title: Visceral obesity is associated with better recurrence-free survival after curative surgery for Japanese patients with localized clear cell renal cell carcinoma.
abstract: OBJECTIVE
  To investigate the prognostic significance of visceral obesity to predict recurrence after curative surgery for Japanese patients with localized renal cell carcinoma.
  
  
  METHODS
  The data of 285 patients who underwent curative surgery for localized renal cell carcinoma were retrospectively reviewed. Median follow-up was 36.7 months. The association between visceral obesity and recurrence-free survival rate was evaluated using the Kaplan-Meier method and Cox regression models. Visceral fat area at the level of the umbilicus measured using pre-operative computed tomography was used as an index of visceral obesity.
  
  
  RESULTS
  Twenty-nine patients (10.2%) experienced recurrence. Five-year recurrence-free survival rates were 91.3% in high visceral fat area group (≥ 120 cm(2)) and 76.9% in low visceral fat area group (<120 cm(2)) (P = 0.037); however, visceral fat area was not an independent predictor of recurrence-free survival in multivariate analysis. In the patients with clear cell renal cell carcinoma, 28 patients (11.6%) experienced recurrence. Five-year recurrence-free survival rates were 88.7% in high visceral fat area group and 71.0% in low visceral fat area group (P = 0.043), and visceral fat area was an independent predictor of recurrence-free survival (hazard ratio: 1.974, P = 0.042) as well as C-reactive protein, Fuhrman nuclear grade, tumor size and microvascular invasion. In patients with organ confined clear cell renal cell carcinoma in particular, visceral fat area was also a useful and independent predictor of recurrence-free survival (hazard ratio: 2.807, P = 0.038). Body mass index was not useful in either cohort.
  
  
  CONCLUSIONS
  High visceral fat area was a positive predictive biomarker for better recurrence-free survival after curative surgeries for localized clear cell renal cell carcinomas; however, body mass index was not a predictor.
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Gou
authors.initials: G
authors.lastname: Kaneko
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo akiram@a8.keio.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Miyajima
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Yuge
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yazawa
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Mizuno
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kikuchi
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Jinzaki
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo.
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Oya
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data*; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D056128:Obesity, Abdominal / Q000175:diagnosis*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies
keywords: clear cell renal cell carcinoma; obesity; recurrence-free survival; renal cell carcinoma; visceral obesity