Stages of Stomach Cancer

Staging is the process of determining where cancer is located and how far it has spread, if at all. This determines the severity and extent of your cancer, helping doctors predict your prognosis and decide on the best treatment options. For example, early-stage stomach cancer may be treated with surgery alone, while more advanced cancer usually requires a combination of treatments, such as surgery and chemotherapy.

When doctors suspect you may have stomach cancer, they will order tests to confirm the diagnosis. These tests will give some information to estimate the stage of your cancer. This includes the size of the tumor, involvement of regional lymph nodes and if there is any distant spread.

While cancer is typically staged when first diagnosed and before any treatment, it can be staged again over the course of your treatment journey. Doctors first assign a clinical stage based on initial test results done before treatment. The clinical stage is generally used to plan the best treatment options and establish your prognosis.

If surgery is done to remove the gastric tumor, doctors can also determine the cancer’s pathological stage. This is derived from the results of earlier tests as well as those from the surgery. The pathological stage provides more detailed information about the cancer, making it a more accurate indicator of its progression in the body.

In some instances, the pathological stage can be different from the clinical stage. An example would be if the cancer is revealed during surgery to have spread to regional lymph nodes that may not be evident on imaging tests.

Some cancer patients may receive treatment before surgery to shrink the tumor and improve the chances of successful surgery. This is known as neoadjuvant therapy. Tests may be repeated after neoadjuvant therapy to assess the cancer’s response to treatment.

Doctors use classification systems to determine the stage of cancers. The most commonly used staging system for gastric cancer is the TNM system, developed by the American Joint Committee on Cancer (AJCC). TNM is an acronym for tumor (T), nodes (N) and metastasis (M), which are also the three broad categories of this system.

The TNM system uses different stage descriptions for different types of cancer. This means that each cancer type has its own version of the TNM categories. Therefore, different types of stomach cancer are staged differently.

Staging also differs for proximal stomach cancers that extend into the gastroesophageal junction. Doctors often stage and treat these as esophageal cancers.

The following covers the staging of adenocarcinomas, which account for almost 95% of all cancers of the stomach.

Tumor (T)

The T category describes the depth of invasion of the main (primary) tumor, including whether it has invaded nearby structures and organs. Stages in this category are assigned a letter or number (0 to 4). The higher the number after the T, the more it has grown into nearby tissues.

Nodes (N)

The N category describes any cancer spread to lymph nodes near the stomach. Lymph nodes are small, bean-shaped structures that form a network throughout the body. They drain away waste products and damaged cells and contain lymphocytes that fight infection and disease.

Cancers often spread from the primary tumor to surrounding lymph nodes before they reach other parts of the body. Stages in the N category are also assigned a number and letter. The higher the number after the N, the greater the spread of the cancer to nearby lymph nodes.

Metastasis (M)

The M category describes any cancer spread to distant parts of the body, such as the liver or lungs. This is known as metastasis.

A lowercase letter may be written in front of the T, N, and M categories to indicate whether the staging is clinical or pathological. A clinical stage is noted with “c” (e.g. cT1), while a pathological stage is noted with “p” (e.g. pT2).

Gastric cancers that are staged after neoadjuvant therapy are noted with a “y” in front of the category (e.g. ycT1).

Once the gastric cancer’s T, N and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. There are five stages for gastric cancer— stage 0, followed by stages I (1) through IV (4). Some stages have subdivisions as well, such as stages IIIA and IIIB.

The following categories are not listed in the table above:

• TX means the primary tumor cannot be assessed due to lack of information.
• T0 means there is no evidence of a primary tumor in the stomach.
• NX means nearby lymph nodes cannot be assessed due to a lack of information.
• MX means that distant metastasis cannot be evaluated due to a lack of information.

The higher the number of the stage, the more the cancer has spread. Early-stage gastric cancers usually have a better prognosis. Meanwhile, advanced stomach cancers generally have spread more extensively, have poorer prognosis and might require different kinds of treatment.

If you have been diagnosed with gastric cancer, understanding your cancer stage can help you better comprehend the severity of your condition, available treatments and their outcomes. It also helps you make more informed decisions and ask relevant questions to your cancer care team. This will help you stay on top of things as you navigate through this challenging journey. So, don’t hesitate to communicate any concerns or doubts you may have.