Typical symptoms of lung cancer are cough, blood in sputum, chest pain, shortness of breath and other lung manifestations; however, according to statistics, about half of the patients suffering from lung cancer initially show symptoms outside the lungs, and they often appear before the lung symptoms, which invariably become the early signs of lung cancer. However, since these symptoms do not seem to be related to lung cancer, they are often misdiagnosed as other diseases. Therefore, we should be alert and pay attention to grasp these signals, which will be helpful for early diagnosis and early treatment. What are the main extra-pulmonary symptoms of lung cancer? 1. Bone and joint symptoms: such symptoms are more common. Because lung cancer cells can produce certain special endocrine hormones (heterogenous hormones), antigens and enzymes, these substances can operate on bone and joint parts, resulting in swelling and pain of bone and joint, often involving tibia, fibula, ulna, radius and other bones and joints, and the ends of fingers and toes are often expanded to pestle-like fingers. 2.Shoulder and back pain: Pulmonary peripheral type lung cancer often develops posteriorly, erodes the pleura and involves the ribs and chest wall tissues, thus causing shoulder and back pain. Such patients rarely have respiratory symptoms. 3. Hoarseness: lung cancer metastases compress the laryngeal nerve, which can cause hoarseness due to vocal cord veneer paralysis. Since metastases of lung cancer can appear in early stage and county metastases can sometimes grow faster than the primary ones, the clinical manifestations of metastases can appear before the primary ones. 4.Neurological symptoms: brain metastasis of lung cancer may show neurological symptoms such as headache, vomiting, sudden coma, aphasia and hemiparesis, which are often misdiagnosed as and thrombosis and brain tumor due to the lack of obvious lung symptoms. 5. Male breast enlargement: About 10%-20% of male lung cancer patients have breast enlargement, unilateral but mostly bilateral, and this symptom appears about one year earlier than pulmonary symptoms such as cough, blood in sputum, chest pain and shortness of breath. This is because certain lung cancer cells can secrete chorionic gonadotropin, a hormone that can cause hyperplasia of breast tissue and make the breast hypertrophy.