Hormone replacement therapy, also referred to as HRT, hormone therapy, combined hormone therapy, estrogen replacement therapy, and ERT, is one of the more controversial medical approaches for managing the health concerns of aging women. Hormone replacement therapy originally was seen as a good way to manage the severe menopause symptoms, such as hot flashes and insomnia, experienced by some women around the time of menopause.
Initial Impressions on Hormone Replacement Therapy
Early reports in the 1980s suggested that hormone replacement therapy could reduce the risk of several chronic diseases, such as heart disease, stroke, osteoporosis, and dementia. These observations led to development of a long-term clinical trial in 1991, called the Women's Health Initiative (WHI). WHI included 161,808 healthy, postmenopausal women, and was designed to study how hormone replacement therapy affects the risk of heart disease, bone breaks (fractures), and breast and colorectal cancers.
Study Results on Hormone Replacement Therapy Unexpected
The initial results from WHI indicated that hormone replacement therapy increased the risk of heart disease. Many health experts had expected that hormone therapy would protect against heart disease, but WHI did not bear this out.
The WHI research also revealed that hormone replacement therapy increased risk of breast cancer and may increase the risk of stroke and dementia as well. Clearly, when it comes to heart disease, brain function, and vascular health, hormone replacement therapy is not the answer.
Hormone Replacement Therapy and Colon Cancer
The picture has been less clear about hormone replacement therapy (HRT) and colorectal cancer. The initial information gathered from the WHI study indicated that taking hormones could reduce colon cancer risk in postmenopausal women, but unfortunately, this hasn't settled the question.
A comprehensive review of controlled trials on hormone replacement therapy concluded that HRT significantly reduces the risk of colon cancer in postmenopausal women, but a recent look at the WHI study data concluded exactly the opposite: Hormone replacement therapy does not protect postmenopausal women from colon cancer.
Further confusing the issue is a large study out of Israel suggesting that hormone replacement therapy protects against colon cancer, but only in women who do not regularly use aspirin or who do not participate in sports or exercise vigorously on a regular basis. If this leaves your head spinning, you're not alone.
What is the Deal with Hormone Replacement Therapy and Colon Cancer Risk?
It's hard to keep this all straight, but a thoughtful look at the research on hormone replacement therapy does yield some useful information. Keep the following in mind when deciding if hormone replacement therapy is something you should consider to reduce your risk of colon cancer:
- It's not clear that hormone replacement therapy decreases colon cancer risk in postmenopausal women. However, one positive result of research conducted to date is that no studies suggest HRT markedly increases colon cancer risk.
- Consider the type of hormone replacement therapy. There are different types of HRT, some of which include estrogen only and others which include estrogen plus progestin. The different hormone therapy options can have different effects on the risk of disease in postmenopausal women. If you are considering HRT, talk to your doctor about which, if any, of these options might be an safe for you.
- Consider your personal and family medical histories. For example, if you have a strong family history of colon cancer, but no family history of heart disease or breast cancer, HRT might be a reasonable option. If, on the other hand, you have heart disease or it runs in your family, the harm of hormone replacement therapy may outweigh any colon cancer risk reduction benefit.
- Take advantage of other ways to reduce colon cancer risk. One of the reasons why HRT may not have reduced risk in certain women in the Israeli study is that the other factors that reduce risk, including regular aspirin use and exercise, matter more for colon cancer. Regular aspirin use has possible downsides, so don't go this route without first talking to your doctor. Exercise, on the other hand, is considered a safe, effective way to reduce colon cancer risk for most healthy adults. If there is no medical reason that prevents you from exercising, get moving today!
- Get screened. Catching colon cancer early with screening, before it spreads beyond the colon, is the single best way to ensure that if you have colon cancer, you will be treated successfully and cured.
- Get and stay lean. Maintaining a healthy body weight is one of the best ways to reduce colon cancer risk. In fact, research shows that about a third of all colon cancers are due to having a body mass index (BMI) greater than 22.5 kilograms per meter squared (kg/m2). You can check your own BMI to see if you fall into a higher-risk colon cancer category based on your body weight.
- Focus on food. Not only is a healthy diet good for keeping you lean, the right foods can reduce colon cancer risk independently.
- Don't smoke and quit if you do. Many people are aware of the more obvious risks of smoking, such as lung cancer, heart disease, and emphysema, but many don't know that smoking increases colon cancer risk too.
Sources:
Farquhar C, Marjoribanks J, Lethaby A, Suckling JA, and Lamberts Q. "Long term hormone therapy for perimenopausal and postmenopausal women." Cochrane Database of Systematic Reviews 2008 2:CD004143.
Prentice RL, Pettinger M, Beresford SAA, Wactawski-Wende J, Hubbell FA, Stefanick ML, and Chlebowski RT. "Colorectal Cancer in Relation to Postmenopausal Estrogen and Estrogen Plus Progestin in the Women's Health Initiative Clinical Trial and Observational Study." Cancer Epidemiology, Biomarkers & Prevention 2009 18:1531–1537.
Rennert G, Rennert HS, Pinchev M, Lavie O, and Gruber SB. "Use of Hormone Replacement Therapy and the Risk of Colorectal Cancer." Journal of Clinical Oncology 2009 Aug 24 [Epub ahead of print].
