Temozolomide treatment does not affect topiramate and oxcarbazepine plasma concentrations in chronically treated patients with brain tumor-related epilepsy

Features of epileptiform activity in patients with diagnosed glioblastoma: from genetic and biochemical mechanisms to clinical aspects

Introduction. glioblastomas multiforme (grade Iv gliomas) are common and the most aggressive primary tumors of the brain with very unfavorable prognosis. In all previously published papers on epileptiform activity in glioblastomas, not enough information on encephalogram results is presented.

Aim. To study the features of epileptiform activity in patients with glioblastomas and development of a plan for further study of these patients.

Materials and methods. An analysis of articles from Elsevier, Embase, Scopus, The Cochrane Library, global Health, Russian Science Citation Index (RSCI) databases, Scholar, google, web of Science, pubmed search engines and scientific electronic library CyberLeninka was performed. materials were selected considering journal indexing system and citations, scientific novelty of the studies, statistical significance of the results. publications repeating data from previous articles or describing animal experiments were excluded from analysis.

Results. During the study, data on mechanisms of epileptiform activity pathogenesis, predisposing factors (tumor location in the temporal, frontal or parietal lobes, IDH-1 and / or IDH-2 gene mutations), treatment options in patients with glioblastomas were systemized. Additionally, and original plan of data accumulation for clinical studied taking into account limitations of the previous studies was developed to increase quality of results interpretation.

Conclusion. Epileptiform symptoms in glioblastomas negatively affect patients’ quality of life and lifespan. Currently, researchers actively search for an effective method of treatment of epileptic seizures in patients with glioblastomas. The most effective is combination of temozolomide with valproate and levetiracetam due to good control of seizure frequency, low toxicity, and pharmacological synergy between the drugs.

Tumor-related epilepsy: epidemiology, pathogenesis and management

INTRODUCTION

Seizure is a common comorbidity in patients with brain tumor. It may be the presenting symptom or develop after the tumor diagnosis. The underlying pathophysiology of brain tumor-related epilepsy remains poorly understood.

METHODS

A comprehensive literature review of Pubmed English articles from 1980-2017 was performed to summarize current knowledge and treatment options of brain tumor-related epilepsy.

RESULTS

Multiple factors have been found to contribute to tumor-related epilepsy, including tumor type, speed of tumor growth, location, and tumor burden. The underlying pathogenesis of epilepsy is not clear but perturbations in the peri-tumoral regions, both structural and cellular communications, have been implicated.

CONCLUSIONS

Surgical and medical treatments of tumor-related epilepsy remain challenging as additional factors such as the extent of surgical resection, interactions with tumor-related oncological treatments and anti-epileptic medication related side effects need to be considered.

Seizures and cancer: drug interactions of anticonvulsants with chemotherapeutic agents, tyrosine kinase inhibitors and glucocorticoids

Patients with cancer commonly experience seizures. Combined therapy with anticonvulsant drugs (AEDs) and chemotherapeutic drugs or tyrosine kinase inhibitors carries inherent risks on drug-drug interactions (DDIs). In this review, pharmacokinetic studies of AEDs with chemotherapeutic drugs, tyrosine kinase inhibitors, and glucocorticoids are discussed, including data on maximum tolerated dose, drug clearance, elimination half-life, and organ exposure. Enzyme-inducing AEDs (EIAEDs) cause about a 2-fold to 3-fold faster clearance of concurrent chemotherapeutic drugs metabolized along the same pathway, including cyclophosphamide, irinotecan, paclitaxel, and teniposide, and up to 4-fold faster clearance with the tyrosine kinase inhibitors crizotinib, dasatinib, imatinib, and lapatinib. The use of tyrosine kinase inhibitors, particularly imatinib and crizotinib, may lead to enzyme inhibition of concurrent therapy. Many of the newer generation AEDs do not induce or inhibit drug metabolism, but they can alter enzyme activity by other drugs including AEDs, chemotherapeutics and tyrosine kinase inhibitors. Glucocorticoids can both induce and undergo metabolic change. Quantitative data on changes in drug metabolism help to apply the appropriate dose regimens. Because the large individual variability in metabolic activity increases the risks for undertreatment and/or toxicity, we advocate routine plasma drug monitoring. There are insufficient data available on the effects of tyrosine kinase inhibitors on AED metabolism.

Seizures in low-grade gliomas: natural history, pathogenesis, and outcome after treatments

Seizures represent a common symptom in low-grade gliomas; when uncontrolled, they significantly contribute to patient morbidity and negatively impact quality of life. Tumor location and histology influence the risk for epilepsy. The pathogenesis of tumor-related epilepsy is multifactorial and may differ among tumor histologies (glioneuronal tumors vs diffuse grade II gliomas). 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). Epilepsy surgery may improve seizure control. 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 (levetiracetam, topiramate, lacosamide) seem to be better tolerated than the old AEDs (phenobarbital, phenytoin, carbamazepine), but there is lack of evidence regarding their superiority in terms of efficacy.

[Glioma-associated epilepsy]

BACKGROUND

Epileptic seizures are a common symptom in patients with primary brain tumours of the glioma type. The paper presents a discussion of epileptogenesis, choice of medication and follow-up of these patients.

METHOD

The article is based on a search in PubMed and selection of articles based on the authors' discretionary judgement and clinical experience with this patient group.

RESULTS

Epileptic seizures are a common symptom of glioma, particularly the low-grade types. The background to glioma-associated epilepsy is multifactorial, and the molecular biological characteristics of the tumour probably play a central part in the epileptogenesis. Effective treatment of epileptic seizures is of great importance to the quality of life of the glioma patient. Seizure frequency and the effectiveness of anti-epileptic treatment vary, and some patients require treatment with several anti-epileptic drugs. Surgical and oncological treatment of the tumour will also often reduce the frequency of seizures.

