title: External validation of nomogram predicting the probability of specimen-confined disease (pT2-3a, R0N0) in patients undergoing radical prostatectomy and pelvic lymph node dissection.
abstract: BACKGROUND
  Before radical prostatectomy (RP), a nomogram [Briganti et al., Eur Urol 2012;61:584-592] permits to measure the probability of specimen-confined (SC) disease (pT2-pT3a, node negative with negative margins) in high-risk prostate cancer (PCa). The aim of our study was to perform an external validation of this nomogram.
  
  
  METHODS
  Between 2007 and 2011, 623 patients with high-risk PCa (prostate-specific antigen (PSA) >20 ng/ml and/or biopsy Gleason score ≥8 and/or clinical stage T3) underwent RP and pelvic lymph node dissection at tertiary referral centers. Multivariable logistic regression models predicting the presence of SC disease were built in; we then used the area under curve of the receiver operating characteristic analysis to quantify accuracy of the nomogram to predict SC disease. The extent of over- or underestimation was evaluated within calibration plots.
  
  
  RESULTS
  29% (181/623) of men had SC disease at RP. Preoperative PSA, biopsy Gleason score and stage differed significantly (all p < 0.001) between men with SC disease and those without. External validation of the nomogram showed an acceptable accuracy (area under curve: 66.3, 95% CI 62.4-70%) and a perfect calibration plot.
  
  
  CONCLUSIONS
  The external cohort validates the original nomogram, with perfect calibration characteristics. The adequate although reduced accuracy may reflect the wide spectrum and behavior of the so-called high-risk PCa.
authors.affiliation: Department of Urology, University of Perugia, Perugia, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Mearini
authors.forename: Mauro
authors.initials: M
authors.lastname: Gacci
authors.forename: Omar
authors.initials: O
authors.lastname: Saleh
authors.forename: Cosimo
authors.initials: C
authors.lastname: De Nunzio
authors.forename: Riccardo
authors.initials: R
authors.lastname: Schiavina
authors.forename: Alchiede
authors.initials: A
authors.lastname: Simonato
authors.forename: Andrea
authors.initials: A
authors.lastname: Tubaro
authors.forename: Giorgio
authors.initials: G
authors.lastname: Carmignani
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Mirone
authors.forename: Marco
authors.initials: M
authors.lastname: Carini
authors.forename: Vittorio
authors.initials: V
authors.lastname: Bini
authors.forename: Massimo
authors.initials: M
authors.lastname: Porena
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D015331:Cohort Studies; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D049451:Nomograms; D011336:Probability; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D012372:ROC Curve; D012044:Regression Analysis; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen