Osteoporosis drug may reduce risk of breast cancer

FACTS ABOUT BREAST CANCER

One in nine women will develop the disease sometime during their lifetimes.

Breast cancer is the second-deadliest cancer in women.

Risk factors include increasing age, close relatives with breast cancer and history of noninvasive breast cancer.

The risk for breast cancer increases as we get older.

Women who carry a baby to full term in their early 20s have a lower risk of breast cancer than women who have later first pregnancies or who have no children.

MESSAGE BOARD: Cancer Update

June 15, 1999
Web posted at: 4:03 p.m. EDT (2003 GMT)

(CNN) -- A drug designed to fight osteoporosis may also reduce the risk of breast cancer, according to a study published in this week's Journal of the American Medical Association (JAMA).

Researchers at the University of California at San Francisco (UCSF) set out to look at the ability of the osteoporosis drug raloxifene to protect against bone fractures.

Osteoporosis is a disease of the skeleton caused by an imbalance in the body's bone-rebuilding cycle, resulting in bone loss. It affects nearly 29 million Americans, 80 percent of them women. Menopause is one of the great risk factors for developing osteoporosis. The hormonal changes that occur during menopause can lead to rapid bone loss.

The JAMA study found that after three years on the drug, postmenopausal women had a 76 percent reduction in newly diagnosed invasive breast cancer overall and a 90 percent reduction in estrogen-sensitive breast cancer.

"The most common cause of breast cancer in older women is estrogen-sensitive, or estrogen-receptor positive, breast cancer," said UCSF study leader Dr. Steve Cummings. "Seeing a 90 percent reduction in risk of that kind of cancer is particularly important for older women who are prone to get that kind of cancer."

Raloxifene is not the only drug that has been shown to reduce the risk of breast cancer. A year ago, researchers announced tamoxifen lowers the chances of breast cancer in healthy women by almost half.

So which drug is better, raloxifene or tamoxifen?

On paper, raloxifene's ability to reduce breast cancer by 76 percent may look better, but researchers warn women should not be misled.

Unlike the tamoxifen study, the raloxifene study was designed to study osteoporosis, not breast cancer.

"It's comparing apples and oranges; it's really not the same," said Dr. Janice Gallishaw of St. Joseph's Hospital of Atlanta. "You have to study the impact of raloxifene in a trial that is designed to answer the question: Does it prevent breast cancer in women at high risk of getting breast cancer?"

According to Gallishaw, a woman's family history and whether she has had any biopsies need to be considered in any study of raloxifene's effectiveness in reducing risk of breast cancer.

Women who are at high risk for breast cancer will be participating in a just-announced study comparing the two drugs. Learning more about the risks and side effects and who can benefit from raloxifene and tamoxifen will help all women at high risk of breast cancer.