Gastroscopy can detect the lesions in the stomach and take the material, and pathology can find out whether there are cancer cells inside the lesions or what type of tumors, such as highly differentiated, moderately differentiated or low differentiated tumors, which is the gold standard for the diagnosis of gastric cancer. Gastroscopy can find out whether the tumor is located in the cardia, gastric body or sinus, which can determine different surgical procedures and the size of the tumor, and decide whether to perform total gastrectomy or major gastrectomy. Other examinations are auxiliary examinations, including barium meal, gastrointestinal tract imaging, and also abdominopelvic enhancement CT or MRI, which are used to evaluate the stage of gastric cancer. MRI can accurately evaluate T and N stages, and enhanced CT can also detect metastasis throughout the abdomen and pelvis, such as liver metastasis or pelvic implant metastasis or lymph node metastasis, etc.