title: Positive surgical margins after robotic assisted radical prostatectomy: a multi-institutional study.
abstract: OBJECTIVE
  Positive surgical margins are an independent predictive factor for biochemical recurrence after radical prostatectomy. We analyzed the incidence of and associative factors for positive surgical margins in a multi-institutional series of 8,418 robotic assisted radical prostatectomies.
  
  
  METHODS
  We analyzed the records of 8,418 patients who underwent robotic assisted radical prostatectomy at 7 institutions. Of the patients 323 had missing data on margin status. Positive surgical margins were categorized into 4 groups, including apex, bladder neck, posterolateral and multifocal. The records of 6,169 patients were available for multivariate analysis. The variables entered into the logistic regression models were age, body mass index, preoperative prostate specific antigen, biopsy Gleason score, prostate weight and pathological stage. A second model was built to identify predictive factors for positive surgical margins in the subset of patients with organ confined disease (pT2).
  
  
  RESULTS
  The overall positive surgical margin rate was 15.7% (1,272 of 8,095 patients). The positive surgical margin rate for pT2 and pT3 disease was 9.45% and 37.2%, respectively. On multivariate analysis pathological stage (pT2 vs pT3 OR 4.588, p<0.001) and preoperative prostate specific antigen (4 or less vs greater than 10 ng/ml OR 2.918, p<0.001) were the most important independent predictive factors for positive surgical margins after robotic assisted radical prostatectomy. Increasing prostate weight was associated with a lower risk of positive surgical margins after robotic assisted radical prostatectomy (OR 0.984, p<0.001) and a higher body mass index was associated with a higher risk of positive surgical margins (OR 1.032, p<0.001). For organ confined disease preoperative prostate specific antigen was the most important factor that independently correlated with positive surgical margins (4 or less vs greater than 10 ng/ml OR 3.8, p<0.001).
  
  
  CONCLUSIONS
  The prostatic apex followed by a posterolateral site was the most common location of positive surgical margins after robotic assisted radical prostatectomy. Factors that correlated with cancer aggressiveness, such as pathological stage and preoperative prostate specific antigen, were the most important factors independently associated with an increased risk of positive surgical margins after robotic assisted radical prostatectomy.
authors.affiliation: Global Robotics Institute, Florida Hospital-Celebration Health, University of Central Florida College of Medicine, Orlando, Florida, USA. Vipul.patel.md@flhosp.org
authors.forename: Vipul R
authors.initials: VR
authors.lastname: Patel
authors.forename: Rafael F
authors.initials: RF
authors.lastname: Coelho
authors.forename: Bernardo
authors.initials: B
authors.lastname: Rocco
authors.forename: Marcelo
authors.initials: M
authors.lastname: Orvieto
authors.forename: Ananthakrishnan
authors.initials: A
authors.lastname: Sivaraman
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Palmer
authors.forename: Darien
authors.initials: D
authors.lastname: Kameh
authors.forename: Luigi
authors.initials: L
authors.lastname: Santoro
authors.forename: Geoff D
authors.initials: GD
authors.lastname: Coughlin
authors.forename: Michael
authors.initials: M
authors.lastname: Liss
authors.forename: Wooju
authors.initials: W
authors.lastname: Jeong
authors.forename: John
authors.initials: J
authors.lastname: Malcolm
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Stern
authors.forename: Saurabh
authors.initials: S
authors.lastname: Sharma
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Zorn
authors.forename: Sergey
authors.initials: S
authors.lastname: Shikanov
authors.forename: Arieh L
authors.initials: AL
authors.lastname: Shalhav
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Zagaja
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Ahlering
authors.forename: Koon H
authors.initials: KH
authors.lastname: Rha
authors.forename: David M
authors.initials: DM
authors.lastname: Albala
authors.forename: Michael D
authors.initials: MD
authors.lastname: Fabrizio
authors.forename: David I
authors.initials: DI
authors.lastname: Lee
authors.forename: Sanket
authors.initials: S
authors.lastname: Chauhan
mesh_terms: D006801:Humans; D008297:Male; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D012371:Robotics