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Interlaboratory variability in the grading of dysplasia in a nationwide cohort of colorectal adenomas
Author(s) -
Kuijpers Chantal C H J,
Sluijter Caro E,
Thüsen Jan H,
Grünberg Katrien,
Oijen Martijn G H,
Diest Paul J,
Jiwa Mehdi,
Nagtegaal Iris D,
Overbeek Lucy I H,
Willems Stefan M
Publication year - 2016
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.12923
Subject(s) - medicine , grading (engineering) , dysplasia , colonoscopy , cohort , logistic regression , colorectal cancer , adenoma , cohort study , gastroenterology , cancer , civil engineering , engineering
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.