A treatment for high blood pressure has been shown to greatly increase breast cancer risk.
Antihypertensive medications are prescribed more often than any other medicine in the U.S. A recent study found a correlation between calcium-channel blocker (used for the treatment of hypertension) and breast cancer, a Newswise press release reported.
"Evidence regarding the relationship between different types of antihypertensive and breast cancer risk is sparse and inconsistent, and prior studies have lacked the capacity to assess impacts of long-term use," the study said.
The study observed women between the ages of 55 and 74 who lived in the "Seattle-Puget Sound metropolitan area." Eight-hundred of the patients had invasive ductal breast cancer, 1,027 had invasive lobular breast cancer, and 856 were cancer-free.
The study teamed measured each patient's individual risk of breast cancer, and factored in if they were taking calcium-channel blockers and how recently they had done so.
Women who had taken the hypertension medications for 10 years or longer were 2.5 times more likely to get breast cancer. This was fairly standard for all types of calcium-channel blockers, Bloomberg reported.
Other high blood pressure medications, such as "diuretics, β-blockers and angiotensin II antagonist," did not increase breast cancer risk, the press release reported.
"While some studies have suggested a positive association between calcium-channel blocker use and breast cancer risk, this is the first study to observe that long-term current use of calcium-channel blockers in particular are associated with breast cancer risk. Additional research is needed to confirm this finding and to evaluate potential underlying biological mechanisms," the study said.
Patricia F. Coogan, of the Slone Epidemiology Center at Boston University, thinks the matter deserves further study.
"Given these results, should the use of CCBs [calcium-channel blockers] be discontinued once a patient has taken them for 9.9 years? The answer is no, because these data are from an observational study, which cannot prove causality and by itself cannot make a case for change in clinical practice," Coogan said.
"Should the results be dismissed as random noise emanating from an observational study? The answer is no, because the data make a convincing case that the hypothesis that long-term CCB use increases the risk of breast cancer is worthy of being pursued," she said.
