In recent years, the incidence and mortality rate of malignant tumors have increased rapidly with the intensification of population growth and population aging in China, the acceleration of modernization such as urban industrialization, environmental pollution and people’s poor lifestyles. According to the epidemiological survey of the Ministry of Health, the mortality rates of lung cancer, liver cancer, colorectal cancer, female breast cancer, bladder cancer and their composition ratios related to environment and lifestyle are on the rise, among which: lung cancer and female breast cancer have increased the most, by 465% and 96% respectively in the past 30 years.
At present, the mortality rate of lung cancer occupies the first place in cancer mortality, and has become one of the most common malignant tumors in the world that seriously endangers human health. The incidence of lung cancer, which is the leading cause of death from malignant tumors in China, will double by 2025, becoming one of the common diseases, and 1 million people will die from lung cancer every year. It can be seen that lung cancer is a great threat to human health.
The current situation of lung cancer in China is serious, but it does not mean that we do nothing. We don’t need to talk about lung cancer as some people often do, thinking that lung cancer is a death sentence once it is detected. In fact, it depends on the specific situation. The overall 5-year survival rate of lung cancer is only 14.1%, but the 5-year survival rate of stage I lung cancer patients is 60% after surgery, and the 5-year survival rate of stage 0 (adenocarcinoma in situ, which is mostly characterized by hairy glass changes) is over 90%, so lung cancer can be treated well through early detection and treatment.
On the other hand, lung cancer can be prevented by quitting smoking, improving living habits and eating a reasonable diet, which can greatly reduce the incidence of lung cancer.
Through proper understanding of lung cancer and reasonable choice of prevention and treatment methods, lung cancer can be kept away from us and achieve good treatment effects. Now, we would like to introduce the causative factors, susceptible groups, early detection, treatment and prevention of lung cancer, so that we can have a full understanding of lung cancer and prevent and detect it at an early stage.
I. Causal factors of lung cancer
1.Tobacco Hazard
Smoking is the main cause of lung cancer. Paper cigarette contains many carcinogenic substances such as benzo(a)pyrene, and long-term smoking can lead to bronchial mucous membrane epithelial cell proliferation and induce lung cancer. A large number of surveys in various countries have shown that the risk of lung cancer in smokers increases with the number, duration and type of cigarettes smoked. 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 have smoked more than 20 cigarettes a day for more than 30 years account for more than 80%. The harm of tobacco does not stop there, but also increases the incidence of esophageal cancer, laryngeal cancer, heart disease, stomach ulcers and other “second-hand smoke” hazards.
2.Environmental pollution
Industrial development produces exhaust gas, automobile exhaust, asphalt highway volatiles, etc., which also contain many hydrocarbon carcinogenic substances. The incidence rate of lung cancer in industrialized countries is higher than that in rural areas, and higher in factories and mines than in residential areas.
3.Occupational exposure
Long-term exposure to radioactive substances such as uranium radium and its derivatives, carcinogenic hydrocarbons, arsenic chromium nickel and other metals, coal tar, asphalt oil, asbestos, mustard gas and other substances can induce lung cancer.
4.Chronic diseases of the lung
Patients with tuberculosis, silicosis, pneumoconiosis and other underlying diseases have higher incidence of lung cancer than normal people because chronic inflammation and lung fiber scars occur in lung bronchus under the stimulation of long-term chronic adverse substances, which may cause squamous epithelial metaplasia or hyperplasia in the healing process.
5.Intrinsic factors in human body
Such as family genetic inheritance and endocrine dysfunction with lowered immune function may also play a role in promoting the development of lung cancer.
The susceptible groups of lung cancer
1.Smokers: Smokers inhale and exhale smoke containing a large amount of carcinogenic substances. Active smoking and passive smoking are equally dangerous, therefore, long-term smokers and those who work and live in the smoke around smokers for a long time are all high-risk groups for lung cancer, especially those with three high-risk factors: (male age ≥ 45 years and smoking index > 400 cigarettes/year).
2.People with occupational exposure: those who have more opportunities to contact carcinogenic substances such as radon gas, radioactive substances, asphalt, arsenic, chromium, coal tar, asbestos, etc. in their daily work.
3.People living in polluted environment: people living in areas and cities with heavy air and water pollution.
4.People with chronic lung diseases such as tuberculosis, silicosis and pneumoconiosis.
3.Checking and detection of lung cancer
1.Focus on early clinical manifestations of lung cancer
Lung cancer patients, especially early stage patients, are often asymptomatic and only have symptoms common to general respiratory diseases, which often lead to misdiagnosis and delayed diagnosis for most patients due to atypical and non-specific symptoms. Therefore, susceptible people, especially those with high-risk factors, should pay attention to the following early symptoms of lung cancer for early detection of lung cancer.
Cough: Lung cancer usually produces irritating cough as it grows on bronchopulmonary tissues, resulting in irritating respiratory symptoms. Patients aged 35 years or above, especially those who have frequent irritating dry cough of unknown willingness; have tuberculosis and chronic bronchitis, and have sudden change of the original cough pattern. Cough as an initial symptom in about 50- 60% of patients.
Hemoptysis: there will be a small amount of bleeding when the tumor inflammation causes tissue necrosis and capillary breakage, which is often mixed with sputum and appears intermittently or intermittently with blood in sputum, hemoptysis, hemoptysis, and the first sputum in the early morning is more common; about 30%-50%.
Chest pain: intermittent chest pain of uncertain location and uncertain relationship with respiration; accounting for 30-60%.
Chest tightness and shortness of breath: sudden progressive shortness of breath, chest tightness, chest X-ray with pleural effusion; 20%-50%.
