Authors' objectives:

To evaluate and update the prior review evaluating the risk of breast cancer and breast cancer (BCA) death associated with the use of postmenopausal hormone replacement therapy (HRT) by reviewing the medical literature which has been published since the last US Preventive Services Task Force update.

Authors' results and conclusions: For ever or short-term use of estrogen, 7 of the 8 meta-analyses, 8 of the 11 case-control studies, and 6 of the 7 cohort studies evaluating incidence showed no increase in breast cancer with hormone replacement therapy. Of the original studies reviewed evaluating incidence, 12 of 19 showed no increased risk of breast cancer with long duration ERT or HRT use. However, 5 of the meta-analyses showed increased risk with duration over 5 years and 2 important cohort studies showed increased risk with longer duration use. Eleven original studies evaluated combined estrogen and progestin, and one showed increased risk of BCA with short-term use; 3 of the 5 evaluating duration with combined therapy showed increased risk that was statistically significant. Current use of ERT was associated with significantly increased risk of breast cancer in two of the best cohort studies; use of combined therapy was associated with increased risk in 3 studies. Six recent cohort studies (1992-2000) evaluated breast cancer mortality in association with hormone use: 1 showed increased risk of death, 4 showed decreased risk of death, and one showed no association. Several recent studies show that post-menopausal estrogen therapy is associated with increased breast density by mammography and that adding progesterone to estrogen results in even greater increases in breast density. Finally, there is evidence suggesting an important interaction between HRT and alcohol use and HRT and lower body weight.

Authors' recommendations: The association of short-term hormone replacement therapy with the development of breast cancer is uncertain based on multiple studies with inconsistent findings. Among studies indicating increased risk, the risk is largely confined to current and long-term use (>5-10 years), and the risk is relatively small (RR 1.2-1.5). Reduced mortality is a fairly consistent finding among the studies evaluating breast cancer mortality and HRT use. The addition of progesterone to estrogen and current, as well as long-term, use may be associated with breast cancer risk above that of estrogen itself. Although the biological plausibility of an association between postmenopausal hormone use and breast cancer is high, the studies showing risk or benefit from the use of post-menopausal hormones are limited by the observational nature of the epidemiologic data existing to date. Data from randomized controlled trials are needed to validly evaluate the relationship.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/uspstf/uspspmho.htm

Year Published: 2002

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)