Outcomes after discontinuation of antiepileptic drugs after surgery in patients with low grade brain tumors and meningiomas

Patient-Centered Management of Brain Tumor-Related Epilepsy

PURPOSE OF REVIEW

Brain tumor-related epilepsy is a heterogenous syndrome involving variability in incidence, timing, pathophysiology, and clinical risk factors for seizures across different brain tumor pathologies. Seizure risk and disability are dynamic over the course of disease and influenced by tumor-directed treatments, necessitating individualized patient-centered management strategies to optimize quality of life.

RECENT FINDINGS

Recent translational findings in diffuse gliomas indicate a dynamic bidirectional relationship between glioma growth and hyperexcitability. Certain non-invasive measures of hyperexcitability are correlated with survival outcomes, however it remains uncertain how to define and measure clinically relevant hyperexcitability serially over time. The extent of resection, timing of pre-operative and/or post-operative seizures, and the likelihood of tumor progression are critical factors impacting the risk of seizure recurrence. Newer anti-seizure medications are generally well-tolerated with similar efficacy in this population, and several rapid-onset seizure rescue agents are in development and available. Seizures in patients with brain tumors are strongly influenced by the underlying tumor biology and treatment. An improved understanding of the interactions between tumor cells and the spectrum of hyperexcitability will facilitate targeted therapies. Multidisciplinary management of seizures should occur with consideration of tumor-directed therapy and prognosis, and anti-seizure medication decision-making tailored to the individual priorities and quality of life of the patient.

Discontinuation of Antiseizure Medications in Patients With Brain Tumors

Patients with brain tumors will experience seizures during their disease course. While providers can use antiseizure medications to control these events, patients with brain tumors can experience side effects, ranging from mild to severe, from these medications. Providers in subspecialties such as neurology, neuro-oncology, neurosurgery, radiation oncology, and medical oncology often work with patients with brain tumor to balance seizure control and the adverse toxicity of antiseizure medications. In this study, we sought to explore the problem of brain tumor-related seizures/epilepsy in the context of how and when to consider antiseizure medication discontinuation. Moreover, we thoroughly evaluate the literature on antiseizure medication discontinuation for adult and pediatric patients and highlight recommendations relevant to patients with both brain tumors and seizures.

Brain tumor-related epilepsy management: A Society for Neuro-oncology (SNO) consensus review on current management

Tumor-related epilepsy (TRE) is a frequent and major consequence of brain tumors. Management of TRE is required throughout the course of disease and a deep understanding of diagnosis and treatment is key to improving quality of life. Gross total resection is favored from both an oncologic and epilepsy perspective. Shared mechanisms of tumor growth and epilepsy exist, and emerging data will provide better targeted therapy options. Initial treatment with antiseizure medications (ASM) in conjunction with surgery and/or chemoradiotherapy is typical. The first choice of ASM is critical to optimize seizure control and tolerability considering the effects of the tumor itself. These agents carry a potential for drug-drug interactions and therefore knowledge of mechanisms of action and interactions is needed. A review of adverse effects is necessary to guide ASM adjustments and decision-making. This review highlights the essential aspects of diagnosis and treatment of TRE with ASMs, surgery, chemotherapy, and radiotherapy while indicating areas of uncertainty. Future studies should consider the use of a standardized method of seizure tracking and incorporating seizure outcomes as a primary endpoint of tumor treatment trials.

Patterns of Antiseizure Medication Use Following Meningioma Resection: A Single-Institution Experience

OBJECTIVE

To investigate antiseizure medication (ASM) practice behavior for patients who present with seizures before meningioma resection and to review postoperative ASM management.

METHODS

A retrospective study was performed of 112 consecutive patients with meningiomas who underwent resection at a single institution between October 2016 and January 2020. Data were collected through detailed chart review.

RESULTS

Of 112 patients, 35 (31%) had a preoperative seizure, and 43 (38%) were prescribed a preoperative ASM. At discharge, 96 patients (86%) were prescribed an ASM, most often 1000 mg daily of levetiracetam (64%, 61/96) and less often higher doses of levetiracetam or other ASMs. By the 6-month postoperative visit, 55 patients (49%) were taking at least 1 ASM, most commonly levetiracetam monotherapy (65%) at 500 mg twice daily (47%). This number further decreased to 45 (40%) patients by 1-year follow-up and 36 (32%) patients by last-known follow-up. By last follow-up (median 27.3 months; range 5.4-57.4 months), 24 patients (21%) had experienced a postoperative seizure, and 36 patients (32%) were never able to discontinue ASMs. Of patients remaining on levetiracetam monotherapy, only 36% remained on levetiracetam 500 mg twice daily.

CONCLUSIONS

Approximately two thirds (68%) of patients who underwent surgical resection of meningioma were eventually able to completely discontinue their postoperative ASM regimen. However, nearly one third (32%) of patients required long-term ASM management. Levetiracetam monotherapy was the most common ASM prescribed during the postoperative period, and the proportion of patients requiring either higher doses of levetiracetam or alternative ASMs increased over time.

Impact of timing of antiseizure medication withdrawal on seizure recurrence in glioma patients: a retrospective observational study

BACKGROUND

Withdrawal of antiseizure medication treatment (ASM) can be considered after completion of antitumour treatment in glioma patients who no longer suffer from seizures. We compared the risk for recurrent seizures after ASM withdrawal between patients with short-term, medium-term versus long-term seizure freedom after antitumour treatment.

METHODS

In this retrospective observational study, the primary outcome was time to recurrent seizure, from the starting date of no ASM treatment up to 36 months follow-up. Cox proportional hazards models were used to study the effect of risk factors on time to recurrent seizure. Stratification was done with information known at baseline. Short-term seizure freedom was defined as ≥ 3 months, but < 12 months; medium-term as 12-24 months; and long-term as ≥ 24 months seizure freedom from the date of last antitumour treatment.

RESULTS

This study comprised of 109 patients; 31% (34/109) were in the short-term, 29% (32/109) in the medium-term, and 39% (43/109) in the long-term group. A recurrent seizure was experienced by 47% (16/34) of the patients in the short-term, 31% (10/32) in the medium-term, and 44% (19/43) in the long-term group. Seizure recurrence risk was similar between patients in the short-term group as compared to the medium-term (cause-specific adjusted hazard ratio [aHR] = 0.65 [95%CI = 0.29-1.46]) and long-term group (cause-specific aHR = 1.04 [95%CI = 0.52-2.09]).

CONCLUSIONS

Seizure recurrence risk is relatively similar between patients with short-term, medium-term, and long-term seizure freedom after completion of antitumour treatment.

The clinical and genomic features of seizures in meningiomas

Meningiomas are the most common central nervous system tumors. Although these tumors are extra-axial, a relatively high proportion (10%-50%) of meningioma patients have seizures that can substantially impact the quality of life. Meningiomas are believed to cause seizures by inducing cortical hyperexcitability that results from mass effect and cortical irritation, brain invasion, or peritumoral brain edema. In general, meningiomas that are associated with seizures have aggressive features, with risk factors including atypical histology, brain invasion, and higher tumor grade. Somatic NF2 mutated meningiomas are associated with preoperative seizures, but the effect of the driver mutation is mediated through atypical features. While surgical resection is effective in controlling seizures in most patients with meningioma-related epilepsy, a history of seizures and uncontrolled seizures prior to surgery is the most significant predisposing factor for persistent postoperative seizures. Subtotal resection (STR) and relatively larger residual tumor volume are positive predictors of postoperative seizures. Other factors, including higher WHO grade, peritumoral brain edema, and brain invasion, are inconsistently associated with postoperative seizures, suggesting they might be crucial in the development of an epileptogenic focus, but do not appear to play a substantial role after seizure activity has been established. Herein, we review and summarize the current literature surrounding meningioma-related epilepsy and underscore the interaction of multiple factors that relate to seizures in patients with meningioma.

Management of epilepsy in brain tumor patients

PURPOSE OF REVIEW

A concise review of recent findings in brain tumor-related epilepsy (BTRE), with focus on the effect of antitumor treatment on seizure control and the management of antiepileptic drugs (AEDs).

RECENT FINDINGS

Isocitrate dehydrogenase mutation and its active metabolite d -2-hydroxyglutarate seem important contributing factors to epileptogenesis in BTRE. A beneficial effect of antitumor treatment (i.e. surgery, radiotherapy, and chemotherapy) on seizure control has mainly been demonstrated in low-grade glioma. AED prophylaxis in seizure-naïve BTRE patients is not recommended, but AED treatment should be initiated after a first seizure has occurred. Comparative efficacy randomized controlled trials (RCTs) are currently lacking, but second-generation AED levetiracetam seems the preferred choice in BTRE. Levetiracetam lacks significant drug-drug interactions, has shown favorable efficacy compared to valproic acid in BTRE, generally causes no hematological or neurocognitive functioning adverse effects, but caution should be exercised with regard to psychiatric adverse effects. Potential add-on AEDs in case of uncontrolled seizures include lacosamide, perampanel, and valproic acid. Ultimately, in the end-of-life phase when oral intake of medication is hampered, benzodiazepines via nonoral administration routes are potential alternatives.

SUMMARY

Management of seizures in BTRE is complex and with currently available evidence levetiracetam seems the preferred choice. Comparative efficacy RCTs in BTRE are warranted.

Prescription preferences of antiepileptic drugs in brain tumor patients: An international survey among EANO members

Background

This study aimed at investigating antiepileptic drug (AED) prescription preferences in patients with brain tumor-related epilepsy (BTRE) among the European neuro-oncology community, the considerations that play a role when initiating AED treatment, the organization of care, and practices with regard to AED withdrawal.

Methods

A digital survey containing 31 questions about prescription preferences of AEDs was set out among members of the European Association of Neuro-Oncology (EANO).

