title: The impact of extent of resection and histological subtype on the outcome of adult patients with high-grade gliomas.
abstract: OBJECTIVE
  We reviewed the relationship between extent of resection and survival of patients with high-grade gliomas with special consideration of an oligodendroglial component.
  
  
  METHODS
  A retrospective review was performed on 160 adult patients with histological diagnosis of high-grade gliomas since 2000. All histological slides were categorized as high-grade astrocytomas or oligodendroglial tumors. Extent of resection was assessed by early post-operative magnetic resonance imaging and classified as complete resection, incomplete resection and biopsy. Measured outcomes were overall survival and progression-free survival. The independent association of extent of resection and survival was analyzed by the multivariate proportional hazard model adjusting for prognostic factors.
  
  
  RESULTS
  The lesions were classified as high-grade astrocytomas in 93 patients and high-grade oligodendroglial tumors in 67 patients. In high-grade astrocytomas, the median survival after complete resection (n = 36), incomplete resection (n = 36) and biopsy (n = 21) was 23.4, 15.3 and 12.6 months, respectively. Complete resection was independently associated with increased overall survival (P < 0.001) and progression-free survival (P = 0.002) compared with incomplete resection, while incomplete resection was not associated with survival benefit compared with biopsy by multivariate analysis. On the other hand, in high-grade oligodendroglial tumors, the majority of patients were still alive and there is no significant difference in the survival between complete resection (n = 24) and incomplete resection (n = 33), while even incomplete resection had a significantly longer overall survival (P < 0.001) and progression-free survival (P = 0.006) compared with biopsy (n = 10).
  
  
  CONCLUSIONS
  Maximal cytoreduction improves the survival of high-grade gliomas, although our data indicated that the impact of extent of resection in high-grade astrocytomas is different from that in high-grade oligodendroglial tumors.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, North-15, West-7, Kita-ku, Sapporo 060-8638, Japan. terasas@med.hokudai.ac.jp
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Terasaka
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Ishii
authors.forename: Jun
authors.initials: J
authors.lastname: Ikeda
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kanno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishihara
authors.forename: Shinya
authors.initials: S
authors.lastname: Tanaka
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Houkin
mesh_terms: D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000401:mortality / Q000601:surgery; D001932:Brain Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D009837:Oligodendroglioma / Q000401:mortality / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome