Bisphosphonates in breast cancer: teaching an old dog new tricks

Bisphosphonates are potent inhibitors of bone resorption that reduce the risk of skeletal complications and prevent treatment-induced bone loss. However, recent data suggest that bisphosphonate use in breast cancer may provide more than just supportive care and modify the course of the disease by disrupting the metastatic process.

Research in the metastatic setting is focused on refining treatment, using bone markers to identify high-risk patients and define optimal schedules, potentially leading to personalized therapy. In the prevention of cancer treatment-induced bone loss (CTIBL), a large number of studies have demonstrated the efficacy of oral and intravenous bisphosphonates and recent guidelines have defined management strategies for CTIBL. Preclinical studies have reported direct antitumour effects of bisphosphonates, particularly in combination with chemotherapy. In the clinical setting the antitumour effect is less clear, but recent data suggest that zoledronic acid may modify the course of the disease and reduce disease recurrence.

Bisphosphonates are comprehensively established in the treatment of metastatic bone disease and significantly reduce skeletal morbidity. Their role in the prevention of cancer treatment-induced bone disease is also defined. The potential antitumour and disease-modifying role of adjuvant bisphosphonates holds promise but results from ongoing studies must be awaited before this becomes standard practice.