Early stage lung cancer, especially peripheral 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. Another common symptom is bloody sputum, usually with blood spots, blood shreds or intermittent small amount of hemoptysis in the sputum; large amount of hemoptysis is rare. Further growth of tumor may cause different degrees of obstruction of larger bronchi, which may lead to clinical symptoms such as chest tightness, croup, shortness of breath, fever and chest pain. When advanced lung cancer presses and invades adjacent organs and tissues or distant metastasis occurs, it can produce the following signs: 1.pressing or invading septal nerve: causing ipsilateral septal muscle paralysis; 2.pressing or invading recurrent laryngeal nerve: causing vocal cord paralysis and hoarseness, 3.pressing superior vena cava: causing angry varices in face, neck, upper limbs and upper chest, subcutaneous tissue edema and elevated venous pressure in upper limbs; 4.invading pleura: causing Pleural effusion, often bloody; large amount of effusion can cause shortness of breath, and sometimes the cancer invades the pleura and chest wall, which can cause continuous severe chest pain; 5.Invasion of mediastinum and compression of esophagus: it can cause difficulty in swallowing; 6.Lung cancer in the top of upper lobe: also called Pancoast’s tumor, which can invade the mediastinum and compress the organs or tissues located in the upper thoracic opening After lung cancer metastasizes bloodstream, different symptoms will be produced according to the invaded organs. In a few cases of lung cancer, due to the endocrine substances produced by the cancer (paraneoplastic syndrome), non-metastatic systemic symptoms are presented clinically: such as osteoarthrosis syndrome (pestle and mortar fingers, osteoarthralgia, periosteal hyperplasia, etc.), Cushing’s syndrome, myasthenia gravis, male breast enlargement, and polymyalgia. These symptoms may disappear after lung cancer treatment.