Key Points for This Section

Endometrial cancer is a disease in which malignant (cancer) cells form in the tissues of the endometrium. In the United States, endometrial cancer is the most common invasive cancer of the female reproductive system. Health history and certain medicines can affect the risk of developing endometrial cancer.

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

The endometrium is the innermost lining of the uterus. The uterus is a hollow, muscular organ in a woman's pelvis. The uterus is where a fetus grows. In most nonpregnant women, the uterus is about 3 inches long.

Cancer of the endometrium is different from cancer of the muscle of the uterus, which is called uterine sarcoma. Refer to the PDQ summary on Uterine Sarcoma Treatment ¹ for more information.

In the United States, endometrial cancer is the most common invasive cancer of the female reproductive system.

Endometrial cancer occurs more often in white women than in black women. When endometrial cancer is diagnosed in black women, it is usually more advanced and less likely to be cured.

The number of new cases of endometrial cancer in the United States decreased from 1978 to 1988 and has stayed about the same since then. The number of deaths from endometrial cancer has decreased since 1974.

Health history and certain medicines can affect the risk of developing endometrial cancer.

Anything that increases your chance of getting a disease is called a risk factor. Risk factors for endometrial cancer include the following:

• Taking tamoxifen for treatment or prevention of breast cancer.
• Taking estrogen alone. (Taking estrogen in combination with progesterone does not appear to increase the risk of endometrial cancer.)
• Being overweight.
• Eating a high-fat diet.
• Never giving birth.
• Beginning menstruation at an early age.
• Reaching menopause at an older age.
• Having the gene for hereditary non-polyposis colon cancer (HNPCC).
• Being white.

Glossary Terms

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

Having to do with the endometrium (the layer of tissue that lines the uterus).

The layer of tissue that lines the uterus.

A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis, and other conditions.

The developing offspring from 7 to 8 weeks after conception until birth.

HNPCC. An inherited disorder in which affected individuals have a higher-than-normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also called HNPCC and Lynch syndrome.

The time of life when a woman's menstrual periods stop. A woman is in menopause when she hasn't had a period for 12 months in a row. Also called change of life.

Periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days when a woman is not pregnant.

A part of the body that performs a specific function. For example, the heart is an organ.

The lower part of the abdomen, located between the hip bones.

A type of hormone made by the body that plays a role in the menstrual cycle and pregnancy. Progesterone can also be made in the laboratory. It may be used as a type of birth control and to treat menstrual disorders, infertility, symptoms of menopause, and other conditions.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

A cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate and Nolvadex.

The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a baby grows. Also called the womb.