In fact, gastric ulcer itself is a benign disease, in some cases the gastric acid “digests” the gastric mucosa, so that a gastric ulcer appears. The mucous membrane of the stomach is very capable of repairing and can generally renew a layer in 3 days, but if the damage is repeatedly repaired for a long time, it may activate the cells to produce mutations and thus a small percentage of people will develop gastric cancer. There have been different opinions on whether gastric ulcers can become cancerous or not. Although some people believe that the occurrence of gastric cancer has nothing to do with ulcers, it can be seen from clinical or pathological studies that there is a relationship between gastric ulcers and the occurrence of gastric cancer, but it cannot be accurately predicted. The cancer rate of gastric ulcer is reported to be about 5% in China, especially for patients with long history of gastric ulcer, large ulcer and middle-aged or above, the chance of complicating cancer is higher. The mucosal epithelium or glands at the edge of ulcer are eroded by gastric juice and erosion occurs, which is transformed into cancer under the chronic stimulation of repeated destruction and regeneration. So what symptoms should be alerted when previous history of gastric ulcer develops into gastric cancer? 1. Abdominal mass: Patients with gastric ulcer usually do not form abdominal mass, but if malignant transformation occurs, the ulcer will become larger and harder, and the mass can be touched in the left upper abdomen in advanced stage. This kind of mass caused by gastric cancer is hard in texture, nodular, not smooth, and painful when pressed. 2.Vomiting blood or black stool: The patient often vomits blood or has tarry stool in the near future, the fecal occult blood test result is consistently positive, and severe anemia occurs, all these phenomena indicate that the gastric ulcer may be maligning into gastric cancer. 3. Recurrent ulcers and ineffective gastric drugs: Gastric ulcers are prone to recurrent attacks, but the symptoms can be relieved after taking anti-ulcer drugs in general. After taking anti-ulcer drugs for a period of time, the effect becomes inconspicuous or even ineffective, and it should be suspected as a precursor of malignant transformation. 4, persistent pain at night: the pain of gastric ulcer is mostly manifested as vague pain in the upper abdomen, burning-like or dull pain, and the onset of pain is related to eating, generally appearing within 1-2 hours after meals, and gradually decreasing later. If the pain loses the above regularity and becomes irregular, or becomes persistent vague pain, or if the nature of the pain changes significantly than before, it should be alerted as a precursor of malignant change. 5.Loss of appetite and loss of appetite: If a patient with gastric ulcer has loss of appetite, nausea, vomiting, fever and progressive loss of appetite within a short period of time, there is a great possibility of malignant transformation into gastric cancer. Who else is the high-risk group of stomach cancer? How to detect it early? 1. People with family history of tumor. If one of the relatives in two or three generations has had digestive system tumor or other tumors, the chance of getting stomach cancer will be higher. The response is to do professional tumor screening about 10 years earlier than the minimum age of cancer members in the family. 2. People who have bad habits such as long-term smoking, drinking alcohol, and especially love to eat hot food, pickled and barbecued food, and high-salt food. These habits can cause more serious damage to the stomach and should be adjusted in time. The high incidence area of stomach cancer may be related to dietary habits and geographical environmental factors: the northwest area represented by Qinghai, Gansu and Ningxia, and the southeast coastal areas such as Jiangsu, Shanghai, Zhejiang and Fujian have higher incidence of stomach cancer. 3, are suffering from chronic atrophic gastritis, gastric ulcer, gastric polyp, residual gastritis, intestinal epithelial metaplasia, Helicobacter pylori infection, etc. for a long time, they will significantly increase the risk of gastric cancer.