Gleason underestimation is predicted by prostate biopsy core length.

Purpose: To evaluate whether core length impacts biopsy accuracy and Gleason score underestimation compared to radical prostatectomy (RP) specimens.

Methods: From 2010 to 2011, 8,928 cores were trans-rectal obtained from 744 consecutive patients (178 RP, 24%), 557 by an experienced performer (>250/year) and 187 (25%) by in-training urology residents. Prospectively analyzed variables were core length, age, prostate volume, free and total prostate-specific antigen (PSA), PSA density and free/total PSA ratio.