Postmenopausal women with breast cancer (BC) are at increased risk for bone loss. Bisphosphonates improve bone mineral density (BMD) in normal postmenopausal women. The purpose of this study was to determine if immediate treatment with zoledronic acid preserves BMD in postmenopausal women with BC starting letrozole after tamoxifen. Postmenopausal women with BC completing tamoxifen were treated with daily letrozole 2.5 mg/vitamin D 400 I.U., calcium 500 mg twice daily and were randomized to upfront or delayed zoledronic acid 4 mg every 6 months. Patients in the delayed arm were only given zoledronic acid if they developed a post-baseline BMD T score <−2.0 or had a fracture. The primary endpoint was the mean percent change in lumbar spine (LS) BMD at 1 year. About 558 women enrolled; 395 provided 1 year BMD data. The upfront arm experienced a mean change of +3.66% in LS BMD versus -1.66% for the delayed group (P < 0.001). Changes at the femoral neck/total hip were also greater for the upfront versus delayed arms (P < 0.001; P < 0.001) with differences persisting at 2 years. Patients in the delayed arm were more likely to experience a clinically meaningful 5% loss of BMD at all sites versus the upfront zoledronate group. Patients in the upfront arm were slightly more likely to report limb edema, fatigue, fever, nausea and jaw osteonecrosis(1%). Upfront zoledronic acid prevents bone loss in postmenopausal women with BC starting letrozole after tamoxifen.

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A B S T R A C T PurposeRisedronate prevents bone loss in postmenopausal women. The purpose of this study was to determine whether risedronate prevents bone loss in premenopausal women undergoing chemotherapy for breast cancer. Patients and MethodsPremenopausal women undergoing chemotherapy for breast cancer were treated with oral calcium 600 mg and vitamin D 400 U daily and randomly assigned to receive oral risedronate 35 mg weekly or placebo, with all these therapies beginning within a month of the start of chemotherapy. Most chemotherapy regimens included anthracyclines, taxanes, or cyclophosphamide. Bone mineral density (BMD) was measured at baseline and 1 year. The primary end point was the change in lumbar spine (LS) BMD from baseline to 1 year. ResultsA total of 216 women enrolled; 170 women provided BMD data at 1 year. There was no difference in the mean change or percent change in LS BMD between groups, with a loss of 4.3% in the risedronate arm and 5.4% for placebo at 1 year (P ϭ .18). Loss of BMD at the femoral neck and total hip were also similar between treatment groups. Risedronate was well tolerated, with no significant differences in adverse events compared with placebo, except that arthralgias and chest pain were worse in those receiving the placebos. ConclusionRisedronate did not prevent bone loss in premenopausal women undergoing adjuvant chemotherapy for breast cancer.