1.Surgical removal of tumors is similar to the “bomb bunker”, the removal of the mass is equal to the mass is no longer. 2.But the ghosts inside the bunker have escaped. Even if the bunker is blown up, the ghosts can build new bunkers in other places. Cancer cells are like this, they like to run, thus some people will still have recurrence and metastasis after surgical removal of tumor. 3.The purpose of chemotherapy is to kill cancer cells that can run. If chemotherapy is administered before surgery, it can first kill the cancer cells inside the bunker, even if the cancer cells do not die, they cannot run even if they want to, so that they are sealed in the bunker, although the patient’s body resistance is low during surgery, the cancer cells cannot run, which can improve the effect of surgical resection of lumps. 4.Chemotherapy after surgery can kill the cancer cells that have already run outside the lump (bunker) to kill them, which can prevent recurrence. 5.So the difference between chemotherapy and no chemotherapy is that patients with chemotherapy after surgery are less prone to recurrence and metastasis, which can improve the cure rate.