Osseous metastases in breast cancer: Radiographic monitoring of therapeutic response

Background: Standard radiographs are primary means of evaluation of therapy-induced changes of the skeletal structure in patients with breast cancer metastatic to the bone, but objective quantitation has been difficult to standardize. Materials and Methods: Serial radiographs of therapy-induced changes in the structure of bone metastases secondary to breast cancer were analyzed in 274 patients over a period of 10 years and roentgenologic signs of tumor response evaluated with regard to a defined principal metastasis. Results: Indicators of regression were recalcification/reossification of primary osteolysis (11.6%), the formation of marginal sclerosis around the defect (13.5%) and lack of progression over a period of up to at least 12 months (10.5%). Reduction of sclerosis or structural loosening in primary osteosclerotic metastases (2.5%) may also be evidence of regression. Recurrence or progression of tumor was manifested by new metastases and/or increase in lesion size (56.9%) as well as development of lytic areas in primarily sclerotic or mixed metastases (2.5%). One hundred and one out of 157 patients with initially sclerotic or mixed metastases stayed stable or showed a response which lasted 12 months or longer. The duration of response in osteolytic lesions was less favourable. Irradiation and complex treatment (chemotherapy or hormonal therapy plus irradiation) was most often associated with a favourable objective response, 75%, which in 8 cases reflected nonprogression of disease, recalcification of primary osteolysis in 11 cases, the formation of marginal sclerosis around the defect in 8 lesions and disappearance of metastases in 1 case. Conclusion: Standard radiographs are useful in the serial evaluation of the effectiveness of therapy for osseous metastases in that anatomic quantitation of lesions as well as the dynamic evolution of lytic lesions to blastic healing may be observed.