Oral cavity carcinoma (staging)
Oral cavity carcinoma staging refers to TNM staging of carcinomas involving the oral cavity. The vast majority of applicable cases are squamous cell carcinomas, but other epithelial and minor salivary gland cancers are also included. The following article reflects the 8 edition published by the American Joint Committee on Cancer (AJCC), published in 2017 and corrected in 2018 .
Primary tumor (T)
- TX: primary tumor cannot be assessed
- Tis: carcinoma in situ
- T1: tumor ≤2 cm in greatest dimension 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
- any tumor with DOI >10 mm, or
- tumor >4 cm with DOI ≤10 mm
- T4: moderately or very advanced
- T4a: moderately advanced local disease:
- tumor >4 cm with DOI >10 mm, or
- tumor invades adjacent structures (e.g. through cortical bone of mandible or maxilla, into the maxillary sinus, into the skin of face)*
- T4b: very advanced local disease:
- tumor invades masticator space, pterygoid plates, or skull base, and/or
- tumor encases the internal carotid artery
- T4a: moderately advanced local disease:
*Superficial erosion alone of bone/tooth socket by gingival primary is not sufficient to classify as T4
Regional lymph node (N)
Regional nodal status is defined the same as for most other cancers of the head and neck. See the main article, cervical lymph node (staging).
Distant metastases (M)
The terms pM0 and MX are not valid TNM categories. The following categories may be used:
- cM0: no evidence of metastases
- cM1: distant metastasis
- pM1: distant metastasis, microscopically confirmed
Stage groups
The prognostic stage groups are defined the same as for most other cancers of the head and neck:
- stage 0
- Tis, N0, M0
- stage I
- T1, N0, M0
- stage II
- T2, N0, M0
- stage III
- T3, N0, M0
- [T1, T2, T3], N1, M0
- stage IVA
- T4a, [N0, N1], M0
- [T1, T2, T3, T4a], N2, M0
- stage IVB
- [Any T], N3, M0
- T4b, [Any N], M0
- stage IVC
- [Any T], [Any N], M1
Changes since prior versions
The new classification places importance on depth of invasion for primary tumor staging , which is correlated with, but not the same as, tumor thickness assessed radiologically . Pathologically, the depth of invasion is defined relative to the horizon of the nearest normal mucosal surface . Thus, depth of invasion is greater than tumor thickness when the tumor is ulcerative, and depth of invasion is less than tumor thickness when the tumor is exophytic. Emerging research has demonstrated a high correlation between the radiologic depth of invasion measured on intraoperative ultrasound and the histopathologic depth of invasion .
The emphasis on depth of invasion supersedes and replaces the prior criterion of extrinsic tongue muscle infiltration for T4 disease, which was difficult to assess clinically and pathologically.
The dry vermilion lip has been removed from the definition of oral cavity; tumors affecting that site are instead classified with cutaneous carcinoma of the head and neck. Moreover, the distinction between lip and oral cavity for T4a criteria has been removed.
Nodal staging has changed, as with other head and neck sites, to emphasize extranodal extension.
See also
- oral cavity squamous cell carcinoma
- mucoepidermoid carcinoma
- WHO classification of head and neck tumors
- cervical lymph node levels
- cervical lymph node staging