Abstract:

Objective To compare the clinical efficacy and adverse effects of anastrozole therapy involving either zoledronic acid or pamidronate disodium for reducing skeletal complications in patients with postmenopausal breast cancer involving bone metastases. Methods This study involved 51 patients diagnosed with postmenopausal breast cancer with bone metastases based on pathology and imaging between January 2010 and June 2014. Patients were randomly allocated into a control group that received anastrozole and pamidronate disodium（n=27） or a group that received anastrozole and zoledronic acid （n=24）. Drugs were administered on a 28-day cycle as follows：anastrozole，1 mg，qd，po； zoledronic acid，4 mg， ivgtt；pamidronate disodium，60 mg，ivgtt. Survival time based on skeletal-related events（SREs） and overall survival were evaluated strictly. Bone pain，bone metastasis remission and adverse reactions were also recorded. Results On day 14 of treatment， the total effective rate of pain relief was significantly higher in the anastrozole and zoledronic acid group（87.5%） than in the control group （66.7%，P<0.05）. On day 56，the respective rates were similar （91.7% vs 77.8%，P>0.05）. Anastrozole and zoledronic acid treatment led to significantly greater bone metastasis remission （P<0.05），longer median survival time without SREs （22.4  vs 17.4 months，P<0.05） and longer median overall survival time（35.1 vs 25.8 months， P<0.05）. Frequent adverse effects included fever as well as muscle and bone pain；these effects　were relieved after symptomatic treatment. Conclusion Using zoledronic acid in combination with anastrozole  shows good efficacy and tolerable toxicity in patients with postmenopausal breast cancer involving bone metastasis. This therapy merits further clinical studies.

Key words: Breast neoplasm, Zoledronic acid, Pamidronate disodium, Anastrozole, Bone metastasis, Efficacy, Safety