Oral Cavity (Mouth) and Oropharyngeal (Throat) Cancer

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Oral Cavity and Oropharyngeal Cancer Stages

If you are diagnosed with oral cavity (mouth) or oropharyngeal (throat) cancer, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer's stage when talking about survival statistics.

Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

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How are oral cavity and oropharyngeal cancers staged?

Each stage of an oral cavity or oropharyngeal cancer is assigned a number. The earliest is stage 0, also known as carcinoma in situ (CIS). Other stages range from I through IV. Some stages are further divided using the letters A and B.

As a rule:

  • The lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more.
  • Within each numbered stage (I-IV), an earlier letter means a lower stage.

Stage grouping

The staging system most often used for oral cavity or oropharyngeal cancers is the American Joint Committee on Cancer (AJCC) TNM system. The staging system in the tables below is based on the most recent AJCC system, effective January 2018.

This system uses 3 key pieces of information:

  • Extent of the tumor (T): How large is the main (primary) tumor? Which tissues of the oral cavity or oropharynx has it spread to, if any?
  • Spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes? If so, how many? Are they on the same side as where the cancer started, and how large are they?
  • Spread (metastasis) to distant sites (M): Has the cancer spread to distant organs such as the lungs?

Numbers or letters after T, N, and M provide more details about each of these factors. 

Once the T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more information, see Cancer Staging.

Pathological vs. clinical stage

Pathological stage (surgical stage): The staging systems shown below use the pathologic stage, also called the surgical stage. This is determined by examining the tissue removed during an operation.

Clinical stage: Sometimes, if surgery isn't possible right away or at all, the cancer will be given a clinical stage instead. This is based on the results of a physical exam, endoscopy exam, biopsy, and imaging tests. The clinical stage will be used to help plan treatment. However, sometimes the cancer has spread further than the clinical stage estimates, and it may not predict a person’s outlook as accurately as a pathologic stage. Clinical stage is not shown in the tables below.

Cancer staging can be complex. If you have any questions about your cancer’s stage and what it might mean for you, ask your doctor to explain it in a way you understand.

Stages of oral cavity cancer (including the lips)

Oral cavity cancer is stage 0 if:

  • The cancer is still within the epithelium (the top layer of cells lining the oral cavity) and has not yet grown into deeper layers.
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant parts of the body (M0).

This stage is also known as carcinoma in situ (Tis).

Oral cavity cancer is stage I if:

  • The cancer is 2 cm* or smaller and depth of invasion (DOI) is 5mm or less (T1).
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant parts of the body (M0).

*2 cm = about ¾ inch

Oral cavity cancer is stage II if:

  • The cancer is 2 cm* or smaller and depth of invasion (DOI) is greater than 5mm or the cancer is larger than 2 cm but no larger than 4 cm and DOI is 10mm or less (T2). 
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant parts of the body (M0).

*2 cm = about ¾ inch; 4 cm = about 1½ inch

Stage grouping: T3, N0 or N1, M0

  • The cancer is larger than 2 cm* but no larger than 4 cm and depth of invasion (DOI) is greater than 10mm or the cancer is larger than 4 cm and DOI is 10mm or less (T3).
  • It has not spread to nearby lymph nodes (N0) or it has spread to a single lymph node on the same side as the cancer, is 3 cm or smaller, and has not grown outside the lymph node (N1). 
  • It has not spread to distant parts of the body (M0).

*2 cm = about ¾ inch; 3 cm = about 1¼ inch; 4 cm = about 1½ inch

Stage grouping: T1 or T2, N1, M0

  • The cancer is 2 cm* or smaller and depth of invasion (DOI) is 5mm or less (T1) or the cancer is 2 cm or smaller and DOI is greater than 5mm or it is larger than 2 cm but no larger than 4 cm and DOI is 10mm or less (T2). 
  • It has spread to a single lymph node on the same side as the cancer, is 3 cm or smaller, and has not grown outside the lymph node (N1).
  • It has not spread to distant parts of the body (M0).

Stage grouping: T4a, N0, N1, or N2, M0

  • The cancer is larger than 4 cm* and depth of invasion (DOI) is greater than 10mm or the cancer is any size and is growing into nearby structures such as bone, sinus, or skin of the face (T4a).
  • The cancer has not spread to nearby lymph nodes (N0) or it has spread to a single lymph node on the same side as the cancer, is 3 cm or smaller, and has not grown outside the lymph node (N1) or it has spread to a single lymph node on the same side of the cancer, is 3 cm or smaller, and has grown outside the lymph node, or it has spread to lymph node(s) on the same or both sides of the cancer, is larger than 3 cm but less than 6 cm, and has not grown outside the lymph nodes (N2).
  • The cancer has not spread to distant parts of the body (M0).

