China is a major country where gastric cancer occurs, accounting for nearly half of the new cases in the world each year. What is particularly scary is that the majority of these new cases are in the progressive stage, with early-stage gastric cancer accounting for less than 10%. In contrast, Japan and Korea, two other countries with high incidence of gastric cancer in the world, can account for 50%-60% of all new cases of gastric cancer. It can be deduced that if the detection window of gastric cancer in China could be moved forward earlier, the incidence rate could be doubled! With such a high incidence rate, but due to atypical symptoms or lack of attention by patients themselves, they are often at an advanced stage by the time they are diagnosed and lose the best opportunity for surgery. Therefore, it is very important to understand the epidemiology and clinical symptoms that may point to gastric cancer in order to improve the early diagnosis rate of gastric cancer. Epidemiology leading to the increase of gastric cancer incidence: 1. Dietary habits: gastric cancer is eaten out. All foods and drugs and compounds that destroy gastric mucosa and affect gastric mucosa repair are factors that cause loss of gastric mucosa barrier function, induce atypical hyperplasia and intestinal chemosis, and eventually lead to gastric cancer. Such foods include rough diet, pickled foods, tobacco and alcohol, moldy foods, etc. And most of the drugs and chemicals are damaging to gastric mucosa. 2. Helicobacter pylori: It is a common bacterium in the stomach and has a high infection rate in the Chinese population, which is related to the traditional food culture in which family and friends push and exchange glasses and have fun. Patients often ask, “Are tumors contagious?” Most of them don’t, but gastric cancer is exactly one of the small percentage of them. HP is very serious to damage the gastric mucosa and is an important factor leading to peptic ulcer and gastric cancer. Once HP is found, it should be paid high attention to kill it completely, and insist on examining the whole family together and implementing meal sharing system to avoid re-infection. 3.Environmental pollution: Although there is no definite evidence to prove which specific substance in soil water quality air causes the increase of stomach cancer incidence, the obvious regional differences still suggest that there is a relationship between stomach cancer and environmental pollution, if there are multiple cases of stomach cancer occurring around people, then we must be alert to whether it is the role of environmental factors. 4.Family history of tumor: If more than three people in close relatives have malignant tumor, or more than two people have malignant tumor, but the age of first occurrence is less than 40 years old, the existence of family history of tumor should be considered, and other family members should strengthen tumor screening efforts. People with epidemiology of stomach cancer occurrence should be classified as high risk group of stomach cancer. I should pay great attention to the traces of daily life and strengthen the examination in hospital. These traces include: 1. Presence of precancerous state: The so-called precancerous state refers to benign diseases that may develop into cancer, including gastric ulcer, atrophic gastritis, warty gastritis, etc. With such diseases, they should be treated promptly and gastroscopy should be done diligently to observe the changes. 2. Upper gastrointestinal bleeding: The first symptom of gastric cancer is often not obstruction, perforation, wasting, etc., but upper gastrointestinal bleeding. If patients find that their stool is black, they should not just let it go, but should immediately collect the black stool and send it to hospital for occult blood test. If it is positive, upper gastrointestinal bleeding should be highly suspected and the cause must be investigated. 3. Appetite change: Before weight change, stomach cancer will firstly affect the appetite of patients. If you find that your appetite suddenly deteriorates, or you don’t want to eat what you used to like, you should pay attention to it. Some patients mistakenly think that it is caused by the heat in the summer and do not pay attention to it until their weight drops rapidly, which is too late. Other symptoms such as low-grade fever, vomiting, wasting and abdominal distension often indicate advanced disease and possible complications. Therefore, high-risk people with precancerous status should go to the hospital immediately for gastroscopy and gastroscopy if there is upper gastrointestinal bleeding or changes in appetite due to an annual gastroscopy. Nowadays, gastroscopy technology is less painful and can be fully tolerated by general people.