Seizure prophylaxis in patients with brain tumors: a meta-analysis

To assess whether antiepileptic drugs (AEDs) should be prescribed to patients with brain tumors who have no history of seizures.

We performed a meta-analysis of randomized controlled trials (1966-2004) that evaluated the efficacy of AED prophylaxis vs no treatment or placebo to prevent seizures in patients with brain tumors who had no history of epilepsy. Summary odds ratios (ORs) were calculated using a random-effects model. Three subanalyses were performed to assess pooled ORs of seizures in patients with primary glial tumors, cerebral metastases, and meningiomas.

Of 474 articles found in the initial search, 17 were identified as primary studies. Five trials met inclusion criteria: patients with a neoplasm (primary glial tumors, cerebral metastases, and meningiomas) but no history of epilepsy who were randomized to either an AED or placebo. The 3 AEDs studied were phenobarbital, phenytoin, and valproic acid. Of the 5 trials, 4 showed no statistical benefit of seizure prophylaxis with an AED. Meta-analysis confirmed the lack of AED benefit at 1 week (OR, 0.91; 95% confidence interval [CI], 0.45-1.83) and at 6 months (OR, 1.01; 95% CI, 0.51-1.98) of follow-up. The AEDs had no effect on seizure prevention for specific tumor pathology, including primary glial tumors (OR, 3.46; 95% CI, 0.32-37.47), cerebral metastases (OR, 2.50; 95% CI, 0.25-24.72), and meningiomas (OR, 0.62; 95% CI, 0.10-3.85).

No evidence supports AED prophylaxis with phenobarbital, phenytoin, or valproic acid in patients with brain tumors and no history of seizures, regardless of neoplastic type. Subspecialists who treat patients with brain tumors need more education on this issue. Future randomized controlled trials should address whether any of the newer AEDs are useful for seizure prophylaxis.