Evista for Breast Cancer Prevention

Medically Reviewed by Melinda Ratini, MS, DO on March 02, 2024
Written by Debra Fulghum Bruce, PhD
4 min read

Evista, also called raloxifene, is a medication that's used to reduce the risk of invasive breast cancer in post-menopausal women. It's also used to reduce the risk of spinal fractures related to osteoporosis. It was during studies of the use of Evista to treat osteoporosis that researchers noticed that among post-menopausal women who took the drug there was a lower rate of invasive breast cancer. After additional studies, the FDA approved the use of Evista for the prevention of breast cancer.

Evista is a selective estrogen receptor modulator, or SERM. SERMs have anti-estrogen effects on some tissues and estrogen-like effects on other tissues. They are used to reduce the risk of invasive breast cancer in post-menopausal women who are at a high risk of developing breast cancer. However, it should not be given to women who have already had breast cancer nor should it be used in the treatment of breast cancer.

One out of every four cancer diagnoses in women each year is invasive breast cancer. It can be deadly if not caught and treated early.

Noninvasive breast cancer remains in the milk ducts or lobules -- lobes -- of the breast. It does not spread to the surrounding tissue. Invasive breast cancer, though, spreads outward from the milk ducts and lobules into the surrounding breast tissue. Eventually, it spreads to other areas of the body.

Evista prevents invasive breast cancer in post-menopausal women who are at high risk. Evista is the second drug to be approved by the FDA to prevent invasive forms of breast cancer. The first drug, tamoxifen, has been on the market for several decades.

Evista works by blocking estrogen in the breast tissue of women at high risk. The medication helps prevent the spread of tumors that require estrogen to grow.

Evista is not effective, however, in women who currently have invasive breast cancer or who have had invasive breast cancer. It won't prevent cancer in these women, nor will it treat cancer once it appears.

Although Evista can reduce the likelihood of invasive breast cancer, it's important to be aware of its serious side effects. Those serious side effects include:

Other milder side effects include:

Experts caution that some women who take Evista will still get invasive breast cancer. So women need to consider the pros and cons of taking a medication with very serious side effects.

Breast cancer is more commonly found in women over age 60. So women who are over 60 may benefit the most from Evista. Also, if you are a woman who has a family history of breast cancer or who has a genetic predisposition, you may benefit. Other factors that can increase your risk of developing invasive breast cancer include a previous lobular carcinoma in situ (a premalignant condition) diagnosis, a history of frequent breast biopsies, having your first child at a later age, or starting your periods at a later age. Your doctor can help identify your own risk for breast cancer.

The FDA advises that women with the following conditions not take Evista:

  • Women who are pregnant or planning to become pregnant
  • Women with present or past blood clots in the eyes, lungs, or legs
  • Women taking cholestyramine, a cholesterol-lowering drug
  • Women taking supplemental estrogen
  • Women who are pre-menopausal

Evista and tamoxifen, another SERM, have similar results and side effects in preventing invasive breast cancer, although Evista had less uterine cancers involved with its use.

Several studies have investigated the effects of Evista and tamoxifen in more than 37,0000 women. For instance, one study that involved more than 19,000 women at high risk of developing breast cancer found that both medications had similar results in reducing invasive breast cancer. Unlike tamoxifen, however, Evista was not shown to reduce noninvasive forms of breast cancer. Noninvasive forms include ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS).

Both Evista and tamoxifen may increase the risk of developing blood clots and strokes. Some findings suggest that Evista might be less likely to cause clots, pulmonary embolisms, and strokes than tamoxifen. But other studies say there is no difference. Both raloxifene and tamoxifen carry risks. Because of the possible side effects, you and your doctor should cautiously weigh the benefits and risks of using either drug to prevent invasive breast cancer.