The high incidence of lung cancer is attributed to environmental factors, occupational exposure, smoking, home cooking, inadequate intake of green vegetables, chronic respiratory diseases and genetic factors. Among them, smoking remains the most dangerous cancer-causing factor. For the high prevalence of lung cancer among non-smoking women in China, inner-city air pollution and previous history of lung disease are the reasons why they are not spared. The relationship between lung cancer and smoking is well known. Those who have smoked for more than 20 years, those who started smoking before the age of 20, and those who smoke more than 20 cigarettes a day (the so-called “320” group) are all very vulnerable to lung cancer. Among the hundreds of millions of smokers in China, the number of female and underage smokers is increasing year by year, which leads to an increase in the incidence of lung cancer in women and young and middle-aged people. It should be emphasized that heavy smokers are at high risk of lung cancer. Compared with non-smokers, heavy smokers are 5.7 times more likely to get lung cancer than non-smokers. Relevant studies so far have concluded that the relationship between smoking and cancer is characterized by the following 10 facts. 1. 30% of cancers can be attributed to smoking, especially lung cancer, laryngeal cancer, oral cancer, esophageal cancer, and also bladder cancer, pancreatic cancer and kidney cancer. The most fatal are lung cancer and pancreatic cancer. 2.Long-term smokers have 10-20 times higher incidence of lung cancer, 6-10 times higher incidence of laryngeal cancer, 2-3 times higher incidence of pancreatic cancer, 3 times higher incidence of bladder cancer, 4-10 times higher incidence of esophageal cancer than non-smokers, and the risk of blood cancers increases by 1.78 times. 3. If smokers smoke more than 25 cigarettes a day, 12% of them will develop lung cancer. 4.Some women who live with smokers are 6 times more likely to develop lung cancer than normal people. 5. 80% of the 1,000 lung cancer patients admitted to tumor hospitals are found to be long-term smokers. The risk of female smokers is more serious, which is 1.9 times higher than that of male smokers. 6. Smoking index (number of years of smoking × average number of cigarettes smoked per day) over 400 is a danger signal. If a young man starts smoking at the age of 15 and smokes a pack a day, he may get lung cancer before he reaches the age of 35-40. 7. 90% of lung cancer in most countries in the world is caused by smoking, and 35 people in every 100,000 people in China suffer from lung cancer. The earlier the age of smoking starts, the higher the incidence and mortality rate of lung cancer. If the lung cancer mortality rate of non-smokers is set at 1.00, the mortality rate of smokers who start smoking at the age of less than 15 years is 19.65, that of those aged 20-24 years is 10.08, and that of those aged 25 years or above is 4.08. The relative risk of cervical and ovarian cancers of women smokers is high. The former is 4.4 times higher than that of non-smokers and the latter is 2.8 times higher. The relative risk of cervical cancer among passive smokers in the family is 2.5 times higher than that of non-passive smokers. 9. Women who have smoked for more than 20 years have a 30% increased risk of breast cancer, and those who have smoked for more than 30 years have a 60% increased risk. The onset of cancer in smokers is 8 years earlier than in non-smokers. 10. Smokers undergo beneficial changes after quitting smoking, with lung cancer mortality rates declining over 5 years compared to the average smoker (one pack per day) or nearly as much as non-smokers. The incidence of oral, respiratory, and esophageal cancers drops to half the incidence of smokers. within 10 years, pre-cancerous cells are replaced by healthy cells. The incidence of lung cancer drops to roughly the same rate as nonsmokers after 10 or more years of smoking cessation. According to the World Health Organization, 85 to 90 percent of all deaths from lung cancer are attributable to smoking. Globally, nearly 6 million people die each year from smoking and secondhand smoke. Currently, there is a lack of public awareness of the health hazards caused by “secondhand smoke”. Surveys have confirmed that people who live with smokers for a long period of time are 25% more likely to develop lung cancer, and that being forced to inhale secondhand smoke for a long period of time also significantly increases the risk of lung cancer. Studies have also found that smoking-induced lung cancer is not sensitive to chemotherapy drugs, with an effective rate of only 30% to 40%, and is also not sensitive to molecularly targeted drugs.