According to the TNM staging system, stomach cancer ranges from stages 0 to 4. At every stage, the stomach contains some abnormal cells.
In later stages, those cells grow and spread to nearby lymph nodes. The final stage is when the cancer has spread to distant organs.
Staging aims to see how much the stomach cancer has grown and how far it might have spread.
This information allows doctors to decide whether it is possible to cure the cancer and which treatment is most appropriate.
This article explains how staging works for stomach cancer. It provides a breakdown of the TNM staging system and describes stomach cancer stages.
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The American Joint Committee on Cancer (AJCC) has created a method for staging certain cancers called the TNM system.
The TNM system uses the
- Tumors (T): The size, amount, and location of any tumors.
- Nodes (N): The number of nearby lymph nodes where the cancer has spread to.
- Metastasis (M): The presence of cancer spread to distant organs.
If the cancer has not spread to nearby lymph nodes or distant organs, professionals use the labels ‘N0’ and ‘M0.’
Stages 1–3 have sub-stages with letters ‘A’ to ‘C.’ The sub-stages have multiple groupings. This means that different combinations of T, N, and M properties can count as the same sub-stage.
Although the TNM staging shows how large the tumor is and where it has spread, many doctors use the following terms to describe cancer:
- Localized: The tumor is localized to the initial area (T1), and the cancer has not spread to any lymph nodes or organs. Surgery is an appropriate treatment.
- Locally advanced: All other T or N stages but without distant metastasis. Chemotherapy, radiation, and surgery are some appropriate treatment options.
- Metastatic: The disease has spread to distant organs. At this point, doctors usually treat the cancer with palliative chemo.
The tables below list and describe the stages.
Stage 0 has no sub-stages:
| Stage grouping | Stage description |
| Tis N0 M0 | The stomach lining contains abnormal-looking cells. Or, cancer cells exist in the top layer of the stomach’s innermost layer (mucosa) but have not grown into deeper tissue layers. |
Stage 1 has sub-stages 1A and 1B. There is only one stage 1A grouping:
| Stage 1A grouping | Stage description |
| T1 N0 M0 | The main tumor has spread from the mucosa into deeper stomach layers, such as the lamina propria, the muscularis mucosa, or the submucosa. |
There are two stage 1B groupings:
| Stage 1B groupings | Stage description |
| T1 N1 M0 | The primary tumor has spread from the mucosa into deeper stomach layers. The cancer has also spread to up to 2 nearby lymph nodes. |
| T2 N0 M0 | The main tumor has grown into the muscularis propria layer. |
Stage 2 has sub-stages 2A and 2B. There are three stage 2A groupings:
| Stage 2A groupings | Stage description |
| T1 N2 M0 | The main tumor has spread from the mucosa into deeper stomach layers. The cancer has also spread to 3–6 nearby lymph nodes. |
| T2 N1 M0 | The main tumor has grown into the muscularis propria layer. The cancer has also spread to up to 2 nearby lymph nodes. |
| T3 N0 M0 | The main tumor has grown into the subserosa layer. |
There are four stage 2B groupings:
| Stage 2B groupings | Stage description |
| T1 N3a M0 | The main tumor has grown from the mucosa, into deeper stomach layers. The cancer has also spread to 7–15 nearby lymph nodes. |
| T2 N2 M0 | The main tumor has grown into the muscularis propria layer. The cancer has also spread to between 3–6 nearby lymph nodes. |
| T3 N1 M0 | The main tumor has grown into the subserosa layer. The cancer has also spread to up to 2 nearby lymph nodes. |
| T4a N0 M0 | The main tumor has grown into the serosa, though not into any nearby organs or structures. |
Stage 3 has sub-stages 3A, 3B, and 3C. There are five stage 3A groupings:
| Stage 3A groupings | Stage description |
| T2 N3a M0 | The main tumor has grown into the muscularis propria layer. The cancer has also spread to 7–15 nearby lymph nodes. |
| T3 N2 M0 | The main tumor has grown into the subserosa layer. The cancer has also spread to 3–6 nearby lymph nodes. |
| T4a N1 M0 | The main tumor has grown into the serosa, though not into any nearby organs or structures. The cancer has also spread to up to 2 nearby lymph nodes. |
| T4a N2 M0 | The main tumor has grown into the serosa, though not into any nearby organs or structures. The cancer has also spread to 3–6 nearby lymph nodes. |
| T4b N0 M0 | The main tumor has grown into nearby organs or structures. |
There are six stage 3B groupings:
| Stage 3B groupings | Stage description |
| T1 N3b M0 | The main tumor has grown from the mucosa into deeper stomach layers. The cancer has also spread to 16 or more nearby lymph nodes. |
| T2 N3b M0 | The main tumor has grown into the muscularis propria layer. The cancer has also spread to 16 or more nearby lymph nodes. |
| T3 N3a M0 | The main tumor has grown into the subserosa layer. The cancer has also spread to 7–15 nearby lymph nodes. |
| T4a N3a M0 | The main tumor has grown into the serosa, though not into any nearby organs or structures. The cancer has also spread to 7–15 nearby lymph nodes. |
| T4b N1 M0 | The main tumor has grown into nearby organs or structures. The cancer has also spread to up to 2 nearby lymph nodes. |
| T4b N2 M0 | The main tumor has grown into nearby organs or structures. The cancer has also spread to 3–6 nearby lymph nodes. |
There are four stage 3C groupings:
| Stage 3C groupings | Stage description |
| T3 N3b M0 | The main tumor has grown into the subserosa layer. The cancer has also spread to 16 or more nearby lymph nodes. |
| T4a N3b M0 | The main tumor has grown into the serosa, though not into any nearby organs or structures. The cancer has also spread to 16 or more nearby lymph nodes. |
| T4b N3a M0 | The main tumor has grown into nearby organs or structures. The cancer has also spread to 7–15 nearby lymph nodes. |
| T4b N3b M0 | The main tumor has grown into nearby organs or structures. The cancer has also spread to 16 or more nearby lymph nodes. |
Stage 4 has no sub-stages:
| Stage 4 grouping | Stage description |
| Any T Any N M1 | The cancer may have grown into any layer of the stomach wall. It may also have spread to nearby lymph nodes. The cancer has spread to distant organs. |
Stomach cancer develops in stages. By staging stomach cancers, doctors can recommend the most effective treatments to their patients.
The TNM system is a useful way for doctors to stage stomach cancers. According to this system, stomach cancer develops in stages 0 to 4. Many of these stages have sub-stages, which can take numerous forms.