Osseous metastases of breast cancer. Clinical, biochemical, radiographic, and scintigraphic evaluation of response to therapy.

Serial bone scans and radiographs were assessed in 50 patients with breast cancer metastatic to bone treated with combination chemotherapy. In 34 patients evaluable nonosseous metastases were present in addition to bone lesions. Clinical and biochemical changes also were assessed serially, independent of skeletal disease. Pretherapy bone scans were more sensitive but less specific than radiographs for detection of osseous metastasis. Response to therapy in nonosseous metastasis correlated well with radiographic improvement of bone lesions (91%), but less well with changes in bone scans (57%). There was concordance between clinical and radiographic findings, suggesting progression of metastatic disease, in 81% of patients and between scan and clinical findings in 72% of them. Changes in carcinoembryonic antigen levels closely reflected clinical and radiographic changes. Serial bone radiographs are the most useful method of determining response to therapy in breast cancer metastatic to bone. The addition of scintigraphs and carcinoembryonic antigen measurements results in a highly sensitive and accurate method of response evaluation.