Lung cancer! has become the number one killer of cancer. According to relevant data, the mortality rate of lung cancer tops the death list. Moreover, the longest latent period of lung cancer in human body can reach 20 years before it suddenly develops into an untreatable malignant tumor. With such a long latent period, wouldn’t it be great if it could be prevented? Here are the five common causes that trigger cancer! Five common causes of lung cancer: 1. Chronic lung diseases such as tuberculosis, silicosis and pneumoconiosis can coexist with lung cancer. The incidence of cancer in these cases is higher than normal people. In addition, chronic inflammation of lung bronchus and lung fiber scar lesions may cause squamous epithelial chemosis or hyperplasia during the healing process, on the basis of which some cases may develop into carcinomas. 2.The etiology of lung cancer is extremely closely related to paper smoking. (1) The increase in the incidence of lung cancer is parallel to the increase in the sale of paper cigarettes, which contain many carcinogenic substances such as benzo(a)pyrene. (2) Inhalation of paper cigarette smoke or application of tar in experimental animals can induce respiratory and skin cancer. (3) The incidence of lung cancer is 10 times higher in smokers than nonsmokers, and the incidence is even higher in heavy smokers, 20 times higher than nonsmokers. The incidence of lung cancer is also significantly higher in female patients. (4) Among the clinically diagnosed lung cancer cases, those who smoked more than 20 paper cigarettes per day for more than 30 years accounted for more than 80%. (5) In the past 20 – 30 years, the smoking situation in China is very serious, nearly 300 million people have smoked, the smoking rate of male adults is nearly 50%, nearly 5% of women, and there are also a lot of teenagers who smoke. 3.Occupational factors It is now recognized that long-term exposure to radioactive substances such as uranium, 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 and undifferentiated small cell carcinoma. 4.The degree of atmospheric pollution The incidence of lung cancer in industrially developed countries with atmospheric pollution is high, higher in urban than rural areas, and higher in factory and mining areas than residential areas, mainly due to the developed industrial and transportation areas, the burning of oil, coal and internal combustion engines, etc. and asphalt highway dust generated by hazardous substances such as carcinogenic hydrocarbons containing benzopyrene pollution of the atmosphere. The survey material shows that the incidence of lung cancer increases in areas with high concentration of benzo(a)pyrene in the atmosphere. Atmospheric pollution and paper cigarette smoking may play a synergistic role in promoting each other’s lung cancer incidence. 5.Personal factors Intrinsic factors such as family genetics, lowered immune function, metabolic activities and endocrine dysfunction may also play a role in promoting the incidence of lung cancer.