Estrogen Hormone Therapy Increases Breast Cancer Risk

By Vera Viner

According to a study from the Dana Farber Cancer Institute, long-term use of estrogen hormone therapy increase a woman’s risk of breast cancer.

The researchers followed a set of women, age 30 to 55, for over twenty-five years. It was also found that breast cancer risk increased with the length of estrogen and progesterone use.

“Even though we saw an increased risk in developing breast cancer, we did not see an increased risk for dying from breast cancer,” Wendy Chen, lead author of the study, stated.

This study found that women should avoid long-term use of estrogen alone. Previous studies have shown that estrogen plus progesterone treatment raises breast cancer risk, but this study shows that estrogen by itself raises cancer risk.

Researchers found a 22 percent increase in risk for breast cancer within women who used estrogen hormone therapy for 10 to 14.9 years. Women who used estrogen hormone therapy for 15 to 19.9 years saw a 43 percent increased risk for breast cancer.

This effect did not plateau; the longer a woman used hormone therapy, the higher her cancer risk rose.

“There’s a continued effect over time. The longer you use it, the higher the risk,” said Chen.


“Long-term Use of Estrogen Hormone Therapy Linked to Higher Risk for Breast Cancer.” Medical Xpress. 02 Apr. 2012. Web. 03 Apr. 2012. <>.

“AACR: Study Links Long-Term Estrogen Use to Breast Cancer.” MPR. 02 Apr. 2012. Web. 03 Apr. 2012. <>.


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