In recent years, the incidence and mortality rate of lung cancer has been increasing significantly, and it has become the number one cancer in China, and the incidence rate of lung cancer is increasing rapidly at an average annual rate of 5%. More than a quarter of the annual deaths from cancer in China are lung cancer patients, and the situation of prevention and control is extremely serious. Research has confirmed that lung cancer is closely related to smoking, and about 80% of lung cancer is caused by smoking. In addition, the incidence of lung cancer is also showing a very obvious trend of low age, with the peak of incidence advanced by at least 10 years. The reason why lung cancer incidence has shown such a trend in recent years is related to the change of people’s living environment and lifestyle, among which factors such as lowering of smoking age, expansion of the smoking population and intensification of atmospheric pollution play the most prominent role.
I. Five common causes of lung cancer.
1.Smoking: According to a large amount of survey data, the etiology of lung cancer is very closely related to smoking paper cigarettes. The increase of lung cancer incidence is parallel to the increase of paper cigarette sales, which contains many carcinogenic substances such as benzo(a)pyrene. The incidence of lung cancer in smokers is 10 times higher than that of nonsmokers, and the incidence in heavy smokers is even higher, 20 times higher than that of nonsmokers. Among the clinically diagnosed lung cancer cases, those who smoke more than 20 paper cigarettes per day for more than 30 years account for more than 80%.
Passive smoking is also harmful. A large number of studies at home and abroad show that women whose husbands smoke have at least 5 to 10 times higher risk of lung cancer than those whose husbands do not smoke, and the more their husbands smoke and the longer they live with their husbands, the higher the risk, so the incidence of lung cancer in female patients is also significantly higher.
2.Atmospheric pollution: The high incidence of lung cancer in industrially developed countries, higher in urban than rural areas, higher in factories and mines than in residential areas, is mainly due to the pollution of the atmosphere with harmful substances such as benzo(a)pyrene carcinogenic hydrocarbons produced by burning oil, coal and internal combustion engines and asphalt highway dust in industrial and traffic developed areas. Atmospheric pollution and paper cigarette smoking may promote each other and play a synergistic role in the incidence of lung cancer.
3.Occupational factors: It has been recognized that long-term exposure to radioactive substances such as uranium, radium and their derivatives, carcinogenic hydrocarbons, arsenic, chromium, nickel, copper, mustard gas and other substances can induce lung cancer, mainly squamous and undifferentiated small cell carcinoma.
4.Chronic lung diseases: such as tuberculosis, silicosis, pneumoconiosis, etc. can coexist with lung cancer. The incidence of cancer in these cases is higher than that of normal people. In addition, chronic inflammation of lung bronchus and lung fiber scar lesion.
5. Intrinsic factors: such as family genetics, lowered immune function, metabolic activity and endocrine dysfunction may also play a role in promoting the development of lung cancer.
There are differences in the pathogenesis of lung cancer between smokers and non-smokers
Long-term smoking can lead to bronchial mucosal epithelial cell proliferation and phosphoepithelial growth, inducing squamous epithelial cancer or undifferentiated small cell carcinoma. Non-smokers can also develop lung cancer, but adenocarcinoma is more common.
Scientists from the Department of Biochemistry at the Weizmann Institute in Israel, through years of research on DNA repair mechanisms, noticed an important role of an enzyme called DNA repair enzyme (OGG1), which repairs DNA damage created by oxygen free radicals. The researchers tested the level of OGG1 activity with a simple new blood test. It was found that OGG1 activity was quite low in 40 percent of lung cancer patients, compared to 4 percent of the general population. It turns out that the large amount of oxygen radicals in smoke reduces the activity of OGG1, which directly leads to a much higher likelihood of cancer in smokers than in normal people. The researchers concluded that this simple blood test could be used to detect whether smokers were at high risk for developing lung cancer.
The results, published online May 13, 2008, in the British Journal of Cancer, show that when lung cells are exposed to cigarettes, the production of a specific protein, FANCD2, is slowed, resulting in lower levels. Whereas FANCD2 works to prevent cancer by repairing DNA damage or promoting defective cell suicide, low levels of FANCD2 can lead to DNA damage, which triggers cancer.
Recent studies have shown that, in terms of cancer development mechanism, lung cancers caused by smoking tend to follow the “K-ras pathway” and are mostly squamous and small cell cancers, while lung cancers caused by non-smoking tend to follow the “human epidermal growth factor (EGFR) pathway” and are mostly non-small cell lung cancers. Adenocarcinoma.
Prevention and treatment of lung cancer
Usually, cancer prevention is divided into three levels: primary prevention, which refers to the prevention of causes; secondary prevention, which refers to early detection, early diagnosis and early treatment to improve the cure rate and reduce the mortality rate; and tertiary prevention, which refers to reasonable and effective treatment for cancer patients to improve the quality of life and prolong the survival period. The same applies to the prevention of lung cancer.
1. Primary prevention.
To take preventive measures against specific cancer-causing and cancer-promoting factors such as chemical, physical and biological factors and pathogenic conditions inside and outside the body.
Pollution prevention and control Smoke, dust, chemical gases produced by industrialized production, and automobile exhaust pollute the atmosphere. Protecting the environment and improving the air quality of the atmosphere is the responsibility of government departments, but also requires the participation of the general public, as well as the supervision of public opinion. At the same time, the creation of a small environment is also very important, such as the use of environmentally friendly interior decoration materials, to strengthen the effective ventilation in the living room.
