Sometimes referred to as Kudo levels (not to be confused with Kudo classification of endoscopic appearances of polyps). Histological classification of the extent of invasion of sessile malignant colorectal polyps into the submucosa. Pedunculated lesions are classified separately using the Haggitt classification.
- Invasion of the superficial one-third of the submucosa
- Invasion of the middle one-third of the submucosa
- Invasion of the deep one-third of the submucosa
The three levels are associated with rates of lymph node metastases of 1-3%, 8% and 23% respectively.
Extension into the muscularis propria makes the tumour a pT2 cancer.