Gastric cancer is the second most common tumor after lung cancer in China, with 400,000 new cases and 300,000 deaths per year, accounting for 23.2% of all deaths due to cancer. The incidence ratio of stomach cancer is 3:1 between men and women, and the peak age of incidence is 50-60 years old, but in recent years, there is a trend of rejuvenation. What are the factors related to the occurrence of stomach cancer, which is so terrible? It is generally believed that the following factors are related to the occurrence of gastric cancer: 1. Environmental factors: The obvious difference of incidence rate between different countries and regions indicates that it is related to environmental factors, the most important of which is dietary factors. Excessive intake of salt or moldy food may be related to the occurrence of gastric cancer; 2. Genetic factors: If there are cases of gastric cancer in the family, the chance of other family members getting gastric cancer will increase. Some data show that stomach cancer occurs more often in people with blood type A than those with blood type O. Immunity factors: people with low immune function have higher incidence of stomach cancer, which may have some significance in the occurrence of stomach cancer due to immune dysfunction of the body and reduced immune supervision against cancer; 4. If left untreated, such lesions may develop into gastric cancer. Such as chronic atrophic gastritis, gastric polyps (higher cancer rate for those with diameter greater than 2cm), remnant stomach, gastric heterogeneous hyperplasia and interstitial changes, gastrointestinal chemosis, etc.; 5, bad habits: there are three aspects: first, long-term smoking and strong alcohol; second, long-term consumption of smoked, salted and moldy foods such as smoked fish, cured meat and sausages; third, obesity and long-term mental depression; 6, gastric Helicobacter pylori (HP) infection The risk of gastric cancer in HP-infected patients is 6 times higher than in HP-negative people. Nearly half of the newborn gastric cancer each year is related to H. pylori infection. Studies have confirmed that clearing H. pylori infection in the stomach can reduce the risk of precancerous lesions and gastric cancer by 40%. Since more than 70% of early gastric cancer is asymptomatic, early detection of gastric cancer is very difficult. The following phenomena should be noticed: irregular upper abdominal discomfort (about 80% of patients have this symptom), significant loss of appetite or loss of appetite (about 50% of gastric cancer patients have this symptom). In the advanced stage of the disease, weakness, back pain, nausea, vomiting and difficulty in eating caused by obstruction, vomiting blood and black stool caused by ulceration on the surface of the tumor, etc. may occur. Sometimes, patients with advanced disease may see epigastric mass, anemia, emaciation, ascites and other manifestations. If the above conditions occur, we should pay attention to them and go to hospital as soon as possible. Besides general screening, the main examination for gastric cancer is fiberoptic endoscopy, or gastroscopy for short, which is the most direct, accurate and effective way to diagnose gastric cancer. However, some patients may have concerns about gastroscopy, and the alternative examination is X-ray gas-barium double imaging, which can clearly show the outline of stomach, peristalsis, mucosal pattern, emptying time, whether there is filling defect and niche shadow, etc. The accuracy rate of the examination is close to 80%, but there are disadvantages that pathology cannot be obtained, and sometimes it is difficult to clarify benign and malignant, so gastroscopy is still needed for further clarification. Other auxiliary examinations include ultrasound (to understand whether there is metastasis in the surrounding substantial organs), CT of upper abdomen (to understand the location, size, invasion of gastric tumor, relationship with surrounding organs, possibility of surgery, etc.), tumor indexes CEA, CA724, CA199, CA125, CA50, etc. (play a reference role). How to treat the patients who have been diagnosed? There is a negative view that it is a malignant disease anyway, treatment is just a temporary extension of survival, so it is better to go home and eat something good. First of all, this view is negative. As mentioned above, if gastric cancer is detected early, the survival rate of 5 years with surgery can reach 90%-95%; while the cure rate of first and second stage gastric cancer is 40%-50%. In other words, the survival time of early stage lesions is about 50% if it is longer than five years. Therefore, if stomach cancer is found, it should be treated actively, which can not only prolong the survival period but also improve the quality of life. So what are the means to treat gastric cancer? First of all, surgical treatment has an important position in the treatment of gastric cancer, and it is the main treatment method that can achieve the purpose of cure. For those who cannot undergo radical resection, palliative resection of primary foci should be pursued according to patient’s specific conditions. For some early lesions such as submucosal lesions, gastroscopic mucosal resection (ESD) can be performed, and for early lesions that cannot be resected by endoscopy, laparoscopic minimally invasive treatment can be performed. In addition, according to the stage of gastric cancer, biological characteristics of the tumor and the patient’s body condition, chemotherapy, radiotherapy, Chinese herbal medicine and immunotherapy can be chosen. Of course, the disease needs to be treated, but it is more important to prevent it from the source to reduce the risk of the disease. We can’t choose the environment and heredity, but we can pay attention to exercise, cultivate good living habits, pay attention to dietary hygiene, avoid or reduce the intake of possible carcinogenic substances, and eat more vegetables and fruits rich in vitamin C. We can do it. For patients older than 40 years old with epigastric discomfort, gastroscopy should be done regularly, especially for men over 55 years old, regardless of whether they have discomfort or not, gastroscopy should be a routine medical checkup. For the pre-cancerous changes mentioned earlier, close follow-up is needed to facilitate early detection and timely treatment.