Cancer is when cells in the body change and grow out of control. To help you understand what happens when you have cancer, let’s look at how your body works normally. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them, and they die when your body does not need them any longer.

Cancer is made up of abnormal cells that grow even though your body doesn’t need them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If cancer cells are in the body long enough, they can grow into (invade) nearby areas. They can also break off and spread to other parts of the body (metastasis).

Endometrial cancer starts in the cells that form the inner lining of the uterus (which is called the endometrium).

You may hear endometrial cancer called uterine cancer. It's actually one of two main types of uterine cancer. The other is called uterine sarcoma. It starts in the muscle layer of the uterus, not the lining.

Endometrial cancer is the most common type of cancer in the uterus. It usually takes years to develop. It most often occurs in women who have already gone through menopause. It is highly curable when found early.

The uterus is an organ. It’s part of the female reproductive system. You may know it as the womb. The uterus is usually pear-shaped and about the size of a fist. It is located in the lower belly (pelvic area) between your bladder and your rectum. Your uterus is connected to your fallopian tubes. These tubes help carry eggs from your ovaries into the uterus. The small opening that connects the uterus to your vagina is the cervix.

The uterus is made up of three layers:

• Endometrium. This is the inner lining.

• Myometrium. This is the middle muscle layer.

• Serosa. This is the outer smooth layer.

The uterus protects a growing baby during pregnancy. During labor, the myometrium muscle tissue helps push the baby out through the cervix. The smooth serosa makes it easy for the uterus to move in the pelvis as needed.

In women who still have their periods, one of the ovaries releases an egg into a fallopian tube each month. During this time, the endometrium becomes thicker as it gets ready to receive a fertilized egg. If the egg connects with a male sperm cell, this fertilized egg attaches to the endometrium. If the egg is not fertilized, it travels out of the uterus along with the endometrial lining as a woman's period (menstrual flow).

If endometrial cancer spreads, it tends to grow into the muscle layer of the uterus, the myometrium, and then may go to places near the uterus. This may be the fallopian tubes, ovaries, cervix, vagina, or lymph nodes. It can also spread to the bladder or rectum. Advanced stages of endometrial cancer can spread as far as the bones and lungs. Most cases of endometrial cancer are found in the early stages before they have spread outside the uterus.

Cancer that spreads to other parts of the body is called metastatic cancer. The process is called metastasis. Metastasis is a complex process. The cancer cells of the tumor grow into other tissues, blood vessels, and the lymph system. They then travel through the bloodstream or lymph system to reach other parts of the body where they grow into new tumors.

If you have questions about endometrial cancer, talk with your healthcare provider. Your healthcare provider can help you understand more about this cancer.

The main symptom of endometrial cancer is unusual vaginal bleeding. This occurs in almost all people with endometrial cancer. The bleeding may include:

• Changes in the kind of bleeding during periods, such as a very long period or heavy bleeding

• Bleeding between periods

• Any vaginal bleeding after menopause

For most people, abnormal vaginal bleeding is the only symptom they have. But other symptoms may include:

• Non-bloody vaginal discharge 

• Pain when urinating

• Pain during sex

• Pain, pressure, or a lump in the pelvic area or lower belly (lower abdomen)

• Losing weight without trying

Tell your healthcare provider if you have any unusual bleeding from the vagina. Tell them if you have any bleeding at all after menopause. Even if it is just a bit of spotting or slight bloody discharge, it is very important to let your healthcare provider know, as this small amount of bleeding may be the only sign of a problem.

Some people develop endometrial cancer while they are entering menopause. During this time, periods may get heavier or lighter. This may not be a symptom of menopause. Make sure to tell your healthcare provider about any change in vaginal bleeding during this time.

Some of these symptoms may be caused by other health problems. But it is important to see your healthcare provider if you have these symptoms. Only a healthcare provider can tell if you have cancer.