Carcinoembryonic antigen is a marker for many tumors and is more broad-spectrum so less specific. Carcinoembryonic antigen 7.5ng/ml is 2.5ng/ml higher than the reference value, and it should not be ignored. It should be further investigated for cancer. Because it is not very specific, it is more difficult to check all parts of the body, so see where the patient is uncomfortable. If there is discomfort, start by troubleshooting where there is discomfort. If some patients have mild elevation and are not uncomfortable, there is now a more advanced test called whole body PET-CT. if we do whole body PET-CT, if there is a tumor somewhere in the body, it will be visualized accordingly. If the tumor is too early, i.e. too small a mass, it may not necessarily be visualized. However, relatively obvious tumors can be ruled out. If the PET-CT still does not find the lesion, it is recommended to review the indicators regularly to see if there are any dynamic changes in the development of the PET-CT is very expensive, so if there is no problem with the ordinary body examination, it will be recommended to observe dynamically. For patients who smoke, it is better to quit smoking and review the indicator after 1 month to see if it has decreased. This is because in some patients, even if no cancer is detected, the level of this indicator may be high, but the level of increase is small. If you quit smoking, it may decrease. Therefore, there is still a relationship with smoking, and it is recommended that patients who smoke quit.