The five-year survival rate of lung cancer is directly related to whether it is detected early or not. The five-year survival rate of stage I lung cancer is 45%-50%, while by stage IV, the five-year survival rate drops to 1%. Unfortunately, however, more than half of lung cancer patients are already stage IV lung cancer by the time they are diagnosed. The trouble with early lung cancer screening is that there are no targeted biochemical indicators for lung cancer, while physical examination chest X-ray is not particularly effective in detecting early lung cancer. This means that early screening needs to be based on the judgment of clinical symptoms by doctors at all levels, and not only specialists, but also community doctors and family doctors in charge of general practice should pay attention to it. What are the early clinical symptoms of lung cancer? What should doctors pay attention to when receiving consultations? 1. Chronic cough Many patients have chronic cough symptoms, but this symptom is often easily ignored by doctors and patients or categorized as other causes. Especially with the poor air quality in China, cough symptoms are not too common and can easily be missed. If a patient’s cough persists for more than two or three weeks, it must be taken seriously. In addition to the need for differential diagnosis with respiratory allergies and respiratory infections, patients with asthma, chronic obstructive pulmonary disease, allergies or gastroesophageal reflux who have cough symptoms due to their primary disease need to be carefully identified during diagnosis. Blood clotting is also a common symptom of lung cancer, but it is not easily detected by the patients themselves and needs the attention of doctors. 2. Shortness of breath during action As another early symptom of lung cancer, this symptom is easily thought to be caused by old age, poor physical condition or obesity. If patients feel shortness of breath during daily activities without cardiovascular diseases, they need to pay attention to the screening of lung cancer. 3. Shoulder, back, chest and arm pain Lung tumors may compress nerves and cause pain in the patient’s shoulder, chest, back or arm – this symptom may even precede coughing and shortness of breath. If painful symptoms occur in these areas without primary injury, especially painful symptoms that worsen with coughing and breathing, close attention is needed. Up to 50% of lung cancer patients have chest or shoulder pain conditions at the time of diagnosis. 4. Recurrent infections (bronchitis and pneumonia) It is not uncommon for patients with recurrent pneumonia or bronchitis to be diagnosed with lung cancer clinically. If the tumor is close to the airway, it can cause obstruction making the patient more prone to lung infections. Long-term smoking or COPD can also cause lung infections and bronchitis, but these are also high risk factors for lung cancer. 5. Abnormal symptoms or decreased physical fitness Sometimes even seemingly unrelated symptoms are associated with lung cancer, especially in patients who smoke. For example, 1.7% of patients with non-small cell lung cancer experience knee pain in the early stages. In addition a combination of symptoms such as fatigue, loss of appetite, unexplained weight loss and even the onset of depression may indicate lung cancer. Imaging Unfortunately, imaging is not very effective in the early detection of lung cancer. However, recent studies have shown that CT screening can reduce mortality by 20% for certain patients, limited to those aged 55-74 years who smoke more than 30 packs per year. As well, for patients with a history of radon exposure and genetic susceptibility factors, CT scan also has screening significance. Currently, the number of lung cancer patients in China is in the growth phase for various reasons. Early screening is significant for the survival rate of patients, and attention to early clinical symptoms can save patients’ lives.