Early stage gastric cancer is mostly asymptomatic or with only mild symptoms. When the clinical symptoms are obvious, the disease is already in advanced stage. Therefore, we should be very alert to the early symptoms of gastric cancer so as not to delay the diagnosis and treatment. Early manifestations Upper abdominal discomfort is the most common initial symptom of gastric cancer, about 80% of patients have this manifestation, which is similar to indigestion, and if abdominal pain occurs, it is generally light and irregular, and cannot be relieved after eating. These symptoms are often not taken seriously by patients and are easily mistaken for gastritis or ulcer disease when seeking medical attention. Therefore, middle-aged patients with the following conditions should be given further examination to avoid missing the diagnosis: (i) no previous history of gastric disease, but recent unexplained epigastric discomfort or pain that has been ineffective after treatment; (ii) previous history of gastric ulcer, and recent change in the regularity of epigastric pain with increasing severity. If the symptoms are relieved, but there is another episode within a short period of time, the possibility of gastric cancer should also be considered and further examination should be conducted in time. Nearly 50% of gastric cancer patients have obvious symptoms of loss of appetite or loss of appetite, and some of them restrict eating on their own because too much food will cause abdominal distension or pain. Unexplained anorexia and weight loss are probably the initial symptoms of early gastric cancer, which need to be taken seriously. Patients with early gastric cancer usually have no obvious positive signs, and most of them only have deep pressure pain in the upper abdomen in addition to weak general condition. Late stage manifestations When gastric cancer develops and expands, especially when the infiltration penetrates the plasma membrane and invades the pancreas, continuous severe pain may appear and radiates to the lower back. The absorption of toxins from the cancer may make the patient become increasingly thin, weak and anemic, and finally manifest as cachexia. When cancer grows up, obstruction symptoms may appear. Cancer of cardia or fundus may cause difficulty in swallowing, while cancer of gastric sinus may cause pyloric obstruction, and lumps may be found in the abdomen. When ulcers are formed on the surface of the cancer, blood vomiting and black stool will appear. As for metastases such as prerectal palpable mass, umbilical mass, enlarged supraclavicular lymph nodes and the appearance of ascites, they are more evidence of advanced gastric cancer.