Women Who Take An Estrogen Suppressing Drug For Up To 15 Years Could Reduce Breast Cancer Recurrence, Study Shows

A study published in June 2016 states women who take a certain type of hormonal drug for up to 15 years may reduce the recurrence of breast cancer later in life.

Chances of recurrence of breast cancer are already low, but doctors may suggest a longer drug therapy started during the early stages of breast cancer may prevent the disease from returning in postmenopausal women.

Study Statistics

The study examined 1,918 postmenopausal women split into two groups. One group was given a special class of drugs known as aromatase inhibitors, which suppress estrogen. The other group was given a placebo. Women in the group that took the inhibitors for 10 years lowered their chances of recurring breast cancer by 34 percent; many of these women had already been on aromatase inhibitors for five years when the study started.

By the end of the study’s time period, 95 percent of the women who took the inhibitors were cancer-free versus 91 percent of those who didn’t take the drugs. A total of 67 women, or 7 percent of the control group, saw a recurrence of breast cancer after taking letrozole for five years, while 10.2 percent of women who took a placebo, or 98 women, had a recurrence of breast cancer.

Woman holding a glass of water and pills, detail

Why Inhibitors Are Important

Aromatase inhibitors are important in this case because they lowered the recurrence of breast cancer in some cases. The risks of the cancer coming back are already small because more than 90 percent of women who had breast cancer initially remained cancer-free. However, this study brings hope to millions of women all over the world who may fear a relapse of breast cancer, because aromatase inhibitors are readily available. As much as 80 percent of breast cancers come from the hormone estrogen, and aromatase inhibitors suppress estrogen in the body.


Article continues below

Our Featured Programs

See how we’re making a difference for People, Pets, and the Planet and how you can get involved!


Dr. Eric Winer, director of the breast cancer program at Boston’s Dana-Farber Cancer Institute, says taking these drugs for longer periods of time is one option for some women, but not for everyone. Taking these drugs may lead to vaginal dryness, hot flashes and loss of libido. More serious side effects include bone loss and osteoporosis. Taking estrogen-suppressing drugs is nothing new, but taking them for longer represents a possibility of lowering the return of breast cancer for some women.

Provide Mammograms

Support those fighting Breast Cancer at The Breast Cancer Site for free!