Grading of dysplasia in Barrett's oesophagus: Substantial interobserver variation between general and gastrointestinal pathologists
Aims: To determine interobserver variation in grading of dysplasia in Barrett's oesophagus (BO) between non-expert general pathologists and expert gastrointestinal pathologists on the one hand and between expert pathologists on the other hand. Methods and results: In this prospective multicentre study, non-expert and expert pathologists graded biopsy specimens of 920 patients with endoscopic BO, which were blindly reviewed by one member of a panel of expert pathologists (panel experts) and by a second panel expert in case of disagreement on dysplasia grade. Agreement between two of three pathologists was established as the final diagnosis. Analysis was performed by κ statistics. Due to absence of intestinal metaplasia, 127/920 (14%) patients were excluded. The interobserver agreement for dysplasia [no dysplasia (ND) versus indefinite for dysplasia/low-grade dysplasia (IND/LGD) versus high-grade dysplasia (HGD)/adenocarcinoma (AC)] between non-experts and first panel experts and between initial experts and first panel experts was fair (κ = 0.24 and κ = 0.27, respectively), and substantial for differentiation of HGD/AC from ND/IND/LGD (κ = 0.62 and κ = 0.58, respectively). Conclusions: There was considerable interobserver variability in the interpretation of ND or IND/LGD in BO between non-experts and experts, but also between expert pathologists. This suggests that less subjective markers are needed to determine the risk of developing AC in BO.