proportional hazard analysis, with baseline characteristics entered as covariates.

Results

The duration of seizure freedom and survival time were significantly longer in the radiotherapy group (P < .001), with a mean of 24 months (95% confidence interval [CI], 14.3‐33.8) versus 1.7 months in the control group (95% CI, 0.5‐2.9) and a mean of 34.6 months (95% CI: 25.2‐44.1) versus 6.2 months in the control group (95% CI, 2.6‐9.7) respectively. Baseline characteristics were not associated with duration of seizure freedom after the start of treatment. In the radiotherapy group, 5 dogs were euthanized during the study period because of causes other than seizures. In the control group, recurrence of seizures was observed before death in all dogs.

Conclusions and Clinical Importance

A longer period of seizure freedom and longer survival time was observed in dogs with brain tumors after radiotherapy compared to medical treatment only. The pathophysiological mechanisms of epileptogenesis and the effect of radiation therapy on seizure control are unclear to date. Further prospective studies are needed.

PIK3CA variants selectively initiate brain hyperactivity during gliomagenesis

Glioblastoma is a universally lethal form of brain cancer that exhibits an array of pathophysiological phenotypes, many of which are mediated by interactions with the neuronal microenvironment1,2. Recent studies have shown that increases in neuronal activity have an important role in the proliferation and progression of glioblastoma3,4. Whether there is reciprocal crosstalk between glioblastoma and neurons remains poorly defined, as the mechanisms that underlie how these tumours remodel the neuronal milieu towards increased activity are unknown. Here, using a native mouse model of glioblastoma, we develop a high-throughput in vivo screening platform and discover several driver variants of PIK3CA. We show that tumours driven by these variants have divergent molecular properties that manifest in selective initiation of brain hyperexcitability and remodelling of the synaptic constituency. Furthermore, secreted members of the glypican (GPC) family are selectively expressed in these tumours, and GPC3 drives gliomagenesis and hyperexcitability. Together, our studies illustrate the importance of functionally interrogating diverse tumour phenotypes driven by individual, yet related, variants and reveal how glioblastoma alters the neuronal microenvironment.

Perioperative fatigue in patients with diffuse glioma

Purpose

Few studies have assessed fatigue in relation to glioma surgery. The purpose of this study was to explore the prevalence of pre- and postoperative high fatigue, perioperative changes, and factors associated with pre- and postoperative high fatigue in patients undergoing primary surgery for diffuse glioma.

Methods

A total of 112 adult patients were prospectively included. Patient-reported fatigue was assessed before and one month after surgery using the cancer-specific European Organization for Research and Treatment of Cancer questionnaire fatigue subscale. The scores were dichotomized as high fatigue (≥ 39) or low fatigue (< 39). A change in score of ≥ 10 was considered as a clinically significant change. Factors associated with pre- and postoperative high fatigue were explored in multivariable regression analyses.

Results

High fatigue was reported by 45% of the patients preoperatively and by 42% of the patients postoperatively. Female gender and low Karnofsky Performance Status (KPS) were associated with preoperative high fatigue, while postoperative complications, low KPS and low-grade histopathology were associated with postoperative high fatigue. In total 35/92 (38%) patients reported a clinically significant improvement of fatigue scores after surgery, 36/92 (39%) patients reported a clinically significant worsening of fatigue scores after surgery, and 21/92 (23%) patients reported no clinically significant change in fatigue scores after surgery. Patients with low-grade gliomas more often reported low fatigue before surgery and high fatigue after surgery, while patients with high-grade gliomas more often reported high fatigue before surgery and low fatigue after surgery.

Conclusions

Our findings indicate that fatigue is a common symptom in patients with diffuse glioma, both pre- and postoperatively. Perioperative changes were frequently seen. This is important knowledge when informing patients before and after surgery.

Electronic supplementary material

The online version of this article (10.1007/s11060-020-03403-0) contains supplementary material, which is available to authorized users.

Seizures in patients with cancer

Seizures are common in patients with cancer and either result from brain lesions, paraneoplastic syndromes, and complications of cancer treatment or are provoked by systemic illness (metabolic derangements, infections). Evaluation should include a tailored history, neurologic examination, laboratory studies, neuroimaging, and electroencephalogram. In unprovoked seizures, antiepileptic drug (AED) treatment is required, and a nonenzyme-inducing AED is preferred. Treatment of the underlying cancer with surgery, chemotherapy, and radiation therapy also can help reduce seizures. Benzodiazepines are useful in the treatment of both provoked seizures and breakthrough epileptic seizures and as first-line treatment for status epilepticus. Counseling for safety is an important component in the care of a patient with cancer who has seizures. Good seizure management can be challenging but significantly improves the quality of life during all phases of care, including end-of-life care.

Multimodal Assessment Shows a Mostly Preserved Cognitive Status in Incidentally Discovered Low Grade Gliomas: A Single Institution Study

Incidentally discovered low-grade gliomas (iLGGs) are poorly reported in the literature. Still less is known about iLGG patients’ neuropsychological profile: It is unclear whether iLGG patients are cognitively proficient, thus further confirming the concept of asymptomatic. From our monoinstitutional cohort of 332 patients operated for LGG from 2000 to 2017 we selected those who underwent a neuropsychological testing (n = 217, from 2008 to 2017), and identified 24 young (mean age 38.5 ± 1.06) patients with iLGGs (16 of 24, left hemisphere iLGGs, 8 of 24 right hemisphere iLGGs). The maximum lesions overlap occurred in the left inferior frontal gyrus and in the right anterior cingulate/superior medial frontal gyrus. Patients were cognitively preserved except mild to borderline difficulties in a few of them. The analysis of the equivalent scores (a score laying below or equal to the external nonparametric tolerance limit of adjusted scores corresponding to 0, 1, 2 and 3 are intermediate) highlighted the presence of additional borderline performances. Molecular class correlated with a normal function at visual–spatial intelligence (p = 0.05) and at spatial short-term memory (p = 0.029). Results indicate that at this time of tumor growth, patients’ cognitive abilities are still functional, but are slowly approaching the borderline level.

