title: Seizure characteristics and control following resection in 332 patients with low-grade gliomas.
abstract: OBJECTIVE
  Seizures play an important role in the clinical presentation and postoperative quality of life of patients who undergo surgical resection of low-grade gliomas (LGGs). The aim of this study was to identify factors that influenced perioperative seizure characteristics and postoperative seizure control.
  
  
  METHODS
  The authors performed a retrospective chart review of all cases involving adult patients who underwent initial surgery for LGGs at the University of California, San Francisco between 1997 and 2003.
  
  
  RESULTS
  Three hundred and thirty-two cases were included for analysis; 269 (81%) of the 332 patients presented with >or=1 seizures (generalized alone, 33%; complex partial alone, 16%; simple partial alone, 22%; and combination, 29%). Cortical location and oligodendroglioma and oligoastrocytoma subtypes were significantly more likely to be associated with seizures compared with deeper midline locations and astrocytoma, respectively (p=0.017 and 0.001, respectively; multivariate analysis). Of the 269 patients with seizures, 132 (49%) had pharmacoresistant seizures before surgery. In these patients, seizures were more likely to be simple partial and to involve the temporal lobe, and the period from seizure onset to surgery was likely to have been longer (p=0.0005, 0.0089, and 0.006, respectively; multivariate analysis). For the cohort of patients that presented with seizures, 12-month outcome after surgery (Engel class) was as follows: seizure free (I), 67%; rare seizures (II), 17%; meaningful seizure improvement (III), 8%; and no improvement or worsening (IV), 9%. Poor seizure control was more common in patients with longer seizure history (p<0.001) and simple partial seizures (p=0.004). With respect to treatment-related variables, seizure control was far more likely to be achieved after gross-total resection than after subtotal resection/biopsy alone (odds ratio 16, 95% confidence interval 2.2-124, p=0.0064). Seizure recurrence after initial postoperative seizure control was associated with tumor progression (p=0.001).
  
  
  CONCLUSIONS
  The majority of patients with LGG present with seizures; in approximately half of these patients, the seizures are pharmacoresistant before surgery. Postoperatively, >90% of these patients are seizure free or have meaningful improvement. A shorter history of seizures and gross-total resection appear to be associated with a favorable prognosis for seizure control.
authors.affiliation: Department of Neurological Surgery and Brain Tumor Research Center, University of California, San Francisco, California 94143, USA. echang@itsa.ucsf.edu
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Potts
authors.forename: G Evren
authors.initials: GE
authors.lastname: Keles
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: Lamborn
authors.forename: Susan M
authors.initials: SM
authors.lastname: Chang
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Barbaro
authors.forename: Mitchel S
authors.initials: MS
authors.lastname: Berger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000150:complications* / Q000601:surgery; D015331:Cohort Studies; D018450:Disease Progression; D004828:Epilepsies, Partial / Q000209:etiology / Q000517:prevention & control; D017029:Epilepsy, Complex Partial / Q000209:etiology / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D005910:Glioma / Q000150:complications* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000150:complications / Q000601:surgery; D011788:Quality of Life; D012008:Recurrence; D012189:Retrospective Studies; D012640:Seizures / Q000209:etiology* / Q000517:prevention & control; D013702:Temporal Lobe / Q000473:pathology; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000927:Anticonvulsants