Oral and Oropharyngeal Cancer: Stages and Grades

Approved by the Cancer.Net Editorial Board, 09/2017

ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread. This is called the stage. Use the menu to see other pages.

Staging is a way of describing where a cancer is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostic tests to find out the cancer’s stage, so staging may not be complete until all 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, which is the chance of recovery. There are different stage descriptions for different types of cancer.

TNM staging system

One tool that doctors use to describe the stage is the TNM system. Doctors use the results from diagnostic tests and scans to answer these questions:

  • Tumor (T): How large is the primary tumor? Where is it located?

  • Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?

  • Metastasis (M): Has the cancer metastasized to other parts of the body? If so, where and how much?

The TNM system differs depending whether the diagnosis is oral cancer, oropharyngeal cancer, or HPV-related oropharyngeal cancer.

The results of the TNM system are combined to determine the stage of cancer for each person. There are 4 or 5 stages, depending on the diagnosis. Stage 0 (zero) is only used for non-HPV-related oropharyngeal cancer. Stages I through IV (1 through 4) are used for all 3 types of oral and oropharyngeal cancer. The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.

Here are more details on each part of the TNM system for oral and oropharyngeal cancer.

Tumor (T)

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 also divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below.

Oral cavity

TX: The primary tumor cannot be evaluated.

Tis: Describes a stage called carcinoma (cancer) in situ. This is a very early cancer where cancer cells are found only in 1 layer of tissue.

T1: The tumor is 2 centimeters (cm) or less at its greatest dimension. The tumor has invaded nearby tissues to a depth of 5 millimeters (mm) or less; this is called depth of invasion.

T2: The tumor is 2 cm or smaller, and the depth of invasion is between 5 and 10 mm. Or, the tumor is larger than 2 cm but not larger than 4 cm, and the depth of invasion is 10 mm or less.

T3: The tumor is larger than 4 cm, or it is any tumor with a depth of invasion greater than 10 mm.

T4: This is moderately advanced or very advanced local disease.

  • T4a (lip): The tumor began on the lip but has invaded bone or spread to the inferior alveolar nerve in the mouth, the floor of the mouth, or the skin of the face.

  • T4a (oral cavity): The tumor has invaded nearby structures in the mouth, such as the jaw, sinuses, or skin of the face.

  • T4b: The tumor has invaded the muscles and bones that form the mouth or the base of the skull, and/or it encases the internal arteries.

Oropharynx

TX: The primary tumor cannot be evaluated.

Tis: Describes a stage called carcinoma (cancer) in situ. This is a very early cancer where cancer cells are found only in 1 layer of tissue.

T1: The tumor is 2 centimeters (cm) or smaller at its greatest dimension.

T2: The tumor is larger than 2 cm but not larger than 4 cm.

T3: The tumor is larger than 4 cm or has spread to the epiglottis, which is the flap of cartilage that diverts food into the esophagus.

T4a: The tumor has invaded the larynx, muscle of the tongue, muscles in the jaw, roof of the mouth, or jawbone.

T4b: The tumor has invaded muscles and bones in the region of the mouth; the nasopharynx, which is the air passageway at the upper part of the throat behind the nose; or the base of the skull, or the tumor encases the carotid artery.

HPV-related oropharyngeal cancer

T0 (T plus zero): No tumor can be found.

T1: The tumor is 2 centimeters (cm) or smaller at its greatest dimension.

T2: The tumor is larger than 2 cm but not larger than 4 cm.

T3: The tumor is larger than 4 cm or has spread to the epiglottis, which is the flap of cartilage that diverts food into the esophagus.

T4: The tumor has invaded the larynx, muscle of the tongue, muscles in the jaw, roof of the mouth, or jawbone.

Node (N)

The “N” in the TNM staging system stands for lymph nodes. These tiny, bean-shaped organs help fight infection. Lymph nodes near where the cancer started are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. There are many lymph nodes in the head and neck area. Careful assessment of lymph nodes is an important part of staging.

When cancer has spread through a lymph node and into the tissues directly surrounding it, it is called extranodal extension (ENE). Knowing whether ENE is present plays an important role in the evaluation of lymph nodes in oral and oropharyngeal cancers that are not related to HPV.

There are 2 methods of categorizing N in the TNM system: clinical and pathological. Clinical N is used for patients who have not received a neck dissection (see “Surgery” in Treatment Options). Pathological N is used for those who have had a lymph node dissection.

Oral cavity and oropharynx—clinical

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): There is no evidence of cancer in the regional lymph nodes.

N1: The cancer has spread to a single lymph node on the same side as the primary tumor, and the cancer found in the node is 3 cm or smaller. There is no ENE.

N2a: Cancer has spread to a single lymph node on the same side as the primary tumor and is larger than 3 cm but not larger than 6 cm. There is no ENE.

N2b: Cancer has spread to more than 1 lymph node on the same side as the primary tumor, and none measures larger than 6 cm. There is no ENE.

