title: Can diffusion-weighted magnetic resonance imaging predict a high Gleason score of prostate cancer?
abstract: OBJECTIVE
  To determine the relationship between cancer-positive findings on diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) and the Gleason score (GS) of radical prostatectomy specimens in prostate cancer (PC).
  
  
  METHODS
  We performed a retrospective study of 105 consecutive patients with PC who underwent radical prostatectomy between January 2009 and October 2011 with DWI MRI and full data available for analyses. Prostatectomy specimen pathology included GS, margin status, and capsule invasion, and the clinical factors investigated included age and serum prostate-specific antigen. We investigated the relationship between positive DWI MRI results and these pathological and clinical factors.
  
  
  RESULTS
  PC was diagnosed in 62 of 105 patients on DWI MRI. The prostatectomy specimens revealed that the number of cases with GS >4+3 was significantly greater in patients with PC-positive DWI MRI results (34/62, 54.80%) than in those with PC-negative results (2/43, 2.33%; p<0.0001). Positive surgical margins occurred significantly more often in cases with PC-positive DWI MRI results (31/62, 50.0%, compared with 9/43, 21.4%; p=0.0253), and patients with a single tumor lesion in DWI MRI had significantly higher GSs than did those with multiple tumor lesions (p=0.0301). Our statistical results with multiple regression analysis showed that PC-positive DWI MRI results are significantly associated with high GSs.
  
  
  CONCLUSIONS
  DWI MRI may help to predict high GSs in prostatectomy specimens. Further studies assessing a greater number of patients will be necessary for a definitive evaluation of DWI MRI as a diagnostic tool for determining PC malignancy.
authors.affiliation: Department of Urology, Shinko Hospital, Kobe, Japan. ; Department of Urology, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shigemura
authors.forename: Nozomu
authors.initials: N
authors.lastname: Yamanaka
authors.forename: Masuo
authors.initials: M
authors.lastname: Yamashita
keywords: Diffusion magnetic resonance imaging; Neoplasm grading; Prostatic neoplasms