CA: A Cancer Journal for Clinicians, Vol 9, 29-33, Copyright
© 1959 by American Cancer Society
CANCER CLINIC
Carcinoma of the Large Bowel and Rectum
Dr. Parsons: There are significant differences anatomically, physiologically, pathologically and clinically in cancers of the right colon, the left colon and the rectum. The right colon is supplied by the superior mesenteric vessels, the left colon and rectum by the inferior mesenteric vessels. Cancer of the right colon is generally a flat, ulcerative lesion, whereas cancer of the sigmoid typically is a constricting "napkin-ring" type of lesion.
Clinically, cancer of the right colon is characterized by anemia, by loss of appetite and weight and by general weakness. The presence of these symptoms in any patient more than 40 years of age should excite the suspicion of cancer of the right colon and this should be the presumptive diagnosis until proved otherwise. It is tragic that these patients are often thought to have simple anemia and over a period of weeks or months are given various preparations, such as iron, vitamins, etc. The diagnosis can almost always be established positively by the roentgenologist.
Cancer of the left colon is characterized by a change in bowel habits, the patient becoming progressively more constipated. The stools contain blood. As the site of the lesion approaches the rectum, there is bright red blood. There is generally no great anemia. As the obstruction becomes more acute there are episodes of cramping pain.
Cancer of the rectum is characterized by tenesmus and by bright red blood in or on the stools. Usually the tumor can be felt by the examining finger. It can always be seen through the proctoscope or sigmoidoscope and can be biopsied.
Cancers of the large bowel and rectum offer probably the best prognosis of all major cancers. Failure to make a digital examination of the rectum in any routine examination is inexcusable.