N2c: Cancer has spread to more than 1 lymph node on either side of the body, and none measures larger than 6 cm. There is no ENE.

N3a: The cancer is found in a lymph node and is larger than 6 cm. There is no ENE.

N3b: There is ENE in any lymph node.

Oral cavity and oropharynx—pathological

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): There is no evidence of cancer in the regional lymph nodes.

N1: The cancer has spread to a single lymph node on the same side as the primary tumor, and the cancer found in the node is 3 cm or smaller. There is no ENE.

N2a: Cancer has spread to 1 lymph node and is 3 cm or smaller, but there is ENE. Or, cancer has spread to a single lymph node on the same side as the primary tumor and is larger than 3 cm but not larger than 6 cm, and there is no ENE.

N2b: Cancer has spread to more than 1 lymph node on the same side as the primary tumor, and none measures larger than 6 cm. There is no ENE.

N2c: Cancer has spread to more than 1 lymph node on either side of the body, and none measures larger than 6 cm. There is no ENE.

N3a: The cancer is found in a lymph node and is larger than 6 cm. There is no ENE.

N3b: There is ENE in a single lymph node on the same side as the primary tumor, and it is larger than 3 cm. Or, cancer has spread to many lymph nodes, and at least 1 has ENE. Or, there is ENE in a single lymph node on the opposite side of the primary tumor that is 3 cm or smaller.

HPV-related oropharyngeal cancer—clinical

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): There is no evidence of cancer in the regional lymph nodes.

N1: The cancer has spread to 1 or more lymph nodes on the same side as the primary tumor, and the cancer found in the node is 6 cm or smaller.

N2: Cancer has spread to 1 or more lymph nodes on either side of the body, and none is larger than 6 cm.

N3: The cancer is found in a lymph node and is larger than 6 cm.

HPV-related oropharyngeal cancer—pathological

NX: The regional lymph nodes cannot be evaluated.

pN0 (N plus zero): There is no evidence of cancer in the regional lymph nodes.

pN1: The cancer has spread to 1 to 4 lymph nodes.

pN2: Cancer has spread to more than 4 lymph nodes.

Metastasis (M)

The "M" in the TNM system indicates whether the cancer has spread to other parts of the body, called distant metastasis.

M0 (M plus zero): Cancer has not spread to other parts of the body.

M1: Cancer has spread to other parts of the body.

Cancer stage grouping

Doctors combine the T, N, and M information to say what stage the cancer is.

Oral cavity

Stage 1: The tumor is 2 centimeters (cm) or smaller, and the depth of invasion is 5 millimeters (mm) or less. The cancer has not spread to lymph nodes or other parts of the body (T1, N0, M0).

Stage II: The tumor is 2 cm or smaller, and the depth of invasion is between 5 and 10 mm. Or, the tumor is larger than 2 cm but not larger than 4 cm, and the depth of invasion is 10 mm or less. The cancer has not spread to lymph nodes or other parts of the body (T2, N0, M0).

Stage III: Either of the following applies:

  • The tumor is larger than 4 cm, or it is any tumor with a depth of invasion greater than 10 mm. The cancer has not spread to lymph nodes or other parts of the body (T3, N0, M0).

  • The tumor is any size, but it has not invaded nearby structures of the oral cavity. There is cancer in a single lymph node on the same side as the primary tumor, and the cancer is 3 cm or smaller. There is no ENE. Cancer has not spread to other parts of the body (T1–T3, N1, M0).

Stage IVA: Either of the following applies:

  • The tumor has invaded nearby structures in the mouth, such as the jaw, sinuses, or skin of the face. If cancer has spread to a lymph node, it is to only 1 node on the same side as the primary tumor, and the cancer is 3 cm or smaller, with no ENE. Cancer has not spread to other parts of the body (T4a, N0 or N1, M0).

  • The tumor may be small or it may have invaded nearby structures. Cancer has spread to 1 or more lymph nodes, but none is larger than 6 cm. There is no ENE. Cancer has not spread to other parts of the body (T1–T4a, N2, M0).

Stage IVB: Either of the following applies:

  • The tumor is any size. The cancer is found in a lymph node and is larger than 6 cm, but there is no ENE; or there is ENE in any lymph node. Cancer has not spread to other parts of the body (any T, N3, M0).

  • The tumor has invaded the muscles and bones that form the mouth or the base of the skull, and/or it encases the internal arteries. The cancer may involve the lymph nodes, but it has not spread to other parts of the body (T4b, any N, M0).

Stage IVC: Cancer has spread to other parts of the body (any T, any N, M1).

Oropharynx

Stage 0: There is carcinoma in situ, with no spread to lymph nodes or other parts of the body (Tis, N0, M0).

Stage I: The tumor is 2 cm or less in size, but cancer has not spread to lymph nodes or other parts of the body (T1, N0, M0).

Stage II: The tumor is between 2 cm and 4 cm, but cancer has not spread to lymph nodes or other parts of the body (T2, N0, M0).

