Risk of cancer in small and diminutive colorectal polyps

Abstract

The prevalence of cancer in small and diminutive polyps is relevant to “resect and discard” and CT colonography reporting recommendations. We evaluated a prospectively collected colonoscopy polyp database to identify polyps <10 mm and those with cancer or advanced histology (high-grade dysplasia or villous elements). Of 32,790 colonoscopies, 15,558 colonoscopies detected 42,630 polyps <10 mm in size. A total of 4790 lesions were excluded as they were not conventional adenomas or serrated class lesions. There were 23,524 conventional adenomas <10 mm of which 22,952 were tubular adenomas. There were 14,316 serrated class lesions of which 13,589 were hyperplastic polyps and the remainder were sessile serrated polyps. Of all conventional adenomas, 96 had high-grade dysplasia including 0.3% of adenomas ≤5 mm in size and 0.8% of adenomas 6–9 mm in size. Of all conventional adenomas, 2.1% of those ≤5 mm in size and 5.6% of those 6–9 mm in size were advanced. Among 36,107 polyps ≤5 mm in size and 6523 polyps 6–9 mm in size, there were no cancers. These results support the safety of resect and discard as well as current CT colonography reporting recommendations for small and diminutive polyps.