Lesions of All Types Exist in Colon Polyps of All Sizes

Although large polyps are known to harbor more advanced neoplasia than small polyps, the extent of the relationship between size and type is not fully known. The study aim was to establish benchmarks for the prevalence of different histologic polyp types among varying size categories.

The Miraca Life Sciences Database is an electronic repository of histopathologic patient records from private practices throughout the United States. We extracted the records of 483,998 unique patients who underwent colonoscopy with polypectomy between January 2008 and December 2014. A total of 550,811 polyps were stratified by their endoscopic size measurement. Polyps of each size were further stratified as hyperplastic polyp (HP), tubular adenoma (TA), tubulovillous adenoma (TVA), sessile serrated adenoma/polyp, and adenocarcinoma.

Of all 550,811 polyps, 447,343 (81%) were 1-9 mm in size, and 103,517 (19%) were 10 mm or larger. A fraction of 18,591/550,811 polyps (3.4%) harbored histologic features of advanced adenoma, such as TVA, high-grade dysplasia, or cancer. Of these, 4,725/18,591 (25%) occurred in polyps 1-9 mm and 13,868/18,591 (75%) occurred in polyps 10 mm or larger. The fractions of advanced adenoma were 0.6% (0.5-0.6%) in 1-5 mm polyps and 2.1% (2.0-2.2%) in 6-9 mm polyps, as compared to 13.4% (13.2-13.6%) in polyps 10 mm or larger. The frequency of HP significantly decreased with increasing polyp size, whereas the frequency of TA remained largely unaffected by polyp size.

While advanced histopathology was found more frequently in colorectal polyps of larger than smaller size, one quarter of all advanced histopathology existed in polyps of <10 mm.