Hutch study to test breast-cancer prevention

Women at higher risk for breast cancer may have a new way to prevent the disease if a treatment being investigated by Fred Hutchinson Cancer Research Center scientists is successful.

Researchers at "The Hutch" will soon begin testing a proven cancer-treatment drug to prevent the disease in postmenopausal women with risks such as being 60 or older or having a family history of breast cancer.

The drug, exemestane, already is used to prevent recurrence of the disease. It prevents the body from producing estrogen, which most breast-cancer tumors need to survive.

"I think it could work. I'm hopeful," said Dr. Anne McTiernan, lead investigator in the Seattle arm of the trial that will involve more than 4,500 women from the United States, Canada and Spain.

Sponsored by the National Cancer Institute of Canada, the ExCel study, as it's called, will last five years and enlist 200 Seattle-area women at increased risk for breast cancer. It will be financed in part by Pfizer, manufacturer of the drug.

McTiernan said as many as 10 percent of women in the U.S. have an increased risk for breast cancer besides being age 60 or older. These include having a family history of the disease, usually in a mother or sister; having one of the two breast-cancer genes; being younger than 12 at first menstrual period; having a first child when older than 30; and having had a benign cyst in the breast.

Information

Fred Hutchinson Cancer Research Center: call 206-667-1391 or visit www.fhcrc.org/phs/excel

If the clinical trial shows that exemestane can prevent the cancer, it will have wide implications for postmenopausal women.

"It really could be quite widely used," McTiernan said. "It definitely could pertain to many, many women."

Previous research has shown that tamoxifen, also used to treat breast cancer, reduced the chance of the disease by 50 percent in women older than 35 at high risk. But many women have been reluctant to use the drug because it also increases the risk of stroke, blood clots in the legs and lungs, uterine cancer and hot flashes.

Exemestane may increase the risk of osteoporosis, and some women have joint and muscle pain or nausea when using the drug, McTiernan said. The study will further assess the impact of these side effects.

The drug, sold under the brand Aromasin, is part of a class of medications called aromatase inhibitors. They prevent the conversion of androgens — male hormones also found in females — into estrogen.

An international study in March 2004 showed that exemestane significantly lengthened survival in breast-cancer patients. And a January 2005 study from the University of Manchester found that another aromatase inhibitor, anastrozole, significantly increased survival and reduced the spread of breast cancer.

Besides testing exemestane, the ExCel study also will examine the impact of exercise on preventing breast cancer, and the drug's effect on quality of life and breast-tissue density, a factor important in being able to read mammograms.

The project originally had been designed to also test the effectiveness of Celebrex in preventing breast cancer in the women. But the well-known drug is part of a class of anti-inflammatory medications, COX-2 inhibitors, that last year was linked to an increased risk of heart attacks and strokes. It was then withdrawn from the trial.

Leaders of the trial say they hope to have initial results of the research within four years.

More than 211,000 women will be diagnosed with breast cancer in 2005 and more than 40,000 will die this year, according to the American Cancer Society.

Warren King: 206-464-2247 or wking@seattletimes.com