Lifestyle and dietary factors in the prevention of lethal prostate cancer

Midlife metabolic factors and prostate cancer risk in later life

Metabolic syndrome is associated with several cancers, but evidence for aggressive prostate cancer is sparse. We prospectively investigated the influence of metabolic syndrome and its components on risk of total prostate cancer and measures of aggressive disease in a cohort of Icelandic men. Men in the Reykjavik Study (n = 9,097, enrolled 1967-1987) were followed for incident (n = 1,084 total; n = 378 advanced; n = 148 high-grade) and fatal (n = 340) prostate cancer until 2014. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for (1) measured metabolic factors at cohort entry (body mass index (BMI), blood pressure, triglycerides, fasting blood glucose) and (2) a metabolic syndrome score (range 0-4) combining the risk factors: BMI ≥30 kg/m² ; systolic blood pressure (SBP) ≥130 or diastolic blood pressure (DBP) ≥85 mm Hg or taking antihypertensives; triglycerides ≥150 mg/dl; fasting blood glucose ≥100 mg/dl or self-reported type 2 diabetes. Hypertension and type 2 diabetes were associated with a higher risk of total, advanced, high-grade, and fatal prostate cancer, independent of BMI. Neither BMI nor triglycerides were associated with prostate cancer risk. Higher metabolic syndrome score (3-4 vs 0) was associated with a higher risk of fatal prostate cancer (HR 1.55; 95% CI: 0.89, 2.69; p trend = 0.08), although this finding was not statistically significant. Our findings suggest a positive association between midlife hypertension and diabetes and risk of total and aggressive prostate cancer. Further, metabolic syndrome as a combination of factors was associated with an increased risk of fatal prostate cancer.

Diet, Physical Activity, and Body Weight in Cancer Survivorship

Diet, physical activity, and body weight have been shown to play an important role in cancer survivorship. The impact of each of these lifestyle factors differs slightly among cancer types, and adherence to recommended diet and physical activity guidelines has been associated with positive outcomes, including decrease in the risk of cancer recurrence and improvement of quality of life. Although there are compelling data that appropriate diet, physical activity, and body weight have beneficial effects in cancer survivorship, additional trials are needed to understand the relationship.

Risk Model for Prostate Cancer Using Environmental and Genetic Factors in the Spanish Multi-Case-Control (MCC) Study

Prostate cancer (PCa) is the second most common cancer among men worldwide. Its etiology remains largely unknown compared to other common cancers. We have developed a risk stratification model combining environmental factors with family history and genetic susceptibility. 818 PCa cases and 1,006 healthy controls were compared. Subjects were interviewed on major lifestyle factors and family history. Fifty-six PCa susceptibility SNPs were genotyped. Risk models based on logistic regression were developed to combine environmental factors, family history and a genetic risk score. In the whole model, compared with subjects with low risk (reference category, decile 1), those carrying an intermediate risk (decile 5) had a 265% increase in PCa risk (OR = 3.65, 95% CI 2.26 to 5.91). The genetic risk score had an area under the ROC curve (AUROC) of 0.66 (95% CI 0.63 to 0.68). When adding the environmental score and family history to the genetic risk score, the AUROC increased by 0.05, reaching 0.71 (95% CI 0.69 to 0.74). Genetic susceptibility has a stronger risk value of the prediction that modifiable risk factors. While the added value of each SNP is small, the combination of 56 SNPs adds to the predictive ability of the risk model.

Association Between Socioeconomic Status and Tumor Grade Among Black Men with Prostate Cancer

BACKGROUND

Prostate cancer affects black men disproportionately. Black men have an increased incidence of prostate cancer diagnoses at earlier ages and higher grade as indicated by Gleason score, compared to other races. This study investigates the impact of socioeconomic status (SES) on prostate cancer tumor grade among black men.

METHODS

Black men with a prostate cancer diagnosis during 1973-2011 were examined using individual-level data from the SEER NLMS database. Logistic regression model estimated the likelihood of receiving a diagnosis of high versus low grade prostate cancer based on self-reported SES status at the time of diagnosis.

RESULTS

Men who completed high school only were statistically significantly more likely to have a higher prostate cancer grade than those with a bachelor's degree or higher. However, there was no dose-response effect across educational strata. Retirees were 30% less likely to have higher grade tumors compared to those who were employed.

CONCLUSIONS

SES differences among black men did not fully explain the high grade of prostate cancer. Further research is needed on the biology of the disease and to assess access to medical care and prostate health education, discrimination, stress exposures, and social norms that might contribute to the aggressiveness of prostate cancer among black men.

What Are the Links of Prostate Cancer with Physical Activity and Nutrition? : A Systematic Review Article

BACKGROUND

Prostate cancer (PCa) is the second most common malignancy in men worldwide. The purpose of this study was to provide a brief synthesis the current knowledge for the effects of physical activity (PA) and nutrition on PCa risk.

METHODS

A systematic review of English languages reviews, meta-analysis, and original articles published from 2009 to 2015 extracted from the following websites: MEDLINE, Web of Science, Health Source, Science Direct, and their references.

RESULTS

The review of the literature led to the selection of 12 review or meta-analysis studies and 15 lately published observational studies. Most of studies reported relationship of recreational and occupational PA and vegetables, fruits, vitamins, red/processed meats, and fats consumption with risk of PCa. Decreased risk for PCa associated with exercise was reported in seven of the ten articles on this topic. The inverse association of vegetables and/or fruit intake with PCa risk was reported in eight of 13 papers. The effect of meat/fat intake on PCa was estimated in four articles finding increased risk. There was heterogeneity between studies, and findings are inconsistent.

CONCLUSION

Physical activity does not significantly reduce the risk of PCa; however, vigorous exercise may reduce the risk of aggressive tumor. Besides, there is a lack of definitive evidence supporting the preventive role of diet against PCa. Due to many other benefits of regular moderate-vigorous PA and a diet high in vegetables and fruits and low in red/processed meats and fats, these lifestyle patterns may be recommended.

Diet, body size, physical activity and risk of prostate cancer: An umbrella review of the evidence

The existing literature on the relationship between diet, body size, physical activity and prostate cancer risk was summarised by the World Cancer Research Fund Continuous Update Project (CUP). An evaluation of the robustness of this evidence is required to help inform public health policy. The robustness of this evidence was evaluated using several criteria addressing evidence strength and validity, including the statistical significance of the random effects summary estimate and of the largest study in a meta-analysis, number of prostate cancer cases, between-study heterogeneity, 95% prediction intervals, small-study effects bias, excess significance bias and sensitivity analyses with credibility ceilings. A total of 248 meta-analyses were extracted from the CUP, which studied associations of 23 foods, 31 nutrients, eight indices of body size and three indices of physical activity with risk of total prostate cancer development, mortality or cancer development by stage and grade. Of the 176 meta-analyses using a continuous scale to measure the exposures, no association presented strong evidence by satisfying all the aforementioned criteria. Only the association of height with total prostate cancer incidence and mortality presented highly suggestive evidence with a 4% higher risk per 5 cm greater height (95% confidence interval, 1.03, 1.05). Associations for body mass index, weight, height, dietary calcium and spirits intake were supported by suggestive evidence. Overall, the association of diet, body size, physical activity and prostate cancer has been extensively studied, but no association was graded with strong evidence.

Coffee and cancer risk: A meta-analysis of prospective observational studies

Meta-analyses on coffee and cancer incidence mainly restricted to limited cancers. We carried out a more comprehensive meta-analysis of cohort studies to explore association between coffee and most cancer types. We conducted comprehensive search and summarized relative risk (RR) and 95% confidence intervals for the highest versus lowest coffee intake and cancer using STATA12. We conducted dose-analysis if result suggested significant association. The publication bias was evaluated with begg's and egger's test. Finally, 105 individual prospective studies were included. Inverse associations were observed on oral, pharyngeal, colon, liver, prostate, endometrial cancer and melanoma, with RR 0.69 (95% CI = 0.48-0.99, I² = 73.4%, P = 0.044), 0.87 (95% CI = 0.78-0.96, I² = 28.4%, P = 0.007), 0.46 (95% CI = 0.37-0.57, I² = 0%, P = 0), 0.89 (95% CI = 0.84-0.93, I² = 30.3%, P = 0.003), 0.73 (95% CI = 0.67-0.80, I²  = 0%, P = 0) and 0.89 (95% CI = 0.80-0.99, I²  = 0%, P = 0.031) respectively. However, the relative risk for lung cancer is 2.18 (95% CI = 1.26-3.75, I²  = 63.3%, P = 0.005). The summary relative risk for increment of 2 cups of coffee were RR = 0.73, 95% CI = 0.67-0.79 for liver cancer, RR = 0.97, 95% CI = 0.96-0.98 for prostate cancer and RR = 0.88, 95% CI = 0.85-0.92 for endometrial cancer. Accordingly, coffee intake was associated with reduced risk of oral, pharynx, liver, colon, prostate, endometrial cancer and melanoma and increased lung cancer risk.

Role of vitamin D receptor gene Cdx2 and Apa1 polymorphisms in prostate cancer susceptibility: a meta-analysis

BACKGROUND

Vitamin D receptor (VDR) gene polymorphisms affect the risk of prostate cancer. However, studies investigating the relationship between VDR gene polymorphisms (Cdx2 and ApaI) and prostate cancer risk are equivocal. Therefore, we conducted a meta-analysis of all the studies to review the evidence available.

METHODS

A comprehensive search of PubMed, EMBASE, and ISI Web of Science for studies published until September 2015 was conducted. Odds ratios (ORs) and 95 % confidence intervals (CIs) were analyzed to determine the association between VDR Cdx2 and ApaI polymorphisms, and prostate cancer risk.

RESULTS

The meta-analysis included 10 studies involving 4979 cases and 4380 controls to analyze the VDR Cdx2 polymorphism. An additional 11 studies involving 2837 cases and 2884 controls were analyzed for the VDR ApaI polymorphism. Evidence failed to support the role of VDR Cdx2 and ApaI polymorphisms in prostate cancer. For Cdx2, the pooled OR was 1.11 (95 % CI = 0.93-1.33) for AA vs. GG genotypes, 0.97 (95 % CI = 0.88-1.06) for GA vs. AA genotypes, 0.99 (95 % CI = 0.91-1.08) for AA + GA vs. GG, and 1.12 (95 % CI = 0.95-1.31) for AA vs. GA + GG. No significant relationship was observed in any subgroup analysis based on ethnicity, controls, and Hardy-Weinberg equilibrium (HWE). ORs for the ApaI polymorphism were similar.

CONCLUSIONS

VDR Cdx2 and ApaI polymorphisms are not associated with prostate cancer. Additional evidence is required to confirm this conclusion.

Common medications and prostate cancer mortality: a review

PURPOSE

Most prostate cancer patients also have comorbidities that are treated with both prescription and nonprescription medications; furthermore, many use dietary supplements. We assess their association with prognosis after prostate cancer diagnosis, and we discuss methodological challenges and clinical implications.

METHODS

We reviewed high-quality observational studies investigating the association of commonly used medications and supplements with prostate cancer-specific mortality.

RESULTS

There is preliminary evidence that statins and metformin use may be associated with lower risk of cancer-specific mortality after prostate cancer diagnosis; conversely, high calcium and multivitamin supplementation may be associated with increased risk. Evidence is inconclusive for nonsteroidal anti-inflammatory drugs, acetylsalicylic acid (aspirin), insulin, antihypertensives such as angiotensin-converting enzyme inhibitors and beta-blockers, digoxin, and warfarin. Common limitations of the internal validity of studies examined include unmeasured confounding and confounding by indication, competing risks, and time-related biases such as immortal time bias. The majority of studies focused on Caucasian men with specific comorbidities, while heterogeneity among patients and tumors was mostly not assessed.

CONCLUSIONS

Commonly prescribed medications and over-the-counter supplements may influence prognosis among prostate cancer patients. Further well-designed pharmacoepidemiologic studies and randomized controlled trials of selected medications in appropriate patient groups are necessary before these drugs can bear new indications for prostate cancer treatment. We discuss considerations when deciding about use of these drugs in clinical practice at the present time.

Ginger augmented chemotherapy: A novel multitarget nontoxic approach for cancer management

Cancer, referred to as the 'disease of civilization', continues to haunt humanity due to its dreadful manifestations and limited success of therapeutic interventions such as chemotherapy in curing the disease. Although effective, chemotherapy has repeatedly demonstrated inadequacy in disease management due to its debilitating side effects arising from its deleterious nonspecific effects on normal healthy cells. In addition, development of chemoresistance due to mono-targeting often results in cessation of chemotherapy. This urgently demands development and implementation of multitargeted alternative therapies with mild or no side effects. One extremely promising strategy that yet remains untapped in the clinic is augmenting chemotherapy with dietary phytochemicals or extracts. Ginger, depository of numerous bioactive molecules, not only targets cancer cells but can also mitigate chemotherapy-associated side effects. Consequently, combination therapy involving ginger extract and chemotherapeutic agents may offer the advantage of being efficacious with reduced toxicity. Here we discuss the remarkable and often overlooked potential of ginger extract to manage cancer, the possibility of developing ginger-based combinational therapies, and the major roadblocks along with strategies to overcome them in clinical translation of such inventions. We are optimistic that clinical implementation of such combination regimens would be a much sought after modality in cancer management.

Metabolomic Biomarkers of Prostate Cancer: Prediction, Diagnosis, Progression, Prognosis, and Recurrence

Metabolite profiling is being increasing employed in the study of prostate cancer as a means of identifying predictive, diagnostic, and prognostic biomarkers. This review provides a summary and critique of the current literature. Thirty-three human case-control studies of prostate cancer exploring disease prediction, diagnosis, progression, or treatment response were identified. All but one demonstrated the ability of metabolite profiling to distinguish cancer from benign, tumor aggressiveness, cases who recurred, and those who responded well to therapy. In the subset of studies where biomarker discriminatory ability was quantified, high AUCs were reported that would potentially outperform the current gold standards in diagnosis, prognosis, and disease recurrence, including PSA testing. There were substantial similarities between the metabolites and the associated pathways reported as significant by independent studies, and important roles for abnormal cell growth, intensive cell proliferation, and dysregulation of lipid metabolism were highlighted. The weight of the evidence therefore suggests metabolic alterations specific to prostate carcinogenesis and progression that may represent potential metabolic biomarkers. However, replication and validation of the most promising biomarkers is currently lacking and a number of outstanding methodologic issues remain to be addressed to maximize the utility of metabolomics in the study of prostate cancer. Cancer Epidemiol Biomarkers Prev; 25(6); 887-906. ©2016 AACR.

Ejaculation Frequency and Risk of Prostate Cancer: Updated Results with an Additional Decade of Follow-up

BACKGROUND

Evidence suggests that ejaculation frequency may be inversely related to the risk of prostate cancer (PCa), a disease for which few modifiable risk factors have been identified.

OBJECTIVE

To incorporate an additional 10 yr of follow-up into an original analysis and to comprehensively evaluate the association between ejaculation frequency and PCa, accounting for screening, clinically relevant disease subgroups, and the impact of mortality from other causes.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study of participants in the Health Professionals Follow-up Study utilizing self-reported data on average monthly ejaculation frequency. The study includes 31925 men who answered questions on ejaculation frequency on a 1992 questionnaire and followed through to 2010. The average monthly ejaculation frequency was assessed at three time points: age 20-29 yr, age 40-49 yr, and the year before questionnaire distribution.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Incidence of total PCa and clinically relevant disease subgroups. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS AND LIMITATIONS

During 480831 person-years, 3839 men were diagnosed with PCa. Ejaculation frequency at age 40-49 yr was positively associated with age-standardized body mass index, physical activity, divorce, history of sexually transmitted infections, and consumption of total calories and alcohol. Prostate-specific antigen (PSA) test utilization by 2008, number of PSA tests, and frequency of prostate biopsy were similar across frequency categories. In multivariable analyses, the hazard ratio for PCa incidence for ≥21 compared to 4-7 ejaculations per month was 0.81 (95% confidence interval [CI] 0.72-0.92; p<0.0001 for trend) for frequency at age 20-29 yr and 0.78 (95% CI 0.69-0.89; p<0.0001 for trend) for frequency at age 40-49 yr. Associations were driven by low-risk disease, were similar when restricted to a PSA-screened cohort, and were unlikely to be explained by competing causes of death.

CONCLUSIONS

These findings provide additional evidence of a beneficial role of more frequent ejaculation throughout adult life in the etiology of PCa, particularly for low-risk disease.

PATIENT SUMMARY

We evaluated whether ejaculation frequency throughout adulthood is related to prostate cancer risk in a large US-based study. We found that men reporting higher compared to lower ejaculatory frequency in adulthood were less likely to be subsequently diagnosed with prostate cancer.

Association between preoperative serum total cholesterol level and biochemical recurrence in prostate cancer patients who underwent radical prostatectomy

The aim of this study was to investigate the association between serum total cholesterol (TC) level and biochemical recurrence (BCR) following radical prostatectomy (RP). The study included 562 patients with T1-3N0M0 prostate cancer, who underwent RP at our institution between 2002 and 2010. No patients received neoadjuvant and/or adjuvant therapy. The associations between preoperative TC level, clinicopathological factors and BCR were assessed using univariate and multivariate analyses. During follow-up (mean, 54.0 months), 168 patients (168/562, 29.9%) experienced BCR, with a 5-year BCR-free rate of 67.2%. Of the clinicopathological characteristics investigated, statin use and lymphovascular invasion (LVI) status were associated with lower TC level (P=0.003 and P=0.014, respectively). In the univariate analysis, a higher serum prostate-specific antigen (PSA) level at diagnosis, extracapsular extension, positive surgical margin, seminal vesicle invasion, LVI, perineural invasion, higher Gleason score (GS ≥8) based on the RP specimen, increased body mass index, and low preoperative TC level, were significantly associated with BCR. In the multivariate analysis, the TC level was an independent predictor of BCR (hazard ratio = 0.925 per 10 mg/dl; 95% confidence interval: 0.879-0.973; P=0.003), as was the serum PSA level, extracapsular extension, positive surgical margin and the GS. Low preoperative serum TC levels were associated with an increased risk of BCR among prostate cancer patients who underwent RP. Our findings suggest that the preoperative serum TC level may provide important clinical information that may prove to be useful in patient counseling.

