A population-based study of daily nonsteroidal anti-inflammatory drug use and prostate cancer

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

Intake of Non-steroidal Anti-inflammatory Drugs and the Risk of Prostate Cancer: A Meta-Analysis

Background: Epidemiological evidences regarding the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer (PC) is still controversial. Therefore, we conducted a meta-analysis to explore the controversy that exists.

Methods: Electronic databases including Medline, EMBASE, Web of Science, Cochrane Library, BIOSIS, Scopus, CBM, CNKI, WANFANG, and CQVIP were used to search for and identify eligible studies published until December 31, 2017. Pooled effect estimates for the relative risk (RR) were computed through fixed-effects or random-effects models as appropriate. Publication bias was evaluated by Egger's and Begg's tests and potential sources of heterogeneity were investigated in subgroup analyses.

Results: A total of 43 observational studies were eligible for this meta-analysis. A protective effect was identified for the intake of any NSAIDs on the risk of PC (pooled RR = 0.89, 95% CI = 0.81–0.98). Moreover, the long-term intake of NSAIDs (≥5 years rather than ≥4 years) was associated with reduced PC incidence (pooled RR = 0.882, 95% CI = 0.785–0.991). Aspirin intake was also associated with a 7.0% risk reduction of PC (pooled RR = 0.93, 95% CI = 0.89–0.96). The inverse association became stronger for advanced PC and PC with a Gleason score ≥7 compared to the association with total PC. Interestingly, it was the daily dose (≥1 pill/day) rather than, long-term aspirin intake (≥4 or ≥5 years) that was associated with reduced PC incidence (pooled RR = 0.875, 95% CI = 0.792–0.967). The pooled effects for non-aspirin NSAIDs demonstrated no significantly adverse or beneficial effects on total PC, advanced PC, or PC with Gleason score ≥7, though all pooled RRs were >1.

Conclusions: Our findings suggested a protective effect of the intake of any NSAIDs on the risk of PC, especially in those who took the NSAIDs for a long period. Moreover, aspirin intake was also associated with a decreased risk of PC, and there was a dose related association between aspirin intake and the risk of PC, while no significant effects of long-term aspirin intake were found on the PC incidence.

Chemoprevention in Prostate Cancer: Current Perspective and Future Directions

Chemoprevention of prostate cancer aims to reduce the mortality as well as the public burden of overdetection, which increases anxiety, cost, and morbidity related to the disease. The role of 5-α-reductase inhibitors has been well investigated and shown to decrease the risk of prostate cancer. No current evidence exists to encourage the use of nutrients or vitamins as chemopreventive agents. The modulation of inflammation is one of the most promising targets for chemoprevention of prostate cancer.

Adding Celecoxib With or Without Zoledronic Acid for Hormone-Naïve Prostate Cancer: Long-Term Survival Results From an Adaptive, Multiarm, Multistage, Platform, Randomized Controlled Trial

Purpose Systemic Therapy for Advanced or Metastatic Prostate Cancer: Evaluation of Drug Efficacy is a randomized controlled trial using a multiarm, multistage, platform design. It recruits men with high-risk, locally advanced or metastatic prostate cancer who were initiating long-term hormone therapy. We report survival data for two celecoxib (Cel)-containing comparisons, which stopped accrual early at interim analysis on the basis of failure-free survival. Patients and Methods Standard of care (SOC) was hormone therapy continuously (metastatic) or for ≥ 2 years (nonmetastatic); prostate (± pelvic node) radiotherapy was encouraged for men without metastases. Cel 400 mg was administered twice a day for 1 year. Zoledronic acid (ZA) 4 mg was administered for six 3-weekly cycles, then 4-weekly for 2 years. Stratified random assignment allocated patients 2:1:1 to SOC (control), SOC + Cel, or SOC + ZA + Cel. The primary outcome measure was all-cause mortality. Results were analyzed with Cox proportional hazards and flexible parametric models adjusted for stratification factors. Results A total of 1,245 men were randomly assigned (Oct 2005 to April 2011). Groups were balanced: median age, 65 years; 61% metastatic, 14% N+/X M0, 25% N0M0; 94% newly diagnosed; median prostate-specific antigen, 66 ng/mL. Median follow-up was 69 months. Grade 3 to 5 adverse events were seen in 36% SOC-only, 33% SOC + Cel, and 32% SOC + ZA + Cel patients. There were 303 control arm deaths (83% prostate cancer), and median survival was 66 months. Compared with SOC, the adjusted hazard ratio was 0.98 (95% CI, 0.80 to 1.20; P = .847; median survival, 70 months) for SOC + Cel and 0.86 (95% CI, 0.70 to 1.05; P =.130; median survival, 76 months) for SOC + ZA + Cel. Preplanned subgroup analyses in men with metastatic disease showed a hazard ratio of 0.78 (95% CI, 0.62 to 0.98; P = .033) for SOC + ZA + Cel. Conclusion These data show no overall evidence of improved survival with Cel. Preplanned subgroup analyses provide hypotheses for future studies.

Inflammation in prostate cancer progression and therapeutic targeting

Chronic inflammation contributes to the onset and progression of human cancer, via modifications in the tumor microenvironment by remodeling the extracellular matrix (ECM) and initiating epithelial mesenchymal transition (EMT). At the biological level, chronically inflamed cells release cytokines that are functionally dictating a constitutively active stroma, promoting tumor growth and metastasis. In prostate cancer, inflammation correlates with increased development of “risk factor” lesions or proliferative inflammatory atrophy (PIA). Chronic inflammation in benign prostate biopsy specimens can be associated with high-grade prostate tumors in adjacent areas. In this article, we discuss the current understanding of the incidence of inflammation in prostate cancer progression and the significance of the process in therapeutic targeting of specific inflammatory signaling pathways and critical effectors during tumor progression. Further understanding of the process of chronic inflammation in prostate tumor progression to metastasis will enable development and optimization of novel therapeutic modalities for the treatment of high-risk patients with advanced disease.

Meta-analysis of nonsteroidal anti-inflammatory drug intake and prostate cancer risk

Background

Epidemiological studies of the association between nonsteroidal anti-inflammatory drug (NSAID) intake and the risk of prostate cancer still remain controversial. Therefore, we conducted a meta-analysis to evaluate the potential association between NSAID intake and prostate cancer risk.

Methods

Eligible studies were retrieved by both computerized searches and reviews of references. Subgroup analyses on country and design of study were also performed. Random or fixed-effect models were used to pool estimates of odds ratios (ORs) with 95% confidence intervals (CIs).

Results

We observed that the intake of aspirin was associated with a marginally decreased risk of prostate cancer (OR =0.95, 95% CI =0.93 to 0.98). A similar result was found between nonaspirin NSAIDs and prostate cancer risk (OR =0.94, 95% CI =0.90 to 0.98). However, a positive relation between all-NSAID intake and prostate cancer risk was observed (OR =1.18, 95% CI =1.15 to 1.22).

