Objective:

To evaluate the usefulness of indigo carmine spraying for detecting gastric cancer and gastric adenoma during upper gastrointestinal endoscopy in patients at high risk of gastric cancer.

Approach:

• Study Design: Prospective multicentre observational study involving over 30 institutions.
• Patient Inclusion: Patients aged 20-95 undergoing upper gastrointestinal endoscopy for surveillance or pretreatment screening will be enrolled.
• Observation Method: Two-step gastric observation: first with white light imaging, followed by a second-pass observation after indigo carmine spraying.
• Primary Endpoint: Proportion of patients with gastric cancer or adenoma detected during the second-pass observation.
• Statistical Analysis: One-sided binomial test (α=0.05) to compare detection rate with a predefined threshold of 1.0%.

Key Findings:

• Robust evidence supporting the effectiveness of indigo carmine chromoendoscopy in improving gastric cancer detection rates is limited.

Interpretation:

If successful, indigo carmine spraying may provide a simple screening strategy for early gastric cancer detection.

Limitations:

• Lack of consensus on routine endoscopic techniques across different platforms.
• Exclusion of patients with a history of oesophageal or gastric surgery.

Conclusion:

The study aims to determine if indigo carmine spraying increases detection rates of gastric cancer and adenomas.

Sources:

• INDIGO Study Protocol