The simultaneous colonoscopic presence of serrated polyps and high-risk adenomas led to a fivefold increase in the odds of metachronous high-risk adenomas in a large population-based registry study reported in Gastroenterology (2017. doi: 10.1053/j.gastro.2017.09.011).
The data “support the recommendation that individuals with large and high-risk serrated lesions require closer surveillance,” said Joseph C. Anderson, MD, of White River Junction Department of Veterans Affairs Medical Center, Vt., with his associates. When discounting size and histology, the presence of serrated polyps alone was not associated with an increased risk for metachronous high-risk adenoma, they also reported. Although serrated polyps are important precursors of colorectal cancer, relevant longitudinal surveillance data are sparse. Therefore, the investigators studied 5,433 adults who underwent index and follow-up colonoscopies a median of 4.9 years apart and were tracked in the population-based New Hampshire Colonoscopy Registry. The cohort had a median age of 61 years and half of individuals were male.
SOURCE: AMERICAN GASTROENTEROLOGICAL ASSOCIATION
After adjusting for age, sex, smoking status, body mass index, and median interval between colonoscopies, individuals were at significantly increased risk of metachronous high-risk adenoma if their baseline colonoscopy showed high-risk adenoma and synchronous serrated polyps (odds ratio, 5.6; 95% confidence interval, 1.7-18.3), high-risk adenoma with synchronous sessile serrated adenomas (or polyps) or traditional serrated adenomas (OR, 16.0; 95% CI, 7.0-37.0), or high-risk adenoma alone (OR, 3.9; 95% CI, 2.8-5.4), vs. participants with no findings.
The researchers also found that the index presence of large (at least 1-cm) serrated polyps greatly increased the likelihood of finding large metachronous serrated polyps on subsequent colonoscopy (OR, 14.0; 95% CI, 5.0-40.9). “This has clinical relevance, since previous studies have demonstrated an increased risk for colorectal cancer in individuals with large serrated polyps,” the researchers wrote. “However, this increased risk may occur over a protracted time period of 10 years or more, and addressing variation in serrated polyp detection rates and completeness of resection may be more effective than a shorter surveillance interval at reducing risk in these individuals.”
The index presence of sessile serrated adenomas or polyps, or traditional serrated adenomas, also predicted the subsequent development of large serrated polyps (OR, 9.7; 95% CI, 3.6-25.9). The study did not examine polyp location or morphology (flat versus polypoid), but the association might be related to right-sided or flat lesions, which colonoscopists are more likely to miss or to incompletely excise than more defined polypoid lesions, the researchers commented. “Additional research is needed to further clarify the associations between index patient characteristics, polyp location, size, endoscopic appearance and histology, and the metachronous risk of advanced lesions and colorectal cancer in order to refine current surveillance recommendations for individuals undergoing colonoscopy,” they commented.
The study spanned January 2004 to June 2015, and awareness about the importance of serrated polyps rose during this period, they also noted.
The National Cancer Institute and the Norris Cotton Cancer Center provided funding. The researchers reported having no conflicts of interest.