Conclusions

We observed a marginally inverse correlation between the intake of aspirin and prostate cancer risk. On the contrary, a positive relationship between all-NSAID intake and prostate cancer was detected. Further research needs to be conducted to better clarify potential biological mechanisms.

A tale of two trials: The impact of 5α-reductase inhibition on prostate cancer (Review)

The use of 5α-reductase inhibitors (5α-RIs) as prostate cancer chemoprevention agents is controversial. Two large randomized trials, the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) Trial, have both shown a decreased incidence of prostate cancer in patients administered with 5α-RIs. Both studies showed, however, an increased risk of higher-grade prostate cancer. Numerous studies have since analyzed the inherent biases in these landmark studies and have used mathematical modeling to estimate the true incidence of prostate cancer and the risk for high-grade prostate cancer in patients undergoing 5α-RI treatment. All primary publications associated with the PCPT and REDUCE studies were reviewed in detail. Pertinent references from the above publications were assessed and a literature search of all published articles associated with PCPT, REDUCE or 5α-RIs as chemopreventative agents through October 2013 was performed using Pubmed/Medline. PCPT and REDUCE both showed a significant decrease in the incidence of prostate cancer following the administration of 5α-reductase inhibitor, as compared with placebo, suggesting that 5α-RIs may be effective agents for prostate cancer chemoprevention. Inherent biases in the design of these two studies may have caused an artificial increase in the number of high-grade cancers reported. Mathematical models, that integrated data from these trials, revealed neither an increased nor decreased risk of high-grade disease when taking these biases into consideration. Moderately strong evidence exists that 5α-RIs may reduce the risk of prostate cancer. PCPT and REDUCE showed a decreased prevalence of prostate cancer in patients taking 5α-RIs. Urologists should have a working knowledge of these studies and discuss with patients the risks and benefits of 5α-RI treatment. Further studies to evaluate the cost-effectiveness of chemoprevention with 5α-RIs and appropriate patient selection are warranted.

Nonsteroidal anti-inflammatory drugs and prostatic diseases

Prostatic diseases are characterized by increased activity of cytokines, growth factors, and cyclooxygenases- (COX-) 1 and 2. Activation of COX-1 and COX-2 results in increased levels of prostaglandins and the induction of angiogenic, antiapoptotic and inflammatory processes. Inhibition of COX enzymes by members of the widely used nonsteroidal anti-inflammatory drug (NSAID) class of drugs decreases prostaglandin production, and exerts a variety of anti-inflammatory, antipyretic, and antinociceptive effects. While numerous in vitro, in vivo, and clinical studies have shown that NSAIDs inhibit the risk and progression of prostatic diseases, the relationship between NSAIDs and such diseases remains controversial. Here we review the literature in this area, critically analyzing the benefits and caveats associated with the use of NSAIDs in the treatment of prostatic diseases.

Effect of aspirin and other non-steroidal anti-inflammatory drugs on prostate cancer incidence and mortality: a systematic review and meta-analysis

BACKGROUND

It has been postulated that non-steroidal anti-inflammatory drugs (NSAIDs) use leads to decreased prostate cancer (PCa) risk. In recent years, NSAIDs' role in PCa development has been extensively studied; however, there is not yet a definitive answer. Moreover, the epidemiological results for NSAIDs' effect on PCa-specific mortality have been inconsistent. Therefore, we performed a meta-analysis to examine the controversy.

METHODS

We performed a literature database search and included all published studies conducted in the general population exposed to any NSAID, extracting an odds ratio (OR) or a hazard ratio (HR) with 95% confidence intervals (95% CIs) that compared the incidence of PCa or PCa-specific mortality with non-exposure. We derived a pooled OR or HR using random or fixed effects models, as appropriate. Subgroup analyses were also performed.

RESULTS

Thirty-nine studies (20 case-control and 19 cohort studies) were included in this analysis. Thirty-one studies were available concerning NSAID use and PCa incidence and eight studies on PCa-specific mortality. Compared to non-use, aspirin use was statistically significantly associated with PCa incidence risk, and the association was slightly stronger for advanced PCa than for total PCa (OR = 0.92, 95% CI = 0.87 to 0.97 for total PCa; OR = 0.81, 95% CI = 0.73 to 0.89 for advanced PCa). Aspirin use seems also to be associated with a modest reduction in PCa-specific mortality (HR = 0.86, 95% CI = 0.78 to 0.96 for total PCa; OR = 0.81, 95% CI = 0.71 to 0.92 for advanced PCa). Generally, the pooled effects for any NSAIDs, NA-NSAIDs and cyclooxygenase-2 inhibitors demonstrated no adverse or beneficial effects on PCa development or PCa-specific mortality, but the results were not consistent. The effect estimates did not vary markedly when stratified by study design and study quality but varied by geographic region. Furthermore, long-term aspirin use (≥ 4 years) was also significantly associated with reduced PCa incidence (OR = 0.88, 95% CI 0.79 to 0.99).

CONCLUSIONS

The present meta-analysis provides support for the hypothesis that aspirin use is inversely related to PCa incidence and PCa-specific mortality. The effect estimates, varying by geographic region, deserve further investigation.

Management of prostate cancer. Part 1: chemoprevention

Numerous agents have been investigated in prostate cancer prevention. Many manipulate sex steroid levels or function, some regulate response to oxidative stress and others affect tumor proliferation and/or apoptosis. Some are postulated to even affect downstream targets, such as cyclooxygenase-2, which has been shown to be elevated in prostate cancer by most investigators. The evidence for all these potential chemopreventive agents is critically reviewed. While the current information base is vast, level 1 evidence is lacking, and ongoing trials are not due to provide such evidence for many years to come. In addition, the current lack of ability to accurately differentiate clinically important prostate cancer from latent disease makes chemoprevention in this setting even more challenging. Currently, no reliable biomarkers that can act as surrogate endpoints for the development of clinically relevant prostate cancer exist, which makes performing large chemoprevention trials expensive. At present, there is little to suggest that the urologist or General Practitioner should be recommending any particular chemopreventive agent to either the general population or those deemed to be at higher risk of contracting prostate cancer.

Prostate cancer chemoprevention

Prostate cancer is a leading cause of morbidity and mortality in men and has significant treatment-associated complications. Prostate cancer chemoprevention has the potential to decrease the morbidity and mortality associated with this disease. Chemoprevention research to date has primarily focused on nutrients and 5 alpha-reductase inhibitors (5ARIs). A large randomized trial (SELECT) found no favorable effect of selenium or vitamin E on prostate cancer prevention. Two large randomized placebo controlled trials (the PCPT and REDUCE trials) have been published and have supported the role of 5ARIs in prostate cancer chemoprevention; however, these trials also have prompted concerns regarding the increase in high-grade disease seen with treatment and have not been approved by the US Food and Drug Administration (FDA) for chemoprevention. Conclusive evidence for the chemopreventive benefit of nutrients or vitamins is lacking, whereas the future role of 5ARIs remains to be clarified.

