Elsevier

Obstetrics & Gynecology

Volume 98, Issue 3, September 2001, Pages 498-508
Obstetrics & Gynecology

Review
Hormone replacement therapy and breast cancer: a qualitative review1,

https://doi.org/10.1016/S0029-7844(01)01453-3Get rights and content

Abstract

OBJECTIVE:

To assess whether recent epidemiologic evidence supports an association between use of estrogen replacement therapy or hormone replacement therapy and risk of breast cancer.

DATA SOURCES:

The keywords “estrogen,” “estrogen replacement therapy,” or “hormone replacement therapy,” and “breast cancer” or “breast neoplasm,” were used to search for articles published from 1975–2000 in MEDLINE and Dialogweb. Only articles published in peer-reviewed journals and containing original data were included in this review.

METHODS:

Unadjusted or age-adjusted risk estimates for breast cancer among ever users of estrogen therapy compared with never users were abstracted from published articles or calculated using the data provided in the published reports.

TABULATION, INTEGRATION, AND RESULTS:

We found little consistency among studies that estimated the risk of breast cancer in hormone users compared with nonusers and in studies assessing the risk by duration of use. However, there was consistently a lower risk of death from breast cancer in hormone users compared with nonusers.

CONCLUSION:

The evidence did not support the hypotheses that estrogen use increases the risk of breast cancer and that combined hormone therapy increases the risk more than estrogen only. Additional observational studies are unlikely to alter this conclusion. Although a small increase in breast cancer risk with hormone therapy or an increased risk with long duration of use (15 years or more) cannot be ruled out, the likelihood of this must be small, given the large number of studies conducted to date.

Section snippets

Methods

We identified a list of publications of observational epidemiologic studies that included original data on ERT and breast cancer risk, HRT and breast cancer risk, and hormone therapy and breast cancer mortality.

Data sources

The keywords “estrogen,” “estrogen replacement therapy” or “hormone replacement therapy,” and “breast cancer” or “breast neoplasm,” were used to search for articles published from 1975–2000 in MEDLINE and Dialogweb. Each coauthor performed searches using several combination terms, such as “estrogen plus breast cancer and/or breast neoplasm,” “estrogen replacement therapy plus breast cancer and/or breast neoplasm,” “hormone replacement therapy plus breast cancer and/or breast neoplasm.”

Results

We identified 45 publications that assessed the association between ERT and breast cancer risk (Figure 1). 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65 Twenty studies assessed the association between HRT and breast cancer risk (Figure 2), 31, 40, 44, 45, 47, 51, 53, 54, 55, 56, 57, 60, 61, 63, 64, 65, 66, 67, 68, 69 five assessed the risk of hormone therapy and

Conclusion

Over 25 years ago, epidemiologic studies showed that ERT was associated with an increased risk of endometrial cancer, and that association was consistent among studies, relatively strong, and increased with increasing duration of use. In contrast, the relatively large body of literature on the association between estrogen and breast cancer is inconsistent, and the distribution of risk estimates is what would be expected if there were no association. That is, most of the estimates of risk

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  • Cited by (0)

    This work was supported by grants from the Department of Defense (# DAMD 17-00-0321 to Trudy Bush and Jodi Flaws) and Wyeth-Ayerst Laboratories (Trudy Bush).

    Dr. Bush received honoraria from Wyeth-Ayerst Laboratories for speaking on this topic.

    1

    We thank Karen Mittleman, Laura Hirshfield, and Lynn Van Ruiten for their assistance.

    2

    Dr. Bush is deceased (March 14, 2001).

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