When the drug was given along with chemotherapy for three months before breast cancer surgery, it reduced the number of women who had tumor cells in their bone marrow at the time of surgery.
Tumors shed thousands of cells, which spread throughout the body and are referred to as disseminated tumor cells (DTCs). Breast cancer DTCs often lodge in bone marrow where bone growth factors help them survive.
Chemotherapy can increase bone turnover and bone growth factors, potentially exacerbating the problem of DTCs in the bone, which can resurface later to cause metastatic disease in cancer patients.
Researchers believe that zoledronic acid inhibits the release of growth factors that help support the growth of DTCs.
In this randomized phase II clinical trial, researchers split 109 women with newly diagnosed stage II or stage III breast cancer into two groups. The control group received chemotherapy alone, while the other received a combination treatment of chemotherapy and zoledronic acid. After three months of therapy, patients with DTCs in their bone marrow decreased from 43 percent to 30 percent in the combination group, compared with a decrease from 48 percent to 47 percent in the control group. This result approached statistical significance.
Zoledronic acid treatment with chemotherapy had additional benefits. Women in the combination group experienced significant gains in bone density after 12 months. This is helpful for breast cancer patients, who often develop osteoporosis as a side effect of chemotherapy and other breast cancer treatments.
The study also suggested that zoledronic acid may help fight certain types of breast tumors directly. Aft speculates that the drug may stop the tumor from making its own blood supply, modify the immune system in a way that makes it harder for tumor cells to survive or even cause the cancer cells to commit suicide.....
Ref : http://www.ncbi.nlm.nih.gov/pubmed/20362507?dopt=Abstract