TNM Definitions
AJCC Stage Groupings

The staging systems are all clinical staging and are based on the best possible estimate of the extent of disease before treatment. The assessment of the primary tumor is based on inspection and palpation, when possible, and by both indirect mirror examination and direct endoscopy. The tumor must be confirmed histologically, and any other pathologic data obtained from a biopsy may be included. Additional radiographic studies may be included. As an adjunct to clinical examination, computed tomography and/or magnetic resonance imaging are needed for an accurate staging of laryngeal and hypopharyngeal carcinomas because both cross-sectional imaging modalities are known to reliably evaluate deep tumor infiltration.[1-3] The appropriate nodal drainage areas are examined by careful palpation. If a patient relapses, complete restaging must be done to select the appropriate additional therapy.

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification.[4]

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• T1: Tumor limited to one subsite* of the hypopharynx and 2 cm or less in greatest dimension
• T2: Tumor invades more than one subsite* of the hypopharynx or an adjacent site, or measures more than 2 cm but 4 cm or less in greatest diameter without fixation of hemilarynx
• T3: Tumor measures more than 4 cm in greatest dimension or with fixation of hemilarynx
• T4a: Tumor invades thyroid/cricoid cartilage, hyoid bone, thyroid gland, esophagus, or central compartment soft tissue, which includes prelaryngeal strap muscles and subcutaneous fat
• T4b: Tumor invades prevertebral fascia, encases carotid artery, or involves mediastinal structures

  *Subsites of the hypopharynx are as follows:

  • Pharyngoesophageal junction (i.e., the postcricoid area), extending from the level of the arytenoid cartilages and connecting folds to the inferior border of the cricoid cartilage.
  • Pyriform sinus, extending from the pharyngoepiglottic fold to the upper end of the esophagus, bounded laterally by the thyroid cartilage and medially by the surface of the aryepiglottic fold and the arytenoid and cricoid cartilages.
  • Posterior pharyngeal wall, extending from the level of the floor of the vallecula to the level of the cricoarytenoid joints.

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Metastasis in a single ipsilateral lymph node, no larger than 3 cm in greatest dimension
• N2: Metastasis in a single ipsilateral lymph node, larger than 3 cm but no larger than 6 cm in greatest dimension, or in multiple ipsilateral lymph nodes, no larger than 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, no larger than 6 cm in greatest dimension
  • N2a: Metastasis in a single ipsilateral lymph node larger than 3 cm but no larger than 6 cm in greatest dimension
  • N2b: Metastasis in multiple ipsilateral lymph nodes, no larger than 6 cm in greatest dimension
  • N2c: Metastasis in bilateral or contralateral lymph nodes, no larger than 6 cm in greatest dimension
• N3: Metastasis in a lymph node larger than 6 cm in greatest dimension

In clinical evaluation, the actual size of the nodal mass should be measured, and allowance should be made for intervening soft tissues. Most masses larger than 3 cm in diameter are not single nodes but confluent nodes or tumors in soft tissues of the neck. There are three stages of clinically positive nodes: N1, N2, and N3. The use of subgroups a, b, and c is not required but recommended. Midline nodes are considered homolateral nodes.

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 II

• T2, N0, M0

Stage III

• T3, N0, M0
• T1, N1, M0
• T2, N1, M0
• T3, N1, M0

Stage IVA

• T4a, N0, M0
• T4a, N1, M0
• T1, N2, M0
• T2, N2, M0
• T3, N2, M0
• T4a, N2, M0

Stage IVB

• T4b, any N, M0
• Any T, N3, M0

Stage IVC

• Any T, any N, M1

References

1. Thabet HM, Sessions DG, Gado MH, et al.: Comparison of clinical evaluation and computed tomographic diagnostic accuracy for tumors of the larynx and hypopharynx. Laryngoscope 106 (5 Pt 1): 589-94, 1996.  [PUBMED Abstract]
   
   
2. Becker M: Larynx and hypopharynx. Radiol Clin North Am 36 (5): 891-920, vi, 1998.  [PUBMED Abstract]
   
   
3. Keberle M, Kenn W, Hahn D: Current concepts in imaging of laryngeal and hypopharyngeal cancer. Eur Radiol 12 (7): 1672-83, 2002.  [PUBMED Abstract]
   
   
4. 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. 
   
   

Back to Top

< Previous Section  |  Next Section >