Benign and malignant tumors of the central nervous system and pregnancy

Tumors of the central nervous system (CNS) are rare entities, typically affecting the very young or the very old, but span a spectrum of disease that may present in any age group. Women of reproductive age are more likely to be affected by benign tumors, including pituitary adenomas and meningiomas, and aggressive intracranial malignancies, such as brain metastases and glioblastoma, rarely present in pregnancy. Definitive management of CNS tumors may involve multimodal therapy, including surgery, radiation, and chemotherapy, and each of these treatments carries risk to the mother and developing fetus. CNS tumors often present with challenging and morbid symptoms such as headache and seizure, which need to be managed throughout a pregnancy. Decisions about timing treatment during pregnancy or delaying until after delivery, continuing or electively terminating a pregnancy, and future family planning and fertility are complex and require a multidisciplinary care team to evaluate the implications to both mother and baby. There are no guidelines or consensus recommendations regarding brain tumor management in pregnancy, and thus, individual treatment decisions are made by the care team based on experiential evidence, extrapolation of guidelines for nonpregnant patients, and patient values and preferences.

Seizures in meningioma

More than one-third of patients with meningiomas will experience seizures at some point in their disease. Despite this, meningioma-associated epilepsy remains significantly understudied, as most investigations focus on tumor progression, extent of resection, and survival. Due to the impact of epilepsy on the patient's quality of life, identifying predictors of preoperative seizures and postoperative seizure freedom is critical. In this chapter, we review previously reported rates and predictors of seizures in meningioma and discuss surgical and medical treatment options. Preoperative epilepsy occurs in approximately 30% of meningioma patients with peritumoral edema on neuroimaging being one of the most significant predictor of seizures. Other associated factors include age <18, male gender, the absence of headache, and non-skull base tumor location. Following tumor resection, approximately 70% of individuals with preoperative epilepsy achieve seizure freedom. Variables associated with persistent seizures include a history of preoperative epilepsy, peritumoral edema, skull base tumor location, tumor progression, and epileptiform discharges on postoperative electroencephalogram. In addition, after surgery, approximately 10% of meningioma patients without preoperative epilepsy experience new seizures. Variables associated with new postoperative seizures include tumor progression, prior radiation exposure, and gross total tumor resection. Both pre- and postoperative meningioma-related seizures are often responsive to antiepileptic drugs (AEDs), although AED prophylaxis in the absence of seizures is not recommended. AED selection is based on current guidelines for treating focal seizures with additional considerations including efficacy in tumor-related epilepsy, toxicities, and potential drug-drug interactions. Continued investigation into medical and surgical strategies for preventing and alleviating epilepsy in meningioma is warranted.

Patterns of seizure prophylaxis after oncologic neurosurgery

BACKGROUND

Evidence supporting routine postoperative antiepileptic drug (AED) prophylaxis following oncologic neurosurgery is limited, and actual practice patterns are largely unknown beyond survey data.

OBJECTIVE

To describe patterns and predictors of postoperative AED prophylaxis following intracranial tumor surgery.

METHODS

The MarketScan Database was used to analyze pharmacy claims data and clinical characteristics in a national sample over a 5-year period.

RESULTS

Among 5895 patients in the cohort, levetiracetam was the most widely used AED for prophylaxis (78.5%) followed by phenytoin (20.5%). Prophylaxis was common but highly variable for patients who underwent open resection of supratentorial intraparenchymal tumors (62.5%, reference) or meningiomas (61.9%). In multivariate analysis, biopsies were less likely to receive prophylaxis (44.8%, OR 0.47, 95% CI 0.33-0.67), and there was near consensus against prophylaxis for infratentorial (9.7%, OR 0.07, CI 0.05-0.09) and transsphenoidal procedures (0.4%, OR 0.003, CI 0.001-0.010). Primary malignancies (52.1%, reference) and secondary metastases (42.2%) were more likely to receive prophylaxis than benign tumors (23.0%, OR 0.63, CI 0.48-0.83), as were patients discharged with home services and patients in the Northeast. There was a large spike in duration of AED use at approximately 30 days.

CONCLUSIONS

Use of seizure prophylaxis following intracranial biopsies and supratentorial resections is highly variable, consistent with a lack of guidelines or consensus. Current practice patterns do not support a clear standard of care and may be driven in part by geographic variation, availability of post-discharge services, and electronic prescribing defaults rather than evidence. Given uncertainty regarding effectiveness, indications, and appropriate duration of AED prophylaxis, well-powered trials are needed.

Surgical treatment of drug-resistant epilepsy caused by gliomas in eloquent areas: experience report

INTRODUCTION

Drug-resistant epilepsy associated with central nervous system tumors is generally caused by low grade gliomas. This group of tumors is usually found in brain eloquent areas, such as the insular lobe, rolandic cortex and supplementary motor area and, historically, possess a greater risk of postoperative deficits.

OBJECTIVE

The aim of this investigation was to present our surgical experience on patients with drug-resistant epilepsy caused by gliomas in eloquent areas. We retrospectively investigated variables that impact seizure control, such as tumor location, extent of resection, invasion into the lenticulostriate arteries in the patient, especially those with insular gliomas.

METHODS

Out of 67 patients with eloquent area brain tumors operated on in our service between 2007 and 2016, 14 patients had symptoms of drug-resistant epilepsy. Volumetric analysis, extent of resection (EOR), type of approach and mapping, among other factors were correlated with the 12-month postoperative seizure outcome.

RESULTS

Univariate analysis showed that the factors showing statistical relevance with seizure control were preoperative volume (p = 0.005), EOR (p = 0.028) and postoperative volume (p = 0.030).

CONCLUSION

There was a statistically significant association between the EOR and the Engel score for epilepsy control: an EOR < 70 was associated with Engel II, III, IV and an EOR > 90 was associated with Engel I. Eloquent area gliomas can safely be resected when surgeons use not only microsurgical anatomy concepts but also brain mapping.

