Study Shows Flexible Sigmoidoscopy Effective for Colon Cancer Screening

A team of researchers led by doctors in Norway has found that screening with flexible sigmoidoscopy, one of the colon screening tests recommended by the American Cancer Society, reduced the rates of colon cancer diagnoses and deaths compared to no screening. Screening means testing for cancer while there are no signs or symptoms of the disease.

The researchers randomly assigned about 100,000 people in Norway between ages 50 and 64 to receive either a flexible sigmoidoscopy alone, a flexible sigmoidoscopy and fecal occult blood testing (FOBT), or no screening. During the time of the study, Norway did not have a national colon cancer screening program and people there generally did not receive screening.

After a follow-up period of about 11 years, the screening groups showed a reduced colon cancer incidence rate of 20% and a reduced colon cancer death rate of 27%. There was no significant difference between the two screening groups. The study was published August 12, 2014 in the Journal of the American Medical Association.

An easier colon preparation

Regular colon screening saves lives because it can often prevent cancer or find it early when it is easier to treat. This is because some colon or rectal polyps can be found and removed before they have the chance to turn into cancer. The American Cancer Society recommends colon cancer screening (there are several acceptable methods) for everyone starting at age 50, though some people may need to start at a younger age.

During screening with flexible sigmoidoscopy, the doctor looks at part of the colon and rectum with a sigmoidoscope – a flexible, lighted tube with a small video camera on the end. The doctor can find polyps and may remove them with a small instrument passed through the scope. A sigmoidoscope is basically a shorter, thinner version of a colonoscope, which a doctor uses to view the entire colon during a colonoscopy.

Like the preparation for colonoscopy, preparation for a sigmoidoscopy may also involve a special diet, laxatives, or enemas to clean the colon. However, it is generally an easier version to tolerate than the preparation for a colonoscopy. Most people do not need to be sedated for a sigmoidoscopy, and therefore, may drive themselves home from the procedure.

FOBT is a test mainly used to look for cancer, not precancerous polyps. People take these tests at home with a kit they receive from their doctor’s office, along with instructions. The tests do not require a bowel prep.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Effect of Flexible Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality: A Randomized Clinical Trial. Published August 12, 2014 in the Journal of the American Medical Association. First author Øyvind Holme, MD, Sorlandet Hospital Kristiansand, Kristiansand, Norway.

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