Bone Drug Prevents Breast Cancer Return
Zometa May Lower Relapse Rate for Early-Stage Breast Cancer Patients
May 31, 2008 (Chicago) -- A potent bone-building drug may cut the risk of relapse in premenopausal women with early breast cancer, a study shows.
In a study of more than 1,800 patients, women who got two injections a year of the bone drug Zometa were about one-third less likely to suffer a recurrence than those who did not.
"Zometa creates a tumor-hostile environment that helps to keep cancer away, and it is very safe," says researcher Michael Gnant, MD, professor of surgery at the Medical University of Vienna, Austria.
"This offers a new option for premenopausal women with early-stage breast cancer," many of whom have traditionally been treated with toxic chemotherapy drugs, he tells WebMD.
Gnant presented the findings at the annual meeting of American Society of Clinical Oncology (ASCO).
Zometa's Antitumor Effects
Zometa is a member of a class of drugs called bisphosphonates, which reduce the risk of fractures in cancers that spread to the bone. Drugs in the bisphosphonate class are also used to treat osteoporosis.
Lab and animal studies suggest that Zometa might also have a range of antitumor effects, Gnant says. The research suggests it can inhibit cell growth, reduce cells' ability to stick to one another, cut off the growth of blood vessels that feed tumors, and stimulate cancer-fighting immune cells.
The new study, conducted by the Austrian Breast & Colorectal Cancer Study Group, involved 1,801 younger women who hadn't gone through menopause and had early breast cancer that was fueled by hormones.
All the women underwent surgery to remove their breast tumor and were given a drug that halts the production of estrogen, thus inducing menopause.
The women were then randomly assigned to standard hormone treatment with either tamoxifen or Arimidex. Tamoxifen is an anti-estrogen that works against estrogen's effect on cells, while Arimidex actually shuts down the body's ability to make estrogen. Both drugs have been shown to help prevent recurrences after surgery for early-stage breast cancer.
Half the women in each group were also given Zometa. The rest got a placebo. They were treated for three years.
Five years later, the risk of relapse was 36% lower in women taking either hormone therapy plus Zometa, compared with hormone therapy alone.
Overall, cancer came back in 6% of women who received Zometa vs. 9% who got the placebo.
There were no differences in the results between women taking tamoxifen and those taking Arimidex.
Zometa was well tolerated, and none of the women developed kidney damage or jaw bone death, two side effects that have been linked to bisphosphonate drugs.
The trial was funded in part by Novartis, which makes Zometa.
Julie Gralow, MD, chairwoman of ASCO's communications committee and a breast cancer specialist at the University of Washington, says that "the findings will change practice."