Advanced Colonic Adenomas and Colorectal Cancer Share Similar Dynamic Distribution Patterns

Abstract

Purpose: Due to the greater colorectal cancer (CRC) risks associated with advanced adenomas (AA), it is recommended that patients with AA undergo more frequent endoscopic surveillance. The purpose of this study was to explore the dynamic distribution patterns of AA in a large group of US patients. Methods: This retrospective study was conducted at Caris Life Sciences, a national specialized gastrointestinal (GI) pathology laboratory that receives specimens from ambulatory endoscopy centers across the U.S. Electronic data from the Caris database were analyzed, including patients' demographics, clinical information, endoscopic findings, biopsy sites, and histopathologic findings. We studied all patients with a diagnosis of adenomatous polyp (AP), including: tubular adenoma (TA), tubulovillous adenoma (TVA), and villous adenoma (VA), with or without high-grade dysplasia (HGD), diagnosed by a single Caris GI pathologist between 01/01/09 and 12/31/09. AA was defined as either: polyp size > 10mm, villous component > 25%, or HGD. The size of polyp was based on the endoscopic description or gross specimen measurement. Serrated polyps were excluded from this study. Results: Among 1,341 patients (age 60+10.7 years, range 21-89; 59.3% males) with AP, there were 247 (18.4%) patients (age 60.6 + 11.2, range 24-89, 59.1% males) with AA, including 58 (23.5%) patients with HGD (26, 9.2%), TVA/VA (40, 14.1%) and TA (9, 3.2%) as well as polyps > 10 mm in size;189 (76.5%) patients had only TA with a polyp size > 10 mm. There were more men (59.1%) than women with AA (p=0.024), and the highest prevalence (33.6%) of AA occurred in those aged 50-59 and with left-sided predominance (p=0.011). There was no difference in the distribution of AA between right and left-sided colon, regardless of patient's gender. During the same study period, there were 1,757 patients with CRC, with the highest frequency among patients 60-69 years and predominantly arising in the left colon. Conclusion: In the population described in our study, 18.4% of adenomatous polyps were advanced. AA were more common in men, peaking in ages 50-59 years with a clear left-side predominance. These distribution patterns correlated with those of CRC, but the peak prevalence occurred in patients 10 years younger. Disclosure: One author is employed by Caris Life Sciences.