digestive disorders
Colorectal Cancer
Symptoms of Colorectal Cancer
Colorectal cancer grows slowly and does not cause symptoms for a long time. Symptoms depend on the type, location, and extent of the cancer and on complications. Fatigue and weakness resulting from occult bleeding (bleeding not visible to the naked eye) may be the person’s only symptoms. A tumor in the left (descending) colon is likely to cause obstruction at an earlier stage, because the left colon has a smaller diameter and the stool is semisolid. The person may seek medical treatment because of crampy abdominal pain or severe abdominal pain and constipation. A tumor in the right (ascending) colon does not cause obstruction until later in the course of the cancer, because the ascending colon has a large diameter and the contents flowing through it are liquid. By the time the tumor is discovered, therefore, it may be larger than a tumor in the left. Most colon cancers bleed, usually slowly. The stool may be streaked or mixed with blood, but often the blood cannot be seen. The most common first symptom of rectal cancer is bleeding during a bowel movement. Whenever the rectum bleeds, even if the person is known to have hemorrhoids or diverticular disease, doctors must consider cancer as a possible diagnosis. Painful bowel movements and a feeling that the rectum has not been completely emptied are other symptoms of rectal cancer. Sitting may be painful, but otherwise the person usually feels no pain from the cancer itself unless it spreads to tissue outside the rectum. 