Women who take osteoporosis medications called bisphosphonates had fewer invasive breast cancers than women who did not take the drugs, according to research presented today at the American Assn. for Cancer Research / San Antonio Breast Cancer Symposium.
Dr. Rowan Chlebowski, an oncologist at the Los Angeles Biomedical Research Institute, reviewed data from the Women's Health Initiative, an observational study of more than 150,000 healthy post-menopausal women. He found that women who used bisphosphonates, mostly the brand name drug Fosamax, had 32% fewer cases of invasive breast cancer.
There has been some speculation that bisphosphonates may impact cancer growth because another study found that giving the bisphosphonate zoledronic acid intravenously every six months resulted in fewer breast cancer recurrences in women who had been diagnosed with the disease. However, bisphosphonates are often prescribed to women with low bone mineral density, and poor bone density is itself associated with lower breast cancer incidence. However, Chlebowski controlled for that association in his analysis in order to gauge the impact of the medications regardless of bone density.
"The idea that bisphosphonates could reduce breast cancer incidence is very exciting because there are about 30 million prescriptions for these agents written annually in the U.S. targeting bone health, and more could easily be used to counteract both osteoporosis and breast cancer." Chlebowski said in a news release.
Several randomized clinical trials assessing bisphosphonates and breast cancer recurrence are underway.
-- Shari Roan
Photo: On the left is a magnified illustration of healthy bone. On the right, a magnified illustration of bone weakened by osteoporosis. Credit: PR NewsFoto