Cancer prevention 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.

Endometrial cancer is a disease in which malignant (cancer) cells form in the tissues of the endometrium.

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.

Endometrial cancer is most common in postmenopausal women.

Endometrial cancer is diagnosed most often in postmenopausal women at an average age of 60 years.

Since the mid-2000s, the number of new cases of endometrial cancer has increased slightly each year. From 2015 to 2019, the number of deaths from endometrial cancer increased by about 1% per year.

Avoiding risk factors and increasing protective factors may help prevent cancer.

Avoiding cancer risk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking 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.

The following risk factors increase the risk of endometrial cancer:

Endometrial hyperplasia

Endometrial hyperplasia is an abnormal thickening of the endometrium (lining of the uterus). It is not cancer, but in some cases, it may lead to endometrial cancer.

Estrogen

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 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 therapy (HT). The use of HT that contains only estrogen increases the risk of endometrial cancer, and the risk grows higher the longer the estrogen is used. 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 therapy. For postmenopausal women, taking estrogen in combination with progestin does not increase the risk of endometrial cancer, but it does increase the risk of breast cancer. (See the Breast Cancer Prevention summary for more information.)

• 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

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. Tamoxifen is used to prevent breast cancer in women who are at high risk for the disease. However, using tamoxifen for more than 2 years 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. However, it does not have estrogen-like effects on the uterus and has not been shown to increase the risk of endometrial cancer.

Obesity, weight gain, metabolic syndrome, and diabetes

Obesity, gaining weight as an adult, or having metabolic syndrome increases the risk of endometrial cancer. Obesity is related to other risk factors such as high estrogen levels, having extra fat around the waist, polycystic ovary syndrome, and lack of physical activity.

Having metabolic syndrome increases the risk of endometrial cancer. Metabolic syndrome is a condition that includes extra fat around the waist, high blood sugar, high blood pressure, and high levels of triglycerides (a type of fat) in the blood.

Having type 2 diabetes may increase the risk of endometrial cancer.

Genetic factors

Lynch syndrome is an inherited disorder caused by changes in certain genes. Women who have Lynch syndrome have a much higher risk of developing endometrial cancer than women who do not have Lynch syndrome.

Polycystic ovary syndrome (a disorder of the hormones made by the ovaries), and Cowden syndrome are inherited conditions that are linked to an increased risk of endometrial cancer.

Women with a family history of endometrial cancer in a first-degree relative (mother, sister, or daughter) are also at increased risk of endometrial cancer.

The following protective factors decrease the risk of endometrial cancer:

Pregnancy and breast-feeding

Estrogen levels are lower during pregnancy and when breast-feeding. The risk of endometrial cancer is lower in women who have had children. Breastfeeding also decreases the risk of endometrial cancer.

Hormonal contraceptives

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

While taking birth control pills, women have a higher risk of blood clots, stroke, and heart attack, especially women who smoke and are older than 35 years.

New data suggest that other hormonal contraceptives, such as birth control devices that are inserted into a woman's uterus, may also decrease the risk of endometrial cancer.

Weight loss

It is not known if losing weight decreases the risk of endometrial cancer. However, having bariatric surgery (a surgery that changes how your digestive system works so you will lose weight) decreases the risk of endometrial cancer. After bariatric surgery, other obesity-related conditions, such as diabetes and metabolic syndrome often improve or go away.

Having bariatric surgery also includes risks, such as infection, blood clots, breathing or heart problems, and digestive issues.

Physical activity

Physical activity (exercise) may lower the risk of endometrial cancer. This includes any physical activity you do at your job or at home.

It is not known if the following factor affects the risk of endometrial cancer:

Fruits, vegetables, and vitamins

A diet that includes, fruits, vegetables, phytoestrogen, soy, and vitamin D has not been found to affect the risk of endometrial cancer.

Taking multivitamins has little or no effect on the risk of common cancers, including endometrial cancer.

Cigarette smoking is also a protective factor for endometrial cancer; however, there are many known harms of smoking that outweigh this benefit.

Although cigarette smoking has been linked to a decreased risk of endometrial cancer, it has been proven to have many other serious harmful effects. Studies show that women who smoke at least 20 cigarettes a day may have a lower risk of endometrial cancer than women who do not smoke. The risk of endometrial cancer is even lower in postmenopausal women who smoke.

However, there are many proven harms of smoking. Cigarette smokers live about 10 years less than nonsmokers. Smoking increases the risk of many types of cancer. These include:

• Lung cancer.
• Throat cancer.
• Mouth cancer.
• Nasal cavity cancer.
• Esophageal cancer.
• Stomach cancer.
• Pancreatic cancer.
• Kidney cancer.
• Bladder cancer.
• Cervical cancer.
• Acute myeloid leukemia.

Cigarette smokers also have an increased risk of other health problems, including:

• Heart disease.
• Stroke.
• Emphysema.
• Bronchitis.