Endometrial Cancer Prevention (PDQ®)

Contents of This Summary

What is prevention?

Cancerprevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.

Different ways to prevent cancer are being studied, including:

• Changing lifestyle or eating habits.
• Avoiding things known to cause cancer.
• Taking medicines to treat a precancerous condition or to keep cancer from starting.

General Information About Endometrial Cancer

The endometrium is the lining of the uterus. The uterus is part of the female reproductive system. It is a hollow, pear-shaped, muscular organ in the pelvis, where a fetus grows.

Cancer of the endometrium is different from cancer of the muscle of the uterus, which is called sarcoma of the uterus. See the PDQ summary on Uterine Sarcoma Treatment for more information.

Endometrial cancer usually occurs in women after menopause, and affects more white women than black women. Black women diagnosed with endometrial cancer are more likely to have more advanced disease at diagnosis, and are more likely to die from endometrial cancer than white women.

Endometrial Cancer Prevention

Avoiding cancerrisk factors such as smoking, being overweight, and lack of exercise may help prevent certain cancers. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.

Estrogen is a hormone made by the body. It helps the body develop and maintain female sex characteristics. Estrogen can affect the growth of some cancers, including endometrial cancer. A woman's risk of developing endometrial cancer is increased by being exposed to estrogen in the following ways:

• Estrogen-only hormone replacement therapy: Estrogen may be given to replace the estrogen no longer produced by the ovaries in postmenopausal women or women whose ovaries have been removed. This is called hormone replacement therapy (HRT), or hormone therapy (HT). The use of hormone replacement therapy that contains only estrogen increases the risk of endometrial cancer. For this reason, estrogen therapy alone is usually prescribed only for women who do not have a uterus.

  When estrogen is combined with progestin (another hormone), it is called combination estrogen-progestin replacement therapy. For postmenopausal women, taking estrogen in combination with progestin does not increase the risk of endometrial cancer.

• Early menstruation: Beginning to have menstrual periods at an early age increases the number of years the body is exposed to estrogen and increases a woman's risk of endometrial cancer.
• Late menopause: Women who reach menopause at an older age are exposed to estrogen for a longer time and have an increased risk of endometrial cancer.
• Never being pregnant: Because estrogen levels are lower during pregnancy, women who have never been pregnant are exposed to estrogen for a longer time than women who have been pregnant. This increases the risk of endometrial cancer.

Tamoxifen is one of a group of drugs called selective estrogen receptor modulators, or SERMs. Tamoxifen acts like estrogen on some tissues in the body, such as the uterus, but blocks the effects of estrogen on other tissues, such as the breast. When tamoxifen is used to prevent breast cancer in women who are at high risk for the disease, it increases the risk of endometrial cancer. This risk is greater in postmenopausal women.

Raloxifene is a SERM that is used to prevent bone weakness in postmenopausal women. It does not have estrogen-like effects on the uterus and has not been shown to increase the risk of endometrial cancer. Other SERMs are being studied in clinical trials.

Hereditary nonpolyposis colon cancer (HNPCC) syndrome is an inheriteddisorder caused by changes in certain genes. Women who have HNPCC syndrome have a much higher risk of developing endometrial cancer than women who do not have HNPCC syndrome.

Women who have polycystic ovary syndrome (a disorder of the hormones made by the ovaries) have an increased risk of endometrial cancer.

Obesity increases the risk of endometrial cancer. This may be because obesity is related to other risk factors such as estrogen levels, polycystic ovary syndrome, lack of physical activity, and a diet that is high in saturated fats.

It is not known if losing weight decreases the risk of endometrial cancer.

Taking contraceptives that combine estrogen and progestin (combination oral contraceptives) decreases the risk of endometrial cancer. The protective effect of combination oral contraceptives increases with the length of time they are used, and can last for many years after oral contraceptive use has been stopped.

Physical activity may lower the risk of endometrial cancer.

Estrogen levels are lower during pregnancy and when breast-feeding. Being pregnant and/or breast-feeding may lower the risk of endometrial cancer.

A diet low in saturated fats and high in fruits and vegetables may lower the risk of endometrial cancer. The risk may also be lowered when soy-based foods are a regular part of the diet.

Cancer preventionclinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.

Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check NCI's PDQ Cancer Clinical Trials Registry for endometrial cancer prevention trials that are now accepting patients.

Get More Information From NCI

Call 1-800-4-CANCER

For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. Deaf and hard-of-hearing callers with TTY equipment may call 1-800-332-8615. The call is free and a trained Cancer Information Specialist is available to answer your questions.

Chat online

The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 9:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.

Write to us

For more information from the NCI, please write to this address:

• NCI Public Inquiries Office
• Suite 3036A
• 6116 Executive Boulevard, MSC8322
• Bethesda, MD 20892-8322

Search the NCI Web site

The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use our “Best Bets” search box in the upper right hand corner of each Web page. The results that are most closely related to your search term will be listed as Best Bets at the top of the list of search results.

There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.

Find Publications

The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237), TTY at 1-800-332-8615.