MiRNA 34a: a therapeutic target for castration-resistant prostate cancer

INTRODUCTION

Development of a therapy for bone metastases is of paramount importance for castration-resistant prostate cancer (CRPC). The osteomimetic properties of CRPC confer a propensity to metastasize to osseous sites. Micro-ribonucleic acid (miRNA) is non-coding RNA that acts as a post-transcriptional regulator of multiple proteins and associated pathways. Therefore identification of miRNAs could reveal a valid third generation therapy for CRPC.

AREAS COVERED

miR34a has been found to play an integral role in the progression of prostate cancer, particularly in the regulation of metastatic genes involved in migration, intravasation, extravasation, bone attachment and bone homeostasis. The correlation between miR34a down-regulation and metastatic progression has generated substantial interest in this field.

EXPERT OPINION

Examination of the evidence reveals that miR34a is an ideal target for gene therapy for metastatic CRPC. We also conclude that future studies should focus on the effects of miR34a upregulation in CRPC with respect to migration, translocation to bone micro-environment and osteomimetic phenotype development. The success of miR34a as a therapeutic is reliant on the development of appropriate delivery systems and targeting to the bone micro-environment. In tandem with any therapeutic studies, biomarker serum levels should also be ascertained as an indicator of successful miR34a delivery.

Development and Application of a Lifestyle Score for Prevention of Lethal Prostate Cancer

BACKGROUND

Several lifestyle factors have been associated with risk of lethal prostate cancer, but little is known about their combined effect. Our objective was to develop and apply a lifestyle score for prevention of lethal prostate cancer.

METHODS

We developed a lifestyle score among 42 701 men in the Health Professionals Follow-up Study (HPFS) followed from 1986 to 2010 and applied it among 20 324 men in the Physicians' Health Study (PHS) followed from 1982 to 2010. One point was given for each of: not currently smoking or quit 10 or more years ago, body mass index under 30 kg/m(2), high vigorous physical activity, high intake of tomatoes and fatty fish, and low intake of processed meat. Diet-only scores (range = 0-3) and total scores (range = 0-6) were calculated. We used multivariable Cox proportional hazards regression to estimate the risk of lethal prostate cancer, adjusting for potential risk factors of lethal prostate cancer. All statistical tests were two-sided.

RESULTS

We observed 576 lethal prostate cancer events in HPFS and 337 in PHS. Men with 5-6 vs 0-1 points had a 68% decreased risk of lethal prostate cancer (hazard ratio [HR] = 0.32, 95% confidence interval [CI] = 0.19 to 0.52) in HPFS and a non-statistically significant 38% decreased risk (HR = 0.62, 95% CI = 0.30 to 1.26) in PHS. For dietary factors only, men with 3 vs 0 points had a 46% decreased risk (HR = 0.54, 95% CI = 0.30 to 0.96) in the HPFS and a non-statistically significant 30% decreased risk (HR = 0.70, 95% CI = 0.40 to 1.23) in PHS.

CONCLUSIONS

Adhering to a healthy lifestyle, defined by not smoking, normal body weight, high physical activity, and a healthy diet, may lower risk of lethal prostate cancer.

Germline genetic profiling in prostate cancer: latest developments and potential clinical applications

Familial and twin studies have demonstrated a significant inherited component to prostate cancer predisposition. Genome wide association studies have shown that there are 100 single nucleotide polymorphisms which have been associated with the development of prostate cancer. This review aims to discuss the scientific methods used to identify these susceptibility loci. It will also examine the current clinical utility of these loci, which include the development of risk models as well as predicting treatment efficacy and toxicity. In order to refine the clinical utility of the susceptibility loci, international consortia have been developed to combine statistical power as well as skills and knowledge to further develop models that could be used to predict risk and treatment outcomes.

Sleep Duration and Disruption and Prostate Cancer Risk: a 23-Year Prospective Study

BACKGROUND

Sleep deficiency is a major public health problem. There are limited human data on whether sleep duration or disruption are risk factors for prostate cancer.

METHODS

We prospectively followed 32,141 men in the Health Professionals Follow-Up Study who reported their typical sleep duration in 1987, 2000, and 2008. We identified 4,261 incident prostate cancer cases, including 563 lethal cases through 2010. Sleep disruption was assessed in 2004 among 19,639 men, with 930 prostate cancer cases (50 lethal) identified from 2004 to 2010. Cox proportional hazards models were used to evaluate the association between sleep insufficiency and risk of overall and lethal prostate cancer.

RESULTS

In 1987, 2% of men reported sleeping ≤5 hours per night. We found no association between habitual sleep duration or change in sleep duration with the risk of advanced or lethal prostate cancer. We also found no association between waking up during the night, difficulty falling asleep, or waking up too early, and risk of prostate cancer. In 2004, 6% of men reported never feeling rested when they woke up; these men had an increased risk of developing lethal prostate cancer compared with those who reported always feeling rested when they woke up (RR, 3.05; 95% CI, 1.15-8.10).

CONCLUSIONS

We found no consistent association between self-reported sleep duration or sleep disruption and any of our prostate cancer outcomes.

IMPACT

We did not find support for a consistent association between self-reported sleep and risk of advanced or lethal prostate cancer in this large cohort of men.

Linking obesogenic dysregulation to prostate cancer progression

The global epidemic of obesity is closely linked to the development of serious co-morbidities, including many forms of cancer. Epidemiological evidence consistently shows that obesity is associated with a similar or mildly increased incidence of prostate cancer but, more prominently, an increased risk for aggressive prostate cancer and prostate cancer-specific mortality. Studies in mice demonstrate that obesity induced by high-fat feeding increases prostate cancer progression; however, the mechanisms underpinning this relationship remain incompletely understood. Adipose tissue expansion in obesity leads to local tissue dysfunction and is associated with low-grade inflammation, alterations in endocrine function and changes in lipolysis that result in increased delivery of fatty acids to tissues of the body. The human prostate gland is covered anteriorly by the prominent peri-prostatic adipose tissue and laterally by smaller adipose tissue depots that lie directly adjacent to the prostatic surface. We discuss how the close association between dysfunctional adipose tissue and prostate epithelial cells might result in bi-directional communication to cause increased prostate cancer aggressiveness and progression. However, the literature indicates that several 'mainstream' hypotheses regarding obesity-related drivers of prostate cancer progression are not yet supported by a solid evidence base and, in particular, are not supported by experiments using human tissue. Understanding the links between obesity and prostate cancer will have major implications for the health policy for men with prostate cancer and the development of new therapeutic or preventative strategies.

