title: Effect of the number of core biopsies of the prostate on predicting Gleason score of prostate cancer.
abstract: OBJECTIVE
  We determined the effect of the number of core biopsies of the prostate on predicting the Gleason score of the prostatectomy specimen.
  
  
  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.
authors.affiliation: Swedish Medical Center, Englewood.
authors.forename: D
authors.initials: D
authors.lastname: Thickman
authors.forename: W C
authors.initials: WC
authors.lastname: Speers
authors.forename: P J
authors.initials: PJ
authors.lastname: Philpott
authors.forename: H
authors.initials: H
authors.lastname: Shapiro
mesh_terms: D000704:Analysis of Variance; D001707:Biopsy, Needle / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D009367:Neoplasm Staging; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results