Tumor-associated status epilepticus in patients with glioma: Clinical characteristics and outcomes

Between 3 and 12% of all adult status epilepticus (SE) are caused by a brain tumor. Gliomas, and in particular, high-grade gliomas (HGGs), are at high risk of SE development. In this study, we aimed to describe the clinical characteristic and outcomes of tumor-associated SE (TASE) in a population of adult patients with glioma prospectively collected between 2013 and 2019. In the aforementioned period, we observed 26 TASE (median age: 68 years). Overall, 22 patients (85%) presented a HGG (one anaplastic astrocytoma and 21 a glioblastoma) while 4 had a LGG (two diffuse astrocytoma and two ganglioglioma). All the lesions were supratentorial, and the temporal lobe was the most frequently involved (20 patients). Fourteen patients (54%) had the SE episode as the first manifestation of the tumor; in the remaining 12 (all patients with a HGG), the development of SE heralded tumor progression or reappearance. When TASE outcomes were compared with the ones observed in the general population of SE (SEGP), the response to treatment was not different between the two populations (refractory SE (RSE)/super-refractory SE (SRSE) 12% versus 13%, p = 0.75). In the short-term, group with TASE had a significantly lower global disability (modified Rankin scale (mRS) < 3 at discharge: 60% versus 32%, p < 0.001; at 30 days follow-up: 62% versus 30%, p < 0.001) and mortality (30 days mortality: 4% versus 27%, p = 0.008). Six months and 1 year mortality did not show any difference between the two groups (6 months: 46% and 45%, respectively, p = 0.9; 1 year: 68% and 52%, respectively, p = 0.22). The appearance of TASE often heralds tumor grow and progression. Even in this context, it appears to be as treatment-responsive as SEGP and the short-term disability and mortality related to SE episode are lower than those observed in the SEGP. Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures.

Perampanel attenuates epileptiform phenotype in C6 glioma

Epileptic seizures are frequent in patients with glioma, and anticonvulsive treatment is often indicated. Glioma cells release glutamate via the X_c- antiporter system, which appears to be a major pathomechanism of glioma-associated seizures and excitotoxicity. In addition, the proliferation and survival of the tumor cells are promoted. Therefore, anticonvulsants that attenuate glutamate-mediated receptor activation could be especially effective. In this study, we investigated the effects of AMPA receptor antagonist perampanel in rat C6 glioma model. In first pilot experiments, perampanel reduced glucose uptake but had no impact of extracellular glutamate level in vitro. To analyze the effects of perampanel in vivo, we injected C6 cells orthotopically into the neocortex of Wistar rats in order to establish a model of glioma-associated epilepsy. Spontaneous recurrent discharges in brain slices were abolished upon perfusion with the AMPA receptor blocker perampanel, supporting the major role of glutamatergic excitation. With respect to the tumor progression, no effect of perampanel on survival of the animals or on glioma size was determined. Our data demonstrate that perampanel inhibit epileptiform discharges in organotypic brain slices of glioma, but failed to attenuate tumor growth or promote animal survival.

Ex vivo multi-electrode analysis reveals spatiotemporal dynamics of ictal behavior at the infiltrated margin of glioma

The purpose of this study is to develop a platform in which the cellular and molecular underpinnings of chronic focal neocortical lesional epilepsy can be explored and use it to characterize seizure-like events (SLEs) in an ex vivo model of infiltrating high-grade glioma. Microelectrode arrays were used to study electrophysiologic changes in ex vivo acute brain slices from a PTEN/p53 deleted, PDGF-B driven mouse model of high-grade glioma. Electrode locations were co-registered to the underlying histology to ascertain the influence of the varying histologic landscape on the observed electrophysiologic changes. Peritumoral, infiltrated, and tumor sites were sampled in tumor-bearing slices. Following the addition of zero Mg²⁺ solution, all three histologic regions in tumor-bearing slices showed significantly greater increases in firing rates when compared to the control sites. Tumor-bearing slices demonstrated increased proclivity for SLEs, with 40 events in tumor-bearing slices and 5 events in control slices (p-value = .0105). Observed SLEs were characterized by either low voltage fast (LVF) onset patterns or short bursts of repetitive widespread, high amplitude low frequency discharges. Seizure foci comprised areas from all three histologic regions. The onset electrode was found to be at the infiltrated margin in 50% of cases and in the peritumoral region in 36.9% of cases. These findings reveal a landscape of histopathologic and electrophysiologic alterations associated with ictogenesis and spread of tumor-associated seizures.

Seizures in cancer patients: a vast spectrum of etiologies

Aim: This study aims to recognize the distribution of different seizures etiologies in cancer patients, the most common primary tumors responsible for brain metastases, the most epileptogenic primary tumors and the therapeutic modalities. Methods: A retrospective study was conducted at Hotel-Dieu de France Hospital targeting patients admitted to hematology–oncology department between 2005 and 2016 who presented a seizure. Results: Of the 153 included patients, mean age was 57 years (standard deviation = 16 years) and a male predominance (66%). The majority of seizures were due to a primary tumor (49%) or brain metastases (32%). Other reversible (metabolic and drug) or nonreversible causes (carcinomatous meningitis, radiation and cardiovascular complications) formed the remaining causes. Regarding antiepileptic treatments, sodium valproate was mostly used, followed by levetiracetam and phenytoin. Conclusion: Numerous reversible causes are involved in the onset of epileptic seizures, including metabolic disorders, antibiotics and chemotherapies.

The fence post depth electrode technique to control both brain tumors and epileptic seizures in patients with brain tumor-related epilepsy

Background:

To control brain tumor-related epilepsy (BTRE), both epileptological and neuro-oncological approaches are required. We hypothesized that using depth electrodes (DEs) as fence post catheters, we could detect the area of epileptic seizure onset and achieve both brain tumor removal and epileptic seizure control.

Methods:

Between August 2009 and April 2018, we performed brain tumor removal for 27 patients with BTRE. Patients who underwent lesionectomy without DEs were classified into Group 1 (13 patients) and patients who underwent the fence post DE technique were classified into Group 2 (14 patients).

Results:

The patients were 15 women and 12 men (mean age, 28.1 years; median age 21 years; range, 5–68 years). The brain tumor was resected to a greater extent in Group 2 than Group 1 (P < 0.001). Shallower contacts showed more epileptogenicity than deeper contacts (P < 0.001). Group 2 showed better epilepsy surgical outcomes than Group 1 (P = 0.041).

Conclusion:

Using DEs as fence post catheters, we detected the area of epileptic seizure onset and controlled epileptic seizures. Simultaneously, we removed the brain tumor to a greater extent with fence post DEs than without.

Incidence, risk factors and outcomes of seizures occurring after craniotomy for primary brain tumor resection

Objective:

To determine the incidence, risk factors and outcomes of early post-craniotomy seizures.

Method:

This was a retrospective cohort study of all patients who underwent craniotomy for primary brain tumor resection (2002-2011) and admitted postoperatively to the intensive care unit. The patients were divided into 2 groups depending on the occurrence of seizures within 7 days.

