Cancer is mainly detected from two ways: First, health checkups. Some very early cancers are mainly found during health check-ups. Since most cancers do not have any symptoms in the early stage, or the symptoms are not typical and serious. Therefore, patients will ignore it and do not seek medical treatment, only to find out that the level of tumor markers in blood is elevated during physical examination, or that there are lumps in organs and tissues in chest X-ray or B-ultrasound. Then further examination and finally diagnosis is confirmed by pathological biopsy. Therefore, regular medical checkup is very important to detect early cancer. Secondly, go to the hospital when there are uncomfortable symptoms to confirm the diagnosis. Patients go to the hospital when they have uncomfortable symptoms, such as cough, hemoptysis, or lumps on the body surface, and then go to the hospital for further examination to find tumor. Most of these patients have already reached the middle and late stage when the tumor is diagnosed, and most of them have lost the chance of cure. In addition, there is another situation that malignant tumor is found when diagnosing or treating other diseases, for example, a patient with cold goes to the outpatient clinic and a lung mass is found in the chest X-ray, which is diagnosed as lung cancer after pathological biopsy, this situation may also happen.