Table 2.

Summary of major tumor regression grade systems in use

Score	Dworak, et al. (score 0–4) [23]	American Joint Committee on Cancer (score 0–3) [26]	Mandard, et al. (score 1–5) [27]	Memorial Sloan Kettering CC (score 1–3) [29]
TRG 0	Minimal tumor response to treatment	No residual tumor cells	–	–
TRG 1	Fibrosis in <25 % of tumor	Single or small group of cells	No residual tumor cells	No residual tumor cells
TRG 2	Fibrosis in 25–50 % of tumor	Cancer with fibrotic response	Rare cancer cells	86–99 % tumor response
TRG 3	Fibrosis in >50 % of tumor	Minimal tumor response to treatment	Fibrosis > residual cancer	≤85 % tumor response
TRG 4	No residual tumor cells	–	Residual cancer > fibrosis	–
TRG 5	–	–	Minimal tumor response to treatment	–

TRG tumor regression grade