The reason for chemotherapy before surgery, that is, the need for chemotherapy before surgery, is mainly determined by the stage of the tumor. Chemotherapy before surgery is also called neoadjuvant chemotherapy, which is mainly applied to middle and late stage tumors, because middle and late stage tumors are larger or more extensive, and accompanied by proximal or distant metastases, direct surgery cannot completely remove the tumor, or it is more traumatic to the patient’s body, and there is no way to achieve the ideal treatment effect. Chemotherapy before surgery has the following effects: First, it can reduce the size or scope of tumor, which can make the surgery more complete and make the surgery more effective and less traumatic, and also reduce the recurrence rate. Secondly, the blood vessels and lymphatic vessels supplying the tumor before the surgery have not been damaged by the surgery, which can improve the efficacy of chemotherapy later. Thirdly, the chemotherapy drug has formed a certain concentration in the body, which can reduce the chance of distant metastasis of tumor.