Bone drug staves off breast cancer

Nationwide study finds osteoporosis treatment as effective as tamoxifen with fewer side effects

April 18, 2006|By JONATHAN BOR | JONATHAN BOR,SUN REPORTER

Women at high risk for breast cancer might have a safer option for preventing the disease, doctors said yesterday after concluding one of the largest breast cancer prevention trials in history.

A nationwide trial among more than 19,000 post-menopausal women showed that a popular drug used to prevent and treat osteoporosis is just as effective in staving off breast cancer as the older standby, tamoxifen, but with fewer side effects.

Both medications cut in half a woman's chance of developing breast cancer, but women taking the osteoporosis drug - called raloxifene and sold as Evista - developed fewer uterine cancers and blood clots. They also suffered fewer hot flashes, night sweats and other unpleasant symptoms.

"This is good news for women," said Dr. Leslie Ford, associate director for clinical research at the National Cancer Institute. "We think this gives women a real choice."

"It's clear that we feel that raloxifene is the winner in this trial," said Dr. D. Lawrence Wickerham, associate chairman of a nationwide consortium that organized the trial. "Already, a half-million or more women are on raloxifene for treatment or prevention of osteoporosis. It's likely this will allow for expansion of that population."

For now, only tamoxifen has government approval as a preventive measure against breast cancer, although researchers said yesterday that they expect Eli Lilly, which makes raloxifene, to seek permission.

Legally, however, doctors can prescribe drugs approved for one condition to treat another.

An estimated 9 million women in the United States are post-menopausal and at increased risk for breast cancer.

In 1998, a landmark trial demonstrated tamoxifen's powerful effect in preventing breast cancer in high-risk patients. But women have generally avoided taking it for that purpose because it was associated with a higher risk of uterine cancer and blood clots of major veins or the lung. Both are potentially life-threatening.

Researchers turned their attention to raloxifene after an osteoporosis trial produced evidence that women who took the drug also had a lower incidence of breast cancer than those taking the placebo.

Osteoporosis is a bone-thinning disease common in post-menopausal women.

In 1999, doctors at 300 hospitals across the country began recruiting patients for a trial pitting tamoxifen against raloxifene.

To qualify, women had to be post-menopausal, at least 35 years old and have a history of benign breast disease, a family history of breast cancer or other factors that could place them at increased risk.

Volunteers were randomly assigned to receive either raloxifene, Lilly's Evista, or tamoxifen, which is marketed by AstraZeneca as Nolvadex but also available in generic form.

The trial was run by a Pittsburgh-based consortium called the National Surgical Adjuvant Breast and Bowel Project, which has produced several landmark studies over the past 40 years. Among them was a trial that established lumpectomy plus radiation as the standard surgical treatment for breast cancer.

Doctors participating in the most recent trial called it an important step, though not the last, in finding an effective and relatively safe drug to prevent a disease that claims 40,000 lives a year.

"For those people who are at high risk for cancer, this study is another ray of hope because it did reduce the risk of breast cancer by 50 percent," said Dr. Barry Meisenberg, head of hematology and oncology at the University of Maryland's Greenebaum Cancer Center.

Because it had fewer side effects, Meisenberg said, raloxifene will probably become the drug of choice for post-menopausal women hoping to prevent the disease.

One national drug chain charges $90 for a month's supply of taxmoxifen, and $117 for a similar amount of raloxifene.

Dr. John Zapas, a surgical oncologist at Franklin Square Hospital Center, said the trial "showed that there's an equivalent drug out there with less side effects and a lower incidence of uterine cancer."

Zapas said he still considers tamoxifen the first option for most women because of its longer track record. But he said raloxifene is a good choice for women who might be at higher risk for one of the conditions associated with tamoxifen:

"Obviously, if a woman says she's had a deep vein thrombosis [blood clot] before, I wouldn't hesitate to recommend the other."

Said Dr. Kala Visvanathan, an oncologist at the Johns Hopkins Kimmel Cancer Center: "It enables us to offer women at increased risk of breast cancer a second drug which has been equally efficacious in reducing the incidence of breast cancer, and the side effect profile seems very promising."

Both drugs work by blocking the female hormone, estrogen, in breast tissues.

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