Generally speaking, there are no specific clinical symptoms in the early stage of respiratory tract cancer, and only the symptoms common to respiratory system diseases appear. The common respiratory symptoms of respiratory tract cancer in clinic are irritating cough, blood in sputum, and chest pain. For central lung cancer, the tumor grows closer to the large airways, in which case irritating cough is likely to occur. If the tumor grows close to capillaries or there are capillaries in the tumor, blood in sputum or coughing up blood will occur easily. If the tumor grows on the chest wall, it is easy to produce the symptom of chest pain. Bronchial cancer stage I may also have systemic symptoms, such as emaciation, fatigue, obvious weight loss, loss of appetite and so on. Therefore, when the above respiratory symptoms and systemic symptoms occur, do not take them lightly and go to the respiratory department of regular hospitals in time for further examination to make a clear diagnosis.