A recent study uncovered adenoma detection rates significantly higher than those set in national guidelines in a recent study, suggesting that these benchmarks may be too low.

As potentially precancerous polyps, adenomas are important growths to detect and remove during screening colonoscopy. Adenoma detection rate (ADR) refers to the percentage of screened patients in whom at least one adenoma is found.

Current guidelines suggest screening ADRs of 15% for women at average risk (no symptoms of colorectal cancer and no family history of the disease) and 25% for men at average risk, noted Susan G. Coe, MD, and Michael B. Wallace, MD, MPH, in their report for Gastrointestinal Endoscopy. The investigators, both from the Department of Gastroenterology at the Mayo Clinic in Jacksonville, Florida, sought to determine average-risk screening ADRs and the prevalence of adenomas by location, size, shape, and degree of dysplasia in both men and women.

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After prospectively collecting data on a total of 864 average-risk patients undergoing screening colonoscopy, Coe and Wallace found that the overall average-risk screening ADR was 33.7% for both sexes combined. The ADR was 25% for women and 41% for men—significantly higher than the benchmarks advocated in national guidelines. 

“Our study suggests that national benchmarks may be too low given our increasing ability to find polyps using the high-definition colonoscopy tools that a majority of physicians use today,” commented Wallace, chief of Mayo Clinic’s gastroenterology and hepatology division, in a statement issued by the facility. “We want to be able to detect all polyps that may turn cancerous, and our study shows that these polyps may be more prevalent than had been recognized at the time national standards were drafted.”

In their study, which is part of the Endoscopic Quality Improvement Program (EQUIP) clinical trial, Coe and Wallace also found a higher rate of advanced polyps (growths larger than 1 cm or with more advanced precancerous pathology) in both men and women. Whereas studies using older, lower-definition colonoscopy screening technology had put detection rates of advanced polyps at approximately 5%, Coe and Wallace found that 8.7% of the women and 15.3% of the men studied harbored such growths.

The researchers suggested that high ADRs may lead to more effective colonoscopy.