Nonsteroidal anti-inflammatory drugs and prostate cancer: a systematic review of the literature and meta-analysis

Prostate cancer is the most common visceral cancer in men. Many studies have shown that nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the risk of prostate cancer. We systematically searched all relevant databases (MEDLINE, EMBASE, The Cochrane Collaboration, CINAHL, Database of Abstracts of Review of Effects and ACP Journal Club) to March 2008. We also explored bibliographies of the articles, pertinent journals and conferences. We selected relevant articles according to predefined inclusion criteria by 2 independent reviewers. We used both fixed and random-effect models for meta-analysis. We performed subgroup and sensitivity analysis based on predefined variables. From 962 extracted articles, 20 met the inclusion criteria with a total of 25 768 participants. All the studies had an observational design. There was a statistically significant protective effect for NSAIDs on risk of prostate cancer (odds ratio [OR] 0.92, 95% confidence interval [CI] 0.86-0.97). Subgroup analysis did not show any effect of study design or quality score on the results. There was a small but statistically significant protective effect for acetylsalicylic acid (ASA) (OR 0.95, 95% CI 0.91-1.00). Exposure to non-ASA NSAIDs was associated with a slightly reduced likelihood of prostate cancer (OR 0.92, 95% CI 0.85-1.00). With the available data, we were not able to determine an optimum dosage for NSAIDs. We conclude that taking NSAIDs may reduce the risk of prostate cancer. Nevertheless, the effect is small.

Inhibition of COX-2 expression by topical diclofenac enhanced radiation sensitivity via enhancement of TRAIL in human prostate adenocarcinoma xenograft model

BACKGROUND

COX-2 inhibitors have an antitumor potential and have been verified by many researchers. Treatment of cancer cells with external stressors such as irradiation can stimulate the over-expression of COX-2 and possibly confer radiation resistance. In this study, we tested if topical diclofenac, which inhibits both COX-1 and COX-2, administration rendered prostate tumor cells sensitize to the effects of radiation.

METHODS

LNCaP-COX-2 and LNCaP-Neo cells were treated with 0 to 1000 μM diclofenac. Next, a clonogenic assay was performed in which cells were subjected to irradiation (0 to 4 Gy) with or without diclofenac. COX-2 expression and other relevant molecules were measured by real-time PCR and immunohistochemistry after irradiation and diclofenac treatment. In addition, we assessed the tumor volumes of xenograft LNCaP-COX-2 cells treated with topical diclofenac with or without radiation therapy (RT).

RESULTS

LNCaP-COX-2 and LNCaP-Neo cell lines experienced cytotoxic effects of diclofenac in a dose related manner. Clonogenic assays demonstrated that LNCaP-COX-2 cells were significantly more resistant to RT than LNCaP-Neo cells. Furthermore, the addition of diclofenac sensitized LNCaP-COX-2 not but LNCaP-Neo cells to the cytocidal effects of radiation. In LNCaP-COX-2 cells, diclofenac enhanced radiation-induced apoptosis compared with RT alone. This phenomenon might be attributed to enhancement of RT-induced TRAIL expression as demonstrated by real-time PCR analysis. Lastly, tumor volumes of LNCaP-COX-2 cells xenograft treated with diclofenac or RT alone was >4-fold higher than in mice treated with combined diclofenac and radiation (p<0.05).

CONCLUSIONS

These in vitro and in vivo findings suggest that conventional COX inhibitor, diclofenac enhances the effect of RT on prostate cancer cells that express COX-2. Thus, diclofenac may have potential as radiosensitizer for treatment of prostate cancer.

Inflammation and prostate carcinogenesis

Quite a few epidemiological studies including meta-analyses indicate that prostate inflammation is associated with increased risk of prostate cancer. The cause of inflammation in the prostate is speculated to be several microorganisms that cause prostatitis or sexually transmitted infections. Other specific microorganisms, such as xenotropic murine leukemia virus-related virus, are also reported to relate to the development of prostate cancer; however, the contribution of this microorganism to prostate cancer development needs to be carefully interpreted. Environmental factors, especially dietary factors, might also be associated with prostate cancer development. Among related dietary factors, charred meat carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine might be a link between environmental factors and inflammation, because 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine has the potential to accelerate prostate inflammation through its estrogenic effect. In light of these findings, preventing or reducing prostate inflammation might be one strategy for chemoprevention of prostate cancer.

Aspirin but not ibuprofen use is associated with reduced risk of prostate cancer: a PLCO study

BACKGROUND

Although most epidemiological studies suggest that non-steroidal anti-inflammatory drug use is inversely associated with prostate cancer risk, the magnitude and specificity of this association remain unclear.

METHODS

We examined self-reported aspirin and ibuprofen use in relation to prostate cancer risk among 29 450 men ages 55-74 who were initially screened for prostate cancer from 1993 to 2001 in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Men were followed from their first screening exam until 31 December 2009, during which 3575 cases of prostate cancer were identified.

RESULTS

After adjusting for potential confounders, the hazard ratios (HRs) of prostate cancer associated with <1 and ≥ 1 pill of aspirin daily were 0.98 (95% confidence interval (CI), 0.90-1.07) and 0.92 (95% CI: 0.85-0.99), respectively, compared with never use (P for trend 0.04). The effect of taking at least one aspirin daily was more pronounced when restricting the analyses to men older than age 65 or men who had a history of cardiovascular-related diseases or arthritis (HR (95% CI); 0.87 (0.78-0.97), 0.89 (0.80-0.99), and 0.88 (0.78-1.00), respectively). The data did not support an association between ibuprofen use and prostate cancer risk.

CONCLUSION

Daily aspirin use, but not ibuprofen use, was associated with lower risk of prostate cancer risk.

Celecoxib plus hormone therapy versus hormone therapy alone for hormone-sensitive prostate cancer: first results from the STAMPEDE multiarm, multistage, randomised controlled trial

Background

Long-term hormone therapy alone is standard care for metastatic or high-risk, non-metastatic prostate cancer. STAMPEDE—an international, open-label, randomised controlled trial—uses a novel multiarm, multistage design to assess whether the early additional use of one or two drugs (docetaxel, zoledronic acid, celecoxib, zoledronic acid and docetaxel, or zoledronic acid and celecoxib) improves survival in men starting first-line, long-term hormone therapy. Here, we report the preplanned, second intermediate analysis comparing hormone therapy plus celecoxib (arm D) with hormone therapy alone (control arm A).

