title: Impact of body mass index in Korean patients with renal cell carcinoma.
abstract: OBJECTIVE
  The aim of the current study was to examine the impact of preoperative body mass index (BMI) in Korean patients with surgically treated renal cell carcinoma (RCC).
  
  
  METHODS
  From 1994 to 2008, a total of 1,487 patients underwent nephrectomy for RCC. All patients were classified into three groups according to Asian BMI classification by Asia Cohort Consortium: <18.5, 18.5 to <25, and 25 kg/m(2) or greater group, which represents the underweight (n = 42, 2.8%), normal (n = 833, 56.0%), and obesity (n = 612, 41.2%) group, respectively. Survival analyses and predictive factors for cancer-specific survival among the three groups were evaluated. Subgroup survival analysis of organ-confined and advanced disease was performed.
  
  
  RESULTS
  An overall median follow-up was 54.8 months. Mean ± SE estimated cancer-specific survival in all patients at 5 and 10 years was 88.0 ± 1.0% and 81.4 ± 1.4%, respectively. In the multivariate model after adjusting preoperative and postoperative variables, the underweight group had a significantly worse prognosis than the normal group (hazard ratio (HR): 2.17, 95% confidence interval (95% CI): 1.16-4.08, p = 0.016), meanwhile the obesity group was associated with improved survival (HR: 0.66, 95% CI: 0.45-0.96, p = 0.032). In the subgroup analysis of advanced RCC, obesity was associated with better prognosis than the normal group after applying multivariate analysis (p = 0.001).
  
  
  CONCLUSIONS
  Preoperative underweight could be a new independent factor to predict unfavorable cancer-specific survival in Korean patients with RCC treated by surgery. Moreover, obesity was verified to be associated with superior cancer-specific survival.
authors.affiliation: Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-dong, Gangnam-gu, Seoul, Korea.
authors.forename: Hyun Hwan
authors.initials: HH
authors.lastname: Sung
authors.forename: Seong Soo
authors.initials: SS
authors.lastname: Jeon
authors.forename: Seo Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Byong Chang
authors.initials: BC
authors.lastname: Jeong
authors.forename: Seong Il
authors.initials: SI
authors.lastname: Seo
authors.forename: Hyun Moo
authors.initials: HM
authors.lastname: Lee
authors.forename: Han-Yong
authors.initials: HY
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000453:epidemiology* / Q000401:mortality / Q000601:surgery; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D007680:Kidney Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000601:surgery; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009392:Nephrectomy; D009765:Obesity / Q000150:complications*; D011379:Prognosis; D011446:Prospective Studies; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D016896:Treatment Outcome