This article is mainly intedend for use by medical professionals.
The recently released 8th edition of the American Joint Committee on Cancer (AJCC) Staging Manual, Head and Neck Section, introduces significant modifications from the prior 7th edition.
In this article, we discuss the changes in the 8th edition of AJCC staging manual for oral cavity cancers.
T Staging
For T staging of the oral cavity cancers, T4a and T4b are added in new TNM staging.
T4a is moderately advanced local disease: lip, tumor invades through cortical bone or involves the inferior alveolar nerve, floor of the mouth or skin of the face (i.e. chin or nose).
T4b is a very advanced local disease, tumor invades masticator space and pterygoid plates, or skull base encases the internal carotid artery.
| Primary Tumor (T) | ||
| T Category | T Criteria | |
| Tx | Primary tumor cannot be assessed. | |
| Tis | Carcinoma in situ | |
| T1 | Tumor ≤2 cm, ≤5 mm depth of invasion (DOI). DOI is the depth of invasion and not tumor thickness. |
|
| T2 | Tumor ≤2 cm, DOI >5 mm and ≤10 mm; or Tumor >2 cm but ≤4 cm, and ≤10 mm DOI |
|
| T3 | Tumor >4 cm; or Any tumor >10 mm DOI |
|
| T4 | T4a | Moderately advanced local disease |
| LIP: Tumor invades through cortical bone or involves the inferior alveolar nerve, the floor of mouth, or skin of the face (ie, chin or nose). | ||
| ORAL CAVITY: 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. | ||
N Staging
In the new edition of TNM Staging for oral cavity cancers, there are now separate classifications for clinical and pathological neck nodes for all subsites.
In the clinical stage of N category (cN) for all cancers, except viral related cancers and mucosal melanoma, extra nodal cancer extension (ENE) has been added to the lymph node category (N).
N3a and N3b are now added. N3a being metastasis in a lymph node larger than 6 cm in greatest dimension and ENE negative and N3b being metastasis in any node (s) and clinically overt ENE positive.
| Regional Lymph Nodes (N) | |||
| N Category | Clinical N (cN) criteria | Pathological N (pN) Criteria | |
| Nx | Regional lymph nodes cannot be assessed | Regional lymph nodes cannot be assessed. | |
| N0 | No regional lymph node metastasis | No regional lymph node metastasis | |
| N1 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension with no extra nodal extension ENE(–) | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension with no extra nodal extension ENE(–) | |
| N2 | N2a | Metastasis in a single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–) | A single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–); or |
| Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(+) | |||
| N2b | Metastasis in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension, and ENE(–) | Metastasis in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(–) | |
| N2c | Metastasis in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, and ENE(–) | Metastasis in bilateral or contralateral lymph node(s), none larger than 6 cm in greatest dimension and ENE(–) | |
| N3 | N3a | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–) | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–) |
| N3b | Metastasis in any node(s) and clinically overt ENE(+) | 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 3 cm or smaller 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(+). |
|||
M Staging
Previous Mx (distant metastasis which cannot be assessed) category has been dropped in the eighth version of AJCC 8 TNM staging.
| Distant Metastasis (M) | |
| M Category | M Criteria |
| M0 | No distant metastasis |
| M1 | Distant metastasis |
Prognostic stage grouping
Based on the above, TNM prognostic stage groups are defined as follows.
| Prognostic Stage Groups | |||
| Stage | T | N | M |
| Stage 0 | Tis | N0 | M0 |
| Stage I | T1 | N0 | M0 |
| Stage II | T2 | N0 | M0 |
| Stage III | T3 | N0 | M0 |
| T1,2,3 | N1 | M0 | |
| Stage IVA | T4a | N0, 1 | M0 |
| T1,2,3,4a | N2 | M0 | |
| Stage IVB | T4b | Any N | M0 |
| Any T | N3 | M0 | |
| Any T | Any N | M1 | |
References
- Gospodarowicz MK, Brierley JD, Wittekind C, editors. TNM classification of malignant tumours. John Wiley & Sons; 2017 Jan 17.
- Lydiatt WM, Patel SG, O’Sullivan B, Brandwein MS, Ridge JA, Migliacci JC, Loomis AM, Shah JP. Head and neck cancers—major changes in the American Joint Committee on cancer eighth edition cancer staging manual. CA: a cancer journal for clinicians. 2017 Mar 1;67(2):122-37.