WHO Criteria for Response of Metastatic Bone Lesions to Therapy

The World Health Organization (WHO) published criteria for describing the response of metastatic bone cancer to therapy.

Imaging Study (X-Ray or Scan)	Response
complete disappearance of all lesions for >= 4 weeks	complete
partial decrease in size of lytic lesions for >= 4 weeks	partial
recalcification of lytic lesions for >= 4 weeks	partial
decreased density for blastic lesions for >= 4 weeks	partial
no change in size, number or appearance of bone lesions for >= 8 weeks	no change (stable disease)
increase in size of lesions	progressive
appearance of new lesions	progressive

where:

• The patient should be evaluated for several weeks after therapy prior to classification because of the relative slow response of bone lesions.

• Caution should be used in interpreting lesions with compression and fracture.

To read more or access our algorithms and calculators, please log in or register.