(Press-News.org) An analysis of data from two randomized clinical trials finds that three to four years of treatment with bisphosphonates to improve bone density is not linked to reduced risk of invasive postmenopausal breast cancer.
The authors are Trisha F. Hue, Ph.D., M.P.H., of the University of California, San Francisco, and colleagues.
Some studies have suggested that bisphosphonates, which are commonly used to treat osteoporosis, may have antitumor and antimetastatic properties. Some observational studies have suggested bisphosphonates may protect women from breast cancer.
The authors analyzed the relationship of postmenopausal breast cancer and bisphosphonate use by examining data from two randomized, double-blind, placebo-controlled trials. The Fracture Intervention Trial (FIT) randomly assigned 6,459 women (ages 55 to 81 years) to alendronate or placebo with an average follow-up of 3.8 years. The Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly-Pivotal Fracture Trial (HORIZON-PFT) randomly assigned 7,765 women (ages 65 to 89 years) to annual intravenous zoledronic acid or placebo with an average follow-up of 2.8 years. The authors compared rates of breast cancer in the bisphosphonate treatment groups to the placebo groups.
There was no significant difference in breast cancer rates between the bisphosphonate and placebo groups. In FIT, the breast cancer rate was 1.5 percent in the placebo group and 1.8 percent in the alendronate group. In HORIZON-PFT the rate was 0.8 percent in the placebo group and 0.9 percent in the zoledronic acid group. There also was no significant difference when data from the two trials were combined.
"These data provide evidence that three to four years of treatment with bisphosphonate, alendronate or zoledronic acid, therapy does not reduce the risk of incident breast cancer in postmenopausal women. The discrepancy between our results and the reports of associations in observational studies may be an example of indication bias and illustrates the limitation and hazard of drawing conclusions about treatment effects from observational studies (even those that are very well done) and emphasizes the value of confirming such associations in randomized trials. The effect of bisphosphonate treatment on breast cancer risk in nonosteoporotic populations should be investigated in other randomized trials."
In a related editor's note, Joseph S. Ross, M.D., M.H.S., a JAMA Internal Medicine associate editor, writes: "Whereas these findings highlight why it is so important for new therapies to be evaluated using RCTs (randomized clinical trials), they also reinforce the importance of assessing the methodological rigor of observational studies before interpreting real-world effects."
"Just as we closely scrutinize RCT design, so must we understand the quality and statistical power of the data used for observational studies, how participants were identified, the duration of follow-up, the end points examined, and the analytical strategy used. Observational studies are particularly valuable for clinical situations unlikely to be tested using RCTs, and many provide valid and reliable real-world evidence," Ross continues.
"Thus, whereas we all can remember examples of when RCTs and observational studies differed, less memorable are the even more numerous examples in which results were consistent. In the end, we should be open to all types of evidence and rely on rigorous clinical science to guide practice," Ross concludes.
INFORMATION:
JAMA Intern Med. Published online August 11, 2014. doi:10.1001/jamainternmed.2014.3634.
An author made a conflict of interest disclosure. Support for FIT was provided by Merck & Co., and support for HORIZON-PFT was provided by Novartis, Basel, Switzerland. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
To contact author Trisha F. Hue, Ph.D., M.P.H., call Laura Kurtzman at 415-476-3163 or email Laura.Kurtzman@ucsf.edu[mailto]. To contact editor's note author Joseph S. Ross, M.D., M.H.S., call JAMA Media Relations at 312-464-5262 or email mediarelations@jamanetwork.org.
Bisphosphonates for osteoporosis not associated with reduced breast cancer risk
2014-08-11
ELSE PRESS RELEASES FROM THIS DATE:
Medicinal oil reduces debilitating epileptic seizures associated with Glut 1 deficiency
2014-08-11
DALLAS – Aug. 11, 2014 – Two years ago, the parents of Chloe Olivarez watched painfully as their daughter experienced epileptic seizures hundreds of times a day. The seizures, caused by a rare metabolic disease that depleted her brain of needed glucose, left Chloe nearly unresponsive, and slow to develop.
Within hours, treatment with an edible oil dramatically reduced the number of seizures for then-4-year-old Chloe, one of 14 participants in a small UT Southwestern Medical Center clinical trial.
"Immediately we noticed fewer seizures. From the Chloe we knew two years ...
An easier way to manipulate malaria genes
2014-08-11
Plasmodium falciparum, the parasite that causes malaria, has proven notoriously resistant to scientists' efforts to study its genetics. It can take up to a year to determine the function of a single gene, which has slowed efforts to develop new, more targeted drugs and vaccines.
