What makes an expert Barrett’s pathologist? Concordance and pathologist expertise within a digital review panel

This thesis describes the set-up of the national digital review panel for histopathologic evaluation of dysplastic Barrett’s esophagus (BE). This is the first pathologist expert panel worldwide in which the 16 participants were trained to attain a pre-defined gold standard of assessment quality. Over the course of five years, they assessed 31,500 slides and diagnosed over 6,000 cases.
BE is a pre-malignant condition in which the stratified squamous epithelium of the distal esophagus is replaced by metaplastic columnar epithelium containing goblet cells. Patients are at increased risk of developing esophageal adenocarcinoma, a deadly cancer with a 5-year survival rate of 15%. The risk of progression to high-grade dysplasia/carcinoma depends on dysplasia grade. Non-dysplastic BE carries a low progression risk (0.1-0.5% per patient-year), while BE with low-grade dysplasia carries a significantly higher risk (~9% per patient-year). To monitor dysplasia development, BE patients undergo regular endoscopies with histopathological biopsy assessment. Especially low-grade dysplasia, (the middle of the spectrum), can be challenging to diagnose for a general pathologist. Correct stratification of these patients according to diagnostic category is important, however, because surveillance interval and treatment decisions depend on it. It is known from literature that an expert BE pathologist is able to accurately stratify these patients. Therefore, all BE guidelines state that dysplastic BE biopsies should be reviewed by a second, expert BE pathologist. In order to increase BE expertise on a national level and streamline review requests, it was decided to set up a national digital review panel to meet the increasing need for BE biopsy review.