The Gleason score of prostate adenocarcinomas is an important preoperative 
predictor of cancer behavior, and is used to help guide treatment. In the 
setting of more than two positive biopsy sites, pathologists usually grade the 
tumor at each site separately, and the Gleason score may differ from each 
positive site. This study seeks to determine if the highest Gleason score in all 
biopsy sites, or the Gleason score in the site with the highest tumor volume on 
the needle biopsy is the best predictor of final Gleason score in the radical 
prostatectomy specimens. Various preoperative biopsy findings were analyzed. All 
151 patients had at least two positive biopsy sites and underwent radical 
prostatectomy. Primary and secondary Gleason pattern grades were assigned for 
each positive biopsy site. The tumor volume in the needle biopsy site was 
defined by the percentage of areas of biopsy cores involved by cancer. The 
radical prostatectomy specimens were completely embedded and processed in the 
whole-mount method. The Gleason score from both the biopsy site with the highest 
Gleason score and the biopsy site with the highest tumor volume on the needle 
biopsy correlated equally well with final Gleason score at radical prostatectomy 
(Spearman correlation coefficient =0.54 for both, P<0.001). The Gleason score 
from both the biopsy site with the highest Gleason score and the biopsy site 
with the highest tumor volume on the needle biopsy also correlated with primary 
Gleason pattern grade at radical prostatectomy (Spearman correlation coefficient 
=0.53 for both, P<0.001). Secondary Gleason pattern grade from the biopsy site 
with the highest tumor volume on the needle biopsy correlated with secondary 
Gleason pattern grade at radical prostatectomy slightly better than those from 
the biopsy site with the highest Gleason score (Spearman correlation 
coefficient, 0.32 vs 0.24; both P<0.001). Our data indicate that the highest 
Gleason score from all sites and the Gleason score from the site with the 
highest tumor volume on the needle biopsy are equally and significantly 
predictive of final Gleason score on radical prostatectomy. Both methods of 
prediction are significantly predictive of primary and secondary Gleason pattern 
grade on radical prostatectomy. We recommend that the highest Gleason score from 
all positive biopsy sites should be used when assigning an initial score using 
needle biopsies.