American Association for Cancer Research

Press Releases: 2008

Use of Hormone Supplements Reduces Death from Breast Cancer

December 12, 2008

SAN ANTONIO - While it is true that use of hormone therapy has been shown to increase risk of breast cancer, it also appears that the breast cancer that does develop in these women is less deadly than it might otherwise have been, say California researchers.

At the CTRC-AACR San Antonio Breast Cancer Symposium, researchers said that an analysis of breast cancer deaths in the ongoing 100,000-plus California Teachers Study shows that women who had used hormone replacement were less likely to develop a lethal form of breast cancer, compared with women who didn't use hormones.

Specifically, women who used a combination of estrogen and progestin had a 63 percent reduced relative risk of dying from their cancer, and women who used estrogen reduced their risk by 30 percent, said the study's lead investigator, Sarah Marshall, M.A., an epidemiologist at the University of California, Irvine.

"This may allow women who have used hormones and who are worried about future breast cancer risk, or even their prognosis if they currently have cancer, to breathe a little easier," Marshall said. "Use of these hormones appears to be a benefit in terms of protecting against risk of cancer death."

The researchers theorize that use of hormones may sensitize tumors to the hormones and make them more hormonally-responsive. That could mean that the tumors are diagnosed quicker than they would have been otherwise, and have an improved response to therapy, such as tamoxifen that inhibits estrogen signaling.

Other studies have suggested that hormones can reduce the aggressiveness of breast cancer, but this is the first to take into account the types of breast cancer with which women were diagnosed, as well as estrogen receptor status, tumor grade and stage, and treatment the patients received.

"These results help us predict what is going to happen to women who used hormones and developed breast cancer," Marshall said.

Women participating in the California Teachers Study, a study of teachers and administrators from all over the state conducted by a coalition of academic medical centers, detailed whether they used hormones and for how long. This sub-analysis looked at data from the 2,783 postmenopausal women diagnosed with invasive breast cancer and the 159 women (6 percent) who died of the disease since the study began in 1995.

They concluded that for women who used estrogen-progestin the risk of dying from breast cancer was 63 percent less, and 30 percent less in those who used estrogen, compared with women who did not use hormones. Because women who use hormones tend to be healthier than women who don't - "they are leaner, exercise more, smoke less," said Marshall - the researchers tried to "adjust" for this health advantage, but still found a 45 percent reduced risk of breast cancer death in women who used estrogen and progestin.

"These are very interesting and important findings that may help provide a more complete picture of the relationship between breast cancer and use of hormones in postmenopausal women," she said.

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The mission of the CTRC-AACR San Antonio Breast Cancer Symposium is to produce a unique and comprehensive scientific meeting that encompasses the full spectrum of breast cancer research, facilitating the rapid translation of new knowledge into better care for breast cancer patients. The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio, the American Association for Cancer Research (AACR), and Baylor College of Medicine are joint sponsors of the San Antonio Breast Cancer Symposium. This collaboration utilizes the clinical strengths of the CTRC and Baylor, and the AACR's scientific prestige in basic, translational and clinical cancer research to expedite the delivery of the latest scientific advances into the clinic. The 31st Annual Symposium is expected to draw more than 8,500 participants from more than 80 countries.

Media Contact:
Jeremy Moore
In San Antonio December 10 - 14: