Most of the patients who come to the hospital for treatment are already in advanced stage, and various treatments seem to be powerless, so patients and their families have to suffer from both physical and mental blows. So, can lung cancer, which is still the most prevalent tumor, be detected at an early stage? Lung cancer often shows clinical symptoms only when the disease has progressed to an advanced stage. Therefore, only about 15% of lung cancer patients can be diagnosed early before the cancer cells spread to adjacent lymph nodes or other sites. Lung cancer patients with no metastasis in the lymph nodes have a 5-year survival rate of 50%. Unfortunately, many patients have cancer cells that have spread even before a definitive diagnosis is made with available tests. Many early stage lung cancers are diagnosed incidentally, that is, patients are found to have lung cancer only when they are examined due to other diseases. For example, patients with heart disease, pneumonia or other diseases of the lung that require imaging, bronchoscopy, or cytology of cancer are accidentally found to have early-stage lung cancer. If you have untreated cough, hemoptysis and vague chest pain, especially for people over 40 years old, the following symptoms should alert you to the possibility of lung cancer: 1. Sudden onset of irritating cough for more than 2 weeks in people over 40 years old, and treatment is ineffective. 2.Changes in the nature of cough in people with existing cough. 3.Patients with tuberculosis who have failed regular anti-TB treatment and have progressive enlargement of focal shadows, segmental pneumonia or pulmonary atelectasis and eccentric cavity detected by X-ray. 4, high-risk groups such as long-term smokers, long-term exposure to radioactive substances and those with a family history of tumor disease.