2002 American Joint Committee on Cancer (AJCC) TNM Staging System for Nasopharynx Cancer

T1: Tumor confined to the nasopharynx
T2: Tumor extends to soft tissues
  T2a: Tumor extends to the oropharynx and/or nasal cavity without parapharyngeal extension*
  T2b: Any tumor 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, orbit, or masticator space

*Note: Parapharyngeal extension denotes posterolateral infiltration of tumor beyond the pharyngobasilar fascia.

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)* more than 6 cm and/or to supraclavicular fossa
  N3a: More than 6 cm in dimension
  N3b: Extension to the supraclavicular fossa**

Stage 0: Tis N0 M0
Stage I: T1 N0 M0
Stage IIa: T2a N0 M0
Stage IIb: T1 N1 M0, T2 N1 M0, T2a N1 M0, T2b N0 M0. T2b N1 M0
Stage III: T1 N2 M0, T2a N2 M0, T2b N2 M0, T3 N0 M0, T3 N1 M0, T3 N2 M0
Stage IVa: T4 N0 M0, T4 N1 M0, T4 N2 M0
Stage IVb: Any T N3 M0
Stage IVc: Any T Any N M1