Most stomach cancers start in the glandular cells in the mucous layer which coats the lining of your stomach, and are called adenocarcinomas.
There are 2 types of adenocarcinomas;
- Type 1 occurs in the lower stomach, close to your small intestine known as the duodenum. Type 1 is usually a result of a chronic infection with H. pylori bacterium, or a bad diet, or a combination of both.
- Type 2 occurs throughout your stomach and is more than likely a result of genetic factors. Type 2 is aggressive and is more likely to spread than type 1. Type 2 can spread through the stomach wall to your lymph nodes, and will eventually spread to your pancreas, liver and colon.
Although most stomach cancers are adenocarcinomas, there are other forms of the disease, including:
- Lymphomas – these are usually caused by an infection of H. pylori and can be cured if detected early enough.
- Carcinoid tumors – these account for a very small percentage of stomach cancers. Carcinoid tumors start in the hormone-producing cells in your stomach – they grow very slowly and do not spread to other parts of the body as frequently as the more common stomach cancers do.
- GIST’s (or gastrointestinal stromal tumors) – also account for a very small percentage of stomach cancers. They can be found anywhere in the digestive tract, but most are found in the stomach. GIST’s are not the same as other types of gastric cancers. They originate from different cells and require different treatment. GIST’s can be fatal in a short time because they spread through your body very quickly.