Lipid-lowering medication and risk of cancer

LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies

Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.

Statin use and risk of pancreatic cancer: results from a large, clinic-based case-control study

BACKGROUND

Statins are cholesterol-lowering medications with pleiotropic effects, including alterations in growth signaling, as well as immunomodulatory and anti-inflammatory effects that may alter cancer risk. Evidence from previous epidemiologic studies is inconsistent about whether statin use is associated with a reduced risk of pancreatic cancer (PC).

METHODS

Patients with confirmed diagnoses of PC (cases) were recruited from medical and surgical oncology clinics, with controls (frequency-matched by sex and age) recruited from general medicine clinics, at a high-volume academic medical center over a 6-year period (2006-2011). Direct interviews were conducted with an epidemiological risk factor questionnaire covering topics such as medical history, lifestyle factors, and medication usage. Adjusted multivariable logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) as estimates of the relative risk of PC.

RESULTS

Data were obtained from 536 cases and 869 controls. Ever use of statins was associated with a 34% reduced PC risk (OR, 0.66; 95% CI, 0.47-0.92). In sex-stratified analyses, risk was statistically significantly reduced in men only (OR for men, 0.50; 95% CI, 0.32-0.79; OR for women, 0.86; 95% CI, 0.52-1.43). Duration of use was inversely associated with PC risk (>10-year use: overall OR, 0.51; OR for men, 0.41; 95% CI, 0.21-0.80; P(trend)  = .006).

CONCLUSIONS

This is the largest case-control study to demonstrate an inverse association between statin use and PC risk. Risk reduction in statin users appears to be sex-specific and is more pronounced in long-term users. Further research is warranted to better characterize this association and clarify the roles of underlying biologic mechanisms.

Statins are associated with a reduced risk of hepatocellular cancer: a systematic review and meta-analysis

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Several studies have shown that statins could have chemopreventive effects on HCC. We performed a systematic review and meta-analysis of studies that evaluated the effects of statins on the risk of HCC.

METHODS

We conducted a systematic search of MEDLINE, Embase, and Web of Science through May 2012 and manually reviewed the literature. Studies were included if they evaluated and clearly defined exposure to statins, reported the incidence of HCC, and reported relative risks or odds ratios (ORs) or provided data for their estimation. Ten studies reporting 4298 cases of HCC in 1,459,417 patients were analyzed. Summary OR estimates with 95% confidence intervals (CIs) were calculated using the random effects model. Statistical heterogeneity was assessed with the Cochran's Q statistic and I(2) statistic.

RESULTS

Statin users were less likely to develop HCC than statin nonusers (adjusted OR, 0.63; 95% CI, 0.52-0.76), although the results were heterogeneous (P = .01, I(2) = 59%). This heterogeneity could be accounted for by study location (Asian population [n = 4]: adjusted OR, 0.52; 95% CI, 0.42-0.64; Western population [n = 6]: adjusted OR, 0.67; 95% CI, 0.53-0.85) and design (observational studies [n = 7]: adjusted OR, 0.60; 95% CI, 0.49-0.73; clinical trials [n = 3]: adjusted OR, 0.95; 95% CI, 0.62-1.45).

CONCLUSIONS

Based on meta-analysis, statin use is associated with a reduced risk of HCC, most strongly in Asian but also in Western populations. Randomized clinical trials in populations at high risk for HCC (especially in Asian populations with hepatitis B) are warranted.

Use of fibrates and cancer risk: a systematic review and meta-analysis of 17 long-term randomized placebo-controlled trials

BACKGROUND

Fibrates comprise a class of well-established antilipidemic agents that significantly reduce cardiovascular events. Given the concerns of cancer with fibrate therapy, we undertook a systematic review and meta-analysis to investigate the effects of fibrates on cancer outcomes.

