Cancer staging is a term used to refer to describing the tumor's size and whether or not it has spread beyond the area where it began.

Staging systems are constantly being updated to be able to help doctors plan the best treatment and help give them an idea of the probably outcome of treatment.

Your doctors will describe your cancer using the TNM and number staging systems.

TNM staging

This is the most commonly used staging system for stomach cancer.

T refers to the size of the tumor and the degree to which it has spread; it is numbered 0 to 4.

N indicates whether the nearby lymph nodes contain cancer cells, numbered 0 to 3 depending on how many nodes are affected.

M indicates whether the cancer has spread to other parts of the body (metastatic). M0 if it hasn't spread, M1 if it has.

For example, a given cancer can be described as T3 N2 M0.

Numeric staging

With this the stage of the stomach cancer is assigned a number from 1 to 4.

Stage 1

The cancer is located only in the lining of the stomach (mucosa) and may have spread to 1-2 lymph nodes.

or

The cancer has grown into the muscle layer of the stomach but has not spread to the lymph nodes.

Stage 2

The cancer is located only in the lining of the stomach (mucosa) and has spread to 3 or more lymph nodes.

or

The cancer has grown into the muscle layer and has spread to 1-6 lymph nodes. or

The cancer has reached the outer layer of the stomach, but only affects 1-2 lymph nodes.

or

The cancer has spread through the stomach wall but has not affected other nearby tissues or lymph nodes.

Doctors sometimes call stomach cancers in stages 1 and 2 "early-stage stomach cancer."

Stage 3

The cancer has grown into the muscle layer and has spread to 7 or more lymph nodes. or

The cancer has reached the outer layer of the stomach and affects 3 or more lymph nodes.

or

The cancer has spread through the wall of the stomach, extending into the lymph nodes and/or nearby tissues such as the liver, esophagus, or abdominal wall.

Doctors refer to stage-3 stomach cancer as "locally advanced cancer."

Stage 4

The cancer has spread beyond the stomach to other parts of the body, such as the lungs or bones.

Doctors usually call stage-four cancer "metastatic."

GRADING

Grading has to do with how the cancer cells look under the microscope compared to normal cells. Knowing the grade of cancer helps your doctor decide if you need additional treatment after surgery.

Grade 1

Low-grade, or well-differentiated cancer: this means the cancer cells resemble normal cells and in general grow slowly and are less likely to spread.

Grade 2

Moderate or intermediate cancer: this means that the cancer cells have a more abnormal appearance and are slightly faster-growing.

Grade 3

High-grade or poorly differentiated cancer: this means that the cancer cells look very different than normal cells and can grow more quickly.