TNM Definitions
AJCC Stage Groupings

Staging systems are all clinical staging and are based on the best possible estimate of the extent of disease before treatment.[1,2] Assessment of the primary tumor is based on inspection and palpation when possible and by both indirect mirror examination and direct endoscopy when necessary. The tumor must be confirmed histologically, and any other pathologic data obtained on biopsy may be included. Evaluation of the function of the cranial nerves is especially appropriate for tumors of the nasopharynx. The appropriate nodal drainage areas are examined by careful palpation.[3,4] Information from diagnostic imaging studies may be used in staging. Magnetic resonance imaging offers an advantage over computed tomographic scanning in the detection and localization of head and neck tumors and the distinction of lymph nodes from blood vessels.[5] Positron emission tomography scans may be useful in detecting skeletal metastases in patients with advanced nasopharyngeal cancer.[6]

If a patient has a relapse, a complete reassessment must be done to select the appropriate additional therapy.

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification to define nasopharyngeal cancer.[7]

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• 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.]

The distribution and the prognostic impact of regional lymph node spread from nasopharynx cancer, particularly of the undifferentiated type, are different from those of other head and neck mucosal cancers and justify the use of a different regional lymph node classification scheme.

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Unilateral metastasis in lymph node(s), not more than 6 cm in greatest dimension, above the supraclavicular fossa*
• N2: Bilateral metastasis in lymph node(s), not more than 6 cm in greatest dimension, above the supraclavicular fossa*
• N3: Metastasis in a lymph node(s)* larger than 6 cm and/or to supraclavicular fossa
  • N3a: larger than 6 cm
  • N3b: Extension to the supraclavicular fossa**

* [Note: Midline nodes are considered ipsilateral nodes.]

** [Note: Supraclavicular zone or fossa is relevant to the staging of nasopharyngeal carcinoma and is the triangular region originally described in the Ho-stage classification for nasopharyngeal cancer. It is defined by three points: (1) the superior margin of the sternal end of the clavicle; (2) the superior margin of the lateral end of the clavicle; and, (3) the point where the neck meets the shoulder. Note that this would include caudal portions of Levels IV and V. All cases with lymph nodes (whole or part) in the fossa are considered N3b.]

Distant metastasis (M)

• MX: Distant metastasis cannot be assessed
• M0: No distant metastasis
• M1: Distant metastasis

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

Results of radiation therapy for nasopharyngeal carcinoma (locoregional control and survival) are usually reported by T stage and N stage separately or by specific T and N subgroupings rather than by numerical stages I to IV. Outcome also depends on a variety of biologic and technical factors related to treatment.

References

1. Teo PM, Leung SF, Yu P, et al.: A comparison of Ho's, International Union Against Cancer, and American Joint Committee stage classifications for nasopharyngeal carcinoma. Cancer 67 (2): 434-9, 1991.  [PUBMED Abstract]
   
   
2. Lee AW, Foo W, Law SC, et al.: Staging of nasopharyngeal carcinoma: from Ho's to the new UICC system. Int J Cancer 84 (2): 179-87, 1999.  [PUBMED Abstract]
   
   
3. Mendenhall WM, Riggs CE Jr, Cassisi NJ: Treatment of head and neck cancers. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds.: Cancer: Principles and Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2005, pp 662-732. 
   
   
4. Laramore GE, ed.: Radiation Therapy of Head and Neck Cancer. Berlin: Springer-Verlag, 1989. 
   
   
5. Consensus conference. Magnetic resonance imaging. JAMA 259 (14): 2132-8, 1988.  [PUBMED Abstract]
   
   
6. Liu FY, Chang JT, Wang HM, et al.: [18F]fluorodeoxyglucose positron emission tomography is more sensitive than skeletal scintigraphy for detecting bone metastasis in endemic nasopharyngeal carcinoma at initial staging. J Clin Oncol 24 (4): 599-604, 2006.  [PUBMED Abstract]
   
   
7. Pharynx (including base of tongue, soft palate and uvula). In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 31-46.