Prostate cancer risk among users of digoxin and other antiarrhythmic drugs in the Finnish Prostate Cancer Screening Trial

PURPOSE

Long-term usage of the antiarrhythmic drug digoxin has been connected to lowered risk of prostate cancer. A recent study has suggested that beta-blockers might also have similar risk-decreasing effects. We evaluated the association between use of digoxin, beta-blocker sotalol, and other antiarrhythmic drugs and prostate cancer risk in a retrospective cohort study.

METHODS

Our study population consisted of men in the Finnish Prostate Cancer Screening Trial during 1996-2012 (n = 78,615). During median follow-up of 12 years, 6,639 prostate cancer cases were diagnosed. The national prescription database was the source of the information of antiarrhythmic drug purchases. Data were analyzed using Cox regression method with medication use as a time-dependent variable.

RESULTS

No association was found for overall prostate cancer risk with antiarrhythmic drug use (HR 1.05 95% CI 0.94-1.18). Neither sotalol (HR 0.97 95% CI 0.76-1.24) nor digoxin (HR 1.01 95% CI 0.87-1.16) users had a decreased risk of prostate cancer. Similar results were obtained for high-grade (Gleason 7-10) and metastatic prostate cancer. Nevertheless, the risk estimates for Gleason 7-10 prostate cancer tended to decrease by duration of digoxin use (p for trend = 0.052), suggesting that the drug may reduce the risk in long-term usage (HR 0.71, 95% CI 0.49-1.03). In analysis stratified by screening trial arm, the protective association against Gleason 7-10 disease was observed only in the screening arm (HR 0.31, 95% CI 0.12-0.84 for men who had used digoxin for 5 years or longer).

CONCLUSION

Digoxin or other antiarrhythmic drugs are not associated with any clear decrease in prostate cancer risk. However, digoxin might have a benefit in long-term use by reducing risk of high-grade disease. Further research will be needed to evaluate possible effects on prostate cancer survival.

Role of diet in prostate cancer: the epigenetic link

Diet is hypothesized to be a critical environmentally related risk factor for prostate cancer (PCa) development, and specific diets and dietary components can also affect PCa progression; however, the mechanisms underlying these associations remain elusive. As for a maturing organism, PCa's epigenome is plastic and evolves from the pre-neoplastic to the metastatic stage. In particular, epigenetic remodeling relies on substrates or cofactors obtained from the diet. Here we review the evidence that bridges dietary modulation to alterations in the prostate epigenome. We propose that such diet-related effects offer a mechanistic link between the impact of different diets and the course of PCa development and progression.

Insufficient Sleep and Risk of Prostate Cancer in a Large Swedish Cohort

STUDY OBJECTIVE

There are some data to suggest that insufficient sleep, including short sleep duration and sleep disruption, may be associated with an increased risk of cancer. We investigated the association between sleep duration and sleep disruption and risk of prostate cancer.

DESIGN

Prospective cohort study.

SETTING

Sweden.

PARTICIPANTS

A total of 14,041 men in the Swedish National March Cohort.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Habitual sleep duration and sleep disruption were self-reported in 1997. Prostate cancer diagnoses, including lethal (metastases at diagnosis or death from prostate cancer) and advanced (stage T4, N1, or M1 at diagnosis or death from prostate cancer), were determined from linkage to nationwide cancer registries through 2010. We conducted Cox proportional hazards regression adjusted for potential confounding variables. During 13 years of follow-up, we identified 785 cases of incident prostate cancer, including 118 lethal and 127 advanced cases. Four percent of men reported sleeping 5 h or less a night, and 2% reported sleeping 9 h or more per night. We found no association between sleep duration and risk of prostate cancer overall or for advanced/lethal disease. We also did not find an association between prostate cancer and sleep disruption, as defined by difficulty falling asleep, difficulty maintaining sleep, sleep quality, and restorative power of sleep.

CONCLUSIONS

In this large prospective study from Sweden, we found no association between habitual sleep duration or sleep disruption and risk of prostate cancer.

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

Background

Epidemiologic studies have reported various results relating phytoestrogens to prostate cancer (PCa). The aim of this study was to provide a comprehensive meta-analysis on the extent of the possible association between phytoestrogens (including consumption and serum concentration) and the risk of PCa.

Methods

Eligible studies were retrieved via both computer searches and review of references. The summary relative risk ratio (RR) or odds ratio (OR) and 95 % confidence interval (CI) were calculated with random effects models.

Results

A total of 11 studies (2 cohort and 9 case–control studies) on phytoestrogen intake and 8 studies on serum concentration were included in the meta-analysis. The pooled odds ratio (OR) showed a significant influence of the highest phytoestrogens consumption (OR 0.80, 95 % CI 0.70–0.91) and serum concentration (OR 0.83, 95 % CI 0.70–0.99) on the risk of PCa. In stratified analysis, high genistein and daidzein intake and increased serum concentration of enterolactone were associated with a significant reduced risk of PCa. However, no significant associations were observed for isoflavone intake, lignans intake, or serum concentrations of genistein, daidzein, or equol.

Conclusions

The overall current literature suggests that phytoestrogen intake is associated with a decreased risk of PCa, especially genistein and daidzein intake. Increased serum concentration of enterolactone was also associated with a significant reduced risk of PCa. Further efforts should be made to clarify the underlying biological mechanisms.

Prediagnostic Obesity and Physical Inactivity Are Associated with Shorter Telomere Length in Prostate Stromal Cells

Obesity and inactivity have been associated with advanced-stage prostate cancer, and poor prostate cancer outcomes, though the underlying mechanism(s) is unknown. To determine whether telomere shortening, which has been associated with lethal prostate cancer, may be a potential underlying mechanism, we prospectively evaluated the association between measures of adiposity, physical activity, and telomere length in 596 participants in the Health Professionals Follow-up Study, who were surgically treated for prostate cancer. Using tissue microarrays, we measured telomere length in cancer and benign cells using a telomere-specific FISH assay. Adiposity and activity were assessed via questionnaire within 2 years of diagnosis. Adjusting for age, pathologic stage, and grade, the median and SD of the per cell telomere signals were determined for each man for stromal cells and cancer cells by adiposity and activity categories. Overweight/obese men (54%) were similar to normal weight men on most factors, but had higher Gleason sum and lower activity levels. Overweight/obese men had 7.4% shorter telomeres in stromal cells than normal weight men (P = 0.06). The least active men had shorter telomeres in stromal cells than more active men (Ptrend = 0.002). Men who were overweight/obese and the least active had the shortest telomeres in stromal cells (20.7% shorter; P = 0.0005) compared with normal weight men who were the most active. Cancer cell telomere length and telomere length variability did not differ by measures of adiposity or activity. Telomere shortening in prostate cells may be one mechanism through which lifestyle influences prostate cancer risk and outcomes.

Prostate cancer incidence, clinical stage and survival in relation to obesity: a prospective cohort study in Denmark

There is no clear link between obesity and prostate cancer incidence but an association has been reported between obesity and fatal prostate cancer. We report on two prospective cohort analyses on (i) the incidence of prostate cancer in relation to obesity in a cohort of men with no previous cancer, and on (ii) the stage distribution and prostate cancer specific mortality in relation to obesity among men with prostate cancer. The "Diet, Cancer and Health" prospective cohort study was established in Denmark in 1993-1997 and accrued 26,944 men aged 50-64 years. Data were extracted on height, weight, body mass index (BMI), waist circumference and body fat percentage. Information on cancer incidence and deaths were obtained by record linkage with the Danish Cancer Register and the Danish Death Register. The incidence rate of prostate cancer was similar or slightly lower in obese men compared with nonobese men, but obese men tended to be diagnosed with more advanced prostate cancer. The proportion of Stage 3-4 cancers was 37% in the lowest BMI quartile and 48% in the highest (p = 0.006). Obese men with prostate cancer had higher prostate cancer specific mortality. The hazard ratio comparing the highest and the lowest quartiles of BMI was 1.48 (95% confidence interval: 1.06-2.05; p-value for trend: 0.002). The association was attenuated but not eliminated by statistical adjustment for stage, and the data are suggestive of a stage-independent causal pathway where prostate cancer in obese men has higher fatality, even in early-stage disease.

A Perspective on Prostate Carcinogenesis and Chemoprevention

In this perspective, modifiable carcinogenic factors for the prostate are summarized. This is followed by a discussion of how current knowledge about causation of prostate cancer and chemoprevention of prostate cancer can be used to develop preventive strategies. Prostate cancer is a slowly developing cancer which offers opportunities for preventive interventions. Only a few randomized clinical trials of prostate cancer prevention have been completed. The SELECT study with selenium and vitamin E did not find protective effects, but in two trials with 5α-reductase inhibitors risk was reduced about 25%, showing that chemoprevention is possible and indicating that the androgen receptor is a suitable target. Besides smoking cessation and reduction of obesity, there are no known dietary or life style interventions that will have a major impact on prostate cancer risk. Inflammation of the prostate is an attractive target and aspirin may be a promising candidate agent, but has not been addressed yet in preclinical and clinical studies. Antioxidants other than selenium and vitamin E are unlikely to be very effective and data on several dietary supplements are not encouraging. More candidate agents need to be identified and tested in relevant and adequate preclinical models and Phase II trials that have predictive value for outcome of Phase III randomized studies. Doing this will require a systematic approach comparing preclinical and clinical study outcomes to determine their predictive value of preventive efficacy.

Coffee consumption and prostate cancer risk: a meta-analysis of cohort studies

This meta-analysis was conducted to assess the association between coffee consumption and prostate cancer risk. Thirteen cohort studies with 34,105 cases and 539,577 participants were included in the meta-analysis. The summary relative risks (RRs) with 95% confidence intervals (CIs) for different coffee intake levels were calculated. Dose-response relationship was assessed using generalized least square trend estimation. The pooled RR for the highest vs. lowest coffee intake was 0.90 (95% CI: 0.85-0.95), with no significant heterogeneity across studies (P = 0.267; I(2) = 17.5%). The dose-response analysis showed a lower cancer risk decreased by 2.5% (RR = 0.975; 95% CI: 0.957-0.995) for every 2 cups/day increment in coffee consumption. Stratifying by geographic region, there was a statistically significant protective influence of coffee on prostate cancer risk among European populations. In subgroup analysis of prostate cancer grade, the summary RRs were 0.89 (95% CI: 0.83-0.96) for nonadvanced, 0.82 (95% CI: 0.61-1.10) for advanced and 0.76 (95% CI: 0.55-1.06) for fatal diseases. Our findings suggest that coffee consumption may be associated with a reduced risk of prostate cancer and it also has an inverse association with nonadvanced prostate cancer. Because of the limited number of studies, more prospective studies with large sample size are needed to confirm this association.

Antiproliferative 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides, a new tubulin inhibitor chemotype

We discovered a new chemical class of antiproliferative agents, 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides. SAR-guided optimization of the two distinct terminal fragments yielded a compound with 120 nM potency in an antiproliferative assay. Biological activity profile studies (COMPARE analysis) demonstrated that 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides act as tubulin inhibitors, and this conclusion was confirmed via biochemical assays with pure tubulin and demonstration of increased numbers of mitotic cells following treatment of a leukemia cell line.

Dietary fat intake in relation to lethal breast cancer in two large prospective cohort studies

Whether fat intake influences risk of developing more aggressive, lethal breast tumors is unknown. We evaluated intakes of total fat, specific types of fat, and cholesterol prior to diagnosis in relation to lethal breast cancer risk in 88,759 women in the Nurses' Health Study (NHS; 1980-2010) and 93,912 women in the Nurses' Health Study II (NHSII; 1991-2010). Diet was assessed every 4 years using a semi-quantitative food frequency questionnaire. Breast cancers were confirmed with pathology reports; deaths were confirmed by next of kin or the National Death Index. We defined lethal cases as women with invasive breast cancer who died of breast cancer. We pooled the cohorts and used multivariable Cox proportional hazards models. We identified 1,529 lethal breast cancer cases (1,279 in NHS and 250 in NHSII). Higher total fat intake was associated with a slightly lower lethal breast cancer risk (top vs. bottom quintile hazard ratio [HR] 0.85; 95 % CI 0.72, 1.01; p trend = 0.05). Specific types of fat were generally not associated with lethal breast cancer risk. For example, compared with those in the lowest quintile of saturated fat intake, those in the highest quintile had a HR of 0.98 (95 % CI 0.75, 1.26; p trend = 0.96). Among women diagnosed with breast cancer, pre-diagnosis fat intake was not associated with survival. Higher pre-diagnosis fat intake was not associated with greater risk of lethal breast cancer in these large prospective cohort studies, consistent with the weight of the evidence against a causal role for fat intake and breast cancer incidence.