Methods

Eligible patients were men with newly diagnosed or rapidly relapsing prostate cancer who were starting long-term hormone therapy for the first time. Hormone therapy was given as standard care in all trial arms, with local radiotherapy encouraged for newly diagnosed patients without distant metastasis. Randomisation was done using minimisation with a random element across seven stratification factors. Patients randomly allocated to arm D received celecoxib 400 mg twice daily, given orally, until 1 year or disease progression (including prostate-specific antigen [PSA] failure). The intermediate outcome was failure-free survival (FFS) in three activity stages; the primary outcome was overall survival in a subsequent efficacy stage. Research arms were compared pairwise against the control arm on an intention-to-treat basis. Accrual of further patients was discontinued in any research arm showing safety concerns or insufficient evidence of activity (lack of benefit) compared with the control arm. The minimum targeted activity at the second intermediate activity stage was a hazard ratio (HR) of 0·92. This trial is registered with ClinicalTrials.gov, number NCT00268476, and with Current Controlled Trials, number ISRCTN78818544.

Findings

2043 patients were enrolled in the trial from Oct 17, 2005, to Jan 31, 2011, of whom 584 were randomly allocated to receive hormone therapy alone (control group; arm A) and 291 to receive hormone therapy plus celecoxib (arm D). At the preplanned analysis of the second intermediate activity stage, with 305 FFS events (209 in arm A, 96 in arm D), there was no evidence of an advantage for hormone therapy plus celecoxib over hormone therapy alone: HR 0·98 (95% CI 0·90–1·06). 2-year FFS was 51% (95% CI 46–56) in arm A and 51% (95% CI 43–58) in arm D. There was no evidence of differences in the incidence of adverse events between groups (events of grade 3 or higher were noted at any time in 123 [23%, 95% CI 20–27] patients in arm A and 64 [25%, 19–30] in arm D). The most common grade 3–5 events adverse effects in both groups were endocrine disorders (55 [11%] of patients in arm A vs 19 [7%] in arm D) and musculoskeletal disorders (30 [6%] of patients in arm A vs 15 [6%] in arm D). The independent data monitoring committee recommended stopping accrual to both celecoxib-containing arms on grounds of lack of benefit and discontinuing celecoxib for patients currently on treatment, which was endorsed by the trial steering committee.

Interpretation

Celecoxib 400 mg twice daily for up to 1 year is insufficiently active in patients starting hormone therapy for high-risk prostate cancer, and we do not recommend its use in this setting. Accrual continues seamlessly to the other research arms and follow-up of all arms will continue to assess effects on overall survival.

Funding

Cancer Research UK, Pfizer, Novartis, Sanofi-Aventis, Medical Research Council (London, UK).

Risk of Prostate Cancer after Trans Urethral Resection of BPH: A Cohort and Nested Case-Control Study

Epidemiological and experimental evidence suggests that inflammation plays a role in both prostate cancer (PCa) and benign prostate hyperplasia (BPH). This study evaluates the risk of PC after transurethral resection (TURP) for BPH and estimates the PCa risk related to presence of inflammation in the resected material. The Pathology Department at the University Hospital of Umeå (Umeå, Sweden) identified BPH cases (n = 7,901) that underwent TURP between 1982 and 1997. Using these pathological specimens, we compared the incidence of PCa in the cohort to the population and calculated the standardized incidence and mortality ratios (SIR and SMR). Inflammation, the androgen receptor (AR), and p53 were evaluated in a nested case-control study of 201 cases and controls. Inflammation was graded severe or mild-moderate. In the follow-up period after TURP, cases developed prostate cancer and the controls did not. After TURP, SIR for prostate cancer increased [1.26, CI 95% (1.17–1.35) ], whereas SMR decreased [0.59, CI 95% (0.47–0.73) ]. Presence of inflammation at the time of TURP did not differ between cases and controls nor were there differences in p53 or AR staining. The data suggest a small increased risk of PCa after TURP and decreased PCa mortality. Inflammation at the time of TURP is not associated with PCa risk in this material. The increased PCa risk may be attributed to increased surveillance and PSA screening.

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.

Associations of aspirin, nonsteroidal anti-inflammatory drug and paracetamol use with PSA-detected prostate cancer: findings from a large, population-based, case-control study (the ProtecT study)

Evidence from laboratory studies suggests that chronic inflammation plays an important role in prostate cancer aetiology. This has resulted in speculation that nonsteroidal anti-inflammatory drugs may protect against prostate cancer development. We analysed data from a cross-sectional case-control study (n(cases) = 1,016; n(controls) = 5,043), nested within a UK-wide population-based study that used prostate specific antigen (PSA) testing for identification of asymptomatic prostate cancers, to investigate the relationship of aspirin, nonsteroidal anti-inflammatory drug (NSAID) and paracetamol use with prostate cancer. In conditional logistic regression models accounting for stratum matching on age (5-year age bands) and recruitment centre, use of non-aspirin NSAIDs [odds ratio (OR) = 1.32; 95% confidence interval (CI): 1.04-1.67] or all NSAIDs (OR = 1.25; 95% CI = 1.07-1.47) were positively associated with prostate cancer. There were weaker, not conventionally statistically significant, positive associations of aspirin (OR = 1.13; 95% CI = 0.94-1.36) and paracetamol (OR = 1.20; 95% CI = 0.90-1.60) with prostate cancer. Mutual adjustment for aspirin, non-aspirin NSAIDs or paracetamol made little difference to these results. There was no evidence of confounding by age, family history of prostate cancer, body mass index or self-reported diabetes. Aspirin, NSAID and paracetamol use were associated with reduced serum PSA concentrations amongst controls. Our findings do not support the hypothesis that NSAIDs reduce the risk of PSA-detected prostate cancer. Our conclusions are unlikely to be influenced by PSA detection bias because the inverse associations of aspirin, NSAID and paracetamol use with serum PSA would have attenuated (not generated) the observed positive associations.

