Objective response rate assessment in oncology: Current situation and future expectations

Table 1 The World Health Organization, Response Evaluation Criteria in Solid Tumors version 1.0 and Response Evaluation Criteria in Solid Tumors version 1.1 criteria¹

	WHO	RECIST v1.0	RECIST v1.1
Method	Sum of products of two longest diameters in perpendicular dimensions (bidimensional; surface area)	Sum of longest diameters of target lesions (unidimensional)	Sum of longest diameters of non-nodal target lesions and short axis of nodal target lesions (unidimensional)
No. of measured lesion	All lesions	Target lesions: maximum 5 per organ, 10 in total	Target lesions: Maximum 2 per organ, 5 in total
Response
CR	Disappearance of all known disease, confirmed at 4 wk2	Disappearance of all known disease, confirmed at 4 wk	Disappearance of all known disease, confirmed at 4 wk, lymph nodes must be < 10 mm short axis
PR	≥ 50% decrease from baseline, confirmed at 4 wk	≥ 30% decrease from baseline, confirmed at 4 wk	≥ 30% decrease from baseline, confirmed at 4 wk
SD	Neither PR nor PD criteria met	Neither PR nor PD criteria met	Neither PR nor PD criteria met
PD	≥ 25% increase, no CR, PR, or SD, new lesion (s), ≥ 25% increase in 1 lesion	≥ 20% increase over smallest sum observed, no CR, PR, or SD, new lesion(s)	≥ 20% increase over smallest sum observed, no CR, PR, or SD, new lesion(s)3. The sum must also demonstrate an absolute increase of at least 5 mm

¹Modified from Choi et al[12], and extended with adding Response Evaluation Criteria in Solid Tumors version 1.1;

²Minimum interval between baseline assessment and first response evaluation;

³On detection of new lesions, fluorodeoxyglucose-positron emission tomography scan is included. CR: Complete response; PR: Partial response; SD: Stable disease; PD: Progressive disease; WHO: World Health Organization; RECIST: Response Evaluation Criteria in Solid Tumors.