Carcinoembryonic antigen itself belongs to a kind of glycoprotein, and there are two possibilities for the value to fluctuate. Firstly, a certain value exists in the normal population, which will fluctuate by itself without intervention; secondly, it is a condition of unstable condition control during the treatment of tumor patients, which may need to adjust the treatment plan. 1. Normal people: Carcinoembryonic antigen fluctuates but the overall value is still within the normal range, which is only a physiological change and will not have too much influence on the physical condition, so there is no need for special intervention. 2. During tumor treatment: during the treatment period, if the carcinoembryonic antigen is high or low during the review, it is a manifestation of unstable tumor control, and the corresponding condition needs to be combined with the patient’s own physical condition and specific illness, and may need to adjust the treatment plan. If carcinoembryonic antigen is high or low, it is recommended to consult a doctor in time, combine with imaging examination and physical condition to make a comprehensive judgment, and carry out standardized treatment under the guidance of clinicians.