For most bowel cancers, the index of CA199 is normal. However, in the case of colon tumors, the index of CA199 is elevated or significantly elevated, indicating that the patient’s tumor is relatively advanced. It is possible that the tumor has invaded the plasma membrane or broken through the plasma membrane, and it is possible that the tumor has led to distant metastasis, such as the tumor will lead to liver metastasis, or lung metastasis, or the tumor has broken through the plasma membrane leading to pancreatic, or retroperitoneal nerve invasion. Generally, the tumor indicators of bowel cancer are more sensitive to carcinoembryonic antigen, that is, CEA may be elevated, but of course, there are some patients who have been diagnosed with bowel cancer and CEA is not elevated. If a patient has colon tumor and CA199 index is elevated, a more systematic examination should be conducted, including enhanced CT examination of the chest, abdomen and pelvis, and PETCT examination if necessary, focusing on whether the colon tumor has spread, and if it has spread, the effect of surgical treatment will not be good.