How far is lung cancer from us? Lung cancer is the malignant tumor with the fastest growing incidence and mortality rate, and the most threatening to human health and life. Currently, the incidence and mortality rate of lung cancer is the first in men; in women, the incidence rate of lung cancer is second only to breast cancer, but the mortality rate is the first. Every year, there are about 1.2 million newly discovered lung cancer patients worldwide, and about 1.1 million people die from lung cancer, a number that exceeds the total number of deaths caused by breast cancer, colon cancer and prostate cancer. In China, the incidence rate of lung cancer in 2000 was 38.46/100,000 and 15.7/100,000 for men and women respectively, and the mortality rate was 33.21/100,000 and 13.45/100,000 respectively. Why do people get lung cancer? Smoking or passive smoking is the most important causative factor of lung cancer. 87% of lung cancer patients have a history of smoking, and the risk of dying from lung cancer increases 20 times if the average person smokes 40-60 cigarettes per day. Smokers who quit smoking for a period of time can reduce the risk of lung cancer. Air pollution is another causative factor of lung cancer. Air pollution can be caused by daily life such as household cooking, indoor decoration, coal burning in factories, oil and motor vehicle exhaust, etc. Polluted air is an important carcinogen because of the presence of aliphatic and aromatic carbohydrates, trace radioactive elements such as radon, metals and arsenicals. Long-term exposure to radioactive substances and occupational carcinogenic factors such as nickel, silver, chromium, cadmium, beryllium, cobalt and asbestos can also cause lung cancer. Old infarction of lung tissue, scar of trauma, metal foreign body and granuloma-like infection (such as tuberculosis) are all related to the occurrence of lung cancer. In addition, there is a strong relationship between lung cancer and family inheritance. People who have parents or brothers with lung cancer are two to three times more likely to develop the disease than the general population. How to detect lung cancer early? Due to the lack of sensitive nerve tissue in the lung parenchyma, people cannot sense that they are suffering from lung cancer at an early stage. In addition, the clinical symptoms of early lung cancer are not specific, unlike breast cancer, which will be associated with breast cancer once a lump is found in the breast. The symptoms such as cough, shortness of breath and blood in sputum are often ignored by people. Therefore, more than 60% of lung cancer patients are already in advanced stage when they come to hospital and lose the best time for treatment. Therefore, it is necessary for people to be vigilant, especially when the following conditions occur, they must pay enough attention to them and need to go to a specialized clinic for further examination if necessary: (1) Irritating cough lasting for 2-3 weeks and anti-inflammatory treatment is ineffective; or original chronic respiratory disease with a change in the nature of cough. (2) Persistent blood in the sputum with no other cause to explain. (3)Persistent chest pain of unknown origin. (4)Recurrent pneumonia at the same site, especially segmental pneumonia. (5)Incurable pulmonary abscess without toxic symptoms and large amount of pus sputum, with no significant efficacy of anti-inflammatory treatment. (6) Unexplained joint pain in the extremities and pestle-like fingers (toes). (7) Restricted emphysema, segmental or lobar pulmonary atelectasis, isolated round lesions and unilateral increased hilar shadow on X-ray chest film. (8) Pulmonary tuberculosis in the course of effective anti-TB treatment, the lesion has stabilized, and then a new lesion suddenly appears. (9) Patients with fast-growing hemorrhagic pleural effusion with heavy toxic symptoms. (10) Unexplained lymph node enlargement in the neck. Meanwhile, for those who are at high risk of lung cancer, they are those who have a long history of smoking, especially those who smoke more than one pack per day, those who are older than 45 years old, those who have a family history of lung cancer, and those who have long-term exposure to toxic gases. It is necessary to strengthen monitoring and pay attention to health checkups, and if the 10 symptoms mentioned above appear in the high-risk group, it is more important to pay enough attention to early detection of lesions.