What Are the Stages of Stomach Cancer?
Once a diagnosis of stomach cancer has been made, a number of tests may be performed to determine if and how far the cancer may have spread to the other layers of the stomach, nearby organs, and nearby lymph nodes. This process is called staging, and it is an important factor in deciding which treatment would be most beneficial to the patient.
CT scanning is often used for staging stomach cancer, as is PET scanning. A CT scan provides a roadmap and the PET scan looks at activity within the cancer cell. Both tests can be complementary to better define whether the cancer has spread or not.
Endoscopic ultrasound is another test that may be used during both diagnosis and staging.
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 (eg 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.
Statistics About Stomach Cancer
The American Cancer Society’s estimates for stomach cancer in the United States for 2013 are:
- About 21,600 diagnosed cases of stomach cancer (13,230 in men and 8,370 in women)
- About 10,990 deaths from this type of cancer (6,740 men and 4,250 women)
Stomach cancer mostly affects older people. The average age of people when they are diagnosed is 70. Almost two thirds of people with stomach cancer are 65 or older.
The average risk that a person will develop stomach cancer in their lifetime is about 1 in 116. This risk is slightly higher in men than in women, and can also be affected by a number of other factors.
Stomach cancer is much more common in other parts of the world, particularly in less developed countries, than in the United States. It is a leading cause of cancer-related deaths in the world.
Until the late 1930s, stomach cancer was the leading cause of cancer death in the United States. No longer. The reasons for this decline are not completely known, but may be linked to increased use of refrigeration for food storage. This made fresh fruits and vegetables more available and decreased the use of salted and smoked foods.
Some doctors think the decline may also be linked to the frequent use of antibiotics to treat infections. Antibiotics can kill the bacteria called Helicobacter pylori (H pylori), which is thought to be a major cause of stomach cancer.