Stomach Cancer Stages / Staging

The TNM Staging System

The American Joint Committee on Cancer (AJCC) developed the TNM staging system for evaluating the extent and spread of stomach cancer. The staging process is a basis for selecting treatment options and helping doctors communicate potential outcomes (prognosis). The TNM system considers three important factors:

• T - Describes the size and growth of the primary stomach tumor.
• N - Provides information about stomach cancer found in regional lymph nodes.
• M - Indicates whether the cancer has metastasized, or spread to other areas.

Each of these categories are rated on a numbered scale, the higher the number indicates increased severity. These categories are then grouped into stomach cancer stages from 0-IV.

Stomach Cancer Stages

Based on information collected using the TNM system, doctors will categorize the cancer into one of the following stages:

Stage 0 Stomach Cancer

Stage 0 stomach cancer is an early stage of stomach cancer that may also be referred to as carcinoma in situ because the cancer has not spread into any nearby tissue. In this stage, the cancer has not yet spread to the inner layer of cells that line the stomach.

Stage I Stomach Cancer

Stage IA stomach cancer occurs when the following conditions are met:

• The cancer has grown beneath the top layer of cells in the mucosa but has not grown into the main muscle layer of the stomach. The cancer has not spread to any lymph nodes or anywhere else.

Stage IB stomach cancer occurs when one of the following conditions are met.

• The conditions of stage IA are met, and the cancer has also spread to one or two lymph nodes near the stomach, but not to any other tissues or organs.
• The cancer has grown into the main muscle layer of the stomach wall, but has not spread to nearby lymph nodes, tissues or organs.

Stage II Stomach Cancer

Stage IIA stomach cancer occurs when one of the following conditions are met:

• The cancer has grown beneath the top layer of cells. It has not reached the main muscle layer, but it has spread to between three and six lymph nodes near the stomach. Distant sites have not been affected.
• The cancer has grown into the main muscle layer of the stomach. It has spread to one or two nearby lymph nodes, but has not spread to distant sites.
• The cancer has grown through the main muscle layer into the subserosa, but has not grown through all the layers to the outside of the stomach. It has not spread to any nearby lymph nodes, tissues, or organs outside of the stomach.

Stage IIB occurs when one of the following conditions are met:

• The cancer has grown beneath the top layer of cells but not into the main muscle layer. It has spread to seven or more lymph nodes near the stomach. Tissues and organs outside the stomach remain unaffected.
• The cancer has grown into the main muscle layer. It has spread to between three and six lymph nodes near the stomach, but it has not spread to any tissues or organs outside the stomach.
• The cancer has grown into the subserosa layer, but not completely through all the layers to the outside of the stomach. It has spread to one or two nearby lymph nodes, but has not spread to tissues or organs outside the stomach.
• The cancer has grown completely through all the layers of stomach wall into the outer covering of the stomach, but has not started growing into other nearby organs or tissues. It has not spread to any nearby lymph nodes or distant sites.

Stage III Stomach Cancer

Stage IIIA occurs when one of the following conditions are met:

• The cancer has grown into the main muscle layer of the stomach. It has spread to seven or more lymph nodes but has not spread to tissues or organs outside the stomach.
• The cancer has grown into the subserosa layer, but not completely through all the layers to the outside of the stomach. It has spread to between three and six nearby lymph nodes, but has not spread to tissues or organs outside the stomach.
• The cancer has grown completely through all the layers of the stomach wall into the outer covering of the stomach, but has not started growing into nearby organs or tissues. It has spread to one or two nearby lymph nodes, but has not spread to distant sites.

Stage IIIB occurs when one of the following conditions are met:

• The cancer has grown into the subserosa layer, but not completely through all the layers to the outside of the stomach. It has spread to seven or more nearby lymph nodes, but has not spread to distant sites.
• The cancer has grown completely through all the layers of the stomach wall into the serosa, but has not started growing into nearby organs or tissues. It has spread to three to six nearby lymph nodes, but has not spread to distant sites.
• The cancer has grown through the stomach wall and into nearby organs or structures. It may also have spread to up to two nearby lymph nodes. It has not spread to distant sites.

Stage IIIC occurs when one of the following conditions are met.

• The cancer has grown completely through all the layers of the stomach wall into the serosa, but has not started growing into nearby organs or tissues. It has spread to seven or more nearby lymph nodes (N3), but has not spread to distant sites.
• The cancer has grown through the stomach wall and into nearby organs or structures. It has spread to three or more nearby lymph nodes. It has not spread to distant sites.

Stage IV Stomach Cancer

Stage IV stomach cancer occurs when the cancer has spread to distant organs such as the liver, lungs, brain or bones.

Understanding Stomach Cancer Staging

In addition to considering the TNM stages of stomach cancer, many doctors also take into account whether or not the cancer can be completely removed by a surgical procedure (resectable). Surgery, however, may not always be a viable treatment option for stomach cancer. In cases where the disease has spread to distant organs, doctors may use another approach in treating the cancer.

The stomach cancer staging process is the time when you and your doctors can work together to determine the best course of treatment, depending on your personal preferences and needs. To learn more about CTCA and how stomach cancer staging is used to help determine patients’ treatment plans, call 1-800-615-3055 or chat online with one of our Oncology Information Specialists.

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