Evidence supports “backing off” from screening colonoscopies every five years for patients who had one or two nonadvanced adenomas removed during a prior colonoscopy, as reported at the World Congress of Gastroenterology at ACG 2017.
Findings were reported from more than 66,000 US veterans followed at any one of 13 Veterans Affairs medical centers for an average of more than seven years. The 10,220 patients who underwent a second screening colonoscopy after an index colonoscopy that led to removal of one or two nonadvanced adenomas had 0.16 percent colorectal cancer mortality, compared with 0.13 percent among 8,718 patients with a similar history who did not receive follow-up colonoscopy. The rate of colorectal cancer death was 0.12 percent among 47,629 control veterans who had no adenomas removed during their index colonoscopy.
The differences among the three subgroups were not statistically significant after adjustment for baseline differences in age, sex, race, number of comorbidities, and tobacco use, as said by a gastroenterologist and professor of medicine at Indiana University, Indianapolis.
In current US practice, many gastroenterologists perform follow-up colonoscopy about five years after removing one or two nonadvanced adenomas during a screening colonoscopy. Deferring follow-up colonoscopy in the absence of any clinical indication seems advisable, especially for older patients two or more comorbidities who had a high-quality index colonoscopy with good preparation and good colonic visibility.
No randomized trial results have documented the need for stepped up colonoscopies in patients with a history of one or two nonadvanced adenomas, and these new observational findings are consistent with prior observational reports.
These data need to be integrated with common sense. An extended interval before repeat surveillance seems particularly appropriate for patients with a higher risk for adverse effects from the colonoscopy preparation and for patients more likely to die from cancer.
Backing off on repeat colonoscopy “minimizes the harm from surveillance.” As patients get older they don’t tolerate the prep as well. It grows more onerous, and the return diminish.
The patients included in the review had their index colonoscopy performed during 2002-2209, when they averaged about 61 years old, and about 95 percent were men. Their average Charlson comorbidity index was about 1.3. The incidence of colorectal cancer during follow-up after the index colonoscopy was 0.18 percent in patients with one or two nonadvanced adenomas in their index examination and no follow-up colonoscopy, 0.71 percent in those with nonadvanced adenomas who had one or more subsequent colonoscopies, and 0.31 percent in the people with no adenomas removed during the index procedure.
The rates of all-cause death during follow-up of the three subgroups were notably different: 34 percent in those with nonadvanced adenomas and no repeat colonoscopy, and 13 percent in patients with nonadvanced adenomas and repeat colonoscopy, and 21 percent in those without nonadvanced adenomas. Some discounted the significance of comparing rates of all-cause mortality, stressing that the most relevant primary endpoint is colorectal cancer mortality.