Oropharyngeal (p16-negative) cancer (staging)

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Oropharyngeal (p16-) cancer staging refers to TNM staging of carcinomas originating in the oropharynx that are not human papillomavirus (HPV)-associated. This system most commonly pertains to squamous cell carcinomas that tested negative for p16, an immunohistochemical proxy for HPV infection, or were not tested. Also included are minor salivary cancers and neuroendocrine carcinomas, in which p16 assessment is not required or contributory. The following article reflects the 8 edition published by the American Joint Committee on Cancer, published in 2017 .

Primary tumor (T)

TX: primary tumor cannot be assessed
Tis: carcinoma in situ
T1: tumor ≤2 cm in greatest dimension
T2: tumor >2 cm and ≤4 cm
T3
- tumor >4 cm, or
- tumor extension to lingual surface of epiglottis
T4: moderately or very advanced
- T4a: moderately advanced local disease in which tumor invades any of the following:
  - larynx (except lingual surface of epiglottis)
  - extrinsic muscles of the tongue (except palatoglossus within the oropharynx)
  - medial pterygoid muscle
  - hard palate
  - mandible
- T4b: very advanced local disease in which tumor encases carotid artery or invades any of the following:
  - lateral pterygoid muscle
  - pterygoid plates
  - lateral nasopharynx
  - skull base

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 8th edition staging system separated HPV-associated and non-HPV-associated oropharyngeal cancers . Otherwise, the T category definitions did not change from the 7th edition staging system. Nodal staging was changed, as with other head and neck sites, to emphasize extranodal extension.