does prostate biopsy gleason score accurately express the biologic features of prostate cancer purpose to correlate gleason grading in prostate biopsies with the final gleason score in radical prostatectomy specimens and to investigate predictors for concordance and preoperative undergradingmaterials and methods the charts of 303 patients who underwent radical retropubic prostatectomy between 1992 and 2002 were retrospectively reviewed prostate biopsy and surgical specimen gleason scores and correlative clinical data were recorded and a multivariate analysis model was appliedresults data were available in 293 cases 97 the preoperative biopsy predicted the prostatectomy gleason score accurately in 51 and undergraded them in 41 of the patients accuracy rates were significantly higher for gleason scores 710 compared to low gleason scores 24 concordance 90 and 6 respectively p 001 moreover accuracy rates were higher in patients with prostatespecific antigen psa higher than 10 ngml 85 vs 40 p 001 and prostate glands smaller than 55 g 68 vs 38 p 001 in 233 patients the biopsy gleason score did not include 4 or 5 components upgrading to 4 or 5 in 1 of the components was noted in 32 patients 14 multivariate analysis revealed that upgrading is associated with preoperative serum psa odds ratio 105 p 005 and the percentage of positive cores in the biopsy odds ratio 147 p 0001conclusions biopsy gleason scores of 24 low psa and a low percentage of positive cores in the biopsy can predict the biopsy driven biologically significant undergrading of 1 of the components of the gleason score that may adversely affect therapeutic decisions