Disagreement between high confidence endoscopic adenoma prediction and histopathological diagnosis in colonic lesions ≤ 3 mm in size

Abstract

Background Diminutive colorectal polyps resected during colonoscopy are sometimes histologically interpreted as normal tissue. The aim of this observational study was to explore whether errors in specimen handling or processing account in part for polyps ≤ 3 mm in size being interpreted as normal tissue by pathology when they were considered high confidence adenomas by an experienced endoscopist at colonoscopy. Methods One endoscopist photographed 900 consecutive colorectal lesions that were ≤ 3 mm in size and considered endoscopically to be high confidence conventional adenomas. The photographs were reviewed blindly to eliminate poor quality images. The remaining 644 endoscopy images were reviewed by two external experts who predicted the histology while blinded to the pathology results. Results Of 644 consecutive lesions ≤ 3 mm in size considered high confidence conventional adenomas by a single experienced colonoscopist, 15.4 % were reported as normal mucosa by pathology. The prevalence of reports of normal mucosa in polyps removed by cold snare and cold forceps were 15.2 % and 16.0 %, respectively. When endoscopy photographs were reviewed by two blinded outside experts, the lesions found pathologically to be adenomas and normal mucosa were interpreted as high confidence adenomas by endoscopic appearance in 96.9 % and 93.9 %, respectively, by Expert 1 (P = 0.15), and in 99.6 % and 100 %, respectively, by Expert 2 (P = 0.51). Conclusion Retrieval and/or processing of tissue specimens of tiny colorectal polyps resulted in some lesions being diagnosed as normal tissue by pathology despite being considered endoscopically to be high confidence adenomas. These findings suggest that pathology interpretation is not a gold standard for lesion management when this phenomenon is observed.

Use of Endoscopic Impression, Artificial Intelligence, and Pathologist Interpretation to Resolve Discrepancies Between Endoscopy and Pathology Analyses of Diminutive Colorectal Polyps

“…From April 2016 to August 2017 consecutive colorectal lesions ≤ 3mm, diagnosed during optical evaluation as adenatomous with high-confidence by a single experienced endoscopist with expertise in optical evaluation (DKR), were considered for inclusion (5) . A size restriction of ≤ 3mm was selected, as these lesions were perceived to have a substantial risk of failed pathologic identification.…”

“…This discrepancy is of critical importance, given its inherent effect on surveillance colonoscopy recommendations (4) , and therefore its potential impact on interval colorectal cancer. In a recent study by Ponugoti and colleagues (5) , 644 consecutive colorectal lesions ≤ 3mm were diagnosed as adenomas with highconfidence by an experienced endoscopist with expertise in optical evaluation. On pathology, 15.4% were diagnosed as normal mucosa.…”

Machine learning in GI endoscopy: practical guidance in how to interpret a novel field

“… 10 20 21 It should however be noted that histology might not always be the preferred gold standard for CADx systems, for example, due to sampling error and interobserver variability between pathologists. 22 For example, in certain circumstances, optical biopsies by experts might be preferred over pathology assessment.…”

Challenges for the crosstalk between endoscopists and pathologists

“…Diminutive colorectal polyps resected during endoscopy may sometimes by classified as normal tissue by pathologists, and this issue represents an important topic for the interdisciplinary crosstalk between endoscopists and pathologists. In this issue of Endoscopy, Ponugoti et al [1] report on the disagreement between endoscopic and histological diagnoses of diminutive colon polyps. They compared 644 consecutive polyps ≤ 3 mm in size using endoscopic criteria and pathological assessment, and identified discrepancies in the classification and interpretation of such lesions.…”

“…The recommendation that "when a high confidence adenoma is identified endoscopically and documented by photography, and the pathology report returns as normal, it is reasonable to manage the patient as if they had a conventional adenoma" is a pragmatic interpretation of the results [1]. However, more intense communication may resolve the situation.…”