Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors.

To compare histological outcomes in patients undergoing MRI-transrectal ultrasound fusion transperineal (MTTP) prostate biopsy and determine the incremental benefit of targeted cores.

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)

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 %

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

World journal of urology 2015 Aug 04 [Epub ahead of print]

Tristan Barrett, Andrew J Patterson, Brendan C Koo, Karan Wadhwa, Anne Y Warren, Andrew Doble, Vincent J Gnanapragasam, Christof Kastner, Ferdia A Gallagher

Department of Radiology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK, tristan