Interobserver agreement of the modified Paris classification and histology prediction of colorectal lesions in patients with inflammatory bowel disease

Post written by Nayantara Coelho-Prabhu, MD, Associate Professor of Medicine from the Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA.


This study was performed to assess the interobserver variability in application of the recommended Paris classification to describe the morphology of visible dysplasia in inflammatory bowel disease (IBD) colonoscopies.

There is a lack of standardized reporting for the morphology of visible dysplastic lesions in patients with IBD. The description is important because certain morphologies have been reported to be associated with poorer prognosis and higher grades of dysplasia. Currently, guidelines recommend using the Paris classification, but in clinical practice significant variability is found.

To our knowledge, our study is the first to report on interobserver variability of the Paris classification in IBD dysplastic lesions. We present poor consensus for Paris and modified Paris classification, Light’s kappa coefficient values of .42 with the lowest consensus for lesions Is or IIa, where the difference between these categories was < or ≥2.5 mm in lesion height.

Our results show that this assessment of height of the lesion is very difficult to standardize. We also found that both types of lesions were more likely to be dysplastic, suggesting that this differentiation in categories is unnecessary.

In addition, we discovered increasing variability in size prediction with increasing size. We also observed that, for nonpedunculated lesions, endoscopists were more likely to predict dysplasia in flat lesions that ultimately had a serrated epithelial change or were hyperplastic at pathology.

Thus, endoscopists were unable to predict histology well in these lesions, and this is an area where work is necessary to help identify only high-risk lesions needing to be removed at endoscopy. We anticipate machine learning, once developed with large datasets, can help us, especially if correlated with ground-truth histopathology.

Coelho-Prabhu_figureExamples of endoscopic images with no consensus for Paris classification and modified Paris classification among raters. Disagreement stands out for lesions with “mixed morphology” (top) and “minimally elevated” lesions (bottom).

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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