Results:

One-hundred-ninety-three patients were studied: 35.8% had preoperative seizure history and 16.6% were on prophylactic antiepileptic drugs (AEDs). Twenty-seven (14%) patients had post-craniotomy seizures. The tumors were mostly meningiomas (63% for the post-craniotomy seizures group versus 58.1% for the other group; p=0.63) and supratentorial (92.6% for the post-craniotomy seizures versus 78.4% for the other group, p=0.09) with tumor diameter=3.7±1.5 versus 4.2±1.6 cm, (p=0.07). One (3.1%) of the 32 patients on prophylactic AEDs had post-craniotomy seizures compared with 12% of the 92 patients not receiving AEDs preoperatively (p=0.18). On multivariate analysis, predictors of post-craniotomy seizures were preoperative seizures (odds ratio, 2.62; 95% confidence interval, 1.12-6.15) and smaller tumor size <4 cm (odds ratio, 2.50; 95% confidence interval, 1.02-6.25). Post-craniotomy seizures were not associated with increased morbidity or mortality.

Conclusion:

Early seizures were common after craniotomy for primary brain tumor resection, but were not associated with worse outcomes. Preoperative seizures and smaller tumor size were independent risk factors.

Clinical practice guidelines for the diagnosis and treatment of adult diffuse glioma-related epilepsy

BACKGROUND

Glioma-related epilepsy (GRE) is defined as symptomatic epileptic seizures secondary to gliomas, it brings both heavy financial and psychosocial burdens to patients with diffuse glioma and significantly decreases their quality of life. To date, there have been no clinical guidelines that provide recommendations for the optimal diagnostic and therapeutic procedures for GRE patients.

METHODS

In March 2017, the Joint Task Force for GRE of China Association Against Epilepsy and Society for Neuro-Oncology of China launched the guideline committee for the diagnosis and treatment of GRE. The guideline committee conducted a comprehensive review of relevant domestic and international literatures that were evaluated and graded based on the Oxford Centre for Evidence-Based Medicine Levels of Evidence, and then held three consensus meetings to discuss relevant recommendations. The recommendations were eventually given according to those relevant literatures, together with the experiences in the diagnosis and treatment of over 3000 GRE cases from 24 tertiary level hospitals that specialize in clinical research of epilepsy, glioma, and GRE in China.

RESULTS

The manuscript presented the current standard recommendations for the diagnostic and therapeutic procedures of GRE.

CONCLUSIONS

The current work will provide a framework and assurance for the diagnosis and treatment strategy of GRE to reduce complications and costs caused by unnecessary treatment. Additionally, it can serve as a reference for all professionals involved in the management of patients with GRE.

An overview of anti-epileptic therapy management of patients with malignant tumors of the brain undergoing radiation therapy

As our surgical, radiation, chemotherapeutic and supportive therapies for brain malignancies improve, and overall survival is prolonged, appropriate symptom management in this patient population becomes increasingly important. This review summarizes the published literature and current practice patterns regarding prophylactic and perioperative anti-epileptic drug use. As a wide range of anti-epileptic drugs is now available to providers, evidence guiding appropriate anticonvulsant choice is reviewed. A particular focus of this article is radiation therapy for brain malignancies. Toxicities and seizure risk associated with cranial irradiation will be discussed. Epilepsy management in patients undergoing radiation for gliomas, glioblastoma multiforme, and brain metastases will be addressed. An emerging but inconsistent body of evidence, reviewed here, indicates that anti-epileptic medications may increase radiosensitivity, and therefore improve clinical outcomes, specifically in glioblastoma multiforme patients.

Potential influence of IDH1 mutation and MGMT gene promoter methylation on glioma-related preoperative seizures and postoperative seizure control

PURPOSE

To examine the occurrence of glioma-related preoperative seizures (GPS) and post-operative seizure control (PSC) with respect to patients characteristics including five commonly tested tumor molecular markers (TMMs).

METHODS

A single-center retrospective cohort study of patients with glioma evaluated at the Mayo Clinic, Florida between 2016 and 2018.

RESULTS

68 adult patients (mean age = 51-years, 45-males) were included. 46 patients had GPS. 57 patients underwent intra-operative electrocorticography during awake craniotomy-assisted glioma resection. All patients underwent glioma resection (53, gross-total resection) with histologies of pilocytic astrocytoma (n = 2), diffuse astrocytoma (n = 4), oligodendroglioma (n = 14), anaplastic astrocytoma (n = 16), anaplastic oligodendroglioma (n = 1), and glioblastoma (n = 31). 31 (67%) patients had PSC (median follow-up = 14.5 months; IQR = 7-16.5 months). IDH1 mutation (IDH1^mut) was present in 32, ARTX retention in 53, MGMT gene promotor methylation in 15, 1p/19q co-deletion in 15, and over-expression of p53 in 19 patients. Patients with IDH1^mut were more likely to have GPS (p = 0.037) and PSC (p = 0.035) compared to patients with IDH1 wild-type. Patients with MGMT gene promoter methylation were also likely to have PSC (p = 0.032). GPS or PSC did not differ by age, sex, extent of surgery, glioma grade, location, and histopathological subtype, p53 expression, ARTX retention, or 1p/19q co-deletion status.

CONCLUSIONS

GPS and PSC may be associated with IDH1 mutation and MGMT gene promoter methylation status but not other glioma characteristics including tumor grade, location, or histopathology. Prospective studies with larger sample size are needed to clarify the exact mechanisms of GPS and PSC by the various TMMs to identify new treatment targets.

Risk factors and control of seizures in 778 Chinese patients undergoing initial resection of supratentorial meningiomas

