title: Prospective assessment of prostate cancer aggressiveness using 3-T diffusion-weighted magnetic resonance imaging-guided biopsies versus a systematic 10-core transrectal ultrasound prostate biopsy cohort.
abstract: BACKGROUND
  Accurate pretreatment assessment of prostate cancer (PCa) aggressiveness is important in decision making. Gleason grade is a critical predictor of the aggressiveness of PCa. Transrectal ultrasound-guided biopsies (TRUSBxs) show substantial undergrading of Gleason grades found after radical prostatectomy (RP). Diffusion-weighted magnetic resonance imaging (MRI) has been shown to be a biomarker of tumour aggressiveness.
  
  
  OBJECTIVE
  To improve pretreatment assessment of PCa aggressiveness, this study prospectively evaluated MRI-guided prostate biopsies (MR-GBs) of abnormalities determined on diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) maps. The results were compared with a 10-core TRUSBx cohort. RP findings served as the gold standard.
  
  
  METHODS
  A 10-core TRUSBx (n=64) or MR-GB (n=34) was used for PCa diagnosis before RP in 98 patients.
  
  
  METHODS
  Using multiparametric 3-T MRI: T2-weighted, dynamic contrast-enhanced imaging, and DWI were performed to identify tumour-suspicious regions in patients with a negative TRUSBx. The regions with the highest restriction on ADC maps within the suspicions regions were used to direct MR-GB. A 10-core TRUSBx was used in a matched cohort. Following RP, the highest Gleason grades (HGGs) in biopsies and RP specimens were identified. Biopsy and RP Gleason grade results were evaluated using chi-square analysis.
  
  
  CONCLUSIONS
  No significant differences on RP were observed for proportions of patients having a HGG of 3 (35% vs 28%; p=0.50), 4 (32% vs 41%; p=0.51), and 5 (32% vs 31%; p=0.61) for the MR-GB and TRUSBx cohort, respectively. MR-GB showed an exact performance with RP for overall HGG: 88% (30 of 34); for TRUS-GB it was 55% (35 of 64; p=0.001). In the MR-GB cohort, an exact performance with HGG 3 was 100% (12 of 12); for HGG 4, 91% (10 of 11); and for HGG 5, 73% (8 of 11). The corresponding performance rates for TRUSBx were 94% (17 of 18; p=0.41), 46% (12 of 26; p=0.02), and 30% (6 of 20; p=0.01), respectively.
  
  
  CONCLUSIONS
  This study shows prospectively that DWI-directed MR-GBs significantly improve pretreatment risk stratification by obtaining biopsies that are representative of true Gleason grade.
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. t.hambrock@rad.umcn.nl
authors.forename: Thomas
authors.initials: T
authors.lastname: Hambrock
authors.forename: Caroline
authors.initials: C
authors.lastname: Hoeks
authors.forename: Christina
authors.initials: C
authors.lastname: Hulsbergen-van de Kaa
authors.forename: Tom
authors.initials: T
authors.lastname: Scheenen
authors.forename: Jurgen
authors.initials: J
authors.lastname: Fütterer
authors.forename: Stefan
authors.initials: S
authors.lastname: Bouwense
authors.forename: Inge
authors.initials: I
authors.lastname: van Oort
authors.forename: Fritz
authors.initials: F
authors.lastname: Schröder
authors.forename: Henkjan
authors.initials: H
authors.lastname: Huisman
authors.forename: Jelle
authors.initials: J
authors.lastname: Barentsz
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D016009:Chi-Square Distribution; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009426:Netherlands; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000276:immunology / Q000473:pathology*; D018570:Risk Assessment; D012307:Risk Factors; D047368:Tumor Burden; D018084:Ultrasonography, Interventional
chemical_list: D017430:Prostate-Specific Antigen