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Is Hormone Therapy Safe for Breast Cancer Survivors?

WebMD Health News

Aug. 21, 2001 -- Women continue to get mixed messages about the good and the bad sides of hormone replacement therapy, commonly used to treat hot flashes and other symptoms of menopause. But a recent study shows that hormone therapy -- traditionally thought of as taboo for breast cancer survivors -- is not only safe but may even help prevent the cancer from coming back.

The study, from the May 16 Journal of the National Cancer Institute, shows that breast cancer survivors treated with hormone replacement therapy, commonly called HRT, had about half the risk of cancer recurrence and one-third the risk of dying from breast cancer than women not treated with HRT.

"This is certainly not a definitive study," researcher Ellen S. O'Meara, PhD, tells WebMD. "And we are not saying hormone therapy is right for all women who have had breast cancer, or even all of those with menopausal symptoms. But these data suggest there is a reason to consider HRT, or at least not to rule it out automatically."

O'Meara is a researcher at Seattle's Fred Hutchinson Cancer Research Center.

HRT, involving either estrogen alone or estrogen and progestin, is widely used by women to help reduce hot flashes, depression, and other symptoms associated with menopause. Because estrogens are involved in the development of initial breast cancers, and hormone therapy in women with no history of the disease is believed to increase the chance of getting breast cancer, most doctors don't recommend it for their breast cancer patients.

In this study, O'Meara and colleagues studied 174 HRT-treated women diagnosed with breast cancer in the past and compared them with similar breast cancer survivors who had not used HRT.

The hormone users stayed on the drug for an average of 15 months, and both groups of women were followed for about four years. The researchers noted a significant decrease in the risk of breast cancer recurrence and death in hormone users, but they say it is still not clear from this relatively small study if HRT is actually beneficial in breast cancer patients.

They noted that the risk of breast cancer developing in the previously unaffected breast was higher among HRT users than nonusers.

"The idea that this therapy would actually be beneficial to breast cancer patients, in the sense that it lowers recurrence, is completely contrary to our understanding of breast cancer and how it grows," Jack Cuzick, PhD, of the Imperial Cancer Research Fund in London, tells WebMD. "Everything we know suggests this treatment couldn't really be beneficial. But in fact, the ... evidence [from this study] does suggest this is a real possibility. And we have been fooled before."

Cuzick, who wrote an editorial accompanying O'Meara's study, says even if HRT turns out to have no effect on the prognosis of breast cancer, it could be a great benefit for survivors with menopausal symptoms. The findings from this study give "added support and urgency" to trials of HRT in menopausal women with breast cancer that are now under way in Sweden and the U.K., he adds.

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