Results

A total of 198 respondents treating patients with BTRE participated of whom 179 completed the entire survey. Levetiracetam was the first choice in patients with BTRE for almost all respondents (90% [162/181]). Levetiracetam was considered the most effective AED in reducing seizure frequency (72% [131/181]) and having the least adverse effects (48% [87/181]). Common alternatives for levetiracetam as equivalent first choice included lacosamide (33% [59/181]), lamotrigine (22% [40/181]), and valproic acid (21% [38/181]). Most crucial factors to choose a specific AED were potential adverse effects (82% [148/181]) and interactions with antitumor treatments (76% [137/181]). In the majority of patients, neuro-oncologists were involved in the treatment of seizures (73% [132/181])). Other relevant findings were that a minority of respondents ever prescribe AEDs in brain tumor patients without epilepsy solely as prophylaxis (29% [53/181]), but a majority routinely considers complete AED withdrawal in BTRE patients who are seizure-free after antitumor treatment (79% [141/179]).

Conclusions

Our results show that among European professionals treating patients with BTRE levetiracetam is considered the first choice AED, with the presumed highest efficacy and least adverse effects.

Health-related quality of life in meningioma

Background. Meningiomas are the most common primary intracranial tumor in adults. Although frequently histologically benign, the clinical severity of a lesion may range from being asymptomatic to causing severe impairment of global function and well-being. The diversity of intracranial locations and clinical phenotypes poses a challenge when studying functional impairments, however, more recent attention to patient-reported outcomes and health-related quality of life (HRQOL) have helped to improve our understanding of how meningioma may impact a patient’s life.Methods. Treatment strategies such as observation, surgery, radiation, or a combination thereof have been examined to ascertain their contributions to symptoms, physical and cognitive functioning, disability, and general aspects of daily functioning.Results. This review explores the multidimensional nature of HRQOL and how patients may be influenced by meningiomas and their treatment.Conclusion. Overall, treatment of symptomatic meningiomas is associated with improved HRQOL, cognitive functioning, and seizure control while tumor size, location, histologic grade, and epileptic burden are associated with worse HRQOL.

SNO and EANO practice guideline update: Anticonvulsant prophylaxis in patients with newly diagnosed brain tumors

OBJECTIVE

To update the 2000 American Academy of Neurology (AAN) practice parameter on anticonvulsant prophylaxis in patients with newly diagnosed brain tumors.

METHODS

Following the 2017 AAN methodologies, a systematic literature review utilizing PubMed, EMBASE, Cochrane, and Web of Science databases was performed. The studies were rated based on the AAN therapeutic or causation classification of evidence (Class I-IV).

RESULTS

Thirty-seven articles were selected for final analysis. There were limited high level, Class I studies and mostly Class II and III studies. The AAN affirmed the value of these guidelines.

RECOMMENDATIONS

In patients with newly diagnosed brain tumors who have not had a seizure, clinicians should not prescribe anti-epileptic drugs (AEDs) to reduce the risk of seizures (Level A). In brain tumor patients undergoing surgery, there is insufficient evidence to recommend prescribing AEDs to reduce the risk of seizures in the peri- or postoperative period (Level C). There is insufficient evidence to support prescribing valproic acid or levetiracetam with the intent to prolong progression-free or overall survival (Level C). Physicians may consider use of levetiracetam over older AEDs to reduce side effects (Level C). There is insufficient evidence to support using tumor location, histology, grade, molecular/imaging features, when deciding whether or not to prescribe prophylactic AEDs (Level U).

Early and Late Postoperative Seizures in Meningioma Patients and Prediction by a Recent Scoring System

Simple Summary

Seizures are among the most common symptoms of meningioma patients even after surgery. This study sought to identify risk factors for early and late seizures in meningioma patients and to evaluate a modified version of a score to predict postoperative seizures on an independent cohort. The data underline that there are distinct factors identifying patients with a high risk of postoperative seizures following meningioma surgery which has been already shown before. We could further show that the high proportion of 43% of postoperative seizures occur as late seizures which are more dangerous because they may happen out of hospital. The modified STAMPE2 score could predict postoperative seizures when reaching very high scores but was not generally transferable to our independent cohort.

Abstract

Seizures are among the most common symptoms of meningioma. This retrospective study sought to identify risk factors for early and late seizures in meningioma patients and to evaluate a modified STAMPE2 score. In 556 patients who underwent meningioma surgery, we correlated different risk factors with the occurrence of postoperative seizures. A modified STAMPE2 score was applied. Risk factors for preoperative seizures were edema (p = 0.039) and temporal location (p = 0.038). For postoperative seizures preoperative tumor size (p < 0.001), sensomotory deficit (p = 0.004) and sphenoid wing location (p = 0.032) were independent risk factors. In terms of postoperative status epilepticus; sphenoid wing location (p = 0.022), tumor volume (p = 0.045) and preoperative seizures (p < 0.001) were independent risk factors. Postoperative seizures lead to a KPS deterioration and thus an impaired quality of life (p < 0.001). Late seizures occurred in 43% of patients with postoperative seizures. The small sub-cohort of patients (2.7%) with a STAMPE2 score of more than six points had a significantly increased risk for seizures (p < 0.001, total risk 70%). We concluded that besides distinct risk factors, high scores of the modified STAMPE2 score could estimate the risk of postoperative seizures. However, it seems not transferable to our cohort

Clinical and genomic factors associated with seizures in meningiomas

OBJECTIVE

The association of seizures with meningiomas is poorly understood. Moreover, any relationship between seizures and the underlying meningioma genomic subgroup has not been studied. Herein, the authors report on their experience with identifying clinical and genomic factors associated with preoperative and postoperative seizure presentation in meningioma patients.

