A staging system is a way for your doctor to describe the extent of your cancer and then establish a treatment plan. The system most often used to stage stomach cancer in the United States is the American Joint Commission on Cancer (AJCC) TNM system. This divides cancer stages into 1 and 2 (early), 3 spread to surrounding lymph nodes and 4 to other organs (e.g. lung, liver and peritoneum)
TNM (tumor, node, metastasis) describes the stage of a cancer. This abbreviation summarizes the depth of penetration of the tumor into the stomach wall (T), whether it has spread to nearby lymph nodes (N), and whether it has metastasized, or spread, to other parts of the body (M).
- T describes the extent of the primary tumor (how far it has grown into the wall of the stomach and into nearby organs).
- N describes the spread to nearby (regional) lymph nodes.
- M indicates whether the cancer has metastasized (spread) to distant parts of the body. The most common sites of distant spread of stomach cancer are the liver, the peritoneum (the lining of the space around the digestive organs), and distant lymph nodes. Less common sites of spread include the lungs and brain.