Clinical Trial

Breast Cancer Research and Treatment

, Volume 117, Issue 3, pp 603-609

First online:

Immediate versus delayed zoledronic acid for prevention of bone loss in postmenopausal women with breast cancer starting letrozole after tamoxifen-N03CC

  • Stephanie L. HinesAffiliated withMayo Clinic Jacksonville Email author 
  • , Betty MinceyAffiliated withPrivate Practice
  • , Todor DentchevAffiliated withAltru Health Systems
  • , Jeff A. SloanAffiliated withMayo Clinic Foundation
  • , Edith A. PerezAffiliated withMayo Clinic Jacksonville
  • , David B. JohnsonAffiliated withWichita Community Clinical Oncology Program
  • , Paul L. SchaeferAffiliated withToledo Community Hospital Oncology Program CCOP
  • , Steve AlbertsAffiliated withMayo Clinic Foundation
  • , Heshan LiuAffiliated withMayo Clinic Foundation
    • , Stephen KahanicAffiliated withSiouxland Hematology-Oncology Associates
    • , Miroslaw A. MazurczakAffiliated withSioux Community Cancer Consortium
    • , Daniel A. NikcevichAffiliated withDuluth CCOP
    • , Charles L. LoprinziAffiliated withMayo Clinic Foundation

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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.


Breast cancer Aromatase inhibitor Bone loss Zoledronic acid