Significance of chronic epilepsy in glial tumors and correlation with surgical strategies

Abstract

PURPOSE: This study was designed to compare the frequency of postoperative epilepsy in patients with acute and chronic pre-operative epilepsy and with frontal or temporal lobe glial tumors based on the hypothesis that patients with chronic epilepsy do worse. METHODS: We compared the clinical and diagnostic characteristics of the patients (n = 73) who had seizures preoperatively with those of the patients (n = 153) who did not. Among those who have had seizures preoperatively, we compared those (n = 32, chronic seizure group) who had seizures a year or more prior to surgery with those (n = 41, acute seizure group) who had seizures less than a year prior to surgery. RESULTS: Among the various factors, the frequency of benign pathology and favorable neurological state were higher in the seizure group than in the non-seizure group (p < 0.05). Complex partial seizures and low-grade tumors were frequent in the chronic seizure group, whereas simple partial seizures and high-grade tumors were frequent in the acute seizure group. Seizure-free rate was significantly higher in the acute seizure group than in the chronic group (p < 0.05). Also, the difference of seizure control rate between surgical strategies was statistically significant (p < 0.05). CONCLUSION: This study indicates that preoperative seizure duration and frequency have a close relationship with the frequency of postoperative epilepsy in patients with glial tumors. A longer duration may allow the formation of epileptogenic foci, leading to chronic epilepsy, and eventually have a negative effect on the prognosis of the patients. Factors including histopathological characteristics of the tumor, its location, seizure duration/frequency, and symptomatology should be taken into account when deciding on surgical strategies.