METHODS

We systematically searched Medline, Scopus, SCI Expanded, and the Cochrane Library for studies published up to 2012. We included randomized controlled trials (RCTs) that evaluated a fibrate therapy compared with placebo, had a minimum duration of two years, and reported data on the incidence of and/or deaths from cancer during the trial. Reviews of each study were performed and the relative data were abstracted. Pooled relative risk estimates (RR) and 95% confidence intervals (CIs) were calculated using the inverse variance weighted approach. Subgroup, sensitivity and meta-regression analyses were also conducted.

RESULTS

Seventeen RCTs, involving 44,929 participants with an average follow-up of 5.2 years, contributed to the analysis. The degree of variability between trials was consistent with what would be expected to occur by chance alone. The quantitative synthesis of data retrieved from the RCTs was not indicative of a fibrate effect on cancer incidence (780 [fibrate] vs 814 [control]; RR = 1.02, 95% CI 0.92-1.12) or cancer death (385 [fibrate] vs 377 [control]; RR = 1.06, 95% CI: 0.92-1.22). When the analysis was restricted to major RCTs, the results did not substantially change. Similarly, we found no evidence of differential effects by length of follow-up or type of fibrate. Insignificant results were also obtained for the role of fibrates in cancers of the respiratory tract, breast, colon, gastrointestinal tract, prostate, genitourinary tract, or in melanoma.

CONCLUSION

Our findings demonstrate that fibrates have a neutral effect on cancer outcomes. However, it is important to continue monitoring their long-term safety profiles.

Statin use and risk of pancreatic cancer: a meta-analysis

PURPOSE

Statins are commonly prescribed medications that potently reduce cholesterol levels and the risk of cardiovascular events. Preclinical studies suggested statins also possess cancer chemopreventive properties. However, the clinical studies provided contradictory results as to whether statins influence the risk of pancreatic cancer. Herein, we present this meta-analysis to assess the association between statin use and risk of pancreatic cancer.

METHODS

We conducted a comprehensive search up to August 2011 for the eligible studies. Pooled relative risk (RR) estimates and corresponding 95 % confidence intervals (CIs) were calculated using the inverse-variance-weighted random-effects model. Subgroup analyses were conducted where data were available. Heterogeneity was assessed by the Cochran's Q test and the I(2) statistic.

RESULTS

We included 16 studies that involving 1,692,863 participants and 7,807 pancreatic cancer cases. Pooled results only indicated a non-significant decrease of pancreatic cancer risk among all statin users (RR 0.89; 95 % CIs, 0.74-1.07). Similar results were obtained in the subgroup analyses of the long-term (more than 4 years) follow-up (RR 0.94, 0.81-1.08) and statin use (RR 0.97, 0.76-1.23), and a null association was found between lipophilic statin use and pancreatic cancer risk (RR 1.03, 0.92-1.16). No evidence of publication bias was observed in the present meta-analysis. However, significant heterogeneity was detected among all studies (p < 0.00001, I(2) = 81 %).

CONCLUSIONS

In conclusion, our results suggest that there is no association between statin use and pancreatic cancer risk, when statins are taken at daily doses for cardiovascular event prevention.

Prostate cancer and PSA among statin users in the Finnish prostate cancer screening trial

Decreased risk of advanced prostate cancer has been reported among men using statins. However, the evidence on overall prostate cancer risk is conflicting. We compared the relative risk between current users and non-users of statins or other cholesterol-lowering medications in a population undergoing systematical prostate cancer screening. The study cohort comprised of 23,320 men participating in the screening arm of the Finnish prostate cancer screening trial during 1996-2004. Information on medication use was obtained from a comprehensive national prescription database. Cox proportional hazards regression was used to calculate multivariable adjusted hazard ratios (HRs) for prostate cancer. Serum prostate-specific antigen (PSA) level was compared between current users and non-users of cholesterol-lowering drugs. Compared with medication non-users, the overall prostate cancer incidence was decreased among statin users [HR 0.75, 95% confidence interval (CI) 0.63-0.89]. The inverse association was dose-dependent with cumulative amount of statin use, and strongest for low-grade and early stage tumors. The incidence was nonsignificantly lower also among users of other types of cholesterol-lowering drugs (HR 0.62, 95% CI 0.28-1.38), but without dose-dependence. Age-adjusted median serum PSA tended to be lower among users of cholesterol-lowering drugs, but the relative risk decrease among statin users was not related to decreased PSA. Overall incidence of prostate cancer was lowered among statin users when bias due to differential PSA testing between medication users and non-users was eliminated by systematical prostate cancer screening. Cholesterol-lowering with statins seems beneficial for prostate cancer prevention.