BMI is associated with larger index tumors and worse outcome after radical prostatectomy

BACKGROUND

To investigate the impact of body mass index (BMI) on tumor characteristics and biochemical recurrence (BCR) after radical prostatectomy (RP) for prostate cancer (PCa) in Japanese men.

METHODS

We evaluated data from consecutive patients who had undergone RP. Data analyzed included age, preoperative serum PSA, prostatic volume, BMI (continuous or categorized (≤ 25 kg/m(2)) values), clinical and pathological findings including index tumor volume (ITV), and current status in areas such as smoker or nonsmoker and presence or absence of diabetes. We analyzed association between BMI and BCR, especially based on ITV using univariate and multivariate analysis.

RESULTS

We analyzed data from a total of 703 patients. The median follow-up time was 38.4 months. BCR was diagnosed in 154 patients (21.9%) at a median of 9.7 months postoperatively. Multivariate linear regression analysis adjusted for preoperative variables showed a significant positive association between BMI and ITV (continuous BMI: P=0.002; categorical BMI: P<0.001, respectively), especially for higher-grade tumors (Gleason score ≥ 7). Cox proportional hazards analysis showed a significant association between continuous BMI and BCR after surgery (preoperative variables, hazard ratio (HR) 1.09, 95% confidence interval (CI) 1.02-1.16, P=0.008), independent of clinical and pathological findings. In patients with high-risk cancer, the positive association between BMI and BCR was strengthened (preoperative variables, continuous BMI, HR 1.16, 95% CI 1.07-1.26, P<0.001; categorical BMI, HR 2.11, 95% CI 1.29-3.45, P=0.003, respectively).

CONCLUSIONS

Greater BMI significantly correlates with higher rates of BCR after surgery; BMI is a preoperative variable associated with high-grade ITV. Our results suggest that the biological environment created by greater BMI may contribute to increasing tumor aggressiveness.

The heritability of prostate cancer in the Nordic Twin Study of Cancer

BACKGROUND

Prostate cancer is thought to be the most heritable cancer, although little is known about how this genetic contribution varies across age.

METHODS

To address this question, we undertook the world's largest prospective study in the Nordic Twin Study of Cancer cohort, including 18,680 monozygotic (MZ) and 30,054 dizygotic (DZ) same-sex male twin pairs. We incorporated time-to-event analyses to estimate the risk concordance and heritability while accounting for censoring and competing risks of death, essential sources of biases that have not been accounted for in previous twin studies modeling cancer risk and liability.

RESULTS

The cumulative risk of prostate cancer was similar to that of the background population. The cumulative risk for twins whose co-twin was diagnosed with prostate cancer was greater for MZ than for DZ twins across all ages. Among concordantly affected pairs, the time between diagnoses was significantly shorter for MZ than DZ pairs (median, 3.8 versus 6.5 years, respectively). Genetic differences contributed substantially to variation in both the risk and the liability [heritability = 58% (95% confidence interval, 52%-63%)] of developing prostate cancer. The relative contribution of genetic factors was constant across age through late life with substantial genetic heterogeneity even when diagnosis and screening procedures vary.

CONCLUSIONS

Results from the population-based twin cohort indicate a greater genetic contribution to the risk of developing prostate cancer when addressing sources of bias. The role of genetic factors is consistently high across age.

IMPACT

Findings affect the search for genetic and epigenetic markers and frame prevention efforts.

Sedentary behavior and prostate cancer risk in the NIH-AARP Diet and Health Study

Sedentary behavior (sitting time) has been proposed as an independent risk factor for some cancers; however, its role in the development of prostate cancer has not been determined. We examined the prospective associations of self-reported daily sitting time and daily television/video viewing time with the risk of developing or dying from prostate cancer among 170,481 men in the NIH-AARP Diet and Health Study. We estimated HRs and 95% confidence intervals (CI) using Cox proportional hazards regression. Between 1996 and 2006, there were 13,751 incident (including 1,365 advanced) prostate cancer cases identified; prostate cancer mortality (through 2008) was 669. No strong or significant association with prostate cancer risk was seen in fully adjusted models for either daily sitting or television/video time. There were some suggestions of effect modification by body mass index (BMI; interaction for television/video time and BMI, P = 0.02). For total prostate cancer risk, television/video time was associated with a slightly elevated, but nonsignificant, increase amongst obese men (HR = 1.28; 95% CI, 0.98-1.69); a null association was observed amongst overweight men (HR = 1.04; 0.89-1.22); and, for men with a normal BMI, television/video time was associated with a nonsignificant risk decrease (HR = 0.82; 95% CI, 0.66-1.01). Similar patterns were observed for total daily sitting and television/video time in advanced prostate cancer and prostate cancer mortality. Sedentary behavior seems to play a limited role in the development of prostate cancer; however, we cannot rule out potential effect modification by BMI or the impact of measurement error on results.

Tea consumption and prostate cancer: an updated meta-analysis

Objectives

Tea is supposed to have chemopreventive effect against various cancers. However, the protective role of tea in prostate cancer is still controversial. The aim of this study is to elucidate the association between tea consumption and prostate cancer risk by meta-analysis.

Methods

A total of 21 published articles were retrieved via both computerized searches and review of references. Estimates of OR/RR for highest versus non/lowest tea consumption levels were pooled on the basis of random effect model or fixed effect model as appropriate. Stratified analyses on tea type, population and study design were also conducted.

