title: Changes in serial magnetic resonance spectroscopy predict outcome in high-grade glioma during and after postoperative radiotherapy.
abstract: OBJECTIVE
  To determine any correlation between magnetic resonance spectroscopy (MRS) pattern of high-grade glioma before, during, and after radiotherapy (RT) with overall survival (OS) and progression-free survival (PFS).
  
  
  METHODS
  Twenty-six patients prospectively underwent surgery and RT to 60 Gy. MRS was performed before RT, at week 4 of RT, and 2 months post-RT. Normalized and relative metabolite ratios were evaluated. Patients were grouped according to similar evolving MRS patterns and analyzed for differences in OS and PFS.
  
  
  RESULTS
  Significant decreases in tumor choline/N-acetyl-aspartate and normalized choline were observed from baseline to post-RT. After a median follow-up of 22.9 months, patients with >40% decrease in normalized choline from week 4 during RT to 2 months post-RT had a significantly worse median OS (9.1 months vs. not reached, p<0.00001) and PFS (5.8 vs. 19.8 months, p=0.0018).
  
  
  CONCLUSIONS
  The change in normalized choline at 2 months post-RT was highly prognostic for PFS and OS. This may allow more individualized response-based treatment.
authors.affiliation: Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, AB, Canada.
authors.forename: Harvey
authors.initials: H
authors.lastname: Quon
authors.forename: Bryan
authors.initials: B
authors.lastname: Brunet
authors.forename: Abraham
authors.initials: A
authors.lastname: Alexander
authors.forename: Albert
authors.initials: A
authors.lastname: Murtha
authors.forename: Bassam
authors.initials: B
authors.lastname: Abdulkarim
authors.forename: Dorcas
authors.initials: D
authors.lastname: Fulton
authors.forename: Marie
authors.initials: M
authors.lastname: Smerdely
authors.forename: Maryann
authors.initials: M
authors.lastname: Johnson
authors.forename: Raul
authors.initials: R
authors.lastname: Urtasun
authors.forename: Samir
authors.initials: S
authors.lastname: Patel
authors.forename: Sunita
authors.initials: S
authors.lastname: Ghosh
authors.forename: Wilson
authors.initials: W
authors.lastname: Roa
mesh_terms: D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D006801:Humans; D053208:Kaplan-Meier Estimate; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D013997:Time Factors; D016896:Treatment Outcome