title: Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors.
abstract: OBJECTIVE
  To compare histological outcomes in patients undergoing MRI-transrectal ultrasound fusion transperineal (MTTP) prostate biopsy and determine the incremental benefit of targeted cores.
  
  
  METHODS
  Seventy-six consecutive patients with 89 MRI-identified targets underwent MTTP biopsy. Separate targeted biopsies and background cores were obtained according to a standardized protocol. Target biopsies were considered of added diagnostic value if these cores showed a higher Gleason grade than non-targeted cores taken from the same sector (Group 1, n = 41). Conversely, where background cores demonstrated an equal or higher Gleason grade, target cores were considered to be non-beneficial (Group 2, n = 48).
  
  
  RESULTS
  There was no significant difference in age, PSA, prostate volume, time-to-biopsy, and number of cores obtained between the groups. A greater proportion of target cores were positive for cancer (158/228; 69.3 %) compared to background (344/1881; 18.38 %). The median target volume was 0.54 cm(3) for Group 1 (range 0.09-2.79 cm(3)) and 1.65 cm(3) for Group 2 (0.3-9.07 cm(3)), p < 0.001. The targets in Group 1 had statistically lower diameters for short and long axes, even after correction for gland size. The highest area under the receiver operating characteristic curve was demonstrated when a lesion cutoff value of 1.0 cm in short axis was applied, resulting in a sensitivity of 83.3 % and a specificity of 82.9 %.
  
  
  CONCLUSIONS
  When a combined systematic and targeted transperineal prostate biopsy is performed, there is limited benefit in acquiring additional cores from larger-volume targets with a short axis diameter >1.0 cm.
authors.affiliation: Department of Radiology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK. tristan.barrett@addenbrookes.nhs.uk.|University of Cambridge, Cambridge, CB2 0QQ, UK. tristan.barrett@addenbrookes.nhs.uk.
authors.forename: Tristan
authors.initials: T
authors.lastname: Barrett
authors.affiliation: Department of Radiology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Patterson
authors.affiliation: Department of Radiology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Brendan C
authors.initials: BC
authors.lastname: Koo
authors.affiliation: Department of Urology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Karan
authors.initials: K
authors.lastname: Wadhwa
authors.affiliation: Department of Histopathology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Anne Y
authors.initials: AY
authors.lastname: Warren
authors.affiliation: Department of Urology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Doble
authors.affiliation: University of Cambridge, Cambridge, CB2 0QQ, UK.|Department of Urology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.|Translational Prostate Cancer Group, Department of Oncology, Hutchinson-MRC Research Centre, University of Cambridge, Cambridge, UK.
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Gnanapragasam
authors.affiliation: Department of Urology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
authors.forename: Christof
authors.initials: C
authors.lastname: Kastner
authors.affiliation: Department of Radiology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.|University of Cambridge, Cambridge, CB2 0QQ, UK.
authors.forename: Ferdia A
authors.initials: FA
authors.lastname: Gallagher
mesh_terms: D000368:Aged; D005500:Follow-Up Studies; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading / Q000379:methods*; D010502:Perineum; D011467:Prostate / Q000000981:diagnostic imaging*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: Image-guided biopsy; Magnetic resonance imaging; Prostate cancer; Transperineal; Ultrasound