Breast Cancer Drug Tamoxifen Helps Heart

Feb. 11, 2005 -- Breast cancer patients taking the drug tamoxifen reap an important fringe benefit -- less heart disease, researchers say.

"Treatment with tamoxifen for women with breast [cancer] also may lower a woman's risk of developing ischemic heart disease (heart attack and chest pain)," say the Boston University scientists, who included Brian Bradbury, DSc, MA.

Breast cancer and heart disease are two of the deadliest conditions a woman can have. More than 2 million women living in the U.S. have been diagnosed and treated for breast cancer, and about 211,000 will be diagnosed with the disease this year, says the American Cancer Society.

Tamoxifen and the Heart

Tamoxifen is the most common drug taken to prevent breast cancer's return. It interferes with the female hormone estrogen, which fuels about two-thirds of breast cancer cell growth.

In postmenopausal women, tamoxifen cuts the risk of breast cancer recurrence by up to 50%, say the researchers. Tamoxifen may also be prescribed to prevent breast cancer in women at high risk for the disease.

Tamoxifen has been found to lower total cholesterol and "bad" LDL levels and other heart disease risk factors, say Bradbury and colleagues.

They tapped a large British medical database to learn more about tamoxifen and heart disease. More than 7,200 women were studied. Those with breast cancer -- about 3,000 women -- were followed while taking tamoxifen; most patients take tamoxifen for five years.

The other women had bladder, colorectal, or nonmelanoma skin cancers, which don't call for tamoxifen. Those women were studied for two to three years, on average.

During the study, 154 women had a heart attack or were treated for chest pain (angina).

Less Heart Disease With Tamoxifen

The breast cancer patients had a 50% reduced risk of heart attack or chest pain, compared with the women with other cancers.

Current use of tamoxifen was associated with a 60% decreased risk of heart disease. Breast cancer patients who used tamoxifen in the past had a 50% reduced risk of heart disease.

Newcomers to tamoxifen also benefited. The study showed a reduce risk of heart disease in even women who received 2-20 prescriptions for the drug. The authors say that it is unlikely that heart-protecting effects from tamoxifen come on so quickly after initiating treatment. However, the study is consistent with prior studies showing tamoxifen's use in women with breast cancer does lower heart disease risk.

The findings appear in the March 15 edition of the journal Cancer.