*2 cm = about ¾ inch; 3 cm = about 1¼ inch; 4 cm = about 1½ inch

Stage grouping: T1, T2, or T3, N2, M0

  • The cancer is 2 cm* or smaller and depth of invasion (DOI) is 5mm or less (T1) or the cancer is 2 cm or smaller and DOI is greater than 5mm or the cancer is larger than 2 cm but no larger than 4 cm and DOI is 10mm or less (T2) or the cancer is larger than 2 cm but no larger than 4 cm and DOI is greater than 10mm or the tumor is larger than 4 cm and DOI is 10mm or less (T3).
  • It has spread to a single lymph node on the same side of the cancer, is 3 cm or smaller, and has grown outside the lymph node or it has spread to lymph node(s) on the same or both sides of the cancer, is larger than 3 cm but less than 6 cm, and has not grown outside the lymph nodes (N2). 
  • It has not spread to distant organs (M0).

Stage grouping: any T, N3, M0

  • The cancer is any size and may have grown into nearby soft tissues or structures (any T).
  • The cancer has spread to a lymph node that is larger than 6cm and has not grown outside the lymph nodes (N3a) or it has spread to a single lymph node on the same side as the cancer, is larger than 3 cm, and has grown outside the lymph node (N3b) or it has spread to multiple lymph nodes and has grown outside the lymph nodes (N3b) or it has spread to a single lymph node on the opposite side of the cancer and has grown outside the lymph node (N3b).
  • It has not spread to distant organs (M0).

*2 cm = about ¾ inch; 3 cm = about 1¼ inch; 4 cm = about 1½ inch

Stage grouping: T4b, any N, M0

  • The cancer is any size and is growing into nearby structures such as the base of the skull or other bones nearby, or it surrounds the internal carotid artery. This is known as very advanced local disease (T4b).
  • It might or might not have spread to nearby lymph nodes (any N).
  • It has not spread to distant organs (M0).

  • The cancer is any size and may have grown into nearby soft tissues or structures (any T).
  • It might or might not have spread to nearby lymph nodes (any N).
  • It has spread to distant sites such as the lungs (M1).

Other staging categories you might see

  • TX: Main tumor cannot be assessed due to lack of information.
  • T0: No evidence of a primary tumor.
  • NX: Regional lymph nodes cannot be assessed due to lack of information.

Stages of oropharyngeal cancer

Oropharyngeal cancers that contain HPV DNA (called p16-positive) tend to have a better outlook than those without HPV (p16-negative).

Separate staging systems are used for these, because p16-positive oropharyngeal cancers have a better prognosis than p16-negative cancers.

p16 (HPV)-negative oropharyngeal cancer

  • The cancer is still within the epithelium (the top layer of cells lining the oral cavity and oropharynx) and has not yet grown into deeper layers (Tis, carcinoma in situ). 
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant sites (M0).

  • The cancer is 2 cm* or smaller.
  • It is not growing into nearby tissues (T1).
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant sites (M0).

*2 cm = about ¾ inch

  • The cancer is larger than 2 cm* but no larger than 4 cm.
  • It is not growing into nearby tissues (T2).
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant sites (M0).

*2 cm = about ¾ inch; 4 cm = about 1½ inch

Stage grouping: T3, N0, M0

  • The cancer is larger than 4 cm* or has grown into the epiglottis (the base of the tongue) (T3).
  • It has not spread to nearby lymph nodes (N0).
  • It has not spread to distant sites (M0).

*3 cm = about 1¼ inch; 4 cm = about 1½ inch

Stage grouping: T1, T2, or T3, N1, M0

  • The cancer is any size or has grown into the epiglottis (the base of the tongue) (T1 to T3). 
  • It has spread to a single lymph node on the same side of the cancer, is 3 cm or smaller, and has not grown outside the lymph node (N1).
  • It has not spread to distant sites (M0).

Stage grouping: T4a, N0, N1, M0

  • The cancer is any size and has grown into nearby structures such as the larynx (voice box), the tongue muscle, or bones such as the medial pterygoid, the hard palate, or the jaw. This is known as moderately advanced local disease (T4a). 
  • The cancer has not spread to nearby lymph nodes (N0) or it has spread to a single lymph node on the same side as the cancer, is 3 cm* or smaller, and has not grown outside the lymph node (N1).
  • It has not spread to distant sites (M0).

