Stomach Cancer Stages

A cancer’s stage refers to how large the primary tumor is and how far the cancer has spread in the patient’s body. Knowing the stage helps the care team understand the disease and develop an appropriate treatment plan. It also impacts the patient’s prognosis, or chance for a successful treatment.

TNM stages

The TNM staging system is used for most cancers.

TNM staging describes cancer based on three main factors:

The size of the primary tumor (T) and whether it has invaded nearby tissues.
The cancer’s spread to nearby lymph nodes (N).
Whether the cancer has metastasized (M), or spread, to distant parts of the body.

Each TNM factor is assigned a number that reflects the extent of the cancer. Tumors (T) are scored between 1-4, nodes (N) 1-3, and metastasis (M) 0-1.

After all diagnostic and staging procedures are performed, your doctor should know the TNM stage of your cancer and be able to explain how this stage impacts your treatment and prognosis.

0 to IV stages

Often, TNM staging can be simplified into stages four stages (I-IV). For some cancers, there is also a stage 0. Larger numbers mean the cancer is more advanced and is generally more difficult to treat.

Stage 0 reflects the presence of abnormal cells that have not spread to tissue that is immediately nearby. Stage 0 is considered precancerous, though it could become cancer in the future. This stage is also called “in-situ,” which means “in its original place.” Not all cancers have a stage 0.
Stage I cancers are typically small and confined to the area where they began.
Stage II and Stage III cancers have spread to nearby tissue and/or lymph nodes.
Stage IV cancer has spread to distant areas of the body. This is also called metastatic cancer. Stage IV cancer often cannot be cured, but frequently can be managed like a chronic disease.

Stomach cancer 0-IV stages

Source: National Cancer Institute

Stage 0 stomach cancer

Stage 0 refers to carcinoma in situ. This means that abnormal cells are found in the mucosa. These abnormal cells may become cancer and spread into nearby normal tissue.  

Stage I stomach cancer

Stage I  is divided into stages IA and IB. 

In stage IA, 
- cancer has formed in the mucosa and may have spread to the submucosa.
In stage IB, 
- cancer has formed in the mucosa and may have spread to the submucosa and has spread to 1 or 2 nearby lymph nodes; or
- cancer has formed in the mucosa and has spread to the muscle layer.

Stage II stomach cancer

Stage II is divided into stages IIA and IIB. 

In stage IIA, 
- cancer may have spread to the submucosa and has spread to 3 to 6 nearby lymph nodes; or 
- cancer has spread to the muscle layer and to 1 or 2 nearby lymph nodes; or 
- cancer has spread to the subserosa.
In stage IIB, 
- cancer may have spread to the submucosa and has spread to 7 to 15 nearby lymph nodes; or 
- cancer has spread to the muscle layer and to 3 to 6 nearby lymph nodes; or 
- cancer has spread to the subserosa and to 1 or 2 nearby lymph nodes; or 
- cancer has spread to the serosa.

Stage III stomach cancer

Stage III is divided into stages IIIA, IIIB, and IIIC. 

In stage IIIA, 
- cancer has spread to the muscle layer and to 7 to 15 nearby lymph nodes; or
- cancer has spread to the subserosa and to 3 to 6 nearby lymph nodes; or
- cancer has spread to the serosa and to 1 to 6 nearby lymph nodes; or
- cancer has spread to nearby organs, such as the spleen, colon, liver, diaphragm, pancreas, abdomen wall, adrenal gland, kidney, or small intestine, or to the back of the abdomen.
In stage IIIB, 
- cancer may have spread to the submucosa or to the muscle layer and has spread to 16 or more nearby lymph nodes; or 
- cancer has spread to the subserosa or to the serosa and has spread to 7 to 15 nearby lymph nodes; or 
- cancer has spread to nearby organs, such as the spleen, colon, liver, diaphragm, pancreas, abdomen wall, adrenal gland, kidney, or small intestine, or to the back of the abdomen. Cancer has also spread to 1 to 6 nearby lymph nodes. 
In stage IIIC, 
- cancer has spread to the subserosa or to the serosa, and to 16 or more nearby lymph nodes; or
- cancer has spread to nearby organs, such as the spleen, colon, liver, diaphragm, pancreas, abdomen wall, adrenal gland, kidney, or small intestine, or to the back of the abdomen. Cancer also has spread to 7 or more nearby lymph nodes.