Symptoms of lung cancer mainly include symptoms caused by primary tumor, local invasion symptoms, distant metastasis symptoms and extrathoracic manifestations. 1. Symptoms and signs caused by primary tumor: cough in early stage, hemoptysis or blood in sputum, chest pain, fever in central lung cancer, emaciation in late stage. 2. Symptoms of local invasion: chest pain when invading pleura or chest wall, hoarseness caused by compressing the recurrent laryngeal nerve by invading mediastinal lymph nodes, dysphagia caused by invading esophagus, pleural effusion caused by involving the pleura, pericardial effusion caused by involving pericardium, edema of upper extremities and varicose veins of the chest wall by invading the mediastinum and compressing superior vena cava. 3. Symptoms of distant metastasis: central nervous system metastasis can lead to headache, nausea, vomiting, etc. Bone metastasis can lead to bone pain and pathologic fracture; liver metastasis can lead to pain in the liver area and jaundice. 4. Extrathoracic manifestations: there may be endocrine syndrome, manifesting as hyponatremia, centripetal obesity, hypercalcemia, etc.; it may also lead to skeletal connective tissue syndrome, manifesting as mortar and pestle finger, muscular weakness, etc. Lung cancer symptoms are related to tumor size, type and stage of development, etc. There are also some patients who are asymptomatic and only found during physical examination. Therefore, it is recommended that chest imaging should be performed regularly, and those who are suspected of having lung cancer should consult a doctor in time.