title: Prostate weight: an independent predictor for positive surgical margins during robotic-assisted laparoscopic radical prostatectomy.
abstract: BACKGROUND
  Pre-operative prediction of pathological stage represents the cornerstone of prostate cancer management. Patient counseling is routinely based on pre-operative PSA, Gleason score and clinical stage. In this study, we evaluated whether prostate weight (PW) is an independent predictor of extracapsular extension (ECE) and positive surgical margin (PSM).
  
  
  METHODS
  Between February 2003 and November 2006, 709 men underwent robotic-assisted laparoscopic radical prostatectomy (RLRP). Pre-operative parameters (patient age, pre-operative PSA, biopsy Gleason score, clinical stage) as well as pathological data (prostate weight, pathological stage) were prospectively gathered after internal-review board (IRB) approval. Evaluation of the influence of these variables on ECE and PSM outcomes were assessed using both univariate and multivariate logistic regression analysis.
  
  
  RESULTS
  Mean overall patient age, pre-operative PSA and PW were 59.6 years, 6.5 ng/ml and 52.9 g (range 5.5 g-198.7 g), respectively. Of the 393, 209 and 107 men with PW < 50 g, 50 g-< 70 g and < 70 g, ECE was observed in 20.1%, 15.3% and 9.3%, respectively (p = 0.015). In the same patient cohorts, PSM was observed in 25.4%, 14.4% and 7.5%, respectively (p < 0.001). In a multivariate logistic regression analysis, PW, in addition to pre-operative PSA, biopsy Gleason score and clinical stage, was an independent risk factor for ECE (p < 0.001). Similarly, in multi-variate analysis, PW was observed to be a risk factor for PSM (p < 0.001).
  
  
  CONCLUSIONS
  PW is an independent predictor of both ECE and PSM, with an inverse relationship having been demonstrated between both variables. PW should be considered when counseling patients with prostate cancer treatment.
authors.affiliation: Section of Urology, University of Chicago Pritzker School of Medicine, Chicago, Illinois 60637, USA.
authors.forename: Lambda P
authors.initials: LP
authors.lastname: Msezane
authors.forename: Ofer N
authors.initials: ON
authors.lastname: Gofrit
authors.forename: Shang
authors.initials: S
authors.lastname: Lin
authors.forename: Arieh L
authors.initials: AL
authors.lastname: Shalhav
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Zagaja
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Zorn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009929:Organ Size; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology*; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D012371:Robotics / Q000379:methods*; D016896:Treatment Outcome