New approaches for precise response evaluation in hepatocellular carcinoma

Table 1 Summary of response criteria

	WHO	RECIST 1.1	EASL	mRECIST
Complete response (CR)	Disappearance of all lesions	Disappearance of all lesions and pathologic lymph nodes	Disappearance of intratumoral areterial enhancement	Disappearance of all lesions and pathologic lymph nodes
Partial response (PR)	≥ 50% decrease in the sum of the area (longest diameters multiplied by longest perpendicular diameters)	≥ 30% decrease in the sum of the longest diameters	≥ 50% decrease in the sum of the arterial enhancing areas (longest diameters multiplied by longest perpendicular diameters)	At least a 30% decrease in the sum of diameters viable (enhancing) target lesions, taking as reference the baseline sum of the target lesions
Stable disease (SD)	Neither PR nor PD	Neither PR nor PD	Neither PR nor PD	Neither PR nor PD
Progressive disease (PD)	≥ 25% increase in the sum of the area	≥ 20% increase in the sum of the longest diameters and ≥ 5 mm absolute increase in the sum of the longest diameters	≥ 25% increase in the size of the arterial enhancing areas or development of a new lesions	≥ 20% increase in the sum of diameters of viable target lesions recorded since treatment started or development of new lesions

WHO: World Health Organization; EASL: European Association for the Study of Liver; mRECIST: Modified Response Evaluation Criteria in Solid Tumors.

Table 2 Comparison of European Organization for Research and Treatment of Cancer and Positron Emission Tomography Response Criteria in Solid Tumors 1.1

	EORTC	PERCIST
CMR	Complete resolution of 18F-FDG uptake within the tumor volume so that it is indistinguishable from surrounding normal tissue	Complete resolution of 18F-FDG uptake within measurable target lesion so that the liver activity was less than the mean and indistinguishable from surrounding background blood-pool levels plus disappearance of all other lesions to background blood pool levels and appearance of no new 18F-FDG-avid lesions
PMR	Minimum 15%-25% reduction in tumor 18F-FDG SUV after 1 chemotherapy cycle and > 25% reduction after ≥ 1 treatment cycle; reduction in extent of tumor 18F-FDG uptake not required	≥ 30% relative and ≥ 0.8 SUL unit absolute reduction in target measurable tumor 18F-FDG SUL peak and no increase > 30% in SUL or size (per RECIST) of target or nontarget lesions or appearance of new lesions; reduction in extent of tumor 18F-FDG uptake not required ≥ 30% decrease in the sum of the longest diameters
SMD	< 25% increase or < 15% decrease in tumor 18F-FDG SUV and no visible increase in extent of 18F-FDG tumor uptake (> 20% in the longest dimension)	Not CMR, PMR, nor PMD
PMD	> 25% increase in 18F-FDG tumor SUV within the tumor region defined on the baseline examination or visible increase in the extent of 18F-FDG tumor uptake (> 20% in the longest dimension) or appearance of new 18F-FDG uptake in metastatic lesions	> 30% increase in 18F-FDG SUL peak, with > 0.8 SUL unit increase in tumor SUV peak from baseline scan in pattern typical of tumor and not of infection/treatment effect or visible increase in extent of 18F-FDG tumor uptake (75% in total lesion glycolysis volume with no decline in SUL) or new 18F-FDG-avid lesions typical of cancer and not related to treatment effect or infection

CMR: Complete metabolic response; PMR: Partial metabolic response; SMD: Stable metabolic disease; PMD: Progressive metabolic disease; EORTC: European Organization for Research and Treatment of Cancer; PERCIST: Positron Emission Tomography Response Criteria in Solid Tumors; FDG: Fluorodeoxyglucose; SUV: Standardized uptake values.