*3 cm = about 1¼ inch

Stage grouping: T1, T2, T3, or T4a, N2, M0

  • The cancer is any size or has grown into nearby structures (T0 to T4a). 
  • The cancer has spread to a single lymph node on the same side as the cancer, is 3 cm or smaller, and has grown outside the lymph node or it has spread to lymph node(s) on the same or both sides of the cancer, is larger than 3 cm but less than 6 cm, and has not grown outside the lymph nodes (N2). 
  • It has not spread to distant organs (M0).

Stage grouping: any T, N3, M0

  • The cancer is any size and may have grown into nearby soft tissues or structures (any T).
  • The cancer has spread to a lymph node that is larger than 6cm and has not grown outside the lymph nodes (N3a) or it has spread to a single lymph node on the same side of the cancer, is larger than 3 cm*, and has grown outside the lymph node (N3b) or it has spread to multiple lymph nodes and has grown outside the lymph nodes (N3b) or it has spread to a single lymph node on the opposite side of the cancer and has grown outside the lymph node (N3b).
  • It has not spread to distant organs (M0).

3 cm = about 1¼ inch

Stage grouping: T4b, any N, M0

  • The cancer is any size and is growing into nearby structures such as the base of the skull or other bones nearby, or it surrounds the carotid artery. This is known as very advanced local disease (T4b).
  • It might or might not have spread to nearby lymph nodes (any N).
  • It has not spread to distant organs (M0).

  • The cancer is any size and may have grown into nearby soft tissues or structures (any T).
  • It might or might not have spread to nearby lymph nodes (any N).
  • It has spread to distant sites such as the lungs (M1).

p16 (HPV)-positive oropharyngeal cancer

  • The cancer is no larger than 4 cm* (T0 to T2).
  • The cancer has not spread to nearby lymph nodes (N0) or it has spread to no more than 4 lymph nodes (N1).
  • It has not spread to distant sites (M0).

*4 cm = about 1½ inches

Stage grouping: T0, T1 or T2, N2, M0

  • The cancer is no larger than 4 cm* (T0 to T2).
  • It has spread to more than 4 lymph nodes (N2).
  • It has not spread to distant sites (M0).

*4 cm = about 1½ inches

Stage grouping: T3 or T4, N0 or N1, M0

  • The cancer is larger than 4 cm (T3) or it is growing into the epiglottis (the base of the tongue) (T3) or it is growing into the larynx (voice box), the tongue muscle, or bones such as the medial pterygoid plate, the hard palate, or the jaw (T4).
  • It has not spread to nearby lymph nodes (N0) or it has spread to no more than 4 lymph nodes (N1).
  • It has not spread to distant sites (M0).

  • The cancer is larger than 4 cm* (T3) or it is growing into the epiglottis (the base of the tongue) (T3) or it is growing into the larynx (voice box), the tongue muscle, or bones such as the medial pterygoid plate, the hard palate, or the jaw (T4).
  • It has spread to more than 4 lymph nodes (N2).
  • It has not spread to distant sites (M0).

*4 cm = about 1½ inches

  • The cancer is any size and may have grown into nearby structures (any T).
  • It might or might not have spread to nearby lymph nodes (any N).
  • It has spread to distant sites such as the lungs or bones (M1).

Other staging categories you might see

  • TX: Main tumor cannot be assessed due to lack of information.
  • T0: No evidence of a primary tumor.
  • NX: Regional lymph nodes cannot be assessed due to lack of information.

Recurrent (relapsed) cancer

This is not an actual stage in the TNM system. Recurrent (relapsed) cancer means that the cancer has come back (recurred) after treatment.

Recurrent oral cavity or oropharyngeal cancer may return in:

  • The mouth or throat (local recurrence)
  • Nearby lymph nodes (regional recurrence)
  • Another part of the body, such as the lungs (distant recurrence)

Talk to your doctor if you have any questions about the stage of your cancer or how it affects your treatment.

side by side logos for American Cancer Society and American Society of Clinical Oncology

Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).

American Joint Committee on Cancer. Lip and Oral Cavity. In: AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer; 2017:79.

American Joint Committee on Cancer. HPV-Mediated (p16+) Oropharyngeal Cancer. In: AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer; 2017:113.

American Joint Committee on Cancer. Oropharynx (p16-) and Hypopharynx. In: AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer; 2017:123.

Last Revised: March 23, 2026

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.

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