Seizure recurrence and risk factors after antiepilepsy drug withdrawal in children with brain tumors.

PURPOSE: To study seizure outcome after antiepilepsy drug (AED) withdrawal in brain tumor patients and to analyze risk factors for seizure recurrence.
METHODS: Brain tumor patients with seizures and at least one attempt at AED discontinuation were identified from the hospital database and neurology clinic records. After defining study variables, patient charts were abstracted for clinical and demographic data. Statistical analyses used log-rank tests and multivariable Cox proportional hazards models.
RESULTS: Sixty-two patients discontinued AEDs at a median time of 5.6 years from the first seizure (range, 1.2-19.6 years). Median time since AED withdrawal was 2.3 years (range, 0.4-15.1 years). Seizures recurred in 17 (27%) patients within a median time of 0.8 years (range, 0.06-7.7 years). Median seizure-free period before AED withdrawal was 1.3 years (range, 0.1-11 years). More than one tumor resection and whole-brain radiation treatment (WBRT) were associated with seizure recurrence, whereas posterior fossa tumor location was correlated with reduced seizure recurrence risk. At seizure recurrence, control was easily reestablished in 10 patients with AED reinstitution and after dose adjustment in five; two patients with poor drug compliance continue to have seizures. In 48 patients who had an EEG before AED withdrawal, spikes or slow waves did not correlate with seizure recurrence.
CONCLUSIONS: AED withdrawal can be successfully achieved in majority of carefully selected patients. WBRT and multiple tumor resections seem to be associated with an increased hazard for seizure recurrence.