Stage III: Either of the following applies:

  • The tumor is larger than 4 cm or has spread to the epiglottis, but the cancer has not spread to lymph nodes or other parts of the body (T3, N0, M0).

  • The tumor has not invaded nearby tissues, except the epiglottis. Cancer is in 1 lymph node on the same side as the primary tumor, and it is 3 cm or smaller, with no ENE. Cancer has not spread to other parts of the body (T1–T3, N1, M0).

Stage IVA: Either of the following applies:

  • The tumor has invaded the larynx, muscle of the tongue, muscles in the jaw, roof of the mouth, or jawbone. Cancer may have spread to 1 lymph node, but it has not spread to other parts of the body (T4a, N0 or N1, M0).

  • The tumor may be small or it may have invaded nearby structures, like the larynx, muscles of the tongue or jaw, roof of the mouth, or jawbone. Cancer has spread to 1 or more lymph nodes, but none is larger than 6 cm. There is no ENE. Cancer has not spread to other parts of the body (T1–T4a, N2, M0).

Stage IVB: Either of the following applies:

  • The tumor is any size. The cancer is found in a lymph node and is larger than 6 cm, but there is no ENE; or there is ENE in any lymph node. Cancer has not spread to other parts of the body (any T, N3, M0).

  • The tumor has invaded muscles and bones in the region of the mouth; the nasopharynx, which is the air passageway at the upper part of the throat behind the nose; or the base of the skull, or the tumor encases the carotid artery. Lymph nodes may or may not be involved. Cancer has not spread to other parts of the body (T4b, any N, M0).

Stage IVC: Cancer has spread to other parts of the body (any T, any N, M1).

HPV-related oropharyngeal cancer

The stage groups for HPV-related oropharyngeal cancer differ depending on whether the lymph nodes have been assessed clinically or pathologically.

Clinical stage groups

Stage I: The tumor is 4 cm or smaller. If cancer has spread to lymph nodes, none of the cancer is larger than 6 cm and it only affects lymph nodes on the same side of the body as the primary tumor. Cancer has not spread to other parts of the body (T0–T2, N0 or N1, M0).

Stage II: Either of the following applies:

  • The tumor is 4 cm or smaller. Cancer has spread to 1 or more lymph nodes on either side of the body, and none is larger than 6 cm. Cancer has not spread to other parts of the body (T0–T2, N2, M0).

  • The tumor is larger than 4 cm or has spread to the epiglottis. If lymph nodes are involved, none of the cancer is larger than 6 cm. Cancer has not spread to other parts of the body (T3, N0–N2, M0).

Stage III: Either of the following applies:

  • The tumor is any size. Cancer has spread to lymph nodes, and it is larger than 6 cm. There is no spread to other parts of the body (any T, N3, M0).

  • The tumor has invaded the larynx, muscle of the tongue, muscles in the jaw, roof of the mouth, or jawbone. Lymph nodes may or may not be involved. There is no spread to other parts of the body (T4, any N, M0).

Stage IV: Cancer has spread to other parts of the body (any T, any N, M1).

Pathological stage groups

Stage I: The tumor is 4 cm or smaller. The cancer involves 4 or fewer lymph nodes. Cancer has not spread to other parts of the body (T0–T2, pN0­ or pN1, M0).

Stage II: Either of the following applies:

  • The tumor is 4 cm or smaller. Cancer has spread to more than 4 lymph nodes. There is no spread to other parts of the body (T0–T2, pN2, M0).

  • The tumor is larger than 4 cm or it invades nearby structures. The cancer involves 4 or fewer lymph nodes. Cancer has not spread to other parts of the body (T3 or T4, pN0 or pN1, M0).

Stage III: The tumor is larger than 4 cm or it invades nearby structures. Cancer has spread to more than 4 lymph nodes. There is no spread to other parts of the body (T3 or T4, pN2, M0).

Stage IV: Cancer has spread to other parts of the body (any T, any pN, M1).

Recurrent: Recurrent cancer is cancer that has come back after treatment. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Grade (G)

Doctors also describe oral and oropharyngeal cancer by its grade (G), which describes how much cancer cells look like healthy cells when viewed under a microscope. HPV-related oropharyngeal cancer does not have a grading system. The doctor compares the cancerous tissue with healthy tissue. Healthy tissue usually contains many different types of cells grouped together. If the cancer looks similar to healthy tissue and contains different cell groupings, it is called differentiated or a low-grade tumor. If the cancerous tissue looks very different from healthy tissue, it is called poorly differentiated or a high-grade tumor. The cancer’s grade can help the doctor predict how quickly the cancer will spread. In general, the lower the tumor’s grade, the better the prognosis.

GX: The grade cannot be evaluated.

G1: The cells look more like normal tissue and are well differentiated.

G2: The cells are only moderately differentiated.

G3 and G4: The cells don’t resemble normal tissue and are poorly differentiated.

Used with permission of the American College of Surgeons, Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer International Publishing.

Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Treatment Options. You may use the menu to choose a different section to read in this guide.