This retrospective study explored the risk factors for the occurrence of seizures in the pre- and postoperative period in patients undergoing supratentorial meningiomas surgery to investigate those who are likely to benefit from prophylactic antiepileptic drugs (AEDs). We reviewed the medical records of 778 supratentorial meningiomas patients who were operated at our institution between 2011 and 2012. A total of 100 (12.9%) patients experienced preoperative seizures; 41 patients (5.3%) experienced postoperative in-hospital seizures, and 91 (13.5%, n = 673) patients experienced postoperative seizures after discharge. Multivariate analysis revealed that motor cortex involvement (odds ratio [OR] 3.243, P < 0.001) and peritumoral edema ≥ 1 cm (OR 3.936, P < 0.001) were significant risk factors of preoperative seizures. Whereas presenting with headache (OR 0.259, P < 0.001) and age ≥ 55 years at surgery (OR 0.514, P = 0.009) showed decreased incidence of preoperative seizures. The involvement of motor cortex (OR 3.290, P = 0.003), postoperative Karnofsky Performance Scale (KPS) ≤ 70 (OR 5.389, P < 0.001), preoperative seizure (OR 4.003, P < 0.001), and occurrence of any medical/surgical complication (OR 3.925, P = 0.001) were significant risk factors for postoperative in-hospital seizures. Postoperative seizures after discharge were associated with tumor maximal diameter ≥ 3.5 cm (OR 1.903, P = 0.022), preoperative seizures (OR 4.350, P < 0.001), postoperative in-hospital seizures (OR 6.385, P < 0.001), and tumor recurrence/progression (OR 7.642, P < 0.001). The probability of seizure freedom in the 5-year follow-up was roughly 59% among patients with preoperative seizures, and 87% among patients without preoperative seizures. Cox regression analysis showed that tumor recurrence/progression (relative risk 2.987, 95% CI 1.517, 5.879, P = 0.002) was the only predictor of postoperative seizures in patients without a history of preoperative epilepsy. The use of postoperative prophylactic antiepileptic drug (AED) did not reduce the incidence of seizures in our analysis. Understanding the risk factors for seizures might help clinicians to predict their occurrence and develop effective anti-epileptic treatment strategies. Further prospective randomized controlled trials are needed to determine the risk factors for seizures and the efficacy of AED prophylaxis.

The Analysis of Risk Factors and Survival Outcome for Chinese Patients with Epilepsy with High-Grade Glioma

OBJECTIVE

To evaluate the risk factors of tumor-related epilepsy (TRE) and the relationship between TRE and functional/survival outcomes in patients with high-grade glioma (HGG).

METHODS

The clinical data of 587 patients with HGG were retrospectively analyzed. A χ² test and logistic multiple-regression analysis were used to analyze factors associated with TRE. Logistic and Cox regression were used to analyze factors that may influence functional and survival outcomes.

RESULTS

Glioma location in temporal (odds ratio [OR], 0.439; P = 0.04) and parietal lobes (OR, 0.092; P = 0.02) were independent protective factors of preoperative epilepsy, compared with gliomas of frontal lobe. Preoperative epilepsy (OR, 9.290; P < 0.001) and dominant hemispheric location (OR, 2.616; P = 0.04) were independent risk factors of postoperative epilepsy. On univariate analysis, patients with preoperative epilepsy had longer progression-free survival (PFS) (P = 0.001) and overall survival (OS) (P < 0.001). Multivariate analysis further confirmed that preoperative epilepsy was an independent protective factor of OS (hazard ratio, 0.587; P = 0.008).

CONCLUSIONS

In patients with HGG, preoperative epilepsy is significantly associated with tumor involvement of the frontal lobe, whereas postoperative epilepsy is associated with preoperative epilepsy and dominant hemispheric location. Also, patients with HGG with preoperative epilepsy have better PFS and OS.

AMPA receptor antagonist perampanel affects glioblastoma cell growth and glutamate release in vitro

Epileptic seizures are frequent in patients with glioblastoma, and anticonvulsive treatment is often necessary. While clinical guidelines recommend all approved anticonvulsants, so far it is still unclear which of the available drugs is the best therapeutic option for treating glioma-associated seizures, also in view of possible anti-tumorigenic effects. In our study, we employed four patient-derived low-passage cell lines of glioblastoma and three cell lines of brain metastases, and challenged these cultures with four anticonvulsants with different mechanisms of action: levetiracetam, valproic acid, carbamazepine and perampanel. Cell proliferation was determined by bromodeoxyuridine incorporation. To further analyze the effects of perampanel, apoptosis induction was measured by caspase 3/7 activation. Glutamate release was quantified and glucose uptake was determined using 18F-fluorodeoxyglucose. Real-time polymerase chain reaction was employed to assess the expression of genes associated with glutamate release and uptake in brain tumor cells. Of the four anticonvulsants, only perampanel showed systematic inhibitory effects on cell proliferation, whereas all other anticonvulsants failed to inhibit glioma and metastasis cell growth in vitro. Metastasis cells were much more resistant to perampanel than glioblastoma cell lines. Glucose uptake was attenuated in all glioblastoma cells after perampanel exposure, whereas cell death via apoptosis was not induced. Extracellular glutamate levels were found to be significantly higher in glioblastoma cell lines as compared to metastasis cell lines, but could be reduced by perampanel exposure. Incubation with perampanel up-regulated glutamine synthetase expression in glioblastoma cells, whereas treatment with valproic acid and levetiracetam downregulated excitatory amino acid transporter-2 expression. Overall, our data suggest that perampanel acts as an anticonvulsive drug and additionally mediated anti-tumorigenic effects.

Anatomical features of primary brain tumors affect seizure risk and semiology

Objective

An epileptic seizure is the most common clinical manifestation of a primary brain tumor. Due to modern neuroimaging, detailed anatomical information on a brain tumor is available early in the diagnostic process and therefore carries considerable potential in clinical decision making. The goal of this study was to gain a better understanding of the relevance of anatomical tumor characteristics on seizure prevalence and semiology.

Methods

We reviewed prospectively collected clinical and imaging data of all patients operated on a supratentorial intraparenchymal primary brain tumor at our department between January 2009 and December 2016. The effect of tumor histology, anatomical location and white matter infiltration on seizure prevalence and semiology were assessed using uni- and multivariate analyses.

Results

Of 678 included patients, 311 (45.9%) presented with epileptic seizures. Tumor location within the central lobe was associated with higher seizure prevalence (OR 4.67, 95% CI: 1.90–13.3, p = .002), especially within the precentral gyrus or paracentral lobule (100%). Bilateral extension, location within subcortical structures and invasion of deeper white matter sectors were associated with a lower risk (OR 0.45, 95% CI: 0.25–0.78; OR 0.10, 95% CI: 0.04–0.21 and OR 0.39, 95% CI: 0.14–0.96, respectively). Multivariate analysis revealed the impact of a location within the central lobe on seizure risk to be highly significant and more relevant than histopathology (OR: 4.79, 95% CI: 1.82–14.52, p = .003). Seizures due to tumors within the central lobe differed from those of other locations by lower risk of secondary generalization (p < .001).

Conclusions

Topographical lobar and gyral location, as well as extent of white matter infiltration impact seizure risk and semiology. This finding may have a high therapeutic potential, for example regarding the use of prophylactic antiepileptic therapy.

