Effect of the Number of Core Biopsies of the Prostate on Predicting Gleason Score of Prostate Cancer

PURPOSE: We determined the effect of the number of core biopsies of the prostate on predicting the Gleason score of the prostatectomy specimen. MATERIALS AND METHODS: The Gleason scores from 124 radical prostatectomy specimens were compared to those from preoperative core needle biopsies of the prostate. The number of cores obtained and tumor stage were compared regarding agreement in prostate cancer score. RESULTS: Four to 6 core biopsies yielded the best results, with agreement within 1 Gleason score in 75% of the cases. Further increases in the number of core biopsies did not improve results. Additionally, 37% of the well differentiated tumors on core biopsy were stage C. CONCLUSIONS: Gleason score from the core biopsy has limitations in respect to predicting prostatectomy tumor score and stage and, therefore, it is problematic for use in therapeutic decision making.