Statin medication use and the risk of biochemical recurrence after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) Database

BACKGROUND

Although controversial, evidence suggests statins may reduce the risk of advanced prostate cancer (PC), and recently statin use was associated with prostate-specific antigen (PSA) reductions among men without PC. The authors sought to examine the association between statin use and PSA recurrence after radical prostatectomy (RP).

METHODS

The authors examined 1319 men treated with RP from the Shared Equal Access Regional Cancer Hospital (SEARCH) Database. Time to PSA recurrence was compared between users and nonusers of statin at surgery using Cox proportional hazards models adjusted for multiple clinical and pathological features.

RESULTS

In total, 236 (18%) men were taking statins at RP. Median follow-up was 24 months for statin users and 38 for nonusers. Statin users were older (P<.001) and underwent RP more recently (P<.001). Statin users were diagnosed at lower clinical stages (P=.009) and with lower PSA levels (P=.04). However, statin users tended to have higher biopsy Gleason scores (P=.002). After adjusting for multiple clinical and pathological factors, statin use was associated with a 30% lower risk of PSA recurrence (hazard ratio "HR", 0.70; 95% confidence interval "CI", 0.50-0.97; P=.03), which was dose dependent (relative to no statin use; dose equivalent<simvastatin 20 mg: HR, 1.08; 95% CI, 0.66-1.73; P=.78; dose equivalent=simvastatin 20 mg: HR, 0.57; 95% CI, 0.32-1.00; P=.05; dose equivalent>simvastatin 20 mg: HR, 0.50; 95% CI, 0.27-0.93; P=.03).

CONCLUSIONS

In this cohort of men undergoing RP, statin use was associated with a dose-dependent reduction in the risk of biochemical recurrence. If confirmed in other studies, these findings suggest statins may slow PC progression after RP.

Statins and pancreatic cancer risk: a nested case-control study

OBJECTIVE

To investigate the relationship between statin use and pancreatic cancer risk.

METHODS

A nested case-control study was conducted within the UK GPRD. Cases had a diagnosis of primary malignant neoplasia of the exocrine pancreas. Controls were matched with cases on general practice site, sex and year of birth. Exposure of interest was exposure to statins since entry into the GPRD until 1 year before the case diagnosis date. Conditional logistic regression analyses were used to generate ORs and 95% CI associated with statin use compared to non-use.

RESULTS

A total of 1,141 pancreatic cancer cases and 7,954 controls were identified. Any use of a statin since entry into the GPRD (excluding the year prior to diagnosis) was not associated with the risk of pancreatic cancer OR 0.93 (95% CI, 0.76-1.14). Neither dose nor duration of statin use affected pancreatic cancer risk. When dose and duration of statin use combined were assessed, no evidence of reduced risk was seen for long-term users of high-dose statins OR 0.71 (0.42-1.20). Statin type (simvastatin vs atorvastatin) was not associated with pancreatic cancer risk.

CONCLUSION

Statin use at doses for managing hypercholesterolaemia, in a UK population, was not associated with the risk of exocrine pancreatic cancer.

