Lung cancer is a very common malignant tumor of the respiratory system. Generally, when lung cancer reaches advanced stage, there is a possibility of severe pneumonia before death, as well as necrotic absorption of lung tumor causing elevated body temperature, that is, fever. However, it is not sure that all advanced lung cancer patients will have such fever. If it is not accompanied by obstructive pneumonia, the fever may not last long until the end of life. Usually, the most important manifestation before death is probably respiratory failure, because the lung tumor itself may also affect the respiratory function most. If lung cancer metastasizes to other parts of the body, such as to the liver and the skull, it will also trigger corresponding symptoms, such as ascites, right upper abdominal distension and pain, inability to eat, increased intracranial pressure, etc., which may cause organ failure and directly lead to death.