Stomach cancer

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Stages of stomach cancer

Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the organ have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).

The most common staging system for stomach cancer is the TNM system. For stomach cancer there are 5 stages – stage 0 followed by stages 1 to 4. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.

When describing the stage, doctors may use the words local, regional or distant. Local means that the cancer is only in the stomach and has not spread to other parts of the body. Regional means close to the stomach or around it. Distant means in a part of the body farther from the stomach.

Find out more about staging cancer.

The stomach is made up of different layers of tissues. The stage often depends on which layer the tumour has grown into.

The Stomach

Stage 0 (carcinoma in situ)

The tumour is only within the epithelium of the inner lining (mucosa) of the stomach. Doctors may describe it as high-grade dysplasia, which is a precancerous condition.

Stage 1A

The tumour has grown into the layer of connective tissue in the mucosa, the layer of muscle in the mucosa, or the layer of connective tissue that surrounds the mucosa (submucosa).

Stage 1B

One of the following applies:

  • The tumour has grown into the layer of connective tissue or muscle in the mucosa or into the submucosa. The cancer has also spread to 1 or 2 lymph nodes near the stomach.
  • The tumour has grown into the thick muscle layer of the stomach (muscularis propria).

Stage 2A

One of the following applies:

  • The tumour has grown into the layer of connective tissue or muscle in the mucosa or into the submucosa. The cancer has also spread to 3 to 6 lymph nodes near the stomach.
  • The tumour has grown into the muscularis propria. The cancer has also spread to 1 or 2 lymph nodes near the stomach.
  • The tumour has grown into the area between the muscularis propria and the outer covering of the stomach (serosa). This area is called the subserosa.

Stage 2B

One of the following applies:

  • The tumour has grown into the layer of connective tissue or muscle in the mucosa or into the submucosa. The cancer has also spread to 7 to 15 lymph nodes near the stomach.
  • The tumour has grown into the muscularis propria. The cancer has also spread to 3 to 6 lymph nodes near the stomach.
  • The tumour has grown into the subserosa. The cancer has also spread to 1 or 2 lymph nodes near the stomach.
  • The tumour goes through the serosa.

Stage 3A

One of the following applies:

  • The tumour has grown into the muscularis propria. The cancer has also spread to 7 to 15 lymph nodes near the stomach.
  • The tumour has grown into the subserosa. The cancer has also spread to 3 to 6 lymph nodes near the stomach.
  • The tumour goes through the serosa. The cancer has also spread to 1 to 6 lymph nodes near the stomach.
  • The tumour has grown into nearby organs or areas, such as the spleen, colon, small intestine, liver, diaphragm or abdominal wall.

Stage 3B

One of the following applies:

  • The tumour has grown into the layer of connective tissue or muscle in the mucosa, the submucosa or the muscularis propria. The cancer has also spread to 16 or more lymph nodes near the stomach.
  • The tumour has grown into the subserosa or it goes through the serosa. The cancer has also spread to 7 to 15 lymph nodes near the stomach.
  • The tumour has grown into nearby organs or areas. The cancer has also spread to 1 to 6 lymph nodes near the stomach.

Stage 3C

One of the following applies:

  • The tumour has grown into the subserosa or it goes through the serosa. The cancer has also spread to 16 or more lymph nodes near the stomach.
  • The tumour has grown into nearby organs or areas. The cancer has also spread to 7 or more lymph nodes near the stomach.

Stage 4

The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, bone, peritoneum or omentum. This is also called metastatic stomach cancer.

Recurrent stomach cancer

Recurrent stomach cancer means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it’s called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.

Gastroesophageal (GE) junction cancers

The GE junction is the area where the esophagus joins the stomach. Sometimes it’s hard for a doctor to know whether the cancer started in the lower end of the esophagus or the upper part of the stomach when cancer is in the GE junction. GE junction cancers are staged and treated as either esophageal cancer or stomach cancer based on where the tumour is.

The Siewert classification system may sometimes be used to stage GE junction tumours, but it is rarely used in Canada.

epithelium

A tissue made up of epithelial cells. It makes up the surface of the skin. It also lines hollow areas of the body (called cavities), glands and the passages of the respiratory, digestive, reproductive and urinary systems.

peritoneum

The membrane that lines the walls of the abdomen and pelvis (parietal peritoneum), and covers and supports most of the abdominal organs (visceral peritoneum).

omentum

A fold in the peritoneum (the membrane that lines the walls of the abdomen and pelvis) that covers and supports organs and blood vessels in the abdomen.

The greater omentum hangs down from the bottom of the stomach, covers the small intestine and attaches to the transverse colon (the middle section of the large intestine). The lesser omentum is attached to the top of the stomach and bottom of the liver.

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