What are the types of stomach cancer?

Most people with stomach cancer have a type called adenocarcinoma (A-deh-noh-KAR-sih-NOH-muh). As many as 9 out of every 10 people with stomach cancer have adenocarcinoma.

Adenocarcinoma is a kind of cancer that starts in the glandular tissue that lines organs. This kind of tissue makes mucus, digestive juices, and other fluids.

In stomach cancer, adenocarcinoma starts in the tissues that make up the stomach lining. There are 3 types of adenocarcinoma:

Non-cardia (distal) stomach cancer

This type of stomach cancer is linked to inflammation (swelling) and irritation of the stomach. It’s often caused by an infection with the bacterium Helicobacter pylori.

Proximal stomach cancer

This type of stomach cancer tends to start in people who are obese or have gastroesophageal reflux disease (GERD).

Diffuse stomach cancer

This is often a more aggressive type of stomach cancer. We look for the type of cancer cells and how they behave, instead of the location in the stomach. Diffuse stomach cancer grows quickly in the cells of the stomach wall. It does not form a mass or a tumor, so it’s hard to diagnose. Often, it affects younger people with a family history of stomach cancer or a related genetic syndrome, hereditary diffuse gastric cancer.

Less common types of gastric cancer

Lymphoma starts in immune cells in the wall of the stomach.

Gastrointestinal stromal tumors (GIST) start in stomach muscle or connective tissue. GIST starts in special cells in the wall of the stomach called interstitial cells of Cajal.

Carcinoid tumors start in stomach cells that make hormones. They’re a type of neuroendocrine tumor and often do not spread.