The associations between statin use and prostate cancer screening, prostate size, high-grade prostatic intraepithelial neoplasia (PIN), and prostate cancer

Association Between Statin Exposure and Incidence and Prognosis of Prostate Cancer: A Meta-analysis Based on Observational Studies

It is widely thought that statins have huge therapeutic potential against prostate cancer (PCA). This study aimed to investigate the effect of statin exposure on PCA incidence and prognosis. PubMed, Web of Science, Embase, and Cochrane databases were searched for observational studies on the association between statin exposure and PCA from inception until July 2022. The primary endpoints were the incidence of PCA and the survival rate. A total of 21 studies were included in this meta-analysis. The pooled estimates showed that exposure to hydrophilic statins was not associated with the incidence of PCA (odds ratio [OR]=0.94, 95% CI=0.88-1.01, P =0.075), while the incidence of PCA was significantly decreased in populations exposed to lipophilic statins compared with the nonexposed group (OR=0.94, 95% CI=0.90-0.98, P =0.001), mainly in Western countries (OR=0.94, 95% CI=0.91-0.98, P =0.006). Subgroup analysis showed that simvastatin (OR=0.83, 95% CI=0.71-0.97, P =0.016) effectively reduced the incidence of PCA. The prognosis of PCA in patients exposed to both hydrophilic (hazard ratio [HR]=0.57, 95% CI=0.49-0.66, P <0.001) and lipophilic (HR=0.65, 95% CI=0.58-0.73, P <0.001) statins were better than in the nonexposed group, and this improvement was more significant in the East than in Western countries. This study demonstrates that statins can reduce the incidence of PCA and improve prognosis, and are affected by population region and statin properties (hydrophilic and lipophilic).

Association of Statin Use with the Risk of Incident Prostate Cancer: A Meta-Analysis and Systematic Review

Background

With the growth and aging of population, the incidence of prostate cancer will increase year by year, which is bound to bring greater economic burden to the society. There has been greater interest in the anticancer effects of statin in recent years. It is controversial whether statin use is associated with the risk of prostate cancer (PCa). Thus, we conducted a meta-analysis and systematic review to explore the effects of statin use and their duration and cumulative dose on the overall incidence of PCa.

Method

The study was conducted according to the latest guidelines for PRISMA 2020. We searched PubMed and other databases for studies about the association of statin use with the risk of incident prostate cancer between January 1, 1990, and April 11, 2022. Two independent researchers extracted data and evaluated the quality of the studies. R x64 4.1.2 and random-effects model were used for data statistics. Relative risk (RR) and odds ratio (OR) effective values with a 95% confidence interval (95% CI) were used to assess the main results.

Results

The results of 6 RCT and 26 cohort studies showed that statins did not significantly associate with the incidence of PCa (RR = 0.94, 95% CI: 0.82-1.08). The similar results were obtained from 9 case-control studies (OR = 1.03, 95% CI: 0.99-1.07). However, statins were associated with a lower risk of Pca (RR = 0.44, 95% CI: 0.28-0.70) when the cumulative defined daily dose (cDDD) was high. Using statins for more than five years could be associated with a reduced incidence of Pca (RR = 0.47, 95% CI: 0.23-0.97). There was a significant heterogeneity in these studies (RCT and cohort study: I ² = 98%, P < 0.01; case-control study: I ² = 72%, P < 0.01).

Conclusion

We concluded that statins had a neutral association with the overall risk of PCa. High cDDD and long duration were associated with a lower risk of PCa.

Inhibition of Scavenger Receptor Class B Type 1 (SR-B1) Expression and Activity as a Potential Novel Target to Disrupt Cholesterol Availability in Castration-Resistant Prostate Cancer

There have been several studies that have linked elevated scavenger receptor class b type 1 (SR-B1) expression and activity to the development and progression of castration-resistant prostate cancer (CRPC). SR-B1 facilitates the influx of cholesterol to the cell from lipoproteins in systemic circulation. This influx of cholesterol may be important for many cellular functions, including the synthesis of androgens. Castration-resistant prostate cancer tumors can synthesize androgens de novo to supplement the loss of exogenous sources often induced by androgen deprivation therapy. Silencing of SR-B1 may impact the ability of prostate cancer cells, particularly those of the castration-resistant state, to maintain the intracellular supply of androgens by removing a supply of cholesterol. SR-B1 expression is elevated in CRPC models and has been linked to poor survival of patients. The overarching belief has been that cholesterol modulation, through either synthesis or uptake inhibition, will impact essential signaling processes, impeding the proliferation of prostate cancer. The reduction in cellular cholesterol availability can impede prostate cancer proliferation through both decreased steroid synthesis and steroid-independent mechanisms, providing a potential therapeutic target for the treatment of prostate cancer. In this article, we discuss and highlight the work on SR-B1 as a potential novel drug target for CRPC management.

