Israeli scientists find bisphosphonate drugs taken by millions of women to prevent bone loss lower the chance of colorectal cancer.
Millions of women take bisphosphonate drugs to prevent bone loss from osteoporosis. Now, an international team of researchers led by Dr. Gad Rennert of the Technion-Israel Institute of Technology Faculty of Medicine has discovered a 59 percent reduced risk of postmenopausal colorectal cancer in those who use these drugs for more than one year.
These findings point to a possible role for bisphosphonates in cancer prevention, according to Rennert, chairman of the department of community medicine and epidemiology at the Carmel Medical Center of Clalit Health Services in Haifa. The study results were published online February 14 in the Journal of Clinical Oncology.
“We formerly identified a new class of drugs associated with a reduced risk of breast cancer,” says Rennert. “And now, by showing a similar effect on colorectal cancer risk reduction, we can assume that this class of medications has a broad effect — not necessarily limited to a specific cancer site.”
The connection still has to be proven through randomized trials. If the trials support Rennert’s assumption, doctors could start recommending bisphosphonate-based medications for preventing cancer in the general population.
Preventing a particularly deadly disease
Colorectal cancer is among the most common cancers in Western countries, with more than 150,000 new cases diagnosed every year. In the United States, 50,000 people die of this type of cancer each year.
Rennert explains that while colorectal cancer is generally caused by poor dietary habits and lack of physical activity, several medications may be helpful in staving it off, such as aspirin and cholesterol-lowering statins. Based on the new study, “we can add bisphosphonates to the list of tools for potential prevention of colorectal cancer,” he says.
The study was based on data extracted from the Molecular Epidemiology of Colorectal Cancer (MECC) study, one of the largest population-based case-control studies of colorectal cancer. MECC was a collaboration between the University of Michigan and the Technion-affiliated National Israeli Cancer Control Center from 1998 to 2004 involving 4,200 individuals.
Poring over pharmacy records to evaluate the use of bisphosphonates in 1,866 postmenopausal female MECC participants, the researchers found that the use of bisphosphonates prior to diagnosis was strongly associated with a significant reduced relative risk for colorectal cancer.
This was true even after making adjustments for a large variety of known risk or protective factors for colorectal cancer, such as family history, dietary components, physical activity, body mass index and the use of medications such as aspirin, statins and hormones.