| Primary Tumor (T) | |
| Regional Lymph Nodes (N) | |
| Distant Metastasis (M) | |
| Histologic Grade (G) | |
| Tumor Location | |
This view displays the TNM formula. Please select appropriate value from the list for T/N/M/G variables. The result will be displayed, based on your selection of variables.
Definition of Primary Tumor (T)
| T Category | T Criteria |
|---|---|
| TX | Tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| Tis | High-grade dysplasia, defined as malignant cells confined to the epithelium by the basement membrane |
| T1 | Tumor invades the lamina propria, muscularis mucosae, or submucosa |
| T1a | Tumor invades the lamina propria or muscularis mucosae |
| T1b | Tumor invades the submucosa |
| T2 | Tumor invades the muscularis propria |
| T3 | Tumor invades adventitia |
| T4 | Tumor invades adjacent structures |
| T4a | Tumor invades the pleura, pericardium, azygos vein, diaphragm, or peritoneum |
| T4b | Tumor invades other adjacent structures, such as the aorta, vertebral body, or airway |
Definition of Regional Lymph Node (N)
| N Category | N Criteria |
|---|---|
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis in one or two regional lymph nodes |
| N2 | Metastasis in three to six regional lymph nodes |
| N3 | Metastasis in seven or more regional lymph nodes |
Definition of Distant Metastasis (M)
| M Category | M Criteria |
|---|---|
| M0 | No distant metastasis |
| M1 | Distant metastasis |
Histologic grade for squamous cell carcinoma is defined as follows:
| G | G Definition |
|---|---|
| G1 | Well-differentiated squamous cell carcinoma. In well-differentiated squamous cell carcinoma, there is prominent keratinization and a minor component of nonkeratinizing basal-like cells. The keratin component shows squamous pearls akin to the appearance of nonneoplastic squamous epithelium (normal esophageal squamous epithelium does not keratinize). Tumor cells are arranged in sheets, and mitotic counts are low compared with those for moderately and poorly differentiated tumors.49 |
| G2 | Moderately differentiated squamous cell carcinoma. This is the most common histologic type, demonstrating variable histologic features, ranging from parakeratotic to poorly keratinizing lesions. Generally, squamous pearl formation is absent. However, definite histologic criteria for moderately differentiated squamous cell carcinoma are not established, thus grading is affected by interobserver variability.49 |
| G3 | Poorly differentiated squamous cell carcinoma. This consists predominantly of basal-like cells forming large and small nests with frequent central necrosis. The nests consist of sheets or pavement-like arrangements of tumor cells, and occasionally are punctuated by small numbers of parakeratotic or keratinizing cells.49 Note that every effort should be made to avoid signing out a histologic grade as “undifferentiated.” If this cannot be resolved, the cancer should be staged as a G3 squamous cell carcinoma. |
| GX | Grade cannot be assessed |
| NA | Not Applicable |
Definition of Location Tumor(T)
Location plays a role in the stage grouping of esophageal squamous cancers. It is defined by the position of the epicenter of the tumor in the esophagus
| Location Category | Location Criteria |
|---|---|
| X | Location Unknown |
| Upper | Cervical esophagus to lower border of azygos vein |
| Middle | Lower border of azygos vein to lower border of inferior pulmonary vein |
| Lower | Lower border of inferior pulmonary vein to stomach, including gastroesophageal junction |