Predicting Surgical Referral After Large Polypectomy

Abstract

Introduction: Resection of large polyps (defined as greater than 20 mm) has increasingly been performed by endoscopic mucosal resection (EMR) over recent years. However, polyp characteristics that predict likelihood of need for surgical resection remain unclear. The aim of this study is to determine the frequency, risk factors, and outcomes of patients referred for surgical resection of large colorectal polyps. Methods: This study is a single-center retrospective chart review of patients that underwent large polypectomies from 1/2004 to 1/2014. It included 179 patients with a total of 181 large polypectomies that were referred to colonoscopy for any reason. The primary outcome was the proportion of patients undergoing colorectal surgery for resection of large polyps. Univariate analysis was used to identify risk factors that predict surgical referral. Results: Out of a total of 181 large polypectomies, 42 (23%) were referred to surgery. 43% of these polyps were referred to surgery because they could not be completely resected by EMR. Factors that were associated with surgical referral for polyp resection included size >25 mm: 90/118 (76%) EMR polyps vs. 40/42 (95%) surgical polyps, p=0.011; and high-grade pathology defined as villous and high-grade dysplasia: 44/118 (37%) EMR polyps vs. 27/42 (64%) surgical polyps, p=0.003. Other characteristics such as patient age, sex, BMI>30 kg/m2, polyp location, and morphology were not associated with endoscopist referral to surgery. There was no difference in method of resection (en bloc vs. piecemeal) and no increase in adverse events in polypectomies that were attempted prior to surgical referral. 95% of high-grade lesions were known to have advanced pathology prior to surgical referral. Lastly, a significantly greater number of patients referred to surgery went on to develop colorectal cancer since their initial colonoscopy than those managed by EMR alone (p =< 0.001).Table 1: Statistically significant risk factors for surgical referralTable 2: Characteristics that do not predict surgical referralFigure 1Conclusion: Resecting large polyps endoscopically is a safe procedure, however recognizing characteristics that predict need for surgery is imperative. This study shows that lesions that are larger than 25mm and have high-grade pathology are more likely to require surgical resection. Further, the increased rate of progression to malignancy of those polyps referred to surgery suggests that endoscopists are successful in recognizing polyps with high malignant potential.