The staging evaluation of Esophageal Cancer

After establishing a diagnosis of esophageal cancer, adequate staging is required, because staging is the most important step in choosing appropriate therapy. More than 50% of patients have unresectable or metastatic disease at the time of presentation. For the others, survival is closely related to the stage of the disease.
The staging evaluation allows patients to be assigned a clinical stage according to the American Joint Committee on Cancer tumor-node-metastasis (TNM) classification. Informed recommendations about therapy and appropriate information regarding prognosis depends on this clinical staging, an assessment that can, however, only approximate the true disease stage.

 Primary Tumor (T)

* TX: Primary tumor cannot be assessed
* T0: No evidence of primary tumor
* Tis: Carcinoma in situ
* T1: Tumor invades lamina propria (T1a) or submucosa (T1b)
* 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
* N1a: One to three nodes involved
* N1b: Four to seven nodes involved
* N1c: More than seven nodes involved

Distant Metastasis (M)

* MX: Distant metastasis cannot be assessed
* M0: No distant metastasis
* M1: Distant metastasis
1. Tumors of the lower thoracic esophagus:
- M1a: Metastases in celiac lymph nodes
- M1b: Other distant metastases
2. Tumors of the midthoracic esophagus:
- M1a: Not applicable
- M1b: Nonregional lymph nodes and/or other distant metastases
3. Tumors of the upper thoracic esophagus:
- M1a: Metastases in cervical nodes
- M1b: Other distant metastases