Effect of Statins on the Risk of Different Stages of Prostate Cancer: A Meta-Analysis

INTRODUCTION

The aim of this article was to investigate the relationship between statins and the risk of different stages or grades of prostate cancer.

METHODS

A comprehensive literature search was performed for articles published until December 18, 2020, on the PubMed, Embase, and the Cochrane Library databases. The pooled relative risk (RR) and 95% confidence interval (CI) were then analyzed using the STATA.16.0 software.

RESULTS

A total of 588,055 patients from 14 studies were included in the analysis. We found that the use of statins expressed a significant correlation with a lower risk of advanced prostate cancer (RR = 0.81, 95% CI: 0.73-0.91; RR = 0.86, 95% CI: 0.75-0.99, respectively). However, no evidence suggested that the use of statins was beneficial for the prevention of localized prostate cancer incidence. Similarly, the pooled results also revealed no association between the use of statins and the risk of high-grade and low-grade prostate cancer.

CONCLUSION

It has been found that the use of statins is associated with a lower risk of advanced prostate cancer but was not related to the risk of localized, low-grade, or high-grade prostate cancer.

Prostate cancer incidence and mortality among men using statins and non-statin lipid-lowering medications

BACKGROUND

Statins have demonstrated protection against aggressive/late-stage and/or lethal prostate cancer (PC), but prior studies are limited by small populations, short follow-up and unequal health-care access. Research has not demonstrated that non-statin lipid-lowering medications (NSLLMs) provide a similar benefit, which would support a cholesterol-based mechanism. We sought to rigorously test the hypothesis that cholesterol-lowering drugs affect PC incidence and severity.

METHODS

A retrospective cohort study was conducted by abstracting prescription and health service records for 249,986 Saskatchewan men aged ≥40 years between January 1, 1990 and December 31, 2014 and comparing first-time statin and NSLLM users with age-matched non-users and glaucoma medication (GM) users for PC incidence, metastases at diagnosis and PC mortality using Cox proportional hazards regression.

RESULTS

In comparing statin users to non-users, a weak association was detected with increased PC incidence (hazard ratio [HR] 1.07, 95% confidence interval [CI]: 1.02-1.12) that disappeared when compared with GM users. Substantial protective associations were observed between statin use and metastatic PC and PC mortality (HRs 0.69, 95% CI: 0.61-0.79 and 0.73, 95% CI: 0.66-0.81, respectively), which were stronger when compared with GM use (HRs 0.52, 95% CI: 0.40-0.68 and 0.51, 95% CI: 0.41-0.63, respectively). Similar associations were found for NSLLM versus GM for metastatic PC (HR 0.57, 95% CI: 0.41-0.79) and PC mortality (HR 0.66, 95% CI: 0.51-0.85).

CONCLUSIONS

Our analyses provide one of the more comprehensive findings to date that statins may reduce risk of metastatic PC and PC mortality, and the first to demonstrate that NSLLM have similar effects, supporting a cholesterol-based mechanism.

Statin use linked with a decrease in the conversion from high-grade prostatic intraepithelial neoplasia (HGPIN) to prostate cancer

