response (cancer treatment)

For reporting results of cancer treatment the following definitions (WHO) of objective response are used (separately!): (I) measurable disease: complete response (CR) = disappearance of all known disease, determined by 2 observations not less than 4 weeks apart; partial r. (PR)= 50% or more decrease in total tumour size of the lesions which have been measured to determine the effect of therapy by 2 observations not less than 4 weeks apart (there can be no appearance of new lesions or progression of any lesion); no change (NC)= 50% decrease in total tumour size cannot be established nor has a 25% increase in the size of one or more measurable lesions been demonstrated; progressive disease (PD)= 25% or more increase in the size of one or more measurable lesions, or the appearance of new lesions; (II) unmeasurable disease: complete r. (CR) = complete disappearance of all known disease for at least 4 weeks; partial r. (PR) = estimated decrease in tumour size of 50% or more for at least 4 weeks; no change (NC) = no significant change for at least 4 weeks; this includes stable disease, estimated decrease of less than 50%, and lesions with estimated increase of less than 25%; progressive disease (PD) = appearance of any new lesion not previously identified or estimated increase of 25% or more in existent lesions