title: Stronger association between obesity and biochemical progression after radical prostatectomy among men treated in the last 10 years.
abstract: BACKGROUND
  Prior prospective cohort studies found that obesity was associated with increased risk of prostate cancer death. However, in the last 20 years dramatic changes in both the extent of obesity and prostate cancer screening and treatment have occurred. Whether the association between obesity and aggressive disease has changed as a result of these temporal changes is unclear.
  
  
  METHODS
  The study population consisted of 2,832 men treated by anatomic radical retropubic prostatectomy between 1985 and 2004 by a single surgeon. We evaluated the associations of obesity (body mass index > or =30 kg/m(2))with tumor stage and grade using logistic regression and with biochemical progression using Cox proportional hazards regression. We examined whether these associations have changed over the last 20 years.
  
  
  RESULTS
  On multivariable analysis, the strength of the positive association between obesity and high-grade disease increased over time whereas the strength of the positive association between obesity and positive surgical margins decreased over time. The strength of the positive association between obesity and extraprostatic extension fluctuated over time, although the strongest and only statistically significant association was among men treated since 2000. The association between obesity and biochemical progression was strongest among men treated since 1995 (relative risk, 1.90; 95% confidence interval, 1.09-3.30; P = 0.02).
  
  
  CONCLUSIONS
  In the current study, with the exception of positive surgical margins, the positive association between obesity and high-grade disease, advanced stage, and biochemical progression after radical retropubic prostatectomy was in general strongest among men treated in the last 10 years. The reasons for these findings are not clear, although factors possibly related to prostate-specific antigen-based screening and/or other temporal changes in prostate cancer diagnosis and treatment may play a role.
authors.affiliation: Departments of Urology, and Pathology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA. sfreedl1@jhmi.edu
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Freedland
authors.forename: William B
authors.initials: WB
authors.lastname: Isaacs
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Mangold
authors.forename: Sindy K
authors.initials: SK
authors.lastname: Yiu
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Grubb
authors.forename: Alan W
authors.initials: AW
authors.lastname: Partin
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Epstein
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Walsh
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
mesh_terms: D015992:Body Mass Index; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000150:complications / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis
chemical_list: D017430:Prostate-Specific Antigen