All the symptoms of gastric cancer are actually not specific for the diagnosis of this disease, and the diagnosis of this disease is entirely based on the pathological results of gastroscopy and ultrasound gastroscopy to obtain biopsies to clarify. Gastroscopy is the main test used to detect gastric cancer. The test is needed when someone has certain risk factors or when signs and symptoms indicate the possible presence of the disease. The doctor passes a gastroscope through a thin, flexible, lighted tube with a small camera on the end. It is inserted through the mouth into the stomach, a procedure that reveals parts of the esophagus, stomach and small intestine. Gastroscopy shows an image of what looks like an ulcer, showing a mushroom-shaped or protruding mass that appears in a flattened, thickened area of mucosa. At this point, the doctor removes several pieces of tissue and sends them for pathological examination so that the diagnosis of the disease can be clarified. Endoscopic ultrasound is also a more widely performed means to examine gastric cancer. This instrument consists of a small transducer placed at the tip of the endoscope. It uses the same process of entering the stomach as gastroscopy. Once in the stomach, the transducer can be placed directly on the stomach wall where the cancer is located. This examines the stomach wall, as well as the nearby lymph nodes and other tissues outside the stomach. It is used to determine the depth of gastric cancer invasion, the presence of lymph node metastases near the stomach, and metastases to surrounding organs. This test can help to stage gastric cancer and guide the treatment plan after the diagnosis is confirmed. Gastroscopy and biopsy are currently used to confirm the diagnosis of gastric cancer. Gastroscopy can also be used as a screening tool for gastric cancer, which is beneficial for early diagnosis and early treatment of gastric cancer.