Epilepsy in cerebral glioma: timing of appearance and histological correlations

A prospective study of patients with glioma was carried out. Special attention was paid to the first seizure, to the histology, and to the efficacy and prophylactic role of antiepileptic drugs (AEDs). Prognostic factors were analyzed.

Between February 1st 2004 and April 1st 2006 patients who underwent surgical treatment at the Neurosurgery Department of Bolzano for primary or recurrent glioma were prospectively followed until April 1st 2007. Seizures at onset occurring in the absence of interictal epileptiform abnormalities were regarded as remote symptomatic seizures and not treated.

Sixty-four individuals were registered in the study; epilepsy diagnosis was made in 27 cases and in 24 of these seizures were the onset symptom. The correlation with histological grading showed that seizures were more frequent in low-grade glioma and in secondary glioblastoma. Although epilepsy was less frequent in high-grade glioma, in these patients seizures were more difficult to control. Poor seizure control was associated with motor and sensitive focal seizures and presence of neurological deficit. Patients without epilepsy and not taking AEDs never developed seizures during the follow-up.

Our study clearly shows that epilepsy is more frequent in low-grade gliomas but seizures are more difficult to control in high-grade gliomas. In both cases seizures are a quite exclusive symptom at the onset that never appears during the stable course of the disease. Amongst glioblastoma multiforme (GBM), epilepsy is more frequent in GBM developing through progression from low-grade astrocitoma. Moreover, our study strongly indicates that the prophylactic use of AEDs in glioma is not justified.