Colon And Rectum Cancer Symptoms.

Anyone with persistent symptoms that could be caused by a problem in the large bowel should see a doctor promptly. The most common symptom of a large bowel cancer is a change in bowel habits, usually either diarrhea, which is typical of a rectal cancer, or constipation, which is typical of a cancer in the left colon. If the tumor has extended beyond the wall of the colon and spread elsewhere in the body, symptoms might include enlargement of the liver, abdominal bloating, pain in the lower back, or bladder symptoms. Blood in the stools, as noted earlier, is another common early symptom, but this is not always apparent without a test for occult, or hidden, blood. Any recent change in bowel habits, or rectal bleeding or lower abdominal pain that does not subside promptly is a clear indication that medical attention should be sought.

Of course, the presence of these symptoms does not necessarily mean cancer. Hemorrhoids are a far more common cause of blood in the stool than cancer is. Typically, the bleeding from hemorrhoids appears as bright red blood found on the toilet tissue or present on the surface of the bowel movement or dripping into the toilet bowl. Patients who notice such bleeding should not panic; the blood loss is small, even though it might appear to be heavy. Hemorrhoids also cause anal discomfort and itching. Patients with these symptoms should be reassured that cancer probably is not involved; even so, a thorough examination of the rectum by a doctor is still necessary. This should include a digital examination, sigmoidoscopy, and possible examination with an anoscope, which is a small sigmoidoscope that enables a doctor to see the inside of the rectum.

Patients with potentially more serious problems will undergo a more extensive examination, which should include a full history of past health problems; general physical examination, including a digital rectal examination; test for occult blood; and sigmoidoscopy. In addition, either a barium enema examination with air contrast or colonoscopy is advisable. At the time of sigmoidoscopy or colonoscopy, biopsies should be taken from any suspicious area. Although a cancer of the large bowel may be readily apparent to the naked eye during sigmoidoscopy or colonoscopy, or be equally apparent from X rays taken during a barium enema, biopsies still should be obtained for microscopic confirmation of disease before treatment is started.

Symptoms affecting the lower gastrointestinal tract can be caused by a host of diseases other than cancer. One of the most common is diverticulosis, the formation of small outpouchings or pockets within the wall of the colon. About 20 percent of all people over the age of sixty will have one or more diverticulae. These out-pouchings sometimes become inflamed, leading to altered bowel habits, usually alternating bouts of diarrhea and constipation; lower abdominal pain, fever, and bleeding in the stool. Most people with diverticulosis, however, usually have no, or only minor, symptoms.
Narrowing of the bowel can result from scarring and thickening of the intestinal muscle, and when this occurs sometimes colonoscopy is necessary to rule out the possibility of cancer. Symptoms also may come from other intestinal inflammatory diseases, such as chronic ulcerative colitis or regional ileitis, also known as Crohn's disease. Since patients with these conditions do, in fact, suffer a higher rate of large bowel cancer, biopsies of the surface of the large bowel may be in order to identify any abnormal precancerous tissue changes (dysplasia) so that the disease can be diagnosed in its earliest stages and appropriate preventive measures undertaken. These may include surgery to remove all or part of the colon, thus eliminating the threat of future cancer.

About one out of twenty people with large bowel cancer may suddenly develop obstruction of the bowel or a perforation—that is, an opening in the large bowel. In cases of obstruction, a complete blockage of the bowel occurs, leading to pain and distension of the abdomen. The patient is unable to have a bowel movement or to expel gas. Surgery is the only treatment. In the case of perforation of the bowel, acute lower abdominal pain, which often spreads to the entire abdominal area, occurs. This condition is known as peritonitis and it calls for emergency surgery and treatment with antibiotics. Antibiotics are needed because the spilling of the bowel contents into the abdominal, or peritoneal, cavity can lead to life-threatening infection.