Every November is Lung Cancer Awareness Month, which is initiated by the Global Lung Cancer Alliance. The first lung cancer awareness survey conducted in 10 cities in China shows that nearly 80% of Chinese urban residents are not aware that lung cancer ranks as the number one killer on the cancer list, reflecting the low level of public awareness and understanding of lung cancer in China. In fact, the danger of lung cancer in China is staggering! By the beginning of this century, lung cancer had risen from the fourth to the first place in the ranking of malignant tumors. In urban areas, one out of every four deaths is due to cancer, and one out of every 34 deaths due to cancer is due to lung cancer. More seriously, with the large number of smokers in China, coupled with the accelerated aging of the population, increased industrialization and serious environmental pollution, the incidence and mortality rate of lung cancer will continue to climb rapidly. The World Health Organization (WHO) predicts that by 2025, China will have more than 1 million new lung cancer cases each year, making it the world’s number one lung cancer country.
Main causes of lung cancer
Lung cancer is formed by the malignant transformation of bronchial epithelial cells or alveolar epithelial cells of lung tissue, which further grows and expands to form cancerous tumors and can spread around or even throughout the body. The main causes of lung cancer are.
(1) Smoking: lung cancer is closely related to smoking, about 3/4 of lung cancer patients have important smoking history, tobacco contains tar and benzopyrene, especially in paper cigarette contains many carcinogenic substances, among which benzopyrene is the most important. Clinical data show that up to 90% of male lung cancer patients and 79% of female lung cancer patients are related to smoking. In recent years, the number of female lung cancer patients has increased, and some of them are not smokers, but the culprit was eventually found to be “second-hand smoke” and kitchen fumes.
(2) Air pollution: industrial exhaust and carcinogenic substances (mainly benzo(a)pyrene), coal and oil combustion, internal combustion engine exhaust, highway asphalt, etc. can pollute the atmosphere. According to statistics, the incidence of lung cancer is higher in industrially developed countries than in industrially backward countries; lung cancer is higher in urban than in rural areas, in large cities than in medium and small cities, in urban areas than in suburban areas, and in suburban areas than in distant suburbs, which may be related to industrial waste gas and carcinogenic substances (mainly benzopyrene).
(3) Occupational and physicochemical carcinogenic factors: At present, the more recognized ones are tobacco heating products, asbestos, chromium, chromate, beryllium, coal tar, asphalt, soot, mustard gas, dichloromethyl ether, chloromethyl ether, radioactive substances, uranium, radium and radon gas. Long-term exposure to the above substances can significantly increase the incidence of lung cancer.
(4) Chronic lung diseases: the incidence of lung cancer is higher in those with chronic bronchitis who smoke than in those who smoke without chronic bronchitis. In addition, chronic infections such as viral infections and fungal (aflatoxin) infections are also prone to complicate lung cancer.
(5) Diet and nutrition: Vitamins related to inhibiting the development of lung cancer include vitamin A, vitamin B, vitamin C and vitamin E.
Clinical manifestations of lung cancer
Early stage lung cancer symptoms
More than 1/3 of patients are asymptomatic. Early stage lung cancer lesions are small or located in areas that do not affect surrounding tissues much, so they can be completely asymptomatic. In particular, most peripheral lung cancers growing in the peripheral lung fields are asymptomatic, while those growing in the bronchial tubes (called central lung cancer) are more common. The symptoms are divided into pulmonary and extra-pulmonary symptoms.
(1) Pulmonary symptoms: ① irritating dry cough, coughing sputum may be present when secondary infection occurs. (2) Sputum blood. It is bright red or mixed with foamy sputum, which is due to the rich blood vessels on the surface of tumor, and coughing damages the surface layer, resulting in rupture of small blood vessels, usually with a small amount of sputum blood. ③Fever. The tumor grows in the bronchus, causing partial or complete obstruction of the lumen, resulting in obstructive pneumonia or pulmonary atelectasis, which may be accompanied by fever of about 38℃, and the fever will subside under anti-inflammatory treatment. ④ Chest pain is relatively rare.
