Our meta-analysis findings do not support a protective effect of statins against breast cancer. However, this conclusion is limited by the relatively short follow-up times of the studies analyzed. Further studies are required to investigate the potential decrease in breast cancer risk among long-term statin users.

Statins have been suggested to prevent prostate cancer. Our aim was to examine statin use in relation to both total prostate cancer and the more clinically important advanced prostate cancer, through a detailed metaanalysis of the epidemiologic studies published on the subject in peer-reviewed literature. A comprehensive search for articles published up to November 2007 was performed, reviews of each study were conducted and data were abstracted. Prior to metaanalysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the randomeffects model. Subgroup and sensitivity analyses were also performed. Nineteen studies [6 randomized clinical trials (RCTs), 6 cohort and 7 case-control studies] contributed to the analysis. There was no evidence of an association between statin use and total prostate cancer among either RCTs (RR 5 1.06, 95% CI: 0.93-1.20) or the observational studies (RR 5 0.89, 95% CI: 0.65-1.24). However, high heterogeneity was detected among the observational studies. Moreover, long-term statin use did not significantly affect the risk of total prostate cancer (RR 5 0.93, 95% CI: 0.77-1.13). In contrast, synthesis of the available reports that had specifically examined statin use in relation to advanced prostate cancer indicated a protective association (RR 5 0.77, 95% CI: 0.64-0.93). Our results do not support the hypothesis that statins reduce the risk of total prostate cancer. However, further research is required to investigate whether the particular association of statin use with lower risk of advanced prostate cancer is indeed causal. ' 2008 Wiley-Liss, Inc.Key words: statins; prostate cancer; chemoprevention; epidemiology; metaanalysis Prostate cancer represents the second most commonly diagnosed malignancy among men in the world. However, it is in first place in developed countries. It is also among the 3 most common causes of cancer death in the western population.1 Therefore, there is a definite need to identify and develop agents for prostate cancer chemoprevention.Recent research on a class of pharmacologic agents that reduce plasma cholesterol, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), has shown promise in chemoprevention of prostate cancer. The interest regarding a possible link between statins and prostate cancer stems from experimental evidence of a positive association between cholesterol and prostate cancer. [2][3][4][5] In addition, laboratory data indicate that statins inhibit prostate cancer cell proliferation and induce tumor-specific apoptosis in vitro. 6,7While the mechanism remains unclear, some randomized clinical trials (RCTs) with cancer as a secondary endpoint and several observational epidemiologic studies have also evaluated the relationship between statin use and prostate cancer risk. The findings from these studies have been inconsistent. Some studies reported that the use of these drugs is inversely related to the risk of prostate c...

Our meta-analysis results do not support the hypothesis that statins strongly reduce the risk of colorectal cancer, when taken for management of hypercholesterolemia. However, we cannot rule out a modest reduction in risk or an effect associated with higher doses of statins.