title: Nomogram to predict insignificant prostate cancer at radical prostatectomy in Korean men: a multi-center study.
abstract: OBJECTIVE
  Due to the availability of serum prostate specific antigen (PSA) testing, the detection rate of insignificant prostate cancer (IPC) is increasing. To ensure better treatment decisions, we developed a nomogram to predict the probability of IPC.
  
  
  METHODS
  The study population consisted of 1,471 patients who were treated at multiple institutions by radical prostatectomy without neoadjuvant therapy from 1995 to 2008. We obtained nonrandom samples of n = 1,031 for nomogram development, leaving n = 440 for nomogram validation. IPC was defined as pathologic organ-confined disease and a tumor volume of 0.5 cc or less without Gleason grade 4 or 5. Multivariate logistic regression model (MLRM) coefficients were used to construct a nomogram to predict IPC from five variables, including serum prostate specific antigen, clinical stage, biopsy Gleason score, positive cores ratio and maximum % of tumor in any core. The performance characteristics were internally validated from 200 bootstrap resamples to reduce overfit bias. External validation was also performed in another cohort.
  
  
  RESULTS
  Overall, 67 (6.5%) patients had a so-called "insignificant" tumor in nomogram development cohort. PSA, clinical stage, biopsy Gleason score, positive core ratio and maximum % of biopsy tumor represented significant predictors of the presence of IPC. The resulting nomogram had excellent discrimination accuracy, with a bootstrapped concordance index of 0.827.
  
  
  CONCLUSIONS
  Our current nomogram provides sufficiently accurate information in clinical practice that may be useful to patients and clinicians when various treatment options for screen-detected prostate cancer are considered.
authors.affiliation: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Chung
authors.forename: Han Yong
authors.initials: HY
authors.lastname: Choi
authors.forename: Hae-Ryoung
authors.initials: HR
authors.lastname: Song
authors.forename: Seok-Soo
authors.initials: SS
authors.lastname: Byun
authors.forename: Seong Il
authors.initials: SI
authors.lastname: Seo
authors.forename: Cheryn
authors.initials: C
authors.lastname: Song
authors.forename: Jin Seon
authors.initials: JS
authors.lastname: Cho
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Hanjong
authors.initials: H
authors.lastname: Ahn
authors.forename: Eun Sik
authors.initials: ES
authors.lastname: Lee
authors.forename: Tae-Kon
authors.initials: TK
authors.lastname: Hwang
authors.forename: Wun-Jae
authors.initials: WJ
authors.lastname: Kim
authors.forename: Moon Kee
authors.initials: MK
authors.lastname: Chung
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Jung
authors.forename: Ho Song
authors.initials: HS
authors.lastname: Yu
authors.forename: Young Deuk
authors.initials: YD
authors.lastname: Choi
mesh_terms: D000368:Aged; D044466:Asian People; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery