title: Initial experience with identifying high-grade prostate cancer using diffusion-weighted MR imaging (DWI) in patients with a Gleason score ≤ 3 + 3 = 6 upon schematic TRUS-guided biopsy: a radical prostatectomy correlated series.
abstract: BACKGROUND
  Diffusion-weighted magnetic resonance (MR) imaging (DWI) might be able to fulfill the need to accurately identify high-grade prostate carcinoma, in patients initially selected for active surveillance in the Prostate Specific Antigen (PSA) screening era based on transrectal ultrasound-guided biopsy Gleason score. We aimed to determine whether DWI is able to correctly identify those patients with a biopsy Gleason score of ≤ 3 + 3 = 6, but harboring Gleason 4 and/or 5 components in their radical prostatectomy (RP) specimen.
  
  
  METHODS
  Whole-mount RP specimens were used to identify regions of interest corresponding with tumor on the DWI-derived apparent diffusion coefficient (ADC) maps in 23 patients with a Gleason ≤ 3 + 3 = 6 on biopsy. ADC values were correlated with RP Gleason grades. Statistical analysis was performed by calculating area under the receiver operating characteristic curve for identification of prostate cancer with Gleason 4 and/or 5 components using DWI, and Mann-Whitney U testing was performed to detect differences in median ADC values for tumors with presence of Gleason grade 4 and/or 5 versus a highest Gleason grade of ≤ 3 on RP.
  
  
  RESULTS
  A diagnostic accuracy of median ADC values for identifying patients subject to transrectal ultrasound-guided biopsy undergrading with an area under the receiver operating characteristic curve of 0.88 was established using RP Gleason score as a reference. In patients harboring a Gleason 4 and/or 5 component, the median ADC was 0.86 × 10(-3) mm/s (standard deviation ± 0.21), whereas patients harboring no Gleason 4 and/or 5 component displayed a median ADC of 1.16 × 10(-3) mm/s (standard deviation ± 0.19) for the single tumor slice with the lowest median ADC (P < 0.002).
  
  
  CONCLUSIONS
  DWI is able to predict the presence of high-grade tumor in patients with a Gleason ≤ 3 + 3 = 6 on biopsy, providing important information for treatment decisions.
authors.affiliation: Department of Urology, Canisius-Wilhelmina Hospital Nijmegen (CWZ), Nijmegen, The Netherlands. r.somford@cwz.nl
authors.forename: Diederik M
authors.initials: DM
authors.lastname: Somford
authors.forename: Thomas
authors.initials: T
authors.lastname: Hambrock
authors.forename: Christina A
authors.initials: CA
authors.lastname: Hulsbergen-van de Kaa
authors.forename: Jurgen J
authors.initials: JJ
authors.lastname: Fütterer
authors.forename: Inge M
authors.initials: IM
authors.lastname: van Oort
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: van Basten
authors.forename: Herbert F
authors.initials: HF
authors.lastname: Karthaus
authors.forename: J Alfred
authors.initials: JA
authors.lastname: Witjes
authors.forename: Jelle O
authors.initials: JO
authors.lastname: Barentsz
mesh_terms: D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation*; D006801:Humans; D008297:Male; D060787:Neoplasm Grading / Q000295:instrumentation*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D020728:Transurethral Resection of Prostate / Q000295:instrumentation* / Q000379:methods