title: Prostatic ductal adenocarcinoma: An aggressive variant that is underdiagnosed and undersampled on transrectal ultrasound (TRUS)-guided needle biopsy.
abstract: BACKGROUND
  We sought to determine if prostatic ductal adenocarcinoma is undersampled and/or underdiagnosed at transrectal ultrasound (TRUS)-guided biopsy.
  
  
  METHODS
  With institutional review board approval, we searched our pathology database between 2008 and 2014 for patients with a diagnosis of ≥10% ductal adenocarcinoma on radical prostatectomy and available TRUS-guided needle biopsy specimens. Three blinded genitourinary pathologists independently examined the biopsy slides. The presence or absence of ductal adenocarcinoma was determined. Diagnostic accuracy was calculated using consensus diagnosis as the reference standard. Inter-observer agreement was assessed using Cohen's kappa coefficient.
  
  
  RESULTS
  Based on consensus review, 66.7% (12/18) biopsy specimens demonstrated ductal adenocarcinoma and 33.3% (6/18) demonstrated conventional acinar prostatic adenocarcinoma. The sensitivity/specificity for each reader (R) was: 83/100% (R1), 100/83% (R2) and 58/83% (R3) and the inter-observer agreement was only fair (K=0.32). Only two of the original needle-biopsy reports correctly identified ductal adenocarcinoma (sensitivity = 17%). The main limitations of the study are the relatively small sample size and the potential for selection bias since we could only examine patients who underwent radical prostatectomy.
  
  
  CONCLUSIONS
  Prostatic ductal adenocarcinoma may be undersampled at TRUS-guided biopsy and in this study was under-reported in routine clinical practice. This highlights the importance of increased awareness of ductal adeoncarcinoma and the need for clear diagnostic criteria. These findings have significant clinical impact especially when determining candidacy for active surveillance protocols.
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Previn
authors.initials: P
authors.lastname: Gulavita
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Shaheed W
authors.initials: SW
authors.lastname: Hakim
authors.affiliation: Department of Medical Imaging, The Ottawa Hospital, Ottawa, ON;
authors.forename: Nicola
authors.initials: N
authors.lastname: Schieda
authors.affiliation: Department of Urology, The Ottawa Hospital, Ottawa, ON.
authors.forename: Rodney H
authors.initials: RH
authors.lastname: Breau
authors.affiliation: Department of Urology, The Ottawa Hospital, Ottawa, ON.
authors.forename: Chris
authors.initials: C
authors.lastname: Morash
authors.affiliation: Department of Urology, The Ottawa Hospital, Ottawa, ON.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Keefe
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Robertson
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Kien T
authors.initials: KT
authors.lastname: Mai
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Eric C
authors.initials: EC
authors.lastname: Belanger
authors.affiliation: Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON;
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Flood