title: Diffusion tensor invasive phenotypes can predict progression-free survival in glioblastomas.
abstract: BACKGROUND
  Glioblastomas multiformes (GBM) remain incurable in most cases. Their invasion into normal brain makes current therapies ineffective. Post-mortem studies suggest about a 25% of GBMs invade less than 1 cm from the tumour bulk and 20% invade more than 3 cm.
  
  
  OBJECTIVE
  The study aims to use DTI to assess tumour extension and determine how previously reported patterns relate to the progression-free survival (PFS).
  
  
  METHODS
  Twenty-five patients with GBM treated according to the EORTC/NCIC protocol were retrospectively analysed. Patients were imaged post-operatively at 1.5 T. The sequences were composed of standard anatomical and a standard DTI sequence. As described earlier p and q maps were constructed. For each of the p and q maps, regions of interest were drawn around the visible abnormality. Patients were assigned a diffuse, localised or minimally invasive pattern. Progression was defined according to the RANO criteria (4) and PFS determined in days. Kaplan-Meier plots of survival for the three groups were plotted as were the proportion of patients who had not progressed at 24 months.
  
  
  RESULTS
  The median PFS for the diffuse group was 278 days, for the localised group 605 days and 820 days for the minimally invasive group. Three-fourth of the minimally invasive group were progression-free at 24 months (LOG RANK 9.25; p = 0.010).
  
  
  CONCLUSIONS
  It is possible to identify three invasive phenotypes in GBMs using Diffusion tensor imaging , and these three phenotypes have different progression free survival. A minimal phenotype (20% of patients) predicts a greater delay to progression.
authors: Department of Radiology, University of Cambridge , Cambridge , UK.
authors: L A
authors: LA
authors: Mohsen
authors: V
authors: V
authors: Shi
authors: R
authors: R
authors: Jena
authors: J H
authors: JH
authors: Gillard
authors: S J
authors: SJ
authors: Price
mesh_terms: D000328:Adult; D000368:Aged; D024221:Antineoplastic Protocols; D001932:Brain Neoplasms / Q000145:classification / Q000473:pathology* / Q000628:therapy; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000145:classification / Q000473:pathology* / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome