Disease analysis: The causes of lung cancer are still not completely clear, and a lot of data show that the risk factors of lung cancer include smoking (including second-hand smoke), stone wool, radon, arsenic, ionizing radiation, halogenated alkenes, polycyclic aromatic compounds, nickel and so on. Specifically as follows: (a) smoking Long-term smoking can lead to bronchial mucosal epithelial cell hyperplasia phosphatidic epithelium induced squamous epithelial carcinoma or undifferentiated small cell carcinoma non-smokers can also suffer from lung cancer but adenocarcinoma is more common. The burning of paper cigarettes releases carcinogenic substances. (Long-term exposure to radioactive substances such as uranium and radium and their derivatives, carcinogenic hydrocarbons, arsenic, chromium, nickel, copper, tin, iron, coal tar, asphalt, petroleum, asbestos, mustard gas and other substances can induce lung cancer, mainly squamous carcinoma and undifferentiated small cell carcinoma. (Chronic lung diseases such as tuberculosis, silicosis, pneumoconiosis, etc. can coexist with lung cancer, and the incidence rate of cancer in these cases is higher than that of normal people. In addition, chronic inflammation of lung bronchus and fibrous scarring lesions of lungs may cause squamous epithelial metaplasia or hyperplasia during the healing process, on the basis of which part of the cases can be developed into cancer. (e) Intrinsic factors, such as family heredity, reduced immune function, metabolic activity, endocrine dysfunction and so on. Therefore, lung inflammation will not be transformed into lung cancer.