Bisphosphonates in breast cancer

Bisphosphonates are osteoclast inhibitors, currently being used in oncology to prevent or delay bone morbidity in cancer. Oral and intravenous formulations of bisphosphonates have been found to be efficacious in preventing skeletal-related events such as bone pain, pathologic fractures, spinal cord compression and hypercalcemia of malignancy, in patients with bone metastatic breast cancer. Bisphosphonates are also used to prevent bone loss associated with anti-estrogen therapy using aromatase inhibitors. In addition to its role in preventing bone resorption, several pre-clinical studies have noted an anti-tumor role as well. Recent research effort has particularly focused on investigating an adjuvant role for bisphosphonates in early breast cancer. Recently, few randomized trials have found a beneficial effect for adjuvant use of the aminobisphosphonate, zoledronate, in older patients who are post-menopausal. This review article will summarize the various clinical studies investigating the role of bisphosphonates in breast cancer.