Studies Confirm Effectiveness of Colorectal Cancer Screening

Colorectal cancer (CRC) is often preventable, making screening for the disease essential. Recent studies show that two common screening practices are both effective.

A study published in The New England Journal of Medicine examined the effects of colonoscopy and sigmoidoscopy over 22 years of followup. Colonoscopy was associated with a two-thirds reduction in cancer risk, compared with those who did not get screened—a finding that supports existing guidelines of 10-year screening intervals for people with average risk. A separate study, published in the same journal, examined fecal occult blood testing (FOBT) during a 30-year period and found annual screening reduced the risk of dying from CRC by about a third, compared with individuals who were not screened using this method. Even patients taking the test once every two years lowered the risk of dying from CRC by 22 percent, compared with those not screened.

The results of these studies show that each method is effective but do not prove that one method is better than the other—that would require a head-to-head study. Two large randomized studies, one in the U.S. and another in Spain, are underway to compare CRC screening techniques.

While colonoscopy screening is more well-known, FOBT is less invasive and, initially, less costly, requiring stool samples to check for blood. An FOBT that reveals blood will need a colonoscopy follow-up to confirm and remove potential pre-cancerous polyps.