Choice of antiepileptic drugs affects the outcome in cancer patients with seizures

The Prevalence of Seizures in Brain Metastasis Patients on Anticonvulsant Prophylaxis: A Systematic Review and Meta-Analysis

BACKGROUND

Brain metastasis (BM) prognosis is incredibly poor and is often associated with considerable morbidity. Seizures are commonly present in these patients, and their biopsychosocial impact can be dangerous. The use of antiepileptic drugs (AEDs) as primary prophylaxis remains controversial. This systematic review and meta-analysis aim to evaluate the efficacy of AED prophylaxis in patients with BM.

METHODS

MEDLINE via PubMed, Web of Science, EMBASE, and Cochrane were searched for articles pertinent to AED prophylaxis use in patients with BM. Patients with BM previously treated for cancer who were seizure naive at the time of inclusion were included. Data regarding patient characteristics, type of AED, prior treatments, and groups at a high risk of seizure were extracted. Seizure prevalence was obtained.

RESULTS

Eight studies were included in this systematic review and meta-analysis; 1902 total patients with BM were included, with 381 receiving antiepileptic prophylaxis, and 1521 receiving no prophylaxis. Although the odds of a seizure in the treatment group was found to be 1.158 times the odds of a seizure in the control group, the odds ratio was not statistically significant (t-statistic = 0.62, P value = 0.5543).

CONCLUSIONS

There was no significant difference in the odds of seizure development in control groups compared to patients receiving prophylactic antiepileptic therapy. As patients with BM present with heterogeneity in tumor characteristics and receive various treatment modalities, future research is needed to identify groups that may benefit more significantly from AED prophylaxis.

The Antiepileptic Drug Oxcarbazepine Inhibits the Growth of Patient-Derived Isocitrate Dehydrogenase Mutant Glioma Stem-like Cells

Patients diagnosed with isocitrate dehydrogenase mutant (IDH^mut) gliomas suffer frequently from seizures. Although the clinical course is less aggressive than that of its IDH wildtype counterpart, recent discoveries have shown that epileptic activity can promote tumor proliferation. However, it is not known if antiepileptic drugs confer additional value by inhibiting tumor growth. In this study, the antineoplastic properties of 20 FDA-approved antiepileptic drugs (AEDs) were tested in six patient-derived IDH^mut glioma stem-like cells (GSCs). Cell proliferation was assessed using the CellTiterGlo-3D assay. Two of the screened drugs (oxcarbazepine and perampanel) demonstrated an antiproliferative effect. A subsequent eight-point dose-response curve proved the dose-dependent growth inhibition for both drugs, but only oxcarbazepine reached an IC₅₀ value below 100 µM in 5/6 GSCs (mean 44.7 µM; range 17.4-98.0 µM), approximating the possible c_max for oxcarbazepine in patient serums. Furthermore, the treated GSC spheroids were 82% smaller (mean volume 1.6 nL vs. 8.7 nL; p = 0.01 (live/dead^TM fluorescence staining)), and the apoptotic events increased by more than 50% (caspase-3/7 activity; p = 0.006). Taken together, this drug screen of a large series of antiepileptic drugs identified oxcarbazepine as a potent proapoptotic drug in IDH^mut GSCs, which combines antiepileptic and antineoplastic properties to treat this seizure-prone patient population.

Valproate and lithium: Old drugs for new pharmacological approaches in brain tumors?

Beyond its use as an antiepileptic drug, over time valproate has been increasingly used for several other therapeutic applications. Among these, the antineoplastic effects of valproate have been assessed in several in vitro and in vivo preclinical studies, suggesting that this agent significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. During the last years various clinical trials have tried to find out if valproate co-administration could enhance the antineoplastic activity of chemotherapy in glioblastoma patients and in patients suffering from brain metastases, demonstrating that the inclusion of valproate in the therapeutic schedule causes an improved median overall survival in some studies, but not in others. Thus, the effects of the use of concomitant valproate in brain cancer patients are still controversial. Similarly, lithium has been tested as an anticancer drug in several preclinical studies mainly using the unregistered formulation of lithium chloride salts. Although, there are no data showing that the anticancer effects of lithium chloride are superimposable to the registered lithium carbonate, this formulation has shown preclinical activity in glioblastoma and hepatocellular cancers. However, few but interesting clinical trials have been performed with lithium carbonate on a very small number of cancer patients. Based on published data, valproate could represent a potential complementary therapeutic approach to enhance the anticancer activity of brain cancer standard chemotherapy. Same advantageous characteristics are less convincing for lithium carbonate. Therefore, the planning of specific phase III studies is necessary to validate the repositioning of these drugs in present and future oncological research.

