Interlaboratory variability in the grading of dysplasia in a nationwide cohort of colorectal adenomas

Kuijpers, C. C. H. J., Sluijter, C. E., von der Thüsen, J. H., Grünberg, K., van Oijen, M. G. H., van Diest, P. J., Jiwa, M., Nagtegaal, I. D., Overbeek, L. I. H. & Willems, S. M., Aug-2016, In : Histopathology. 69, 2, p. 187-97 11 p.

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  • Interlaboratory variability in the grading of dysplasia in a nationwide cohort of colorectal adenomas

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  • Chantal C H J Kuijpers
  • Caro E Sluijter
  • Jan H von der Thüsen
  • Katrien Grünberg
  • Martijn G H van Oijen
  • Paul J van Diest
  • Mehdi Jiwa
  • Iris D Nagtegaal
  • Lucy I H Overbeek
  • Stefan M Willems

AIMS: Although high-grade dysplasia (HGD) is a risk factor for malignant transformation and the future development of adenomas/carcinomas, grade is not incorporated in the Dutch guidelines for colonoscopy surveillance, partly because of presumed interobserver variability. The aim of this study was to analyse, in a nationwide cohort of colorectal adenomas, the interlaboratory variability in the grading of dysplasia in daily practice.

METHODS AND RESULTS: From the Dutch Pathology Registry, all synoptically reported classic adenomas in The Netherlands in 2013 were identified. The proportion of adenomas with HGD was determined for biopsies and polypectomies, and compared between 37 laboratories by the use of multivariable logistic regression analyses. In total, 21 030 colonoscopies of 20 270 patients were included. HGD was reported in 530 (3.6%) of 14 866 adenomas diagnosed on biopsies (range between laboratories: 0-13.6%) and in 983 (11.8%) of 8346 adenomas diagnosed on polypectomies (range: 3.1-42.9%). After adjustment for case mix, 13 (35%) laboratories reported a significantly lower or higher frequency of HGD than average.

CONCLUSIONS: We observed considerable interlaboratory variation in the grading of dysplasia in colorectal adenomas, which could be only partly explained by differences in case mix. Therefore, better standardization of grading criteria is needed before grade of dysplasia can usefully be incorporated in colonoscopy surveillance guidelines.

Original languageEnglish
Pages (from-to)187-97
Number of pages11
Issue number2
Publication statusPublished - Aug-2016
Externally publishedYes


  • Adenoma/classification, Aged, Biopsy, Carcinoma/classification, Cohort Studies, Colonic Polyps/classification, Colonoscopy, Colorectal Neoplasms/classification, Female, Humans, Hyperplasia/classification, Male, Netherlands, Observer Variation, Risk Factors, Surveys and Questionnaires

ID: 124017982