First, cancer cells proliferate rapidly. Due to the rapid increase in the number, the original space can not accommodate so many cells, and the cells at the edge of the tumor are "squeezed" into the surrounding tissues.
Secondly, due to the particularity of chemical composition and structure on the surface of cancer cells, the adhesion between cancer cells is low, the connection is loose, and it is easy to separate from cancer blocks, which creates conditions for diffusion.
Third, cancer cells secrete special substances, which dissolve and destroy surrounding tissues and open channels for diffusion and metastasis.
Fourth, cancer cells contain a special substance that can promote thrombosis, so that cancer cells can adhere to the wall of blood vessels or other parts, and continue to grow after entering blood vessels, laying the foundation for blood transfer.
In addition to the above reasons, there may be some factors that people don't understand, and these factors complement each other. Generally speaking, poorly differentiated cancer cells have early metastasis, wide metastasis range and high malignancy; The differentiation is good and the degree of malignancy is low. Why do different patients with the same cancer have different names? This is related to the stage of illness and the patient's physical condition. When cancer is in its early stage, there is less chance of spread. If radical treatment can be carried out before metastasis and spread, the possibility of metastasis will be ruled out. If the treatment is carried out in the late stage, it will form a passive situation and it is impossible to prevent it. In addition, people who are healthy and have strong resistance to cancer may also have metastasis in the later stage, and the range of metastasis is limited. When the physical condition deteriorates and the resistance drops, the condition will deteriorate sharply and the cancer cells will spread like a dam break. ...