The roles of obesity, metabolic dysregulation and systemic inflammation to advance prostate carcinogenesis are unclear. This study investigates metabolic and inflammatory factors in the transition from high-grade prostatic intraepithelial neoplasia (HGPIN) to prostate cancer (PC). We prospectively followed 160 men diagnosed with HGPIN at biopsy and therefore at high-risk and clinically monitored for PC. Analyses investigated body mass index (BMI), waist circumference, waist-hip ratio (WHR), height, fat mass, lean mass percent body fat, NSAIDs, statins, metformin, diabetes, hypertension, hypercholesterolemia representing metabolic dysregulation on the risk of a PC diagnosis during follow-up. Systemic inflammation was estimated through measurement of 13 plasma cytokine levels. Statin use was significantly linked with overall PC at follow-up [odds ratio (OR) = 0.45, (0.23, 0.91), P = 0.03], with a somewhat stronger link with high-grade [OR = 0.39, (0.15, 1.04), P = 0.06] PC compared with low-grade PC [OR = 0.50, (0.23, 1.12), P = 0.09]. Non-statin cholesterol-lowering medications, BMI, WHR, diabetes, hypertension and percent body fat were not significantly associated with PC. Although blood IL-12p70, IL-2 and IL-1β levels were significantly lower among statin users, inflammatory markers were not significantly linked with PC and did not explain the observed relationship between statins and lower PC risk. In summary, this prospective study of HGPIN patients at high risk for PC finds that statin use was significantly associated with reduced risk of PC detection at follow-up. Systemic markers of inflammation did not mediate this association, suggesting that statins affect PC progression through alternative pathways.

Effect of statins type on incident prostate cancer risk: a meta-analysis and systematic review

The aim of this study is to investigate the effect of statins type or even when grouping statins by hydrophilic or hydrophobic nature on prostate cancer risk. A literature search was performed without language restrictions using the databases of PubMed (1984.1-2015.3), MEDLINE (1984.1-2015.3), and EMBASE (1990.1-2015.3). Two independent reviewers appraised eligible studies and extracted data. Weighted averages were reported as relative risk (RR) with 95% confidence intervals (CI). Statistic heterogeneity scores were assessed with the standard Cochran's Q-test and I2 statistic. Publication bias was detected using the Begg's and Egger's tests. All statistical analyses were conducted by STATA version 10. Finally, fourteen studies were included in the meta-analysis. Both hydrophilic and hydrophobic statins showed no association with incidence of prostate cancer (RR = 1.00, 95% CI: 0.82-1.17; RR = 0.90, 95% CI: 0.73-1.08, respectively). Meanwhile, the risk of prostate cancer was not reduced in simvastatin (RR = 0.89, 95% CI: 0.72-1.05), pravastatin (RR = 1.02, 95% CI: 0.94-1.11), atorvastatin (RR = 0.89, 95% CI: 0.76-1.02), fluvastatin (RR = 0.99, 95% CI: 0.97-1.01), or lovastatin users (RR = 0.94, 95% CI: 0.79-1.08). The funnel plot showed that there was no publication bias. The results showed that statins had a neutral effect on prostate cancer risk; hydrophilic and hydrophobic statins as well as any subtype of statins did not affect the risk of prostate cancer.

Current and Emerging Uses of Statins in Clinical Therapeutics: A Review

Statins, a class of cholesterol-lowering medications that inhibit 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, are commonly administered to treat atherosclerotic cardiovascular disease. Statin use may expand considerably given its potential for treating an array of cholesterol-independent diseases. However, the lack of conclusive evidence supporting these emerging therapeutic uses of statins brings to the fore a number of unanswered questions including uncertainties regarding patient-to-patient variability in response to statins, the most appropriate statin to be used for the desired effect, and the efficacy of statins in treating cholesterol-independent diseases. In this review, the adverse effects, costs, and drug–drug and drug–food interactions associated with statin use are presented. Furthermore, we discuss the pleiotropic effects associated with statins with regard to the onset and progression of autoimmune and inflammatory diseases, cancer, neurodegenerative disorders, strokes, bacterial infections, and human immunodeficiency virus. Understanding these issues will improve the prognosis of patients who are administered statins and potentially expand our ability to treat a wide variety of diseases.

The current evidence on statin use and prostate cancer prevention: are we there yet?

An increasing amount of data supports an inverse association between statin use and cancer risk. The findings for prostate cancer, particularly advanced disease, are the most promising of all cancers studied. Use of these agents seems to also be associated with improved prostate- cancer-specific survival, particularly in men undergoing radiotherapy, suggesting usefulness of statins in secondary and tertiary prevention. Some study results might be influenced by increased PSA screening and health-conscious behaviour in statin users but these factors are unlikely to completely account for observed beneficial effects. The epidemiological evidence is supported by preclinical studies that show that statins directly inhibit prostate cancer development and progression in cell-based and animal-based models. The antineoplastic effect of statins might arise from a number of cholesterol-mediated and non-cholesterol-mediated mechanisms that affect pathways essential for cancer formation and progression. Understanding these mechanisms is instrumental in drug discovery research for the development of future prostate cancer therapeutics, as well as in designing clinical trials to test a role for statins in prostate cancer prevention. Currently, sufficient data are lacking to support the use of statins for the primary prevention of prostate cancer and further research is clearly warranted. Secondary and tertiary prevention trials in men who have been diagnosed with prostate cancer might soon be performed.

