The Lifesaving Role of Colorectal Cancer Screening

Robert W. Summers, MD
University of Iowa Hospitals and Clinics

First Published: Summer 2000
Last Revised: March 2003
Peer Review Status: Internally Peer Reviewed

Clinical Guidelines for Colorectal Cancer Screening from the
American Gastroenterological Association (AGA)

Co-endorsed by: the American Society for Gastrointestinal Endoscopy (ASGE), the American Society of Colon and Rectal Surgeons (ASCRS), American College of Gastroenterology (ACG), and the Society of American Gastrointestinal Endoscopic Surgeons (SAGES)

• Screening for colorectal cancer and adenomatous polyps should be offered to all men and women without risk factors, beginning at age 50
• Physicians should recommend a diagnostic evaluation of the colon to follow up a positive screening test
• Follow-up surveillance must be continued after treatment of colorectal cancer or removal of adenomatous polyps or in the presence of underlying pre-malignant conditions, such as inflammatory bowel disease
• Screening should be accompanied by efforts to optimize the participation of patients and health care providers with respect to both screening tests and appropriate diagnostic follow-up

Putting the Guidelines into Practice

Most patients and many physicians often are surprised to learn that 6% of the population (that is, more than one in 20) will develop colorectal cancer (CRC) in their lifetime. This risk is doubled if a family member has had colonic polyps or CRC. Unfortunately, about half will die from CRC since they discover it at an advanced stage. This is true because the diagnostic test is usually done only in response to the development of symptoms, such as bleeding, pain, a change in bowel habits, or obstruction.

One of the most discouraging findings I see in my practice is CRC in people who waited to have a colonoscopy until they developed symptoms. The key to success in preventing and curing CRC is the adoption of the principle of screening. The practice of screening can prevent CRC through removal of polyps or promote cure through early detection and surgical resection. Thus, the need to educate our patients is critical in reducing CRC morbidity and saving lives.

Another major misconception is that CRC is a man's disease. Far fewer women undergo screening exams, even though the incidence in women and men is essentially equal. Unfortunately, embarrassment often plays a role in avoiding screening exams. A recent study confirmed this impression and again emphasized the important role of the physician in bringing up the subject, encouraging, and educating the patient. Publicity about CRC screening has had a great impact on attitudes, evidenced by the large upturn in requests for procedures following the discovery of President Reagan's CRC or the TV coverage of Katie Couric's colonoscopy.

Although screening of high-risk patients is very important, it must be recognized that the vast majority of colon cancers occur sporadically in people who have no identified risk factors (average-risk individuals). Screening must be initiated in patients without symptoms or risk factors at age 50. I also strongly agree with the importance of screening before age 50 in high-risk patients identified in the guidelines. Although CRC can rarely appear in people as early as their 20s and 30s, the greatest impact on colon cancer will be in the adoption of universal screening of people over 50. It is even more cost-effective than cervical cytology for ovarian cancer or mammography for breast cancer.

Since the publication of the screening guidelines in 1997, there is growing discussion of whether flexible sigmoidoscopy is an adequate screening exam, since only half of the colon is examined. At UI Hospitals and Clinics, we increasingly advocate complete examination of the colon (colonoscopy) every 10 years. Two recent articles in the New England Journal of Medicine confirm the limitations of flexible sigmoidoscopy for screening and are likely to be influential in changing patterns of practice.

We practice CRC screening to detect polyps or to find cancers at a very early stage so that they can be surgically removed before spreading occurs. It has been proven that the removal of polyps greatly improves the chance of preventing CRC. Even after polyps are removed, it is essential to perform these studies at regular intervals because new polyps are more likely to develop in people who have already had them.

See related Provider Textbooks about Cancer Center or Internal Medicine.

See related Provider Topics Cancer Center, Cancers, Colorectal Cancer, Digestive System, Internal Medicine, Preventing Disease and Staying Healthy or Wellness and Lifestyle.

See related Patient Textbooks about Cancer Center or Internal Medicine.

See related Patient Topics Cancer Center, Cancers, Colorectal Cancer, Digestive System, Internal Medicine, Preventing Disease and Staying Healthy or Wellness and Lifestyle.

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