Long-term aspirin use and the risk of total, high-grade, regionally advanced and lethal prostate cancer in a prospective cohort of health professionals, 1988-2006

Experimental studies suggest a role for aspirin in the chemoprevention of prostate cancer and epidemiological evidence supports a modest inverse association between regular aspirin use and prostate cancer risk, especially for advanced disease. In a prospective cohort study of 51,529 health professionals aged 40-75 years at baseline, we evaluated long-term aspirin use and the incidence of total, high-grade (Gleason 8-10, n = 488), regionally advanced (T3b-T4 or N1, n = 228) and lethal prostate cancer (M1, bony metastases or prostate cancer death, n = 580) from 1988-2006. We used Cox proportional hazards regression to evaluate risk associated with frequency (days/week), quantity (tablets/week), recency and duration of aspirin use after multivariable adjustment for confounders and other predictors of prostate cancer risk. A total of 4,858 men were diagnosed with prostate cancer during the 18-year study period. Men taking ≥ 2 adult-strength aspirin tablets a week had a 10% lower risk of prostate cancer (p-for-trend = 0.02). For regionally advanced cancer, we observed no significant associations with aspirin use. For high-grade and lethal disease, men taking ≥ 6 adult-strength tablets/week experienced similar reductions in risk hazard ratio [HR = 0.72 (95% confidence intervals [CI]: 0.54, 0.96) and HR = 0.71 (95% CI: 0.50, 1.00)]. Analytical approaches to address bias from more frequent prostate-specific antigen screening among aspirin users did not yield different conclusions. We observed reductions in the risk of high-grade and lethal prostate cancer associated with higher doses of aspirin, but not with greater frequency or duration, in a large, prospective cohort of health professionals. Our data support earlier observations of modest inverse associations with advanced prostate cancer.

Non-Steroidal Anti-Inflammatory Drugs, Variation in Inflammatory Genes, and Aggressive Prostate Cancer

Increasing evidence suggests that prostatic inflammation plays a key role in the development of prostate cancer. It remains controversial whether non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of prostate cancer. Here, we investigate how a previously reported inverse association between NSAID use and the risk of aggressive prostate cancer is modulated by variants in several inflammatory genes. We found that NSAIDs may have differential effects on prostate cancer development, depending on one’s genetic makeup. Further study of these inflammatory pathways may clarify the mechanisms through which NSAIDs impact prostate cancer risk.

Use of nonsteroidal anti-inflammatory drugs and prostate cancer risk: a meta-analysis

The association between use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer remains controversial despite many observational epidemiological studies. We conducted a systematic meta-analysis of these studies to examine both the strength and the consistency of the association, and to explore sources of variability between studies. We searched 12 computerized literature databases for reports published before June 2008 and included any epidemiologic studies where the outcome was prostate cancer incidence or mortality, and the exposure was use of NSAIDs. Studies that met the inclusion criteria comprised 10 case-control and 14 cohort studies with a total of 24,230 prostate cancer cases. Studies that assessed the effect of aspirin use on total prostate cancer had a pooled odds ratio (POR) of 0.83 (95%CI: 0.77-0.89), whereas those that assessed the effect of aspirin on advanced prostate cancer had a POR of 0.81 (0.72-0.92). Studies that examined the effects of non-aspirin NSAIDs or all NSAIDs were less consistent but still suggestive of reduced risks. However, most reviewed studies were limited by exposure and disease misclassification, by inadequate information on dose and duration of use and by the possibility of screening and other biases. In conclusion, the epidemiologic evidence for a protective effect of aspirin and other NSAID use against prostate cancer is suggestive but not conclusive. There is a need for well-designed observational studies with adequate exposure measurements, accurate case definition, attention to latency effects, and careful adjustment for screening and other biases.

Use of aspirin and other nonsteroidal antiinflammatory medications in relation to prostate cancer risk

Recent interest has focused on the role that inflammation may play in the development of prostate cancer and whether use of aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) affects risk. In a population-based case-control study designed to investigate the relation between these medications and prostate cancer risk, detailed exposure data were analyzed from 1,001 cases diagnosed with prostate cancer between January 1, 2002, and December 31, 2005, and 942 age-matched controls from King County, Washington. A significant 21% reduction in the risk of prostate cancer was observed among current users of aspirin compared with nonusers (95% confidence interval (CI): 0.65, 0.96). Long-term use of aspirin (>5 years: odds ratio = 0.76, 95% CI: 0.61, 0.96) and daily use of low-dose aspirin (odds ratio = 0.71, 95% CI: 0.56, 0.90) were also associated with decreased risk. There was no evidence that the association with aspirin use varied by disease aggressiveness, but there was effect modification (P(interaction) = 0.02) with a genetic variant in prostaglandin-endoperoxide synthase 2 (PTGS2) (rs12042763). Prostate cancer risk was not related to use of either nonaspirin NSAIDs or acetaminophen. These results contribute further evidence that aspirin may have chemopreventive activity against prostate cancer and highlight the need for additional research.

Impact of common medications on serum total prostate-specific antigen levels: analysis of the National Health and Nutrition Examination Survey

PURPOSE

Previous studies suggest that some common medications alter prostate-specific antigen (PSA) levels. It remains unclear whether these reported medication effects are due to clinicodemographic factors or concurrent use of other medications. We investigated the impact of individual and combinations of common medications on PSA in a large cross-sectional study of the United States population.

PATIENTS AND METHODS

The study included men > or = 40 years old without prostate cancer from the 2003 to 2004 and 2005 to 2006 cycles of the National Health and Nutrition Examination Survey (NHANES). Men with recent prostate manipulation, prostatitis, and those on hormone therapy were excluded. Weighted multivariate linear regression was performed on log-transformed total PSA to determine the effect of the 10 most commonly prescribed medication classes, adjusting for potential confounders including demographics, clinical characteristics, physical examination, laboratory studies, and duration of medication use.

RESULTS

In total, 1,864 men met inclusion criteria. Nonsteroidal anti-inflammatory drug (NSAID; P = .03), statin (P = .01), and thiazide diuretic (P = .025) intake was inversely related to PSA levels. Five years of NSAID, statin, and thiazide diuretic use was associated with PSA levels lower by 6%, 13%, and 26%, respectively. The combination of statins and thiazide diuretics showed the greatest reduction in PSA levels: 36% after 5 years. Concurrent calcium channel blocker use minimizes or negates the inverse relationship of statin use and PSA level.

CONCLUSION

We found that men using NSAIDs, statins, and thiazide diuretics have reduced PSA levels by clinically relevant amounts. The impact of regularly consuming these common medications on prostate cancer screening is unknown.

Synthesis and antitumor properties of selenocoxib-1 against rat prostate adenocarcinoma cells

Hormone refractory prostate cancer poses a huge problem and standard of care chemotherapy has not been very successful. We used a novel strategy to combine properties of 2 well-studied class of compounds (selenium and COX-2 inhibitor) and examined the resulting effectiveness against prostate cancer. Bearing in mind that sulfonamide moiety and pyrazole ring is important for the proapoptotic activity of Celecoxib, we synthesized a selenium derivative, Selenocoxib-1, by modifying Celecoxib at position 3 of the pyrazole ring. The PAIII cells derived from a metastatic prostate tumor that arose spontaneously in a Lobund-Wistar (LW) rat were used to examine the efficacy of Selenocoxib-1 in vitro. In addition, human metastatic prostate cancer cells, PC-3M, were tested for antitumor effect of Selenocoxib-1 in vitro. The IC(50) in PAIII and PC-3M cells for Selenocoxib-1 was about 5 microM, while for Celecoxib it was more than 20 microM. Selenocoxib-1 induced apoptosis in a dose-dependent manner in the PAIII cells. COX-2 expression in PAIII cells was downregulated by Celecoxib and Selenocoxib-1 at 20 and 5 microM, respectively; the COX-2 activity was, however, not affected by Selenocoxib-1. Following treatment with Selenocoxib-1, PAIII cells resulted in dose-dependent decrease in HIF-1alpha, p-AKT and Bcl-2 levels. A reduction in weights was observed in subcutaneous tumors produced by PAIII cells pretreated with Selenocoxib-1 as compared to Celecoxib in LW rats. Further, following 1 week Selenocoxib-1 treatment of PAIII tumors resulted in significant reduction of tumor weights. This study demonstrates that Selenocoxib-1 is more effective against prostate cancer than Celecoxib.

