Calcium Channel Blockers and
the Risk of Cancer

Abstract & Editor's Comments
Lynn Rosenberg, ScD; R. Sowmya Rao, MS; Julie R. Palmer, ScD;
Brian L. Strom, MD; Paul D. Stolley, MD; Ann G. Zauber, PhD;
M. Ellen Warshauer, MS; Samuel Shapiro, MB
JAMA. 1998;279:1000-1004

Context.—Recent epidemiologic studies have raised the concern that calcium channel blocker use may increase the risk of cancer overall and of several specific cancers.

Objective.—To assess whether calcium channel blocker use increases the risk of cancer overall and of specific cancers.

Design.—Case-control drug surveillance study based on data collected from 1983 to 1996.

Setting.—Hospitals in Baltimore, Md, New York, NY, and Philadelphia, Pa.

Patients.—A total of 9513 patients aged 40 to 69 years with incident cancer of various sites and 6492 controls aged 40 to 69 years admitted for nonmalignant conditions.

Main Outcome Measures.—Incident cancer overall and 23 specific cancers.

Results.—Calcium channel blocker use was unrelated to the risk of cancer overall (relative risk [RR], 1.1; 95% confidence interval [CI], 0.9-1.3). Use was not significantly associated with increased risks of individual cancers, including those previously implicated, except cancer of the kidney (RR, 1.8; 95% CI, 1.1-2.7). Recent use, use for 5 or more years, and use of individual calcium channel blocker drugs were also not associated with cancer incidence. Use of beta-blockers and angiotensin-converting enzyme inhibitors was generally unrelated to cancer overall or individual cancers, but both were associated with kidney cancer (RR, 1.8; 95% CI, 1.3-2.5; and RR, 1.9; 95% CI, 1.2-3.0, respectively).

Conclusions.—The present study suggests that the use of calcium channel blockers is unrelated to an increase in the overall risk of cancer or of individual cancers, except kidney cancer, which has been associated with hypertension or drugs to treat hypertension in previous studies.

From the Slone Epidemiology Unit, School of Public Health, Boston University School of Medicine, Brookline, Mass (Drs Rosenberg, Palmer, and Shapiro and Ms Rao); Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, and Division of General Internal Medicine of the Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia (Dr Strom); Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore (Dr Stolley); Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (Dr Zauber); and Department of Public Health, Cornell Medical Center, New York Hospital, New York, NY (Dr Warshauer). Dr Strom has been a consultant with Pfizer on the issue of calcium channel blockers and cancer. He has been a consultant on unrelated topics for several pharmaceutical companies that manufacture or market antihypertensive drugs. Drs Rosenberg, Shapiro, and Stolley have been consultants on unrelated topics for pharmaceutical companies that manufacture or market antihypertensive drugs. Dr Rosenberg has received research funding from Merck to study hypertension and the diagnosis of renal cancer. The Slone Epidemiology Unit has received and is currently receiving support for unrelated projects from several pharmaceutical companies, some of which manufacture or market antihypertensive drugs.

EDITOR'S NOTE.—Although the greater controversy regarding calcium channel blockers has concerned their potential for adverse coronary outcomes, a few studies showing an increased risk of cancer associated with use of such medications have been published. In this study, Rosenberg et al analyzed data from an existing hospital-based drug surveillance study to determine whether there is an association between use of calcium channel blockers and cancer. The strengths of the case-control design, namely, large numbers of subjects with the outcome of interest and large statistical power, need to be weighed against the potential biases of selection and recall. However, for this particular research question, analyses using other hypertensive medications as referent groups appear to mitigate these potential biases. Although it is extremely difficult to "prove" a null finding in epidemiologic studies, this article provides evidence that there is no great increase in risk of cancer associated with calcium channel blockers.

David H. Mark, MD, MPH, Contributing Editor

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