HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Conjugated equine estrogens and breast cancer risk in the Women's Health Initiative clinical trial and observational study.

Abstract
The Women's Health Initiative randomized controlled trial found a trend (p = 0.09) toward a lower breast cancer risk among women assigned to daily 0.625-mg conjugated equine estrogens (CEEs) compared with placebo, in contrast to an observational literature that mostly reports a moderate increase in risk with estrogen-alone preparations. In 1993-2004 at 40 US clinical centers, breast cancer hazard ratio estimates for this CEE regimen were compared between the Women's Health Initiative clinical trial and observational study toward understanding this apparent discrepancy and refining hazard ratio estimates. After control for prior use of postmenopausal hormone therapy and for confounding factors, CEE hazard ratio estimates were higher from the observational study compared with the clinical trial by 43% (p = 0.12). However, after additional control for time from menopause to first use of postmenopausal hormone therapy, the hazard ratios agreed closely between the two cohorts (p = 0.82). For women who begin use soon after menopause, combined analyses of clinical trial and observational study data do not provide clear evidence of either an overall reduction or an increase in breast cancer risk with CEEs, although hazard ratios appeared to be relatively higher among women having certain breast cancer risk factors or a low body mass index.
AuthorsRoss L Prentice, Rowan T Chlebowski, Marcia L Stefanick, Joann E Manson, Robert D Langer, Mary Pettinger, Susan L Hendrix, F Allan Hubbell, Charles Kooperberg, Lewis H Kuller, Dorothy S Lane, Anne McTiernan, Mary Jo O'Sullivan, Jacques E Rossouw, Garnet L Anderson
JournalAmerican journal of epidemiology (Am J Epidemiol) Vol. 167 Issue 12 Pg. 1407-15 (Jun 15 2008) ISSN: 1476-6256 [Electronic] United States
PMID18448442 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural)
Chemical References
  • Estrogens
  • Estrogens, Conjugated (USP)
Topics
  • Aged
  • Breast Neoplasms (chemically induced, epidemiology)
  • Estrogen Replacement Therapy (adverse effects)
  • Estrogens (adverse effects)
  • Estrogens, Conjugated (USP) (adverse effects)
  • Female
  • Humans
  • Incidence
  • Middle Aged
  • Odds Ratio
  • Randomized Controlled Trials as Topic
  • Risk Assessment
  • Risk Factors
  • Surveys and Questionnaires
  • United States (epidemiology)
  • Women's Health

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: