Effect of Blink-Based Training on Cancer Detection in Colorectal Polyp Images by Medical Students/Non GI-trainees

Background and Rationale:

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality in Western countries, though it is largely preventable by detecting and removing precursor lesions such as colorectal polyps. While most polyps are small and benign, 1-2% are large (≥20 mm) non-pedunculated colorectal polyps (LNPCPs), which carry a markedly higher risk of invasive cancer (reported rates 6-15%, depending on morphology, histology, and location).

Accurate optical diagnosis of cancer in LNPCPs is critical for guiding treatment strategy-piecemeal endoscopic resection, en bloc resection, or surgery. However, endoscopists often underperform in identifying cancer within these lesions. Studies have reported correct cancer identification rates as low as 20-40%, even among trained endoscopists, contributing to unnecessary surgeries for benign polyps and missed diagnoses in malignant cases.

One contributing factor is the complexity of existing classification systems, which are rarely applied consistently in clinical practice. Simplified tools may improve accuracy and applicability.

The Blink framework, inspired by Malcolm Gladwell's concept of rapid, intuitive decision-making and aligned with Kahneman's System 1 thinking, condenses cancer recognition into six easily observed features of LNPCPs:

Fold deformation Extra redness Chicken skin mucosa Depression Spontaneous bleeding Ulceration

These Blink features can be recognized without advanced imaging and provide a structured, intuitive framework for rapid cancer detection. Previous research has shown that teaching these features improves endoscopists' diagnostic sensitivity. Building on this, the present study evaluates whether a brief Blink-based intervention can improve cancer detection among medical students and non-GI trainees with no prior training in polyp morphology.

Primary Objective:

To assess whether a short educational intervention (2-minute training video on Blink features) improves the sensitivity of medical students and non-GI trainees in detecting cancer in colorectal polyps using static images.

Secondary Objectives

• To evaluate changes in specificity, self-reported confidence, and interobserver agreement before and after the intervention.
• To identify which Blink features are associated with accurate cancer detection.
• To assess the relationship between the number of Blink features identified and diagnostic accuracy.

Study Design:

Design: Prospective interventional study with pre- and post-intervention assessments.

Setting: Online survey distributed to medical students and non-GI trainees affiliated with the Vrije Universiteit Brussel.

Intervention: 2-minute video training on the six Blink features, followed by re-assessment of images.

Target Population:

Medical students and non-GI trainees affiliated with the Vrije Universiteit Brussel without prior endoscopy experience.

Sample size: 50-100 participants (yielding 1,000-2,000 individual image evaluations).

Inclusion criteria

• Images of large non-pedunculated colorectal polyps (LNPCPs) obtained from patients who have provided informed consent for the anonymous use of polyp images during colonoscopy (EC-2024-200).
• Medical students and non-GI trainees who have provided written informed consent to participate in the study.

Exclusion criteria

• Participants (students or non-GI trainees) with prior experience in endoscopy or polyp detection, or those who do not provide informed consent.
• Images deemed to be of insufficient quality by the principal investigator.
• Patients who do not provide informed consent for image use and data collection.