Abstract

INTRODUCTION

Objective: Bisphosphonates have been reported to limit tumor formation, in addition to inhibition of bone resorption. We evaluated the effect of intravenous zoledronic acid (ZA) and oral/intravenous ibandronic acid (IA) on progression-free survival (PFS), overall survival (OS), and skeletal-related events (SRE) in breast cancer patients with bone metastases.

METHODS

The retrospective study included patients with metastatic breast cancer who received ZA or IA treatments for at least three months between 2013 and 2018. Menopausal status, presence of visceral metastases, history of skeletal-related events (fracture, radiotherapy, and operation), de novo bone metastasis, and anticancer treatments were recorded. PFS and OS were calculated for each patient.

RESULTS

There were 44 patients in the ZA group as opposed to 22 patients in the IA oral group and 11 patients in the intravenous IA group. Median PFS was 15 months in the ZA group and 25 months in the IA group (p=0.134). Median OS was 81 months in the IA group and 153 months in the ZA group (p=0.088). No significant difference was found between the groups with regard to history of fracture, radiotherapy, and operation (p=0.606, p=0.295 and p=0.747, respectively). The two-year survival rate was 71.5% in the ZA group and 78.3% in the IA group.

DISCUSSION AND CONCLUSION

ZA and IA have similar efficacy in terms of SRE development, PFS and OS. In the selection of treatment for the treatment of bone metastases in metastatic breast cancer, besides evaluating drug efficacy/side effects, treatment compliance and cost should also be considered.