July 15, 2019
1 min read

Evidence supports closer CRC surveillance after some polypectomies

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Patients who undergo polypectomy during an initial colonoscopy screening are at higher risk for colorectal cancer, but only if the removed polyps fall into certain categories, according to study results.

Mingyang Song, MD, ScD, of the department of epidemiology at Harvard T.H. Chan School of Public Health, and colleagues wrote in Gastroenterology that society guidelines for intervals of colonoscopies vary greatly depending on the size or histology of the removed polyps, ranging from every 3 years to as long as every 10 years.

“Several guidelines have been proposed by different professional societies for the intervals of colonoscopy surveillance, depending on the most advanced findings on baseline colonoscopy,” they wrote. “However, these guidelines vary widely and are largely based on low or modest supporting evidence regarding CRC risk after polypectomy.”

Researchers analyzed data from three large cohorts comprising 122,899 individuals who underwent flexible sigmoidoscopy or colonoscopy: the Nurses’ Health Study 1 (1990-2012), Nurses’ Health Study 2 (1989-2013) or the Health Professionals Follow-up Study (1990-2012). They classified endoscopic findings into three groups: no polyp, conventional adenoma and serrated polyp. They further divided adenomas into nonadvanced ( 10 mm, high-grade dysplasia, or tubulovillous or villous histology) and advanced groups, and classified serrated polyps as large ( 10 mm) or small (< 10 mm).

During a median follow-up of 10 years, investigators identified 491 incident cases of CRC, including 51 in 6,161 patients with conventional adenomas, 24 among 5,918 patients with serrated polyps and 427 in 112,107 in individuals with no polyps found in their initial screening.

Compared with individuals with no polyps, patients with advanced adenoma were more likely to develop CRC (HR = 4.07; 95% CI, 2.89-5.72). The same was true for patients with large serrated polyps (HR = 3.35; 95% CI, 1.37-8.15).

However, researchers found no significant increase in risk for CRC among patients with nonadvanced adenoma or small serrated polyps.

“Our findings provide support for current guidelines which recommend repeat lower endoscopy within 3 years of a diagnosis of advanced adenomas and large [serrated polyps],” Song and colleagues wrote. “In contrast, nonadvanced adenomas or small [serrated polyps] may not require more intensive surveillance compared to individuals without polyps.” by Alex Young

Disclosures: Song reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.