title: Prognostic characteristics of breast cancer among postmenopausal hormone users in a screened population.
abstract: OBJECTIVE
  We determined the risk of breast cancer and tumor characteristics among current postmenopausal hormone therapy users compared with nonusers, by duration of use.
  
  
  METHODS
  From January 1996 to December 2000, data were collected prospectively on 374,465 postmenopausal women aged 50 to 79 years who underwent screening mammography. We calculated the relative risk (RR) of breast cancer (invasive or ductal carcinoma-in-situ) and type of breast cancer within 12 months of postmenopausal therapy use among current hormone users with a uterus (proxy for estrogen and progestin use) and without a uterus (proxy for estrogen use), compared with nonusers.
  
  
  RESULTS
  Compared with nonusers, women using estrogen and progestin for >/= 5 years were at increased risk of breast tumors of stage 0 or I (RR, 1.51; 95% CI, 1.37 to 1.66), stage II or higher (RR, 1.46; 95% CI, 1.30 to 1.63), size </= 20 mm (RR, 1.59; 95% CI, 1.43 to 1.76), size greater than 20 mm (RR, 1.24; 95% CI, 1.09 to 1.42), grade 1 or 2 (RR, 1.60; 95% CI, 1.44 to 1.77), grade 3 or 4 (RR, 1.54; 95% CI, 1.37 to 1.73), and estrogen receptor-positive (RR, 1.72; 95% CI, 1.55 to 1.90). Estrogen-only users were slightly more likely to have estrogen receptor-positive breast cancer compared with nonusers (RR, 1.14; 95% CI, 1.06 to 1.23).
  
  
  CONCLUSIONS
  Use of estrogen and progestin postmenopausal hormone therapy for five years or more increased the likelihood of developing breast cancer, including both tumors with favorable prognostic features and tumors with unfavorable prognostic features.
authors.affiliation: San Francisco Veterans Affairs Medical Center, General Internal Medicine Section, 111A1, 4150 Clement St, San Francisco, CA 94121, USA. kerliko@itsa.ucsf.edu
authors.forename: Karla
authors.initials: K
authors.lastname: Kerlikowske
authors.forename: Diana L
authors.initials: DL
authors.lastname: Miglioretti
authors.forename: Rachel
authors.initials: R
authors.lastname: Ballard-Barbash
authors.forename: Donald L
authors.initials: DL
authors.lastname: Weaver
authors.forename: Diana S M
authors.initials: DS
authors.lastname: Buist
authors.forename: William E
authors.initials: WE
authors.lastname: Barlow
authors.forename: Gary
authors.initials: G
authors.lastname: Cutter
authors.forename: Berta M
authors.initials: BM
authors.lastname: Geller
authors.forename: Bonnie
authors.initials: B
authors.lastname: Yankaskas
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Taplin
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Carney
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000453:epidemiology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000453:epidemiology; D004338:Drug Combinations; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D017698:Postmenopause / Q000187:drug effects*; D011372:Progestins / Q000009:adverse effects*; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
chemical_list: D004338:Drug Combinations; D004967:Estrogens; D011372:Progestins