title: Gleason underestimation is predicted by prostate biopsy core length.
abstract: OBJECTIVE
  To evaluate whether core length impacts biopsy accuracy and Gleason score underestimation compared to radical prostatectomy (RP) specimens.
  
  
  METHODS
  From 2010 to 2011, 8,928 cores were trans-rectal obtained from 744 consecutive patients (178 RP, 24%), 557 by an experienced performer (>250/year) and 187 (25%) by in-training urology residents. Prospectively analyzed variables were core length, age, prostate volume, free and total prostate-specific antigen (PSA), PSA density and free/total PSA ratio.
  
  
  RESULTS
  Mean core length for Gleason upgrading on RP (42.7%, n = 76) was 11.61 (±2.5, median 11.40) compared to 13.52 (±3.2, median 13.70), p < 0.001 for perfect biopsy-RP Gleason agreement (57.3%, n = 102). In multivariate analysis, for each unit of core length increment in millimeter, the Gleason upgrading risk decreased 89.9%, p = 0.049 [odds ratio (OR) 0.10, 95% confidence interval (CI) 0.01-0.99]. Biopsy positivity between experienced (35.5%) and in-training performer (30.1%) was not significantly different (p = 0.20), with comparable mean patient age (65.1 vs. 64.1), prostate volume (52.3 vs. 50.7) and median PSA (5.2 vs. 5.1), respectively. Denoting wider variability in terms of core length, in-training performers obtained significantly larger cores for positive biopsies (11.33 ± 3.42 vs. 10.83 ± 3.68), p = 0.043, compared to experienced performer (11.39 ± 3.36 vs. 11.37 ± 3.64), p = 0.30. In multivariate analysis, PSA density (OR 1.14, 95% CI 1.02-1.28) and age (OR 1.04, 95% CI 1.01-1.07) were significantly associated with biopsy positivity, p = 0.021 and p = 0.011, respectively.
  
  
  CONCLUSIONS
  While core length on trans-rectal biopsy independently affects Gleason upgrading on RP specimens, performer experience has minor impact on Gleason discordance or biopsy positivity due to a sharp learning curve.
authors.affiliation: Urology Division, Faculty of Medicine, Center for Life Sciences, Pontifical Catholic University of Campinas (PUC-Campinas), Campinas, São Paulo, Brazil, reisleo.l@gmail.com.
authors.forename: Leonardo O
authors.initials: LO
authors.lastname: Reis
authors.forename: Brunno C F
authors.initials: BC
authors.lastname: Sanches
authors.forename: Gustavo Borges
authors.initials: GB
authors.lastname: de Mendonça
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Silva
authors.forename: Tiago
authors.initials: T
authors.lastname: Aguiar
authors.forename: Ocivaldo P
authors.initials: OP
authors.lastname: Menezes
authors.forename: Athanase
authors.initials: A
authors.lastname: Billis
mesh_terms: D000368:Aged; D062005:Biopsy, Large-Core Needle / Q000379:methods / Q000592:standards*; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology*; D002983:Clinical Competence; D015331:Cohort Studies; D006801:Humans; D007396:Internship and Residency; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009929:Organ Size; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology*; D012680:Sensitivity and Specificity; D014572:Urology / Q000193:education*
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