As to when can surgery be performed after preoperative radiotherapy for gastric cancer, the current evidence-based recommendations are generally 4-8 weeks, because if surgery is performed within a short period of time, there is a period of edema at the end of radiotherapy, especially around the tumor tissue and surrounding normal tissues, which makes it difficult to perform surgery and is not conducive to postoperative recovery, and the incidence of complications such as anastomotic fistula and infection is relatively higher. During the period of 4-8 weeks, the edema subsides and the tumor is fully retracted, which makes the surgery less difficult and facilitates the postoperative recovery. The 4-8 weeks period after radiotherapy, this period can also be followed by another chemotherapy, which can further shrink the tumor. However, as the evidence develops later, the time may be extended or shortened again, but in general, based on the experience in rectal cancer, extension is more likely. Nowadays, rectum is operated at about 6-12 weeks, and hospitalization 1-2 weeks before surgery is required to improve the examination, re-evaluate the lesion, assess the possibility of surgery, and provide a basis for the plan of surgery through CT and other imaging examinations.