CONCLUSION

As a general rule, antiepileptics without enzyme-inducing properties and with low protein-binding should be preferred for glioma patients. This will reduce the risk of interactions with chemotherapy or steroid therapy. Patients with brain tumours are particularly vulnerable to the effects on wakefulness, moods and cognition, and this should be borne in mind in the choice of medication and in follow-up. Haematological status should be monitored particularly closely when there is concomitant use of chemotherapy and antiepileptic drugs that may affect the bone marrow function.

Brain tumor-related epilepsy

In patients with brain tumor (BT), seizures are the onset symptom in 20-40% of patients, while a further 20-45% of patients will present them during the course of the disease. These patients present a complex therapeutic profile and require a unique and multidisciplinary approach. The choice of antiepileptic drugs is challenging for this particular patient population because brain tumor-related epilepsy (BTRE) is often drug-resistant, has a strong impact on the quality of life and weighs heavily on public health expenditures.In BT patients, the presence of epilepsy is considered the most important risk factor for long-term disability. For this reason, the problem of the proper administration of medications and their potential side effects is of great importance, because good seizure control can significantly improve the patient's psychological and relational sphere. In these patients, new generation drugs such as gabapentin, lacosamide, levetiracetam, oxcarbazepine, pregabalin, topiramate, zonisamide are preferred because they have fewer drug interactions and cause fewer side effects. Among the recently marketed drugs, lacosamide has demonstrated promising results and should be considered a possible treatment option. Therefore, it is necessary to develop a customized treatment plan for each individual patient with BTRE. This requires a vision of patient management concerned not only with medical therapies (pharmacological, surgical, radiological, etc.) but also with emotional and psychological support for the individual as well as his or her family throughout all stages of the illness.

Lecture: profile of risks and benefits of new antiepileptic drugs in brain tumor-related epilepsy

In patients with brain tumor, seizures are the onset symptom in 20-40% of the patients, while a further 20-45% of the patients will present them during the course of the disease. These data are important when considering the choice of antiepileptic drugs for this particular patient population, because brain tumor-related epilepsy (BTRE) is often drug resistant, has a strong impact on the quality of life and weighs heavily on public health expenditures. In brain tumor patients, the presence of epilepsy is considered as the most important risk factor for long-term disability. For this reason, the problem of the proper administration of medications and their potential side effects is of great importance, because good seizure control can significantly improve the patient's psychological and relational sphere. In these patients, new generation drugs such as gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, topiramate, and zonisamide are preferred, because they have fewer drug interactions and cause fewer side effects. Among the recently marketed drugs, lacosamide has demonstrated promising results and should be considered as a possible treatment option. Therefore, it is necessary to develop a customized treatment plan for each patient with BTRE, whose goals are complete seizure control, minimal or no side effects, and elimination of cognitive impairment and/or psychosocial problems.

Impact of antiepileptic drugs on thrombocytopenia in glioblastoma patients treated with standard chemoradiotherapy

Epilepsy in glioblastoma multiforme (GBM) patients is common. Hematological toxicity is a potential side effect of antiepileptic drugs (AEDs) and a frequent limiting-dose effect of temozolomide (TMZ). The aim of the study was to investigate the impact of AEDs on thrombocytopenia in GBM patients treated with radiotherapy and TMZ. A cohort of 101 newly diagnosed GBM patients treated with radiotherapy and TMZ was reviewed. Clinical data, presence of seizures, AEDs use, platelet count, and accumulated TMZ dose were analyzed at each cycle. Thrombocytopenia was operationalized as a continuous platelet count and a dichotomic variable (cut-off <100.000/mm(3)). This cut-off represents the threshold beyond which TMZ treatment is modified. A linear and a probit pooled cross-sectional regression analysis were used to study the impact of age, gender, AEDs, and accumulated TMZ on thrombocytopenia. Impact of AEDs on survival was also analyzed. Thirty-five patients (35%) presented seizures at onset and 18 (27%) during follow-up. Seven (13%) needed two or more AEDs for seizure control. Grade 3-4 thrombocytopenia was found in 8%. Decrease in platelet count was related to accumulated TMZ (p < 0.001), age (p < 0.001), and valproate (p = 0.004). Platelet count <100.000/mm(3) was only associated with accumulated TMZ (p = 0.001). Recursive Partitioning Analysis prognostic class was the only variable with significant impact on survival. Valproate and age had an independent negative effect on total platelet count, although neither had an effect on critical thrombocytopenia (<100.000/mm(3)). Therefore, the systematic withhold of valproate in GBM patients might not be justified. Nevertheless, this negative effect may be taken into account especially in elderly patients.

Epilepsy and brain tumors

PURPOSE OF REVIEW

To present an overview of the recent findings in pathophysiology and management of epileptic seizures in patients with brain tumors.

RECENT FINDINGS

Low-grade gliomas are the most epileptogenic brain tumors. Regarding pathophysiology, the role of peritumoral changes [hypoxia and acidosis, blood-brain barrier (BBB) disruption, increase or decrease of neurotransmitters and receptors] are of increasing importance. Tumor-associated epilepsy and tumor growth could have some common molecular pathways. Total/subtotal surgical resection (with or without epilepsy surgery) allows a seizure control in a high percentage of patients. Radiotherapy and chemotherapy as well have a role. New antiepileptic drugs are promising, both in terms of efficacy and tolerability. The resistance to antiepileptic drugs is still a major problem: new insights into pathogenesis are needed to develop strategies to manipulate the pharmakoresistance.

SUMMARY

Epileptic seizures in brain tumors have been definitely recognized as one of the major problems in patients with brain tumors, and need specific and multidisciplinary approaches.