Retrospective Analysis of Site and Pathological Characteristics of Recurrence in Patients with Adenomatous Colonic Polyps

Aim: The benefits of colonoscopy surveillance in reducing the incidence and mortality of colorectal cancer are known. However, benefit may be driven by early detection of left side colon lesions to a greater extent than right side counterparts. The correlation between initial (“index”) adenoma(s) location, recurrent polyp(s) and their respective pathologic grade is not well understood. The purpose of this study was to determine if index colonic adenoma polypectomy location (right vs. left) correlated with recurrent adenoma location and polyp pathology.
Methodology: Retrospective review of patient medical records including all cases of completely resected adenomatous polyp(s) without evidence of dysplasia at initial colonoscopy with repeat follow-up study between November 1998 and August 2009 was performed at a tertiary level academic hospital. The splenic flexure was used to discriminate right vs. left side colon polyps.
Results: Records of 112 patients (53.6% males) with index adenomatous colonic polyps who had follow-up complete colonoscopy with polypectomy were reviewed. Mean (SD) time of follow-up colonoscopy was 43.3 (22.6) months. The mean age at presentation was 59.5 years. Initial polyp site was found on the right in 46 patients (41.1%), left in 38 (33.9%), and both right and left in 28 patients (25.0%). Patients with right side index adenomas were significantly older compared to those with left side lesions, with a mean (SD) age of 61.2 (9.9) vs. 55.6 (7.3) years respectively (p=0.008). Polyp pathology on follow-up colonoscopy revealed 16 (14.3%) hyperplastic, 84 (75.0%) adenomatous, 6 (5.4%) tubulovillous, 5 (4.5%) high grade dysplasia (HGD), and 1 (0.9%) cancer case. 28 of 39 right side index adenomas (71.8%), and 24 of 33 left side index adenomas (72.7%) had same side adenomatous or higher grade pathologic recurrence. Ipsilateral recurrence proved to be statistically significant (p<0.001). In addition, right side index adenomatous polyps had higher rates of adenomatous polyp recurrence (44/46, 95.7%) compared to left side index ones (26/38, 68.4%), independent of recurrence site (p<0.001).
Conclusion: Initial adenomatous polyp side may predict recurrent adenomatous location and polyp pathologic grade. Follow-up endoscopic surveillance methods and intervals should consider side of previous adenomatous polyp location.