Information sourced from NEJM Journal Watch:
Calcium-Channel Blockers Might Be Associated with Excess Breast Cancer Risk
Other antihypertensives did not show this effect.
Several small studies have suggested an association between calcium-channel blocker (CCB) use and excess risk for breast cancer; other studies, particularly those with short follow-up, have shown no relation. To understand these conflicting results, investigators identified 1907 women (age range, 55 74) with breast cancer (invasive ductal or invasive lobular carcinomas) from a surveillance registry; cases were age-matched to 856 controls without breast cancer from a community population. Breast cancer patients were more likely to have family histories of breast cancer, be current alcohol users and smokers, and be current users of combined estrogen-progestin hormone therapy.
After adjustment for potentially confounding clinical and demographic variables, risk for both ductal and lobular breast cancer was about 2.5 times higher among current long-term CCB users ( ¥10 years) than among women who never used antihypertensive medications. Researchers found no excess risk associated with use of other classes of antihypertensives or short-term (<10 years) CCB use.
That calcium-channel blockers stand out compared with other classes of antihypertensives strengthens the association between CCBs and breast cancer, but no known biological mechanism accounts for these findings. An editorialist notes that calcium-channel blockers are the ninth most commonly prescribed drug class in the U.S. and would represent a major modifiable risk factor for breast cancer if these results were confirmed. These findings are worrisome but do not lead yet to specific clinical recommendations.
Thomas L. Schwenk, MD reviewing Li CI et al. JAMA Intern Med 2013 Aug 5. Coogan PF. JAMA Intern Med 2013 Aug 5.
Li CI et al. Use of antihypertensive medications and breast cancer risk among women aged 55 to 74 years. JAMA Intern Med 2013 Aug 5; [e-pub ahead of print]. [PubMed ® abstract]
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