Bone Loss Drug Reduces Early-Stage Breast Cancer Recurrence Risk

The study: Researchers looked at whether zoledronic acid (Zometa) lowers the risk of breast cancer recurrence (cancer that comes back after treatment) for premenopausal women with early-stage breast cancer. Zoledronic acid is a drug called a bisphosphonate that is used to reduce bone loss caused by cancer treatment. The women were treated with surgery, ovarian suppression (drugs that stop the production of hormones by the ovaries), and hormone therapy. Hormone therapy is the used to treat breast cancer that is hormone-receptor positive (uses estrogen or progesterone to grow) and includes tamoxifen (Nolvadex) and anastrozole (Arimidex).

In this study, 1,803 women who were undergoing drug-induced ovarian suppression were divided into four treatment groups: tamoxifen only, anastrozole only, tamoxifen and zoledronic acid, or anastrozole and zoledronic acid. Tamoxifen is the standard treatment for premenopausal women with hormone-receptor positive tumors. Anastrozole is only approved for the treatment of postmenopausal women with hormone-receptor positive tumors. However, premenopausal women in this study were able to take this drug while receiving ovarian suppression.

The results: After approximately five years, treatment with zoledronic acid combined with hormone therapy reduced a woman's risk of recurrence by 35%, compared with women who received hormone therapy alone. There was no difference in the reduction of the risk of recurrence between the tamoxifen and anastrozole. Women in this study had no unexpected side effects, and the overall occurrence of side effects was low. 

What this means for patients

“It's very exciting to find that in addition to preventing bone loss in women receiving hormone therapy for breast cancer, zoledronic acid can also reduce the likelihood that breast cancer will return in some women,” said lead author Michael Gnant, MD, Professor of Surgery at the Medical University of Vienna and President of the Austrian Breast and Colorectal Cancer Study Group. “Future research will focus on developing the appropriate treatment schedule and determining which women will benefit the most from this treatment.”

What to ask the doctor

• What is the stage of my breast cancer?
• What is the chance that the cancer will recur?
• What is my current treatment plan?
• Would I benefit from treatment to reduce bone loss?

For more information

Cancer.Net Guide to Breast Cancer

What to Know: ASCO's Guideline on Bisphosphonates for Breast Cancer