Many lung cancer patients are found at a late stage and doctors are helpless. In order to detect and treat lung cancer at an early stage, the proportion of screening and early diagnosis for high-risk groups should be emphasized. Early symptoms of lung cancer patients mainly include cough, blood in sputum, fever and chest pain, which can easily be considered as “lung inflammation” or “tuberculosis”, and should be investigated in hospitals as early as possible. Long-term smokers: Be wary of the three “20s” For smokers, there are three “20s” to be wary of: those who have smoked for more than 20 years, those who started smoking under the age of 20, and those who smoke more than 20 cigarettes a day. Any one of the three “20s” is very likely to get lung cancer. In addition, some people have a habit of smoking one cigarette after another, a cigarette is too short to be thrown away, others smoke very deep, most of the smoke is inhaled into the lungs, and some people have chronic bronchitis, but still “insist” on smoking, these behaviors are very harmful. I would also like to emphasize three words about quitting smoking, the first is that it is never too late to quit smoking, the second is that the sooner you quit, the better, and the third is that you must insist on quitting completely.