Table 5.

MacDonald criteria for assessment of brain tumor treatment response *.

Types of Response	Definition
Complete Response (CR)	Complete disappearance of all enhancing tumors on consecutive CT or MRI scans at least 1 month apart, off steroids, and neurologically stable or improved.
Partial Response (PR)	≥50% reduction in size of enhancing tumor on consecutive CT or MRI scans at least 1 month apart, steroids stable or reduced, and neurologically stable or improved
Progressive Disease (PD)	>25% increase in size of enhancing tumor or any new tumor on CT or MRI scans, or neurologically worse, and steroids stable or increased
Stable Disease (SD)	Imaging features do not qualify for CR, PR, or PD and neurologically stable

* Measurements are obtained at the tumor’s largest cross-sectional area.