Improved diagnostic stratification of digitised Barrett's oesophagus biopsies by TP53 immunohistochemical staining

Abstract

Aims

Interobserver agreement for dysplasia in Barrett's oesophagus (BO) is low and guidelines advise expert review of dysplastic cases. We assessed the added value of p53 immunohistochemistry (IHC) on the homogeneity within a group of dedicated gastro-intestinal (GI) pathologists.

Methods and results

Sixty single hematoxylin & eosin (HE) slide referral BO cases (20 low-grade dysplasia (LGD); 20 high-grade dysplasia (HGD) and 20 non-dysplastic BO (NDBO) reference cases) were digitalised and independently assessed twice in a random order by 10 dedicated GI pathologists. After a 'wash-out' period, cases were re-assessed with the addition of a corresponding p53 IHC slide. Outcomes were 1) proportion of 'indefinite for dysplasia' (IND) diagnoses, 2) interobserver agreement and 3) diagnostic accuracy compared to a consensus 'gold standard' diagnosis defined at an earlier stage by 5 core expert BO pathologists after their assessment of this case set. Addition of p53-IHC decreased the mean proportion of IND diagnoses from 10/60 to 8/60 (p=0.071). Mean interobserver agreement increased significantly from 0.45 to 0.57 (p=0.0021). The mean diagnostic accuracy increased significantly from 72% to 82% (p=0.0072) after addition of p53 IHC.

Conclusion

Addition of p53-IHC significantly improves the histological assessment of BE biopsies, even within a group of dedicated GI-pathologists. It decreases the proportion of IND diagnoses and increases interobserver agreement and diagnostic accuracy. This justifies the use of accessory p53 IHC within our upcoming national digital review panel for BO biopsy cases.

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