title: Assessing the clinical benefit of a nomogram to predict specimen-confined disease at radical prostatectomy in patients with high-risk prostate cancer: An external validation.
abstract: OBJECTIVE
  The objective of the current study was to test generalizability and clinical value of a recently published nomogram to predict specimen-confined disease (SCD, pT2-pT3a+R0+pN0) at radical prostatectomy (RP) in patients with clinical high-risk prostate cancer (HRPCa). The nomogram allows improved decision making with curative intent within this heterogeneous patient cohort, which is important, as RP in patients with clinical HRPCa remains a topic of controversy.
  
  
  METHODS
  We externally validated the nomogram in 1,669 men with clinical HRPCa who underwent RP and extended pelvic lymph node dissection between 1992 and 2011. A Kaplan-Meier analysis to estimate 5- and 10-year biochemical recurrence-free survival was performed. To investigate the SCD model׳s performance, the previously reported regression coefficients of the SCD nomogram were applied. Within loess calibration plots, the extent of overestimation or underestimation was graphically explored. Finally, decision curve analysis (DCA) to assess the clinical value of the SCD nomogram was performed.
  
  
  RESULTS
  Overall, 49% of men showed SCD after RP. The 5- and 10-year biochemical recurrence rates for men with SCD were 66% and 56%, respectively, vs. 32% and 20%, respectively, for men without SCD (log-rank test P<0.001). External validation demonstrated comparable accuracy in relation to accuracy derived from internal validation (68.1% vs. 72.0%). Calibration was suboptimal, showing a tendency to underestimate SCD probability. In DCA, the nomogram׳s usage was associated with a clinical net benefit relative to both treating all and none.
  
  
  CONCLUSIONS
  Within our cohort, the nomogram׳s use was associated with a clinical net benefit according to DCA. However, one-third of men were falsely classified as having SCD or non-SCD. Nevertheless, in the absence of superior tools, the SCD nomogram represents a useful clinical decision aid.
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Department of Urology, Vivantes Auguste-Viktoria-Klinikum, Berlin, Germany. Electronic address: jenshansen81@gmail.com.
authors.forename: Jens
authors.initials: J
authors.lastname: Hansen
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Martini Clinic, Prostate Cancer Centre at University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Becker
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Kluth
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Rink
authors.affiliation: Martini Clinic, Prostate Cancer Centre at University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Steuber
authors.affiliation: Department of Urology, Vivantes Auguste-Viktoria-Klinikum, Berlin, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Zacharias
authors.affiliation: Department of Urology, Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Margit
authors.initials: M
authors.lastname: Fisch
authors.affiliation: Martini Clinic, Prostate Cancer Centre at University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Graefen
authors.affiliation: Department of Urology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Martini Clinic, Prostate Cancer Centre at University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Felix K-H
authors.initials: FK
authors.lastname: Chun
mesh_terms: D000368:Aged; D003658:Decision Making, Computer-Assisted; D003661:Decision Support Techniques; D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D049451:Nomograms; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*
keywords: Decision curve analysis; External validation; High-risk prostate cancer; Nomogram; Radical prostatectomy; Risk stratification