Diagnostic performance for T1 cancer in colorectal lesions ≥10 mm by optical characterization using magnifying narrow-band imaging combined with magnifying chromoendoscopy; implications for optimized stratification by Japan Narrow-band Imaging Expert Team classification.

ABSTRACT

BACKGROUND: Magnifying narrow-band imaging (M-NBI) and magnifying chromoendoscopy (M-CE) enable accurate diagnosis of T1 colorectal cancer, but the diagnostic yields from combined M-NBI and CE have not been fully analyzed. We aimed to evaluate the diagnostic yield of combining Japan NBI Expert Team (JNET) classification using M-NBI and M-CE. METHODS: Superficial colorectal lesions ≥10 mm removed at a Japanese tertiary cancer center between February 2016 and December 2018 were included. We analyzed the relationship between JNET classification, M-CE findings, and histological results based on prospectively collected endoscopic and pathologic data. RESULTS: A total of 1573 lesions, including 56 superficial submucosal invasive cancers, 160 deep submucosal invasive cancers, and 81 advanced cancers (≥T2) were analyzed. The probability of deeply invasive cancer (95% confidence interval) was 1.8% (1.1-2.8), 30.1% (25.4-35.1), and 96.6% (91.5-99.1) in JNET Types 2A, 2B, and 3, respectively. The probability of deeply invasive cancer in JNET Type 2B lesions with non-V, VL, and VH pit pattern was 4.3%, 16.6%, 76.0%, respectively (P < 0.001). CONCLUSIONS: Our study showed the stratification by M-NBI using JNET classification and the effect of additional M-CE for JNET Type 2B lesions.