As reported by The Hartford Courant, April 18, 2006.

Drug Cuts Cancer Risk

Reduces Breast Tumors with Fewer Side Effects

By William Hathaway

The osteoporosis drug raloxifene offers women at high risk of breast cancer as much protection against developing the disease as tamoxifen, the current standard of cancer prevention care, according to a study released Monday.

The Study of Tamoxifen and Raloxifene, or STAR trial, tracked health outcomes for more than 20,000 postmenopausal women and was one of the largest breast cancer prevention trials ever undertaken. Researchers found that women who took raloxifene, sold under the brand name Evista, were also at lower risk of contracting uterine cancers or blood clots, two rare side effects of tamoxifen.

"It's very exciting because this gives women who are at increased risk of breast cancer another tool to decrease their risk of disease," said Dr. Kristen Zarfos, director of the Comprehensive Breast Health Center at St. Francis Hospital and Medical Center in Hartford.

However, premenopausal women who are at risk for breast cancer may not receive the same benefits from raloxifene, cautioned Dr. Patricia DeFusco, principal investigator at Hartford Hospital for the National Surgical Adjuvant Breast and Bowel Project, the consortium of cancer professionals who conducted the STAR trial.

Tamoxifen should continue to be prescribed to women who are still menstruating, she said.

"Not every woman should run out and get on this medicine," DeFusco said, referring to raloxifene.

Researchers noted during previous osteoporosis trials that raloxifene seemed to decrease the risk of breast cancer. The STAR trial was designed to investigate whether the drug was as effective in preventing breast cancer as tamoxifen, a drug that cuts the risk of developing breast cancer in half, but which in rare cases causes endometrial cancer or blood clots.

"We didn't know if we'd see the benefits in a trial of women at high risk," said Dr. Carolyn Runowicz, director of the Carole and Ray Neag Comprehensive Cancer Center at the University of Connecticut Health Center and president of the American Cancer Society. "And in fact, it does hold out."

The women enrolled in the study had to be postmenopausal and considered at high risk for the disease - primarily because they had a family history of breast cancer or had an abnormal biopsy.

After following the women's health for four years, researchers found the two medications offered almost exactly the same protection against developing breast cancer. Of the 9,726 women in the tamoxifen group, 163 developed invasive breast cancer. In the raloxifene group, 167 of 9,726 developed cancer.

Women in the study who took raloxifene were less likely to develop uterine cancer and blood clots than women taking tamoxifen - side effects that have hampered the widespread use of tamoxifen.

Of 4,712 women who had a uterus and took raloxifene, 23 developed uterine cancer, compared with 36 of the 4,732 women who still had a uterus and took tamoxifen. Additionally, 99 in the raloxifene group developed either blood clots or pulmonary embolisms, compared with 141 taking tamoxifen.

However, there was no statistical difference between rates of strokes, heart attacks and bone fractures in the two groups.

Women who received tamoxifen had fewer non-invasive breast cancers than those who took raloxifene.

"We don't know what that means," DeFusco said. "It needs further study."

In practice, women who are at risk of both bone disease and breast cancer will be more likely to be given raloxifene, Zarfos and DeFusco predicted.

"In all honesty, the risks [of tamoxifen] are small, but they are real," DeFusco said.

Women who are not at risk for either osteoporosis or breast cancer do not need the drug, she said.