Table 1. Comparison of irRC, irRECIST and iRECIST criteria.

Criteria	irRC	irRECIST	iRECIST
Definition of measurable disease	Selection of 5 lesions (≥5 × 5 mm) per organ (up to 10 visceral and 5 cutaneous ones)	Selection of maximum 5 (2 per organ) lesions (≥10 mm in diameter; ≥15 mm for nodal lesions)	Selection of maximum 5 (2 per organ) lesions (≥10 mm in diameter; ≥15 mm for nodal lesions)
	New lesions are assessed as the baseline and added to TTB at follow-up	New lesions are included in the sum of target lesions to define the TMTB at follow-up	New lesions are recorded separately on the case report form (but not included in the sum of lesions for target lesions identified at baseline)
Method of measurement	Bidimensional (longest diameter × the longest perpendicular diameter)	Unidimensional (longest diameter)	Unidimensional (longest diameter)
Appearance of new lesions	Added to TTB; do not constitute PD automatically	Added to TMTB; do not constitute PD automatically	Result in iUPD
			iCPD is assigned if at next CSI control additional new lesions appear or an increase in size of new lesions is seen (≥5 mm for sum of new target lesion or any increase in new non-target lesion)
			The appearance of new lesions when none have previously been recorded can also confirm iCPD

irRC, immune-related response criteria; irRECIST, immune-related Response Evaluation Criteria in Solid Tumors; iRECIST, immune RECIST; TTB, total tumor burden; TMTB, total measured tumor burden; PD, progressive disease; iUPD, unconfirmed progressive disease; iCPD, confirmed progressive disease; CSI, cross-sectional imaging.