Complications in late stage of colon cancer are as follows: 1) intestinal obstruction, intestinal obstruction will cause intestinal bowel obstruction, which sometimes requires emergency surgery; 2) obstruction, and the most serious one is intestinal perforation, because sometimes some patients who are diagnosed late will have perforation after obstruction for a long time, which is a complication of obstruction; 3) intestinal bleeding, ulcerative masses and constrictive masses will cause bleeding; 4) systemic manifestations, if there is bone metastasis, it will cause great pain, and some people cannot sleep all night, which requires tertiary analgesic treatment for cancer; 5) in late stage, there can be malnutrition, which can appear in a state of cachexia, like wasting and bone thinness.