title: Tumor diameter accurately predicts perioperative outcomes in T1 renal cancer treated with robot-assisted partial nephrectomy.
abstract: OBJECTIVE
  To compare diameter as a continuous variable with categorical R.E.N.A.L. nephrometry score (RNS) in predicting surgical outcomes of robotic partial nephrectomy (RPN).
  
  
  METHODS
  We retrospectively reviewed consecutive patients receiving RPN at our institution between July 2007 and June 2014 (n = 286). Three separate multivariate analyses were performed to assess the relationship between RNS components (R = radius, E = endophyticity, N = nearness to collecting system, L = location relative to polar lines), total RNS, and diameter as a continuous variable with operating time, warm ischemia time (WIT), and estimated blood loss (EBL). Each linear regression model's quality of fit to the data was assessed with coefficients of determination (R2).
  
  
  RESULTS
  Continuous tumor diameter and total RNS were each significantly correlated to operative time, EBL, and WIT (p < 0.001). Categorical R related to operative time (R = 2 vs. R = 1, p = 0.001; R = 3 vs. R = 1, p = 0.001) and WIT (R = 2 vs. R = 1, p = 0.003; R = 3 vs. R = 1, p = 0.016), but not to EBL. For each of these outcomes, diameter outperformed both R and total RNS, as assessed by R2. Age, body mass index, Charlson Comorbidity Index, and anterior versus posterior location did not correlate with surgical outcomes.
  
  
  CONCLUSIONS
  In this series of RPN from a high-volume center, surgical outcomes more closely related to tumor diameter than RNS. While RNS provides surgeons a standardized tool for preoperative planning of renal masses, tumor size may be employed as a more familiar measurement when counseling patients on potential outcomes.
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA. potretzkea@wudosis.wustl.edu.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Potretzke
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Theodora A
authors.initials: TA
authors.lastname: Potretzke
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: B Alexander
authors.initials: BA
authors.lastname: Knight
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Vetter
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Park
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: Grecori
authors.initials: G
authors.lastname: Anderson
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: Sam B
authors.initials: SB
authors.lastname: Bhayani
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, 4960 Children's Place, Campus Box 8242, St. Louis, MO, 63110, USA.
authors.forename: R Sherburne
authors.initials: RS
authors.lastname: Figenshau
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012371:Robotics / Q000331:legislation & jurisprudence*; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Kidney neoplasms; Nephrectomy; Partial nephrectomy; Renal cancer; Robotics