Table 1.

Criteria of five tumor regression grading systems

TRG system	Grade	Description
Mandard-TRG	1	No residual cancer
	2	Rare residual cancer cells
	3	Fibrosis outgrowing residual cancer
	4	Residual cancer outgrowing fibrosis
	5	Absence of regressive changes
JGCA-TRG	0	No evidence of effect
	1a	Viable tumor cells occupy more than 2/3 of the tumorous area
	1b	Viable tumor cells remain in more than 1/3 but less than 2/3 of the tumorous area
	2	Viable tumor cells remain in less than 1/3 of the tumorous area
	3	No viable tumor cells remain
CAP-TRG	0	No viable cancer cells (complete response)
	1	Single cells or small groups of cancer cells (moderate response)
	2	Residual cancer outgrown by fibrosis (minimal response)
	3	Minimal or no tumor killed or extensive residual cancer (poor response)
China-TRG	Severe response	Tumor cells completely disappear or very few highly regressive residue exist with obvious scarring and varying inflammation
	Moderate response	Most tumor cells degenerate and necrosis with obvious stroma fibrosis and inflammation
	Mild response	Absence of or slight necrosis and degeneration of tumor cells accompanied by mild stroma fibrosis and inflammation
Becker-TRG	1a	No residual tumor/tumor bed
	1b	<10% residual tumor/tumor bed
	2	10–50% residual tumor/tumor bed
	3	>50% residual tumor/tumor bed