The process of finding out how far the cancer has spread is called staging. Information is gathered from exams and diagnostic tests to determine the size of the tumor, how deeply the tumor has invaded tissues within and around the cervix, and the spread to lymph nodes or distant organs (metastasis). This is an important process because the stage of the cancer is the key factor in selecting the right treatment plan.

A staging system is a way for members of the cancer care team to summarize the extent of a cancer's spread. Cervical cancer is staged with the FIGO (International Federation of Gynecology and Obstetrics) System of Staging. This system classifies the disease in stages 0 through IV. It is based on clinical staging rather than surgical staging. This means that the extent of disease is evaluated by the doctor's physical examination and a few other tests that are done in some cases, such as cystoscopy and proctoscopy.

If surgery is done, it may reveal that the cancer has spread more than the doctors initially thought. This new information may change the treatment plan, but it does not change the patient's FIGO stage. This staging system is different from those for other cancers. The systems for other cancers take into account whether the cancer has spread to local lymph nodes. The FIGO doesn't, even though we know the outlook worsens if the cancer has spread to lymph nodes.

Stage 0: The cancer cells are very superficial (only affecting the surface) are found only in the layer of cells lining the cervix, and they have not grown into (invaded) deeper tissues of the cervix. This stage is also called carcinoma in situ (CIS) or cervical intraepithelial neoplasis (CIN) grade III.

Stage I: In this stage the cancer has invaded the cervix, but it has not spread anywhere else.

Stage IA: This is the earliest form of stage I. There is a very small amount of cancer, and it can be seen only under a microscope.

• Stage IA1: The area of invasion is less than 3 mm (about 1/8-inch) deep and less than 7 mm (about 1/4-inch) wide.

• Stage IA2: The area of invasion is between 3 mm and 5 mm (about 1/5-inch) deep and less than 7 mm (about 1/4-inch) wide.

Stage IB: This stage includes Stage I cancers that can be seen without a microscope. This stage also includes cancers that can only be seen with a microscope if they have spread deeper than 5 mm (about 1/5 inch) into connective tissue of the cervix or are wider than 7 mm.

• Stage IB1: The cancer can be seen but it is not larger than 4 cm (about 1 3/5 inches).

• Stage IB2: The cancer can be seen and is larger than 4 cm.

Stage II: In this stage, the cancer has grown beyond the cervix and uterus, but hasn't spread to the walls of the pelvis or the lower part of the vagina.

• Stage IIA: The cancer has not spread into the tissues next to the cervix (called the parametria). The cancer may have grown into the upper part of the vagina.

• Stage IIB: The cancer has spread into the tissues next to the cervix.

Stage III: The cancer has spread to the lower part of the vagina or the pelvic wall. The cancer may be blocking the ureters (tubes that carry urine from the kidneys to the bladder).

• Stage IIIA: The cancer has spread to the lower third of the vagina but not to the pelvic wall.

• Stage IIIB: The cancer has grown into the pelvic wall. If the tumor has blocked the ureters (a condition called hydronephrosis) it is also a stage IIIB.

Note: In the alternate staging system by the American Joint Committee on Cancer, stage IIIB is defined by the fact that the cancer has spread to lymph nodes in the pelvis.

Stage IV: This is the most advanced stage of cervical cancer. The cancer has spread to nearby organs or other parts of the body.

• Stage IVA: The cancer has spread to the bladder or rectum, which are organs close to the cervix.

• Stage IVB: The cancer has spread to distant organs beyond the pelvic area, such as the lungs.

Five-year survival rates by stage

Below are listed the chances a woman will live 5 years after treatment for the various stages of cervical cancer. These are overall survival figures, so they also include women who die of other causes. The numbers are approximate and come from women treated more than 10 years ago.

Stage	5-Year Survival Rate
IA	Above 95%
IB1	Around 90%
IB2	Around 80%-85%
IIA/B	Around 75%-78%
IIIA/B	Around 47%-50%
IV	Around 20%-30%