Association between index adenomas and advanced neoplasia at third surveillance colonoscopy: Data from the New Hampshire Colonoscopy Registry

Background: Due to a lack of data, the USMTSF does not provide guidance for the 3 rd surveillance exam for adenomas detected on index colonoscopy. Our aim was to assess advanced outcome risk at 3 rd surveillance in patients with index adenomas. Methods: We included patients from the New Hampshire Colonoscopy Registry with no genetic syndromes, inflammatory bowel disease, those with first degree relative with CRC < 50 years of age, adequate bowel preparation and no colorectal cancer (CRC) on index, and with three follow-up colonoscopies each >12 months apart. Only patients with normal or low risk findings (1-2 small TAs/SSPs) on 1 st and 2 nd surveillance exam were included. Individuals were stratified by index adenomas: no adenomas, 1-2 non-advanced adenomas (NAA), 3-4 NAA, 5+NAA and advanced adenomas. A Poisson model adjusting for age, sex, index serrated polyps, endoscopist adenoma detection rates and months to follow up exam (offset variable) predicting advanced neoplasia on 3 rd surveillance was performed. Results: Patients (n=1021) with an advanced adenomas on index were found to have a statistically significant increased risk of advanced neoplasia on 3 rd surveillance as compared to those patients with no adenomas (adjusted rate ratio=3.96(95%CI:1.96-7.98)). In addition, after adjusting for endoscopists ADRs, the RR was still statistically higher for this group (RR=3.00(95%CI:1.20–7.48)) Conclusion: Our data suggest that those with an advanced adenomas on index exam continue to have a statistically significant increased risk of advanced neoplasia on 3 rd surveillance. This finding supports close surveillance in patients with these lesions.