Research details

Lead name: Ahmir Ahmad ([email protected])

Research theme: Lower GI

Study region: London

Start (expected start date) and end (expected end date): From 1st February 2020 until 30th November 2021

Funding source: Commercial

Research Summary

The DISCARD3 study, conducted at St Mark’s National Bowel Hospital, evaluated the feasibility, safety, and cost-effectiveness of implementing optical diagnosis with resect and discard strategy in routine colonoscopy practice. The study focused on diminutive colorectal polyps (<5 mm), which make up the majority of polyps detected during screening but rarely carry malignant potential. Traditionally, all such polyps are resected and sent for histopathology, creating significant costs and delays. Optical diagnosis, by contrast, uses advanced endoscopic imaging to classify these lesions in real time, potentially avoiding unnecessary histology when the diagnosis is made with high confidence.

In DISCARD3, accredited bowel cancer screening colonoscopists underwent structured training and accreditation in optical diagnosis. Their in-procedure optical assessments were then compared with histopathology as the gold standard. The study assessed diagnostic accuracy, safety outcomes, and the potential economic and environmental benefits of adopting a resect-and-discard approach within the English Bowel Cancer Screening Programme (BCSP).

Findings demonstrated that when performed with high confidence, optical diagnosis met internationally recommended thresholds for diagnostic accuracy. The strategy was shown to be safe for patients, clinically effective, and capable of substantially reducing the need for histopathological analysis. Economic modelling confirmed significant cost savings for the NHS, while also reducing resource use and environmental impact.

DISCARD3 therefore provided pivotal evidence that supported NHS England’s decision to roll out optical diagnosis nationally within the BCSP. This made England the first country worldwide to embed a resect-and-discard policy into a national bowel screening programme. The study’s outcomes have generated international interest, highlighting how optical diagnosis can improve efficiency, reduce environmental burden, and sustain high standards of patient safety and cancer prevention.