Lung cancer has become one of the leading causes of cancer deaths in humans. Each year, 1.3 million new lung cancer cases occur worldwide, while about 1.2 million people die from lung cancer. Today. The incidence of lung cancer is increasing year by year, and there are more and more young adults suffering from it. China is the number one country in lung cancer, with about 400,000 people diagnosed with lung cancer every year, and the incidence rate has reached 61.4 per 100,000. Compared with 30 years ago, the mortality rate of lung cancer in China has increased by 46.8%, and it is expected that by 2025, the number of people dying from lung cancer in China will be close to 1 million each year. The Lancet, the world’s leading medical journal, has analyzed that if the status quo of lung cancer prevention and control in China is not changed, the cumulative number of lung cancer deaths in China is expected to reach 18 million between 2003 and 2033, which is equivalent to the combined population of several small European countries. Understanding the common risk factors of lung cancer and preventing lung cancer at an early stage has become one of the important means to fight against lung cancer. Risk factors of lung cancer 1. Can smoking cause lung cancer? Can quitting smoking really prevent lung cancer from occurring? In order to prevent and control lung cancer, we must understand the dangers of smoking. Among every 100 patients diagnosed with lung cancer, 80-90 cases of lung cancer are related to smoking, and the earlier, longer and more heavily smoked, the greater the risk of developing lung cancer. Therefore, quitting smoking is the easiest and most feasible measure to prevent lung cancer. “Smoking is bad for your health”, but this slogan does not give much warning to the world. The current smoking rate of men in China is as high as 67%, and the smoking rate of young people and women is also increasing year by year, which deserves a good reflection. The human bronchial and fine bronchial surface is arranged with dense cilia, usually these cilia will continuously sweep the inhaled particles into the mucus, and through the sputum out, to achieve the purpose of self-purification. However, the chemicals in tobacco smoke gradually destroy these cilia and increase mucus production, leading to lung lesions and chronic diseases such as bronchitis. Apparently, smokers’ coughs are caused by an increase in phlegm due to damage to the cleansing function of the lungs. Some people believe that some long-term smokers have likewise lived to be over 90 years old and use this as a reason not to quit smoking. In fact, each person has a different genetic background and a different lifestyle, so the effects of smoking on the body are different, but you can’t take any chances because of this, after all, your own health is the most valuable. There are some smokers who smoke without inhaling and vomit after smoking to prevent lung cancer. However, the bronchus is an open airway, and no matter what kind of smoking method is used, more or less smoke will enter. In addition, this way of smoking because of the concentration of local smoke is too large, but more likely to stimulate the mouth and throat, the light can cause pharyngitis and oral ulcers, and the serious can lead to oral cancer and nasopharyngeal cancer and other diseases. In addition, there are some arguments that long-term smokers are more likely to develop cancer when they suddenly quit smoking. A study from the United Kingdom has provided a clear answer to this myth. The study conducted a comprehensive analysis of smoking, smoking cessation and lung cancer prevalence trends in the United Kingdom since 1950 and compared the results of two large studies from 1950 and 1990. The final finding was that even if smokers quit in middle age, they would reduce the risk of lung cancer later, and quitting before middle age would reduce the risk of tobacco-induced lung cancer by more than 90 percent. 2.Second-hand smoke is more terrible? If you can’t quit smoking temporarily, please don’t smoke in public places because inhaling second-hand smoke is also one of the important causes of lung cancer. Studies have shown that non-smoking women who inhale secondhand smoke because their husbands smoke (also known as passive smoking) have a 50% increased risk of developing lung cancer. In recent years, due to the increasing sophistication of cigarette production, the tobacco particles produced by smoking have become smaller and smaller. This allows smokers to reduce the discomfort caused by smoking such as sore throat and coughing, but on the other hand, it makes it more difficult for the cilia of the bronchi to capture these particles, and more tobacco particles reach the depths of the lungs with breathing, thus causing more harm. And the fine tobacco particles drift farther, causing more harm. Often, secondhand smoke comes not only from the smoke produced by the smoker’s exhalation, but more often from the burning cigarette, which is emitted directly into the atmosphere without being filtered by the filter, causing even greater tobacco harm. In summary, quitting smoking and refusing passive smoking is by far the most effective way to prevent lung cancer. What other factors should be avoided to prevent lung cancer? Although the occurrence of lung cancer is closely related to smoking, smoking is only one factor. While the number of smokers in China has not changed significantly over the past few years, the number of lung cancer cases has skyrocketed. A large part of the reason for this phenomenon is the pollution caused by urbanization, from industrial pollution, chemical pollution, pesticide pollution to automobile exhaust pollution, which, together with smoking, greatly increases the chances of people developing lung cancer. In addition, the incidence of lung cancer among women has been increasing very fast in recent years, which is not only due to atmospheric pollution, but also due to the carcinogenic effect of cooking fumes. Modern high-rise buildings are getting taller and taller, but the living environment is getting more and more limited, which makes it difficult to discharge cooking fumes in small and closed kitchens, and the local smoke concentration is higher. Therefore, in daily life, we should also try to reduce the generation of cooking fumes, reduce the use of frying, frying and other methods of cooking food. In addition, asbestos, nickel, chromium, arsenicals, dichloromethane, chromium compounds, nickel compounds, soot, tar, heating products of tobacco, radon and radon daughters produced during the decay of radioactive substances such as uranium and radium, ionizing radiation, microwave radiation, and long-term exposure and inhalation of dust can induce lung cancer. Therefore, strengthening the protection against occupational carcinogens such as radiation, asbestos and dust is also an important issue in lung cancer prevention. Lung cancer prevention How to prevent lung cancer “according to the map”? Cancer cells are part of the cells in our body, and everyone has cancer cells in their body, they are born with them. However, the major difference between cancer cells and normal cells is that they can suddenly become uncontrolled in their growth under the combined effect of various factors, and our body does not react to changes in our own cells as strongly and directly as external pathogens such as bacteria and viruses. Therefore, when lung cancer occurs, the body does not react much, but when the tumor grows to a certain level and causes pain, cough and other symptoms, the condition is actually very serious. This is the reason why most patients are already in advanced stage when lung cancer is diagnosed. Therefore, regular screening is more necessary for high-risk groups. Prevention of lung cancer is often based on tertiary prevention measures. Tertiary prevention is the division of prevention into three levels, i.e., primary, secondary and tertiary prevention. The first level of prevention, commonly referred to as “prevention before it happens”, is the first barrier to control lung cancer. The aforementioned measures of smoking control, environmental protection and occupational exposure prevention are actually the first level of prevention. The second level of prevention is also called “three early” prevention, that is, early detection, early diagnosis and early treatment. So how can we achieve the second level of prevention? In addition to regular checkups, we should also pay attention to some “alarm signals” of the body. Common “alarm signals” include: 1. irritating cough without obvious causes lasting 2 to 3 weeks, and ineffective with conventional cough suppression and anti-inflammatory treatment; 2. original chronic respiratory disease, but the nature of the cough has changed; 3. persistent or repeated blood in sputum in a short period of time with no other explanation; 4. recurrent episodes of the same site of pneumonia; 5, unexplained joint pain in the extremities or thickening of the terminal fingers (toes); 6, previous history of tuberculosis but recent changes in the morphology or nature of the tuberculosis lesions; 7, pleural effusion, especially a gradually increasing hemorrhagic pleural effusion. Of course, it is difficult to generalize here. For detailed lung cancer manifestations, please refer to the chapter of “Early Screening and Clinical Manifestations of Lung Cancer”. In conclusion, when there are uncomfortable changes in the body, it is important to seek timely medical consultation and strive to achieve the “three early stages”. As for tertiary prevention, it is a measure for diagnosed lung cancer patients, which includes two stages: prevention of disability and rehabilitation treatment. Tertiary prevention focuses on preventing recurrence and metastasis of lung cancer through comprehensive and effective treatment, focusing on rehabilitation, palliative and pain relief treatment, and providing physical, psychological, nutritional and exercise guidance to improve patients’ survival rate and quality of life.