Epilepsy is common in patients with
brain tumors. Usually, an epileptic seizure is the presenting sign of the cerebral lesion but late
seizures may also occur. The
tumors type and their locations are determining factors that significantly influence seizure frequency.
Brain tumors with a high risk for
epilepsy are developmental
tumors, slow-growing
tumors (low-grade
gliomas), hemorrhagic
tumors and multiple
metastases.
Seizures associated with
brain tumors are sometimes difficult to treat. This relative drug-resistance may be attributed to several factors: the
tumor development, modifications of
tumor and peritumor tissues, oncologic treatments. Genetic factors also play an important role and
multidrug-resistance proteins associated with
brain tumors can be a major cause of
epilepsy refractoriness. The choice of the
antiepileptic treatment is very important and must take into account individual factors but, in general, the first-line prescription of
enzyme-inducing
antiepileptic drugs, especially
phenytoin, is not mandatory. Given the frequency of
epilepsy in patients with
brain tumors, a prophylactic
antiepileptic treatment could be warranted; but, unfortunately, no study has proven the effect of
antiepileptic drugs as prophylactic treatment and a consensus statement from the AAN recommends not using
antiepileptic drugs routinely as prophylaxis in patients with
brain tumors. Nevertheless, these recommendations are based on studies performed with conventional
antiepileptic drugs. Further randomized large cohort studies seem thus required to assess the effectiveness of new
antiepileptic drugs to prevent and cure
epilepsy in patients with
brain tumors.