Swollen face is not a precursor of lung cancer, it may be related to other factors such as drinking a lot of water, allergies, nephritis and so on. And the precursors of lung cancer are cough and chest pain. There are many causes of swollen face, such as drinking a lot of water, allergic reaction caused by contacting allergic substances, nephritis, heart failure, nephrotic syndrome, facial trauma, hypothyroidism, etc., which are not precursors of lung cancer. When some patients suffer from oral diseases, they may also show swollen face, such as periodontitis, apical periodontitis, gingivitis, etc. Lung cancer is a kind of malignant tumor, the cause of which has not been completely clarified. Some lung cancer patients may have no precursor, but some others may have cough symptoms, which manifest as paroxysmal irritating cough with no or little sputum. With the progression of lung cancer, superior vena cava syndrome may appear, which manifests as symptoms such as swollen face. It is recommended that people with swollen face should consult doctor for examination so as to clarify the cause of the disease and then follow the doctor’s prescription for treatment. Those who are diagnosed with lung cancer need to adjust their mindset and actively cooperate with doctors to control the progress of the disease.