Table 3. Comparison between WHO, RECIST version 1.1, and irRC criteria.
| RECIST | WHO | irRC | |
|---|---|---|---|
| New measurable lesion (i.e., ≥5×5 mm) | Always represent PD | Always represent PD | Incorporated into tumour burden |
| New non-measurable lesion (i.e., <5×5 mm) | Always represent PD | Always represent PD | Do not define progression (but preclude irRC) |
| Non-index lesions | Changes contribute to defining BOR of CR, PR, SD, and PD | Changes contribute to defining BOR of CR, PR, SD, and PD | Contribute to defining irRC (complete disappearance required) |
| CR | Disappearance of all lesions in one observation in randomized studies; confirmation is needed for non-randomize d studies according to study protocol | Disappearance of all lesions in two consecutive observations not less than 4 weeks apart | Disappearance of all lesions in two consecutive observations not less than 4 weeks apart |
| PR | At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, in the absence of new lesions or unequivocal progression of non-index lesions | A ≥50% decrease in SPD of all index lesions compared with baseline in observations, at least 4 weeks apart, in the absence of new lesions or unequivocal progression of non-index lesions | A ≥50% decrease in tumour burden compared with baseline in two observations at least 4 weeks apart |
| SD | Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum diameters, in the absence of new lesions or unequivocal progression of non-index lesions | A 50% decrease in SPD compared with baseline cannot be established, nor 25% increase compared with nadir, in absence of new lesions or unequivocal progression of non-index lesions | A 50% decrease in tumour burden compared with baseline cannot be established, nor 25% increase compared with nadir |
| PD | At least 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study; the sum must also demonstrate an absolute increase of at least 5 mm; the appearance of one or more new lesions is also considered progression | A t le as t 25% incr e ase in S P D compare d with nadir and/or unequivocal progression of non-index lesions and/or appearance of new lesions (at any single time point) | At least 25% increase in tumour burden compared with nadir (at any single time point) in two consecutive observations at least 4 weeks apart |
Adopted from Ades F and Yamaguchi N. Ecancermedicalscience 2015;9:604, according to the Creative Commons license31.
WHO: World Health Organisation; RECIST: Response Evaluation Criteria In Solid Tumor; irRC: immune-related response criteria; PD: progressive disease; BOR: best overall response; CR: complete response; PR: partial response; SD: stable disease; SPD: sum of the product of the greatest diameters.