Types of stomach cancer

Stomach cancers are classified by the cell they start from and, for the main type, by how they look under the microscope. The type guides treatment.

Adenocarcinoma (about 90 to 95 percent) Starts in the glandular cells of the stomach lining. It has two important subtypes.

• Intestinal type: more common, linked to H. pylori, diet and chronic inflammation; often arises in older adults.
• Diffuse type: tends to occur in younger people, can run in families (including CDH1 gene changes) and spreads within the stomach wall, making it harder to detect.

By location

• Cardia cancer: at the junction with the food pipe, linked to reflux and obesity.
• Non-cardia cancer: in the body and lower stomach, linked more to H. pylori and diet.

Less common types

• Gastrointestinal stromal tumor (GIST): starts in the stomach wall's special pacemaker cells; treated with specific targeted medicines.
• Lymphoma: cancer of immune tissue in the stomach wall; some early cases linked to H. pylori respond to antibiotics.
• Neuroendocrine tumors: from hormone-producing cells; behavior varies from slow to aggressive.
• Squamous cell carcinoma and others: rare.