Development and Validation of a Computer-Aided Diagnostic System for Colorectal Lesions Based on the JNET Classification: Supporting the "Resect and Discard" Strategy.

OBJECTIVES

Although the Japan NBI Expert Team (JNET) classification for colorectal lesions is clinically useful, standardization remains challenging owing to endoscopist variabilities. Therefore, we developed a computer-aided diagnosis (CADx) system to support JNET diagnoses, potentially facilitating a "Resect and Discard" strategy. The CADx system's diagnostic performance and its potential to support the "Resect and Discard" strategy were compared with those of endoscopists of varying experience.

METHODS

Forty-three patients (60 lesions) who underwent CADx system colonoscopies at Hiroshima University Hospital between September 2022 and July 2024 were evaluated. Endoscopists were grouped by experience: beginners (100-500 cases, n=4), intermediates (1,000-2,000 cases, n=5), and experts (>2,000 cases, n=3). In Study 1, JNET classification concordance between the CADx system and beginner/intermediate endoscopists was compared, using expert diagnosis as the gold standard. Study 2 included 38 <10 mm lesions, with histopathology as the gold standard. Lesions excluding advanced neoplasia were classified as "Resect and Discard". The CADx system and endoscopists were evaluated for identifying JNET Type 1 and 2A lesions as non-advanced neoplasia.

RESULTS

In Study 1, CADx-expert concordance was 83.3% (Kappa=0.75)-significantly higher than beginners (66.7%) and outperforming intermediates (78.0%). In Study 2, the CADx system's accuracy was 92.1%-significantly higher than beginners (70.4%) and outperforming intermediates (82.6%) and experts (78.9%). The CADx system's advanced neoplasia negative predictive value was 100%.

CONCLUSIONS

The CADx system showed high concordance with expert diagnoses. For lesions <10 mm, its high advanced neoplasia diagnostic accuracy indicates its potential utility in supporting the "Resect and Discard" strategy.