Lung cancer is one of the malignant tumors with the fastest growing incidence and mortality rate, and the most threatening to human health and life. The prognosis of lung cancer is better in early detection and treatment, but poor in late stage, therefore, early detection and early treatment, so what are the signs of lung cancer? When lung cancer appears in early stage, there will be frequent prolonged cough, especially dry cough without sputum. The cough will become more and more severe as the disease worsens. Especially for smokers, it will be more serious, so please seek medical examination in time. Chest pain, many lung cancer patients will also feel obvious chest pain in the early stage, plus it will be more serious when coughing. White metabolic waste is one of the typical symptoms of lung cancer, because lung cancer lesions cause gallbladder obstruction, which in turn leads to white stool. Sudden weight loss, if you lose weight suddenly without diet or exercise, it is an abnormal phenomenon and is likely to be a sign of lung cancer. Oral changes, white spots on the oral mucosa and rapid expansion of the white spots accompanied by a burning sensation, especially in long-term smokers. Difficulty in breathing is one of the signs of lung cancer. Difficulty in breathing is mostly seen in the advanced stage of lung cancer because of extensive metastasis of mediastinal lymph nodes, which compress the trachea, rhomboid or main bronchus, and then shortness of breath or even suffocation. Lung cancer can cause joint pain in the extremities and wandering arthritis, which can cause pain like burning, and there are also symptoms such as impaired movement, edema and osteophytes. Lung cancer cells will secrete abnormal substances, such as hormones, antigens, enzymes or metabolites, during the process of growth, which will cause symptoms of gynecomastia, clinically known as tumor-associated syndrome. The pain that appears in the body will increase with the increase of age. But when pain appears inexplicably in a certain part of the body and lasts for more than a week, the cause should be identified as soon as possible, because pain without any reason may be a sign of cancer.