A detailed history and proper physical examination remain the most important steps in the evaluation of patients with lung cancer. Most patients with early-stage lung cancer have no obvious symptoms, so only about 5-15% of them are detected early. Most cases of lung cancer are detected because of symptoms that have spread and caused discomfort. The majority of lung cancer patients are male, with a male to female ratio of about 4-8:1, and most patients are over 50 years of age. Lung cancer often has no early symptoms, especially peripheral lung cancer, which is mostly discovered accidentally during chest X-ray examination. The clinical manifestations of lung cancer are closely related to the location, size, compression, invasion of adjacent organs and metastasis. Lung cancer symptoms may vary depending on the size and location of the tumor, but in general, it is a respiratory problem with the following signs and symptoms: 1. new or persistent cough (more than three weeks); 2. persistent chest pain, shoulder pain or back pain, usually worse when breathing deeply; 3. change in sputum color or blood in sputum or dark color; 4. croup/shortness of breath/difficulty in breathing/hoarseness. hoarseness, especially in new asthma; 5. Repeated infections such as pneumonia or bronchitis; 6. Fatigue, loss of appetite, weight loss. When lung cancer spreads to distant organs, it may cause headache, bone pain, joint pain, weakness or numbness in the arms or legs, dizziness, even abdominal pain, and unexplained fever (which may also occur in people with mild lung cancer). Lung cancer in the elderly Cough, sputum, hemoptysis and chest pain are the main symptoms of lung cancer, while most lung cancers in the elderly do not have general clinical manifestations and chest X-ray features. Since the early symptoms of lung cancer resemble respiratory tract inflammation, it is easy to be overlooked, especially during the epidemic of respiratory diseases in spring and fall, when lung cancer is more likely to be “hidden”. Symptoms of severe lung cancer may include headache, weakness, pain or fracture.