Written by Amanda Gardner

Updated on July 16, 2002

TUESDAY, July 16, 2002 (HealthDayNews) -- A combination of chemotherapy and tamoxifen appears to improve some breast cancer patients' survival prospects.

In the largest randomized study of its kind, the benefits of adding chemo ahead of the breast cancer drug were seen in postmenopausal women who had estrogen receptor (ER)-negative cancers -- those that had not spread to the lymph nodes and did not respond to estrogen.

But the researchers, on the other hand, found that postmenopausal women who had (ER)-positive breast cancers did not show any improved outcomes when chemo was given before tamoxifen. ER-positive breast cancers bind to the hormone estrogen, which then fuels the growth of the cancer cells.

"We found that the effectiveness of the chemotherapy was directly related to the hormone responsiveness of the primary tumor," says Richard D. Gelber, director of the statistical and data management center for the International Breast Cancer Study Group (IBCSG), which authored the study. "What the study argues in terms of practice is much greater tailoring of the use of chemotherapy for patients who benefit from it and not for patients in whom endocrine treatments are the key."

This study, which appears in tomorrow's issue of the Journal of the National Cancer Institute, looked at 1,699 postmenopausal women in several different countries, including Switzerland, Slovenia, Australia, New Zealand and Sweden but not the United States. The participants were randomly assigned to one of two groups in a five-year test: the first got three courses of chemo plus tamoxifen and the second got only tamoxifen. The women were further subdivided according to whether their cancer was estrogen receptor-positive or not.

The combination therapy increased the five-year disease-free survival rate in women with ER-negative cancers, from 69 percent to 84 percent. Their overall survival rate went up from 81 percent to 89 percent, compared with the group that took tamoxifen alone.

Postmenopausal women with breast cancers that had not spread to the lymph nodes made up almost half (43 percent) of all women who underwent breast cancer surgery between 1992 and 1996 in the United States.

The results of the new study led the authors to argue that postmenopausal women with lymph-node negative cancer should receive much more individualized treatment regimens, depending at least partially on whether the cancer is estrogen receptor-positive or not.

Other experts are less sanguine about the implications of the study for patients in the United States.

Dr. Bert Petersen, director of the family risk program at Beth Israel Medical Center in New York City, points out that the women in the study received different chemotherapeutic agents than are commonly used in the United States.

"Many of these women wouldn't have been treated this way in this country," he says. "I don't know what the addition of tamoxifen would mean to women in this country. This is not terribly relevant for the way we do things in this country."

What To Do

For more information on tamoxifen, check out the Komen Foundation.

For more on breast cancer therapies, visit the National Institutes of Health.

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