Table 2.

Response assessment of target and non-target lesions (Lin et al., 2015).

Target lesions
Complete response
Disappearance of CNS target lesion(s) sustained for at least 4 weeks; with no new lesions, no use of corticosteroids and patient is stable or improved clinically.
Partial response
At least a 30% decrease in the sum longest diameter of CNS target lesion(s), taking as reference the baseline sum longest diameter sustained for at least 4 weeks; no new lesions; stable to decreased corticosteroid dose; stable or improved clinically.
Progressive disease
At least a 20% increase in the sum longest diameter of CNS target lesion(s), taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study). In addition to the relative increase of 20%, at least one lesion must increase by an absolute value of 5 mm or more to be considered progression.
Stable disease
Neither sufficient shrinkage to qualify for partial response nor sufficient increase to qualify for progressive disease, taking as reference the smallest sum longest diameter while on study.
Non-target lesions
Non-target lesions should be assessed qualitatively at each of the time points specified in the protocol.
Complete response
Requires all of the following: disappearance of all enhancing CNS non-target lesions, no new CNS lesions.
Non-complete response or non-progressive disease
Persistence of one or more non-target CNS lesion or lesions.
Progressive disease
Any of the following: unequivocal progression of existing enhancing non-target CNS lesions, new lesion(s) (except while on immunotherapy-based treatment), or unequivocal progression of existing tumor-related non-enhancing (T2/FLAIR) CNS lesions. In the case of immunotherapy-based treatment, new lesions alone may not constitute progressive disease.