Bone drug Zometa helps women with early breast cancer

A bone-building drug also may help certain women with early breast cancer, a study shows.

Breast cancer patients who took the drug Zometa, in addition to hormonal therapy, were 35% less likely to relapse than those given placebos, according to a study of 1,800 pre-menopausal women presented Sunday at the annual meeting of the American Society of Clinical Oncology in Chicago.

About 6% of women who took Zometa died or relapsed within five years, compared with 9% of those who did not take the drug, says study co-author Michael Gnant, a surgery professor at the Medical University of Vienna.

Women in the study took a complex combination of medicines that suppress the estrogen that can feed breast tumors. All took a drug called goserelin that makes the ovaries stop producing estrogen.

Doctors then randomly assigned women to receive one of four treatments. Half took an anti-estrogen drug called tamoxifen, which is commonly given after breast cancer surgery, and half received anastrozole, a drug that blocks estrogen's effects and is often prescribed for post-menopausal women. Half of the women who took tamoxifen, along with half the women who took anastrozole, also were given Zometa.

Eric Winer of Boston's Dana-Farber Cancer Institute says it's too soon to know whether the findings will change the standard of care. He notes that researchers have not followed the patients long enough to know whether Zometa helps women live longer and that many doctors may wait to see whether other studies confirm the results.

In this study, women had an average age of 44 and had a low overall risk of relapse. All had undergone surgery and had cancers that respond to hormones, Gnant says. About 98% of patients like these survive five years or more.

Gnant says women taking Zometa, which is commonly used when cancer has spread to the bone, had no serious side effects. Although bisphosphonates are taken to build bone mass, large intravenous doses — bigger than those used in the study — also increase the risk of rot in the jawbone.