Lung cancer, also known as primary bronchopulmonary cancer, is a malignant tumor that grows on the bronchial mucosa or alveoli. It is one of the major malignant tumors that seriously threaten human survival. In recent years, its incidence and mortality rate have been increasing at an alarming rate, with men significantly more than women, and the high incidence age is 40-60 years old. It is generally believed that the increased incidence of lung cancer is related to epidemiological factors. Smoking, industrial exhaust and atmospheric pollution are the main causative factors of lung cancer. The main pathogenic substances associated with lung cancer in industry are asbestos, radioactive substances, arsenic, chromate, nickel, and coal tar and petroleum products. Lung cancer has a high degree of malignancy and poor prognosis. About 80% of patients die within one year after definite diagnosis, and the median survival is about 6 months, including 4-9 months for adenocarcinoma, 5 months for small cell carcinoma, and 7-8 months for squamous carcinoma. The overall 5-year survival rate of lung cancer patients is only 5-10%. Therefore, early detection of lung cancer and striving to adopt comprehensive treatment measures mainly surgery as soon as possible is the key to improve the 5-year survival rate. Common early symptoms of lung cancer include: (1) cough Mostly dry cough with little or no sputum, but with a small amount of white foamy sputum, which occurs mostly after exertion. The coughing time is not fixed and is not related to body position. (2) Hemoptysis or hemoptysis is caused by the rupture of capillaries due to necrosis and ulceration of cancer tissue. The amount and duration of hemoptysis are related to the degree of damage to blood vessels in cancer tissues. It is mostly persistent, with blood in the sputum or small blood clots, and the blood is bright red or dark red, which is not easily controlled by general treatment. The blood volume of hemoptysis or bloody sputum is usually small. In a few cases, the cancer encroaches on large blood vessels and may cause large mouth hemoptysis. (3) Chest pain Chest pain mostly appears in the middle and late stages of lung cancer, but if the cancer tumor is located near the pleura, chest pain may appear earlier, which may be irregular hidden pain or dull pain. When the cancer tumor directly invades the pleura, there may be sharp chest pain, which is aggravated when coughing or breathing. (4) Fever Fever rarely occurs in the early stage of lung cancer, but when the cancer tissue is necrotic, it can cause low or moderate fever, and antibiotic treatment is ineffective. When the central type lung cancer near the lung door grows to obstruction or semi-obstruction in the bronchial lumen, it can cause obstructive pneumonia and generalized fever, and the body temperature is usually around 38℃. (5) Joint swelling and pain Pain is mainly in the large joints, mostly in the ankle joint, followed by the wrist joint, without wandering, not related to weather changes, local swelling can occur, X-ray pictures, except for occasional thickening of the periosteum, most of the other abnormalities. Some patients may have pestle-like finger (toe) performance. These symptoms are clinically referred to as pulmonary osteoarthropathy or ectopic growth hormone syndrome. Taking anti-rheumatic pain medication does not make the whole course of the disease better, and once the lesion in the lung is removed, the symptoms of arthralgia also disappear. (6) Skin changes A small number of people may show pruritic skin rash, dermatomyositis, herpes zoster, etc. in the early stage. (7) Endocrine system disorders A small number of patients can also see progressive muscle weakness, muscle atrophy, diabetes mellitus, swelling of lower limbs, enlarged male breasts, testicular atrophy, etc. About one-third of early stage lung cancer patients have no symptoms, and some other patients have slight early symptoms, but they are not taken seriously or misdiagnosed, thus delaying the disease. Therefore, to detect early lung cancer patients, it is also necessary to conduct large-scale population screening on a regular basis, especially for factories, mines and cities with high incidence rates, which should be conducted once a year. For patients over 40 years of age, (1) those with chest pain of unknown origin, hemoptysis and sputum that has been ineffective after treatment; (2) those with repeated inflammation in the same part of the lung that has been treated with active anti-inflammatory therapy with poor results; (3) those with tuberculosis that has been stabilized by treatment and then suddenly the lesion recurs and worsens, with inflammatory infiltration in a segment or lobe of the lung, local emphysema or pulmonary atelectasis, should be highly alert and undergo further examination.