MIT biological engineers have now demonstrated that a new genome-editing technique, called CRISPR, can disrupt a single parasite gene with a success rate of up to 100 percent — in a matter of weeks. This approach could enable much more rapid gene analysis and boost drug-development efforts, says ...
Kessler Foundation scientists link environment & inclusion in adults with disabilities
2014-08-11
West Orange, NJ. August 11, 2014. Kessler Foundation researchers have identified an association between the built environment and disability-related outcomes for adults with physical impairments. The article, Disability and the built environment: an investigation of community and neighborhood land uses and participation for physically impaired adults, was published in the July issue of Annals of Epidemiology (doi: 10.1016/j.annepidem.2014.05.003). The authors are Amanda Botticello, PhD, MPH, and Nicole Cobbold, BS, of Kessler Foundation, and Tanya Rohrbach, MS, of Raritan ...
A global temperature conundrum: Cooling or warming climate?
2014-08-11
MADISON, Wis. — When the Intergovernmental Panel on Climate Change recently requested a figure for its annual report, to show global temperature trends over the last 10,000 years, the University of Wisconsin-Madison's Zhengyu Liu knew that was going to be a problem.
"We have been building models and there are now robust contradictions," says Liu, a professor in the UW-Madison Center for Climatic Research. "Data from observation says global cooling. The physical model says it has to be warming."
Writing in the journal Proceedings of the National Academy of Sciences today, ...
Follow the radio waves to exomoons, UT Arlington physicists say
2014-08-11
Scientists hunting for life beyond Earth have discovered more than 1,800 planets outside our solar system, or exoplanets, in recent years, but so far, no one has been able to confirm an exomoon. Now, physicists from The University of Texas at Arlington believe following a trail of radio wave emissions may lead them to that discovery.
Their recent findings, published in the Aug. 10 issue of The Astrophysical Journal, describe radio wave emissions that result from the interaction between Jupiter's magnetic field and its moon Io. They suggest using detailed calculations about ...
Digoxin tied to increased risk of death in patients with atrial fibrillation
2014-08-11
In An Account of the Foxglove and Some of its Medical Uses, published in 1785, Sir William Withering cautioned readers that extracts from the plant foxglove, also called digitalis, was not a perfect drug. "Time will fix the real value upon this discovery," he wrote.
Now, more than 200 years later, researchers at the Stanford University School of Medicine have validated Withering's warning with the discovery that patients with atrial fibrillation — a rapid and irregular heart rhythm — who are treated with the digitalis-derivative digoxin are more likely to die than similar ...
Bioengineers make functional 3-D brain-like tissue model
2014-08-11
MEDFORD/SOMERVILLE, Mass. (August 11, 2014) --The human brain remains one of the least understood organs in the human body, because of its complexity and the difficulty of studying its physiology in the living body. Tufts University researchers today announced development of the first reported complex three-dimensional model made of brain-like cortical tissue that exhibits biochemical and electrophysiological responses and can function in the laboratory for months. The engineered tissue model offers new options for studying brain function, disease and trauma, and treatment. ...
Trapped atmospheric waves triggered more weather extremes
2014-08-11
It has been linked to a recently discovered mechanism: the trapping of giant waves in the atmosphere. A new data analysis now shows that such wave-trapping events are indeed on the rise.
"The large number of recent high-impact extreme weather events has struck and puzzled us," says Dim Coumou, lead author of the study conducted by a team of scientists from the Potsdam Institute for Climate Impact Research (PIK). "Of course we are warming our atmosphere by emitting CO2 from fossil fuels, but the increase in devastating heat waves in regions like Europe or the US seems ...
Preemies' gut bacteria may depend more on gestational age than environment
2014-08-11
Scientists believe babies are born with digestive systems containing few or no bacteria. Their guts then quickly become colonized by microbes — good and bad — as they nurse or take bottles, receive medication and even as they are passed from one adoring relative to another.
However, in infants born prematurely, researchers at Washington University School of Medicine in St. Louis have found that the population of bacteria in babies' gastrointestinal tracts may depend more on their biological makeup and gestational age at birth than on environmental factors. The scientists ...
Bioengineers create functional 3-D brain-like tissue
2014-08-11
Bioengineers have created three-dimensional brain-like tissue that functions like and has structural features similar to tissue in the rat brain and that can be kept alive in the lab for more than two months.
As a first demonstration of its potential, researchers used the brain-like tissue to study chemical and electrical changes that occur immediately following traumatic brain injury and, in a separate experiment, changes that occur in response to a drug. The tissue could provide a superior model for studying normal brain function as well as injury and disease, and ...