Statin Use in Prostate Cancer: An Update

3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, known as statins, are commonly prescribed for the treatment of hypercholesterolemia and cardiovascular disease. A systematic review was conducted using the keywords “statin and prostate cancer” within the title search engines including PubMed, Web of Science, and the Cochrane Library for relevant research work published between 2004 and December 2015. Although still premature, accumulating clinical evidence suggests that statin use may be beneficial in the prevention and/or treatment of prostate cancer. These human studies consist of meta-analyses of secondary endpoints obtained from randomized, controlled cardiovascular disease clinical trials of statins, patient database, observational studies, and a few, small case–control studies, directly addressing statin use on prostate cancer pathology and recurrence. This review summarizes and discusses the recent clinical literature on statins and prostate cancer with a recommendation to move forward with randomized, placebo-controlled clinical trials, investigating the use of statins. Additional preclinical testing of statins on prostate cancer cell lines and in vivo models is needed to elucidate pathways and determine its efficacy for prevention and/or treatment of prostate cancer, more specifically, the difference in the effectiveness of lipophilic versus hydrophilic statins in prostate cancer.

LDL-lowering therapy and the risk of prostate cancer: a meta-analysis of 6 randomized controlled trials and 36 observational studies

The role of statins in preventing prostate cancer is currently a controversial issue. The aim of this review is to investigate the effects of statins use on prostate cancer risk. Electronic databases (the Cochrane Library, PubMed, Medline, Embase, Web of Science, and ClinicalTrials.gov) were searched systematically up to April, 2015. Weighted averages were reported as relative risk (RR) with 95% confidence intervals (CIs). Statistic heterogeneity scores were assessed with the standard Cochran’s Q test and I² statistic. The pooled estimates of randomized controlled trials (RCTs) and retrospective studies suggest that statins have a neutral effect on total prostate cancer (RR = 1·02, 95% CI: 0·90–1·14; and RR = 0·91, 95% CI: 0·79–1·02, respectively). This research provides no evidence to suggest that the use of statins for cholesterol lowering is beneficial for the prevention of low-grade or localized prostate cancer, although a plausible association between statins use and the reduction risk of advanced (RR = 0·87, 95% CI: 0·82–0·91) or high-grade prostate cancer (RR = 0·83, 95% CI: 0·66–0·99) is observed. Furthermore, it shows that prostate cancer risk does not statistically significant benefit from long-term statins use.

Statin use and risk of prostate cancer: Results from the Southern Community Cohort Study

BACKGROUND

Epidemiologic studies suggest that statin use may be inversely associated with risk of prostate cancer, but prior studies have focused predominantly on non-Hispanic white populations.

METHODS

We evaluated the association between statin use and prostate cancer risk in the Southern Community Cohort Study (SCCS). Study participants were 32,091 men aged 40-79 at baseline, 67% of whom were non-Hispanic black. Between study enrollment (2002-2009) and December 31, 2010, 570 prostate cancer cases were diagnosed, including 324 low-grade cancers (Gleason score <7 or Gleason pattern 3 + 4) and 107 high-grade cancers (Gleason score >7 or Gleason pattern 4 + 3). Analyses of overall prostate cancer were conducted using Cox regression and analyses of grade-specific cancer were conducted using competing risks models.

RESULTS

Ten percent of non-Hispanic black men and 22% of non-Hispanic white men reported use of statins at study enrollment. As compared to non-use, statin use was associated with a non-significant 14% lower risk of prostate cancer in multivariable models (Hazard Ratio [HR]:0.86; 95% Confidence Interval [CI]: 0.63-1.18). This association was stronger for high-grade cancer (HR: 0.62; 95%CI: 0.30, 1.28) than low-grade cancer (HR:0.98; 95%CI: 0.65-1.48). Results were similar by race/ethnicity (p-interaction: 0.41) and did not vary by history of prostate-specific antigen [PSA] screening (p-interaction: 0.65).

