The TNM stage of gastric cancer is mainly based on characteristics, T represents the size of gastric cancer tumor, N represents whether there is distant lymph node metastasis, and M represents whether there is distant organ metastasis. According to different pathological types, gastric cancer is roughly divided into stages I-IV. Stages I and II are relatively early stages of gastric cancer, which can be treated well with surgery or post-operative radiotherapy or chemotherapy, and the cure rate is relatively high. Stages III and IV gastric cancer may be treated less effectively, some of them may lose the chance of surgery, or even can only be treated by palliative surgery or symptomatic supportive surgery, which is less effective, and the prognosis is relatively lower compared with stages I and II.