Endoscopic mis-sizing of polyps changes colorectal cancer surveillance recommendations.

Background: Adenomatous polyps greater than 1 cm are defined as advanced adenomas. Inaccurate size estimation can lead to inappropriate surveillance recommendations of colorectal adenomas.

Objective: The aim of this study was to determine the impact of endoscopic polyp mis-sizing on colorectal cancer surveillance recommendations.

Design: This is a prospective study.

Setting: This study was conducted in a gastroenterology practice at a US academic medical center.

Patients: Patients undergoing colorectal cancer screening and surveillance colonoscopies from 2010 to 2011 were included.

Main Outcome Measurements: Endoscopic size estimates of polyps 10 to 25 mm were compared with postfixation histopathologic polyp measurements for 15 different gastroenterologists. Only adenomatous polyps removed in entirety by snare polypectomy were included in the analysis. Size variation was defined as (endoscopic estimate - histopathologic size)/(histopathologic size). Clinical mis-sizing was defined as a size variation of >33%. The mean size variation, the percentage of clinical mis-sizing, and the percentage of inappropriate surveillance recommendation due to size variation >33% were reported per endoscopist.

Results: : Included for analysis were 4990 procedures from 15 gastroenterologists. A total of 230 polyps from 200 patients met inclusion criteria. The average age was 62.6 years (SD 10.1), and 52% were men. The mean size variation between the endoscopic polyp size estimation and the histopathologic polyp was 73.6% (range of mean size variation, 13%-127%). 62.6% (range, 0%-91%) of included polyps had clinical mis-sizing. Of included polypectomies, 35.2% (range, 0%-67%) resulted in an inappropriate surveillance recommendation due to clinical mis-sizing even after considering histology and synchronous polyps.

Limitations: This was a single-center study.

Conclusions: There is marked variation in endoscopists' ability to accurately size adenomatous polyps. Some endoscopists rarely mis-size adenomas, and their surveillance recommendations are appropriate in regard to sizing. However, other endoscopists inaccurately size adenomas, and this leads to inappropriate surveillance of colorectal polyps. In this study, approximately 1 of 3 included polypectomies yielded inappropriate surveillance recommendations because of clinical mis-sizing.