title: The effect of wide resection during radical prostatectomy on surgical margins.
abstract: BACKGROUND
  The impact of nerve-sparing on positive surgical margins during radical prostatectomy (RP) remains unclear. The objective of this study was to determine the incidence of positive surgical margins with a wide resection compared to a nerve-sparing technique.
  
  
  METHODS
  A consecutive, single-surgeon patient cohort treated between August 2010 and November 2014 was reviewed. A standardized surgical approach of lobe-specific nerve-spare or wide resection was performed. Lobe-specific margin status and tumour stage were obtained from pathology reports. Univariable and multivariable associations between nerve management technique and lobe-specific positive surgical margin were determined.
  
  
  RESULTS
  Of 388 prostate lobes, wide resection was performed in 105 (27%) and nerve-sparing in 283 (73%). In 273 lobes without extra-prostatic extension (EPE), 0 of 52 (0%) had a positive margin when wide resection was performed compared to 20 of 221 (9%) if nerve-sparing was performed (p=0.02). In 115 lobes with EPE, 11 of 53 (21%) had a positive margin if wide resection was performed compared to 28 of 62 (45%) if nerve-sparing was performed (p=0.006). In multivariable analysis, the risk of a positive margin was decreased among patients who received wide resection as compared to nerve-spare (RR 0.43, 95% CI 0.26-0.71; p=0.001).
  
  
  CONCLUSIONS
  Surgical techniques to reduce positive surgical margins have become increasingly important as more patients with high-risk cancer are selecting surgery. The risk of a positive margin was greatly reduced using a standardized wide resection technique compared to nerve-sparing.
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada;; University of Ottawa, ON, Canada;; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors.forename: Luke T
authors.initials: LT
authors.lastname: Lavallée
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Stokl
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors.forename: Sonya
authors.initials: S
authors.lastname: Cnossen
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors.forename: Ranjeeta
authors.initials: R
authors.lastname: Mallick
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada;; University of Ottawa, ON, Canada;
authors.forename: Chris
authors.initials: C
authors.lastname: Morash
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada;; University of Ottawa, ON, Canada;
authors.forename: Ilias
authors.initials: I
authors.lastname: Cagiannos
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada;; University of Ottawa, ON, Canada;; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors.forename: Rodney H
authors.initials: RH
authors.lastname: Breau