Motor seizures confer overall survival benefit in who grade 2 glioma

The prevalence of epilepsy in World Health Organization (WHO) grade 2 glioma is high, with seizures being the presenting symptom in 60%-90%. We explore the epidemiology of seizures in this patient population in a regional neurosurgical center.

Electronic health records of patients with histologically-proven WHO grade 2 glioma (n = 228) were reviewed between 1997 and 2021, with data collected including patient demographics, epilepsy prevalence, and seizure semiology. The influence of seizure type on overall survival was calculated using a Cox proportional hazards model.

Overall, 197 of 228 patients (86.4%) were diagnosed with epilepsy-either at presentation or during the course of their disease. Male patients were more likely than female patients to be diagnosed with epilepsy (91.1% vs 77.1%, p = .003) and, in those with epilepsy, more likely to experience at least one focal to bilateral tonic-clonic seizure (69.4% vs 54.1%, p = .05). Patients with left-sided tumors were twice as likely to have experienced a focal to bilateral tonic-clonic seizure (p = .02, odds ratio [OR] = .47). Predominantly experiencing seizures with motor activity appeared to confer better overall survival, with a 65% decrease in the risk of death 10 years post diagnosis (hazard ratio [HR] = .35, p = .02). This is despite accounting for previously described prognostic markers including tumor histology/genetics, time from diagnosis to surgery, and the extent of tumor resection.

Motor seizure activity is a frequent feature in WHO grade 2 glioma and appears to confer a survival benefit regardless of histology or surgical factors. Seizures due to dominant hemisphere tumors may be more likely to propagate and cause bilateral tonic-clonic activity.