Table 2.

Nodal staging of OPSCC based on the American Joint Commission on Cancer [20].

Stage	Nodal involvement
NX	The neck cannot or was not assessed.
N0	No nodal metastases; neck was evaluated.
N1	Single node, ipsilateral to primary tumor; ≤3 cm.
N2a	Single node, ipsilateral to primary tumor; 3–6 cm.
N2b	Multiple nodes, ipsilateral to primary tumor; ≤6 cm.
N2c	Single or multiple node; contralateral neck involved; all ≤6 cm.
N3	One or more nodes > 6 cm regardless of multiplicity or laterality.