title: The association between nerve sparing and a positive surgical margin during radical prostatectomy.
abstract: OBJECTIVE
  A positive surgical margin (SM) during radical prostatectomy (RP) increases risk of biochemical recurrence. We evaluated the effect of nerve-sparing procedures on risk of positive SM for pT2- and pT3-category tumors. We hypothesized that nerve sparing would increase rates of pT2 positive margins.
  
  
  METHODS
  We evaluated a historical cohort of 9,915 consecutive RP patients treated at The Ottawa Hospital or Memorial Sloan-Kettering Cancer Center from 2000 to 2010. Patients underwent open, laparoscopic, or robotic RP. The primary outcome was presence of a positive SM stratified by pathologic pT2 and pT3 categories. The association between nerve sparing and positive margin was adjusted for prostate-specific antigen, RP Gleason sum, surgical modality, surgical date, and location in the multivariable model.
  
  
  RESULTS
  Of 6,120 eligible patients, 3,958 (64.7%) had open RP, 1,566 (25.6%) had laparoscopic RP, and 596 (9.7%) had robotic RP. Approximately 8.6% (363/4,199) of patients with pT2-category disease and 25.2% (485/1,921) of patients with pT3-category disease had a positive margin. Patients with pT2-category disease who underwent a bilateral nerve-sparing procedure were more likely to have a positive margin when compared with those who underwent nerve resection on multivariable analysis (relative risk [RR] = 1.52, 95% CI: 0.97-2.39) after adjusting for confounders. Patients with pT3-category disease who underwent a bilateral nerve-sparing procedure had no associated increase in risk of positive margin after adjustment for other variables (RR = 0.96, 95% CI: 0.80-1.16). Prostate incision into tumor (pT2R1) was significantly more likely in patients treated with robotic surgery (RR = 1.76, 95% CI: 1.25-2.48) than in those with open surgery. There was no difference between laparoscopic and open RP (RR = 0.86, 95% CI: 0.65-1.12).
  
  
  CONCLUSIONS
  Bilateral nerve sparing is associated with increased risk of positive SMs in patients with pathologic T2-category disease during RP.
authors.affiliation: Department of Urology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Preston
authors.affiliation: Department of Surgery, The Ottawa Hospital, General Campus, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Rodney H
authors.initials: RH
authors.lastname: Breau
authors.affiliation: Department of Urology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Lantz
authors.affiliation: Department of Surgery, The Ottawa Hospital, General Campus, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Morash
authors.affiliation: Department of Surgery, The Ottawa Hospital, General Campus, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Gerridzen
authors.affiliation: Research Methods Unit, Capital Health Authority, Halifax, Nova Scotia, Canada.
authors.forename: Steve
authors.initials: S
authors.lastname: Doucette
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Ranjeeta
authors.initials: R
authors.lastname: Mallick
authors.affiliation: Department of Urology, Urology Service, Memorial Sloan-Kettering Cancer Center, New York, NY.
authors.forename: James A
authors.initials: JA
authors.lastname: Eastham
authors.affiliation: Department of Surgery, The Ottawa Hospital, General Campus, University of Ottawa, Ottawa, Ontario, Canada. Electronic address: icagiannos@ottawahospital.on.ca.
authors.forename: Ilias
authors.initials: I
authors.lastname: Cagiannos
mesh_terms: D015331:Cohort Studies; D006801:Humans; D010535:Laparoscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D065287:Robotic Surgical Procedures / Q000379:methods
keywords: Carcinoma; Nerves; Prostate; Prostatectomy