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. 2016 Feb 16;34(16):1848–1854. doi: 10.1200/JCO.2015.64.6448

Table A1.

AJCC (ed 7) Regional Lymph Node (N) Classification for Nasopharynx and Oropharynx/Hypopharynx Cancer

Classification Description by Cancer Type
Nasopharynx Cancer Oropharynx/Hypopharynx Cancer*
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 Unilateral metastasis in cervical lymph node(s), ≤ 6 cm in greatest dimension, above the supraclavicular fossa, and/or unilateral or bilateral, retropharyngeal lymph nodes, ≤ 6 cm in greatest dimension Metastasis in a single ipsilateral lymph node, ≤ 3 cm in greatest dimension
N2 Bilateral metastasis in cervical lymph node(s), ≤ 6 cm in greatest dimension, above the supraclavicular fossa Metastasis in a single ipsilateral lymph node, > 3 cm but not > 6 cm in greatest dimension, or in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, none > 6 cm in greatest dimension
N2a Not specified Metastasis in a single ipsilateral lymph node > 3 cm but not > 6 cm in greatest dimension
N2b Not specified Metastasis in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension
N2c Not specified Metastasis in bilateral or contralateral lymph nodes, none > 6 cm in greatest dimension
N3 Metastasis in a lymph node(s) > 6 cm and/or to supraclavicular fossa Metastasis in a lymph node > 6 cm in greatest dimension
N3a > 6 cm in dimension Not specified
N3b Extension to the supraclavicular fossa‡ Not specified

NOTE. Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, IL. The original source for this information is the AJCC Cancer Staging Manual (ed 7), published in 2010 by Springer.18

*

Metastases at level VII are considered regional lymph node metastases, originally described by Ho (Ho JHC: IARC Scientific Publication 20, 1978, pp 99–113). It is defined by three points: the superior margin of the sternal end of the clavicle, the superior margin of the lateral end of the clavicle, and the point where the neck meets the shoulder. Note that this definition would include caudal portions of levels IV and VB. All cases with lymph nodes (whole or part) in the fossa were considered N3b.

Midline nodes are considered ipsilateral nodes.

Supraclavicular zone or fossa is relevant to the staging of nasopharyngeal carcinoma and is the triangular region.