The precursors of lung cancer may have symptoms such as cough, unexplained weight loss, hoarseness, hemoptysis and low fever. 1. Cough: Early stage of lung cancer will have unexplained cough, which will not get better even after anti-infection treatment, and is usually manifested as dry cough, and prolonged dry cough will lead to different degrees of chest pain and other symptoms. 2. Unexplained wasting: Lung cancer patients will often be accompanied by symptoms such as loss of appetite, generalized fatigue, and rapid weight loss in a short period of time. If patients have unexplained weight loss, they should pay attention to it. 3. Hoarseness: Early lung cancer may invade the recurrent laryngeal nerve, which may cause hoarseness and other symptoms. 4. Hemoptysis: Early lung cancer patients may cough unintentionally, and there will be dark-colored blood clots in the cough, and sometimes rotten tissues will be coughed out with sputum. 5. Low-grade fever: Early stage lung cancer patients may have recurrent low-grade fever, and the white blood cells are not obviously elevated. If the above symptoms appear, patients are recommended to go to regular hospitals for systematic examination and timely treatment to avoid delaying the condition.