title: Factors associated with seizure freedom in the surgical resection of glioneuronal tumors.
abstract: OBJECTIVE
  Gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNETs) are low-grade brain tumors of glioneuronal origin that commonly present with seizures. Achieving seizure control in patients with glioneuronal tumors remains underappreciated, as tumor-related epilepsy significantly affects patients' quality-of-life.
  
  
  METHODS
  We performed a quantitative and comprehensive systematic literature review of seizure outcomes after surgical resection of GGs and DNETs associated with seizures. We evaluated 910 patients from 39 studies, and stratified outcomes according to several potential prognostic variables.
  
  
  RESULTS
  Overall, 80% of patients were seizure-free after surgery (Engel class I), whereas 20% continued to have seizures (Engel class II-IV). We observed significantly higher rates of seizure-freedom in patients with ≤1 year duration of epilepsy compared to those with >1 year of seizures [odds ratio (OR) 9.48; 95% confidence interval (CI) 2.26-39.66], and with gross-total resection over subtotal lesionectomy (OR 5.34; 95% CI 3.61-7.89). In addition, the presence of secondarily generalized seizures preoperatively predicted a lower rate of seizure-freedom after surgery (OR 0.40; 95% CI 0.24-0.66). Outcomes did not differ significantly between adults and children, patients with temporal lobe versus extratemporal tumors, pathologic diagnosis of GG versus DNET, medically controlled versus refractory seizures, or with the use of electrocorticography (ECoG). Extended resection of temporal lobe tumors, with hippocampectomy and/or corticectomy, conferred additional benefit.
  
  
  CONCLUSIONS
  These results suggest that early operative intervention and gross-total resection are critically important factors in achieving seizure-freedom, and thus improving quality-of-life, in patients with glioneuronal tumors causing epilepsy.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, California 94143-0112, USA.
authors.forename: Dario J
authors.initials: DJ
authors.lastname: Englot
authors.forename: Mitchel S
authors.initials: MS
authors.lastname: Berger
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Barbaro
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
mesh_terms: D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery*; D004569:Electroencephalography; D018303:Ganglioglioma / Q000150:complications / Q000473:pathology / Q000601:surgery*; D006801:Humans; D018302:Neoplasms, Neuroepithelial / Q000150:complications / Q000473:pathology / Q000601:surgery*; D012640:Seizures / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D016896:Treatment Outcome