Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
One tool that doctors use to describe the stage is the TNM system. This system judges three factors: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are divided into smaller groups that help describe the tumor in even more detail. The Roman numerals in parentheses are stages used in another widely used staging system from the Federation Internationale de Gynecologie et d'Obstetrique, or FIGO.
TX: The primary tumor cannot be evaluated. More tests may be needed.
T0: There is no primary tumor.
Tis: This stage is called carcinoma (cancer) in situ, which means that the cancer is found only in the layer of cells lining the cervix and has not spread deeper into the cervix.
T1/FIGO I: The carcinoma is found only in the cervix.
T1a/FIGO IA: Invasive carcinoma was diagnosed only by microscopy (viewing cervical tissue or cells under a microscope). Note: Any tumor found macroscopically (large enough to be recognized by imaging tests or to be seen or felt by the doctor) is called stage T1b or FIGO IB.
T1a1/FIGO IA1: There is a cancerous area of 3.0 millimeters (mm) or smaller in depth, and 7.0 mm or smaller in length.
T1a2/FIGO IA2: There is a cancerous area larger than 3.0 mm but not larger than 5.0 mm in depth, and 7.0 mm or smaller in length.
T1b/FIGO IB: In this stage, the doctor can see the lesion, and the cancer is found only in the cervix, or there is a microscopic lesion (one able to be seen using a microscope) that is larger than a stage T1a2/FIGO IA2 tumor (see above). The cancer may have been found because of a physical examination, laparoscopy, or other imaging methods (see Diagnosis).
T1b1/FIGO IB1: The tumor is 4.0 centimeters (cm) or smaller.
T1b2/FIGO IB2: The tumor is larger than 4.0 cm.
T2/FIGO II: The cancer has grown beyond the uterus but not to the pelvic wall or to the lower third of the vagina.
T2a/FIGO IIA: The tumor has not spread to the tissue next to the cervix, also called the parametrial area.
T2a1/FIGO IIA1: The tumor is 4.0 cm or smaller.
T2a2/FIGO IIA2: The tumor is larger than 4.0 cm.
T2b/FIGO IIB: The tumor has spread to the parametrial (tissue surrounding the uterus) area.
T3/FIGO III: The tumor extends to the pelvic wall, and/or involves the lower third of the vagina, and/or causes hydronephrosis (swelling of the kidney) or a nonfunctioning kidney.
T3a/FIGO IIIA: The tumor involves the lower third of the vagina, but it has not grown into the pelvic wall.
T3b/FIGO IIIB: The tumor has grown into the pelvic wall and/or causes hydronephrosis or nonfunctioning kidneys.
T4/FIGO IVA: The tumor has spread to the mucosa (lining) of the bladder or rectum and grown beyond the pelvis.
Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the cervix are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0 (N plus zero): The tumor has not spread to the regional lymph nodes.
N1/FIGO IIIB: The tumor has spread to the regional lymph node(s).
Distant metastasis. The "M" in the TNM system indicates whether the cancer has spread to other parts of the body.
M0 (M plus zero): There is no distant metastasis.
M1/FIGO IVB: There is distant metastasis.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage 0: The tumor is called carcinoma in situ. In other words, the cancer is found only in the first layer of cells lining the cervix, not in the deeper tissues (Tis, N0, M0). Carcinoma in situ is not considered to be an invasive cancer.
Stage I: The cancer has spread from the cervix lining into the deeper tissue but is still just found in the uterus. It has not spread to lymph nodes or other parts of the body (T1, N0, M0). This stage may be described in more detail (see below).
Stage Ia: T1a, N0, M0
Stage Ia1: T1a1, N0, M0
Stage Ia2: T1a2, N0, M0
Stage Ib: T1b, N0, M0
Stage Ib1: T1b1, N0, M0
Stage Ib2: T1b2, N0, M0
Stage II: The cancer has spread beyond the cervix to nearby areas, such as the vagina or tissue near the cervix, but it is still inside the pelvic area. It has not spread to lymph nodes or other parts of the body (T2, N0, M0). This stage may be described in more detail (see below).
Stage IIa: T2a, N0, M0
Stage IIa1: T2a1, N0, M0
Stage IIa2: T2a2, N0, M0
Stage IIb: T2b, N0, M0
Stage III: The cancer has spread outside of the cervix and vagina but not to the lymph nodes or other parts of the body (T3, N0, M0).
Stage IIIa: The cancer has spread to the lower part of the vagina but not to other parts of the body (T3a, N0, M0).
Stage IIIb: The cancer may have spread as far as the pelvic wall and to lymph nodes but not to other parts of the body (T1, T2, or T3a; N1, M0). If it has spread to the pelvic wall, it is called stage IIIb regardless of whether there is cancer in the lymph nodes (T3b, any N, M0).
Stage IVa: The cancer has spread to the bladder or rectum and may or may not have spread to the lymph nodes, but it has not spread to other parts of the body (T4, any N, M0).
Stage IVb: The cancer has spread to other parts of the body (any T, any N, M1).
Recurrent. Recurrent cancer is cancer that comes back after treatment. It may come back in the cervix or in another place. If there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net.