Table1.

TNM classification of duodenal cancer, based on the UICC 8th edition of small intestine cancer

Degree of progression	TNM classification
Epithelial	Tis
Local	T1a (invades lamina propria/muscularis mucosa), T1b (submucosa)
	T2 (muscularis propria)
	T3 (involvement of submucosa/peri-muscular tissue)
Regional lymph node metastasis	N1-2
Proximal organ invasion	T4 (penetrates visceral peritoneum/invades other organs and structures)
Distant metastasis	M1

UICC Union for International Cancer Control