CONCLUSIONS

Results suggest no strong association between statin use and prostate cancer risk overall, and further suggest that if a modest protective effect does exist, it does not vary by race/ethnicity and may be restricted to high-grade tumors, although power to detect differences by subgroup was limited.

Statin use after radical prostatectomy reduces biochemical recurrence in men with prostate cancer

BACKGROUND

The impact of statin use on biochemical recurrence (BCR) of prostate cancer after radical prostatectomy (RP) is controversial.

METHODS

In 2,137 consecutive RP patients between 1998 and 2011 at Asan Medical Center, we aimed to assess the presence and impact of statin use according to types (hydrophilic vs. hydrophobic), dose equivalents (DEs), and postoperative duration of usage (<18, 18-36, >36 months). Between non-users and preoperative or postoperative users, clinicopathological characteristics, and impact of statin use on BCR were analyzed using Cox proportional hazards model. Mean (range) follow-up was 39.4 (8-183) months.

RESULTS

Compared to non-users, preoperative users had lower PSA (5.8 vs. 7 ng/ml), but the rates of organ confined disease, pathologic Gleason score (GS) or positive surgical margin (PSM) were not different. After adjusting for pathologic stage, postoperative statin use was associated with a higher BCR-free survival. In multivariate analysis, ≤36 months' statin use independently decreased the risk of BCR along with PSA, pathologic GS, pathologic stage, and PSM. Risk reduction was observed especially in patients with pathologic GS ≥ 7 (HR 0.27, 95% CI 0.13-0.59, P = 0.001), NSM disease (HR 0.18, 95% CI 0.05-0.63, P = 0.007), or PSA ≥ 10.0 ng/ml (HR 0.30, 95% CI 0.11-0.81, P = 0.018). Increasing duration of use nullified the effect. Preoperative statin use did not demonstrate significant risk reduction for BCR in any of the stratified multivariate models.

CONCLUSION

In Korean men undergoing RP, preoperative statin use was not associated with different pathologic outcome. However, postoperative statin use until 36 months decreased the risk of BCR independently especially in patients with high-risk disease.

Effects of 14 frequently used drugs on prostate-specific antigen expression in prostate cancer LNCaP cells

Prostate cancer occurs more frequently among older males and such elderly individuals often have chronic underlying disorders for which various drugs are administered for treatment. The levels of prostate-specific antigen (PSA), a widely used prostate cancer marker, are influenced by a number of drugs, such as non-steroidal anti-inflammatory drugs and statins. In the present study, the drugs prescribed to patients on a repeat prescription collected at the pharmacy of the Gifu Pharmaceutical University (Gifu, Japan) were examined for their effects on the levels of PSA expression in prostate cancer LNCaP cells. Among the 14 drugs investigated, betamethasone, an agonist of the glucocorticoid receptor, was found to increase the levels of PSA mRNA expression in the LNCaP cells. This betamethasone-induced expression was mediated, at least in part, through androgen receptor (AR) transcriptional activation. Dexamethasone, a typical agonist of the glucocorticoid receptor, was also found to stimulate the AR transcriptional activity, however, to a lesser extent than betamethasone. Therefore, it would be interesting to examine in future studies whether the serum PSA levels in prostate cancer patients are influenced by betamethasone.

Simvastatin reduces melanoma progression in a murine model

Statins are a class of drugs that inhibit the rate-limiting step in the cholesterol biosynthetic pathway and show an anticancer effect, probably through the inhibition of cell proliferation. To date, the exact mechanism of cancer cell growth arrest induced by statins is not known. We report that simvastatin is able to induce apoptosis in melanoma cells but not in normal cells and also able to contrast the growth of tumor in an experimental melanoma murine model. We observed a delay in the tumor development in almost the 50% of the simvastatin administered animals and a strong reduction of the tumor volume with a differences of ~150% compared to the controls. Also the survival rate was significantly higher in mice that received the drug with a survival increase of ~130% compared to the controls. The tumor growth reduction in mice was supported by the results of cell migration assay, confirming that simvastatin clearly reduced cell migration. Moreover, simvastatin induced a strong downregulation of NonO gene expression, an important growth factor involved in the splicing regulation. This result could explain the decrease of melanoma cells proliferation, suggesting a possible action mechanism. The results derived from our experiments may sustain the many reports on the anticancer inhibitory property of statins and encourage new studies on this drug for a possible use in therapy, probably in combination with conventional chemotherapy.

