The symptoms of colon cancer in the middle and late stages are more obvious, mainly as follows: first, the earliest stage can have the symptoms of abdominal distension, discomfort and indigestion, and then there are changes in bowel habits, such as more frequent stools, alternating diarrhea or constipation, abdominal pain before stool, and later on mucus stool and mucus-purulent blood stool can appear. Second, toxic symptoms, mainly due to tumor ulceration, blood loss and toxin absorption, resulting in anemia, low fever, weakness, emaciation, swelling and other manifestations, among which anemia and emaciation are obvious. Thirdly, intestinal obstruction, mainly incomplete or complete low intestinal obstruction, manifested as abdominal distension, abdominal distension or colic, constipation, i.e. stool stopping to be discharged, physical examination can see abdominal bulging, abdomen with intestinal shape, local pressure pain, and hyperactive bowel sounds can be heard. Fourthly, abdominal masses, mainly the masses of infiltrated adhesions of abdominal tumors and peri-retinal tissues, are hard in texture, irregular in shape, and some can have certain mobility with the intestinal canal. In late stage, the tumor infiltrates and the mass can be fixed. Fifthly, signs of liver metastasis such as jaundice, ascites and swelling can appear, as well as signs of distant tumor spread such as cachexia, anterior rectal recess mass and supraclavicular lymph node enlargement.