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.

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

Endometrial cancer may develop in breast cancer patients who have been treated with tamoxifen. A patient taking this drug should have a pelvic exam every year and report any vaginal bleeding (other than menstrual bleeding) as soon as possible. Women taking estrogen (a hormone that can affect the growth of some cancers) alone have an increased risk of developing endometrial cancer. Taking estrogen in combination with progesterone (another hormone) does not increase a woman’s risk of this cancer.

Possible signs of endometrial cancer include unusual vaginal discharge or pain in the pelvis.

These and other symptoms may be caused by endometrial cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

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

Tests that examine the endometrium are used to detect (find) and 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 examined 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 surgical procedure to remove samples of tissue or the inner lining of the uterus. The cervix is dilated and a curette (spoon-shaped instrument) is inserted into the uterus to remove tissue. Tissue samples may be taken for biopsy. This procedure is also called a D&C.

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

The prognosis (chance of recovery) and treatment options depend on the following:

• The stage of the cancer (whether it is in the endometrium only, involves the whole uterus, 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 is highly curable.