title: Association of obesity with tumor characteristics and treatment failure of prostate cancer in African-American and European American men.
abstract: OBJECTIVE
  The impact of body mass index on tumor characteristics and treatment failure in prostate cancer is not well understood in diverse ethnic groups. We evaluated the effect of body mass index in African-American and European American patients from a radical prostatectomy cohort between 1995 and 2004 with regard to tumor histopathological characteristics and biochemical relapse-free survival.
  
  
  METHODS
  A total of 924 patients were studied to evaluate whether obese men (body mass index greater than 30) had different preoperative and postoperative tumor characteristics or biochemical relapse-free survival compared to nonobese men. There were 784 European American and 140 African-American patients analyzed using failure time models, adjusted for age, preoperative prostate specific antigen, tumor stage and race.
  
  
  RESULTS
  Mean and median followup was 42 and 36 months, respectively. African-American men were significantly more obese than European American men. Mean body mass index was 29.0 in African-American and 28.1 in European American men (p = 0.003). African-American men (OR 2.30, 95% CI 1.04-5.1) were more likely to have higher tumor stage on final pathology. Obesity was a risk factor for biochemical failure in African-American men (adjusted hazard ratio 5.49, 95% CI 2.16-13.9) but not in European American men (HR 1.41, 95% CI 0.96-2.08), and this difference was statistically significant (p value for interaction 0.036).
  
  
  CONCLUSIONS
  Obesity is associated with poorer tumor prognostic characteristics and decreased biochemical relapse-free survival, particularly in African-American men. These data suggest that obesity may in part explain the poorer prostate cancer prognosis seen in African-American men compared to other racial and ethnic groups.
authors.affiliation: Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6021, USA.
authors.forename: E
authors.initials: E
authors.lastname: Spangler
authors.forename: C M
authors.initials: CM
authors.lastname: Zeigler-Johnson
authors.forename: M
authors.initials: M
authors.lastname: Coomes
authors.forename: S B
authors.initials: SB
authors.lastname: Malkowicz
authors.forename: A
authors.initials: A
authors.lastname: Wein
authors.forename: T R
authors.initials: TR
authors.lastname: Rebbeck
mesh_terms: D001741:Black or African American; D015992:Body Mass Index; D018572:Disease-Free Survival; D005060:Europe / Q000208:ethnology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000208:ethnology*; D016017:Odds Ratio; D015995:Prevalence; D011379:Prognosis; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000150:complications / Q000208:ethnology* / Q000628:therapy; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D014481:United States / Q000453:epidemiology