METHODS

Clinical and genomic sequencing data on 394 patients surgically treated for meningioma at Yale New Haven Hospital were reviewed. Correlations between clinical, histological, or genomic variables and the occurrence of preoperative and postoperative seizures were analyzed. Logistic regression models were developed for assessing multiple risk factors for pre- and postoperative seizures. Mediation analyses were also conducted to investigate the causal pathways between genomic subgroups and seizures.

RESULTS

Seventeen percent of the cohort had presented with preoperative seizures. In a univariate analysis, patients with preoperative seizures were more likely to have tumors with a somatic NF2 mutation (p = 0.020), WHO grade II or III tumor (p = 0.029), atypical histology (p = 0.004), edema (p < 0.001), brain invasion (p = 0.009), and worse progression-free survival (HR 2.68, 95% CI 1.30-5.50). In a multivariate analysis, edema (OR 3.11, 95% CI 1.46-6.65, p = 0.003) and atypical histology (OR 2.00, 95% CI 1.03-3.90, p = 0.041) were positive predictors of preoperative seizures, while genomic subgroup was not, such that the effect of an NF2 mutation was indirectly mediated through atypical histology and edema (p = 0.012). Seizure freedom was achieved in 83.3% of the cohort, and only 20.8% of the seizure-free patients, who were more likely to have undergone gross-total resection (p = 0.031), were able to discontinue antiepileptic drug use postoperatively. Preoperative seizures (OR 3.54, 95% CI 1.37-9.12, p = 0.009), recurrent tumors (OR 2.89, 95% CI 1.08-7.74, p = 0.035), and tumors requiring postoperative radiation (OR 2.82, 95% CI 1.09-7.33, p = 0.033) were significant predictors of postoperative seizures in a multivariate analysis.

CONCLUSIONS

Seizures are relatively common at meningioma presentation. While NF2-mutated tumors are significantly associated with preoperative seizures, the association appears to be mediated through edema and atypical histology. Patients who undergo radiation and/or have a recurrence are at risk for postoperative seizures, regardless of the extent of resection. Preoperative seizures may indeed portend a more potentially aggressive molecular entity and challenging clinical course with a higher risk of recurrence.

Clinical Management of Diffuse Low-Grade Gliomas

Diffuse low-grade gliomas (LGG) represent a heterogeneous group of primary brain tumors arising from supporting glial cells and usually affecting young adults. Advances in the knowledge of molecular profile of these tumors, including mutations in the isocitrate dehydrogenase genes, or 1p/19q codeletion, and in neuroradiological techniques have contributed to the diagnosis, prognostic stratification, and follow-up of these tumors. Optimal post-operative management of LGG is still controversial, though radiation therapy and chemotherapy remain the optimal treatments after surgical resection in selected patients. In this review, we report the most important and recent research on clinical and molecular features, new neuroradiological techniques, the different therapeutic modalities, and new opportunities for personalized targeted therapy and supportive care.

Predicting postoperative seizure development in meningiomas - Analyses of clinical, histological and radiological risk factors

INTRODUCTION

Seizures after meningioma surgery are common, with a distinct impact on postoperative life quality. Sufficient risk factors for seizure development are sparsely known but needed to improve perioperative patient counseling and, eventually, antiepileptic treatment.

MATERIALS AND METHODS

Correlations between clinical, radiological and histological variables and the onset of new seizures following surgery for initially diagnosed cranial meningioma were retrospectively analyzed in uni- and multivariate analyses.

RESULTS

752 preoperatively seizure-naïve patients (569 females, 76 % and 183 males, 24 %) with a median age of 57 years were included. Postoperative seizures occurred in 69 cases (9 %). In univariate analyses, seizures were correlated with preoperative Karnofsky Score < 80 (OR: 1.91, 95 % CI 1.01-3.59; p = .045), convexity/parasagittal tumor location (OR: 1.77, 95 % CI 1.06-2.95; p = .030), heterogenous contrast-enhancement of the tumor (OR: 2.24, 95 % CI 1.14-4.39; p = .019) and intratumoral calcifications (OR: 3.35, 95 % CI 1.59-7.05; p = .001). Multivariable analyses revealed age at the time of surgery (OR: 1.04, 95 % CI 1.01-1.07; p = .009) and intratumoral calcifications on preoperative imaging (OR: 3.70, 95 % CI 1.73-7.92; p = .001) as risk factors for postoperative seizures. Based on multivariate analyses, a score for discrimination of patients at low (3 %), intermediate (11 %) and high risk (17 %) of postoperative seizures (AUC: 0.7, p < .001) was conducted. In subgroup analyses, postoperative hemorrhage (OR: 2.90, 95 % CI 1.13-7.46; p = .028) and hydrocephalus (OR: 3.65, 95 % CI 1.48-9.01; p = .005) were correlated with postoperative seizures.

