Response type | International Union Against Cancer* | WHO¶ |
Complete response | Disappearance of all known disease Lytic lesions should have radiologic evidence of calcification | Complete disappearance of all lesions on plain radiograph or scan for at least four weeks |
Partial response | At least 50% decrease in size of measurable lesions Objective improvement in evaluable or nonmeasurable lesions No new lesions or progressive lesions | Partial decrease in size of lytic lesions, recalcification of lytic lesions, or decreased density of blastic lesions for at least four weeks |
No change (stable disease) | Unchanged, or between 25% increase and 50% decrease in size of measurable lesionsΔ | Because of the slow response of bone lesions, the classification of "no change" should not be applied until at least eight weeks have passed from start of therapy |
Progressive disease | Mixed; some lesions persist while others progress, or new lesions appear Failure; some or all lesions progress and/or new lesions appear No lesions regress | Increase in size of existent lesions or appearance of new lesions |