title: External validation of a nomogram predicting the probability of prostate cancer Gleason sum upgrading between biopsy and radical prostatectomy pathology among Japanese patients.
abstract: OBJECTIVE
  To explore the rate of upgrading in a contemporary cohort from 2 Japanese institutions, and evaluating the predictive accuracy of the nomogram when applied to patients, regardless of race. Previous reports have indicated that a maximum of 43% of men with prostate cancer will show an upgraded Gleason score from biopsy to radical prostatectomy (RP). A preparative nomogram was developed at the University of Hamburg to predict the probability of upgrading from biopsy to RP specimen.
  
  
  METHODS
  Clinical and pathologic data of 503 patients from 2 Japanese institutions were supplied for validation. Nomogram-predicted probabilities of upgrading from biopsy to RP specimen were compared with actual rate of upgrading. The area under the receiver operating characteristic curve (AUC) was calculated for all patients. Calibration of the nomogram was achieved by comparing the predicted upgrading rate with that of an ideal nomogram.
  
  
  RESULTS
  Gleason sum upgrading was recorded in 29.8% of patients at RP. Accuracy of the nomogram was 79.2% (confidence interval, 75.1%-83.2%). Overall AUC was 0.79 when applied to the validation dataset, with individual institutional AUCs ranging from 0.79-0.80. Nomogram predictions of upgrading were not within 10% of an ideal nomogram.
  
  
  CONCLUSIONS
  Gleason sum upgrading between biopsy and final pathology represents an important consideration in treatment decision-making, and nearly one third of patients with prostate cancer will be upgraded. The Hamburg nomogram seems to provide reasonably accurate predictions regardless of minor variations in pathologic assessment, but is not necessarily so accurate when applied to Japanese patient population.
authors.affiliation: Department of Urology, Graduate School of Medicine, Chiba University, Chiba, Japan. t-imamo@pg7.so-net.ne.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Imamoto
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takanobu
authors.initials: T
authors.lastname: Utsumi
authors.forename: Makoto
authors.initials: M
authors.lastname: Takano
authors.forename: Takahito
authors.initials: T
authors.lastname: Suyama
authors.forename: Koji
authors.initials: K
authors.lastname: Kawamura
authors.forename: Naoto
authors.initials: N
authors.lastname: Kamiya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Naya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ueda
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ichikawa
mesh_terms: D000368:Aged; D001706:Biopsy; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery