The main causes and risk factors of lung cancer;
Smoking is considered to be the most important carcinogen of lung cancer. In Europe and America, the incidence of lung cancer
Smoking accounts for about 90%. In 1980s, smoking accounted for 70% ~ 80% of male lung cancer in Shanghai. About 30% of female lung cancer is attributed to smoking and passive smoking. The age at which you start smoking is an important factor. The earlier you start smoking, the greater the risk of lung cancer. The death rate of lung cancer in people who smoke for 60 years is about 100 times higher than that in people who smoke for 20 years. The smoke produced after cigarette ignition contains more than 3,000 kinds of toxic chemicals, the most important of which are nicotine, carbon monoxide, cyanide, various carcinogens, radioactive isotopes and heavy metal elements in cigarette tar. Carcinogens produced by tobacco combustion include benzopyrene, nitrosamine, β-naphthylamine, cadmium and radioactive polonium. There are also cancer-promoting substances such as phenolic compounds. The mortality rate of non-smoking women suffering from lung cancer due to their husbands' passive smoking is higher than that of non-smoking women (no passive smoking) 1~2 times. When smoking and occupational or environmental carcinogens have carcinogenic effects on people at the same time, the result is greater than the combined carcinogenic effects of individual factors, which is called synergistic effect. Smoking and drinking also play a synergistic carcinogenic role. If you smoke an average of 20 cigarettes a day, the risk of lung cancer is 20 times higher for smokers who have smoked for 20 years than for non-smokers. People who started smoking before the age of 20 died of lung cancer 28 times more than non-smokers.
Occupational causes of lung cancer: In 1970s, the incidence and mortality of lung cancer were extremely high in some industrial cities where factories were concentrated. At that time, some cities ranked first in various malignant tumors. At present, it is considered that occupational exposure to the following substances is related to the occurrence of lung cancer: asbestos, arsenic compounds, chromium compounds, nickel compounds, dichloromethyl ether, ionizing radiation, mustard gas and polycyclic aromatic hydrocarbons in soot, tar and oil. For example, the mortality rate of lung cancer among asbestos workers is 7 times higher than that of the general population, while the risk of smokers among asbestos workers is 50~90 times higher than that of the general population, which is caused by the synergistic effect of smoking and asbestos.
⑶ Environmental pollution such as air pollution: If industrial waste gas is not handled properly, it will pollute the environment and atmosphere inside and outside factories and mines. In addition, a lot of coal, diesel, gasoline, asphalt pavement and motor vehicles burned every day in cities will lead to air pollution in densely populated areas. The incidence of lung cancer in general cities is 10%, and about 25% of heavily polluted cities are caused by air pollution. In recent years, stone, paint, floor glue, plastic ornaments and adhesives used in indoor decoration have brought indoor pollution.
(4) Cooking oil fume and indoor fire pollute indoor air: When cooking, when the temperature in the oil pan is above 200 degrees Celsius, the oil used will change chemically, and the oil fume will volatilize with the boiling of the oil. The oil fume contains carcinogens such as heterocyclic hydrocarbons and benzopyrene. Cooking oil fume is a risk factor for non-smoking women and chefs to develop lung cancer, and it is also a threat to workers who often work in the kitchen. Commonly used fuels for indoor fire are firewood, firewood, coal, oil, gas and natural gas. When burning, the smoke and gas produced are harmful and carcinogenic.
5. Indoor radon pollution: Radon is a radioactive substance, which widely exists in natural soil, rocks and building materials. It is the product of the decay of uranium and radium. Radon isotopes and their decay products are called radon daughters. As long as there is radon, there will be daughters, and radon and its daughters will endanger people's health. Radon can enter the room through the foundation, cracks in buildings, joints in building materials and loose parts of pipes entering the room, and radon may also escape into the room in building materials. The standard of radon concentration in indoor air in China is 100 baker/cubic meter. Starting from 1994, our country investigated 1524 office buildings and rooms in 14 cities, and found that the radon content exceeded the standard, accounting for 6.8%, and the highest was 596 beck/m3. During the period of 1990, the monitoring of basement in Beijing showed that 2.5% indoor radon concentration exceeded 200 beck/m3. Internationally, it is believed that the death rate of lung cancer of people exposed to radon concentration of 300~500 beck/m3 is twice as high as that of people with normal exposure level. Some studies estimate that there are about 24,000 cases of radon-induced cancer in the United States every year. In the United States, the harm of radon is considered to be the second largest lung cancer factor after smoking. The world health organization estimates that 5%~ 15% of all lung cancer patients in various countries are caused by indoor radon exposure.
Other risk factors of lung cancer: previous lung diseases, such as tuberculosis, pneumonia, chronic bronchitis, emphysema, etc. However, compared with the above five factors, the previous disease history has less effect. The blood selenium content of residents in high incidence areas of lung cancer is low. Studies at home and abroad have proved that a certain amount of selenium can inhibit and prevent cancer. The study found that the intake of meat, eggs and bean products in the diet of a tin mine lung cancer patient in China was less.
(7) Under the influence of internal and external factors, the polygenic mutation of oncogenes and tumor suppressor genes in human body causes the cells to be damaged and repaired in multiple stages, which eventually leads to cancer. It is known that oncogene ras, myc, Rb and tumor suppressor gene p53 are related to the occurrence of lung cancer.
Common symptoms of lung cancer:
① Cough, mostly irritating cough. ② Blood in sputum, mostly bloodshot sputum. ③ Chest tightness, chest pain, mild symptoms and vague positioning. When cancer cells invade the pleura and chest wall, the pain is aggravated, and the position is clearer and more constant than before. (4) Diffuse alveolar lesions caused by shortness of breath, pneumonia, atelectasis, malignant pleural effusion and tumor obstruction can all be caused. (5) fever, obstructive pneumonia or cancer virus. ⑥ Patients with advanced stage may have obvious cachexia. ⑦ Others.
Prevention of lung cancer:
(1) Do not smoke and quit smoking: (1) Carry out health education among the masses in an organized and planned way on the harm of smoking to health and cancer prevention. Since primary school, smoking is harmful to health. Medical staff, school teachers, literary and sports workers, journalists and leading cadres at all levels should take the lead in not smoking and set an example for the masses. Health departments, education departments, news organizations and mass organizations should carry out publicity and education on the dangers of smoking. ④ Take measures to prohibit smoking in all public places. Since the 1960s, Britain, America and other countries have vigorously publicized the activities that smoking is harmful to health, which has reduced the smoking rate of the population by 1 ~ 2% every year. By the 1990s, the rising trend of lung cancer incidence in these countries had stopped or gradually declined. No matter how many years you smoke, whether you have lung cancer or not, no matter how old you are, it is good for you to make up your mind to quit smoking at once. After quitting smoking, the carcinogenic toxins deposited in your body will gradually decrease. If you are a patient, quitting smoking can consolidate the curative effect. Quitting smoking can restore your immune function, enhance your physical strength and prevent cancer and other diseases.
(2) Prevention of occupational lung cancer: (1) Government departments should supervise and manage industrial and mining enterprises. (2) Reform the production process, reduce dust and smoke, reduce the concentration of harmful substances in the environment, continuously improve the degree of automation, mechanization and sealing of production, and avoid or reduce the direct contact between producers and known carcinogenic factors. ③ Strengthen personal protection, pay attention to normal operation during production, change work clothes and take a bath after production, and don't take work clothes home. ④ Regularly monitor the concentration of harmful substances in the environment, which shall not exceed the national allowable standards, and take effective protective measures in time. ⑤ Regular physical examination. If occupational precancerous lesions or early cancer are found, they should be treated in time and separated from the occupational environment with carcinogenic factors.
⑶ Prevention of environmental pollution: 199 1 year, the State Council promulgated the Detailed Rules for the Prevention and Control of Air Pollution, which played an important role in preventing lung cancer and other related diseases. The main contents are as follows: ① People's governments, industrial and mining enterprises and construction projects should incorporate the prevention and control of air pollution into production, construction and technological transformation plans, and strengthen supervision and management. (2) The air pollution prevention and control facilities and specifications are qualified, and the construction project can be put into production or use. ③ Prevention and control of smoke pollution. (four) new residential areas should implement cogeneration or central heating, promote low-pollution combustion technology, and gradually limit the combustion of loose coal. (five) it is forbidden to build new construction projects that discharge waste gas and dust containing toxic substances in residential areas, and those that have been put into operation should be purified. ⑥ For special reasons, it is necessary to burn substances that produce toxic and harmful gases such as asphalt, linoleum, rubber, plastic and leather in densely populated areas, which need to be approved by the local environmental protection department and set up an incinerator for centralized incineration. When building construction needs to melt asphalt, the fixed melting device should be closed when used. ⑦ The environmental protection departments of governments at all levels should implement unified supervision and management on the prevention and control of exhaust pollution from motor vehicles and ships. Cars that exceed the pollution emission standards prescribed by the state shall not be manufactured, sold or imported. (8) Take legal responsibility for those who violate state regulations.
(4) Control indoor smoke pollution: (1) Chimneys should be set for indoor coal stoves and stoves to keep the stoves airtight. Chimneys should be cleaned frequently and kept unobstructed. ② Gradually use gas instead of coal for heating and cooking. (3) Keep the kitchen ventilated, install a range hood or exhaust fan in the kitchen, and turn on the range hood or exhaust fan at the same time of ignition. (4) When cooking, the temperature of the oil pan should not exceed 200 degrees, and the oil pan should not smoke. Use less frying and cooking, and use refined oil for cooking oil. ⑤ The living room and bedroom should be separated from the kitchen to prevent polluted kitchen air from entering other rooms. 6. Indoor decoration, decoration, the use of pollution-free materials, in order to prevent the decoration materials from emitting harmful substances to residents, after decoration, before living in ventilation 1 month.
5] Controlling indoor radon pollution: ① From the architectural point of view, a dense barrier should be built to prevent radon from infiltrating into the room, and a cement barrier without cracks and holes is usually enough to prevent radon from infiltrating. Good ventilation is also an important link to control radon pollution. (2) Before building construction, the foundation selection should be strictly carried out, and relevant departments should be invited to do radon detection when necessary, and then radon reduction measures should be taken. Pay attention to the radioactivity of building materials and choose qualified building materials. Three people think that when buying a house, we should first know whether the area where the house is located belongs to the area with high radon content in the stratum and avoid buying a house in such an area. ④ Choose building materials with low radioactive substance content as decoration materials. ⑤ Fill and seal the cracks on the floor and wall. ⑤ Use the basement as a living room or workplace. Be sure to monitor indoor radon concentration. If the radon concentration is too high, it should not be used as a living room or workplace.
[6] Diet prevention and chemical prevention. Ma Chang and other studies have confirmed that eating more green leafy vegetables and tomatoes has obvious protective effect on preventing lung cancer. Researchers have observed that lutein, lycopene, indole and other vegetable components in vegetables have anti-cancer effects on human body. Ziller and others found cruciferous vegetables (such as rape, cauliflower, cabbage, Chinese cabbage, cabbage, cauliflower, turnip, etc. ) has a more prominent protective effect on lung cancer. The research results of American Cancer Institute and Cancer Institute of China Academy of Medical Sciences are the same as above, and the protective effects of onion and garlic on lung cancer are also found. Its effective components may be carotenoids and their compounds. In the study of this mine, it is found that eating more tofu and eating meat and eggs in moderation also has a protective effect.
Increasing the intake of vegetables and fruits in food, especially foods rich in carotene, vitamin C, vitamin E, folic acid and trace element selenium, can reduce the incidence of lung cancer. High-fat, high-cholesterol diet and drinking alcohol will increase the risk of lung cancer.
Vitamin A can maintain the integrity of cell membrane, maintain the normal metabolism of epithelial tissue, block the process of cell carcinogenesis, accelerate the repair of nuclear DNA and regulate gene expression. Graham's research among multi-ethnic people in Hawaii found that those who consume less than 25,000 international units of vitamin A per month have a higher risk of lung squamous cell carcinoma than those who consume more than 6,543,800 international units per month.
Derivatives of vitamin A, carotene and carotenoids have attracted more attention in preventing lung cancer. Hunan Cancer Hospital 1989 reported that 1984 Viaminate (RI) and tretinoin (derivative of vitamin A) made in China were used in two mines in Hunan to treat moderate and severe atypical hyperplasia of sputum cells. After treatment, the general situation improved, and immunoglobulin IgA and IgM in blood increased. The incidence of lung cancer in the treatment group and the control group was 1 ~ 4, and the average grade of proliferating cells decreased, suggesting that this product has certain curative effect on chemical prevention.
Once you live a regular life, feel happy, combine work and rest, exercise, and increase your ability to prevent diseases and diseases.
(8) Residents above middle age should have regular physical examination: when there are symptoms such as irritating dry cough and bloodshot sputum, they should go to the hospital for examination in time. If someone in the family has lung cancer, other members should also pay attention to it and check it regularly.