The medical and surgical treatment of tumoral seizures: Current and future perspectives

Abstract

Epilepsy surgery represents the main treatment option for epileptogenic brain tumors. Scalp video-electroencephalography (EEG) and magnetic resonance imaging (MRI) may suffice for defining lesional area and seizure-onset zone in discrete, surgically resectable lesions. The choice of timing for surgery requires a multidisciplinary evaluation, especially in children, when a "wait and see" approach is chosen. Discordant electroclinical and neuroimaging data and an ill-defined epileptogenic lesion require invasive investigations. A multimodal integrated approach may maximize the extent of resection while preserving cerebral function in the eloquent cortex. Radical removal of the tumor is the most important predictor of seizure freedom. Additional predictors include histopathology, age at surgery, duration of epilepsy, and seizure type. Patients with brain tumors are highly vulnerable in relation to the frequent drug-resistance of seizures, the potential interactions between antiepileptic drugs (AEDs) and chemotherapeutic agents (CMTs), and the risk of AED-related cognitive adverse events (24% higher than in the rest of the epilepsy population), in addition to brain damage resulting from tumor itself, surgery, and radiotherapy. No robust, randomized, controlled evidence supports the choice of AEDs for the treatment of seizures in patients with brain tumors. Newer AEDs have limited or no enzyme-inducing profile, prevalent renal excretion, lower plasma protein binding and, consequently, fewer interactions with CMTs. Enzyme-inducing AEDs can lower serum levels of concomitantly administered CMTs. Class I evidence suggests that in patients with brain tumors who do not have a history of seizures, prophylactic use of AEDs is neutral or ineffective.