title: Timing of Adjuvant Radiotherapy in Glioblastoma Patients: A Single-Institution Experience With More Than 400 Patients.
abstract: BACKGROUND
  The standard of care for patients with newly diagnosed glioblastoma (GBM) is maximal safe resection followed by adjuvant radiation therapy (RT) and temozolomide (TMZ).
  
  
  OBJECTIVE
  To investigate whether the timing of adjuvant RT after surgery affected outcome in patients with GBM.
  
  
  METHODS
  We retrospectively reviewed all patients with a diagnosis of GBM at our institution. A total of 447 patients were included in our analysis. Patients were divided into 3 equal groups based on the interval between surgery and RT. The primary outcome was overall survival (OS).
  
  
  RESULTS
  Patients who began RT less than 21 days after surgery tended to be older, have a lower a Karnofsky Performance Status score, and higher recursive partitioning analysis class. These patients were more likely to have undergone biopsy only and received 3-dimensional conformal RT or 2-dimensional RT. The median OS for patients who started RT less than 21 days after surgery, between 21 and 32 days after surgery, and more than 32 days after surgery was 374, 465, and 478 days, respectively (P = .004). On multivariate Cox regression analysis, Karnofsky Performance Status score lower than 70, undergoing biopsy only, recursive partitioning analysis classes IV and V/VI, use of less than 36 Gy RT, and lack of TMZ chemotherapy were predictors of worse OS. The interval between surgery and RT was not significantly associated with OS on multivariate analysis.
  
  
  CONCLUSIONS
  Patients who begin RT less than 21 days after surgery tend to have worse prognostic factors than those who begin RT later. When accounting for significant covariates, the effect of timing between surgery and RT is not significant.
authors.affiliation: *Department of Radiation Oncology, Columbia University Medical Center, New York, New York;‡Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York;§Department of Neurological Surgery, Columbia University Medical Center, New York, New York;¶Department of Radiology, Columbia University Medical Center, New York, New York;‖The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York;#Division of Pediatric Hematology/Oncology and Stem Cell Transplantation, Department of Pediatrics, Columbia University Medical Center, New York, New York;**Department of Neurology, Columbia University Medical Center, New York, New York.
authors.forename: Tony J C
authors.initials: TJ
authors.lastname: Wang
authors.forename: Ashish
authors.initials: A
authors.lastname: Jani
authors.forename: Juan P
authors.initials: JP
authors.lastname: Estrada
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Ung
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Chow
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Soun
authors.forename: Shumaila
authors.initials: S
authors.lastname: Saad
authors.forename: Yasir H
authors.initials: YH
authors.lastname: Qureshi
authors.forename: Robyn
authors.initials: R
authors.lastname: Gartrell
authors.forename: Steven R
authors.initials: SR
authors.lastname: Isaacson
authors.forename: Simon K
authors.initials: SK
authors.lastname: Cheng
authors.forename: Guy M
authors.initials: GM
authors.lastname: McKhann
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Bruce
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Lassman
authors.forename: Michael B
authors.initials: MB
authors.lastname: Sisti
mesh_terms: D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D015415:Biomarkers; D001706:Biopsy; D001932:Brain Neoplasms / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D003131:Combined Modality Therapy; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000627:therapeutic use; D005260:Female; D005909:Glioblastoma / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D006801:Humans; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D012189:Retrospective Studies; D016019:Survival Analysis; D000077204:Temozolomide; D016896:Treatment Outcome
chemical_list: D018906:Antineoplastic Agents, Alkylating; D015415:Biomarkers; D003606:Dacarbazine; D000077204:Temozolomide