Diabetes and prostate cancer screening in black and white men

PURPOSE

Prior studies conducted primarily among white men find a reduced risk of prostate cancer associated with time since developing diabetes. While biologic explanations are plausible, the association may in part arise from more frequent prostate cancer screening among those with a diabetes diagnosis. The purpose of the present study was to investigate the association between diabetes and prostate cancer screening.

METHODS

We examined differences in prostate cancer screening (prostate-specific antigen and/or digital rectal examination) testing practices after a diabetes diagnosis among lower-income persons living in the southeastern United States and enrolled in the Southern Community Cohort Study between 2002 and 2009. Baseline in-person interviews collected information on history of diabetes and prostate cancer screening from 18,809 black and 6,404 white men aged 40-79 years.

RESULTS

After adjustment for confounding, diabetic black [odds ratio (OR) 1.12, 95 % confidence interval (CI) 1.01-1.25] and white (OR 1.25, 95 % CI 1.03-1.51) men were more likely to undergo recent prostate cancer screening compared to non-diabetic men of the same race. The increased risk for prostate cancer screening, however, occurred primarily within the first 12 months after diabetes diagnosis.

CONCLUSIONS

Our results suggest that a diabetes diagnosis modestly increases the likelihood of having a prostate cancer screening test for both black and white men. The prevalence of screening was higher nearer to the time of diabetes diagnosis, which may contribute to an early increase in prostate cancer detection followed by lower prostate cancer detection after an extended time.

New players for advanced prostate cancer and the rationalisation of insulin-sensitising medication

Obesity and type 2 diabetes are recognised risk factors for the development of some cancers and, increasingly, predict more aggressive disease, treatment failure, and cancer-specific mortality. Many factors may contribute to this clinical observation. Hyperinsulinaemia, dyslipidaemia, hypoxia, ER stress, and inflammation associated with expanded adipose tissue are thought to be among the main culprits driving malignant growth and cancer advancement. This observation has led to the proposal of the potential utility of "old players" for the treatment of type 2 diabetes and metabolic syndrome as new cancer adjuvant therapeutics. Androgen-regulated pathways drive proliferation, differentiation, and survival of benign and malignant prostate tissue. Androgen deprivation therapy (ADT) exploits this dependence to systemically treat advanced prostate cancer resulting in anticancer response and improvement of cancer symptoms. However, the initial therapeutic response from ADT eventually progresses to castrate resistant prostate cancer (CRPC) which is currently incurable. ADT rapidly induces hyperinsulinaemia which is associated with more rapid treatment failure. We discuss current observations of cancer in the context of obesity, diabetes, and insulin-lowering medication. We provide an update on current treatments for advanced prostate cancer and discuss whether metabolic dysfunction, developed during ADT, provides a unique therapeutic window for rapid translation of insulin-sensitising medication as combination therapy with antiandrogen targeting agents for the management of advanced prostate cancer.

Statin use and risk of prostate cancer: a meta-analysis of observational studies

BACKGROUND

Emerging evidence suggests that statins may decrease the risk of cancers. However, available evidence on prostate cancer (PCa) is conflicting. We therefore examined the association between statin use and risk of PCa by conducting a detailed meta-analysis of all observational studies published regarding this subject.

METHODS

Literature search in PubMed database was undertaken through February 2012 looking for observational studies evaluating the association between statin use and risk of PCa. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using random-effects model (DerSimonian and Laird method). Subgroup analyses, sensitivity analysis and cumulative meta-analysis were also performed.

RESULTS

A total of 27 (15 cohort and 12 case-control) studies contributed to the analysis. There was heterogeneity among the studies but no publication bias. Statin use significantly reduced the risk of both total PCa by 7% (RR 0.93, 95% CI 0.87-0.99, p = 0.03) and clinically important advanced PCa by 20% (RR 0.80, 95% CI 0.70-0.90, p<0.001). Long-term statin use did not significantly affect the risk of total PCa (RR 0.94, 95% CI 0.84-1.05, p = 0.31). Stratification by study design did not substantially influence the RR. Furthermore, sensitivity analysis confirmed the stability of results. Cumulative meta-analysis showed a change in trend of reporting risk from positive to negative in statin users between 1993 and 2011.

