title: Evaluation of positive surgical margins in patients undergoing robot-assisted and open radical prostatectomy according to preoperative risk groups.
abstract: OBJECTIVE
  Recent studies showed that robot-assisted radical prostatectomy (RARP) represents an oncologically safe procedure in patients with prostate cancer (PCa), where the rate of positive surgical margins (PSMs) might be lower in patients treated with RARP as compared with that of those undergoing the open approach (open RP [ORP]). The aim of this study is to analyze the rate of PSMs according to preoperative risk groups in a large cohort of patients treated with RARP and ORP in a single institution with standardized surgical technique and pathological examination.
  
  
  METHODS
  We evaluated 6,194 consecutive patients with PCa undergoing either ORP (71.1%) or RARP (28.9%) between 1992 and 2014. Logistic regression analyses were used to test the association between type of surgery and PSMs in each preoperative risk group (low vs. intermediate vs. high) after adjusting for confounders.
  
  
  RESULTS
  Overall, 21.6% patients had PSMs. RARP was associated with a lower rate of PSMs in low-risk (11.5 vs. 15.4%, P = 0.01), intermediate-risk (18.9 vs. 23.5%, P = 0.008), and high-risk patients (19.7 vs. 30.1%, P<0.001). In multivariable analyses, after stratification according to risk group categories, no difference in PSMs between RARP and ORP was observed for low-risk (odds ratio [OR] = 0.87, P = 0.46) and intermediate-risk patients (OR = 0.84, P = 0.19). Conversely, RARP was associated with lower odds of PSMs in high-risk patients (OR = 0.69, P = 0.04). Similar results were observed when our analyses were repeated after accounting for pathological characteristics, in patients treated between 2006 and 2014 and in a cohort of men treated by high-volume surgeons (all P≤ 0.03).
  
  
  CONCLUSIONS
  The introduction of RARP at our institution led to a significant reduction in the risk of PSMs in patients with PCa with high-risk disease.
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy. Electronic address: suardi.nazareno@hsr.it.
authors.forename: Nazareno
authors.initials: N
authors.lastname: Suardi
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy; Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada.
authors.forename: Paolo
authors.initials: P
authors.lastname: Dell'Oglio
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallina
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gandaglia
authors.affiliation: Department of Urology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy.
authors.forename: Nicolò
authors.initials: N
authors.lastname: Buffi
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Moschini
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Fossati
authors.affiliation: Department of Urology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lughezzani
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Department of Urology, University of Montreal Health Center, Montreal, Canada.
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
authors.affiliation: Division of Oncology/Unit of Pathology, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Freschi
authors.affiliation: Division of Oncology/Unit of Pathology, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Lucianò
authors.affiliation: Department of Urology, Medical University of Vienna and General Hospital, Vienna, Austria.
authors.forename: Shahrokh F
authors.initials: SF
authors.lastname: Shariat
authors.affiliation: Department of Urology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Guazzoni
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Gaboardi
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.affiliation: Division of Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
mesh_terms: D006801:Humans; D008297:Male; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D012307:Risk Factors; D012371:Robotics / Q000379:methods*
keywords: Positive surgical margins; Prostate cancer; Robot-assisted radical prostatectomy