Blood pressure drug could up risk for cancer
Study eyes long-term use
NEW YORK — Using a type of blood pressure drug for more than a decade may raise breastcancer risk, a study found, the first potential link between long-term use of the popular medicines and the most common malignancy among women.
Women who took blood pressure drugs called calcium- channel blockers, like Pfizer’s Norvasc, for 10 years or longer had a 2.5 times higher risk of developing breast cancer than those who never took the medicine or who used other blood pressure treatments, according to research published today in JAMA Internal Medicine.
The study is the first to find that long-term use of calcium-channel blockers is associated with a higher risk of breast cancer, the authors said. More studies are needed to replicate the findings and to better understand why the class of medicines may raise risk of the disease, said Christopher Li, the lead study author.
“While this is an intriguing finding, much more work still needs to be done,” Li, head of the Translational Research Program at the Fred Hutchinson Cancer Research Center in Seattle, said Monday in an email. “While we appreciate that these results may cause concern for women currently using these medications, we do not think that they should change current clinical practice because they require confirmation and because of the importance of managing hypertension effectively.”
Blood pressure drugs are the most commonly prescribed medicines in the U.S., the authors said. More than 678 million blood pressure prescriptions were filled in 2010, about 98 million of which were for calcium-channel blockers.
Calcium-channel blockers lower blood pressure by relaxing blood vessels and preventing calcium from entering cells. Other treatments for the condition include beta blockers, which make the heart beat slower and with less force, dropping blood pressure; diuretics, which drain the body of excess fluid that may increase pressure; and angiotensin-converting enzyme, or ACE, inhibitors that prevent the body from producing angiotensin, which can narrow blood vessels.
The study included 1,960 women with breast cancer and 891 women without the disease. They were interviewed to determine which blood pressure treatments they used and for how long.
The data show the current use of calcium-channel blockers for 10 years or more increased breast cancer risk by about 2.5 times. Other blood pressure treatments used long term didn’t have similar risks, the authors wrote.
More than 232,000 women will be diagnosed with breast cancer in the United States this year and more than 39,600 will die of the disease, according to the National Cancer Institute, which funded the study.