Characterization of scavengers of gamma-ketoaldehydes that do not inhibit prostaglandin biosynthesis

Expression of cyclooxygenase-2 (COX-2) is associated with the development of many pathologic conditions. The product of COX-2, prostaglandin H(2) (PGH(2)), can spontaneously rearrange to form reactive gamma-ketoaldehydes called levuglandins (LGs). This gamma-ketoaldehyde structure confers a high degree of reactivity on the LGs, which rapidly form covalent adducts with primary amines of protein residues. Formation of LG adducts of proteins has been demonstrated in pathologic conditions (e.g., increased levels in the hippocampus in Alzheimer's disease) and during physiologic function (platelet activation). On the basis of knowledge that lipid modification of proteins is known to cause their translocation and to alter their function, we hypothesize that modification of proteins by LG could have functional consequences. Testing this hypothesis requires an experimental approach that discriminates between the effects of protein modification by LG and the effects of cyclooxygenase-derived prostanoids acting through their G-protein coupled receptors. To achieve this goal, we have synthesized and evaluated a series of scavengers that react with LG with a potency more than 2 orders of magnitude greater than that with the epsilon-amine of lysine. A subset of these scavengers are shown to block the formation of LG adducts of proteins in cells without inhibiting the catalytic activity of the cyclooxygenases. Ten of these selective scavengers did not produce cytotoxicity. These results demonstrate that small molecules can scavenge LGs in cells without interfering with the formation of prostaglandins. They also provide a working hypothesis for the development of pharmacologic agents that could be used in experimental animals in vivo to assess the pathophysiological contribution of levuglandins in diseases associated with cyclooxygenase up-regulation.

Omega-3 fatty acids, genetic variants in COX-2 and prostate cancer

Dietary intake of fish and omega-3 polyunsaturated fatty acids (omega-3 PUFAs) may decrease the risk of prostate cancer development and progression to advanced stage disease. This could reflect the anti-inflammatory effects of PUFAs, possibly through mediation of cyclooxygenase (COX), a key enzyme in fatty acid metabolism and inflammation. Despite promising experimental evidence, epidemiological studies have reported somewhat conflicting results regarding the effects of fish/PUFAs on prostate cancer development and progression. The literature suggests that fish, and particularly long-chain omega-3 PUFAs, may have a more pronounced protective effect on biologically aggressive tumors or on their progression, and less on early steps of carcinogenesis. Moreover, the impact of LC omega-3 PUFAs may be modified by variation of the COX-2 gene. Overall, results to date support the hypothesis that long-chain omega-3 PUFAs may impact prostate inflammation and carcinogenesis via the COX-2 enzymatic pathway.

More Than Structural Cells, Fibroblasts Create and Orchestrate the Tumor Microenvironment

The tumor microenvironment comprises many cell types including infiltrating immune cells such as lymphocytes, endothelial cells and a complex stroma consisting mainly of fibroblasts. Fibroblasts are heterogeneous and consist of Thy-1+ and Thy-1- subsets that define different biosynthetic and differentiation potential. They produce mediators linked to carcinogenesis and metastasis, including Cox-2 and PGE2, both of which are also increased in most cancers. This review will highlight the emerging role of the complex fibroblastic stroma in establishing a microenvironment supporting malignant transformation, tumor growth and attenuation of host anti-tumor immune responses.

Antibiotic and anti-inflammatory use and the risk of prostate cancer

Background

Prostate inflammation or infection may increase the risk of prostate cancer. Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) are used to treat prostatitis and urinary tract infections (UTIs). The objective of our study was to assess whether their use decreases the risk of prostate cancer.

Methods

We conducted a case-control study among men with incident prostate cancer (N = 65 cases) and without prostate cancer (N = 195 controls) at the San Francisco Veteran Affairs medical center (VAMC) between June 1996 and June 2006. Cases were all patients who had prostate biopsies positive for cancer. We matched controls to cases on age group and race at a 3:1 ratio, and each matched pair was given an identical index date. Total antibiotic, aspirin, and NSAID use (number of prescriptions) was computed for each participant by drug type and was restricted to a fill date at least 1 year before the index date. Logistic regression was used for analysis. We adjusted for the matching variables (age group and race) and potential confounders (years of VAMC enrollment and number of clinic visits).

Results

Neither total antibiotic use nor total anti-inflammatory use reduces the risk of prostate cancer (P > 0.05).

Conclusion

Our analysis did not reveal a relation between use of antibiotics, aspirin, or NSAIDs and the risk of prostate cancer.

Carprofen induction of p75NTR-dependent apoptosis via the p38 mitogen-activated protein kinase pathway in prostate cancer cells

The p75 neurotrophin receptor (p75(NTR)) functions as a tumor suppressor in prostate epithelial cells, where its expression declines with progression to malignant cancer. Previously, we showed that treatment with R-flurbiprofen or ibuprofen induced p75(NTR) expression in several prostate cancer cell lines leading to p75(NTR)-mediated decreased survival. Using the 2-phenyl propionic acid moiety of these profens as a pharmacophore, we screened an in silico database of 30 million compounds and identified carprofen as having an order of magnitude greater activity for induction of p75(NTR) levels and inhibition of cell survival. Prostate (PC-3 and DU-145) and bladder (T24) cancer cells were more sensitive to carprofen induction of p75(NTR)-associated loss of survival than breast (MCF-7) and fibroblast (3T3) cells. Transfection of prostate cell lines with a dominant-negative form of p75(NTR) before carprofen treatment partially rescued cell survival, showing a cause-and-effect relationship between carprofen induction of p75(NTR) levels and inhibition of survival. Carprofen induced apoptotic nuclear fragmentation in prostate but not in MCF-7 and 3T3 cells. Furthermore, small interfering RNA knockdown of the p38 mitogen-activated protein kinase (MAPK) protein prevented induction of p75(NTR) by carprofen in both prostate cell lines. Carprofen treatment induced phosphorylation of p38 MAPK as early as within 1 min. Expression of a dominant-negative form of MK2, the kinase downstream of p38 MAPK frequently associated with signaling cascades leading to apoptosis, prevented carprofen induction of the p75(NTR) protein. Collectively, we identify carprofen as a highly potent profen capable of inducing p75(NTR)-dependent apoptosis via the p38 MAPK pathway in prostate cancer cells.

