title: The effects of hormone replacement therapy on postmenopausal breast cancer biology and survival.
abstract: BACKGROUND
  The goal of this study was to compare the characteristics of breast cancers and survival rates in HRT users versus nonusers.
  
  
  METHODS
  Data were analyzed for 1055 patients > or = 50 years of age who had definitive therapy for breast cancer from 1994 through 2002.
  
  
  RESULTS
  There were 471 (45%) HRT users. The median age at diagnosis was 61.0 years for HRT users and 68.0 years for HRT nonusers (P < .001). HRT users more often had tumors that were <1 cm (P = .007), node negative (P = .033), and grade I (P = .016). HRT users had a decreased risk of death versus nonusers (hazard ratio = .438, 95% confidence limit = .263 to .729, P = .002).
  
  
  CONCLUSIONS
  HRT users developed breast cancer at a younger age than nonusers; HRT use was associated with the development of biologically more favorable cancers than those that developed in nonusers; and overall and disease-free survival rates were higher in HRT users than nonusers.
authors.affiliation: Department of Surgery and the Center on Outcomes Research and Education, NorthShore University Health System, Evanston, and Northwestern University Feinberg School of Medicine, Chicago, IL, USA. ssener@northshore.org
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Sener
authors.forename: David J
authors.initials: DJ
authors.lastname: Winchester
authors.forename: David P
authors.initials: DP
authors.lastname: Winchester
authors.forename: Hongyan
authors.initials: H
authors.lastname: Du
authors.forename: Ermilo
authors.initials: E
authors.lastname: Barrera
authors.forename: Malcolm
authors.initials: M
authors.lastname: Bilimoria
authors.forename: Seth
authors.initials: S
authors.lastname: Krantz
authors.forename: Sarah
authors.initials: S
authors.lastname: Rabbitt
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000503:physiopathology*; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D016019:Survival Analysis