title: Positive surgical margins in robot-assisted partial nephrectomy: a multi-institutional analysis of oncologic outcomes (leave no tumor behind).
abstract: OBJECTIVE
  Expanding indications for robot-assisted partial nephrectomy raise major oncologic concerns for positive surgical margins. Previous reports showed no correlation between positive surgical margins and oncologic outcomes. We report a multi-institutional experience with the oncologic outcomes of positive surgical margins on robot-assisted partial nephrectomy.
  
  
  METHODS
  Pathological and clinical followup data were reviewed from an institutional review board approved, prospectively maintained joint database from 5 institutions. Tumors with malignant pathology were isolated and statistically analyzed for demographics and oncologic followup. The log rank test was used to compare recurrence-free and metastasis-free survival between patients with positive and negative surgical margins. The proportional hazards method was used to assess the influence of multiple factors, including positive surgical margins, on recurrence and metastasis.
  
  
  RESULTS
  A total of 943 robot-assisted partial nephrectomies for malignant tumors were successfully completed. Of the patients 21 (2.2%) had positive surgical margins on final pathological assessment, resulting in 2 groups, including the 21 with positive surgical margins and 922 with negative surgical margins. Positive surgical margin cases had higher recurrence and metastasis rates (p<0.001). As projected by the Kaplan-Meier method in the population as a whole at followup out to 63.6 months, 5-year recurrence-free and metastasis-free survival was 94.8% and 97.5%, respectively. There was a statistically significant difference in recurrence-free and metastasis-free survival between patients with positive and negative surgical margins (log rank test<0.001), which favored negative surgical margins. Positive surgical margins showed an 18.4-fold higher HR for recurrence when adjusted for multiple tumors, tumor size, tumor growth pattern and pathological stage.
  
  
  CONCLUSIONS
  Positive surgical margins on final pathological evaluation increase the HR of recurrence and metastasis. In addition to pathological and molecular tumor characteristics, this should be considered to plan appropriate management.
authors.affiliation: Center for Laparoscopic and Robotic Surgery, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Ali
authors.initials: A
authors.lastname: Khalifeh
authors.forename: Jihad H
authors.initials: JH
authors.lastname: Kaouk
authors.forename: Sam
authors.initials: S
authors.lastname: Bhayani
authors.forename: Craig
authors.initials: C
authors.lastname: Rogers
authors.forename: Michael
authors.initials: M
authors.lastname: Stifelman
authors.forename: Youssef S
authors.initials: YS
authors.lastname: Tanagho
authors.forename: Ramesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gorin
authors.forename: Ganesh
authors.initials: G
authors.lastname: Sivarajan
authors.forename: Dinesh
authors.initials: D
authors.lastname: Samarasekera
authors.forename: Mohamad E
authors.initials: ME
authors.lastname: Allaf
mesh_terms: D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000379:methods*; D011446:Prospective Studies; D012371:Robotics; D016896:Treatment Outcome
keywords: NSM; PN; PSM; RCC; RPN; carcinoma; kidney; negative surgical margin; nephrectomy; partial nephrectomy; pathology; positive surgical margin; renal cell; renal cell carcinoma; robot-assisted laparoscopic PN; robotics