The stage of a cancer is how much and how far the cancer has spread in your body. Your doctor uses exams and tests to find out the size of the cancer and where it is. They can also see if the cancer has grown into nearby areas, and if it has spread to other parts of your body. The stage of a cancer is one of the most important things to know when deciding how to treat the cancer and gives information that helps when discussing possible outcomes.

Endometrial cancer starts in the inner lining of the uterus (the endometrium). Over time, the cancer can grow into the muscle layers of the wall of the uterus (the myometrium) and into nearby tissues and lymph nodes. Then, like all cancers, it can spread (metastasize) to other parts of the body.

Endometrial cancer is often staged after surgery (called surgical staging). This is done by looking at the removed uterus, fallopian tubes, ovaries, and lymph nodes in a pathology lab.

It's very important that your cancer be diagnosed by an expert, such as a gynecologic oncologist. This is a specialist with advanced training. They're trained in the diagnosis and treatment of female cancers, such as endometrial cancer.

Doctors use different systems to stage cancer. There are two systems used most often to stage endometrial cancer:

• FIGO (International Federation of Gynecology and Obstetrics) staging system
• AJCC (American Joint Committee on Cancer) TNM staging system

The two systems are much the same. They both use the TNM system. Here's what the letters stand for:

• T tells how far the main tumor has spread into the uterus and nearby tissue.
• N tells if the lymph nodes in the area of the original tumor have cancer in them.
• M tells if the cancer has spread (metastasized) to distant organs in the body. These may include the liver, lungs, bones, or lymph nodes in another part of the body.

Numbers or letters after T, N, and M provide more details about each of these factors. There are also two other values that can be assigned:

• X means the doctor does not have enough information to assess the extent of the main tumor (TX), or if the lymph nodes have cancer cells in them (NX).
• 0 means no sign of cancer, such as no sign of lymph node spread (N0).

Stage groupings are determined by combining the T, N, and M values from the TNM system. These groupings give an overall description of your cancer. A stage grouping is listed as a Roman numeral and can have a value of I through IV (1 through 4). The higher the number, the more advanced your cancer is.

These are the stage groupings of endometrial cancer and what they mean:

Stage I. The cancer is in the endometrium (inside the uterus) and may be growing into the glands of the cervix. (The cervix is the lower end of the uterus that connects to the vagina.) It's not in the supporting tissue of the cervix (the stroma), but may be growing into the muscle (myometrium) of the uterus. It has not spread to lymph nodes or other parts of the body. This stage may be divided as:

• Stage IA. The cancer is in the endometrium only, and it may have grown less than halfway through the myometrium (the muscle layer of the uterus wall). It has not spread to lymph nodes or other parts of the body.
• Stage IB. The cancer is in the endometrium, and it has grown halfway or more through the myometrium. It has not spread to lymph nodes or other parts of the body.

Stage II. The cancer has spread from the endometrium to the stromal connective tissue in the cervix. It may or may not involve the glands of the cervix. It has not spread outside the uterus or to lymph nodes or distant parts of the body.

Stage III. The cancer has spread beyond the uterus and cervix, but it is still only in the pelvic area. It has not spread to the inner linings of the bladder or rectum. It has not spread to lymph nodes or distant parts of the body.

• Stage IIIA. The cancer has spread to the outer surface (the serosa) of the uterus, the fallopian tubes, ovaries, or ligaments of the uterus. It has not spread to lymph nodes or distant parts of the body.
• Stage IIIB. The cancer has spread to the vagina or to the tissues surrounding the uterus (the parametrium). It has not spread to lymph nodes or distant parts of the body.
• Stage IIIC. The cancer is growing inside the uterus, and it may or may not have spread to nearby tissues. It has not spread to the inner linings of the bladder or rectum. And one of these is true:
  • Stage IIIC1. It has spread to lymph nodes in the pelvis, but it hasn't spread to lymph nodes around the aorta or distant parts of the body.
  • Stage IIIC2. It has spread to lymph nodes around the aorta but not to distant parts of the body.

Stage IV. The cancer has spread beyond the uterus and outside the pelvis and one of these is true:

• Stage IVA. The cancer has spread to the inner lining of the rectum and/or bladder mucosa. It may or may not have spread to nearby lymph nodes, but it has not spread to distant parts of the body.
• Stage IVB. The cancer has spread to lymph nodes in the groin or upper abdomen (belly), or it has spread to organs away from the uterus, such as the lungs, liver, or bones. It may also have spread to other lymph nodes.

Once your cancer is staged, your doctor will talk with you about what the stage means for you. Ask questions and talk about your concerns.