Statin use and cancer risk: a comprehensive review

IMPORTANCE OF THE FIELD

HMG-CoA inhibitors (statins), a class of drugs that reduce cholesterol, are used to manage and prevent coronary heart disease. They are among the most commonly prescribed drugs worldwide. Contrary to early concerns over the carcinogenicity of statins, a growing body of evidence suggests statins may in fact have a chemopreventive potential against cancer.

AREAS COVERED IN THIS REVIEW

In this paper, we review evidence on the association between statin use and cancer risk. Specifically, we report on clinical trials and observational studies that measured all cancer or site-specific cancers of the breast, colorectal, lung, prostate and reproductive organs associated with statin use.

WHAT THE READER WILL GAIN

An understanding of the evidence, including strengths and limitations, to support an association between statins and cancer. Information on the current state of the field and future directions are also discussed.

TAKE HOME MESSAGE

Few strong or consistent associations between statins and cancer incidence overall or for any of the sites reviewed were detected. Data for any effects of statins on cancer prognosis and secondary prevention are lacking; with the exception of consistent evidence that statins are associated with reduced risk of advanced/aggressive prostate cancer. Statins appear safe in relation to cancer risk but any chemopreventive effect in humans remains to be established and should not be recommended outside the context of clinical trials. It is encouraging that numerous trials are ongoing. The prospect of reducing the incidence and burden of some of the most prevalent cancers with safe, affordable and tolerable medication that already reduces the risk of the leading cause of death and cardiovascular disease warrants further exploration in clinical trials and observational studies of prognosis and survival.

Statin Use and Cancer Risk: An Epidemiologic Review

While the beneficial effects of hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) on cardiovascular disease are well established, much uncertainty remains about their effects on cancer. The statins inhibit the rate-limiting step in the mevalonate pathway, leading to reduced levels of cholesterol and other molecules of importance for critical cellular processes. A growing body of preclinical data indicates that statins may have antineoplastic properties, but some studies raise the possibility that statins may possess a carcinogenic potential. Clinical and observational studies of the association between statin use and cancer have been inconclusive with regard to any chemopreventive or therapeutic effect, but they do provide reassuring evidence that statins do not appear to be carcinogenic. The reasons for the varying results are unclear but they may relate to methodological issues. Additional studies, including Phase II randomized trials and epidemiological studies with accurate measures of statin use and comprehensive control for confounding factors, are needed to determine the potentially beneficially effects of statins on cancer development and progression.

Statins are not associated with a reduced risk of pancreatic cancer at the population level, when taken at low doses for managing hypercholesterolemia: evidence from a meta-analysis of 12 studies

OBJECTIVES

Recent experimental research on a class of pharmacological agents that reduce plasma cholesterol, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), has shown promise in pancreatic cancer chemoprevention. While the mechanism remains unclear, several epidemiological studies have also evaluated the relationship between statin use and pancreatic cancer. Our aim was to examine the strength of this association through a detailed meta-analysis of the studies published on the subject in peer-reviewed literature.

METHODS

A comprehensive search for articles published up to December 2007 was performed, reviews of each study were conducted, and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random-effects model.

RESULTS

Twelve studies (3 randomized placebo-controlled trials [RCTs], 4 cohort, and 5 case-control studies) contributed to the analysis. The studies were grouped on the basis of study design, and separate meta-analyses were conducted. There was no evidence of an association between statin use and pancreatic cancer among either the RCTs (RR 0.99, 95% CI 0.44-2.21) or the observational studies (RR 0.86, 95% CI 0.60-1.24). Similarly, we found no evidence of publication bias. However, a high heterogeneity was detected among the observational studies.

CONCLUSION

Despite the chemopreventive potential of statins demonstrated in experimental studies, our results do not support the hypothesis that these agents reduce the risk of pancreatic cancer at the population level, when taken at low doses for managing hypercholesterolemia.

Statin use and prostate cancer risk in a large population-based setting

BACKGROUND

Statins are a commonly used cholesterol-lowering drug, which also have the potential to affect cancer risk and progression. Results from previous studies offer mixed conclusions.

