Oral indigo carmine for the detection of colon adenoma

Abstract

Objectives

Colonoscopy is currently considered the optimal method to detect colorectal neoplasia; however, some adenomas remain undetected. While indigo carmine staining with a dye-spray catheter has demonstrated promising results for reducing the miss rate, we investigated the oral indigo carmine method. The aim of this study was to determine whether oral indigo carmine intake before standard colonoscopy increases the adenoma (and adenocarcinoma) detection rate (ADR) or the mean number of adenomas per patient (MAP).

Materials and methods

The oral indigo carmine method was performed from April 2018 to July 2020 in two hospitals. Data were collected in a prospective manner and compared to the conventional group whose data were collected retrospectively and consecutively from January 2016 to March 2018. All data were anonymized.

Results

Among the 704 patients included, colonoscopies were completely performed in 693 patients (347 in the indigo group). The ADR did not significantly differ between the groups: 42.3% vs. 40.3% (indigo vs. conventional group; odds ratio: 1.13; 95% confidence interval: 0.9–1.33, p = .33). The MAP was significantly greater in the indigo group (1.15) than that in the conventional group (0.82; p = .009). The cecal intubation rate and time to cecal intubation did not differ between the indigo and conventional group (98.6% vs. 98.3%, p = .83, and 6.2 min vs. 5.9 min, p = .39, respectively).

Conclusion

The routine use of oral indigo carmine does not lead to a higher ADR despite the higher MAP.

Keywords:

• Adenoma detection rate
• colonoscopy
• colorectal cancer
• indigo carmine
• mean adenoma per patient

Disclosure statement

The authors report no conflict of interest.

Author contributions

All authors contributed significantly towards the completion of this study. Study design, execution, data analysis, and manuscript writing: K. Kawanishi; data analysis: Y. Ikeda, M. Futotani, S. Tsuboi, T. Kanno, T. Niwa, T. Nagaoka, Y. Tabata, K. Hatamaru; administration and supervision: T. Maekita, M. Iguchi, and M. Kitano.

Data availability statement

The data that support the findings of this study are available from the corresponding author, KK, upon reasonable request.