Lung cancer brain metastasis without treatment has a five-year survival rate of less than 5%, and the specific survival time should be analyzed with the condition. Lung cancer is a malignant tumor caused by heredity, smoking, gene mutation and other factors. When the disease develops to the late stage, multiple metastases can occur, such as brain metastasis, at this time, dizziness, headache, nausea and vomiting, epilepsy and other symptoms can occur. The main treatment methods in this period are radiotherapy, chemotherapy, targeted therapy, immunotherapy and other therapies. The purpose of treatment in this period is to prolong the survival time and improve the quality of life. After active treatment, patients with advanced lung cancer can obtain a five-year survival rate of about 5%, but if not treated in time, the five-year survival rate will be less than 5%.