THURSDAY, April 8 (HealthDay News) -- Women with locally advanced breast cancer may reduce the chance of cancer spreading to other parts of the body by taking zoledronic acid, a bone strengthening-drug, along with chemotherapy, because it results in fewer disseminated tumor cells (DTCs) in bone marrow, according to research published online April 1 in The Lancet Oncology.
Rebecca Aft, M.D., of the Washington University School of Medicine in St. Louis, and colleagues conducted a phase 2 trial of 120 women who had locally advanced breast cancer. They were randomized to either 4 mg of zoledronic acid every three weeks for one year starting with their first chemotherapy dose or to chemotherapy alone. At three months, 109 bone marrow samples were available for analysis.
At baseline, the researchers found that DTCs were detected in 26 of the 60 patients in the zoledronic acid group and 28 of the 58 patients in the control group. At three months, 17 of 56 patients receiving zoledronic acid versus 25 of 53 patients not receiving the drug had detectable DTCs. A year after treatment, there was not a significant difference in the number of patients with detectable tumor cells (40 percent for the zoledronic acid group, 33 percent for controls). The most common grade 3 to 4 toxicities were thrombosis (five patients in the zoledronic acid group and two in the control group) and infection (five patients in the zoledronic acid group and six in the control group).
"Our study supports the hypothesis that the antimetastatic effects of zoledronic acid may be through effects on DTCs," the authors write. "Fewer women had detectable DTCs after neoadjuvant chemotherapy with concurrent zoledronic acid than with chemotherapy alone, and zoledronic acid appeared to decrease the rate at which DTC-negative breast cancer patients developed subsequent micrometastatic disease at three months."
The study was funded by Novartis Pharmaceuticals and Pfizer Inc., and several of the study authors reported financial relationships with these companies and Sanofi-Aventis.
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