CONCLUSION

Risk factors for postoperative seizures after meningioma surgery are sparse and can be basically taken from preoperative imaging. Among surgical complications, postoperative hemorrhage and hydrocephalus are strong seizure predictors.

Management of epilepsy in brain tumors

Epilepsy in brain tumors (BTE) may require medical attention for a variety of unique concerns: epileptic seizures, possible serious adverse effects of antineoplastic and antiepileptic drugs (AEDs), physical disability, and/or neurocognitive disturbances correlated to tumor site. Guidelines for the management of tumor-related epilepsies are lacking. Treatment is not standardized, and overall management might differ according to different specialists. The aim of this document was to provide directives on the procedures to be adopted for a correct diagnostic-therapeutic path of the patient with BTE, evaluating indications, risks, and benefits. A board comprising neurologists, epileptologists, neurophysiologists, neuroradiologists, neurosurgeons, neuro-oncologists, neuropsychologists, and patients' representatives was formed. The board converted diagnostic and therapeutic problems into seventeen questions. A literature search was performed in September-October 2017, and a total of 7827 unique records were retrieved, of which 148 constituted the core literature. There is no evidence that histological type or localization of the brain tumor affects the response to an AED. The board recommended to avoid enzyme-inducing antiepileptic drugs because of their interference with antitumoral drugs and consider as first-choice newer generation drugs (among them, levetiracetam, lamotrigine, and topiramate). Valproic acid should also be considered. Both short-term and long-term prophylaxes are not recommended in primary and metastatic brain tumors. Management of seizures in patients with BTE should be multidisciplinary. The panel evidenced conflicting or lacking data regarding the role of EEG, the choice of therapeutic strategy, and timing to withdraw AEDs and recommended high-quality long-term studies to standardize BTE care.

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.

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).

Does early postoperative drug regimen impact seizure control in patients undergoing temporal lobe resections?

OBJECTIVE

To evaluate the impact of postoperative antiepileptic drug (AED) load on seizure control in patients who underwent surgical treatment for pharmacoresistant mesiotemporal lobe epilepsy during the first two postoperative years.

PATIENTS AND METHODS

532 consecutive patients (48.7% males and 51.7% females) who underwent surgical treatment for mesiotemporal lobe epilepsy were retrospectively evaluated regarding effects of AED load on seizures control during the first 2 years following epilepsy surgery. We analyzed whether postoperative increases in postoperative AED load are associated with better seizure control in patients initially not seizure free, and if postoperative decreases in postoperative AED load would increase the risk for seizure persistence or recurrence. For statistical analyses, Fisher's exact and Wilcoxon test were applied.

RESULTS

68.9, 64.0 and 59.1% of patients were completely seizure free (Engel Ia) at 3, 12 and 24 months after surgery, respectively. Patients in whom daily drug doses were increased did not have a higher rate of seizure freedom at any of the three follow-up periods. Of 16 patients achieving secondary seizure control at 12 months after surgery, only one did so with an increase in drug load in contrast to 15 patients who experienced a running down of seizures independent of drug load increases. Decreases in drug load did not significantly increase the risk for seizure recurrence. Of postoperatively seizure free patients at 3 months after surgery in whom AED were consequently reduced, 85% remained completely seizure free at 1 year and 76% at 1 year after surgery, respectively, as opposed to 86% each when AED was not reduced (differences n.s.). Mean daily drug load was significantly lower in seizure free patients at 12 and 24 months compared to patients with ongoing seizures.

CONCLUSION

In this large patient cohort stratified to the epilepsy syndrome neither did a postoperative reduction in drug load significantly increase the risk for seizure relapse nor did increases in drug dosages lead to improved seizure control. Mean drug load was on average lower in seizure free- than non-seizure free patients at 12 and 24 months of follow-up. Secondary seizure control after initial postoperative seizures in > 90% of cases occurred as a running down, independent of an AED increase. Thus, the effect of the surgical intervention rather than the postoperative drug regimen was the key determinant for seizure control. This finding supports a curative role of temporal lobe surgery rather than an effect rendering the majority of patients' pharmacoresponsive with a critical role of the antiepileptic drug regime for seizure control.

Prevention and management of postoperative seizures in neuro-oncology

INTRODUCTION

Epilepsy related to brain tumors is often difficult to treat and may impact the quality of life. We performed a review of current recommendations for the prevention of postoperative seizures and optimizing the anti-epileptic treatment.

MATERIAL AND METHODS

Based on studies performed since 2000 we conducted the review by (1) analyzing the incidence of tumoral epilepsy and mechanisms of epileptogenicity; (2) describing the current medical and surgical strategy according to oncologic treatments; (3) discussing the management of postoperative seizures; (4) considering the drug withdrawal after oncologic therapy.

