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 lung cancer patients start with symptoms that are manifested outside the lungs and often appear before lung symptoms, which invariably become early signs of lung cancer. Pay attention to these signals, which will be helpful for early diagnosis and treatment. 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 enlarged to pestle-like fingers. 2.Shoulder and back pain: 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 compressing the laryngeal nerve can produce vocal cord paralysis and cause hoarseness. Since metastases of lung cancer can appear at an early stage, and the 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 thrombosis and brain tumor because of 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. In addition, some patients should pay enough attention to the following symptoms and go to the hospital to exclude lung cancer: 1. 5.Sudden progressive shortness of breath, chest tightness, and pleural effusion on chest X-ray without chills and fever; 6.Chest X-ray shows “inflammation of the lungs”, which cannot be completely controlled by treatment, and the symptoms recur or worsen; 7.Unexplained persistent pain in joints and muscles, numbness and burning pain in the skin, and fever, but 8.People who have a long history of smoking, a family history of cancer, or a high chance of exposure to carcinogenic substances such as asbestos, asphalt, arsenic, chromium, coal tar, etc. in their daily work, and who have respiratory symptoms.