Metachronous advanced neoplasia linked to diminutive polyp number, not histology

When to perform surveillance colonoscopy in patients previously diagnosed with colorectal neoplasms is one of the most significant questions facing experts creating guidelines for colorectal cancer (CRC) screening. This study by Vleugels et al. provides important information that should better inform this issue.

The authors pooled data from 12 different study cohorts of patients undergoing colonoscopy in either the United States or Europe. The cohorts included patients who underwent colonoscopy to follow up a positive fecal immunochemical test (FIT) or as a primary test for screening, surveillance, or symptom management. The authors found that diminutive adenomas (1-5 mm) rarely contained advanced histology (CRC, high-grade dysplasia, or more than 25% villous features) and that these lesions seldom defined patients regarding risk for metachronous neoplasms. They also found that high-risk patients defined by 1-2 diminutive adenomas with advanced histology were no more likely to develop metachronous advanced neoplasia (adenoma containing advanced histology, at least three diminutive or small nonadvanced adenomas, or an adenoma or sessile serrated lesion at least 10 mm) than were patients defined as low risk by their initial adenoma histology. Interestingly, multiplicity (more than three) of diminutive or small adenomas regardless of histology did predict a significantly increased risk of metachronous advanced neoplasia. These data support a resect-and-discard strategy (not sending the resected polyp to pathology) for diminutive polyps and polyp surveillance guidelines that employ less frequent colonoscopy to follow patients whose most significant finding at initial colonoscopy is a diminutive adenoma.

Future studies should examine the risk for metachronous neoplasms posed by diminutive adenoma within the milieu of other patient characteristics informing colorectal cancer risk.

Reid M. Ness, MD, MPH, AGAF, is an associate professor of medicine in the division compliance and a quality expert in the division of gastroenterology, hepatology, and nutrition in the department of medicine at Vanderbilt University Medical Center, Nashville, Tenn. He has no financial conflicts to disclose.