RESULTS

Epilepsy related to supra-tentorial brain tumors is frequent (40-60%) especially in low-grade gliomas, glioneuronal tumors, fronto-temporal and eloquent cortex locations. Seizures can occur as a presenting symptom or during the course of the tumor, including after surgery and oncological treatments. Maximal safe surgical resection is the more effective therapy, alone or combined with adjuvant therapy (chemotherapy, radiotherapy). Anti-epileptic drugs are not indicated for epilepsy prophylaxis in patients without seizures but only after the first seizure due to high risk of recurrence. As they may generate adverse effects and interfere with oncological treatments, the choice is based on efficacy, tolerability and potential interactions. New anti-epileptic non-enzyme-inducing drugs are recommended in first-line monotherapy in association with adjuvant oncological therapies. Enzyme-inhibiting drugs could have a favorable effect on survival. Late seizures are often related to tumor progression or recurrence. Discontinuation of anti-epileptic drugs could be considered after successful oncological treatment and a stable medical condition.

CONCLUSION

These guidelines are helpful for a rational therapy in tumoral epilepsy.

A practical guide to the use of anti-epileptic drugs by neurosurgeons

Initiation of anti-epileptic drugs is increasingly relevant to daily neurosurgical practice. Intracranial pathologies ranging from brain tumours to subarachnoid haemorrhage and traumatic brain injury are commonly associated with the subsequent development of seizures. The scope and range of anti-epileptic drugs available has increased dramatically in recent years and understanding the evidence base behind this class of drugs in addition to their interaction/side effect profiles is essential. In this review we aim to generate a practical guide for neurosurgeons regarding the use of different anti-epileptic medications in common neurosurgical conditions, including considerations for their use in pregnancy.

Cost-Utility of Video-Electroencephalography Monitoring Followed by Surgery in Adults with Drug-Resistant Focal Epilepsy in Thailand

OBJECTIVES

This study assessed whether video-electroencephalography (VEEG) monitoring followed by surgery was cost-effective in adult patients with drug-resistant focal epilepsy under Thai health care context, as compared with continued medical treatment without VEEG.

METHODS

The total cost (in Thai Baht, THB) and effectiveness (in quality-adjusted life years, QALYs) were estimated over a lifetime horizon, using a decision tree and a Markov model. Data on short-term surgical outcomes, direct health care costs, and utilities were collected from Thai patients in a specialized hospital. Long-term outcomes and relative effectiveness of the surgery over medical treatment were derived, using systematic reviews of published literature.

RESULTS

Seizure-free rates at years 1 and 2 after surgery were 79.4% and 77.8%, respectively. Costs of VEEG and surgery plus 1-year follow-up care were 216,782 THB, of which the VEEG and other necessary investigations were the main cost drivers (42.8%). On the basis of societal perspective, the total cost over a 40-year horizon accrued to 1,168,679 THB for the VEEG option, 64,939 THB higher than that for no VEEG. The VEEG option contributed to an additional 1.50 QALYs over no VEEG, resulting in an incremental cost-effectiveness ratio of 43,251 THB (USD 1236) per 1 QALY gained. Changes in key parameters had a minimal impact on the incremental cost-effectiveness ratio. Accounting for uncertainty, there was an 84% probability that the VEEG option was cost-effective on the basis of Thailand's cost-effective threshold of 160,000 THB/QALY.

CONCLUSIONS

For patients with drug-resistant epilepsy, VEEG monitoring followed by epilepsy surgery was cost-effective in Thailand. Therefore it should be recommended for health insurance coverage.

The withdrawal of antiepileptic drugs in patients with low-grade and anaplastic glioma

INTRODUCTION

The withdrawal of antiepileptic drugs (AEDs) in World Health Organization (WHO) grade II-III glioma patients with epilepsy is controversial, as the presence of a symptomatic lesion is often related to an increased risk of seizure relapse. However, some glioma patients may achieve long-term seizure freedom after antitumor treatment, raising questions about the necessity to continue AEDs, particularly when patients experience serious drug side effects. Areas covered: In this review, we show the evidence in the literature from 1990-2016 for AED withdrawal in glioma patients. We put this issue into the context of risk factors for developing seizures in glioma, adverse effects of AEDs, seizure outcome after antitumor treatment, and outcome after AED withdrawal in patients with non-brain tumor related epilepsy. Expert commentary: There is currently scarce evidence of the feasibility of AED withdrawal in glioma patients. AED withdrawal could be considered in patients with grade II-III glioma with a favorable prognosis, who have achieved stable disease and long-term seizure freedom. The potential benefits of AED withdrawal need to be carefully weighed against the presumed risk of seizure recurrence in a shared decision-making process by both the clinical physician and the patient.

Epilepsy in glioma patients: mechanisms, management, and impact of anticonvulsant therapy

Seizures are a well-recognized symptom of primary brain tumors, and anticonvulsant use is common. This paper provides an overview of epilepsy and the use of anticonvulsants in glioma patients. Overall incidence and mechanisms of epileptogenesis are reviewed. Factors to consider with the use of antiepileptic drugs (AEDs) including incidence during the disease trajectory and prophylaxis along with considerations in the selection of anticonvulsant use (ie, potential side effects, drug interactions, adverse effects, and impact on survival) are also reviewed. Finally, areas for future research and exploring the pathophysiology and use of AEDs in this population are also discussed.

Intracranial meningiomas and seizures: a review of the literature

BACKGROUND

Seizures are a common manifestation of brain tumors, but literature on the incidence of seizures before and after surgery for meningiomas is limited, and principles for use of antiepileptic drugs (AEDs) are controversial.

