p53 immunohistochemistry in Barrett's biopsies: reproducible and decision-changing

Design

Nationwide consecutive consultation cohort with expert panel review

Population

1,146 Barrett's oesophagus cases (1,704 biopsy levels), Dutch Esophageal Pathology Panel

Primary outcome

Interobserver agreement and diagnostic reclassification with p53

Effect

Panel kappa 0.65 (95% CI 0.61–0.69); indefinite → low-grade dysplasia 37.1%

The Dutch Esophageal Pathology Panel reviews Barrett's oesophagus biopsies referred from hospitals across the Netherlands. This study, published in June, analysed 1,146 consecutive consultation cases (1,704 biopsy levels), each assessed by a median of 12 panel pathologists on H&E, on p53 pattern (wild-type, overexpression, double clone, null or equivocal) and on the two combined.

Agreement on p53 among 13 panel pathologists scoring 316 biopsies was substantial (kappa 0.65, 95% CI 0.61 to 0.69). Agreement between referring hospitals and the panel was moderate to substantial (kappa 0.61), and about a quarter of referring p53 calls were changed. p53 altered diagnoses in both directions: aberrant staining moved 9% of non-dysplastic biopsies to indefinite and 5% to low-grade dysplasia, while among indefinite biopsies 37% were reclassified as low-grade dysplasia and 17% as non-dysplastic.

The indefinite category is where p53 does most work, and it is the category that most often leads to repeat endoscopy without resolution. Laboratories reporting Barrett's biopsies can reasonably use p53 as an adjunct, provided pattern criteria — including null staining — are applied consistently. The study measured diagnostic change and reproducibility, not progression, and the panel's experts may read p53 more reliably than general laboratories.

• Consider adding p53 immunohistochemistry when a Barrett's biopsy is indefinite for dysplasia.
• Score all aberrant patterns, including null staining and double clones, not only overexpression.
• Use p53 as an adjunct to H&E, not as a stand-alone diagnosis of dysplasia.
• Seek expert review for dysplasia calls, as a quarter of referring p53 assessments were revised.
• Agree local p53 pattern criteria and audit concordance with a reference centre.

Why it matters

It gives the indefinite-for-dysplasia category, which drives repeat endoscopy, a reproducible way to resolve.

Don't overread it

The study shows reproducibility and diagnostic change, not that p53-guided diagnoses better predict progression.

The statistics, in plain English

Kappa measures agreement beyond chance: 0 is chance, 1 is perfect, and 0.61–0.80 is usually called substantial. A kappa of 0.65 among experts is good for a morphological test. The reclassification percentages show how often p53 changed the call, not whether the new call was right.

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