METHODS

To evaluate the relation between statin use and prostate cancer risk, we conducted a retrospective cohort study during 1 January 1990 to 31 August 2005 among men 45-79 years receiving care within Group Health, an integrated healthcare delivery system. Information on statin use and covariates were obtained from health plan databases. We identified incident prostate cancer cases through the Surveillance, Epidemiology, and End Results cancer registry. We used Cox proportional hazards models to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for prostate cancer among statin users compared to non-users.

RESULTS

Among 83,372 men studied, median follow-up time was 5.7 years and 2,532 prostate cancer cases were identified. About 14.4% used statins over the study period and median duration of use was 3.3 years. Compared to non-users, hydrophobic statin users had a reduced risk of prostate cancer (HR = 0.79; 95% CI, 0.66-0.94), and results are suggestive of a reduced risk among ever users of statins (HR = 0.88; 95% CI, 0.76-1.02) and hydrophilic statin users (HR = 0.67; 95% CI, 0.33-1.34). There was no trend in risk by duration of statin use, and no association between statin use and cancer aggressiveness, stage, or grade.

CONCLUSION

Overall, this study does not support an associated between statin use and prostate cancer but a reduced risk cannot be ruled out.

Breast cancer growth prevention by statins

Statins are cholesterol-lowering drugs with pleiotropic activities including inhibition of isoprenylation reactions and reduction of signals driving cell proliferation and survival responses. The objectives of this study were to examine the effects of statins on breast cancer cells, both in vitro and in vivo, and to begin to determine their mechanism of action. We evaluated the effects of statins on breast cancer cell growth, phosphoprotein signaling intermediates, survival/apoptosis regulators, cell cycle regulators, and activated transcription factors. We also examined the in vivo effect of statin administration in a mouse ErbB2(+) breast cancer model. Only lipophilic statins had direct anticancer activity in vitro. Breast cancer cells with activated Ras or ErbB2 pathways seemed to be more sensitive than those overexpressing estrogen receptor, and this correlated with endogenous levels of activated nuclear factor kappaB (NF-kappaB). Key intermediates regulating cell survival by NF-kappaB activation, as well as cell proliferation by the mitogen activated protein kinase cascade, were among the earliest phosphoproteins influenced by statin treatment. These early effects were followed by declines in activator protein-1 and NF-kappaB activation and concordant changes in other mediators of proliferation and apoptosis. In vivo results showed that oral dosing of statins significantly inhibited the growth of a mouse mammary carcinoma. Lipophilic statins can exert direct anticancer activity in vitro by reducing proliferation and survival signals in susceptible breast cancer phenotypes. Tumor growth inhibition in vivo using a clinically relevant statin dose also seems to be associated with reduced tumor cell proliferation and survival. These findings provide supporting rationale for future statin trials in breast cancer patients.

Statin drugs and risk of advanced prostate cancer

BACKGROUND

Statins are commonly used cholesterol-lowering drugs that have proapoptotic and antimetastatic activities that could affect cancer risk or progression. Results from previous epidemiologic studies of the association between statin use and cancer have been inconsistent. We investigated the association of statin use with total and advanced prostate cancer, the latter being the most important endpoint to prevent.

METHODS

We analyzed data from an ongoing prospective cohort study of 34,989 US male health professionals who were cancer free in 1990 and were followed to 2002. Participants reported their use of cholesterol-lowering drugs on biennial questionnaires. Prostate cancer diagnosis was confirmed by medical record review. Multivariable-adjusted relative risks (RRs) were estimated from Cox proportional hazards regression models. Statistical tests were two-sided.

