East Asia (China, Japan and Korea) is the region with high incidence of gastric cancer, accounting for about 2/3 of patients worldwide, and more than 400,000 new cases are detected in China every year, accounting for 42% of the world. Due to the low rate of early diagnosis of gastric cancer, about 40% of the cases have already developed into advanced stage when diagnosed, and the rate of recurrence and metastasis after radical surgery is as high as 40% to 60%. Surgery is still the main treatment for gastric cancer, chemotherapy and radiotherapy also play an important role, and new methods such as biological therapy and gene therapy have been emphasized in recent years. In most regions, the 5-year relative survival rate is about 20%, while in Japan, the 5-year survival rate can reach 60% due to extensive early screening and treatment. Risk factors for gastric cancer include H. pylori, smoking, high-salt diet, and other dietary factors. Helicobacter pylori (Hp) Many gastric diseases are thought to be significantly associated with Hp infection. The incidence of gastric cancer increases 4-9 times after Hp infection, and 60% of gastric cancer patients have Hp infection. Hp infection has a strong correlation with the incidence of distal gastric cancer and a certain relationship with proximal gastric cancer. Smoking The risk of gastric cancer is increased by 50% to 60% in the smoking population. Globally, it is estimated that 11% of gastric malignancies are closely associated with smoking. Smoking reduces the levels of carotenoids and vitamin C, both of which are protective agents against cancer, and can often be combined with H. pylori infection, both of which contribute to the development of atrophic gastritis. It takes 20 years after smoking cessation for the risk of gastric cancer to drop to the normal level. Tobacco and tobacco smoke contain many carcinogens and carcinogenic substances, such as benzo(a)pyrene, dimethylnitrosamines, phenolic compounds, and radioactive elements. Other serious harmful substances include nicotine, carbon monoxide, and tobacco tar. The results of a meta-analysis by Tredaniel et al. in 1997 showed that the risk ratio of gastric cancer in smokers compared to nonsmokers was 1.5 to 1.6, and there was a dose-related relationship. Recent research has also found that tobacco smoke contains free radicals, which can destroy genetic genes, damage cell membranes and reduce immunity, and promote tissue cancer, these substances can be dissolved in saliva and swallowed into the stomach, and because of the increase in the amount and duration of smoking, the long-term effect and cause gastric cancer. A paired case-control study was conducted by Wei Yuehong et al. in China, which included 303 new cases of gastric cancer and 303 healthy controls from August 2003 to August 2004. The results found that the occurrence of gastric cancer tended to increase with longer years of smoking, greater daily smoking and more years of smoking packs. Factors such as smoking years > 30 years, smoking volume > 20 cigarettes per day and comprehensive index of smoking pack years > 20 showed a strong positive correlation with gastric cancer. In China, Liu Yunxia et al. conducted a meta-analysis of case-control studies and cohort studies on the relationship between smoking and gastric cancer in China in the past 10 years. The results found that the association between smoking and gastric cancer was statistically significant, i.e., smoking is one of the risk factors for gastric cancer. Analysis stratified by gender (male and female) revealed that smoking increased the risk of gastric cancer in men and the association between smoking and gastric cancer in women was not statistically significant. This suggests that the association between smoking and gastric cancer is gender-related, which is consistent with the current situation that there are fewer female smokers in the country. High-salt diet Salt is essential in daily diet, and the taste of dishes is only with salt. But some people are accustomed to put more salt and like to eat heavy dishes, what will be the effect on the body as a result? According to the latest medical research report, the body absorbs too much salt will not only cause high blood pressure, but also cause stomach cancer. Doctors advise that if the average person eats more than two teaspoons of salt a day, it is enough to endanger health, and long-term consumption of food containing too much salt is tantamount to chronic suicide. A study published in the American Journal of Epidemiology, “The Relationship Between Stomach Cancer and Salt Consumption,” found that stomach cancer mortality rates worldwide are highest in South Korea, followed by Japan and China, and that all three Asian countries are known for their high-salt diets, with many of them consuming more than 10 grams of salt daily. The researchers who wrote the report conducted a survey of the dietary habits of 220 stomach cancer patients and 700 non-stomach cancer patients, and found that eating too much food with high salt content increased the chances of developing stomach cancer. Data from the study also showed that people who ate foods high in salt more than twice a month were 1.8 times more likely to develop stomach cancer than normal people. In fact, more than a decade ago, the relationship between the amount of salt in the diet and human health was discussed internationally, and it was found that eating too much salt can damage the cells of the stomach lining. While the medical community has not explained in detail why salt damages stomach lining cells, studies have at least learned that Helicobacter pylori is prone to releasing a carcinogenic substance in salt-cured foods. For example, in salted fish and cured meat there is both a large amount of salt and also nitrite, a carcinogen, so people who eat more salted fish and cured meat have a particularly high chance of developing stomach cancer. Another survey of 24 countries also found that some countries that often use salt to store food have a relatively high chance of stomach cancer, including Chinese preserved foods, Korean kimchi and Japanese salted radish, all of which are typical of salt-cured foods. It has been found that salted foods such as pickled vegetables are most likely to release carcinogenic substances because they contain a large amount of nitrate, which can be automatically transformed into nitrite at room temperature or combined with normal bacteria in the mouth to form nitrite, and nitrite can be combined with certain nitrogenous compounds to form ammonium nitrite, which has been proven to be a strong The latter has been shown to be a strong carcinogen and has been shown to induce adenocarcinoma of the stomach in many animal studies as well as in human studies. Although a certain amount of nitrite is present in the normal gastric juice of human beings and is formed by the action of certain substances to form ammonium nitrite, this chemical process is limited under normal conditions and can be enhanced under conditions of acid deficiency. In addition, salt can cause damage to the gastric mucosa and lead to inflammation of the stomach, and chronic gastritis is an auxiliary cancer-promoting factor. Therefore, according to T.S. Lee, Associate Professor of Nutrition at the University of Hong Kong, the daily intake of salt should generally be five grams, and should not exceed 10 grams at most. A report shows that the incidence of stomach cancer among Japanese residents has shown a decreasing trend since 1955, which is related to the westernization of Japanese diet since 1949, especially the increased intake of dairy products. In addition, drinking soy milk also has a protective effect, as reported in scientific articles.