New colorectal cancer (CRC) screening guidelines from the U.S. Preventive Services Task Force (USPSTF) urge annual screening for people ages 50 to 75 using high-sensitivity fecal occult blood testing, sigmoidoscopy every five years (with fecal occult testing between sigmoidoscopic exams), or colonoscopy every 10 years.

These new USPSTF guidelines update the 2002 version that only suggested screening for average risk adults age 50 and older and did not make any specific recommendations regarding the type of test or screening interval. The new guidelines encourage patients and clinicians to jointly choose the appropriate screening methods, although colonoscopy is considered to be the standard against which other screening tests are compared.

Because colonoscopy is an invasive procedure, it has a greater risk of complications than any other screening methods. Sigmoidoscopy is less invasive and carries little risk of complications, while fecal occult blood has virtually no risk. However, if these tests detect the presence of polyps, the patient will require a follow-up colonoscopy.

Colorectal cancer is the third most common cancer and the second leading cause of cancer death in the United States. In 2005, only about half of adults age 50 and older had been screened for the disease.

"Screening for colorectal cancer saves lives," said Task Force Chair Ned Calonge, M.D., chief medical officer for the Colorado Department of Public Health and Environment. "Current rates for colorectal cancer screening are much lower than other types of cancer screening. We hope patients and physicians will discuss the potential benefits and harms and choose an appropriate screening method for them."

USPSTF also newly recommends when to stop regular colorectal screening. The updated guidelines advise against screening patients older than 85 and recommend that those between the ages of 76 and 85 consider individual health status, results of prior screening, and life expectancy before submitting to the screening process.

These recommendations are for patients who are 50 to 75 years old and who have no other risk factors. Those individuals with a personal history of certain types of polyps or who have a family history of rare syndromes that increase a person's chances of getting colon cancer must be followed more closely and may require more frequent screening episodes.

Two newer procedures that have shown great promise are computed tomographic colonography (also known as CTC or “virtual colonoscopy”) and fecal DNA testing. However, the fecal DNA test has not been approved for marketing by the US Food and Drug Administration (FDA). While the Task Force did not find sufficient evidence to fully assess the benefit or harm that might be associated with these new procedures, the March guidelines from the American Cancer Society’s Multi-Society Task Force on Colorectal Cancer and the American College of Radiology both endorse their use. CT colonography is particularly useful for the detection of adenomatous polyps, while the stool DNA assay is useful in the early detection of colon cancer. (See the news article from May 7, 2008: New Colorectal Cancer Screening Guidelines Issued)

The Barium enema procedure has been used for many years but was not included in the updated recommendations because of its lower sensitivity and because it has not been used in screening trials. More recently, its use as a screening method for colorectal cancer has declined in the US.

As with any procedure, a certain level of risk may be present. Because colonoscopy and sigmoidoscopy are invasive procedures, there can be some risk of tearing of tissue or infections. However, the risk of not detecting colorectal cancer early on can have even greater impact on a patient’s health.

Sources

Zauber, Ann et al. Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement. Annals of Internal Medicine 2008; 149. Available online at http://www.annals.org/cgi/content/full/0000605-200811040-00243v1#FN. Accessed October 27, 2008.

Agency for Healthcare Research and Quality Press Release. Task Force Finds Several Methods Equally Effective for Colorectal Cancer Screening. Available online at http://www.ahrq.gov/news/press/pr2008/colcanscr.htm. Issued October 7, 2008. Accessed October 27, 2008.

Colorectal Cancer Coalition Press Release. USPSTF Updates Screening Guidelines. Available online at http://fightcolorectalcancer.org/research_news/2008/10/uspstf_updates_screening_guidelines. Issued October 9, 2008. Accessed October 27, 2008.