Researchers attempted to quantify the effect surveillance colonoscopy had on colorectal cancer prevention in a study published in Clinical Gastroenterology and Hepatology.
Researchers followed patients in a prostate, lung, colorectal and ovarian cancer screening trial who used surveillance colonoscopy after a previous sigmoidoscopy returned positive findings. They documented CRC incidence rates.
Of the 15,935 patients in the colonoscopy cohort, 2,882 had advanced adenomas, 572 had three or more non-advanced adenomas, 4,496 had up to two non-advanced adenomas, and 7,985 had no anemones.
The advanced adenoma cohort underwent an average of 1.8 surveillance colonoscopies over a 10-year period, the three-or-more cohort underwent an average of 1.63 surveillance colonoscopies, and the up-to-two cohort underwent an average of 1.46 colonoscopies.
In the respective groups, there were 56, four and 33 confirmed cases of CRC.
Researchers believe surveillance colonoscopy during 10 years of follow-up prevented 30 percent of CRC cases; however, they noted their indirect estimation means the true effect of surveillance colonoscopy on CRC is unknown.