December 3, 2014
Risk of Breast Cancer Lower Than Reported With Calcium Channel Blockers 

Murray, UT—Despite concerns that calcium channel blockers (CCB) increase the risk of developing breast cancer in women who take the drugs for high blood pressure, a new study suggests that the antihypertensive medications can continue to be used with little worry.

Last year, research from the Fred Hutchinson Cancer Research Center in Seattle suggested that the odds of developing breast cancer were 2.5 times higher for women who take calcium channel blockers. A study presented recently at the 2014 American Heart Association Scientific Sessions in Chicago, however, indicates only small or no increased risk.

For the recent study, researchers from Intermountain Medical Center Heart Institute in Murray, Utah, analyzed the records of more than 3,700 women who had no history of breast cancer and who had long-term use of CCB medications to control their blood pressure.

Results indicated only minimal increase in breast cancer risk in one study and a 50% reduced risk in a second. As a result, the authors recommend the continued use of CCBs to help prevent heart attack and stroke.

“We found no robust data that calcium channel blocker medications increase a person's risk of breast cancer,” said Jeffery L. Anderson, MD, a cardiologist and researcher at the Intermountain Medical Center Heart Institute. “Given the important role calcium channel blocker medications play in treating heart conditions, we think it's premature to discontinue their use. At this point we recommend that patients continue taking these medications to treat their hypertension.”

Researchers compared women who were prescribed CCBs to a similar cohort not receiving the medications. In the review of a general population medical records database, breast cancer development was found to be 1.6 times higher in those using CCBs; authors call those findings “significant” but point out they are much smaller than the effect reported by the Seattle group.

On the other hand, data collected from patients treated in the Intermountain Cardiac Catheterization Laboratory showed a reverse relationship: The risk of developing breast cancer for women who took CCBs was reduced by half.

Because of the contrasting results of the two independent analyses, study authors suggest that other factors such as selection bias could be causing changes in breast cancer risks, not the medications.

“Given the important role of CCBs in clinical medicine, further studies are warranted, including randomized trials to assess CCB safety with respect to breast cancer risk,” they conclude.

U.S. Pharmacist Social Connect