title: Location, extent and number of positive surgical margins do not improve accuracy of predicting prostate cancer recurrence after radical prostatectomy.
abstract: OBJECTIVE
  Positive surgical margins increase the risk of biochemical recurrence after radical prostatectomy by 2 to 4-fold. The risk of biochemical recurrence may be influenced by the anatomical location and extent of positive surgical margins. In a multicenter study we analyzed the predictive usefulness of several subclassifications of positive surgical margins.
  
  
  METHODS
  The clinical information and followup data of 7,160 patients treated with radical prostatectomy alone at 1 of 3 institutions between 1995 and 2006 were modeled using Cox proportional hazards regression analysis for biochemical recurrence. Positive surgical margins were analyzed as solitary vs multiple, focal vs extensive and apical location vs other. The usefulness of these subclassifications was assessed by the improvement in predictive accuracy of nomograms containing these parameters compared to one in which the surgical margin was modeled simply as positive vs negative.
  
  
  RESULTS
  The 7-year progression-free probability was 60% in patients with positive surgical margins. A positive surgical margin was significantly associated with biochemical recurrence (HR 2.3, p <0.001) after adjusting for age, prostate specific antigen, pathological Gleason score, pathological stage and year of surgery. An increased risk of biochemical recurrence was associated with multiple vs solitary positive surgical margins (adjusted HR 1.4, p = 0.002) and extensive vs focal positive surgical margins (adjusted HR 1.3, p = 0.004) on multivariable analysis. However, neither parameter improved the predictive accuracy of a nomogram compared to one in which surgical margin status was modeled as positive vs negative (concordance index 0.851 vs 0.850 vs 0.850).
  
  
  CONCLUSIONS
  The number and extent of positive surgical margin significantly influence the risk of biochemical recurrence after radical prostatectomy. However, the empirical prognostic usefulness of subclassifications of positive surgical margins is limited.
authors.affiliation: Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA. stephea2@ccf.org
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Stephenson
authors.forename: David P
authors.initials: DP
authors.lastname: Wood
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kattan
authors.forename: Eric A
authors.initials: EA
authors.lastname: Klein
authors.forename: Peter T
authors.initials: PT
authors.lastname: Scardino
authors.forename: James A
authors.initials: JA
authors.lastname: Eastham
authors.forename: Brett S
authors.initials: BS
authors.lastname: Carver
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D011237:Predictive Value of Tests; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D015203:Reproducibility of Results