(RxWiki News) Previous research suggested that a common medicine used to treat osteoporosis had the positive side effect of reducing breast cancer risk. New research suggests that may not be true.
A new study suggests that bisphosphonates help with osteoporosis but may not lower the chances of a patient developing breast cancer.
"Talk to your gynecologist about managing menopause."
The study was written by Trisha Hue, PhD, MPH, of the University of California-San Francisco, and colleagues.
The researchers set out to test previous studies that suggested bisphosphonates, commonly used to treat osteoporosis, could protect postmenopausal women from breast cancer.
Osteoporosis, common in older women, is a loss of bone density that makes bones more brittle and easier to break in a fall or other injury. Menopause is the natural stopping of menstruation.
The authors reviewed two studies to compare incidence of breast cancer and treatment with bisphosphonates.
The first study included 6,459 women ages 55 to 81. The women were randomly assigned a bisphosphonate treatment or a placebo, which caused no effect.
The rate of breast cancer in the average of 3.8 years of follow-up was 1.5 percent for the placebo group and 1.8 percent in the group receiving bisphosphonate treatment.
In the second study, 7,765 women ages 65 to 89 were randomly assigned either a placebo or bisphosphonate.
In the average of 2.8 years of follow-up, the rate of breast cancer was 0.8 percent in the placebo group and 0.9 percent in the group that received bisphosphonate.
The authors concluded that bisphosphonate did not guard against breast cancer in women who had gone through menopause.
"These data provide evidence that three to four years of treatment with bisphosphonate … therapy does not reduce the risk of incident breast cancer in postmenopausal women,” the authors wrote.
The study was published online Aug. 11 in the peer-reviewed JAMA Internal Medicine.
Pharmaceutical companies Merck and Co. and Novartis provided funding. The authors disclosed the funding sources and noted the companies were not involved in the design, execution or analysis of the research.
