| Primary Tumor (T) | |
| Regional Lymph Nodes (N) | |
| Distant Metastasis (M) | |
This view displays the TNM formula. Please select appropriate value from the list for T/N/M variables. The result will be displayed, based on your selection of variables.
Definition of Primary Tumor (T)
| T Category | T Criteria |
|---|---|
| TX | Primary tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| Tis | Carcinoma in situ: intraepithelial tumor without invasion of the lamina propria, high-grade dysplasia |
| 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 penetrates the subserosal connective tissue without invasion of the visceral peritoneum or adjacent structures |
| T4 | Tumor invades the serosa (visceral peritoneum) or adjacent structures |
| T4a | Tumor invades the serosa (visceral peritoneum) |
| T4b | Tumor invades adjacent structures/organs |
A tumor may penetrate the muscularis propria with extension into the gastrocolic or gastrohepatic ligaments, or into the greater or lesser omentum, without perforation of the visceral peritoneum covering these structures. In this case, the tumor is classified as T3. If there is perforation of the visceral peritoneum covering the gastric ligaments or the omentum, the tumor should be classified as T4.
The adjacent structures of the stomach include the spleen, transverse colon, liver, diaphragm, pancreas, abdominal wall, adrenal gland , kidney, small intestine, and retroperitoneum.
Intramural extension to the duodenum or esophagus is not considered invasion of an adjacent structure, but is classified using the depth of the greatest invasion in any of these sites.
Definition of Regional Lymph Node (N)
| N Category | N Criteria |
|---|---|
| NX | Regional lymph node(s) 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 |
| N3a | Metastasis in seven to 15 regional lymph nodes |
| N3b | Metastasis in 16 or more regional lymph nodes |
Definition of Distant Metastasis (M)
| M Category | M Criteria |
|---|---|
| M0 | No distant metastasis |
| M1 | Distant metastasis |