Stomach cancer frequently develops over many years through a progression of chronic inflammation and precancerous changes within the stomach lining. One of the most important risk factors is Helicobacter pylori infection, which can often be identified and treated before more serious complications develop.

Additional factors such as smoking, high-salt diets, chronic gastritis, intestinal metaplasia, and family history may also increase risk. In some patients, surveillance endoscopy is recommended to monitor precancerous conditions and detect abnormalities at an earlier and more treatable stage.