Estrogen Therapy Protects Most Women from Breast Cancer

Kathleen Blanchard's picture

Contrary to previous thinking, researchers now say estrogen hormone replacement therapy, used alone, protects a majority of women from breast cancer. Researchers from the School of Population and Public Health at The University of British Columbia, Vancouver, BC, Canada say women without a strong family history of breast cancer gained "significant" protection from the disease with estrogen HRT.

Women with Menopausal Symptoms should be Considered for Estrogen Therapy

Researchers conducted a re-analysis of findings from the Women's Health Initiative (WHI) hormone replacement therapy trials that started in 1991 and included 161,000 U.S. women aged 50 to 79 years. They concluded the findings, “…should enhance considerations for an early approval of HRT based on estrogen-alone for the majority of selected women suffering with menopausal symptoms..."

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 and colleagues also found that 75 percent of women without benign breast disease were protected from cancer. The study included women without a uterus receiving just estrogen and another group of women with uteri intact, given estrogen and progestin therapy.


"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 bone fracture, and improving overall quality of life," said Ragaz. "The WHI results as originally interpreted led to a major pendulum swing against HRT."

He says estrogen may be appropriate for treatment of menopausal symptoms, and "while the use of HRT with estrogen alone may reduce the risk of breast cancer", more studies are needed to determine optimal dosing, who will benefit most and the protective mechanism of estrogen against breast cancer.

The re-analysis of the Women's Heart Initiative changes thinking that estrogen promotes breast cancer. For a large number of women, the researchers say using estrogen alone has a protective effect. More studies are needed to pinpoint the best candidates, HRT dosing, and exactly how estrogen works to thwart breast cancer.