1.Gastrointestinal disorders such as loss of appetite, abdominal discomfort, fullness, constipation, diarrhea, or alternating diarrhea and constipation. 2.Symptoms of intestinal obstruction are generally the symptoms of late stage colorectal cancer, mostly manifested as low-level incomplete intestinal obstruction, mainly including abdominal pain, constipation, abdominal distension, vomiting, hyperactive intestinal peristalsis, and sometimes intestinal type can be seen. The symptoms are aggravated when the obstruction is complete. Blood in stool is the main symptom of colon cancer. Sometimes it shows as stubborn constipation and thin stool shape, which is caused by narrowing of intestinal lumen caused by distal colon cancer. It can also be manifested as diarrhea, paste-like stool, etc. 4. Abdominal mass is mostly seen in the right abdomen, which is one of the manifestations of ascending colon cancer and indicates that it is near the advanced stage. Most of them are cancer itself, but they can also be caused by intra-abdominal metastasis or inflammatory infiltration of tumor. 5.Systemic symptoms may include anemia, low fever, progressive emaciation, jaundice, ascites, cachexia, etc. to different degrees. 6, other symptoms of co-infection may cause chills and fever; perforation may cause diffuse or restricted peritonitis; invasion of the urinary system may cause symptoms related to the urinary system. In late stage, liver enlargement, jaundice, ascites, enlarged left supraclavicular lymph nodes and other symptoms specific to metastasis from other organs may appear. Various complications may also occur in advanced colon/rectal cancer, including intestinal obstruction, intestinal bleeding or perforation, septic peritonitis, peri-colonic abscess, and rectal bladder fistula.