Clinical Report: Evaluating the Efficacy of Indigo Carmine Chromoendoscopy

Background

Gastric cancer is often diagnosed at advanced stages due to subtle mucosal changes that can be overlooked during routine endoscopy. Indigo carmine chromoendoscopy has been used in Japan for decades to improve detection of early gastric neoplasia, yet its effectiveness remains inadequately supported by robust evidence. This study aims to clarify the role of indigo carmine in enhancing detection rates in high-risk patients.

Data Highlights

This study will enroll over 1050 patients across more than 30 institutions, utilizing a two-step observation process during upper gastrointestinal endoscopy. The primary endpoint is the proportion of patients with detected gastric cancer or adenomas during the second-pass observation after indigo carmine application.

Key Findings

• The study will assess the effectiveness of indigo carmine chromoendoscopy in detecting gastric cancer and adenomas.
• It aims to determine if the detection rate exceeds a predefined threshold of 1.0%.
• Patients aged 20 to 95 years at high risk for gastric cancer will be included.
• The study has received ethical approval and will ensure informed consent from participants.
• Indigo carmine has been historically used in Japan since the 1970s for upper gastrointestinal endoscopy.

Clinical Implications

If successful, indigo carmine chromoendoscopy may provide a straightforward and effective screening method for early gastric cancer detection, potentially influencing clinical practice guidelines. The findings could support the integration of this technique into routine endoscopic evaluations for high-risk patients.

Conclusion

This study is poised to contribute valuable data on the utility of indigo carmine chromoendoscopy in enhancing the detection of gastric neoplasia.

Related Resources & Content

1. Kanagawa Cancer Center, INDIGO Study, 2025 -- Evaluating the Efficacy of Indigo Carmine Chromoendoscopy
2. Techniques in Coloproctology — Fluorescence-guided lymph node mapping using indocyanine green for assessing resection margins in colon cancer: Findings from the ISCAPE study
3. Surgical Endoscopy — Utilization of Indocyanine Green and Near-Infrared Fluorescence for Identifying Metastatic Lymph Nodes in Oesophageal and Gastric Cancer Resection: A Systematic Review and Meta-Analysis
4. Journal of Gastroenterology — Diagnostic performance of magnifying endoscopy with third-generation narrow-band imaging for early gastric cancer: post hoc analysis of a randomized trial (3G detection trial)
5. Journal of Gastroenterology — An Overview of Linked Color Imaging in Gastric Cancer Screening: Current Insights and Future Directions
6. 2025 ESGE/EHMSG/ESP MAPS III guideline
7. 2025 ACG Clinical Guideline on Gastric Premalignant Conditions
8. Diagnostic performance of white light endoscopy, narrow band imaging, and flexible spectral imaging color enhancement for early gastric cancer: a systematic review and meta-analysis - PubMed
9. Endoscopic detection and diagnosis of gastric cancer using image‐enhanced endoscopy: A systematic review and meta‐analysis - Dohi - 2025 - DEN Open - Wiley Online Library
10. Assessment of early gastric cancer visibility in deep-learning-based virtual indigo carmine chromoendoscopy (with video) - PMC
11. Chromoendoscopy | Johns Hopkins Medicine