Chest X-ray shows “inflammation of the lung”, which cannot be completely controlled by treatment, and the symptoms recur or worsen.
Symptoms caused by tumor metastasis: such as enlarged lymph nodes in the neck, hoarseness, pleural effusion, bone pain, etc., accounting for about 10%.
Fever: caused by obstruction of bronchus by tumor leading to obstructive pneumonia or cancerous fever, mostly low fever, which may improve after treatment, but often recurring.
Extra-pulmonary symptoms: such as unexplained joint and muscle intractable pain, gynecomastia, etc.
In summary, it is important to raise the alertness to these symptoms, especially the susceptible people should go to the hospital in time once they have similar conditions. Early lung cancer diagnosis plays a great role in the good or bad treatment effect.
2. Application of clinical screening techniques.
Clinical screening of lung cancer has started in 1950s, from X-ray light, sputum exfoliative cytology, to bronchoscopy, etc. There are not yet recognized screening means, but early diagnosis of lung cancer can be made clinically from the following aspects.
For high-risk groups, annual chest fluoroscopy or radiographic physical examination is recommended, and spiral CT scan should be performed when masses or shadows are detected.
For those with cough, sputum and blood in sputum, repeated sputum checks for cancer cells and/or bronchoscopy.
Those with lung nodules or shadows found on chest X-ray but negative on bronchoscopy can undergo CT localized puncture biopsy.
3.In addition, many new technologies have been clinically applied in recent years to achieve good results and improve the early diagnosis rate of lung cancer.
Spiral CT and low-dose spiral CT: It can accurately detect lesions smaller than 2-3mm, especially for small nodular lesions with a diameter of 15mm, which is significantly better than X-ray chest X-ray. Compared with surgery, the sensitivity of low-dose spiral CT to detect intra-pulmonary nodules ≤6mm is 60% and 95% for those >6mm, but for neoplastic lesions ≥6mm, the sensitivity reaches 100%. A multicenter International Early Lung Cancer Action Plan (I-ELCAP) study showed that 80% of lung cancers picked up by annual low-dose spiral CT were early-stage lung cancers (treatable lung cancers); therefore, it can be used for the diagnosis of early-stage lung cancers and curable-stage lung cancers, which is expected to improve the cure rate and prognosis.
Fluorescence bronchoscopy: Using laser-induced autofluorescence technology, early lung cancer shows fluorescence different from normal tissue for early diagnosis, which can determine the site of early invasive cancer, making it possible to increase the sensitivity of diagnosing precancerous lung cancer and carcinoma in situ by 1.5 to 6.3 times.
Sputum exfoliative cytology based on liquid-based cytology technique: This method has improved the methods of material collection, cell separation smear, background influence and cell structure observation. It greatly improves the detection rate and accuracy of cancer cells, and the diagnosis rate of lung cancer, especially central lung cancer, is significantly higher than that of the traditional smear method.
Breath gas detection: It has been found that there are several alkanes and benzene derivatives in the breath gas of lung cancer patients that are different from those of normal people, and the detection of these components by spectral analysis instruments can detect early lung cancer and correctly predict 71.1% of lung cancer patients and 66.7% of non-lung cancer patients.
Gene microarray and tumor marker detection: With the advantages of large amount of detection information, high accuracy, fast examination and high degree of automation, it can make accurate diagnosis without clinical manifestation of symptoms.
The application of new technologies in clinical practice will provide significant help for early diagnosis of lung cancer.
IV. Treatment of lung cancer
The treatment of lung cancer is a comprehensive treatment mainly based on surgery. as long as the stage of lung cancer is determined before stage II and some stage IIIa, and there is no definite contraindication, surgical resection should be considered. the 5-year survival rate of stage I lung cancer patients is 60%, and the 5-year survival rate of stage 0 can be over 90%. The earlier the lung cancer is, the better the treatment effect is. In recent years, significant progress has been made in the comprehensive treatment of lung cancer, which has greatly improved the survival rate of lung cancer. For example, the application of targeted lung cancer drugs such as ERSA and Bevacizumab, three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and neoadjuvant chemotherapy, surgery and radiotherapy have significantly improved the survival period and quality of life of lung cancer patients. In addition, immunotherapy and Chinese medicine play an important role in reducing patients’ reaction to radiotherapy and chemotherapy, improving the body’s resistance to disease, consolidating the therapeutic effect, and promoting and restoring the body’s function.
V. Active prevention of lung cancer
Lung cancer prevention is more important than treatment, because it is closely related to environment, smoking and bad living habits, so lung cancer can be prevented by the following aspects
1. Quit smoking: It is never too late for smokers to quit smoking, but the earlier the better! Quitting smoking makes the risk of lung cancer significantly lower, and the incidence of lung cancer starts to decrease after 5 to 10 years of quitting, and after fifteen years of stopping smoking, the chance of getting lung cancer is the same as that of non-smokers.
2.Stay away from occupational exposure
3.Healthy lifestyle habits: eat a reasonable diet, more vegetables and fruits rich in folic acid, vitamin E and coarse cereals. Eat less smoked food and no moldy food.
5, pay attention to environmental and living hygiene: reduce harmful compounds in the process of housing renovation and after; pay attention to pollution in the kitchen and strengthen kitchen ventilation
6.Participate in physical exercise regularly to avoid obesity
7.positive life attitude: cultivate optimistic and open-minded personality and life attitude.
Although lung cancer is a malignant tumor, it can be prevented through active measures such as quitting smoking. In addition, the combination of focusing on early symptoms and choosing appropriate clinical examination means can lead to early detection and diagnosis of lung cancer and early selection of treatment, which can achieve very good treatment results.