Calcium channel blocker use and the risk of prostate cancer☆

A recent study suggested that the risk of all cancers, including prostate cancer, is increased by the use of calcium channel blockers. The objective of this study was to determine whether prostate cancer is associated with calcium channel blocker use. A case-control study was conducted in Massachusetts using cases diagnosed from December 1992 through February 1995. Cases were men identified by tumor registrars who were less than 70 years old with newly diagnosed prostate cancer. Controls were men with no history of prostate cancer or symptoms of undiagnosed prostate cancer, and were matched to the cases on precinct of residence and half-decade of age. A total of 1217 cases of prostate cancer and 1400 community controls are included in this analysis. Data were collected by telephone interview. Multiple logistic regression was used to estimate relative risks for calcium channel blockers use while controlling for confounding. The relative risk for prostate cancer for any use of calcium channel blockers relative to nonuse was 1.2 (95% confidence interval [CI], 0.9-1.5). There was no evidence of a trend according to duration of use. When the analysis was confined to symptomatic men, the relative risk estimate was 1.1 (0.8-1.4) overall and 1.2 (0.8-1.7) among those aged 65 to 69 years. Relative risk estimates for the use of other classes of antihypertensive drugs among symptomatic men were close to 1.0; the corresponding estimates among asymptomatic men were generally further from 1.0. These findings suggest that calcium channel blockers do not increase the risk of prostate cancer. The differences in the relative risk estimates between symptomatic and asymptomatic men are compatible with detection bias. Because of the widespread use of Prostate-Specific Antigen testing for early detection of prostate cancer, potential detection bias needs to be considered in future studies of prostate cancer.