Table 2.

Summary of comparison of RECIST 1.1, irRC, irRECIST, iRECIST, PERCIST, and imPERCIST criteria for immunotherapy.

RECIST 1.1 (2009)	CR	PR	SD	PD
	Complete disappearance of target and nontarget lesions	⩾30% decrease from baseline	Neither PD, PR nor CR	⩾ 20% increase in the nadir of the sum of target lesions, with a minimum of 5 mm, or new lesions
irRC (2009)	irCR	irPR	irSD	irPD
	Complete disappearance of target lesions and no new nonmeasurable lesions	Disappearance of target lesions and stable or unequivocal progression of nontarget lesions or ⩾50% decrease in target lesion and absent, stable, or unequivocal progression of nontarget lesions	<50% decrease or <25% increase of target lesions and absent, stable, or unequivocal progression of nontarget lesions	>25% increase of target lesions and any change of nontarget lesions
irRECIST (2013)	Complete disappearance of target and nontarget lesions	⩾30% decrease from baseline	Neither irPD, irPR nor irCR	⩾20% increase in total measured tumor burden compared with nadir of progression of nontarget lesions or new lesions Confirmation of progression recommended minimum 4 weeks after the first irPD assessment
iRECIST (2020)	iCR	iPR	iSD	iUPD	iCPD
	Complete disappearance of target and nontarget lesions. All lymph nodes must be nonpathological in size (<10 mm in SAD)	⩾30% decrease of target lesions compared with the baseline, or in the case of complete remission of the TL, when one or more non-TL can still be distinguished	The criteria of iCR or iPR are not met and no tumor progression is present	Further progress of the target sum (⩾5 mm), or any further progress of the non-TL, and/or progress of the new measurable and not measurable lesions either in number or in size (sum ⩾ 5 mm)	An increase in the sum of all TL by at least ⩾20% (but at least ⩾ 5 mm) compared with the time point with the lowest TL sum (Nadir), or an unequivocal progression of non-TL, or by the occurrence of new measurable and/or nonmeasurable tumor lesions Need to be confirmed 4–8 weeks later; if progression is followed by tumor shrinkage, the bar is reset
PERCIST (2009)	CMR	PMR	SMD	PMD
	Complete disappearance of all metabolically active tumors	⩾30% decrease of SULpeak in target lesions, and absolute drop in SUL by at least 0.8 SUL units	Neither PMD, PMR nor CMR	⩾30% increase of SULpeak or the appearance of any new metabolically active lesions
ImPERCIST (2019)	CMR	PMR	SMD	UPMD	CPMD
	Disappearance of all metabolically active tumors	⩾30% decrease of SULpeak in target lesions, and absolute drop in SUL by at least 0.8 SUL units	Neither PMD, PMR nor CMR	⩾30% increase of SULpeak or the appearance of any new metabolically active lesions	⩾30% increase of SULpeak or the appearance of any new metabolically active lesions Need to be confirmed by a second PET at 4–8 weeks later; if progression is followed by PMR or SMD, the bar is reset

CMR, complete metabolic response; CPMD, confirmed progressive metabolic disease; CR, complete remission; iCPD, immune confirmed progressive disease; iCR, immune complete remission; imPERCIST, immunotherapy-modified PERCIST; iPR, immune partial remission; irCPD, immune-related confirmed progressive disease; irCR, immune-related complete response; iRECIST, immuno-RECIST; irPD, immune-related progressive disease; irPR, immune-related partial response; irRC, immune-related response criteria; irRECIST, immune-related RECIST; irSD, immune-related stable disease; iSD, immune stable disease; iUPD, immune unconfirmed progressive disease; PD, progressive disease; PERCIST, PET response criteria in solid tumors; PET, positron emission tomography; PMD, progressive metabolic disease; PMR, partial metabolic response; PR, partial remission; RECIST, response evaluation criteria in solid tumors; SD, stable disease; SAD, short axis diameter; SMD, stable metabolic disease; SUL, standardized uptake value normalized by lean body mass; TL, target lesion; UPMD, unconfirmed progressive metabolic disease.