May 7th, 2010

Colorectal Cancer Screening with Flexible Sigmoidoscopy Reduces Incidence and Death


Among individuals between 55 and 64 years of age, one screening using flexible sigmoidoscopy can reduce risk of developing colorectal cancer and dying from the disease, according to a study published in The Lancet.

Colon cancer is the second leading cause of cancer death in the United States. If detected and treated early, colorectal cancer is highly curable. Screening for colorectal cancer is recommended starting at the age of 50 for individuals at average risk of developing the disease and earlier for those at higher risk. Several screening tests are available, including the fecal occult blood test (FOBT), sigmoidoscopy, double-contrast barium enema, and colonoscopy.

Flexible sigmoidoscopy involves the use of a lighted tube, which the physician uses to look inside the rectum and the lower part of the colon (sigmoid colon) for polyps or areas suspicious for cancer. The physician may perform a biopsy in order to collect samples of suspicious tissues or cells for closer examination. Sigmoidoscopy is an outpatient procedure that does not require sedative anesthesia or pain medication. There are no or few complications associated with this procedure.

To evaluate whether one screening with flexible sigmoidoscopy among patients 55 to 64 years of age could effectively reduce colorectal cancer incidence and mortality, researchers in the UK enrolled approximately 170,000 men and women in a multicenter study. Participants were either offered screening with sigmoidoscopy (intervention group) or were not (control group).

  • 71% of people assigned to the sigmoidoscopy group attended their sigmoidoscopy appointment and were screened.
  • Overall, people in the sigmoidoscopy group were 23% less likely to develop colorectal cancer and 31% less likely to die of the disease than people in the control group.
  • When people who didn’t show up for their sigmoidoscopy appointment were excluded, the benefit of sigmoidoscopy was even more apparent: Compared with people in the control group, people in the sigmoidoscopy group were 33% less likely to develop colorectal cancer and 43% less likely to die of the disease. The results of this subgroup analysis should be interpreted with caution, however. People who showed up for screening could differ in important ways from those who didn’t show up, and this could bias the results. The researchers attempted to account for this potential source of bias in their analysis.

The results of this study suggest that one colorectal cancer screening with flexible sigmoidoscopy between the ages of 55 and 64 may substantially reduce colorectal cancer incidence and mortality.

Reference: Atkin WS, Edwards R, Kralj-Hans I, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. The Lancet [early online publication]. April 28, 2010.


Tags: Uncategorized, UNM CC Features