Table 2.
Clinical assessment of regional lymph nodes (cN).
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis in a single ipsilateral lymph node, ≤ 3 cm in greatest dimension and ENE(−) |
| N2 | Metastasis in single ipsilateral lymph node, > 3 cm but not > 6 cm in greatest dimension and ENE(−); or metastases in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension and ENE(−); or in bilateral or contralateral lymph node(s), none > 6 cm in greatest dimension and ENE(−) |
| N2a | Metastasis in a single ipsilateral node > 3 cm but not > 6 cm in greatest dimension and ENE(−) |
| N2b | Metastases in multiple ipsilateral nodes, none > 6 cm in greatest dimension and ENE(−) |
| N2c | Metastases in bilateral or contralateral lymph node(s), none > 6 cm in greatest dimension and ENE(−) |
| N3 | Metastasis in a lymph node > 6 cm in greatest dimension and ENE(−); or Metastasis in any node(s) with clinically overt ENE(+) (ENEc) |
| N3a | Metastasis in a lymph node > 6 cm in greatest dimension and ENE(−) |
| N3b | Metastasis in any node(s) with clinically overt ENE(+) (ENEc) |
Note: Midline nodes are considered ipsilateral nodes. ENEc is defined as invasion of skin, infiltration of musculature, dense tethering or fixation to adjacent structures, or cranial nerve, brachial plexus, sympathetic trunk, or phrenic nerve invasion with dysfunction.
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(+).
From: AJCC Cancer Staging Form Supplement. Last updated 05 June, 2018. Amin MB, E.S., Greene FL, et al, eds, AJCC Cancer Staging Manual. 8th ed. Springer International Publishing: American Joint Commission on Cancer; 2017, New York.