Dr. Aft on Bisphosphonates for Breast Cancer
Rebecca L. Aft, MD, PhD, professor of surgery at the Washington University School of Medicine in St. Louis and a physician at Siteman Cancer Center, discusses the use of bisphosphonates for patients with breast cancer.
In a study, patients were randomized to receive a bisphosphonate at the time of neoadjuvant chemotherapy and were analyzed for the presence of disseminating tumor cells. Results demonstrated that patients who received a bisphosphonate had fewer disseminating tumor cells in their bone marrow. In a subgroup analysis, patients with triple-negative disease who received bisphosphonates had a decreased risk of developing metastatic disease.
The mechanism of action of bisphosphonates is hypothesized to affect the bone marrow's microenvironment. It is also hypothesized that cancer cells in the bone marrow or tumors can release activators into the bone marrow which cause increased bone turnover and activation of tumor-enhancing cells. By turning off osteoclasts, Aft says, it is possible to decrease bone turnover and decrease the release of growth factors, creating a more hostile environment for disseminating tumor cells in the bone marrow.