
Hormone Replacement Therapy (HRT) and Breast Cancer: How Concerned Should You be?
You hate the thought of dealing with drenching hot flashes and other uncomfortable symptoms associated with menopause. But even if hormone replacement therapy is a treatment option for you, you should be concerned about its safety, especially after hearing of its link to breast cancer. What are the facts about HRT and breast cancer, and how concerned should you be?
Breast cancer is the most common form of cancer found in women—it is estimated that more than 180,000 women are diagnosed with breast cancer every year. High levels of estrogen have been linked to the development of breast cancer. In older women, the greatest exposure to estrogen is via postmenopausal hormone replacement therapy.
HRT includes the hormones estrogen (estrogen replacement therapy or ERT) and progesterone, or a combination of both. HRT is often used on a short-term basis for the relief of unpleasant menopausal symptoms such as hot flashes, vaginal dryness, and irritability. HRT has been used by postmenopausal women on a long-term basis, with the assumption that it would reduce their risk of osteoporosis and heart disease.
HRT and Incidence of Breast Cancer
A growing body of scientific evidence suggests that HRT, particularly long-term HRT, does increase a woman’s risk of breast cancer.
The July 17, 2002 issue of the Journal of the American Medical Association (JAMA) published results from the Women’s Health Initiative, a randomized trial comparing HRT to a placebo (inactive drug) in 16,608 postmenopausal women. The study, scheduled to run until 2005, was stopped early because researchers found that compared to the placebo group, the women taking combination HRT (estrogen plus progestin) had 26% more invasive breast cancers.
A study of 705 postmenopausal women, published in the February 13, 2002 issue of JAMA, found that the incidence of all types of invasive breast cancer was increased by 60% to 85% in recent long-term users of HRT (defined as greater than four years in the study), whether they took estrogen alone or estrogen plus progestin. According to the study, longer use of HRT and current use of combination HRT were associated with increased risk of lobular breast cancer. Longer-term use of HRT was associated with a 50% increase in nonlobular breast cancer.
Lobular breast cancer is that which starts in cells that make up the lobules at the end of the ducts; ducts and lobules are the structures in the breast where milk is made, stored, and carried through to the nipple for breast-feeding.
According to a 2001 report from the American Cancer Society, a Swedish study, published in the International Journal of Cancer, followed 5,800 women and found an increased incidence of breast cancer, particularly smaller, earlier stage tumors, in postmenopausal women using HRT.
HRT After Breast Cancer
With increasing evidence that HRT is associated with an increased risk of breast cancer, women with a history of breast cancer have been discouraged from using HRT. The belief has been that estrogens might cause a recurrence of breast cancer. However, an observational study published in the May 16 2001 issue of the Journal of the National Cancer Institute found a lower risk of breast cancer recurrence and death in women who used HRT after breast cancer diagnosis compared to women who did not use HRT after breast cancer diagnosis. While more studies are definitely needed, some researchers believe the study results indicate that breast cancer survivors and their physicians can consider oral or vaginal HRT to relieve menopausal symptoms, with less fear that surrounded this option in the past.
What Should Women Do Now?
Researchers with the Women’s Health Initiative and the National Institutes of Health have made the following recommendations regarding the use of HRT:
- For many women, the benefits of short-term HRT may outweigh the risks. Talk to your doctor about your personal risks and benefits.
- If you have been taking HRT, talk to your doctor about whether or not you should continue taking it.
- If you are 50 or older, get screened for breast cancer with mammography every 1 to 2 years. It may be prudent to begin mammography screening in your 40’s, though the benefits of this have not been clearly established.
- Keep up with your regular schedule of breast self-exams.
- Do not take HRT to lower your risk of heart disease and its complications.
- Talk to your doctor about other methods of preventing heart attack, stroke, and osteoporosis. Other medications and lifestyle measures have been shown to reduce the risk of these conditions.
by Amy Scholten, MPH
RESOURCE:
American Cancer Society
SOURCES:
American Cancer Society Website, Hormone replacement therapy linked to lobular breast cancer. Available at: http://www.cancer.org
Accessed February 2003.
Chen C, Weiss N, Newcomb P, et al. Hormone replacement therapy in relation to breast cancer. JAMA. 2002;287:734-741.
O’Meara E, Rossing M, Daling J, et al. Hormone replacement therapy after a diagnosis of breast cancer in relation to recurrence and mortality. Journal of the National Cancer Institute. 2001;93: 754-761.
Li C, Weiss N, Stanford J, et al. Hormone replacement therapy in relation to risk of lobular and ductal breast carcinoma in middle-aged women. Cancer. 2000;88:2570-2577.
Writing Group for the Women’s Health Initiative. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: Principle research from the Women’s Health Initiative Randomized Controlled Trial. JAMA. 2002;288:321-333.