Systemic therapy for advancing or metastatic prostate cancer (STAMPEDE): a multi-arm, multistage randomized controlled trial

There is a need to improve the outcomes for men with high-risk localised, nodal or metastatic prostate cancer, or with aggressively relapsing disease after initial therapy for local disease. This group of men is currently managed with long-term hormone therapy. Thus we aim to evaluate the toxicity and efficacy of three different systemic therapies (docetaxel, zoledronic acid and celecoxib) used alone or combined at the initiation of hormone manipulation for high-risk prostate cancer. A novel statistical design (multi-arm, multistage method) simultaneously tests multiple distinct strategies in parallel against a single control arm. The trial has several 'stages', from initial confirmation of safety to a phase III assessment of survival, with a series of intervening activity stages. This method provides a means of assessing several agents more quickly and efficiently, and allows inactive treatments to be dropped from further study at an early stage. STAMPEDE has been designed to address in parallel the activity and efficacy of these agents for this patient group. It is a flagship randomized clinical trial for academic research into prostate cancer in the UK. More than 500 patients have been recruited on schedule, confirming the acceptability of this complex trial design to patients and clinicians. The trial targets a population of approximately 3000 patients. STAMPEDE is a major new trial with a novel design applicable to the synchronous testing of several agents. It is hoped that the results will improve outcomes for patients with high-risk prostate cancer. The design could be applicable to the study of new therapies in other cancer types. Continued efforts are required by the urological cancer community to maintain the excellent recruitment shown to date.

The arachidonic acid pathway and its role in prostate cancer development and progression

PURPOSE

The arachidonic acid pathway incorporates phospholipase, cyclooxygenase, lipoxygenase and epoxygenase enzymes. This pathway has been shown to have a major role in the development and progression of a number of cancers, including prostate cancer. We discuss the current status of research of this pathway in the area of prostate cancer, ranging from preclinical in vitro studies to human clinical trials.

MATERIALS AND METHODS

We performed an online search of the current and past peer reviewed literature on prostate cancer and arachidonic acid, phospholipase, cyclooxygenase, lipoxygenase, epoxygenase, platelet activating factor, prostaglandin and eicosanoid. We retrieved and evaluated all full-length articles published in English from the 1980s to January 2007.

RESULTS

Epidemiological evidence suggested that nonsteroidal anti-inflammatory drugs may decrease the risk of prostate cancer. This effect, presumably through the inhibition of cyclooxygenase-2, has been validated in preclinical studies. Cyclooxygenase-2 inhibition has also decreased the rate of prostate specific antigen increase in men with biochemical recurrence after treatment for prostate cancer. Although lipoxygenase and secretory phospholipase A2 inhibition was also effective for decreasing prostate cancer growth in preclinical studies, to our knowledge these strategies have not yet been used in clinical trials. Cytosolic phospholipase A2, platelet activating factor and epoxygenase need further investigation to determine a role in prostate cancer.

CONCLUSIONS

Evolving data suggest a significant role for some areas of the arachidonic acid pathway in prostate cancer. Inhibiting 1 or a number of these enzymes in combination may hold promise for future prostate cancer treatment.

Inflammation and prostate cancer: a future target for prevention and therapy?

Given its long natural history, prostate cancer has become an ideal model for the clinical and basic science study of neoplastic disease in distinct pathologic phases: tumor initiation, progression, invasion, and metastasis. Chronic or recurrent acute inflammation, a product of infectious agents or other sources, has potential promotional roles in each of these phases. Nonsteroidal anti-inflammatory drugs (NSAIDs), because of their ability to attenuate inflammation, as well as possibly direct anti-cancer properties associated with the inhibition of stromal cyclooxygenase-2, are potential candidates for clinical use in prostate cancer. Though epidemiologic evidence indicating a reduced risk of prostate cancer for NSAID users supports a chemoprotective benefit, observational assessment and clinical trials of these agents among large cohorts of prostate cancer patients are needed to determine their value in prostate cancer management.

Prostaglandin E2 induces vascular endothelial growth factor secretion in prostate cancer cells through EP2 receptor-mediated cAMP pathway

Prostaglandin E2 (PGE2) has been shown to induce expression of vascular endothelial growth factor (VEGF) and other signaling molecules in several cancers. PGE2 elicits its functions though four G-protein coupled membrane receptors (EP1-4). In this study, we investigated the role of EP receptors in PGE2-induced molecular events in prostate cancer cells. qRT-PCR analysis revealed that PC-3 cells express a substantially higher level of EP2 and moderately higher EP4 than DU145 and LNCaP cells. LNCaP cells had virtually no detectable EP2 mRNA. EP1 and EP3 mRNAs were not detected in these cells. Treatment of prostate cancer cells with PGE2 (1 nM-10 microM) increased both VEGF secretion and cyclic adenosine monophosphate (cAMP) production. Levels of induction in PC-3 cells were greater than in DU145 and LNCaP cells. The selective EP2 agonist CAY10399 also significantly increased VEGF secretion and cAMP production in PC-3 cells, but not in DU145 and LNCaP cells. Moreover, PGE2 and CAY10399 increased mitogen activated protein kinase/extracellular signal regulated kinase (MAPK/Erk) and Akt phosphorylation in PC-3 and DU145 cells, but not in LNCaP cells. However, neither the MAPK/Erk inhibitor U0126 nor the PI3K/Akt inhibitor LY294002 abolished PGE2-induced VEGF secretion in PC-3 cells. We further demonstrated that the adenylate cyclase activator forskolin and the cAMP anologue 8-bromo-cAMP mimicked the effects of PGE2 on VEGF secretion in PC-3 cells. Meanwhile, the adenylate cyclase inhibitor 2'5'-dideoxyadenosine, at concentrations that inhibited PGE2-induced cAMP, significantly blocked PGE2-induced VEGF secretion in PC-3 cells. We conclude that PGE2-induced VEGF secretion in prostate cancer cells is mediated through EP2-, and possibly EP4-, dependent cAMP signaling pathways.

