title: Surgical margin length and location affect recurrence rates after robotic prostatectomy.
abstract: BACKGROUND
  Robotic-assisted laparoscopic radical prostatectomy is a current standard treatment for localized prostate cancer, with treatment failure defined by biochemical recurrence (BCR). Open radical prostatectomy series have identified the presence of a positive surgical margin (PSM) as a predictor of long-term recurrence, a measure that is affected by the surgeon׳s skill. We evaluate the effect of PSM parameters on BCR rates from robotic-assisted laparoscopic radical prostatectomy, across 3 high-volume institutions.
  
  
  METHODS
  De-identifiable clinicopathological and histopathological data were prospectively collected for 4,001 patients with at least 3 years of follow-up. Kaplan-Meier plots and 3 statistical models were used to evaluate the effect of margin parameters on BCR, via crude rates, traditional multivariable Cox regression, and a propensity-adjusted Cox regression model.
  
  
  RESULTS
  Overall, 37% of men with a PSM developed BCR compared with 10% of men with negative margins (hazard ratio [HR] = 1.81, 95% CI: 1.47-2.22). Length ≥3 mm or a multifocal positive margin was associated with a higher risk of BCR compared with negative margin cases. On multivariable Cox regression analysis of the positive margin cohort, only apical margins significantly predicted BCR relative to basal margins (HR = 2.03, 95% CI: 1.01-4.09), whereas there was no significant difference in BCR rates for posterolateral margins relative to basal margins (HR = 1.62, 95% CI: 0.84-3.11). Propensity-adjusted modeling confirmed a greater effect of apical compared with posterolateral PSM.
  
  
  CONCLUSIONS
  A PSM length ≥3 mm is predictive of BCR, as is to a lesser extent multiple positive margins. In contrast to open prostatectomy series, posterolateral margins carry a smaller risk of BCR compared with apical margins.
authors.affiliation: Department of Urology, Cambridge University Hospitals NHS Trust, Cambridge, UK; Cancer Research UK Cambridge Institute, Cambridge, UK.
authors.forename: Harveer S
authors.initials: HS
authors.lastname: Dev
authors.affiliation: Department of Urology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Wiklund
authors.affiliation: Department of Urology, Global Robotics Institute, Orlando, FL.
authors.forename: Vipul
authors.initials: V
authors.lastname: Patel
authors.affiliation: Cancer Research UK Cambridge Institute, Cambridge, UK; Cancer Research Unit, Division of Health Sciences, University of Warwick, Coventry, UK.
authors.forename: Deepak
authors.initials: D
authors.lastname: Parashar
authors.affiliation: Department of Urology, Global Robotics Institute, Orlando, FL.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Palmer
authors.affiliation: Department of Urology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Tommy
authors.initials: T
authors.lastname: Nyberg
authors.affiliation: Department of Urology, University of California, Irvine, CA.
authors.forename: Doug
authors.initials: D
authors.lastname: Skarecky
authors.affiliation: Department of Urology, Cambridge University Hospitals NHS Trust, Cambridge, UK; Cancer Research UK Cambridge Institute, Cambridge, UK.
authors.forename: David E
authors.initials: DE
authors.lastname: Neal
authors.affiliation: Department of Urology, University of California, Irvine, CA.
authors.forename: Tom
authors.initials: T
authors.lastname: Ahlering
authors.affiliation: Department of Urology, Karolinska University Hospital, Stockholm, Sweden; Surgical Intervention Trials Unit, Nuffield Department of Surgical Sciences, Oxford, UK. Electronic address: prasanna.sooriakumaran@nds.ox.ac.uk.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Sooriakumaran
mesh_terms: D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D012307:Risk Factors; D065287:Robotic Surgical Procedures; D025321:Surgery, Computer-Assisted
chemical_list: D017430:Prostate-Specific Antigen
keywords: Biochemical recurrence; Length; Location; Positive surgical margin; Robotic-assisted prostatectomy