The recurrence of sigmoid colon cancer after surgery mainly includes local recurrence and distant metastasis. Local recurrence is often around the anastomosis, when symptoms such as difficulty in stool, blood in stool and abdominal pain will appear. Diagnosis can be made by colonoscopy and CT, which in turn will clarify whether there is metastasis. If the metastasis is distant, such as liver, lung or bone, the symptoms vary. In the early stage of liver and lung metastasis, most of them have no obvious symptoms. If there are more metastases, liver function will be abnormal, blood tests will reveal an increase in transaminases, and metastases in the lungs will increase. If it metastasizes to the bones, bone pain in the corresponding area will occur. If there are these symptoms, it suggests having distant metastasis. Therefore, colon cancer patients need to undergo regular postoperative review, including colonoscopy, CT of the chest and enhanced CT of the abdomen plus pelvis, which basically includes these recurrence sites and can be diagnosed in advance.