Protection of bone in premenopausal women with breast cancer: focus on zoledronic acid

Maintaining bone health is important for patients with breast cancer (BC), the most commonly diagnosed cancer in American women. Indeed, bone loss is common throughout the BC disease continuum. In the metastatic BC setting, patients are likely to develop bone metastases, a painful complication that can lead to potentially debilitating skeletal-related events. Bone health is equally important for patients with early BC. During adjuvant therapy for early BC, the largest challenge to bone health is from accelerated bone mineral density (BMD) loss. Although decreased BMD is well recognized in older, postmenopausal women, it may be underestimated in younger, premenopausal women undergoing endocrine therapy for BC. The rate and extent of cancer therapy-induced bone loss (from chemotherapy or endocrine therapy) are substantially greater than normal decreases in BMD during menopause. Bisphosphonates such as zoledronic acid (ZOL) are antiresorptive agents indicated for the treatment of bone metastases from BC. Clinical trials over the past few years suggest that, although not yet approved for this indication, ZOL can prevent cancer therapy-induced bone loss and improve BMD in premenopausal women receiving adjuvant (endocrine or chemo-) therapy for BC. Furthermore, the benefits of ZOL therapy may go beyond maintaining bone health and include potential anticancer benefits together with favorable tolerability and cost/benefit profiles. This review will focus specifically on the role of ZOL in preserving the bone health of premenopausal women with BC.