RESULTS

During 376,939 person-years of follow-up, we ascertained 2579 prostate cancer cases, 316 of which were advanced (regionally invasive, metastatic, or fatal). The age-standardized incidence rates of advanced prostate cancer were 38 and 89 per 100,000 person-years in current statin users and in past or never users, respectively. The multivariable-adjusted relative risk of advanced disease was 0.51 (95% confidence interval [CI] = 0.30 to 0.86) and of metastatic or fatal disease was 0.39 (95% CI = 0.19 to 0.77) for current statin use compared with no current use. The associations remained after adjusting for prostate-specific antigen screening history (advanced disease: RR = 0.57, 95% CI = 0.30 to 1.11; metastatic or fatal disease: RR = 0.35, 95% CI = 0.14 to 0.92). Risk of advanced disease was lower with longer statin use (P(trend) = .003); compared with never use, the relative risk for less than 5 years of use was 0.60 (95% CI = 0.35 to 1.03) and for 5 or more years of use was 0.26 (95% CI = 0.08 to 0.83). We found no association between statin use and risk of total prostate cancer (RR = 0.96, 95% CI = 0.85 to 1.09).

CONCLUSIONS

In this cohort of male health professionals, use of statin drugs was not associated with risk of prostate cancer overall but was associated with a reduced risk of advanced (especially metastatic or fatal) prostate cancer.

Drug Insight: statins and gastrointestinal cancer

Statins are popular lipid-lowering drugs that have had a great impact on the primary and secondary prevention of cardiovascular diseases. Basic and clinical research have also revealed that statins have biologic activities that go beyond lipid lowering, and suggest that they might have other therapeutic benefits. Perhaps the most exciting of these additional biologic effects is the finding that statins can exert an anticancer effect on cultured cancer cells, and in animal models. Clinical studies of statins for the treatment and prevention of cancer have, however, produced conflicting results. This review critically evaluates the current body of literature on the role of statins in the treatment and prevention of gastrointestinal cancers, with particular focus on clinical and observational studies.

Use of Statins and Breast Cancer: A Meta-Analysis of Seven Randomized Clinical Trials and Nine Observational Studies

Purpose

A growing body of evidence suggests that statins may have chemopreventive potential against breast cancer. Laboratory studies demonstrate that statins induce apoptosis and reduce cell invasiveness in various cell lines, including breast carcinoma cells. However, the clinical relevance of these data remains unclear. The nonconclusive nature of the epidemiologic data prompted us to conduct a detailed meta-analysis of the studies published on the subject in peer-reviewed literature.

Patients and Methods

A comprehensive search for articles published up until 2005 was performed; reviews of each study were conducted; and data were abstracted. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% CIs were calculated using the random and the fixed-effects models. Subgroup and sensitivity analyses were also performed.

Results

Seven large randomized trials and nine observational studies (five case-control and four cohort studies) contributed to the analysis. We found no evidence of publication bias or heterogeneity among the studies. Statin use did not significantly affect breast cancer risk (fixed effects model: RR = 1.03; 95% CI, 0.93 to 1.14; random effects model: RR = 1.02; 95% CI, 0.89 to 1.18). When the analyses were stratified into subgroups, there was no evidence that study design substantially influenced the estimate of effects. Furthermore, the sensitivity analysis confirmed the stability of our results.

Conclusion

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.

Therapy insight: Potential of statins for cancer chemoprevention and therapy

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, are commonly prescribed medications that lower serum cholesterol and decrease cardiac morbidity and mortality. These agents inhibit the rate-limiting step of the mevalonate pathway, an effect that influences cholesterol homeostasis and other diverse cellular functions. Preclinical data suggest statins have pleiotropic antineoplastic effects in a variety of tumors, but clinical studies have provided conflicting data regarding whether statins may increase or decrease the risk of cancer. Abnormal cholesterol metabolism in cancer is poorly understood but should be considered when evaluating the antineoplastic effects of statins. Emerging evidence suggests that atherosclerosis and cancer have similar underlying molecular mechanisms, both having lipid abnormalities and a pro-inflammatory phenotype. Like nonsteroidal anti-inflammatory agents, statins target lipid metabolism, have significant anti-inflammatory effects, and can influence cardiovascular mortality. Recent studies show that statins may have chemopreventive effects and may complement cytotoxic chemotherapy or radiotherapy as a biologic response modifier in established cancer, but current data do not support their use as monotherapy. The preclinical data supporting anticancer activity, their additional health benefits, and the safety and relative low cost of statins compared to other 'targeted' agents currently under development all favor conducting prospective clinical trials of these drugs in cancer chemoprevention and therapy.

