Zoledronic acid helps breast cancer patients

A new study suggests zoledronic acid can be an effective adjuvant therapy for premenopausal women with endocrine-responsive early breast cancer. 

The results were presented Saturday at the 33rd Annual San Antonio Breast Cancer Symposium in San Antonio, Texas by Gnant M. and colleagues from the Medical University of Vienna in Wien, Austria.  

The study examined the efficacy of ovarian suppression using goserelin combined with tamoxifen or anastrozole and zoledronic acid in premenopausal women with endocrine-responsive early breast cancer. 

Researchers enlisted 1,803 premenopausal patients with endocrine-responsive early breast cancer who were randomly assigned to goserelin plus tamoxifen or anastrozole plus zoledronic acid for three years.

The results at 48 months and 62 months showed that adjuvant treatment with zoledronic acid significantly improved disease free survival and reduced odds of disease recurrence.

Compared to the control group, those who were on the zoledronic acid reduced their risk of disease free survival events by 36 percent at 48 months of the trial.  The same outcome was observed at 62 months.

The risk of death was reduced by 40 percent at 48 months and 38 percent at 62 months, compared to those on non-zoledronic acid treatment.

Breast cancer patients who received zoledronic acid were also less likely to have recurrence compared to the controls, 29 versus 41 events at 48 months and 44 versus 56 events at 62 months.

The researchers concluded "Comparisons of 48- and 62-month data suggest a possible carry-over of the ZOL anticancer benefit 2 years after treatment completion. Additional analyses will be presented, including disease outcomes during therapy and after treatment, as well as overall survival analyses.

Another study released last March found zoledronic acid helps reduce the spread of breast cancer by reducing chemotherapy related bone loss in women with locally advanced breast cancer.

The study published in The Lancet Oncology showed zoledronic acid together with chemotherapy reduced the likelihood of tumor cells growing in bone marrow and spreading to other organs in the body.

Studies have shown chemotherapy boosts bone turnover, which releases bone derived growth factors which in turn promote tumor growth in women with breast cancer.

Rebecca Aft from Washington University School of Medicine enlisted 120 women undergoing chemotherapy for locally advanced breast cancer to take 4 mg zoledronic acid every three weeks for one year starting with their first dose of chemo or to chemotherapy alone.

Bone marrow samples were taken at 3 months and one year after treatments to examine if tumor cells were present.

About 45.7 percent of patients were found to have tumor cells in their bone marrow at baseline.   

Patients who were on zoledronic acid had fewer tumor cells after three months of treatment compared to the controls.

Of women who started without tumor cells in their bone marrow, 87 percent of those treated with zoledronic acid remained free of tumor cells at three months. This was compared to 60 percent of those who received chemotherapy alone.

Reporting by David Liu and editing by Aimee Keenan-Greene