| Primary tumor (T) | |||
| T category | T criteria | ||
| TX | Primary tumor cannot be assessed | ||
| Tis | Carcinoma in situ | ||
| T1 | Tumor ≤2 cm with depth of invasion (DOI)* ≤5 mm | ||
| T2 | Tumor ≤2 cm, with DOI* >5 mm and ≤10 mm; or Tumor >2 cm and ≤4 cm, with DOI* ≤10 mm | ||
| T3 | Tumor >2 cm and ≤4 cm with DOI* >10 mm; or Tumor >4 cm with DOI* ≤10 mm | ||
| T4 | Moderately advanced or very advanced local disease | ||
| T4a | Moderately advanced local disease. Tumor >4 cm with DOI* >10 mm; or Tumor invades adjacent structures only (eg, through cortical bone of the mandible or maxilla, or involves the maxillary sinus or skin of the face). NOTE: Superficial erosion of bone/tooth socket (alone) by a gingival primary is not sufficient to classify a tumor as T4. | ||
| T4b | Very advanced local disease. Tumor invades masticator space, pterygoid plates, or skull base and/or encases the internal carotid artery. | ||
| * DOI is depth of invasion and not tumor thickness. | |||
| Regional lymph nodes (N) | |||
| Clinical N (cN) | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis | ||
| N1 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension ENE(–) | ||
| N2 | Metastasis in a single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–); or Metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(–); or In bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, and ENE(–) | ||
| N2a | Metastasis in a single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension, and ENE(–) | ||
| N2b | Metastases in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension, and ENE(–) | ||
| N2c | Metastases in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, and ENE(–) | ||
| N3 | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–); or Metastasis in any node(s) and clinically overt ENE(+) | ||
| N3a | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–) | ||
| N3b | Metastasis in any node(s) and clinically overt ENE(+) | ||
| NOTE: A designation of "U" or "L" may be used for any N category to indicate metastasis above the lower border of the cricoid (U) or below the lower border of the cricoid (L). Similarly, clinical and pathological ENE should be recorded as ENE(–) or ENE(+). | |||
| Pathological N (pN) | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis | ||
| N1 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(–) | ||
| N2 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(+); or Larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–); or Metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(–); or In bilateral or contralateral lymph node(s), none larger than 6 cm in greatest dimension, ENE(–) | ||
| N2a | Metastasis in single ipsilateral node 3 cm or smaller in greatest dimension and ENE(+); or A single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–) | ||
| N2b | Metastases in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(–) | ||
| N2c | Metastases in bilateral or contralateral lymph node(s), none larger than 6 cm in greatest dimension and ENE(–) | ||
| N3 | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–); or Metastasis in a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or Multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or A single contralateral node of any size and ENE(+) | ||
| N3a | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–) | ||
| N3b | Metastasis in a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or Multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or A single contralateral node of any size and ENE(+) | ||
| NOTE: A designation of "U" or "L" may be used for any N category to indicate metastasis above the lower border of the cricoid (U) or below the lower border of the cricoid (L). Similarly, clinical and pathological ENE should be recorded as ENE(–) or ENE(+). | |||
| Distant metastasis (M) | |||
| M category | M criteria | ||
| M0 | No distant metastasis | ||
| M1 | Distant metastasis | ||
| Prognostic stage groups | |||
| When T is... | And N is... | And M is... | Then the stage group is... |
| Tis | N0 | M0 | 0 |
| T1 | N0 | M0 | I |
| T2 | N0 | M0 | II |
| T3 | N0 | M0 | III |
| T1, T2, T3 | N1 | M0 | III |
| T4a | N0, N1 | M0 | IVA |
| T1, T2, T3, T4a | N2 | M0 | IVA |
| Any T | N3 | M0 | IVB |
| T4b | Any N | M0 | IVB |
| Any T | Any N | M1 | IVC |
