The early diagnosis of cancer is mainly the awareness of physical examination, which helps to detect cancer at an early stage. For example, men with long-term smoking history should pay attention to lung cancer screening and have regular lung CT examinations, which can help to detect occupying lung lesions at an early stage. For occupying lesions in the lung, timely pathological puncture biopsy or direct surgical excision can determine whether it is cancer or not. Because small lesions at this time do not have lymph node metastasis or distant metastasis, they are early symptoms. For example, primary liver cancer is mainly diagnosed by ultrasound and regular examination of AFP in early stage. Especially for those who have a history of long-term alcohol consumption, chronic hepatitis B and fatty liver, abdominal ultrasound combined with AFP examination once every 6 months can detect early liver cancer. Early stage liver cancer refers to tumor less than 3cm, and tumor of 3cm can be cured by surgical removal.