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, 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. The lower, narrow end of the uterus is the cervix, which leads to the vagina.

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 about uterine sarcoma.

Obesity and having metabolic syndrome may increase the risk of endometrial cancer.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for endometrial cancer.

Risk factors for endometrial cancer include the following:

• Taking estrogen-only hormone replacement therapy (HRT) after menopause.
• Taking tamoxifen to prevent or treat breast cancer.
• Obesity.
• Having metabolic syndrome.
• Having type 2 diabetes.
• Exposure of endometrial tissue to estrogen made by the body. This may be caused by:
  • Never giving birth.
  • Menstruating at an early age.
  • Starting menopause at a later age.
• Having polycystic ovary syndrome.
• Having a family history of endometrial cancer in a first-degree relative (mother, sister, or daughter).
• Having certain genetic conditions, such as Lynch syndrome.
• Having endometrial hyperplasia.

Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.

Taking tamoxifen for breast cancer or taking estrogen alone (without progesterone) can increase the risk of endometrial cancer.

Endometrial cancer may develop in breast cancer patients who have been treated with tamoxifen. A patient who takes this drug and has abnormal vaginal bleeding should have a follow-up exam and a biopsy of the endometrial lining if needed. Women taking estrogen (a hormone that can affect the growth of some cancers) alone also have an increased risk of endometrial cancer. Taking estrogen combined with progesterone (another hormone) does not increase a woman’s risk of endometrial cancer.

Signs and symptoms of endometrial cancer include unusual vaginal bleeding or pain in the pelvis.

These and other signs and symptoms may be caused by endometrial cancer or by other conditions. Check with your doctor if you have any of the following:

• Vaginal bleeding or discharge not related to menstruation (periods).
• Vaginal bleeding after menopause.
• Difficult or painful urination.
• Pain during sexual intercourse.
• Pain in the pelvic area.

Tests that examine the endometrium are used to diagnose endometrial cancer.

Because endometrial cancer begins inside the uterus, it does not usually show up in the results of a Pap test. For this reason, a sample of endometrial tissue must be removed and checked under a microscope to look for cancer cells. One of the following procedures may be used:

• Endometrial biopsy: The removal of tissue from the endometrium (inner lining of the uterus) by inserting a thin, flexible tube through the cervix and into the uterus. The tube is used to gently scrape a small amount of tissue from the endometrium and then remove the tissue samples. A pathologist views the tissue under a microscope to look for cancer cells.
• Dilatation and curettage: A procedure to remove samples of tissue from the inner lining of the uterus. The cervix is dilated and a curette (spoon-shaped instrument) is inserted into the uterus to remove tissue. The tissue samples are checked under a microscope for signs of disease. This procedure is also called a D&C.
• Hysteroscopy: A procedure to look inside the uterus for abnormal areas. A hysteroscope is inserted through the vagina and cervix into the uterus. A hysteroscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.

Other tests and procedures used to diagnose endometrial cancer include the following:

• Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Transvaginal ultrasound exam: A procedure used to examine the vagina, uterus, fallopian tubes, and bladder. An ultrasound transducer (probe) is inserted into the vagina and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The doctor can identify tumors by looking at the sonogram.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• The stage of the cancer (whether it is in the endometrium only, involves the uterus wall, or has spread to other places in the body).
• How the cancer cells look under a microscope.
• Whether the cancer cells are affected by progesterone.

Endometrial cancer can usually be cured because it is usually diagnosed early.