Clinically, the survival of patients with different cancer types varies greatly, and the survival of the same cancer type and different patients can also vary greatly. Therefore, the prediction of patient’s survival must be based on the actual situation of the patient to be meaningful. At present, it is mainly based on the following points: 1. the tumor type and stage of the patient The most important characteristic of cancer cells is that they grow fast, uncontrolled and can metastasize, and their growth rate far exceeds that of normal tissues of human body, often causing death soon due to compression, infiltration and access to normal nutrition of human body. The malignancy of cancer is directly related to the differentiation degree of the cells from which the growing tissue originates. Tumors with high degree of differentiation have low malignancy and late metastasis due to slow growth of cancer cells, while those with low degree of differentiation have high malignancy and early metastasis. For example, among lung cancers, small cell lung cancer has the worst prognosis and is prone to early brain, liver and bone metastasis, while squamous carcinoma generally has slower growth, late metastasis and higher 5-year survival rate. Therefore, the “good” and “bad” tumor cells determine the growth rate, metastasis rate and treatment effect of tumor, and also determine the life span of patients. In addition, early staged tumors are treated thoroughly and have a better prognosis, while late staged tumors are mostly treated palliatively and the invaded organs are prone to functional damage and have a very poor prognosis. 2. Treatment To cure cancer, the primary prerequisite is to completely kill the malignant tumor cells, so the choice of treatment is crucial. In clinical practice, there are many patients who believe in partial prescriptions or ancestral secret recipes, or fear surgery and radiotherapy after cancer discovery, and then go to small clinics or self-treat haphazardly until their condition worsens, which undoubtedly delays the treatment and the treatment effect is certainly not ideal. In addition, because of some underlying diseases of patients themselves, radical treatment cannot be carried out or the intensity of treatment is not enough, and the treatment effect will also be greatly reduced. The cancer of what grows cannot win the day, but the choice of what kind of treatment depends entirely on the patient. 3. general condition, cachexia Every patient will be given a general condition score (KPS) by the doctor upon admission, which is one of the reference indicators for the selection of many treatments. A number of studies have shown that for patients with advanced malignancies, KPS has been repeatedly shown to correlate significantly with survival, i.e., the better the general condition, the longer the survival. In contrast, cachexia, including dyspnea, outlook, fatigue, pain, weakness, anorexia, agitation and weight loss, as well as some hematological indicators (WBC>11×109 /L and Lym%<12%, low peripheral blood ALB, high LDH values, etc.), can be important independent factors in assessing the prognosis of patients with advanced disease.