The incidence of lung cancer and death rates have increased dramatically in recent decades in all countries due to smoking and environmental pollution, including the burning of coal. This is also largely true in China. Given the extremely high mortality rate of lung cancer, with an average 5-year survival rate of less than 10%, early detection of lung cancer in order to strive for comprehensive treatment measures, mainly surgery, is the key to improve the 5-year survival rate. Lung cancer originates from the bronchial mucosa epithelium and is confined to the basement membrane. It is called carcinoma in situ and can grow into the bronchial lumen or/and adjacent lung tissues and can spread through lymphatic bloodstream or transbronchial metastasis. The growth rate and metastatic spread of carcinoma are related to the biological characteristics such as the histological type and differentiation degree of the carcinoma. Lung cancer that occurs in the bronchial mucosa epithelium is also called bronchopulmonary cancer. What we usually call lung cancer refers to malignant tumors from bronchial or bronchiolar epithelial cells, which account for 90-95% of malignant tumors in the lung parenchyma. The high incidence of lung cancer is in people, especially men, who are over 40 years old, who usually smoke up to one pack per day or more, and who have smoked for more than 20 years. This is one of the most important early features of lung cancer and a new discovery of experts at home and abroad in recent years. Hoarseness can occur after laryngitis, cold and acute bronchitis, thyroid surgery, pharyngeal surgery, improper vocalization, excessive speech or even heavy smoking and drinking. However, this type of hoarseness can usually be treated symptomatically or cured spontaneously with rest. The hoarseness caused by lung cancer, thyroid cancer and laryngeal cancer is completely different from the above type of hoarseness, especially lung cancer. Other early symptoms of lung pain, such as cough, chest pain and hemoptysis, lack characteristics, while hoarseness has certain specificity. According to statistics, about 20%-30% of lung cancer patients can have hoarseness at different stages of the disease, including early stage, and among them, central lung cancer can be as high as 40%. The pathology of hoarseness caused by lung cancer is that the cancer invades and compresses the nerves that govern the vocal cords, and this hoarseness often occurs suddenly, progresses rapidly, or even completely loses voice. 2.Fever Central lung cancer can produce obstructive pneumonia when it grows to semi-obstruction or total obstruction in the bronchial lumen. The fever is usually around 38℃, which can be easily reduced by anti-inflammatory treatment. However, if the obstructive lesion is not removed, pneumonia will reappear soon afterwards, forming recurrent pneumonia. Asymptomatic About 1/3 of lung cancer patients do not have any obvious early symptoms, so they can only rely on regular checkups for early detection of their lesions. Coughing up blood This is special in early lung cancer cases, such as central lung cancer, coughing up blood often occurs in the early and middle stages of the disease, the blood is small in quantity, bright red in quality or mixed with foam. The reason for this phenomenon is that the tumor surface is rich in blood vessels. Coughing damages the surface layer and causes the blood vessels to rupture. If there is occasionally more coughing blood, it is often recurrent or lasts for a longer period of time. 5.Cough The symptoms of lung cancer vary according to its location and functional damage. As the tumor grows on the large bronchial tubes and is highly irritating, it is easy to produce cough. However, the degree of coughing varies. About 50% of patients have irritating choking cough with no sputum or a little white foamy sputum. The quality of the sputum changes after secondary infection. People with a pre-existing chronic cough should be alerted if they notice a different nature of cough than usual. Patients with a high incidence of age should be seen early if the cough is ineffective after treatment or persists for a long time. Those with coughing up blood should be seen earlier. It is recommended that patients with the above symptoms should go to hospital for scientific examination, and lung cancer should be detected and treated as early as possible to relieve the pain and suffering of the disease.