Estrogen alone is effective for reducing breast cancer risk

December 9, 2010, American Association for Cancer Research

While endogenous estrogen (i.e., estrogen produced by ovaries and by other tissues) does have a well-known carcinogenic impact, hormone replacement therapy (HRT) utilizing estrogen alone (the exogenous estrogen) provides a protective effect in reducing breast cancer risk, according to study results presented at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 8-12.

"Our analysis suggests that, contrary to previous thinking, there is substantial value in bringing HRT with estrogen alone to the guidelines. The data show that for selected women it is not only safe, but potentially beneficial for breast cancer, as well as for many other aspects of women's health," said lead researcher Joseph Ragaz, M.D., medical oncologist and clinical professor in the faculty of medicine, School of Population and Public Health at The University of British Columbia, Vancouver, BC, Canada.

"These findings should intensify new research into its role as a protective agent against breast cancer," he added.

Ragaz and colleagues reviewed and reanalyzed data from the Women's Health Initiative (WHI) trials. WHI is a national health study that focuses on strategies for preventing heart disease, breast and , and fracture in postmenopausal women. The WHI was launched in 1991 and includes more than 161,000 U.S. women aged 50 to 79 years.

"Over the last 30 years HRT has been used almost indiscriminately by women expecting the benefit of reducing cardiac risks, while providing a protective effect against , and improving overall quality of life," said Ragaz. "The WHI results as originally interpreted led to a major pendulum swing against HRT."

The WHI HRT trial consisted of two cohorts of women; the estrogen-alone group of women without a uterus and the estrogen-plus-progestin group of women with a uterus.

Ragaz and colleagues reanalyzed the WHI studies in more detail and found that subsets of women with no strong family history of breast cancer who received estrogen alone had a significantly reduced breast cancer incidence. In addition, the 75 percent of women without benign disease prior to the trial enrollment also had a reduced breast cancer risk.

"Reduction of rates of breast cancer in the majority of women who are candidates for estrogen-based HRT is a new finding because estrogen was always linked with a higher incidence of breast cancer," Ragaz said, "yet estrogen administered exogenously is actually protective for most women."

Based on the results of this current analysis, Ragaz suggested that "while the use of HRT with estrogen alone may reduce the risk of breast cancer and may also be appropriate to manage menopausal symptoms, further research is warranted to elaborate on the optimum treatment regimen, to refine the selection of ideal candidates for estrogen therapy, and to understand the estrogen mechanisms that support the prevention of human ."

"The recommendations based on prior analyses of the results of the WHI HRT studies was not to use HRT, but we are optimistic this will change," he said. "Our conclusion, based on the data presented, should enhance considerations for an early approval of HRT based on estrogen-alone for the majority of selected women suffering with menopausal symptoms and galvanize new research on HRT to define the optimum regimens for individual women."

Related Stories

Recommended for you

Vitamin A derivative selectively kills liver cancer stem cells

April 23, 2018
Acyclic retinoid, an artificial compound derived from vitamin A, has been found to prevent the recurrence of hepatocellular carcinoma (HCC), the most common form of liver cancer. Now, in research published in Proceedings ...

Scientists create better laboratory tools to study cancer's spread

April 23, 2018
Cancer that has spread, or metastasized, from its original site to other tissues and organs in the body is a leading cause of cancer death. Unfortunately, research focused on metastatic disease has been limited by a lack ...

The role of 'extra' DNA in cancer evolution and therapy resistance

April 23, 2018
Glioblastoma (GBM) is the most common and aggressive form of brain cancer. Response to standard-of-care treatment is poor, with a two-year survival rate of only 15 percent. Research is beginning to provide a better understanding ...

Size, structure help poziotinib pose threat to deadly exon 20 lung cancer

April 23, 2018
A drug that failed to effectively strike larger targets in lung cancer hits a bulls-eye on the smaller target presented by a previously untreatable form of the disease, researchers at The University of Texas MD Anderson Cancer ...

How to hijack degrading complexes to put cancer cells asleep

April 23, 2018
Newcastle and Dundee University researchers have uncovered an alternative path of how the breast cancer drug palbociclib drives malignant cells into cell death, senescence.

Single-cell study in a childhood brain tumor affirms the importance of context

April 20, 2018
In defining the cellular context of diffuse midline gliomas, researchers find the cells fueling their growth and suggest a potential approach to treating them: forcing their cells to be more mature.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.