Zoledronic acid prevents bone loss in premenopausal women with early breast cancer undergoing adjuvant chemotherapy: a phase III trial of the Korean Cancer Study Group (KCSG-BR06-01).

To determine whether zoledronic acid (ZA) can prevent bone loss in premenopausal women undergoing adjuvant chemotherapy for breast cancer. In this randomized, open-label, phase III multicenter trial, premenopausal women >40 years were randomly assigned to ZA treatment (4 mg IV, every 6 months) or observation after surgery. All patients were treated with four cycles of AC followed by four cycles of taxane. Between March 2007 and May 2008, we assessed a total of 112 premenopausal women, all of whom developed amenorrhea at 1 year after chemotherapy. The mean percent change of BMD in the lumbar spine (LS) was -1.1% in the ZA group versus -7.5% in observation group at 12 months. Differences in percent change of BMD from baseline between the two groups were 6.4% for the LS, and 3.6% for the femoral neck. The mean levels of bone turnover at 12 months were significantly lower in the ZA group. ZA was generally well tolerated. Infusion of ZA 4 mg every 6 months effectively prevented bone loss within the first year in premenopausal women receiving adjuvant chemotherapy for early breast cancer. Regular BMD measurements and early bisphosphonate therapy should be considered in these patients.