The Clinical practice guidelines for the management of early breast cancer1define early breast cancer as tumours of not more than five centimetres diameter with either impalpable or palpable, but not fixed, lymph nodes and with no evidence of distant metastases. This guideline is based on evidence on the use of bisphosphonates in women with early breast cancer.
Treatment for women with early breast cancer includes the use of adjuvant therapies, such as chemotherapy and endocrine therapies, to reduce the risk of cancer recurrence or metastasis and improve overall survival. Chemotherapy and some endocrine therapies (aromatase inhibitors and ovarian suppression) are associated with bone mineral density loss, which may increase risk of osteoporosis and fractures.
Bisphosphonates act to reduce the activity of bone-absorbing cells, thus limiting bone mineral density loss, and are standard care in the treatment of osteoporosis.
There are two classes of bisphosphonates, which are administered orally or intravenously depending on the drug:
- nitrogenous (alendronate, ibandronate,^ neridronate, olapadronate, pamidronate, risedronate and zoledronic acid^^) and
- non-nitrogenous (clodronate, etidronate and tiludronate).
The available evidence about the use of bisphosphonates in early breast cancer is limited, especially as the patient populations and treatment regimens vary across trials and there is limited long-term data.
^Ibandronate is also called ibandronic acid.
^^Zoledronic acid is also called zoledronate or zolendronate.