Relevant pharmacological interactions between alkylating agents and antiepileptic drugs: Preclinical and clinical data

Seizures are relatively common in cancer patients, and co-administration of chemotherapeutic and antiepileptic drugs (AEDs) is highly probable and necessary in many cases. Nonetheless, clinically relevant interactions between chemotherapeutic drugs and AEDs are rarely summarized and pharmacologically described. These interactions can cause insufficient tumor and seizure control or lead to unforeseen toxicity. This review focused on pharmacokinetic and pharmacodynamic interactions between alkylating agents and AEDs, helping readers to make a rational choice of treatment optimization, and thus improving patients' quality of life. As an example, phenobarbital, phenytoin, and carbamazepine, by increasing the hepatic metabolism of cyclophosphamide, ifosfamide and busulfan, yield smaller peak concentrations and a reduced area under the plasma concentration-time curve (AUC) of the prodrugs; alongside, the maximum concentration and AUC of their active products were increased with the possible onset of severe adverse drug reactions. On the other side, valproic acid, acting as histone deacetylase inhibitor, showed synergistic effects with temozolomide when tested in glioblastoma. The present review is aimed at providing evidence that may offer useful suggestions for rational pharmacological strategies in patients with seizures symptoms undertaking alkylating agents. Firstly, clinicians should avoid the use of enzyme-inducing AEDs in combination with alkylating agents and prefer the use of AEDs, such as levetiracetam, that have a low or no impact on hepatic metabolism. Secondly, a careful therapeutic drug monitoring of both alkylating agents and AEDs (and their active metabolites) is necessary to maintain therapeutic ranges and to avoid serious adverse reactions.

Influence of Epilepsy on the Quality of Life of Patients with Brain Tumors

Epilepsy is a common consequence of brain tumors, occurring in 35 to 75% of cases. Here we evaluated the influence of epilepsy on the quality of life (QoL) of patients with malignant brain tumors (primary and metastatic) and assessed which areas of function are most affected by epilepsy and brain tumors. Sixty patients undergoing brain tumor surgery at the Neurosurgery Clinic of the 10th Military Research Hospital, Bydgoszcz, Poland (30 with epilepsy and 30 without epilepsy) were studied. Relationships between categorical variables were determined with Pearson’s chi-squared test, while continuous data were analyzed with the Mann-Whitney U-test. A p value < 0.05 was considered statistically significant. A multiple regression model was used for multivariate analysis of QoL. Patients with epilepsy more frequently reported memory disorders as a problem in their daily life. There were trends towards greater impairments in social, professional, and family life, sports and recreational activities, and daily physical activities in brain tumor patients with epilepsy rather than those without epilepsy. Higher frequency and generalized seizures significantly and adversely influenced the ability of patients to leave home and drive vehicles, but a proportion of patients with frequent, generalized seizures continued to drive regardless. Patients with generalized seizures considered the adverse effects of taking medicines as significantly disruptive. Memory disorders significantly affect the QoL of patients with epilepsy, and the importance of stopping driving must be emphasized by all healthcare professionals.

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.

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.

FoxO3a as a Positive Prognostic Marker and a Therapeutic Target in Tamoxifen-Resistant Breast Cancer

Background: Resistance to endocrine treatments is a major clinical challenge in the management of estrogen receptor positive breast cancers. Although multiple mechanisms leading to endocrine resistance have been proposed, the poor outcome of this subgroup of patients demands additional studies. Methods: FoxO3a involvement in the acquisition and reversion of tamoxifen resistance was assessed in vitro in three parental ER+ breast cancer cells, MCF-7, T47D and ZR-75-1, in the deriving Tamoxifen resistant models (TamR) and in Tet-inducible TamR/FoxO3a stable cell lines, by growth curves, PLA, siRNA, RT-PCR, Western blot, Immunofluorescence, Transmission Electron Microscopy, TUNEL, cell cycle, proteomics analyses and animal models. FoxO3a clinical relevance was validated in silico by Kaplan–Meier survival curves. Results: Here, we show that tamoxifen resistant breast cancer cells (TamR) express low FoxO3a levels. The hyperactive growth factors signaling, characterizing these cells, leads to FoxO3a hyper-phosphorylation and subsequent proteasomal degradation. FoxO3a re-expression by using TamR tetracycline inducible cells or by treating TamR with the anticonvulsant lamotrigine (LTG), restored the sensitivity to the antiestrogen and strongly reduced tumor mass in TamR-derived mouse xenografts. Proteomics data unveiled novel potential mediators of FoxO3a anti-proliferative and pro-apoptotic activity, while the Kaplan–Meier analysis showed that FoxO3a is predictive of a positive response to tamoxifen therapy in Luminal A breast cancer patients. Conclusions: Altogether, our data indicate that FoxO3a is a key target to be exploited in endocrine-resistant tumors. In this context, LTG, being able to induce FoxO3a, might represent a valid candidate in combination therapy to prevent resistance to tamoxifen in patients at risk.