RSS Feeds
Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation
Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.
Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians.
Who developed these guidelines?
The U.S. Preventive Services Task Force is a group of health experts that makes recommendations about preventive health care.
What is the problem and what is known about it so far?
Colorectal cancer (cancer of the colon [large intestine] or rectum) is a common cause of death from cancer in the United States. Screening detects abnormal growths in the colon (polyps) before they become cancer and detects cancer at an early, curable stage.
Common screening tests for colorectal cancer include fecal occult blood testing (FOBT), sigmoidoscopy, and colonoscopy. Fecal occult blood testing detects traces of blood in stool. A positive result on FOBT should lead to colonoscopy. Sigmoidoscopy involves looking into the rectum and lower colon through a flexible instrument with a camera on its tip. Colonoscopy uses a similar instrument to look at the entire colon. During colonoscopy, doctors can take samples of the colon for biopsy and remove polyps.
Newer screening tests for colorectal cancer include computed tomography, colonography (virtual colonoscopy), and stool tests that use DNA-based technology. Colonography takes about 10 minutes and does not require sedation, but patients must take laxatives before the test, on regular colonoscopy, and it involves exposure to radiation. Abnormal results as for virtual colonoscopy must be followed up with regular colonoscopy. The DNA-based stool test is more expensive than FOBT but might be more accurate.
How did the U.S. Preventive Services Task Force develop these recommendations?
The U.S. Preventive Services Task Force reviewed published studies to learn about the risks and benefits of various colorectal cancer screening tests and of screening patients at different ages. They also used computer models to help define the risks and benefits of different starting and stopping ages for screening based on the best evidence available.
What did the authors find?
Good-quality evidence shows that screening with FOBT, sigmoidoscopy, or colonoscopy reduces deaths from colorectal cancer for patients age 50 to 75 years. Evidence also shows that the relative benefit of colorectal cancer screening decreases after age 75 years because people become increasingly likely to die of another cause before they die of colorectal cancer. The USPSTF concluded that after age 85 years, the risks of screening outweigh the benefits.
What does the U.S. Preventive Services Task Force recommend that patients and doctors do?
Patients age 50 to 75 years should be screened for colorectal cancer with FOBT, sigmoidoscopy, or colonoscopy. Patients and doctors should discuss the advantages and disadvantages of the different tests when choosing which test to use.
Patients age 76 to 85 years should have screening only if they are likely to live for at least another 10 years. Patients older than 85 years should not have colorectal cancer screening. Patients who are considering virtual colonoscopy or DNA-based stool testing should understand that the definite role of these tests in colorectal cancer screening is not yet known.
What are the cautions related to these recommendations?
The recommendations apply only to patients who are at average risk for colorectal cancer and do not have symptoms of colorectal cancer. The recommendations may change as new studies become available.
Article and Author Information
-
The summary below is from the full reports titled Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement, Screening for Colorectal Cancer: A Targeted, Updated Systematic Review for the U.S. Preventive Services Task Force, and Evaluating Test Strategies for Colorectal Cancer Screening: A Decision Analysis for the U.S. Preventive Services Task Force. They are in the 4 November 2008 issue of Annals of Internal Medicine (volume 149, pages 627-637, pages 638-658, and pages 659-669). The first report was written by the U.S. Preventive Services Task Force; the second report was written by E.P. Whitlock, J.S. Lin, E. Liles, T.L. Beil, and R. Fu; and the third report was written by A.G. Zauber, I. Lansdorp-Vogelaar, A.B. Knudsen, J. Wilschut, M. van Ballegooijen, and K.M. Kuntz.
