Stomach Cancer Stages
After someone is diagnosed with stomach cancer (gastric cancer), doctors will do exams and tests to help determine if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes the extent of the cancer in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer's stage when talking about survival statistics.
Although each person's cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.
The AJCC TNM staging system
The staging system most often used for stomach cancer is the American Joint Committee on Cancer (AJCC) TNM system, which was last updated in 2018.
This system is used to stage all stomach cancers (carcinomas) except those starting in the gastroesophageal junction (where the stomach and the esophagus meet) or those that start in the cardia (the first part of the stomach) and are growing into the gastroesophageal junction. Those cancers are staged (and often treated) like cancers of the esophagus. Other types of cancer that can start in the stomach, such as gastrointestinal stromal tumors (GISTs) and lymphomas, are staged differently as well.
The TNM system for stomach cancer is based on 3 key pieces of information:
The T category describes the extent of the main (primary) tumor, including how far it has grown into the layers of the stomach wall and if it has reached nearby structures or organs.
The 5 layers of the stomach wall include:
- Mucosa: the innermost layer, where nearly all stomach cancers start. The mucosa has 3 parts: epithelial cells, a layer of connective tissue (the lamina propria), and a thin layer of muscle (the muscularis mucosa).
- Submucosa: a supporting layer under the mucosa
- Muscularis propria: a thick layer of muscle that moves and mixes the stomach contents
- Subserosa
- Serosa: the outer, wrapping layer of the stomach
The N category describes any cancer spread to nearby lymph nodes.
The M category describes any spread (metastasis) to distant parts of the body, such as the liver or lungs.
Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced.
Stage grouping
Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. The earliest stage stomach cancers are called stage 0 (carcinoma in situ), and then range from stages I (1) through IV (4). The lower the number, the less the cancer has spread. See the table below for more details about the stage grouping for stomach cancer.
Staging can be done at different times
Stomach cancer might be staged at different times during the course of a person’s treatment.
Usually, the cancer is first given a clinical stage. This is based on the results of any physical exams, biopsies, imaging tests, and procedures (such as upper endoscopy or laparoscopy) that have been done. (These exams and tests are described in Tests for Stomach Cancer.) The clinical stage can be used to help plan treatment.
If surgery is done to remove the cancer, the pathological stage (also called the surgical stage) can be determined. This is based on the results of any exams or tests that have been done, as well as the results from the surgery. Sometimes the pathological stage is different from the clinical stage—for example, if surgery finds the cancer has spread farther than could be seen on imaging tests.
Some people might get other treatments before surgery, such as chemotherapy or radiation, to try to shrink the cancer and make the surgery easier. This is known as neoadjuvant treatment. Staging might be done again after this treatment to assess how well it worked.
The table below, describing the TNM stage grouping in more detail, is based on the pathological stage of the cancer. If your cancer has been clinically staged or if you have had neoadjuvant therapy, it's best to talk to your doctor about the specific stage for your situation.
AJCC Stage |
Stage grouping |
Stage description* |
0 |
Tis N0 M0 |
There is high grade dysplasia (very abnormal looking cells) in the stomach lining, OR there are cancer cells only in the top layer of cells of the mucosa (innermost layer of the stomach) that have not grown into deeper layers of tissue such as the lamina propria (Tis). The cancer has not spread to nearby lymph nodes (N0) or distant parts of the body (M0). This stage is also known as carcinoma in situ. |
IA |
T1 N0 M0 |
The main tumor has grown from the top layer of cells of the mucosa into the next layers below such as the lamina propria, the muscularis mucosa, or submucosa (T1). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IB
|
T1 N1 M0 |
The main tumor has grown from the top layer of cells of the mucosa into the next layers below such as the lamina propria, the muscularis mucosa, or submucosa (T1), AND the cancer has spread to 1 to 2 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2 N0 M0 |
The main tumor is growing into the muscularis propria layer (T2). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
|
IIA |
T1 N2 M0 |
The main tumor has grown from the top layer of cells of the mucosa into the next layers below such as the lamina propria, the muscularis mucosa, or submucosa (T1), AND the cancer has spread to 3 to 6 nearby lymph nodes (N2). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2 N1 M0 |
The main tumor is growing into the muscularis propria layer (T2), AND the cancer has spread to 1 to 2 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T3 N0 M0 |
