title: Impact of tumour morphology on renal function decline after partial nephrectomy.
abstract: OBJECTIVE
  To examine the association of renal morphology with renal function after partial nephrectomy (PN).
  
  
  METHODS
  We conducted a multi-institutional retrospective analysis of 322 PNs performed between 2003 and 2011. The RENAL nephrometry score for each lesion was determined and the estimated glomerular filtration rate (eGFR) was calculated preoperatively and at last follow-up. We divided patients into two RENAL nephrometry score groups, low (<8) and high (≥8), and analysed and compared the outcomes of each group. The primary outcome was median change in eGFR between preoperative and last follow-up (ΔeGFR). The secondary outcome was eGFR <60 mL/min/1.73 m(2) at last follow-up. Multivariable analysis was conducted to evaluate the risk factors for eGFR <60 mL/min/1.73 m(2) at last follow-up.
  
  
  RESULTS
  The median (interquartile range) follow-up was 25.2 (13.5-39.3) months. Low (n = 165) and high (n = 157) RENAL score groups were well-matched for baseline eGFR. The median tumour size (4.2 vs 2.4 cm, P < 0.001) was greater for the high group. In all, 64% of the low and 88.2% of the high RENAL score group (P < 0.001) had decreased eGFR at last follow-up. Median eGFR was -7 for the low vs -13.8 mL/min/1.73 m(2) for the high group (P = 0.001); eGFR <60 mL/min/1.73 m(2) at last follow-up was 27.3% for the low vs 37.6% for the high group (P = 0.057). Linear regression analysis showed that for each 1-point increase in RENAL score, there was 2.5% decrease in eGFR (P = 0.002); for each 1-cm increase in tumour size, there was 1.8% decrease in eGFR (P = 0.013). Area under curve analyses showed no significant difference between RENAL score and tumour size for prediction of de novo eGFR <60 mL/min/1.73 m(2) (P = 0.920) and ΔeGFR ≥50% (P = 0.85). Multivariable analysis showed that increasing RENAL score (odds ratio [OR] 1.24, P = 0.046) and decreasing preoperative eGFR (OR 1.10, P < 0.001) were risk factors for eGFR <60 mL/min/1.73 m(2) at last follow-up.
  
  
  CONCLUSIONS
  Increasing RENAL nephrometry score is an independent risk factor for eGFR <60 mL/min/1.73 m(2) after PN. RENAL nephrometry score may serve as an additional measure for risk stratification before PN, but further investigation is required.
authors.affiliation: Department of Urology, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Mehrazin
authors.forename: Kerrin L
authors.initials: KL
authors.lastname: Palazzi
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Kopp
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Colangelo
authors.forename: Sean P
authors.initials: SP
authors.lastname: Stroup
authors.forename: James H
authors.initials: JH
authors.lastname: Masterson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Liss
authors.forename: Seth A
authors.initials: SA
authors.lastname: Cohen
authors.forename: Ramzi
authors.initials: R
authors.lastname: Jabaji
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Park
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Patterson
authors.forename: James O
authors.initials: JO
authors.lastname: L'Esperance
authors.forename: Ithaar H
authors.initials: IH
authors.lastname: Derweesh
mesh_terms: D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007680:Kidney Neoplasms / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000379:methods*; D011184:Postoperative Period; D051437:Renal Insufficiency / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012189:Retrospective Studies