Statin use and risk of prostate cancer in the California Men's Health Study cohort

Statins have known anticarcinogenic effects, however, evidence for long-term statin use as effective chemoprevention for prostate cancer is inconsistent. We examined the association between statin use and risk of prostate cancer among 69,047 eligible participants in the California Men's Health Study, a prospective cohort of Northern and Southern California Kaiser Permanente (KP) members, ages 45 to 69 years, initiated in 2002. Prostate cancer cases were identified by linkage to the KP California Cancer Registries. Statin exposure, estimated from automated KP outpatient pharmacy records (available since 1991 in Southern California and since 1994 in Northern California), was treated as time-varying and defined as the cumulative days dispensed of any statin from the first dispensing until a prostate cancer diagnosis, radical prostatectomy, termination of membership, or end of study (December 31, 2004). Cox proportional hazards models with age as the time scale were used to estimate rate ratios, while controlling for confounding variables. During follow-up, 888 prostate cancer cases, including 131 advanced cases, were identified. There was no association between ever statin use or <5 years use and prostate cancer. Conversely, >or=5 years use was associated with a 28% lower risk for prostate cancer compared with nonuse (adjusted rate ratio, 0.72; 95% confidence interval, 0.53-0.99). This association did not differ markedly for advanced disease. However, the association did seem to be restricted to those who regularly take nonsteroidal anti-inflammatory drugs. Our findings suggest that long-term statin use might be associated with a reduced risk of prostate cancer but perhaps only among regular nonsteroidal anti-inflammatory drug users.

Polymorphic variants in alpha-methylacyl-CoA racemase and prostate cancer

BACKGROUND

Alpha-methylacyl-CoA racemase (AMACR), which prepares branched chain fatty acids to be metabolized for energy and is implicated in the activation of the COX-inhibiting form of ibuprofen, is overexpressed in prostate cancer and its precursor lesions. Significant differences in AMACR allele frequencies have been reported for hereditary prostate cancer (HPC), but the relevance of AMACR in the context of its substrates have not been studied.

METHODS

We conducted a nested case-control study of 1,318 prostate cancer cases and 1,842 controls from the screening arm of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Five non-synonymous (nsSNP) and two intronic AMACR polymorphisms were genotyped. Conditional logistic regression models were used to evaluate the associations between the genetic variants and prostate cancer.

RESULTS

Overall, prostate cancer was not related to AMACR gene variants; however, risks for prostate cancer were significantly reduced among regular ibuprofen users who carried allele variants at four nsSNP loci (M9V, D175G, S201L, and K277E; all P(trend) < 0.05) or carried the TGTGCG haplotype (OR = 0.65; 95% CI 0.44-0.97). No AMACR-related associations were noted among nonregular ibuprofen users (all P(interaction) > 0.33).

CONCLUSION

AMACR gene variants were unrelated to prostate cancer overall in this study. The protective associations observed among ibuprofen users suggest that AMACR gene variants may enhance the chemopreventive effects of ibuprofen on prostate cancer risk.

The VIOXX in Prostate Cancer Prevention study: cardiovascular events observed in the rofecoxib 25 mg and placebo treatment groups

BACKGROUND

A double-blind, randomized, placebo-controlled study was designed to determine the cumulative incidence of developing prostate cancer over 6 years of treatment with rofecoxib 25 mg/day versus placebo. Before completion, this trial was terminated following the voluntary withdrawal of rofecoxib. (On September 30, 2004, Merck & Co., Inc. announced the voluntary worldwide withdrawal of rofecoxib from the market.) Here we report the cardiovascular (CV) safety data collected from this study.

METHODS

A total of 4741 men (44-81 years old) exhibiting prostate-specific antigen levels (PSA) between 2.5 and 10 ng/mL were enrolled. Patients were stratified by PSA level and use of low-dose aspirin (LDA), then randomized to rofecoxib 25 mg (n = 2369) or placebo (n = 2372). Safety data were analyzed in all patients receiving > or = 1 dose of study medication. All reported thrombotic CV events occurring on-treatment or within 14 days after study drug discontinuation were adjudicated by an independent panel of clinical experts blinded to treatment assignment. Rates per 100 patient-years and relative risk (RR) of thrombotic CV events, rofecoxib vs. placebo, were determined.

RESULTS

Approximately 36% of patients had > or = 2 CV risk factors or LDA indicated. Median treatment duration was 4.14 (range: 0.03-15.90) months. Twenty-nine patients (14 rofecoxib, rate 1.27; 15 placebo, rate 1.36) experienced confirmed thrombotic CV events; RR 0.94 (95% CI: 0.45, 1.94) vs. placebo. Four patients (one rofecoxib; three placebo) died due to a confirmed thrombotic event. Significantly (p = 0.002) more patients receiving rofecoxib (n = 20; 0.8%) experienced hypertension-related adverse events versus placebo (n = 2; 0.1%). There were no cases of congestive heart failure.

CONCLUSIONS

Rofecoxib 25 mg and placebo demonstrated similar risk of thrombotic CV events in this limited dataset.

Cyclooxygenase-2 (cox-2) and the inflammogenesis of cancer

Cohesive scientific evidence from molecular, animal, and human investigations supports the hypothesis that aberrant induction of COX-2 and up-regulation of the prostaglandin cascade play a significant role in carcinogenesis, and reciprocally, blockade of the process has strong potential for cancer prevention and therapy. Supporting evidence includes the following: [1] expression of constitutive COX-2-catalyzed prostaglandin biosynthesis is induced by most cancer-causing agents including tobacco smoke and its components (polycylic aromatic amines, heterocyclic amines, nitrosamines), essential polyunsaturated fatty acids (unconjugated linoleic acid), mitogens, growth factors, proinflammatory cytokines, microbial agents, tumor promoters, and other epigenetic factors, [2] COX-2 expression is a characteristic feature of all premalignant neoplasms, [3] COX-2 expression is a characteristic feature of all malignant neoplasms, and expression intensifies with stage at detection and cancer progression and metastasis, [4] all essential features of carcinogenesis (mutagenesis, mitogenesis, angiogenesis, reduced apoptosis, metastasis, and immunosuppression) are linked to COX-2-driven prostaglandin (PGE-2) biosynthesis, [5] animal studies show that COX-2 up-regulation (in the absence of genetic mutations) is sufficient to stimulate the transformation of normal cells to invasive cancer and metastatic disease, [6] non-selective COX-2 inhibitors, such as aspirin and ibuprofen, reduce the risk of human cancer and precancerous lesions, and [7] selective COX-2 inhibitors, such as celecoxib, reduce the risk of human cancer and precancerous lesions at all anatomic sites thus far investigated. Results confirming that COX-2 blockade is effective for both cancer prevention and therapy have been tempered by observations that some COX2 inhibitors pose a risk to the cardiovascular system, and more studies are needed in order to determine if certain of these drugs can be taken at dosages that prevent cancer without increasing cardiovascular risk. It is emphasized that the "inflammogenesis model of cancer" is not mutually exclusive and may in fact be synergistic with the accumulation of somatic mutations in tumor suppressor genes and oncogenes or epigenetic factors in the development of cancer.