title: Obesity is associated with an improved cancer-specific survival, but an increased rate of postoperative complications after surgery for renal cell carcinoma.
abstract: OBJECTIVE
  This study aimed to assess the impact of preoperative body mass index (BMI) on postoperative complications, cancer-specific survival (CSS) and overall survival (OS) in patients operated for renal cell carcinoma (RCC).
  
  
  METHODS
  The study included 397 patients with BMI values, who underwent surgery for RCC between 1 January 1997 and 31 December 2010. Obese patients (BMI > 30 kg/m(2)) were compared to non-obese patients (BMI < 30 kg/m(2)) in regard to CSS and OS. A Cox proportional hazard model was used for the multivariate survival analyses. The mean age of the patients was 62.1 years. There were 259 males (65%) and 325 patients (82%) were non-obese. Mean BMI was 26 kg/m(2).
  
  
  RESULTS
  In the total material, CSS was 94.7% for obese patients and 74.8% for non-obese patients (p = 0.06). The obese group had significantly better CSS in univariate analysis for presumed radically treated disease (pT1-3N0M0). Obesity was a significant protective prognostic factor in multivariate analysis. An accelerating protective effect for CSS was found with increasing levels of BMI. In regard to OS, no difference was found between the two groups. Obese patients had a significantly lower age, and a higher rate of diabetes mellitus, hypertension and incidental detection. Obese patients had a significantly higher total incidence of postoperative complications, but not surgery-related complications.
  
  
  CONCLUSIONS
  In this material, increasing BMI was associated with improved CSS for presumed radically treated patients. However, obese patients had a higher total rate of postoperative complications.
authors.affiliation: Department of Urology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Ase J
authors.initials: AJ
authors.lastname: Rogde
authors.forename: Gigja
authors.initials: G
authors.lastname: Gudbrandsdottir
authors.forename: Karin M
authors.initials: KM
authors.lastname: Hjelle
authors.forename: Kristoffer E
authors.initials: KE
authors.lastname: Sand
authors.forename: Leif
authors.initials: L
authors.lastname: Bostad
authors.forename: Christian
authors.initials: C
authors.lastname: Beisland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000150:complications / Q000401:mortality* / Q000601:surgery; D016022:Case-Control Studies; D003920:Diabetes Mellitus; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D007680:Kidney Neoplasms / Q000150:complications / Q000401:mortality* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009392:Nephrectomy; D009765:Obesity / Q000150:complications*; D011183:Postoperative Complications / Q000453:epidemiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015996:Survival Rate