Left side colon cancer pain is usually on the left side of the patient’s abdomen. Left side colon cancer is also known as descending colon as well as sigmoid colon, when the tumor appears, if the tumor is earlier may patients have no pain, when the tumor continues to develop, continues to progress, and the tumor enlarges, patients will have left side abdominal pain, and may also have left lower abdominal pain. If the tumor invades the peritoneum, the patient may have pain in the lower back, of course, if the tumor leads to the narrowing of the patient’s intestinal lumen and the formation of obstruction, the patient will have dilatation of the intestinal tube above the tumor, and may have pain and distension in the upper abdomen, or may have distension and pain around the navel, and so on. When the tumor appears in the left side colon of the patient, generally after clear diagnosis, surgical resection can be performed as far as possible with surgical resection as the main, but if it can not be surgically resected, the method of conversion therapy should be used, and if there is intestinal obstruction, emergency surgery should be performed to solve the problem of intestinal obstruction of the patient if necessary.