title: Gleason Misclassification Rate Is Independent of Number of Biopsy Cores in Systematic Biopsy.
abstract: To compare the utility of saturation core biopsy and 12-core biopsy in detecting true Gleason grades, using final pathology in prostatectomy specimens as outcome measures, with a particular interest in Gleason upgrading.
  
  
  
  We compared the concordance rates of Gleason grades diagnosed on biopsies and prostatectomy specimens in 375 consecutive patients, including 106 saturation biopsies (18-33 cores, median = 20 cores) and 269 12-core biopsies. Grading bias was addressed by a central rereview of all cases that had discordance in reporting high Gleason grades (Gleason grade ≥ 4) on biopsies and prostatectomy specimens.
  
  
  
  For patients with high Gleason grades on final pathology, saturation and 12-core biopsy schemes had a comparable sensitivity, specificity, negative and positive predictive values (72.5% vs 69.5%, 91.9% vs 97.6%, 64.2% vs 58.4%, and 94.3% vs 98.5%, respectively) in detecting high Gleason grades. On multivariate analysis, prebiopsy serum prostate-specific antigen and clinical T stage independently predicted Gleason upgrading; saturation biopsy was not a significant predictor. Approximately one-third of cases where high Gleason grade was not present in the biopsy were attributed to the confinement of high-grade tumors to unusual anatomic locations such as anterior lobes, apex, bladder neck, and parasagittal zones.
  
  
  
  Our study showed that Gleason misclassification rate is independent of the number of biopsy cores in systematic biopsy. One of the reasons for missing high Gleason grade tumors on systematic biopsy was unusual tumor location outside of the biopsy grid, supporting the need for improved detection technique such as magnetic resonance imaging-guided targeted biopsies.
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Liza
authors.initials: L
authors.lastname: Quintana
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Ward
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Gerrin
authors.affiliation: Department of Pathology, Tufts Medical Center, Boston, MA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Genega
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Seymour
authors.initials: S
authors.lastname: Rosen
authors.affiliation: Department of Urology, Emory University School of Medicine, Atlanta, GA.
authors.forename: Martin G
authors.initials: MG
authors.lastname: Sanda
authors.affiliation: Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Wagner
authors.affiliation: Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Peter
authors.initials: P
authors.lastname: Chang
authors.affiliation: Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: William C
authors.initials: WC
authors.lastname: DeWolf
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA. Electronic address: hye@bidmc.harvard.edu.
authors.forename: Huihui
authors.initials: H
authors.lastname: Ye
mesh_terms: D000368:Aged; D062005:Biopsy, Large-Core Needle / Q000706:statistics & numerical data; D003951:Diagnostic Errors; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies