gastric ulcer: it can become cancerous, and the canceration rate is about 5%. The cause of canceration is that the mucosa at the edge of chronic ulcer is damaged and destroyed, and the body repeatedly proliferates and repairs it.

Gastritis: It can be divided into acute and chronic types according to the forms of its onset; According to the lesion site, it is divided into antritis and gastritis; According to the degree of lesion, it is divided into superficial and atrophic. In many gastritis, atrophic gastritis will evolve into gastric cancer. Although atrophic gastritis can be transformed into gastric cancer, it is very rare after all, and all of them are serious patients. Generally, it takes a decade or two or even longer to progress from superficial gastritis to atrophic gastritis and then to cancer.

gastric polyps: gastric polyps can be divided into pedicled polyps and sessile polyps. Pediceless polyps are more likely to become cancerous than pedicled polyps (2.5 times higher). Polyps with large volume have high canceration rate. Especially if the diameter of polyp is more than 3 cm, the canceration can reach 7%. After gastric polyps are found, they can be removed by fiberoptic gastroscope.

intestinal metaplasia: different organs have different tissues and cells. If you see the structure and cells of another tissue in one tissue, this "displacement" phenomenon is called "metaplasia". Intestinal gland epithelium is found on gastric mucosa, which is intestinal metaplasia. There are two types of intestinal metaplasia: small intestine type and large intestine type, among which large intestine type is closely related to gastric cancer. If the middle-aged and elderly people have large intestinal metaplasia accompanied by severe typical hyperplasia, if the effect of medical treatment is not obvious, gastroscopy should be done regularly. Once suspicious canceration is found, operation should be done as soon as possible.

atypical hyperplasia of gastric mucosa: it is closely related to gastric cancer. It is divided into mild, moderate and severe levels. Mild, generally do not need special treatment; Moderate, requiring regular review; Severe, suspected cancer, need close observation. If canceration is suspected or cannot be ruled out, or pathological examination is difficult to distinguish from cancer, most of the stomach should be removed to "nip in the bud".