title: Supratentorial low-grade glioma: results and prognostic factors following postoperative radiotherapy.
abstract: OBJECTIVE
  To assess treatment outcome and prognostic factors following postoperative external radiotherapy in 77 patients with low-grade glioma.
  
  
  METHODS
  Between 1977 and 1996, 45 patients with astrocytoma, 14 with oligodendroglioma and 18 with mixed glioma received postoperative radiotherapy with a median total dose of 52 Gy (range, 45 to 61 Gy). Sixty-seven patients were treated immediately following surgery, 10 patients with tumor progression. The influence of various factors including histology, gender, age, seizures, duration of symptoms (< or = 6 weeks vs > 6 weeks), CT pattern (enhancement vs no enhancement), type of surgery, total radiotherapy dose and timing of radiotherapy on relapse-free survival and overall survival was investigated.
  
  
  RESULTS
  The median overall survival time was 81 months, the 5- and 10-year survival rates were 54% and 31%, respectively. The median time to progression was 56 months, while the 5- and 10-year progression-free survival rates were 45% and 24%. Univariate analyses identified the total radiotherapy dose (p = 0.01), duration of symptoms (p = 0.05), the presence of seizures (p = 0.04), and the CT pattern following intravenous contrast (p = 0.005) as significant prognostic factors for overall survival. Progression-free survival rates were influenced by the total dose (p = 0.04), the duration of symptoms (p = 0.01) and CT pattern (p = 0.006). On multivariate analysis, only the CT pattern (enhancement vs no enhancement) remained as independent prognostic factors for both progression-free survival and overall survival.
  
  
  CONCLUSIONS
  A minimum total dose of 52 Gy is recommended for the postoperative radiotherapy in low-grade glioma. Tumors with CT enhancement seem to need further intensification of treatment.
authors.affiliation: Department of Radiation Oncology, University Hospitals of Erlangen-Nürnberg, Germany. gerd.grabenbauer@strahlen.imed.uni-erlangen.de
authors.forename: G G
authors.initials: GG
authors.lastname: Grabenbauer
authors.forename: C M
authors.initials: CM
authors.lastname: Roedel
authors.forename: W
authors.initials: W
authors.lastname: Paulus
authors.forename: O
authors.initials: O
authors.lastname: Ganslandt
authors.forename: U
authors.initials: U
authors.lastname: Schuchardt
authors.forename: M
authors.initials: M
authors.lastname: Buchfelder
authors.forename: U
authors.initials: U
authors.lastname: Schrell
authors.forename: R
authors.initials: R
authors.lastname: Fahlbusch
authors.forename: W J
authors.initials: WJ
authors.lastname: Huk
authors.forename: R
authors.initials: R
authors.lastname: Sauer
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors