Table 1.
Category | PERCIST | EORTC 1999 | RECIST 1.1 | irRC |
Target lesions | The hottest single tumor lesion (SUL peak) at baseline 18F-FDG PET | The most 18F-FDG-avid lesions (SUV BSA). Number of lesions not specified | Maximum, 5 | Maximum, 15 lesions |
New lesion | Results in progressive disease at first appearance | Results in progressive disease at first appearance | Results in progressive disease at first appearance | Up to 10 new visceral and 5 cutaneous lesions may be added to the sum of the products of the two largest perpendicular diameters of all index lesions at any time point |
Complete response | CMR: Complete resolution of 18F-FDG uptake within the target lesion (< mean liver activity and indistinguishable from background/blood pool and no new 18F-FDG-avid lesions) | CMR: Complete absence of 18F-FDG uptake | Disappearance of all target and nontarget lesions Nodes must regress to < 10 mm short axis No new lesions Confirmation required | |
Partial response | PMR: A reduction of a minimum of 30% in the target tumor 18F- FDG SUL peak | PMR: A decrease in SUV > 25% | ≥ 30% decrease in tumor burden compared to baseline Confirmation required | ≥ 50% decrease in tumor burden compared with baseline1 Confirmation required |
Progressive disease | PMD: A 30% increase in 18F-FDG SUL peak or advent of new 18F-FDG-avid lesions | PMD: An increase in SUV > 25% or appearance of new lesions | ≥ 20% + 5 mm absolute increase in tumor burden compared with nadir Appearance of new lesions or progression of nontarget lesions | ≥ 25% increase in tumor burden compared with baseline, nadir or reset baseline1 New lesions added to tumor burden Confirmation required |
Stable disease | SMD: Disease other than CMR, PMR or PMD | SMD: Increase in SUV by < 25% or decrease in SUV by < 15% | Neither partial response nor progressive disease |
If an increase in tumor burden is observed at the first scheduled assessment, the baseline is reset to the value observed at the first assessment. PERCIST: PET Response Criteria in Solid Tumors; EORTC: European Organization for Research and Treatment of Cancer; RECIST: Response Evaluation Criteria in Solid Tumors; irRC: Immune related Response Criteria; CMR: Complete metabolic response; PMR: Partial metabolic response; PMD: Progressive metabolic disease; SMD: Stable metabolic disease; SUL: SUV normalized to lean body mass; SUV BSA: SUV normalized for body surface area; SUV: Standardized uptake value.