TABLE II.

Definition of Response

Complete response (CR)	Disappearance of all radiographically discernible lesions with negative CSF cytology
Partial response (PR)	≥50% reduction of all lesions, as measured by the sum of the products of the maximum perpendicular diameters, with negative CSF cytology
Stable disease (SD)	<50% reduction in tumor size, persistently negative or positive CSF cytology
Progressive disease (PD)	>25% increase in tumor size, new lesions, or newly positive CSF cytology

CSF, cerebrospinal fluid.