The breath-hold test has a certain correlation with human lung function, but breath-holding for 30 seconds cannot detect lung cancer. Clinical symptoms of lung cancer are usually manifested as cough, hemoptysis, shortness of breath, chest pain, fever and difficulty in swallowing, but the specific symptoms are related to factors such as tumor size, development stage, location and tumor type. Early stage may also show no obvious symptoms and can only be detected during routine physical examination and chest imaging. It is not recommended to identify lung cancer by any self-test such as breath-holding. If lung cancer is suspected, lung cancer can be detected by imaging tests such as chest X-ray, chest CT scan or PET-CT. If a patient has been diagnosed with lung cancer, he or she should choose the appropriate treatment according to the clinical stage and his or her own condition. If the patient is in the early stage of lung cancer, surgical treatment mainly resection can be performed to help reduce the possibility of metastasis and recurrence of tumor. If the patient is in the advanced stage of lung cancer or has lung cancer recurrence, drug therapy, mainly including chemotherapy and targeted therapy, can be carried out to help improve the patient’s survival quality and prolong the survival period. If one’s condition is not suitable for surgery, radiation therapy, supplemented by chemotherapy, can help to control tumor development to a certain extent. If one loses the indication for surgery and has entered the advanced stage of lung cancer and chemotherapy is ineffective, interventional treatment such as bronchial artery infusion chemotherapy can be performed, which helps to reduce pain.