Table 1

The tumor, node, metastasis (TNM) classification of the American Joint Committee on Cancer [24]

Primary Tumor (T)

TX
Primary tumor cannot be assessed
TO
No evidence of primary tumor
Tis
Carcinoma in situ

Nasopharynx
T1
Tumor confined to the nasopharynx
T2
Tumor extends to soft tissues of oropharynx and/or nasal fossa
     • T2a
     • without parapharyngeal extension
     • T2b
     • with parapharyngeal extension
T3
Tumor invades bony structures and/or paranasal sinuses
T4
Tumor with intracranial extension and/or involvement of cranial nerves, infratemporal fossa, hypopharynx, or orbit, or masticator space

Regional Lymph Nodes (N): Nasopharynx
The distribution of regional lymph node spread from nasopharyngeal cancer, particularly of the undifferentiated type, is different than that of other head and neck mucosal cancers and justifies use of a different N classification scheme. In children this does not have a prognostic impact.

NX
Regional lymph nodes cannot be assessed
N0
No regional lymph node metastasis
N1
Unilateral metastasis in lymph node(s), 6 cm or less in greatest dimension, above the supraclavicular fossa.
N2
Bilateral metastasis in lymph node (s) 6 cm or less in greatest dimension, above the supraclavicular fossa
N3
Metastasis in a lymph node(s)
     • N3a
     • greater than 6 cm in dimension
     • N3b
     • extension to the supraclavicular fossa

Distant Metastasis (M)
MX
Distant metastasis cannot be assessed
M0
No distant metastasis
M1
Distant metastasis

Brennan Orphanet Journal of Rare Diseases 2006 1:23   doi:10.1186/1750-1172-1-23