The full name of lung cancer is “primary bronchial lung cancer”. In recent years, its incidence and mortality rate have been increasing at an alarming rate. The incidence of lung cancer in China is mainly in urban areas, and the incidence rate of lung cancer is the first among men and the third among women. The cure rate of lung cancer is very low because lung cancer is still a kind of cancer that is difficult to be cured; the reason for this is that “the disease progresses quickly, and the detection, diagnosis and treatment are too late”. The countermeasures to cure lung cancer should be detection, early diagnosis and early treatment, among which the most crucial is early detection. Lung cancer is divided into two types, central lung cancer and peripheral lung cancer, according to the location of cancer growth. Early stage lung cancer refers to the first stage cancer in the international lung cancer staging, i.e. the cancer mass is less than 3 cm in diameter or more than 3 cm in diameter but local lymph nodes or distant metastases have not yet appeared. The common clinical symptoms of early stage lung cancer include cough, coughing blood, fever and chest pain. If one can be alert to these “clues” in the body and consult a doctor quickly, some early stage lung cancer can be detected in time. However, in reality, there are some early stage lung cancer cases with no clinical symptoms or even no clinical symptoms at all. Such early cases are often discovered unintentionally during medical checkups. Some clinical research data show that such asymptomatic early lung cancer is not rare, and its number of cases accounts for one-third of all early lung cancers. It has been found that most of the asymptomatic early lung cancers are peripheral type lung cancers. This kind of small cancer lump, which originates at the end of small bronchial tubes and is only about 2 cm in diameter, has slight stimulation to the mucous membrane of small bronchial tubes at the early stage of growth, and less or no symptoms such as coughing and coughing up blood, so people naturally do not easily notice it and will not actively seek medical consultation. When the cancer increases quickly or metastasizes to the second, third or even fourth stage, it is difficult to treat and the prognosis is not good. To detect asymptomatic early lung cancer, we can only start from raising awareness of prevention and attaching importance to regular cancer prevention checkups. The implementation of regular cancer prevention checkups focuses on the following three groups of people at high risk of lung cancer: (1) men, 45 years old or older, with a smoking history, especially those with a smoking index of 4OO or more: smoking index = years of smoking history × number of cigarettes smoked per day. For example, if a man has a 20-year smoking history and smokes 2O cigarettes per day, his smoking index is 20×20-400. Some survey and analysis data point out that the incidence of lung cancer in men over 45 years old with a smoking index greater than 4OO is 9.9 times higher than that of non-smokers of the same sex and age. (2) People in industrial and mining enterprises with a history of lung cancer epidemic who are in direct contact with raw materials and products for a long time: the carcinogens that have been confirmed to cause occupational lung cancer include asbestos, arsenic compounds, dichloromethyl ether, chromium compounds, nickel compounds, soot, tar, polycyclic aromatic hydrocarbons in petroleum, radioactive substances polluted in the mine air? Long-term exposure to these carcinogens can cause cancer. (3) Elderly people aged 60 to 80: This age group is at the peak of cancer incidence and is a high-risk group for many cancers, as well as for lung cancer. In addition, this age group has been exposed to passive smoking and environmental pollution for a long time, which is also one of the risk factors for lung cancer. People should learn some tumor knowledge and have some awareness of cancer prevention. If they belong to the high-risk group, they should take the initiative to have regular medical checkups for cancer prevention. The term “regular” here generally refers to 6 months. Some research studies have confirmed that relatively few early-stage lung cancers are detected in high-risk people who have annual checkups, while more patients are in the middle and late stages. Therefore, most experts suggest that “regular” should be set at 6 months. If high-risk people can take the initiative to have regular cancer checkups, they can detect asymptomatic early lung cancer in time and greatly improve the cure rate of lung cancer.