The Bowel Cancer Screening Programme Expert Board: an analysis of activity during 2017-2020

Area of Science:

• Gastrointestinal Pathology
• Cancer Screening
• Diagnostic Accuracy

Background:

• The National Health Service Bowel Cancer Screening Programme faces challenges in differentiating epithelial misplacement from adenocarcinoma in colorectal adenomas.
• An Expert Board (EB) was established to review complex cases with a panel of gastrointestinal pathologists.

Purpose of the Study:

• To review the performance of the pathology Expert Board (EB) over a four-year period (2017-2020).
• To assess diagnostic agreement within the EB and between the EB and referring pathologists.

Main Methods:

• Analysis of 430 colorectal polyps referred to the EB by 193 pathologists from 76 hospitals.
• Evaluation of diagnostic concordance using kappa scores and review of diagnostic changes.

Main Results:

• The EB reached a consensus diagnosis for 97% of cases (67% benign, 28% malignant, 2% equivocal).
• The most significant diagnostic shift was from malignant to benign (50% of initially malignant cases).
• Intra-EB agreement was 'good' (kappa=0.619), while agreement with referring diagnoses was 'poor' (kappa=0.149).

Conclusions:

• Diagnostic agreement among EB members surpasses agreement with initial referring diagnoses.
• A consistent trend of downgrading malignant diagnoses to benign was observed by the EB.