Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Lerch, J.
Interobserver variability in subtyping and estimating the extent of gastric intestinal metaplasia in patients with chronic atrophic gastritis
Humanmedizin; [ Diplomarbeit ] Medizinische Universität Graz; 2021. pp. 133
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Langner Cord
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- Abstract:
- Background: Extensive gastric intestinal metaplasia (GIM) and the incomplete subtype are associated with an increased risk of gastric cancer. The extent and subtype of GIM may therefore be utilized in the risk stratification of patients with gastric precancerous lesions. Aims: This diploma thesis aimed to examine the interobserver variability of subtyping GIM (incomplete versus complete) in the histological diagnosis of patients with chronic atrophic gastritis. As a secondary objective, interobserver variability in the estimation of the percental extent of GIM was investigated. Parameters with potential impact on the assessment and the clinical consequences of misclassification were evaluated. Methods: Nine international gastrointestinal expert pathologists assessed 46 cases with complete, incomplete or mixed-type GIM on scanned haematoxylin and eosin-stained slides. Results were compared with the consensus diagnosis driven by two experts. Interobserver variability was evaluated by applying kappa statistics. Additionally, all eleven pathologists were included in a secondary analysis on the interobserver variability of estimating the overall percental extent of GIM. Interobserver agreement was calculated with the intraclass correlation coefficient (ICC). Results: Regarding the predominant GIM pattern (predominant complete versus predominant incomplete GIM), the agreement between each observer and the consensus diagnosis ranged from 78% to 98%. Kappa statistics showed a moderate to almost perfect level of agreement (weighted kappa=0.464-0.984). The overall agreement of the participating pathologists can be classified as substantial (Fleiss’ kappa=0.716, 95% confidence interval: 0.677-0.755). Misclassification with impact on clinical decision-making occurred in 19 out of 333 (5.7%) of case ratings. Agreement in cases with pure GIM was significantly higher than in cases with mixed-type GIM (p=0.010). Pathologists who apply subtyping in daily routine performed better than those who do not (p=0.040). The interobserver agreement in estimating the percental extent of GIM was very good (ICC 0.983, 95% confidence interval: 0.975-0.990). Conclusion: In conclusion, subtyping and estimating the percental extent of GIM on haematoxylin and eosin-stained slides can be achieved with high interobserver agreement among gastrointestinal expert pathologists. The implementation of GIM subtyping as a risk-stratifying tool in current practice guidelines by the European Society of Gastrointestinal Endoscopy (ESGE) and the American Gastroenterological Association (AGA) carried a low rate of misclassification within this study. This diploma thesis provides the basis for future research in the field, e.g., by expanding the evaluation to general pathologists in a nation-wide setting, and for the potential implementation of percental GIM assessment in the respective guidelines on gastric precancerous lesions.