We conducted a clinical trial to determine if prophylactic anticonvulsants in brain tumour patients (without prior seizures) reduced seizure frequency. We stopped accrual at 100 patients on the basis of the interim analysis.

One hundred newly diagnosed brain tumour patients received anticonvulsants (AC Group) or not (No AC Group) in this prospective randomized unblinded study. Sixty patients had metastatic, and 40 had primary brain tumours. Forty-six (46%) patients were randomized to the AC Group and 54 (54%) to the No AC Group. Median follow-up was 5.44 months (range 0.13 -30.1 months).

Seizures occurred in 26 (26%) patients, eleven in the AC Group and 15 in the No AC Group. Seizure-free survivals were not different; at three months 87% of the AC Group and 90% of the No AC Group were seizure-free (log rank test, p=0.98). Seventy patients died (unrelated to seizures) and survival rates were equivalent in both groups (median survival = 6.8 months versus 5.6 months, respectively; log rank test, p=0.50). We then terminated accrual at 100 patients because seizure and survival rates were much lower than expected; we would need ≥ 900 patients to have a suitably powered study.

These data should be used by individuals contemplating a clinical trial to determine if prophylactic anticonvulsants are effective in subsets of brain tumour patients (e.g. only anaplastic astrocytomas). When taken together with the results of a similar randomized trial, prophylactic anticonvulsants are unlikely to be effective or useful in brain tumour patients who have not had a seizure.