Restaging rectal cancer following neoadjuvant chemoradiotherapy

Table 1 Recommended tumour response schema for rectal cancer after neoadjuvant chemoradiotherapy

	cCR	ncCR	Poor response
DRE	No palpable tumour material present	Minor mucosal abnormalities	Palpable tumour mass; Cases who do not fulfill the criteria for either a cCR or ncCR
Endoscopy	No residual tumour material or only a small residual erythematous ulcer or scar; Endoscopic biopsy not mandatory to define a cCR, biopsy should not be performed, especially if the DRE, rectoscopy and MRI criteria for a cCR are all fulfilled	Small and smooth regular irregularities including residual ulcer, or small mucosal nodules or minor mucosal abnormalities, with mild persisting erythema of the scar; Endoscopic biopsy not mandatory	Visible macroscopic tumour; Cases who do not fulfill the criteria for either a cCR or ncCR
MRI	Substantial downsizing with no observable residual tumour material, or residual fibrosis only (with limited signal on diffusion weighted imaging), sometimes associated with residual wall thickening owing to oedema, no suspicious lymph nodes	Obvious downstaging with residual fibrosis but heterogeneous or irregular aspects and signal or regression of lymph nodes with no malignant enhancement features, but with a size > 5 mm	Visible macroscopic tumour and/or lack of regression of involved lymph nodes; Cases who do not fulfill the criteria for either a cCR or ncCR

DRE: Digital rectal exam; cCR: Clinical complete response; ncCR: Near clinical complete response; MRI: Magnetic resonance imaging.