Hormone replacement therapy, taken to relieve the effects of menopause, is associated with an increased risk for developing breast cancer, but also a decreased risk of dying from breast cancer. What do these seemingly paradoxical findings mean? According to a new report by researchers in New York City, women who develop breast cancer while taking hormone replacement therapy may be more likely to have their cancers detected early as well as have cancer cells that are hormone receptor-positive.
Breast cancer is characterized by the presence of cancer cells in the tissue or ducts of the breast. Depending on the
stage of disease (extent of the cancer at diagnosis), treatment options may include surgery, chemotherapy, radiation therapy, and/or hormone therapy. Often, surgery is followed by radiation therapy to the breast area, chemotherapy, and/or hormone therapy with an agent called
tamoxifen to help prevent a
recurrence (return) of the disease and to improve the chance of survival. Cancer cells that are
hormone receptor-positive, or more sensitive to certain hormones, are often more responsive to the tamoxifen.
Hormone replacement therapy (HRT) is being increasingly used by postmenopausal women to control flushing and hot flashes, prevent osteoporosis, and delay any decline in mental function associated with menopause. Despite reports that long-term use of HRT may increase a woman’s risk for breast cancer, there is also evidence that the death rate from breast cancer is low in women using HRT. Researchers recently evaluated a group of women with breast cancer who used HRT and a group of women with breast cancer who did not use HRT in an attempt to explain these findings.
Researchers at Mount Sinai Medical Center in New York City compared the outcomes of 455 postmenopausal women with breast cancer who did not take HRT with 47 postmenopausal women with breast cancer who did take HRT. The results revealed that those using HRT were younger, more often White, and less obese than those not using HRT. Importantly, those taking HRT more often had their breast cancer detected early and could more often be treated with a less extensive surgery than those not receiving HRT. Five years after treatment for breast cancer, none of the HRT users had a recurrence of the cancer in the breast, while 8% of non-HRT users had a such a recurrence. Seven percent of the HRT users had recurrence of the breast cancer in another site in the body, compared with 10% of non-HRT users.
These researchers were able to confirm that women who develop breast cancer while using HRT have a favorable treatment outcome. These findings suggest that this may be because these women had their cancers detected earlier by mammography and perhaps because their cancer cells are more likely to be hormone receptor-positive, making tamoxifen therapy potentially more effective. Postmenopausal women who are using HRT and are diagnosed with breast cancer may wish to talk with their doctor about the risks and benefits of the HRT as well as the cancer treatment options available. They might also wish to consider talking with their doctor about participating in a clinical trial in which promising new treatments are being studied. Two sources of information on ongoing clinical trials that can be discussed with a doctor include a comprehensive, easy-to-use service provided by the National Cancer Institute (cancer.gov) and the Clinical Trials section and service offered by Cancer Consultants.com (www.411cancer.com). (Obstetrics and Gynecology, Vol 95, No 4, pp 513-518, 2000)
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