•

Brain tumor location affects seizure prevalence and semiology.

•

Central lobe location is the strongest independent pro-epileptogenic factor.

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The precentral gyrus and paracentral lobule are most epileptogenic.

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Central lobe tumors rarely cause bilateral tonic-clonic seizures.

•

Tumor location and white matter infiltration may guide antiepileptic therapy.

Epilepsy Associates with Decreased HIF-1α/STAT5b Signaling in Glioblastoma

Epilepsy at presentation is an independent favorable prognostic factor in glioblastoma (GBM). In this study, we analyze the oncologic signaling pathways that associate with epilepsy in human GBMs, and that can underlie this prognostic effect. Following ethical approval and patient consent, fresh frozen GBM tissue was obtained from 76 patient surgeries. Hospital records were screened for the presence of seizures at presentation of the disease. mRNA and miRNA expression-based and gene set enrichment analyses were performed on these tissues, to uncover candidate oncologic pathways that associate with epilepsy. We performed qPCR experiments and immunohistochemistry on tissue microarrays containing 286 GBMs to further explore the association of these candidate pathways and of markers of mesenchymal transformation (NF-κB, CEBP-β, STAT3, STAT5b, VEGFA, SRF) with epilepsy. Gene sets involved in hypoxia/HIF-1α, STAT5, CEBP-β and epithelial-mesenchymal transformation signaling were significantly downregulated in epileptogenic GBMs. On confirmatory protein expression analyses, epileptogenic tumors were characterized by a significant downregulation of phospho-STAT5b, a target of HIF-1α. Epilepsy status did not associate with molecular subclassification or miRNA expression patterns of the tumors. Epileptogenic GBMs correlate with decreased hypoxia/ HIF-1α/STAT5b signaling compared to glioblastomas that do not present with epilepsy.

Antiepileptic and psychiatric medication in a nationwide cohort of patients with glioma WHO grade II-IV

INTRODUCTION

Glioma is the most common intracranial primary brain tumor. Patients with glioma often suffer from epilepsy, anxiety and depression. Aims of this study were to identify risk factors for drug-treated anxiety and depression, and to determine the use of psychiatric medication in a national glioma cohort.

METHODS

Data from the Cancer Registry of Norway on all persons diagnosed with glioma WHO grade II-IV 2004-2010 were linked with data from the Norwegian Prescription Database. Cox regression analysis was used to assess risk factors for drug-treated anxiety and depression. Standardized incidence ratios were calculated for psychiatric medication dispensed to glioma patients and compared to the general population.

RESULTS

The glioma cohort consisted of 1056 males and 772 females. Of the 1828 patients, 565 had glioma grade II-III, and 1263 had grade IV. The patients with glioma grade II-III who were treated with levetiracetam had an increased risk for drug-treated anxiety compared to patients without levetiracetam; hazard ratio 2.8 (95% confidence interval 1.7-4.9). Female gender increased the risk for drug-treated anxiety compared to males in patients with glioma grade IV; hazard ratio 1.5 (95% confidence interval 1.2-2.0). Antidepressants were less frequently dispensed to patients with glioma grade II-III and epilepsy than to the general population.

CONCLUSIONS

Patients with glioma grade II-III on levetiracetam had an increased risk for drug-treated anxiety. The subgroup of patients with glioma grade II-III and epilepsy received less antidepressants than the general population.

Primary idiopathic CNS non-amyloidogenic light chain deposition disease complicated by treatment-resistant focal seizure disorder

Light chain deposition disease (LCDD) is a systemic disorder characterised by the pathologic deposition of immunoglobulin light chains, which is histologically distinguished from amyloidosis by failure to stain with Congo red. Central nervous system (CNS)-restricted LCDD is among the rarest manifestations. We describe a unique case complicated by focal onset epilepsy with impaired awareness for which control with anticonvulsant therapy proved difficult.

[Treatment of epilepsy in children with brain tumors]

AIM

Symptomatic focal epilepsy is frequently caused by supratentorial brain tumors that may be surgically removed. The authors studied outcomes of surgical treatment depending on the use of electrocorticography c (ECoG).

MATERIAL AND METHODS

Seventy-five children, aged 5-7 years, with supratentorial brain tumors were examined. Symptomatic epilepsy was found in 52 (69.3%) patients. Dysembryoplastic neuroepithelial tumors (DNET) and fibrillary astrocytomas were the most epileptogenic tumors.

RESULTS AND CONCLUSION

The outcomes on the Engel scale were as follows: in 27 patients with surgical intervention without ECoG: class I - 9 patients, class II - 7 patients, class III - 5 patients, class IV - 6 patients and in 25 patients operated with ECoG: class I - 19 patients, class II - 4 patients and class III - 2 patients. The significant difference (p<0.01) between I+II Engel classes in comparison with III+IV Engel classes in operated patients demonstrated the necessity of ECoG during surgery in the resection of supratentorial brain tumors in patients with symptomatic epilepsy.

Extent of Resection and Residual Tumor Thresholds for Postoperative Total Seizure Freedom in Epileptic Adult Patients Harboring a Supratentorial Diffuse Low-Grade Glioma

BACKGROUND

Epileptic seizures impair quality of life in diffuse low-grade glioma (DLGG) patients. Tumor resection significantly impacts postoperative seizure control, but the precise extent of resection (EOR) required for optimal seizure control is not clear yet.

OBJECTIVE

To identify the EOR and residual tumor volume that correlated to postoperative seizure control, defined as a total seizure freedom (Class 1A in reference to Engel classification system) with and without antiepileptic drugs in patients undergoing surgical resection of supratentorial DLGG.

METHODS

A retrospective review was conducted of all patients who underwent first-line surgical resection of supratentorial DLGG who presented with preoperative seizures without adjuvant oncological treatment. EOR and residual tumor volume were quantified from pre- and post-operative magnetic resonance imagings. Receiver operating characteristic curves were plotted to determine the EOR and residual tumor volume that corresponded to optimal postoperative seizure control.

RESULTS

Of the 346 included patients, 65.5% had controlled seizures postoperatively, with higher age at resection (adjusted OR per unit, 1.03 [95% confidence interval:1.01-1.06], P = .043) and higher percentage of resection (adjusted OR per unit, 1.02 [95% confidence interval:1.00-1.03], P < .001) found as independent predictors of postoperative seizure control. Optimal EOR was ≥91% and optimal residual tumor volume was ≤19 cc to improve postoperative seizure control.

