Comparison of response criteria for different measurement approaches

	RECIST (1D)³	Macdonald (2D)⁴	Volumetric Extrapolated from RECIST^*^,^†	Volumetric Extrapolated from Macdonald^*^,^‡
CR	Resolution of all enhancing tumor; confirm at 4 weeks	Resolution of all enhancing tumor; confirm at 4 weeks	Resolution of all enhancing tumor; confirm at 4 weeks	Resolution of all enhancing tumor; confirm at 4 weeks
PR^§	≥30% decrease in sum of maximal diameters; confirm at 4 weeks	≥50% decrease in product of 2 orthogonal diameters; confirm at 4 weeks	≥66% decrease in volume; confirm at 4 weeks	≥65% decrease in volume; confirm at 4 weeks
SD	All others	All others	All others	All others
PD^‖	≥20% increase in sum of maximal diameters; confirm at 4 weeks	≥25% increase in product of orthogonal diameters; confirm at 4 weeks	≥73% increase in volume; confirm at 4 weeks	≥40% increase in volume; confirm at 4 weeks
Comment	Single longest diameter of the lesion or sum of longest diameters of multiple measurable lesions (see text)	Product of orthogonal diameters on section with largest tumor area; sum of products if multiple measurable lesions	Computer-assisted volumetrics using a perimeter methodology; sum of volumes if multiple measurable lesions	Use of these values would be equally stringent for PR comparing RECIST and Macdonald criteria but would be more stringent for PD compared with RECIST but comparable with Macdonald criteria

Note:—CR indicates complete response; PR, partial response; SD, stable disease; PD, progressive disease.
* “Extrapolated” refers to converting single diameter or orthogonal diameter measurements to a volume assuming a spheric lesion using the formula V = 4/3πr³.
† Volume versus 1D (ie, cube of linear RECIST criteria).
‡ Volume versus 2D.
§ Percentage change from baseline (see text).
‖ Percentage change from nadir (see text).