60 - Colorectal Polyp Location and Appearance in Cadavers

Poster Board Number: 60
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Odd poster #s – first hour
Even poster #s – second hour

Abstract Body : Introduction and Objective: Colorectal cancer (CRC) is a leading cause of mortality in the world. Even with advancements in preventative care, including colonoscopies and at-home screening tests, thousands die each year. Within recent years, research studies have focused on determining which factors have contributed to the continuing cases of CRC and its associated mortality. These studies have shown that failure to identify and remove colorectal polyps by colonoscopists has led to high incidents of CRC. The purpose of this study was to characterize the appearance and determine preferred locations of colorectal polyps relative to region, folds, and luminal circumference.
Materials and Methods: The colons and rectums of 33 embalmed cadavers (F=16; M=17; age=73.4yrs) were isolated. The specimens were incised longitudinally, opposite the position of vascular source or mesentery. Any remaining feces was removed and the specimen were bathed in light detergent to cleanse the lumen. Visible polyps were classified for appearance and measures of dimension and location were taken to the closest mm using graded rulers and calipers. The luminal location of each polyp was measured relative to the vascular source at 0˚/360˚ degrees and divided into quadrants with the vascular quadrant being between 315˚ and 45˚, anterior quadrant (45˚-135˚), non-vascular (135˚-225˚), and posterior (225˚-315˚). A Fisher’s Exact test was used to analyze the relationships between polyp appearance and the region of the colon or rectum it was found in, the location relative to the folds and haustra, and the luminal location.
Results: Fifteen of the 33 cadavers had at least one visible polyp to as many as 9, providing 48 identifiable polyps. Statistically significant associations were found between polyp appearance and region (P=.01), fold location (P<.001), and luminal location (P=.02). Seventeen polyps were raised in appearance, 13 flat, 11 pedunculated, 5 raised but not pedunculated, and 2 were elongated. Most of the polyps were found in the ascending colon (n=22) while the remainder were found in the transverse colon (n=10), rectum (n=9), descending colon (n=6), and cecum (n=1). Of the 9 cadavers with multiple polyps, 5 had polyps located in multiple regions of the colon. Relative to intestinal folds and haustra, most were found on the apex of a fold (n=26), with others found on the proximal surface of the fold (n=4), in the haustrum (n=4), on the distal surface of the fold (n=3), covering the entire fold (n=3) and 8 were indeterminable. Lastly, one-third of the polyps were found in the vascular quadrant of the lumen (n=16), with one-third in the non-vascular quadrant (n=16), 5 in the posterior, 2 anterior, and 9 indeterminable.
Conclusions: The goal of this study was to determine the preferred locations and appearance characteristics of colorectal polyps in cadaveric specimen. The more common characteristics were that polyps were raised, found either adjacent to or opposite the vasculature, on the apex of a fold, and found within multiple regions of the colon, but more so within the ascending colon.
Significance/Implications: Identification of colorectal polyps can be challenging. Cataloging the typical appearance and preferred location of these polyps may lead to more careful exploration of certain regions and surfaces yielding improved identification of polyps, their subsequent removal and reduced incidences of colorectal cancers.