What does the stage of cancer mean?

The stage of a cancer is how much cancer there is and how far it has spread in your body. Your healthcare provider uses exams and tests to find out the size of the tumor and where it is. Scans can also show if the cancer has grown into nearby areas, and if it has spread to other parts of your body. The stage is one of the most important things to know when deciding how to treat the cancer.

The TNM system for oral cancer

The most commonly used system to stage oral cancers is the TNM system from the American Joint Committee on Cancer. Ask your healthcare provider to explain the stage of your cancer to you in a way you can understand.

The first step in staging is to find the value for each part of the TNM system. Here's what the letters stand for in the TNM system:

• T tells how large the main (or primary)  tumor is and how far it has spread into nearby tissues. The tumor size is measured in centimeters (cm). How deep the tumor has invaded tissue is called depth of invasion. (This is not the thickness of the tumor.) It is measured in millimeters (mm).

• N tells if the lymph  nodes near the primary tumor have cancer in them. Extranodal extension positive (ENE +) means cancer has spread through the lymph node into surrounding tissues. ENE negative (ENE -) has not spread outside the lymph node.

• M tells if the cancer has spread ( metastasized) to organs in other parts of the body, such as the lungs.

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 provider 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 cancer in the lymph nodes (N0).

 What are the stage groupings of oral cancer?

The T, N, and M values from the TNM system are used to put these cancers into stage groupings. The groupings give an overall description of your cancer. A stage grouping is listed as a Roman numeral and can have a value of I (1), II (2), III (3), or IV (4). The higher the number, the more advanced the cancer is.

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

Stage 0 (or carcinoma in situ) . The cancer is only in the top layer of the lining of the oral cavity where it first started. It has not spread to nearby lymph nodes or organs in other parts of the body.

Stage I.  The cancer is no more than 2 cm (centimeters) across. The deepest point of invasion into nearby tissues is no more than 5 mm. It has not spread to nearby lymph nodes or organs in other parts of the body. (T1 N0 M0)

Stage II. The cancer has not spread to lymph nodes or organs in other parts of the body (T2 N0 M0). One of the following is true:

• The cancer is no more than 2 cm across. The deepest point of invasion is more than 5 mm.

• The cancer is more than 2 cm but not larger than 4 cm across. The deepest point of invasion is not more than 10 mm.

Stage III. The cancer has not spread to organs in other parts of the body, and one of the following is true:

• The cancer is more than 2 cm across but not more than 4 cm. with the deepest point of invasion more than 10 mm. Or the cancer is more than 4 cm across and the deepest point of invasion is not more than 10 mm. The cancer has not spread to lymph nodes (T3, N0 M0).

• The cancer is any size and depth of invasion but has not grown into nearby structures. It has spread to 1 lymph node on the same side of the neck as the primary tumor. The lymph node is no more than 3 cm across and the cancer has not spread to the outside of it (ENE -). This stage grouping is designated as T1-T3, N1 M0.

Stage IV. This stage is divided into three subgroups: 

• Stage IVA. (T1-T3 N2 M0 or T4a N0-N2 M0) The cancer is any size and depth in invasion and may have spread into nearby structures, such as the bones of the face or jaw, muscles deep in the tongue, the maxillary sinus (the sinuses in the cheeks on both sides of the nose), or the skin on the face. It has not spread to organs in other parts of the body and one of the following is true related to the lymph node status:

  • It has not spread to nearby lymph nodes, or it has spread to 1 lymph node on the same side of the neck as the primary tumor. The node is no more than 3 cm across and the cancer has not spread to the outside of it (ENE -).

  • The cancer has spread to 1 lymph node on the same side of the neck as the primary tumor. The node is more than 3 cm but less than 6 cm across and the cancer has not spread to the outside of it (ENE -).

  • It has spread to more than 1 lymph node on the same side of the neck as the primary tumor. None of the nodes are more than 6 cm across and the cancer has not spread to the outside of any of them (ENE -).

  • The cancer has spread to at least 1 lymph node on the opposite side of the neck as the primary tumor or to lymph nodes on both sides of the neck. None of the nodes are more than 6 cm across, and the cancer has not spread to the outside of any of them (ENE -).

• Stage IVB.  (Any T N3 M0 or T4b Any N M0) The cancer is any size and may have spread into nearby tissues and structures, such as the bones of the face or jaw, muscles deep in the tongue, the maxillary sinus (the sinuses in the cheeks on both sides of the nose), or the skin on the face. It has not spread to organs in other parts of the body and 1 of the following is true:

  • There is spread to lymph nodes in one of these ways:

    • The cancer has spread to 1 lymph node that's more than 6 cm across, but the cancer has not spread to the outside of it (ENE -).

    • It has spread to 1 lymph node that's more than 3 cm across and has clearly grown outside the node (ENE +).

    • It has spread to more than 1 lymph node on the same side of the neck as the primary tumor, a node on the opposite side of the neck, or to nodes on both sides of the neck and has clearly grown outside of at least 1 node (ENE +).

    • The cancer has spread to 1 lymph node on the opposite side of the neck as the primary tumor. The node is no more than 3 cm across and the cancer has clearly grown outside the node.

  • The cancer is growing into the base of the skull or other nearby bones, or it's wrapped around the carotid artery. It may or may not have spread to nearby lymph nodes. be any size, and located anywhere in the neck and may or may not be ENE +.

• Stage IVC.  (Any T Any N M1) The cancer is any size and may have spread into nearby tissues and structures. It may or may not have spread to nearby lymph nodes, be any size, and be located anywhere in the neck. It may or may not be ENE +. It has spread to organs in other parts of the body, such as the lungs, bones, or liver.

Talking with your healthcare provider

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