(2) Extra-pulmonary symptoms (also called paraneoplastic syndrome): common ones such as pestle-like fingers (toes) or hypertrophy of bone joints, gynecomastia, etc.
Late stage manifestations of lung cancer
Metastases of different organs can appear in the late stage of lung cancer, which can cause corresponding symptoms and often bring great pain to patients and even threaten their lives. The common metastatic sites are as follows.
(1) Brain metastasis: headache (splitting headache), jet vomiting, diplopia, hemiplegia, mental symptoms, fainting, etc.
(2) Bone metastasis: severe pain and pathological fracture
(3) Liver metastasis: pain in the liver area, jaundice, ascites, and gastrointestinal symptoms.
(4) Spinal cord metastasis: common as retention of large and small stools and paraplegia.
(5) Mediastinal lymph node metastasis: paralysis of the recurrent laryngeal nerve, hoarseness, difficulty in eating, and mediastinal nerve palsy often occur.
(6) Superior vena cava syndrome: swelling of the face, head and neck and upper extremities, jugular vein anger, chest wall vein exposure, chest tightness and shortness of breath, etc.
(7) Esophageal compression: manifested as difficulty in swallowing.
(8) Pericardial metastasis: When a large amount of pericardial fluid occurs, there are often palpitations and shortness of breath, swelling of the lower extremities, hepatomegaly and decreased blood pressure resulting in cardiac compression.
(9) Pleural metastasis: causes chest pain, shortness of breath and dyspnea.
Examination means
Generally, the diagnosis can be confirmed in most patients by comprehensive judgment based on detailed medical history, physical examination and relevant auxiliary examinations. The main tests are: fluoroscopy, X-ray, chest computed tomography (CT), fiberoptic bronchoscopy, sputum cytology, percutaneous lung aspiration, EBUS aspiration, mediastinoscopy, bone imaging or emission tomography (ECT), positron emission tomography (PET), lung biopsy, tumor marker examination (CEA, NSE, SCC, etc.).
Comprehensive treatment of lung cancer
The treatment methods of lung cancer include the following: surgery, radiation therapy, chemotherapy, biological therapy and Chinese herbal medicine and other treatments. As lung cancer is a systemic disease, comprehensive treatment should be adopted according to different tissue types, disease stages and general conditions of the patient when choosing the treatment plan. Various clinical types and stages of the disease should adopt different comprehensive treatment plans. Common tissue types of lung cancer mainly include squamous cell carcinoma, adenocarcinoma, small cell carcinoma and large cell carcinoma. The treatment is complex and advocates individualized and multidisciplinary treatment, please consult your doctor for details.
Prevention
Lung cancer is poorly treated; therefore, prevention is the key to preventing lung cancer.
Primary prevention.
Smoking cessation campaigns. If smoking were ever banned, about 85% of lung cancers would be prevented. As individuals, not smoking, avoiding passive smoking, reducing air pollution in the kitchen, and improving indoor and outdoor air quality are the main ways to prevent lung cancer. Some smokers suffer from lung disease because of smoking and want to quit, but they worry that it is too late. Recently, scientific studies in the United States and Canada have given these smokers a piece of mind when they try to quit. Researchers at Johns Hopkins University and their team of researchers in the U.S. and Canada have been working on a study of the effects of smoking on lung disease. Hopkins researchers and their Canadian colleagues reported in the American Journal of Internal Medicine that they found that middle-aged people who quit smoking, even if they smoked heavily, were able to reduce their mortality rate by nearly half compared to those who smoked all the time.
Secondary prevention.
Chemoprevention to stop lung cancer in people at high risk of developing lung cancer; high-risk groups are defined as those with a smoking index >400 (years of smoking X number of cigarettes smoked per day), 45 years of age or older, and a family history of tumors; research on this is continuing.
Tertiary prevention.
Regular screening of people at high risk of developing lung cancer for early detection of lung cancer.