Stomach cancer is one of the most prevalent cancers worldwide, with the incidence rate in men being 1.5-2.5 times higher than that in women. The incidence rate of gastric cancer increases significantly with age. For example, the incidence rate of gastric cancer in men is 70/100,000 at the age of 45-54, 145.7/100,000 at the 55-64 stage, and 264.3/100,000 at the age of 65-74. The peak age of incidence is between 50 and 80 years old. About 90% of gastric cancers are adenocarcinomas, which can be divided into two main types: 1. Intestinal type gastric cancer, which is better differentiated and more common in men and older patients. Intestinal type gastric cancer is predominant in high-risk regions, such as East Asia, Eastern Europe, Central and South America, and other regions. 2. Diffuse type gastric cancer, poorly differentiated, is more similar in incidence in males and females and more common in younger patients. Diffuse type gastric adenocarcinoma has a more uniform regional distribution and is closely related to blood type A and genetics. The incidence of intestinal type gastric cancer has decreased significantly in recent decades, driving down the overall incidence of gastric cancer, while the incidence of diffuse type gastric cancer is increasing. According to 2002 statistics, the number of gastric cancer cases per 100,000 men and 10.4 women worldwide was 22; the mortality rate was 16.3 per 100,000 men and 7.9 per 100,000 women. 900,000 new gastric cancer patients (600,000 men and 330,000 women) were estimated worldwide in 2002, while 700,000 people died of gastric cancer (450,000 men and 250,000 women). 250,000). In men, the incidence of stomach cancer is second only to lung cancer and prostate cancer, and the mortality rate is second only to lung cancer. Among women, stomach cancer has the fifth highest incidence rate, after breast, cervical, lung, and bowel cancers. Geographically, two-thirds of gastric cancers are found in Japan, China, Korea, parts of Central and South America, Eastern Europe and the Middle East, with lower incidence rates in North America, Australia and New Zealand, Northern Europe and India. In China, the geographical distribution of high incidence of gastric cancer shows “two peninsulas, one coastal line and one inland area”, which refers to Liaoning Peninsula, Shandong Peninsula, the coastal line from Fujian Province to Zhejiang Province, and inland cities such as Gansu Province, and the incidence rate in rural areas is higher than that in cities. The incidence and mortality rates of gastric cancer in developed countries have declined significantly in recent decades, with the annual mortality rate in the United States being about 22/100,000 in the 1950s and declining to less than 3.7/100,000 in the 1990s. Japan has also seen a significant decline in recent years, thanks to the adoption of barium X-ray or gastroscopic screening, which has greatly improved the detection rate of early gastric cancer.