Emerging aspects of oesophageal and gastro-oesophageal junction cancer histopathology – an update for the surgical oncologist

Table 6 Classification systems to grade tumour response to neo-adjuvant chemo-radiotherapy

Reference, Name of classification system		Details/definition
Mandard et al [103]; Tumour regression grade (TRG)	TRG1	Complete pathological regression: absence of residual cancer and fibrosis extending through the layers of the oesophageal wall
	TRG2	Presence of rare residual cancer cells scattered through the fibrosis
	TRG3	Increase in the number of residual cancer cells, but fibrosis still predominant
	TRG4	Showing residual cancer outgrowing fibrosis
	TRG5	Absence of regressive changes
Chirieac et al [101]; Residual carcinoma status	0	No residual cancer
	1	1% to 10% residual cancer
	2	11%–50% residual cancer
	3	>50% residual cancer
General rules for oesophageal cancer proposed by the Japanese Society for Esophageal Disease [120] *	Complete response	Disappearance of the primary tumour in the postoperative specimen
	Partial response	Microscopic evidence of residual tumour in the postoperative specimen
	Stable disease	Less than 50% decrease or less than a 25% increase in tumour volume
	Progressive disease	No significant change in tumour mass or more than a 25% increase in tumour volume

*In addition to pathological assessment of the resection specimen, the designation to stable or progressive disease is by re-evaluation of the primary tumour by computed tomography and endoscopy 2 weeks after completion of CRT.

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