CONCLUSIONS

Our meta-analysis provides evidence supporting the hypothesis that statins reduce the risk of both total PCa and clinically important advanced PCa. Further research is needed to confirm these findings and to identify the underlying biological mechanisms.

Cholesterol and prostate cancer

Prostate cancer risk can be modified by environmental factors, however the molecular mechanisms affecting susceptibility to this disease are not well understood. As a result of a series of recently published studies, the steroidal lipid, cholesterol, has emerged as a clinically relevant therapeutic target in prostate cancer. This review summarizes the findings from human studies as well as animal and cell biology models, which suggest that high circulating cholesterol increases risk of aggressive prostate cancer, while cholesterol lowering strategies may confer protective benefit. Relevant molecular processes that have been experimentally tested and might explain these associations are described. We suggest that these promising results now could be applied prospectively to attempt to lower risk of prostate cancer in select populations.

Differential effects of pravastatin and simvastatin on the growth of tumor cells from different organ sites

3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) inhibitors, commonly known as statins, may possess cancer preventive and therapeutic properties. Statins are effective suppressors of cholesterol synthesis with a well-established risk-benefit ratio in cardiovascular disease prevention. Mechanistically, targeting HMGCR activity primarily influences cholesterol biosynthesis and prenylation of signaling proteins. Pravastatin is a hydrophilic statin that is selectively taken up by a sodium-independent organic anion transporter protein-1B1 (OATP1B1) exclusively expressed in liver. Simvastatin is a hydrophobic statin that enters cells by other mechanisms. Poorly-differentiated and well-differentiated cancer cell lines were selected from various tissues and examined for their response to these two statins. Simvastatin inhibited the growth of most tumor cell lines more effectively than pravastatin in a dose dependent manner. Poorly-differentiated cancer cells were generally more responsive to simvastatin than well-differentiated cancer cells, and the levels of HMGCR expression did not consistently correlate with response to statin treatment. Pravastatin had a significant effect on normal hepatocytes due to facilitated uptake and a lesser effect on prostate PC3 and colon Caco-2 cancer cells since the OATP1B1 mRNA and protein were only found in the normal liver and hepatocytes. The inhibition of cell growth was accompanied by distinct alterations in mitochondrial networks and dramatic changes in cellular morphology related to cofilin regulation and loss of p-caveolin. Both statins, hydrophilic pravastatin and hypdrophobic simvastatin caused redistribution of OATP1B1 and HMGCR to perinuclear sites. In conclusion, the specific chemical properties of different classes of statins dictate mechanistic properties which may be relevant when evaluating biological responses to statins.

The effect of demographic and clinical factors on the relationship between BMI and PSA levels

INTRODUCTION

Studies have reported lower prostate specific antigen (PSA) levels in men with a higher body mass index (BMI). Additional factors such as diabetes mellitus, benign prostatic hyperplasia (BPH) and certain medications may also affect PSA levels and confound the PSA-BMI association. In this study we evaluated the potential confounding effect of these factors on the obesity-PSA relationship and evaluated the association between these factors and PSA level.

METHODS

The study cohort consisted of 770 population-based controls without a history of prostate cancer (PCa) who participated in a prior PCa study. Demographic, anthropometric, and medical history data were obtained, and PSA level was determined from blood drawn at the time of interview. Linear regression was performed to evaluate the PSA-BMI relationship, adjusting for potential confounders. Finally, a forward stepwise algorithm was used to determine which factors were independently associated with PSA values.

RESULTS

With increase in BMI (<25, 25-29, ≥30), the geometric mean PSA level declined (1.18, 1.13, and 0.94, respectively); obese men had a 17% (95% CI 0.70-0.99) lower age-adjusted PSA level compared to normal weight men. However, this relationship was non-significant (P = 0.17) in the multivariate model. Independent predictors of PSA level included age (β = 1.03, 95% CI 1.02-1.04), history of BPH (β = 1.48, 95% CI 1.27-1.72), current statin (β = 0.85, 95% CI 0.74-0.98), and NSAID use (β = 0.84, 95% CI 0.72-0.98).

CONCLUSION

The relationship between obesity and PSA is confounded by a number of factors, which likely explain the observed inverse association previously reported. These results should help in interpreting PSA values in men screened for PCa.