The main tumor is growing into the subserosa layer (T3). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
|
IIB
|
T1 N3a M0 |
The main tumor has grown from the top layer of cells of the mucosa into the next layers below such as the lamina propria, the muscularis mucosa, or submucosa (T1), AND the cancer has spread to 7 to 15 nearby lymph nodes (N3a). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2 N2 M0 |
The main tumor is growing into the muscularis propria layer (T2), AND the cancer has spread to 3 to 6 nearby lymph nodes (N2). The cancer has not spread to distant parts of the body (M0). |
|
|
|
|
T3 N1 M0 |
The main tumor is growing into the subserosa layer (T3), AND the cancer has spread to 1 to 2 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4a N0 M0 |
The main tumor has grown through the stomach wall into the serosa, but it hasn’t grown into any of the nearby organs or structures (T4a). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
|
IIIA
|
T2 N3a M0 |
The main tumor is growing into the muscularis propria layer (T2), AND the cancer has spread to 7 to 15 nearby lymph nodes (N3a). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T3 N2 M0 |
The main tumor is growing into the subserosa layer (T3), AND the cancer has spread to 3 to 6 nearby lymph nodes (N2). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4a N1 M0 |
The main tumor has grown through the stomach wall into the serosa, but it has not grown into any of the nearby organs or structures (T4a). The cancer has spread to 1 to 2 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4a N2 M0 |
The main tumor has grown through the stomach wall into the serosa, but it has not grown into any of the nearby organs or structures (T4a). The cancer has spread to 3 to 6 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4b N0 M0 |
The main tumor has grown through the stomach wall and into nearby organs or structures (T4b). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
|
IIIB
|
T1 N3b M0 |
The main tumor has grown from the top layer of cells of the mucosa into the next layers below such as the lamina propria, the muscularis mucosa, or submucosa (T1), AND the cancer has spread to 16 or more nearby lymph nodes (N3b). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2 N3b M0 |
The main tumor is growing into the muscularis propria layer (T2), AND the cancer has spread to 16 or more nearby lymph nodes (N3b). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T3 N3a M0 |
The main tumor is growing into the subserosa layer (T3), AND the cancer has spread to 7 to 15 nearby lymph nodes (N3a). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4a N3a M0 |
The main tumor has grown through the stomach wall into the serosa, but it has not grown into any of the nearby organs or structures (T4a), AND the cancer has spread to 7 to 15 nearby lymph nodes (N3a). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4b N1 M0 |
The main tumor has grown through the stomach wall and into nearby organs or structures (T4b). The cancer has spread to 1 to 2 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4b N2 M0 |
The main tumor has grown through the stomach wall and into nearby organs or structures (T4b). The cancer has spread to 3 to 6 nearby lymph nodes (N1). The cancer has not spread to distant parts of the body (M0). |
|
IIIC |
T3 N3b M0 |
The main tumor is growing into the subserosa layer (T3), AND the cancer has spread to 16 or more nearby lymph nodes (N3b). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T4a N3b M0 |
The main tumor has grown through the stomach wall into the serosa, but it has not grown into any of the nearby organs or structures (T4a), AND the cancer has spread to 16 or more nearby lymph nodes (N3b). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4b N3a M0 |
The main tumor has grown through the stomach wall and into nearby organs or structures (T4b), AND the cancer has spread to 7 to 15 nearby lymph nodes (N3a). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4b N3b M0 |
The main tumor has grown through the stomach wall and into nearby organs or structures (T4b), AND the cancer has spread to 16 or more nearby lymph nodes (N3b). The cancer has not spread to distant parts of the body (M0). |
|
IV |
Any T Any N M1 |
The cancer might or might not have grown into any of the layers of the stomach wall (Any T), and it might or might not have spread to nearby lymph nodes (Any N). The cancer has spread to distant organs such as the liver, lungs, brain, or the peritoneum (the lining of the space around the digestive organs) (M1). |
*The following additional categories are not listed in the table above:
- TX: Main tumor cannot be assessed due to lack of information.
- T0: No evidence of a primary tumor.
- NX: Regional lymph nodes cannot be assessed due to lack of information.
Stomach cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.
For more general information on how cancer is staged, see Cancer Staging.
- Written by
- References
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
American Joint Committee on Cancer. Stomach Cancer. In: AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer; 2017: 203–220.
Last Revised: January 22, 2021
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
American Cancer Society Emails
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.
