304P - Assessment of bisphosphonates use as adjuvant therapy in breast cancer

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Breast Cancer, Early Stage
Supportive Care
Presenter Fouad M. Abu-Taleb
Citation Annals of Oncology (2014) 25 (suppl_4): iv85-iv109. 10.1093/annonc/mdu327
Authors F.M. Abu-Taleb1, H.M. El-Zawahry2, Z.K. Zekri2, R.M.M. Gaafar2, N.M.A. Al Lahloubi2, N. Zakhari3, O. Elfarargy1, A. Abdel Raheem Alnagar1
  • 1Medical Oncology, Zagazig University Hospitals, Faculty of Medicine, 44519 - Sharkia/EG
  • 2Medical Oncology, National Cancer Institute Kasr El AiniCairo University, EG-11796 - Cairo/EG
  • 3Biochemistry And Tumour Biology, National Cancer Institute Kasr El AiniCairo University, EG-11796 - Cairo/EG

Abstract

Aim

Breast cancer is the most frequently diagnosed cancer in females. It is the leading cause of cancer deaths in females ranking as the first malignancy affecting females in Egypt and accounts for 30% of female cancers, 39.5% are postmenopausal. Adjuvant aromatase inhibitors (AI) alone or sequentially after tamoxifen increases disease free survival in postmenopausal women compared with tamoxifen alone, but at the expense of increased bone loss. Bisphosphonates including zoledronic acid have been shown to reduce cancer treatment-induced bone loss.

Methods

This is a prospective randomized phase III study where 120 postmenopausal females with non-metastatic hormone-receptor-positive breast cancer completed initial therapy with baseline ECOG performance status ≤ 2, baseline lumbar spine (LS) and total hip (TH) T-score≥ -2 were included. Patients received letrozole 2.5 mg orally daily till disease progression with or without zoledronic acid 4 mg IV over 15 minutes every 6 months for 2 years . Evaluation of bone health was done by measuring bone mineral density (BMD) using Dual energy X-ray absorptiometry (DEXA) at base line, at 12 months and 24 months, also N-telopeptide Ntx was measured at baseline and at 12 months. Toxicity was analyzed according to NCI-CTC, with the primary end point to evaluate changes in bone health by measuring BMD, changes in the bone turnover marker urinary (Ntx) at 12 months, and evaluating disease-free survival (DFS).

Results

Patients' clinicopathological characteristics were evenly matched, at 12 months evaluation the zoledronic acid arm had increased BMD in LS&TH with mean% change (+2.7%) and (+2.1%) compared with (-6.84%) and (-4.24%) in the other arm (p< 0.001 for both), at 24 months the zoledronic acid arm experienced increased BMD in LS&TH with mean% change from that of base line (+5.42%) and (+3.43%)compared with base line compared to (-8.59%) and (-5.72%) in the other arm (p < 0.001 for both). As for Ntx the mean % decreased by 6.59% in the zoledronic acid arm compared with 26.35% increase in the other arm (p< 0.001). Regarding DFS there was no difference at 37 months follow-up (p = 0.714),with no significant difference between both arms regarding toxicity.

Conclusions

Adding zoledronic acid to adjuvant letrozole in postmeopausal breast cancer patients improves bone health as shown by BMD and Ntx.

Disclosure

All authors have declared no conflicts of interest.