The clinical manifestation of lung cancer is closely related to the location, size, whether the cancer is compressed, invading adjacent organs and whether there is metastasis. Early stage lung cancer Early stage, especially peripheral type lung cancer, often has no symptoms and is mostly detected during chest X-ray examination. After the cancer grows in the larger bronchial tubes, irritating cough often appears, which is very easy to be mistaken for cold and flu. When the cancer continues to grow and affects the drainage and secondary lung infection, there can be purulent sputum and the volume of sputum increases than before. Another common symptom is bloody sputum, usually with blood spots, blood shreds or intermittent hemoptysis in small amounts; hemoptysis in large amounts is rare. Some patients with lung cancer may experience clinical symptoms such as chest tightness, croup, shortness of breath, fever and chest pain due to the large bronchial obstruction caused by the tumor to varying degrees. Advanced lung cancer can produce the following signs: 1. compression or invasion of septal nerve, causing ipsilateral septal muscle paralysis; 2. compression or invasion of recurrent laryngeal nerve, causing vocal cord paralysis and hoarseness, 3. compression of superior vena cava, causing angry veins in face, neck, upper limbs and upper chest, subcutaneous tissue edema and elevated venous pressure in upper limbs; 4. invasion of pleura, causing pleural effusion, often bloody; large amount of effusion, causing The cancer invades the mediastinum and compresses the esophagus, which can cause dysphagia; (6) lung cancer at the top of the upper lobe can invade the mediastinum and compress organs or tissues located in the upper thorax, such as the first rib, subclavian artery and vein, brachial plexus nerve, cervical sympathetic nerve, etc., producing severe chest and shoulder pain, venous anger in the upper limbs, edema, arm pain and upper limb The cervical sympathetic nerve syndrome, such as ipsilateral upper eyelid ptosis, pupil narrowing, eye entropion and facial anhidrosis, is produced. After lung cancer metastasizes bloodstream, different symptoms will occur according to the invaded organs. A few lung cancers present non-metastatic systemic symptoms due to endocrine substances produced by the cancer: e.g. osteoarthrosis syndrome (pestle and mortar fingers, osteoarthralgia, osteochondral hyperplasia, etc.), Cushing’s syndrome, myasthenia gravis, male breast enlargement, polymyalgia, etc. These symptoms may disappear after resection of lung cancer. Diagnosis Early diagnosis has an important exhaustive meaning. Only if the lesion is diagnosed and treated early at the early stage can we obtain better treatment effect. For this reason, cancer prevention and education should be widely carried out to discourage smoking and to establish and improve the lung cancer prevention and treatment network. For adults over 40 years old, regular chest X-ray screening should be conducted. If middle-aged people or above have cough that is not cured for a long time or have bloody sputum, they should be alert and make thorough examination; if a lump shadow is found in the lung on chest X-ray, the diagnosis of lung cancer should be considered first and it is appropriate to conduct detailed further examination; the diagnosis of lung cancer should not be given up easily or delayed, and if necessary, the chest should be dissected and probed. At present, 80% of lung cancer cases have lost the chance of surgical treatment when they are clearly diagnosed, therefore, how to improve the early diagnosis rate is a very urgent issue.