Colorectal cancer is the third most common cancer diagnosed in men and women in the USA. It is also the third leading cause of cancer death. This is a disease which can be prevented by a high fiber/ low fat diet, regular exercise and screening tests which identify pre-malignant polyps for removal. Screening tests are recommended after the age of 50. Individuals with a personal history of inflammatory bowel disease or first- or second-degree relatives with colorectal cancer should consult their physicians about starting the screening process at a younger age. The overall incidence and mortality of colorectal cancer has been decreasing with the exception of African-American men who in the majority of cases are diagnosed at a more advanced stage of the disease.
The primary treatment for colorectal cancer is surgery. Both radiation and chemotherapy are considered supplemental treatments that in selected cases improve local tumor control and/or survival. The earlier the disease is detected the better the chances for tumor control and survival. The best outcomes occur when the cancer has not spread through the muscle layer of the intestine or into the lymph nodes in the pelvis. Spread of disease to distant organs such as the lung and liver are typically associated with a 5-year survival of less than a 10%. Radiation therapy plays a role primarily in regions of the large bowel that are immobile such as the rectum. An area of special interest is the region of the low rectum near the anal sphincter that is critical for fecal continence. If the tumor is too close to the sphincter, the patient must have a colostomy. In selected cases pre-operative radiation and chemotherapy can shrink the cancer and allow the surgeon to preserve sphincter function. Following therapy the patient should continue to receive regular follow-up and in some cases a blood test known as CEA can be used to indicate tumor recurrence.