CONCLUSION

Postoperative seizure control is more likely when EOR is ≥91% and/or when residual tumor volume is ≤19 cc in supratentorial DLGG gliomas who present with seizures. Resected peritumoral cortex should, however, be taken into account in future studies.

Epilepsy surgery for a patient with neurofibromatosis type 1 concomitant with moyamoya syndrome

BACKGROUND

Epilepsy associated with neurocutaneous disorders is well known, and the prevalence of epilepsy among patients with neurofibromatosis type 1 (NF1) ranges from 4% to 13%. However, epilepsy surgery for patients with NF1 is not commonly performed.

CASE DESCRIPTION

We report the case of a patient with medically intractable mesial temporal lobe epilepsy (mTLE) concomitant NF1 and moyamoya syndrome (MMS) who had already undergone bilateral superficial temporal artery-middle cerebral artery anastomosis at 17 years old. As the standard temporal approach was unavailable, we evaluated the patient with neurologists, radiologists, neurosurgeons and neuropsychologists to identify the safest trajectory for epilepsy surgery. The patient underwent the right selective amygdala hippocampectomy from the posterior auricle part at 32 years old and obtained freedom from seizures.

CONCLUSION

To the best of our knowledge, this represents the first surgical case report for mTLE concomitant with NF1 and MMS.

Focused review on seizures caused by meningiomas

BACKGROUND

Meningiomas belong to the most common intracranial neoplasms in adults. One of the most common symptoms patients with meningioma experience is seizures. However, it remains unclear whether prophylactic preoperative anticonvulsant treatment is worthwhile. Furthermore, it is not clear which patients are likely to experience seizures in the course of the disease. In recent years, many studies and meta-analyses addressed this question with particular contradictory results. Therefore, we aimed to identify the most important risk factors for seizures in patients with meningiomas.

METHODS

For the search terms "meningioma and seizure", "meningioma and epilepsy", and "Simpson and seizure" Medline query identified 865 articles. After applying inclusion and exclusion criteria, 20 papers were chosen for further study. The papers were analyzed for all risk factors for pre- and postoperative risk factors for seizures.

RESULTS

Preoperative seizures were mostly associated with extensive brain edema, localization, and bigger tumor size. Even though data were sometimes very contradictory, higher postoperative seizure rate in patients with meningioma was associated with distinct localizations, preoperative seizures, tumor size, brain edema, extent of resection, tumor recurrence, and new neurological deficits. There were no randomized trials showing a prophylactic effect of anticonvulsant drugs.

CONCLUSIONS

There are relevant risk factors for seizures in patients with meningioma. There is the need for a double blind randomized trial for the prophylactic use of antiepileptic drugs (AEDs).

Efficacy of levetiracetam compared with phenytoin in prevention of seizures in brain injured patients: A meta-analysis

BACKGROUND

Early and/or late onset in patients with brain injury (BI) is associated with a poorer prognosis, and phenytoin (PHT) is standard of care to prevent seizures. Levetiracetam (LEV), an alternative antiepileptic drug, is associated with less cognitive disruption. The purpose of this study was to evaluate the safety and efficacy of LEV in the prevention of brain traumatic seizures with the standard drug PHT.

METHODS

Search the publications on comparison the safety and efficacy of LEV against the standard agent PHT in prevention of traumatic seizures in BI to January 2018. After rigorous reviewing on quality, the data were extracted from eligible trials. All trials analyzed the summary hazard ratios of the endpoints of interest.

RESULTS

LEV was found not more effective than PHT in terms of overall seizure (odds ratio [OR] = 0.73; 95% confidence interval [CI] = 0.51-1.05; P = .09), and late seizure (OR = 0.64; 95% CI = 0.34-1.19; P = .16) occurrence. However, there is significant difference in terms of early seizure (OR = 0.63; 95% CI = 0.40-0.99; P = .04). Moreover, there were no significant differences in terms of mortality (OR = 0.67; 95% CI = 0.43-1.05; P = .08), or side effects (OR = 1.31; 95% CI = 0.80-2.15; P = .29) between groups.

CONCLUSION

The meta-analysis showed that LEV prevention of seizures was associated with early seizure rates that were lower than the PHT-prolonged course of treatment. There is no statistically significant difference in the efficacy and safety profile of PHT and LEV in cases of traumatic BI.

Diffuse Low-Grade Glioma-Related Epilepsy

The World Health Organization classifies diffuse low-grade gliomas (DLGGs) are highly epileptogenic primary brain tumors; epileptic seizures occur in more than 90% of cases. Epileptic seizures and drug resistance progress during the course of DLGGs. The glioma-related epileptogenic mechanisms are multifactorial; epileptogenic foci lie within the infiltrated peritumoral neocortex. A short seizure duration before surgery and a large extent of resection are the main predictors of postoperative seizure control in DLGGs. A supratotal resection of a DLGG can improve postoperative seizure control. Epileptic seizure at diagnosis positively affects DLGGs malignant transformation and overall survival.

Aberrant neuronal differentiation is common in glioma but is associated neither with epileptic seizures nor with better survival

The mechanisms of glioma-associated seizures (GAS) have yet to be fully elucidated. Proneural subtype, isocitrate dehydrogenase 1 (IDH1) mutations, and epileptic seizures are closely associated suggesting that aberrant neuronal differentiation contributes to glioma-associated seizures. In a population-based cohort (n = 236), lack of stem cell marker expression (nestin, musashi) was significantly associated with IDH1 mutations and GAS at diagnosis. In vitro data suggested an association of IDH1 mutations and a more differentiated phenotype. Out of eight glioma stem cell (GSC) lines, seven revealed positivity for the synaptic marker protein synaptophysin. Three had synapse-like structures identified by electron microscopy and were either vGlut1 (glutamatergic) or GAD67 (GABAergic) positive. In vivo, >10% synaptophysin-positive tumour cells were present in >90% of all gliomas. Synaptophysin expression was associated with proneural subtype and vGlut1 expression, suggesting that most synapse-like structures in glioma are glutamatergic. However, we found null associations between vGlut1 protein/mRNA expression and survival, GAS at onset, development of GAS after resection, and refractory GAS. Synapse-like structures were neither functional nor activated by spontaneous action potentials or cellular networks. Thus, aberrant neuronal differentiation including glutamatergic synapse-like structures is detectable in glioma but is associated neither with epileptic seizures nor with better survival.

