There is no so-called precursor of lung cancer in men. Early stage of lung cancer may present symptoms such as cough, blood in sputum and chest pain. Lung cancer is a malignant tumor originated from bronchial mucosa or glands in the lungs. Some patients may have irritating dry cough or a small amount of sputum in the early stage, and the cough is often recurring and metallic sounding. Treatment with antibiotics has no effect. Or sputum with blood, a small number of patients may manifest hemoptysis. Chest pain as the first symptom accounts for about 25%, the tumor invades the chest wall or nerves, causing irregular vague pain or dull pain in the chest. Part of the cancer due to tumor obstruction caused by pneumonia or tumor necrosis tissue absorption, and fever manifestation, mostly repeated fever, with fever-reducing drugs can only temporarily relieve the symptoms of fever. If male patients have these symptoms, they should consult the doctor in time. As soon as possible to clarify the diagnosis, the doctor according to the specific condition to develop individualized diagnosis and treatment plan. Avoid delays.