Bone metastases in breast cancer

Patients with advanced breast cancer who develop bone metastases suffer from long-term skeletal morbidity. Complications of bone metastases include pain, pathologic fractures, and spinal cord compression, which have a significant impact on the quality of life of patients. Treatment options for patients with bone metastases include surgery, radiation, and analgesics to reduce bone pain and to prevent or repair fractures. Intravenous bisphosphonates can delay the onset of bone metastasis and reduce the percentage of patients who experience skeletal complications of bone metastasis, thus reducing skeletal morbidity. For the past 6 years, pamidronate disodium (90 mg administered by 2-hour intravenous infusion) has been the treatment of choice for the prevention of skeletal complications of bone metastases in patients with breast cancer. However, a more potent bisphosphonate, zoledronic acid (4 mg administered by 15-minute intravenous infusion), was approved for use and has improved efficacy in patients with bone metastases. Because of the increased efficacy and more convenient infusion time, zoledronic acid may become the new standard of care for the treatment and prevention of skeletal complications secondary to bone metastases in patients with breast cancer. Phase III clinical trials have shown that patients with an existing skeletal complication are more likely to develop subsequent complications compared with patients who have not experienced a complication. Therefore, zoledronic acid therapy should be initiated when the patient is diagnosed with bone metastasis.