Joseph C. Anderson
ORLANDO — Individuals in whom colonoscopy revealed both serrated colon polyps and high-risk adenomas showed a significantly higher risk for developing future high-risk adenomas, and may therefore have an increased risk for colorectal cancer than those with high-risk adenomas alone, according to research presented at the World Congress of Gastroenterology at ACG 2017.
These findings, which researchers also recently published in detail in Gastroenterology, suggest that patients with both serrated polyps (SPs) and high-risk adenomas (HRAs) may benefit from closer surveillance.
“We demonstrated that SPs alone do not predict conventional HRAs,” Joseph C. Anderson, MD, MHCDS, of White River Junction Veterans Affairs Medical Center and Dartmouth College, said during his presentation. “We also found that [SPs] predict future large SPs, so large SPs rather than conventional [HRAs] may be a better surveillance outcome in patients with index SPs to monitor success. ... Finally, we had a novel finding of showing there is an increased risk of HRA in patients with HRA and [sessile serrated polyps (SSPs)] or [traditional serrated adenomas (TSAs)].”
Because only limited data inform surveillance guidelines for patients with SPs detected on index colonoscopy, Anderson and colleagues evaluated population-based data from the New Hampshire Colonoscopy Registry (NHCR) to determine the risk for metachronous lesions in patients with clinically significant SPs, including large SPs exceeding 1 cm, SSPs or TSAs.
They evaluated data on 4,616 individuals (median age, 59 years; 47.5% men) who underwent two colonoscopies at 28 endoscopy facilities (median time to surveillance, 4.9 years). The absolute risk for metachronous HRA was 6.3%, and absolute risk for metachronous large SP exceeding 1 cm was 1.2%.
Compared with patients in a reference group with normal exams, patients with HRA and synchronous SPs (OR = 5.61; 95% CI, 1.72-18.28), those with HRAs and synchronous SSPs or TSAs (OR = 16.04; 95% CI, 6.95-37) and those with HRAs alone (OR = 3.86; 95% CI, 2.77-5.39) on index colonoscopy showed an increased risk for metachronous HRAs. Further, those with only large SPs (OR = 14.34; 95% CI, 5.03-40.86) or SSPs or TSAs (OR = 9.7; 95% CI, 3.63-25.92) at index colonoscopy showed an increased risk for large metachronous SPs.
“We have identified a subgroup of individuals with both high-risk adenomas and serrated polyps who may need more intense surveillance such as increased frequency of colonoscopies,” Anderson said in a press release. “We also observed that having serrated polyps on index exam is associated with an increased risk for future serrated polyps but not high-risk adenomas. Examining rates of serrated polyps rather than high-risk adenomas on follow-up colonoscopy may be the best way to monitor the success of surveillance in people with serrated polyps.”
One of the strengths of this study is the large size, thoroughness and longitudinal nature of the NHCR registry, which has collected comprehensive data on more than 150,000 colonoscopies across New Hampshire since 2004, according to the press release.
“We follow patients at each successive colonoscopy and can examine the risk that patients can have for future polyps based on an index exam,” Anderson said in the press release. “The NHCR provided data for a large group of individuals who had both an index and follow-up colonoscopy allowing us to address the important clinical question of risk for people with serrated polyps.”
Anderson and colleagues plan to further study risk factors and genetic mutations that can help identify individuals at risk for both serrated polyps and high-risk adenomas, who may therefore be at an increased risk for colorectal cancer, according to the press release.
A poster being presented at the meeting showed “that smoking is a particularly high-risk factor for both these groups,” he noted during his presentation. – by Adam Leitenberger
Anderson JC, et al. Abstract 1. Presented at: World Congress of Gastroenterology at American College of Gastroenterology Annual Scientific Meeting; Oct. 13-18, 2017; Orlando, FL.
Anderson JC, et al. Gastroenterol. 2017;doi:10.1053/j.gastro.2017.09.011.
Disclosures: The researchers report no relevant financial disclosures.
Editor's note: This article was updated on October 30 with clarifications from the study author.