METHODS

This review is based on a MEDLINE search for articles from 1994 to 2014 describing intracranial meningioma and seizures or epilepsy, and AEDs treatment during and after surgery.

RESULTS

Up to 40 % of patients with symptomatic meningiomas present with seizures before operation. Tumor removal usually results in seizure control, but around 20 % of patients continue to have or develop new-onset seizures after surgery. Risk factors for seizures after surgery include preoperative seizures, tumor location, and extent of tumor removal. There are no solid data to support routine pre- or postoperative AED prophylaxis in seizure-free patients, and the decision to treat and the selection of AEDs should follow the general principles of treatment of focal epilepsies.

CONCLUSIONS

Seizures are a common manifestation of meningiomas, but about 80 % patients with preoperative seizures can be seizure free after tumor removal. Prospective controlled AED trials specifically on meningioma patients are much needed.

What is New in the Management of Epilepsy in Gliomas?

OPINION STATEMENT

Seizures represent a common symptom in low- and high-grade gliomas. Tumor location and histology influence the risk for epilepsy. Some molecular factors (BRAF V 600E mutations in glioneuronal tumors and IDH1/2 mutations in diffuse grade II and III gliomas) are molecular factors that are relevant for diagnosis and prognosis and have been associated with the risk of epilepsy as well. Glutamate plays a central role in epileptogenicity and growth of glial and glioneuronal tumors, based on the release of glutamate from tumor cells that enhances excitotoxicity, and a downregulation of the inhibitory GABAergic pathways. Several potential targets for therapy have been identified, and m-TOR inhibitors have already shown activity. Gross total resection is the strongest predictor of seizure freedom in addition to clinical factors, such as preoperative seizure duration, type, and control with antiepileptic drugs (AEDs). Radiotherapy and chemotherapy with alkylating agents (procarbazine, CCNU, vincristine, temozolomide) are effective in reducing the frequency of seizures in patients with pharmacoresistant epilepsy. Newer AEDs (in particular levetiracetam and lacosamide) seem to be better tolerated than the old AEDs (phenobarbital, phenytoin, carbamazepine), but randomized clinical trials are needed to prove their superiority in terms of efficacy.

Seizure outcome after radiotherapy and chemotherapy in low-grade glioma patients: a systematic review

There is growing evidence that antitumor treatment contributes to better seizure control in low-grade glioma patients. We performed a systematic review of the current literature on seizure outcome after radiotherapy and chemotherapy and evaluated the association between seizure outcome and radiological response. Twenty-four studies were available, of which 10 described seizure outcome after radiotherapy and 14 after chemotherapy. All studies demonstrated improvements in seizure outcome after antitumor treatment. Eight studies reporting on imaging response in relation to seizure outcome showed a seizure reduction in a substantial part of patients with stable disease on MRI. Seizure reduction may therefore be the only noticeable effect of antitumor treatment. Our findings demonstrate the clinical relevance of monitoring seizure outcome after radiotherapy and chemotherapy, as well as the potential role of seizure reduction as a complementary marker of tumor response in low-grade glioma patients.

Seizures in children with dysembryoplastic neuroepithelial tumors of the brain--A review of surgical outcomes across several studies

PURPOSE

In children and adolescents, dysembryoplastic neuroepithelial tumors (DNETs) of the brain present with seizures almost 100% of the time, potentially creating significant long-term morbidity and disability despite the generally indolent course of the lesion. These tumors also tend to be quite resistant to anti-epileptic drugs which, themselves, can be associated with long-term side effects and resultant disability. Many clinicians advocate early surgical resection of these lesions, but how effective this approach is, and how aggressive tumor removal should be, continues to be debated.

METHODS

We performed a systematic review of the relevant literature to identify all reports of DNET resections in pediatric patients published over the past 20 years. In all, over 3000 MEDLINE abstracts were reviewed, ultimately resulting in 13 studies with 185 pediatric DNET patients to review.

RESULTS

Surgical resection of the lesion was effective at improving seizures in over 98% of patients and at achieving long-term seizure freedom in 86%. Surgical resection of DNETs also appeared to be quite safe, with no reported perioperative deaths and an overall rate of postoperative complications of 12%; the vast majority of these complications were transient.

CONCLUSIONS

Total gross resection of the lesion was the only factor statistically correlated with long-term seizure freedom (r = 0.63, p = 0.03). However, data remain lacking regarding whether this translates into more extensive procedures-like brain mapping and partial lobectomies-being any more effective than simple lesionectomies alone. Further research is clearly needed to address this and other crucial questions.

Withdrawal of antiepileptic drugs in glioma patients after long-term seizure freedom: design of a prospective observational study

Background

Epilepsy is common in patients with a glioma. Antiepileptic drugs (AEDs) are the mainstay of epilepsy treatment, but may cause side effects and may negatively impact neurocognitive functioning and quality of life. Besides antiepileptic drugs, anti-tumour treatment, which currently consists of surgery, radiotherapy and/or chemotherapy, may contribute to seizure control as well. In glioma patients with seizure freedom after anti-tumour therapy the question emerges whether AEDs should be continued, particularly in the case where anti-tumour treatment has been successful. We propose to explore the possibility of AED withdrawal in glioma patients with long-term seizure freedom after anti-tumour therapy and without signs of tumour progression.

