Adjuvant bisphosphonate therapy for breast cancer patients: Standard of care or future direction?

Bone is the most common site of metastatic spread in breast cancer patients. The use of bisphosphonates (BPs) in women with bone metastases from breast cancer has been shown to reduce the incidence, and delay the onset of, skeletal-related events. Indeed, BPs are now an established standard of care in treating patients with bone metastases. As with many new therapies, once efficacy in the metastatic setting is demonstrated, therapies are tested in the adjuvant setting. There are a number of trials that have tested the hypothesis that BP therapy in women with early breast cancer may not only reduce the development of skeletal metastases but also improve both disease-free and overall survival; recent randomized trials have demonstrated intriguing results regarding the possible anticancer effects of adjuvant BP therapy. Furthermore, interesting signals are filtering through from trials evaluating the role of BPs to prevent cancer-treatment induced bone loss. Many of these trials will be reported in the near future. In this article we review possible subgroups that may benefit from adjuvant treatment with BPs, and ongoing trials that may offer more definitive answers.