THE COURSE OF SEIZURE DISORDERS IN PATIENTS WITH MALIGNANT GLIOMAS

Objective: To describe the morbidity associated with seizures and the efficacy of anticonvulsant therapy in adult patients with malignant gl iomas (MGs). Study Design: A retrospective review of charts was perfor med to determine the occurrence of seizures at diagnosis, the frequenc y and character of subsequent seizures, and the use and toxic side eff ects of anticonvulsants. Patients: Sixty-five consecutive adult patien ts with supratentorial MGs who were examined in the neurooncology clin ic at a university medical center were studied. The diagnosis was glio blastoma in 47 of the patients, and it was anaplastic astrocytoma in 1 8 patients. The mean age of the patients was 49.5 years. The median Ka rnofsky status score was 80. The median survival was 18 months. Result s: Twenty-nine patients presented with seizures, and 21 of these had s ubsequent leg, ''recurrent'') seizures while they were receiving antic onvulsant therapy. Ten of 36 patients who were free of seizures at dia gnosis experienced seizures after diagnosis leg, ''late onset'') while they were being treated with anticonvulsants, including five patients who had single seizures. Long-term seizure frequency in excess of one per month was observed in 13 patients. Ten patients had episodes of p artial motor status epilepticus. Most recurrent and late-onset seizure s occurred despite therapeutic anticonvulsant levels, and without evid ence of tumor progression. Rash associated with anticonvulsants was ob served in 26% of the patients. Other clinically important toxic side e ffects were observed in 14% of the patients who were receiving long-te rm anticonvulsant therapy. Conclusions: Seizures contributed substanti ally to the neurologic morbidity of MGs in at least 25% of these patie nts. The occurrence of seizures at diagnosis was a strong predictor of subsequent seizures, and in many patients, seizures proved to be refr actory to standard anticonvulsant therapy. Long-term anticonvulsant to xic side effects are relatively common in patients with MGs. The use o f long-term seizure prophylaxis for patients with MGs who are free of seizures at presentation is not clearly beneficial and should be studi ed in a prospective trial.