What are the common manifestations of lung cancer? 1. The most common symptom of early lung cancer is cough: the tumor in the lung stimulates the receptors in the lung causing cough. Because most lung cancer patients are smokers, this often leads them to believe that the cough is caused by smoking as before. Not all coughs in smokers are precursors to lung cancer, but they are at least abnormal. 2. Blood in sputum: If the primary focus has invaded the small blood vessels in the respiratory tract, blood will flow into the respiratory tract, and then blood spots will be seen in the mucous sputum coughed out, which is called blood in sputum. 3.Pneumonia: No matter the tumor is compressing the respiratory tract or directly blocking the respiratory tract, it will infect the lung tissues below the blockage, so it will produce obstructive pneumonia, and symptoms such as cough, thick sputum and fever will appear. It cannot be ignored at will. 4, other: weight loss, fever, chest pain, breathing difficulties, etc. The importance of insisting on annual physical examination Chest CT examination should be performed during physical examination, which can detect early lung cancer that cannot be detected by chest X-ray, so a chest CT examination should be done during annual physical examination, while chest X-ray often misses some early lung cancer. Blood sampling for lung tumor markers, if there is a significant increase in a certain value, it can also indicate possible lung tumors.