Cancer risk among statin users: a population-based cohort study

Hydroxymethylglutaryl-CoA reductase inhibitors (statins) have been linked with potential chemopreventive effects; however, the data are conflicting. We conducted a population-based cohort study using data from the Prescription Database of North Jutland County and the Danish Cancer Registry for the period 1989-2002. In a study population of 334,754 county residents, we compared overall and site-specific cancer incidence among 12,251 statin users (> or =2 prescriptions) with cancer incidence among nonusers and users of other lipid-lowering drugs (n = 1,257). Statistical analyses were based on age-standardization and Poisson regression analysis, adjusting for age, gender, calendar period and use of NSAIDs, hormone replacement therapy and cardiovascular drugs. We identified 398 cancer cases among statin users during a mean follow-up period of 3.3 years (range 0-14 years). The age- and gender-standardized incidence rates of cancer overall were 596 per 100,000 person-years among statin users, 645 per 100,000 person-years among nonusers and 795 per 100,000 person-years among users of other lipid-lowering drugs. Adjusted rate ratios for cancer overall among statin users were 0.86 (95% CI, 0.78-0.95) compared to nonusers and 0.73 (95% CI, 0.55-0.98) compared to users of other lipid-lowering drugs. No significantly increased or decreased rate ratios were observed for any of the studied site-specific cancers (liver, colorectum, lung, breast, prostate, female genital organs and lymphatic and haematopoietic tissue), but most estimates tended to be less than 1.0. Stratification by duration of follow-up or number of prescriptions revealed no clear trends. In summary, individuals prescribed statins experienced a slightly reduced cancer incidence compared to population controls of nonusers and users of other lipid-lowering drugs. Larger and longer-term studies are needed to determine the potentially protective effect of statin use on cancer development.

The association between 3-hydroxy-3-methylglutaryl conenzyme A inhibitor use and breast carcinoma risk among postmenopausal women: a case-control study

BACKGROUND

Statin use has increased dramatically in the U.S. in the past decade. Animal and mechanistic studies suggested that statins may have an inhibitory effect on cancer proliferation, including breast carcinoma. However, statins have been found to be carcinogenic in rodents and one clinical trial found an excess of breast carcinoma cases in the treatment group.

METHODS

The current study assessed whether the use of statins altered the risk of breast carcinoma in older women. The population-based, case-control study comprised female residents from three western Washington State counties. Cases included 975 women identified from the Cancer Surveillance System who were diagnosed with primary invasive breast carcinoma between 1997-1999, whose names appeared on a list of Social Security recipients provided by the Centers for Medicare and Medicaid Services. The cases were ages 65-79 years at the time of diagnosis. The comparison group was comprised of 1007 women without breast carcinoma who were randomly selected from the same list of Social Security recipients. Information pertaining to statin use, medical history, and health behaviors was ascertained through an in-person interview.

RESULTS

Compared with nonusers, women who were currently using statins or had ever used statins were not found to be at an increased risk for breast carcinoma (odds ratios [OR] = 0.9; 95% confidence interval [95% CI], 0.7-1.2). There was some indication that long-term statin use (> 5 years) was related to a slight decrease in breast carcinoma risk (OR = 0.7; 95% CI, 0.4-1.0).

CONCLUSIONS

The results of the current study provided some degree of reassurance to the increasing numbers of women using statins that such use is not associated with an increased risk of breast carcinoma. Although the data gave some support to a reduced risk of breast carcinoma among long-term users of statins, further research is needed to confirm this association.