Hormone replacement therapy

The Canadian Cancer Society recommends that women avoid taking HRT for any reason other than to relieve severe menopausal symptoms that have not responded to other treatment.

If you are thinking about taking HRT, your decision should be made with your doctor based on the risks and benefits associated with taking it. These include:

• how severe your menopausal symptoms are
• your individual and family history of heart disease, breast and ovarian cancer, osteoporosis and dementia
• how long you will be taking HRT

If you and your doctor decide that taking HRT is right for you, the lowest effective dose should be used for the shortest period of time possible to control the menopausal symptoms for which it was started in the first place.

During menopause there are changes in a woman’s hormones. These changes can cause symptoms such as hot flashes, sleep disturbances and mood swings. Some women take hormone replacement therapy to relieve these symptoms.

Hormone replacement therapy can be taken as a combination of estrogen plus progestin (combined HRT) or as estrogen only. Combined HRT is used because taking estrogen alone can cause cancer of the uterus. Women who have had their uterus and ovaries removed surgically no longer face the risk of uterine cancer and may take estrogen alone.

Although combined HRT may help to relieve menopausal symptoms, protect against osteoporosis (thinning of the bones) and reduce risk of colon cancer, research shows that long-term use of combined HRT also increases the risk of breast cancer, ovarian cancer, heart disease, stroke and pulmonary embolism (blood clots in the lung). The research suggests that the risks of long-term combined HRT use outweigh the benefits for most women.

Women’s Health Initiative study
In 2002, a large study in the United States called the Women’s Health Initiative found a 25% increase in breast cancer risk among the more than 16,600 women aged 50–79 who were taking combined HRT during the study.

Regular use of HRT also appeared to increase the risk of heart disease, stroke and pulmonary embolism (blood clots in the lungs) but decreased risk of colorectal cancer and hip fractures.

Women taking combined HRT were also found to be more likely to require endometrial biopsies, require follow-up testing for vaginal bleeding, and were more likely to have abnormal mammograms.

In 2008, follow-up results to the WHI study were published, which showed that women continued to have an increase in overall cancer risk even after 3 years of stopping use of HRT. The researchers concluded that the health risks continue to exceed the health benefits.

In 2009, an updated analysis of the WHI data further supported the association between HRT use and elevated breast cancer risk by showing that changes in mammography rates could not explain the drop in breast cancers that occurred after many women in the study stopped using HRT. This finding confirmed similar observations in other countries.

In a separate arm of the study which looked at the use of estrogen-only therapy among women who had a hysterectomy, the researchers found an increased risk of stroke, a decreased risk of hip fractures, and a slightly decreased risk of breast cancer.

Risk of ovarian cancer
A population-based study of nearly 1 million post-menopausal women in Denmark aged 50 to 79 years showed that the risk of ovarian cancer was higher in current and past users of either estrogen only or combined HRT compared to women who never used hormone therapy. The risk did not differ according to different hormone formulations, duration of use, or the route by which the hormone treatment was taken. The study confirmed the higher risk of ovarian cancer in users of hormone therapy shown by previous studies.

IARC review
The International Agency for Research on Cancer (IARC) published a review of combined HRT in 2007 which found sufficient evidence for an increased risk of breast cancer and a potentially protective effect for colorectal cancer.

Reports on the health benefits and risks of HRT
International Agency for Research on Cancer
Monograph 91 on Combined Estrogen-Progestogen Menopausal Therapy

Health Canada
Benefits and Risks of Hormone Replacement Therapy
The Safe Use of Natural Health Products During Menopause

American Cancer Society
Menopausal Hormone Replacement Therapy and Cancer Risk

National Institutes for Health
Menopausal Hormone Therapy Information

National Cancer Institute
Postmenopausal Hormone Use

Society of Obstetricians and Gynaecologists of Canada

Research on cancer risk of HRT
Journal of the American Medical Association
Hormone Therapy and Ovarian Cancer (July 2009)
Health Risks and Benefits 3 years after stopping randomized treatment with estrogen and progestin (March, 2008)
Effects on Breast Cancer and Mammograms (June, 2003)
Risks and Benefits of Estrogen Plus Progestin in Healthy Postmenopausal Women (July, 2002)

New England Journal of Medicine
Breast Cancer after Use of Estrogen plus Progestin in Postmenopausal Women (February 2009)
The Decrease in Breast-Cancer Incidence in 2003 in the United States (April, 2007)

American Journal of Epidemiology
Estrogen plus progestin therapy and breast cancer in recently postmenopausal women (March, 2008)

Research on other health benefits and risks of HRT
Journal of the American Medical Association
Gynecologic Factors and Associated Diagnostic Procedures (Oct, 2003)
Bone Density and Risk of Fractures (Oct, 2003)
Stroke (May, 2003)
Dementia (May, 2003)
Cognitive Functioning (May, 2003)

Women who decide not to take hormone replacement therapy (HRT) and who experience many menopausal symptoms often seek relief in other ways. Not all of the alternatives to HRT have been scientifically proven, but many women do find them helpful.

What you can do to help sleep troubles

• Exercise. Being active relieves stress and improves overall well-being which may help you to sleep better.
• Try relaxation techniques (deep breathing, massage or yoga). These may help reduce your stress levels.
• Sip a chamomile tea or tea containing valerian at bedtime. Avoid caffeine and alcohol as they can make menopausal symptoms worse.

What you can do to control hot flashes

• Get as much exercise as you can.
• Choose light clothing and wear it in layers that can be removed.

What you can do to relieve vaginal dryness

• Use a water-soluble lubricant or moisturizer available at your pharmacy.
• Ask your doctor about a vitamin E vaginal suppository or cream to help relieve symptoms.

Not all the above alternatives to HRT have been tested to evaluate side effects. Hormone replacement therapy may still be useful to ease the symptoms of menopause for short-term use over several months – when the alternatives to HRT do not work and the symptoms are severe.

Always check with your doctor before making a decision about hormone replacement therapy, taking any herbal products or making any lifestyle changes.