TNM Definitions
AJCC Stage Groupings

The stage determines whether the intent of the therapeutic approach will be curative or palliative. The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification.[1]

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• T1: Tumor invades lamina propria or submucosa
• T2: Tumor invades muscularis propria
• T3: Tumor invades adventitia
• T4: Tumor invades adjacent structures

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Regional lymph node metastasis

Distant metastasis (M)

• MX: Distant metastasis cannot be assessed
• M0: No distant metastasis
• M1: Distant metastasis
  • Tumors of the lower thoracic esophagus:
    • M1a: Metastasis in celiac lymph nodes
    • M1b: Other distant metastasis
  • Tumors of the midthoracic esophagus:
    • M1a: Not applicable
    • M1b: Nonregional lymph nodes and/or other distant metastasis
  • Tumors of the upper thoracic esophagus:
    • M1a: Metastasis in cervical nodes
    • M1b: Other distant metastasis

For tumors of the midthoracic esophagus, use only M1b because these tumors with metastases in nonregional lymph nodes have equally poor prognoses as do those with metastases in other distant sites.

Stage 0

• Tis, N0, M0

Stage I

• T1, N0, M0

Stage IIA

• T2, N0, M0
• T3, N0, M0

Stage IIB

• T1, N1, M0
• T2, N1, M0

Stage III

• T3, N1, M0
• T4, any N, M0

Stage IV

• Any T, any N, M1

Stage IVA

• Any T, any N, M1a

Stage IVB

• Any T, any N, M1b

The current staging system for esophageal cancer is based largely on retrospective data from the Japanese Committee for Registration of Esophageal Carcinoma. It is most applicable to patients with squamous cell carcinomas of the upper third and middle third of the esophagus, as opposed to the increasingly common distal esophageal and gastroesophageal junction adenocarcinomas.[2] In particular, the classification of involved abdominal lymph nodes as M1 disease has been criticized. The presence of positive abdominal lymph nodes does not appear to carry as grave a prognosis as metastases to distant organs.[3] Patients with regional and/or celiac axis lymphadenopathy should not necessarily be considered to have unresectable disease caused by metastases. Complete resection of the primary tumor and appropriate lymphadenectomy should be attempted when possible.

References

1. Esophagus. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 91-8. 
   
   
2. Iizuka T, Isono K, Kakegawa T, et al.: Parameters linked to ten-year survival in Japan of resected esophageal carcinoma. Japanese Committee for Registration of Esophageal Carcinoma Cases. Chest 96 (5): 1005-11, 1989.  [PUBMED Abstract]
   
   
3. Korst RJ, Rusch VW, Venkatraman E, et al.: Proposed revision of the staging classification for esophageal cancer. J Thorac Cardiovasc Surg 115 (3): 660-69; discussion 669-70, 1998.  [PUBMED Abstract]