Smoking control It has been confirmed that smoking is the most important cause of lung cancer. The incidence and mortality rate of lung cancer has shown a very obvious downward trend in recent years, which shows that strict control of smoking is an effective measure to prevent and control lung cancer; to enhance awareness of lung cancer prevention and control, such as raising cigarette taxes and cigarette prices to keep people away from cigarettes, which is the most effective means to prevent lung cancer. This is the most effective means to prevent lung cancer. People at high risk of lung cancer should have annual CT examinations, which is an effective way to detect lung cancer at an early stage; strengthen publicity and carry out health education on “smoking is harmful to health” and “quitting smoking can prevent diseases and cancer”. Smoking is currently the single largest preventable cause of cancer.
Studies on lifestyle modification have confirmed the preventive effect of various fruits and green leafy vegetables on lung cancer. Balanced nutrition, eating foods high in protein, vitamins, fiber, and appropriate fats and calories. Do not eat moldy and spoiled food, minimize fried, fried, smoked and baked food, and eat seven to eight minutes of food per meal. Adhere to physical exercise, regular work and rest time, sleep enough.
Mental state is good. Bad emotions such as frustration, disappointment, depression and anger can negatively affect human endocrine system and immune system, and reduce the number of immune cells in the body, which can easily lead to cell mutation and induce cancer.
2.Secondary prevention.
From the clinical stage of lung cancer, the 5-year survival rate of early stage lung cancer patients after surgery is significantly higher than that of middle and late stage patients. Early detection, early diagnosis and early treatment occupy an important position in secondary prevention of lung cancer.
For the sudden appearance of symptoms such as irritating cough, blood in sputum, chest discomfort and chest pain, it is important to go to hospital for examination as early as possible. Regular medical checkups, chest X-ray and CT are necessary examinations, especially for people with family genetic tendency of lung cancer.
To detect lung cancer at an early stage, it is necessary to raise awareness and strengthen lung examination, especially for those who have smoked for more than 20 years, smoked more than 20 cigarettes per day on average and those who have long-term smoking history, family history of cancer or work in toxic or harmful environment over 40 years old, they should go to regular hospitals for CT examination every year, which is an effective way to detect lung cancer at an early stage. Those who have irritating dry cough, blood in sputum, chest pain, low fever and recurrent lung infections, which are not cured after active anti-inflammatory treatment, should pay attention to them and go to hospital for examination in time. As long as they can be detected early and treated regularly, 80% of stage I lung cancer can be cured clinically through surgery and obtain long-term survival for more than 5 years.
3.Tertiary prevention.
The goal is to prevent the deterioration of the disease and the occurrence of disability.
The treatment of lung cancer depends on clinical stage, with surgery as the main treatment in early stage (T1, 2 N0, 1 M0) and multidisciplinary standardized and comprehensive treatment in middle and late stage including radiotherapy, chemotherapy, Chinese medicine and molecular targeted therapy. Patients with a chance of cure are provided with radical treatment measures, and clinically, a comprehensive approach is mostly adopted to select a reasonable and optimal diagnosis and treatment plan. In clinical practice, we adopt a comprehensive approach and choose the best diagnosis and treatment plan, i.e. surgery to remove lung cancer and clear lymph nodes, supplemented by chemotherapy and radiotherapy, together with traditional Chinese medicine and immunotherapy to remove cancer cells from the body as early as possible. At the same time, we can restore the local function of the lung and all the functions of the body, promote recovery, improve the quality of life, and even return to society. Palliative treatment is provided to patients with no hope of cure to improve the quality of life and prolong survival.
Due to individual differences, the efficacy of the same treatment plan may vary greatly when used on patients with exactly the same disease. Therefore, the treatment of lung cancer is individualized and varies from person to person and from disease to disease, taking into account various factors such as the patient’s condition, physical condition, smoking history, gender, age, biological and molecular biological behavior of lung cancer. However, the prerequisite for developing individualized treatment plans is detailed examination and clear diagnosis, i.e., evidence-based medicine.
In terms of drug therapy, lung cancer with K-ras pathogenesis in smokers is not sensitive to chemotherapy drugs, and the efficiency of chemotherapy is only 30%-40%, and there are no corresponding targeted therapeutic drugs; while lung cancer with EGFR pathogenesis in nonsmokers has many drug options. growth factor receptor inhibitors”.
Researchers also believe that because nonsmokers have some novel pathological features of lung cancer, targeted therapies for their specific genetic loci have been successful, such as gene therapy for an “EML4-ALK gene” associated with lung cancer. With the exception of a very few clinical trials, the majority of healthcare providers still treat lung cancer in smokers and non-smokers as the same disease. U.S. researchers believe that traditional therapies are problematic and detrimental to non-smokers with lung cancer, given that the two types of lung cancer differ in anatomical features and in depth at the cellular and molecular levels, and in some respects are very different.
Although there are many approaches for lung cancer, surgery, chemotherapy, radiotherapy, the real treatment effect is far from people’s expectation. Early detection is the most critical way to improve the cure rate, because only early stage patients can get long-term survival. We are also advocating that for the younger generation, although they are very young, they should pay attention to their health status, actively quit smoking and should go for regular medical checkups.