title: The diagnostic ability of an additional midline peripheral zone biopsy in transrectal ultrasonography-guided 12-core prostate biopsy to detect midline prostate cancer.
abstract: OBJECTIVE
  The goal of this study was to evaluate the diagnostic effect of adding a midline peripheral zone (PZ) biopsy to the 12-core biopsy protocol used to diagnose prostate cancer (PC), and to assess the clinical and pathologic characteristics of midline-positive PC in order to identify a potential subgroup of patients who would require midline PZ biopsy.
  
  
  METHODS
  This study included 741 consecutive patients who underwent a transrectal ultrasonography-guided, 12-core prostate biopsy with an additional midline core biopsy between October 2012 and December 2013. We grouped patients by the presence or absence of PC and subdivided patients with PC based on the involvement of the midline core. The clinical characteristics of these groups were compared, including serum prostate-specific antigen (PSA) concentrations, PSA density, and pathological features in the biopsy specimens.
  
  
  RESULTS
  PC was detected in 289 patients (39.0%). Among the PC patients, 66 patients (22.8%) had midline PC. No patients were diagnosed with PC based only on a midline core. The Gleason scores, number of positive cores, tumor core length, serum PSA concentrations, and PSA density were significantly higher in patients with midline-positive PC (P<0.001). Furthermore, significant cancer was more frequent in the midline-positive group (98.5% vs. 78.0%).
  
  
  CONCLUSIONS
  Patients showing a positive result for PC in a midline PZ biopsy were more likely to have multiple tumors or large-volume PC with a high tumor burden. However, our data indicated that an additional midline core biopsy is unlikely to be helpful in detecting occult midline PC.
authors.affiliation: Department of Radiology, Seoul National University Hospital and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Inpyeong
authors.identifier: 0000-0002-1291-8973
authors.initials: I
authors.lastname: Hwang
authors.affiliation: Department of Radiology, Seoul National University Hospital and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Sang Youn
authors.identifier: 0000-0003-4038-7345
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University Hospital and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Jeong Yeon
authors.identifier: 0000-0001-8659-0918
authors.initials: JY
authors.lastname: Cho
authors.affiliation: Department of Radiology, Seoul National University Hospital and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Myoung Seok
authors.identifier: 0000-0001-5285-4874
authors.initials: MS
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul National University Hospital and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Seung Hyup
authors.identifier: 0000-0002-9339-5907
authors.initials: SH
authors.lastname: Kim
keywords: Image-guided biopsy; Prostatic neoplasms; Ultrasonography