Methods/Design

We initiate a prospective, observational study exploring the decision-making process on the withdrawal or continuation of AEDs in low-grade and anaplastic glioma patients with stable disease and prolonged seizure freedom after anti-tumour treatment, and the effects of AED withdrawal or continuation on seizure freedom. We recruit participants through the outpatient clinics of three tertiary referral centers for brain tumour patients in The Netherlands. The patient and the treating physician make a shared decision to either withdraw or continue AED treatment. Over a one-year period, we aim to include 100 glioma patients. We expect approximately half of the participants to be willing to withdraw AEDs. The primary outcome measures are: 1) the outcome of the shared-decision making on AED withdrawal or continuation, and decision related arguments, and 2) seizure freedom at 12 months and 24 months of follow-up. We will also evaluate seizure type and frequency in case of seizure recurrence, as well as neurological symptoms, adverse effects related to AED treatment or withdrawal, other anti-tumour treatments and tumour progression.

Discussion

This study addresses two issues that are currently unexplored. First, it will explore the willingness to withdraw AEDs in glioma patients, and second, it will assess the risk of seizure recurrence in case AEDs are withdrawn in this specific patient population. This study aims to contribute to a more tailored AED treatment, and prevent unnecessary and potentially harmful use of AEDs in glioma patients.

Levetiracetam seizure prophylaxis in craniotomy patients at high risk for postoperative seizures

Background:

The risk of developing immediate postoperative seizures in patients undergoing supratentorial brain tumor surgery without anti-epileptic drug (AED) prophylaxis is 15-20%. Patients who present with pre-operative seizures and patients with supratentorial meningioma or supratentorial low grade gliomas are at significantly higher risk. There is little data on the efficacy of levetiracetam as a prophylactic AED in the immediate postoperative period (within 7 days of surgery) in these patients.

Methods:

We conducted a retrospective chart review of 165 adult patients classified as higher risk for postoperative seizures who underwent brain tumor resection at Duke University Hospital between time May 2010 and December 2011. All patients had received levetiracetam monotherapy in doses of 1000-3000 mg/day in the immediate postoperative period.

Results:

We identified 165 patients with following tumor locations: Frontal 83 (50.3%), Temporal 37 (22.4%), Parietal 30 (18.2%), Occipital 2 (1.2%) and 13 (7.8%) with single lesions involving more than one lobe. Histology revealed: Glioma 98 (59.4%), Meningioma 57 (34.5%) and Brain Metastases 6 (3.6%). Preoperatively, 88/165 (53.3%) patients had presented with seizures. 12/165 patients (7.3%) developed clinical seizures (generalized 10, partial 2) in the immediate post-operative period. Other than somnolence in 7 patients (4.2%), no major side-effects were noted.

Conclusions:

The incidence of seizures was significantly lower in patients treated with levetiracetam (7.3%) when compared with the expected (15-20%) rate without AED prophylaxis based on the previous literature. Levetiracetam appears effective and safe for seizure prevention in patients undergoing brain tumor resection and who are at significantly higher risk of developing post-operative seizures. These findings warrant confirmation in a prospective randomized trial.

Optimizing antiepileptic drug treatment in tumoral epilepsy

Between 30% and 50% of patients with brain tumors first present with a seizure, and up to 30% more will develop seizures later. Therefore, optimal management of these patients requires a rational approach to the use of antiseizure medications. Based on current evidence, prophylactic prescription of long-term antiepileptic drugs (AEDs) in patients with brain tumors in patients who did not present with seizures is not justified. Because of the high risk of recurrence, however, AED treatment should be strongly considered after a single seizure considered to be due to a tumor. Because of the lack of well-controlled randomized trials, the decision on which AED provides the best risk-benefit ratio in the individual patient is based mostly on physician's judgment rather than sound scientific evidence. In patients who may require chemotherapy, a non-enzyme-inducing AED is preferred for initial treatment to minimize the risk of drug interactions that impact adversely on the outcome of anticancer chemotherapy. Several retrospective studies in seizure patients with glioblastoma treated with chemotherapy have provided evidence for a moderately improved survival with the use of valproic acid, possibly due to inhibition of histone deacetylase. However, valproic acid may also increase the hematologic toxicity of antineoplastic drugs, presumably by inhibiting their metabolism, and may independently impair hemostasis, which is of some concern for patients who require surgical intervention. Among newer generation AEDs, levetiracetam has a number of advantageous features, including availability of a parenteral formulation, but other agents such as gabapentin, lamotrigine, oxcarbazepine, topiramate, and zonisamide may also be considered. Potentially more effective treatments targeting specific mechanisms of epileptogenesis and ictogenesis are being investigated. Resection of the tumor, radiation therapy, or chemotherapy can bring refractory seizures under control or prolong the duration of seizure freedom, an effect that does not appear to be necessarily related to removal or shrinkage of the tumor mass. In patients with a successfully treated tumor and an overall good prognosis for long-term survival, gradual discontinuation of AEDs may be considered.