Clinical efficacy of bisphosphonate therapy for bone metastasis from breast cancer

Bisphosphonates inhibit osteoclastic bone resorption and are being used as treatment for bone metastases from breast cancer. Intravenous bisphosphonate therapy can significantly reduce skeletal related events (SREs) when administered concurrently with chemotherapy or endocrine therapy. In addition, intravenous bisphosphonate monotherapy is also able to alleviate cancer induced bone pain, and to improve bone metastases in some patients. Oral bisphosphonates are not routinely used for the treatment of bone metastases due to their low bioavailability. However, minodronate, a bisphosphonate 100-fold more potent than pamidronate, is now in phase II clinical studies in Japan, and may alter the role of oral bisphosphonates in the treatment of bone metastasis from breast cancer. The ASCO guidelines recommend that patients with osteolytic bone metastases be treated not with bisphosphonate monotherapy, but with concurrent bisphosphonate and systemic therapy. In addition, it is also recommended that current standards of care for cancer pain, analgesics and radiotherapy, should not be replaced with bisphosphonate therapy.