This is a two arm, double-blind randomized study looking at the effect of zoledronate, a bisphosphonate, on the bone mineral density (BMD) of postmenopausal women with breast cancer.

This is a two arm, double-blind randomized study looking at the effect of zoledronate, a bisphosphonate, on the bone mineral density (BMD) of postmenopausal women with breast cancer. An approved bisphosphonate, alendronate, is of benefit in patients with osteoporosis, however, this agent has a roughly 30% incidence of gastrointestinal symptoms and up to 50% of patients may take the drug improperly, compromising absorption and potentially efficacy. Zoledronate is a heterocyclic imidazole third generation bisphosphonate, which is administered intravenously (IV) and has little toxicity. Zoledronate is more potent than alendronate, and because of its route of administration it does not have the problems of poor oral bioavailability and non-compliance.

Inclusion Criteria:

• Postmenopausal women, Stage III or axillary node positive
• Currently disease free of breast cancer and other invasive malignancies at the time of registration
• No concurrent use of bisphosphonates

Exclusion Criteria:

• Metastatic disease

Postmenopausal women with stage II/III breast cancer diagnosed up to 5 years previous.

Adverse event data was collected for up to 48 weeks.

Toxicity evaluation including telephone assessment occurred at 1 week after the start of each cycle.

Toxicities for the Zoledronate arm were assessed at 9 time points, and toxicities for the Observation arm were assessed at 2 time points.