title: The role of 3-tesla diffusion-weighted magnetic resonance imaging in selecting prostate cancer patients for active surveillance.
abstract: OBJECTIVE
  Differentiating significant cancer from insignificant cancer is a major challenge in active surveillance (AS) for prostate cancer. We evaluated whether the apparent diffusion coefficient (ADC) grade from 3-T diffusion-weighted magnetic resonance imaging (DW-MRI) is useful to exclude men with unfavorable pathological features from men meeting current AS eligibility criteria.
  
  
  METHODS
  Among patients who underwent radical prostatectomy, 117 potential AS candidates defined according to 2013 European Association of Urology guidelines who had undergone preoperative 3-T DW-MRI were included. A blinded uro-radiologist graded the level of suspicion from the ADC map using the Likert scale from 1 to 5. The rate of unfavorable pathological features was evaluated according to ADC grade. Unfavorable pathological features were defined as non-organ-confined disease or pathological Gleason score≥7 (4+3). The associations between unfavorable pathological features and clinical variables including ADC grade (>3 vs. ≤3) were evaluated using logistic regression analysis.
  
  
  RESULTS
  The rates of unfavorable pathological features were 0.0% (0/14), 2.9% (1/34), 5.4% (2/37), 25.0% (6/24), and 37.5% (3/8) from grades 1 to 5 (P=0.002). The predictive accuracy was as high as 0.804. The rates were significantly different between low (≤3, 3.5%) and high (>3, 28.1%, P<0.001) grades. The sensitivity, specificity, and positive and negative predictive values were 75.0%, 78.1%, 28.1%, and 96.5%. ADC grade (odds ratio [OR], 10.696; 95% confidence interval [CI], 2.675-42.773) was significantly associated with unfavorable pathological features, even after adjusting for other variables (OR, 11.274; 95% CI, 2.622-48.471).
  
  
  CONCLUSIONS
  ADC grade from 3-T DW-MRI is useful to predict men with unfavorable pathologic features from AS candidates.
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Chang Wook
authors.initials: CW
authors.lastname: Jeong
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Park
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sung Ii
authors.initials: SI
authors.lastname: Hwang
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sangchul
authors.initials: S
authors.lastname: Lee
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Seong Jin
authors.initials: SJ
authors.lastname: Jeong
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sung Kyu
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Seok-Soo
authors.initials: SS
authors.lastname: Byun
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Hak Jong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Departments of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
keywords: Magnetic resonance imaging; Pathology; Prostatic neoplasms; Watchful waiting