Factors of surgical outcome in tumoural epilepsy

Objectives. The purposes of the study were the assessment of the role of su rgery in the suppression of epilepsy due to low-grade primitive cerebral tu mours and the search for factors relevant to the surgical outcome. Patients and Methods Forty-eight patients with epilepsy due to low-grade su pratentorial cerebral tumours were considered. They presented drug-resistan t daily to monthly seizures since for least one year (mean 7 yrs). Twenty-f our patients underwent a combined tumour and epileptogenic zone resection ( "epilepsy surgery") and 24 tumour resection alone ("lesionectomy"). The sur gical outcome was evaluated two years after surgery. Several variables rela ted to the characteristics of the epilepsy, the tumour and surgery, were co nsidered for a possible association with the outcome. Statistical analyses were performed. Results. Seizure freedom, including aura, was obtained in 35 patients (72.9 %). Mild permanent complications occurred in 6 cases. Seizure suppression w as significantly associated with complete tumour resection (post-surgical C T or MRI) and relatively low presurgical seizure frequency; it was also rel ated, though not significantly, to small tumour size and histological grade I. The surgical outcome was only slightly better following "epilepsy surge ry" than "lesionectomy". However: i) the extent of tumour resection was not relevant regarding the "epilepsy surgery" outcome, while significantly inf luencing the outcome after "lesionectomy"; ii) the presurgical frequency of seizures and, to a less extent, the tumour size, had a higher influence on the outcome after "lesionectomy". Conclusion. Long-lasting and drug-resistant epilepsy due to cerebral tumour s can be suppressed surgically in the majority of cases. The extent of tumo ur resection and the frequency of the seizures are the most relevant progno stic factors. Both "epilepsy surgery" and "lesionectomy" can provide good r esults. However, the two approaches should not be regarded as interchangeab le: a choice of the approach based on the characteristics of seizures and o f the tumour appears relevant to improve the surgical prognosis.