BRAF somatic mutation contributes to intrinsic epileptogenicity in pediatric brain tumors

Pediatric brain tumors are highly associated with epileptic seizures¹. However, their epileptogenic mechanisms remain unclear. Here, we show that the oncogenic BRAF somatic mutation p.Val600Glu (V600E) in developing neurons underlies intrinsic epileptogenicity in ganglioglioma, one of the leading causes of intractable epilepsy². To do so, we developed a mouse model harboring the BRAF^V600E somatic mutation during early brain development to reflect the most frequent mutation, as well as the origin and timing thereof. Therein, the BRAF^V600E mutation arising in progenitor cells during brain development led to the acquisition of intrinsic epileptogenic properties in neuronal lineage cells, whereas tumorigenic properties were attributed to high proliferation of glial lineage cells. RNA sequencing analysis of patient brain tissues with the mutation revealed that BRAF^V600E-induced epileptogenesis is mediated by RE1-silencing transcription factor (REST), which is a regulator of ion channels and neurotransmitter receptors associated with epilepsy. Moreover, we found that seizures in mice were significantly alleviated by an FDA-approved BRAF^V600E inhibitor, vemurafenib, as well as various genetic inhibitions of Rest. Accordingly, this study provides direct evidence of a BRAF somatic mutation contributing to the intrinsic epileptogenicity in pediatric brain tumors and suggests that BRAF and REST could be treatment targets for intractable epilepsy.

Levetiracetam enhances the temozolomide effect on glioblastoma stem cell proliferation and apoptosis

Background

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor in which cancer cells with stem cell-like features, called cancer stem cells (CSCs), were identified. Two CSC populations have been previously identified in GBM, one derived from the GBM area called enhanced lesion (GCSCs) and the other one from the brain area adjacent to the tumor margin (PCSCs) that greatly differ in their growth properties and tumor-initiating ability. To date the most effective chemotherapy to treat GBM is represented by alkylating agents such as temozolomide (TMZ), whose activity can be regulated by histone deacetylases (HDACs) inhibitors through the modulation of O6-methylguanine-DNA methyltransferase (MGMT) expression. Levetiracetam (LEV), a relatively new antiepileptic drug, modulates HDAC levels ultimately silencing MGMT, thus increasing TMZ effectiveness. However, an improvement in the therapeutic efficacy of TMZ is needed.

Methods

Cell proliferation was investigated by BrdU cell proliferation assay and by Western Blot analysis of PCNA expression. Apoptosis was evaluated by Western Blot and Immunofluorescence analysis of the cleaved Caspase-3 expression. MGMT and HDAC4 expression was analyzed by Western Blotting and Immunofluorescence. Statistical analysis was performed using the Student's t test and Mann-Whitney test.

Results

Here we evaluated the effect of TMZ on the proliferation rate of the IDH-wildtype GCSCs and PCSCs derived from six patients, in comparison with the effects of other drugs such as etoposide, irinotecan and carboplatin. Our results demonstrated that TMZ was less effective compared to the other agents; hence, we verified the possibility to increase the effect of TMZ by combining it with LEV. Here we show that LEV enhances the effect of TMZ on GCSCs proliferation (being less effective on PCSCs) by decreasing MGMT expression, promoting HDAC4 nuclear translocation and activating apoptotic pathway.

Conclusions

Although further studies are needed to determine the exact mechanism by which LEV makes GBM stem cells more  sensitive to TMZ, these results suggest that the clinical therapeutic efficacy of TMZ in GBM might be enhanced by the combined treatment with LEV.

Medical Complications of Brain Tumors

PURPOSE OF REVIEW

This article discusses common and emergent medical complications encountered in patients with primary brain tumors.

RECENT FINDINGS

Clinical studies and systematic reviews published in recent years have improved knowledge regarding the incidence of neurologic and medical complications occurring in patients with primary brain tumors. Studies in tumor-related epilepsy and venous thromboembolism provide data for the clinician to make evidence-based decisions about perioperative management, prophylaxis, and therapy. Patients with brain tumors experience unique toxicities related to novel drugs and chemotherapeutics that result in hematologic, infectious, and endocrine disorders. Recent work that has focused on quality of life in patients with brain tumors highlights the importance of good supportive care and optimal medical management of neurobehavioral symptoms and late complications of treatment.

SUMMARY

A thorough understanding of the variety of medical and neurologic complications in patients with primary brain tumors improves the clinician's ability to quickly recognize and manage common and urgent conditions.

Seizure outcomes of supratentorial brain tumor resection in pediatric patients

Background

This study aims to identify the prevalence of and risk factors for seizure development after supratentorial brain tumor resection in pediatric patients. This could be used to guide the postoperative management and usage of anti-epileptic drugs (AEDs).

Methods

Retrospective study was conducted for patients between 0 and 21 years with supratentorial tumor resection between 2005 and 2015 at a single institution.

Results

Two hundred patients (114 males/86 females) were identified. Median age at resection (±SD) was 9.025 ± 5.720 years and mean follow-up was 4 ± 2 years. Resection was gross total in 82 patients (41%) and partial in 118 patients (59%); 66 patients (33%) experienced preoperative seizures, and 67 patients (34%) experienced postoperative seizures; 18 patients (27%) had early seizures, and 49 patients (73%) had late seizures. Univariate analysis identified risk factors for postoperative seizures as: preoperative seizures (P < 0.001), age less than 2 years (P = 0.003), temporal location (P < 0.001), thalamic location (P = 0.017), preoperative hyponatremia (P = 0.017), World Health Organization grade (P = 0.008), and pathology (P = 0.005). Multivariate regression identified 5 robust risk factors: temporal location (odds ratio [OR] 4.7, 95% CI: 1.7-13.3, P = 0.003), age <2 years (OR 3.9, 95% CI: 1.0-15.4; P = 0.049), preoperative hydrocephalus (OR 3.8, 95% CI: 1.5-9.4; P = 0.005), preoperative seizure (OR 2.8, 95% CI: 1.2-6.5; P = 0.016) and parietal location (OR 0.25, 95% CI: 0.06-0.99; P = 0.049). Extent of resection did not correlate with seizure development (P > 0.05).

Conclusions

This study reveals 5 risk factors for postoperative seizures after resection of supratentorial tumors. These factors should be considered in postoperative management of these patients.