Loose/Thick vessels; Amorphous surface. (Deep SM Invasion)
Clinical Prediction
01
Type 1/2A: Low risk of malignancy; treat with standard endoscopic resection (EMR/Polypectomy).
02
Type 2B: High risk of HGD; ESD is preferred for en-bloc pathology.
03
Type 3: Deep invasion (> 1000µm); Surgery is mandatory.
Section 3
Pearls/Pitfalls
JNET vs. NICE
The NICE classification is for "Non-Magnified" NBI (easier for generalists). The JNET classification is for "Magnified" NBI (standard for specialists). JNET 2B is the critical "grey zone" that requires expert ESD to ensure a curative result if superficial invasion is found.
The Search for Type 2B
Identifying Type 2B features (irregular vascularity) within a larger 2A lesion is the hallmark of advanced colonoscopy. These focal "hotspots" often harbor the cancer and must be targeted for biopsy or included in the resection margin.
Clinical Pearls
Type 1 lesions in the rectosigmoid < 5mm can often be ignored or "discarded" under the PIVET policy
Type 3 has a > 95% specificity for deep submucosal invasion
Vessel pattern is often easier to interpret than surface pattern in a bloody or poorly-prepped field
Section 4
Next Steps
Treatment Strategy
01
Type 1: Cold Snare Polypectomy or Leave-in-situ (if < 5mm distal).
02
Type 2A: EMR or Snare Polypectomy.
03
Type 2B: Referral for ESD.
04
Type 3: Surgery Staging.
Complementary Tools
Kudo Pit Pattern Interpretation
NICE Classification (Non-magnified NBI)
Paris Classification (Morphology)
Section 5
Evidence Appraisal
The JNET Validation
Narrow-band imaging (NBI) magnifying classification for colorectal tumors proposed by the Japan NBI Expert Team.
Sano Y et al. • Digestive Endoscopy. 2016;28(5):526-33. The primary consensus document.
Developed by the Japan NBI Expert Team (JNET) – a group of leading endoscopists tasked with unifying the three major competing NBI classifications (Sano, Hiroshima, and Showa) into a single global standard.
