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Colon cancer is a common disease, but screening can reduce your chances of developing it.
Colonoscopy is a commonly performed screening method for colon cancer. A tube,
light, and camera are inserted into the colon so that a doctor can see the inside of the colon. A
major advantage of colonoscopy is that doctors can detect polyps (growths that can turn
into cancer) in the colon and remove them at the same time (polypectomy). Also, if your
test shows no abnormalities and you do not have any risk factors, you will need a colonoscopy only
once every 10 years.
However, there are some disadvantages to colonoscopy. It requires taking time off work and
someone to accompany you. Colonoscopy requires sedation, and there is some risk that the colonoscopy
tube can tear the colon, requiring emergency repair.
Several physician and government organizations have endorsed alternatives to colonoscopy for
people older than 50 years with an average risk of colon cancer. These procedures need to be
repeated more often. If doctors find anything abnormal, the likelihood of which increases with age,
then a follow-up colonoscopy is needed.
“Virtual” colonoscopy is also called computed tomography
colonography or simply colonography. This screen uses x-rays to create pictures of the
interior of the colon. Like colonoscopy, colonography requires drinking a laxative to cleanse the
colon. Because a tube is inserted only into the rectum rather than the entire length of the colon,
usually no sedation is needed and there is minimal risk of perforation. However, colonography
involves radiation exposure.
Guidelines issued by a group of professional societies in 2008 state that data are sufficient to
show colonography’s effectiveness as a screening tool. However, the Centers for Medicare &
Medicaid Services and the US Preventive Services Task Force argue that there is not enough evidence
to assess colonography as a screen for colorectal cancer.
High-quality data show that flexible sigmoidoscopy can prevent colorectal cancer
incidence and mortality. The basic difference between colonoscopy and sigmoidoscopy is that
sigmoidoscopy looks at the lower colon and rectum. Therefore, sedation is usually not needed,
although some discomfort is possible. Instead of a laxative drink, an enema is given in
A fecal occult blood test, also called a fecal immunochemical test, is
low risk and done at home. A small amount of stool is placed on a card and sent to the doctor. Fecal
occult blood testing does not require diet restriction, bowel preparation, or time off of work, but
it is a less sensitive test so it should be done annually.
Evidence does not yet support any one of these screening tools over another, so in deciding which
screening option is best for you, consider your personal health situation and talk with your doctor.
Not all screening tests are covered by all insurance plans, so check to see if the test you prefer
National Cancer Institutewww.cancer.gov/cancertopics/factsheet/detection/colorectal-screening
American Cancer Societywww.cancer.org/cancer/colonandrectumcancer/moreinformation/colonandrectumcancerearlydetection/colorectal-cancer-early-detection-toc
American Gastroenterology Associationwww.gastrojournal.org/article/S0016-5085%2808%2900232-1/fulltext#sec2
US Preventive Services Task Forcewww.uspreventiveservicestaskforce.org/uspstf/uspscolo.htm
To find this and previous JAMA Patient Pages, go to the Patient Page link on
JAMA’s website at jama.com. Many are available in English and Spanish. A Patient Page on colon cancer was
published in the December 17, 2008, issue; one on colon cancer screening in the March 8, 2008,
issue; and one on colonoscopy in the March 16, 2011, issue.
Conflict of Interest Disclosures: The author has
completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none
Sources: National Cancer Institute, American Cancer Society, American Gastroenterology
Association, US Preventive Services Task Force
Sugerman DT. Options for Colorectal Cancer Screening. JAMA. 2013;310(6):658. doi:10.1001/jama.2013.57593