Stomach cancer

The stomach is part of the upper gastrointestinal (GI) tract and the digestive system.

It is a hollow, muscular organ in the upper left part of the abdomen, located between the end of the oesophagus and the beginning of the small bowel (small intestine).

The stomach stores food that has been swallowed and assists with the absorption of some vitamins and minerals. The stomach also acts to pass the food and water into the rest of the digestive system, including the small and large bowel, where most of the processing of food takes place.

The different layers of tissue (known as the wall) in the stomach include:

• mucosa – it produces fluids that start breaking the food down
• submucosa – supports the mucosa and gives it blood to survive and take away any of the nutrients
• muscle layer (muscularis) – it helps to mash the food up and assists with pushing the food into the digestive system in a controlled way
• outer layer (serosa) – surrounds the layers of the stomach.

How the stomach works

Acidic (gastric) juices are released from glands in the stomach mucosa. These juices break food down into a thick fluid, which then moves into the small bowel. Nutrients from the food are absorbed into the bloodstream.

The waste matter moves into the large bowel (large intestine), where fluids are reabsorbed back into the body and the rest is passed out of the body as a bowel movement.

The exact causes of stomach cancers are unknown, but some factors may increase your risk.

Having one or more of these risk factors does not mean you will develop stomach cancer. 

Common risk factors for stomach cancer include:

• smoking
• high alcohol consumption
• a diet low in fresh fruit and vegetables
• infection with Helicobacter pylori (H. pylori), a type of bacteria found in the stomach
• low red blood cell levels (pernicious anaemia)
• chronic inflammation of the stomach (chronic gastritis)
• a personal or family history of stomach cancer
• inheriting a genetic change that causes the bowel disorders familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (HNPCC).

See your doctor if you are concerned about your risk factors or any symptoms you are experiencing.