Gastric cancer is one of the most common malignant tumors, and the mortality rate of gastric cancer accounts for 25% of all malignant tumor deaths in China, which is the first among all kinds of cancer deaths. 80% of those found belong to the middle and late stages, so early detection and rationalized treatment are the keys to improve the survival rate. Early manifestations of gastric cancer: 1. Upper abdominal pain Most of the pain in early stage is hidden pain or discomfort, but in late stage, it can be severe pain. The pain is irregular and worsens after meals, but some patients have pain similar to ulcerative disease, which can be relieved by antacids. 2.Supra-abdominal fullness and discomfort. 3.Loss of appetite, aversion to greasy meat, but can still eat as usual when given favorite diet, or anorexia in advanced stage. 4.Pancreatic cancer can be manifested as the feeling of obstruction under the raphe when swallowing. 5.Anorexia, weight loss, progressive anemia, pyloric obstruction, persistent black stool, ascites, epigastric mass, cachexia and other symptoms may appear when the disease develops to advanced stage. The abdominal masses are mostly located in the upper abdomen and are hard (sometimes they may resemble the left lobe of liver, which can be easily mistaken as liver cancer or cirrhosis). 2. Metastatic manifestations: hard lymph nodes can be felt on the left clavicle; cancerous ascites; metastasis to liver, lung and ovary, etc. with corresponding symptoms and signs. Relevant examinations: 1. Barium meal examination of upper gastrointestinal tract: the positive rate can reach more than 90%, and the common ones are: ① filling defect; ② intracavitary niche shadow, ulcer diameter is usually greater than 2.5 cm, and crescent-shaped dark shadow is seen at the periphery, the edge is not agent, and the nearby mucosal folds are coarse, disrupted or disappeared; ③ stenosis and obstruction. In recent years, due to the improvement of X-ray examination method and the use of double photography method, microscopic lesions in the interstices of mucosal folds can be observed, thus most early gastric cancers can be detected. 2.Gastroscopy and gastric mucosal biopsy cytology examination: whether fiber gastroscopy or electronic gastroscopy is an important basis for the diagnosis of gastric cancer, and biopsy is the only and most direct index for the diagnosis of gastric cancer. 3.Abdominal CT, blood CEA, etc.