title: Long-term use of postmenopausal estrogen and progestin hormone therapies and the risk of endometrial cancer.
abstract: OBJECTIVE
  The purpose of this study was to assess whether endometrial cancer risk among long-term users of (1) sequential estrogen plus progestin 10-24 days per month exceeds that of nonusers and (2) daily estrogen plus progestin (continuous combined hormone therapy) is below that of nonusers.
  
  
  METHODS
  In this population-based case-control study with 1038 endometrial cancer cases diagnosed in 1985-1999 and 1453 control subjects, exclusive users of a single form of hormone therapy were compared with never users of hormone therapy.
  
  
  RESULTS
  For sequential therapy, only long-term use (> or = 6 years) was associated with increased risk (odds ratio, 2.0; 95% CI, 1.2-3.5). Continuous combined therapy was associated with decreased risk (odds ratio, 0.59; 95% CI, 0.40-0.88), with no increased risk among long-term users (odds ratio, 0.77; 95% CI, 0.45-1.3).
  
  
  CONCLUSIONS
  These results support the hypotheses that continuous combined therapy does not increase (and may decrease) endometrial cancer risk and that long-term sequential therapy can lead to a modest increased risk. However, the collective results of all studies of these questions and their clinical implications remain unclear.
authors: Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA. jdoherty@fhcrc.org
authors: Jennifer A
authors: JA
authors: Doherty
authors: Kara L
authors: KL
authors: Cushing-Haugen
authors: Babette S
authors: BS
authors: Saltzman
authors: Lynda F
authors: LF
authors: Voigt
authors: Deirdre A
authors: DA
authors: Hill
authors: Shirley A
authors: SA
authors: Beresford
authors: Chu
authors: C
authors: Chen
authors: Noel S
authors: NS
authors: Weiss
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016889:Endometrial Neoplasms / Q000139:chemically induced*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D011372:Progestins / Q000009:adverse effects*; D012306:Risk
chemical_list: D004967:Estrogens; D011372:Progestins