Liquefaction inside the tumor indicates that the tumor cells are necrotic or the treatment is effective. 1. Tumor cell necrosis, for tumors without treatment, in the process of rapid tumor enlargement, the internal tumor cells will be necrotic due to hypoxia and ischemia because of insufficient nutrients and oxygen supply, which will finally be manifested as internal liquefaction. 2. Effective treatment, if the patient has no liquefaction before treatment, but internal liquefaction occurs after radiotherapy, chemotherapy and other treatments, it may be caused by necrosis of tumor tissues, which mostly indicates that the current treatment plan is effective; even if the volume of the tumor remains unchanged, as long as it is necrotic or inactive, it is generally considered that the condition has been relieved.