Lung cancer does not have any special symptoms in the early stage, but only symptoms common to general respiratory diseases, such as cough, coughing blood, low fever, chest pain and tightness, so it is easy to be ignored. Specific manifestations of common symptoms of early lung cancer: 1. Cough. As lung cancer grows on bronchopulmonary tissues, it usually produces irritating cough due to respiratory tract irritation symptoms. If patients have a long-term cough that cannot be cured, it is recommended to have a comprehensive examination to avoid delay. 2.Low fever. After the tumor blocks the bronchus, there are often obstructive lung lobes present, the degree of which varies. In mild cases, there is only low fever, while in severe cases, there is high fever, which can temporarily improve after medication, but will recur soon. So patients with long-term low fever should not be careless and go to the hospital for examination as soon as possible. 3. Chest distension and pain. Early stage of lung cancer chest pain is mild, mainly manifested as boring pain, hidden pain, the location is not certain, and the relationship with breathing is not certain. If the distension pain continues to occur, it indicates that the cancer may involve the pleura. 4. Sputum and blood. When the tumor causes tissue necrosis and capillary breakage, there will be a small amount of bleeding, which is often mixed with sputum and appears intermittently or intermittently. Many patients with lung cancer are diagnosed with sputum and blood.