title: Pretreatment evaluation of microcirculation by dynamic contrast-enhanced magnetic resonance imaging predicts survival in primary rectal cancer patients.
abstract: OBJECTIVE
  To investigate the prognostic value of the perfusion index (PI), a microcirculatory parameter estimated from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), which integrates information on both flow and permeability, to predict overall survival and disease-free survival in patients with primary rectal cancer.
  
  
  METHODS
  A total of 83 patients with stage cT3 rectal cancer requiring neoadjuvant chemoradiation were investigated with DCE-MRI before start of therapy. Contrast-enhanced dynamic T1 mapping was obtained, and a simple data analysis strategy based on the calculation of the maximum slope of the tissue concentration-time curve divided by the maximum of the arterial input function was used as a measure of tumor microcirculation (PI), which integrates information on both flow and permeability.
  
  
  RESULTS
  In 39 patients (47.0%), T downstaging (ypT0-2) was observed. During a mean (±SD) follow-up period of 71 ± 29 months, 58 patients (69.9%) survived, and disease-free survival was achieved in 45 patients (54.2%). The mean PI (PImean) averaged over the group of nonresponders was significantly higher than for responders. Additionally, higher PImean in age- and gender-adjusted analyses was strongly predictive of therapy nonresponse. Most importantly, PImean strongly and significantly predicted disease-free survival (unadjusted hazard ratio [HR], 1.85 [ 95% confidence interval, 1.35-2.54; P<.001)]; HR adjusted for age and sex, 1.81 [1.30-2.51]; P<.001) as well as overall survival (unadjusted HR 1.42 [1.02-1.99], P=.040; HR adjusted for age and sex, 1.43 [1.03-1.98]; P=.034).
  
  
  CONCLUSIONS
  This analysis identifies PImean as a novel biomarker that is predictive for therapy response, disease-free survival, and overall survival in patients with primary locally advanced rectal cancer.
authors.affiliation: Department of Radio-Oncology, Academic Teaching Hospital Feldkirch, Feldkirch, Austria.
authors.forename: Alexander Friedrich
authors.initials: AF
authors.lastname: DeVries
authors.affiliation: Department of Oncology, Wels-Grieskirchen Medical Hospital, Wels, Austria. Electronic address: gudrun.piringer@hotmail.com.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Piringer
authors.affiliation: Department of Radiology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Kremser
authors.affiliation: Department of Radiology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Judmaier
authors.affiliation: Department of Medicine and Cardiology, Academic Teaching Hospital Feldkirch, Feldkirch, Austria.
authors.forename: Christoph Hubert
authors.initials: CH
authors.lastname: Saely
authors.affiliation: Department of Radio-Oncology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Lukas
authors.affiliation: Department of Surgery, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Öfner
mesh_terms: D000367:Age Factors; D000368:Aged; D002199:Capillary Permeability; D059186:Chemoradiotherapy, Adjuvant; D003287:Contrast Media; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D012004:Rectal Neoplasms / Q000098:blood supply* / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D012737:Sex Factors
chemical_list: D003287:Contrast Media