An osteoporosis drug called zoledronic acid has been found effective in protecting women with breast cancer against bone loss, a main side effect of being treated with a class of drugs called aromatase inhibitors for breast cancer. Results of this study, called Z-FAST, were recently published online in Cancer, a journal from the American Cancer Society.
Aromatase inhibitors work by reducing estrogen levels in women, thereby causing bone loss, which can lead to an increased risk of bone fractures. Since many postmenopausal women are treated with these potentially life-saving therapies over the course of many years, a study was conducted to determine whether or not taking an osteoporosis therapy along with an aromatase inhibitor could help prevent or treat bone loss.
Researchers at the University of Pittsburgh Cancer Institute enrolled and randomized a total of 602 postmenopausal women with early breast cancer who were receiving letrozole, one type of aromatase inhibitor, to receive either zoledronic acid at the same time as letrozole therapy was initiated or to only receive zoledronic acid after bone loss was measured or a bone fracture occurred.
At the end of the study, researchers found that bone density increased significantly over five years in women who received zoledronic acid simultaneously with letrozole therapy. In contrast, significant decreases in bone density were observed in the group of women who received zoledronic acid only after bone loss was observed. However, once receiving zoledronic acid therapy was given to this group of women, the rate of bone loss slowed down.
In conclusion, results from this study show that bone loss resulting from an aromatase inhibitor can be prevented with an osteoporosis drug, and that even if the use of the osteoporosis drug is delayed, it can still work to help reverse bone loss and be of benefit to postmenopausal women with early stage breast cancer.
Source: Cancer Press Release