Results

No statistical significance was detected between tea consumption and prostate cancer risk in meta-analysis of all included studies (odds ratio (OR) = 0.86, 95% CI (0.69-1.04)). Furthermore, stratified analyses on population (Asian, OR = 0.81, 95% CI (0.55-1.08); non-Asian, OR = 0.89, 95% CI (0.72-1.07)) and tea type (green tea, OR = 0.79, 95% CI (0.43-1.14); black tea, OR = 0.88, 95% CI (0.73-1.02)) also yielded non-significant association. Only the case–control study subgroup demonstrated a borderline protective effect for tea consumption against prostate cancer (OR = 0.77, 95% CI (0.55-0.98)).

Conclusion

Our analyses did not support the conclusion that tea consumption could reduce prostate cancer risk. Further epidemiology studies are needed.

Nutrition, hormones and prostate cancer risk: results from the European prospective investigation into cancer and nutrition

Nutritional factors may influence the risk of developing prostate cancer, but understanding of this topic is poor. This chapter discusses research on this subject, mostly from the European Prospective Investigation into Cancer and Nutrition (EPIC), a cohort which includes 150,000 men recruited in the 1990s in eight European countries. So far the EPIC collaborators have published analyses of the relationship of prostate cancer risk with the intake of a range of foods and nutrients, and with blood-based markers of nutritional factors, on up to nearly 3,000 incident cases of prostate cancer. Most of the results of these analyses have been null, with no clear indication that the risk for prostate cancer is related to intakes of meat, fish, fruit, vegetables, fibre, fat or alcohol or with blood levels of fatty acids, carotenoids, tocopherols, B vitamins, vitamin D, or selenium. There is some evidence from EPIC that risk may be increased in men with a high intake of protein from dairy products, and analyses of hormone levels have shown that risk is higher in men with relatively high blood levels of insulin-like growth factor-I (IGF-I). More research is needed to better describe the relationships of prostate cancer risk with IGF-I and related hormones, and to better understand whether nutritional factors may influence risk through hormones or perhaps by other mechanisms.

The biology and natural history of prostate cancer: a short introduction

This chapter aims to serve as a quick glance outlining an overall picture of mainstream thoughts, and to serve as a point of departure for more thorough discussions. The introduction of PSA testing has immensely complicated research in prostate cancer epidemiology and biology and added new clinical and biological domains. As for many cancers, age and ethnic origin are the strongest known risk factors. While migrant studies imply that environment and/or personal life style is important, epidemiological studies have failed to establish any strong leads. Despite the known androgen dependence of prostate cancer, there is little to support that circulating levels of androgens, estrogens or 5-alpha-reductase are associated with risk of developing the disease. However, a consistent finding is a positive association with levels of Insulin-like Growth Factor-1 (IGF-1). Prostate cancer is one of the cancers most strongly related to inherited susceptibility, even when taking into account that family history of prostate cancer triggers PSA testing among relatives. A number of somatic genetic alterations (amplifications, deletions, point mutations, translocations) are associated with prostate cancer risk. Findings for alterations in FASN, HPN, AMACR and MYC have been fairly consistent. Recent research shows that the notion of "hormone-independent prostate cancer" has to be revised: most prostate cancers remain dependent on androgen receptor signalling also after progression despite traditional androgen deprivation therapy. Traditional markers of stage and type of disease still play a major role for prognostication and treatment decisions. Prostate cancer is one of the few cancers where patients have been recommended watchful waiting or active surveillance. This provides opportunities for studies of natural history of the disease. The understanding of prostate cancer aetiology and natural history has progressed slowly. However, the current situation is positively challenging and opens up possibilities for fruitful research.

Potential role of gastrointestinal microbiota composition in prostate cancer risk

Background

Among men in the U.S., prostate cancer is the most common cancer and the second leading cause of cancer death. Despite its prevalence, there are few established risk factors for prostate cancer. Some studies have found that intake of certain foods/nutrients may be associated with prostate cancer risk, but few have accounted for how intake and metabolic factors may interact to influence bioavailable nutrient levels and subsequent disease risk.

Presentation of the hypothesis

The composition of the gastrointestinal (GI) microbiome may influence metabolism of dietary compounds and nutrients (e.g., plant phenols, calcium, choline) that may be relevant to prostate cancer risk. We, therefore, propose the hypothesis that GI microbiota may have a markedly different composition among individuals with higher prostate cancer risk. These individuals could have microbial profiles that are conducive to intestinal inflammation and/or are less favorable for the metabolism and uptake of chemopreventive agents.

Testing the hypothesis

Because very little preliminary data exist on this potential association, a case–control study may provide valuable information on this topic. Such a study could evaluate whether the GI microbial profile is markedly different between three groups of individuals: healthy men, those with latent prostate cancer, and those with invasive prostate cancer. Any findings could then be validated in a larger study, designed to collect a series of specimens over time.

Implications of the hypothesis

Given the plethora of information emerging from the Human Microbiome Project, this is an opportune time to explore associations between the microbiome and complex human diseases. Identification of profiles that alter the host’s risk for disease may clarify inconsistencies in the literature on dietary factors and cancer risk, and could provide valuable targets for novel cancer prevention strategies.

[Pharmaco and diet based prostate cancer prevention]

In 2010, in France, 8,790 men died from prostate cancer despite a low and decreasing mortality rate. The individual risk/benefit ratio of prostate cancer screening is the focus of controversy and currently not in favor of a systematic screening program. Therefore, only prevention could reduce incidence, side effects of treatment and related mortality. Interestingly, prostate cancer prevention is also a field of controversy mainly about 5-alpha-reductase inhibitors. However, it could be expected that pharmaco- or diet-based prevention will be a huge tool for cancer control, even more for prostate cancer burden. This review comprehensively analyses which molecules or compounds could be used in preventive trials. With regard to pharmaco-prevention, three different kinds of drugs could be identified. First drugs, which aim at mainly or even solely reduce prostate cancer risk such as 5-alpha-reductase inhibitors and selective estrogen receptor modulators. Drugs, which aim at wider preventive impact such as: nonsteroidal anti-inflammatory drugs or difluoromethylornithine. Lastly, drugs for which reducing prostate cancer incidence is merely a side effect such as statins, metformin or histones desacetylase inhibitors. With regard to diet-based prevention, two main approaches could be identified: aliments and nutriments, on one hand, and vitamin and minerals, on the other. Interestingly if compounds reach experimental plausibility, natural foods or even global diet seem to have a higher impact. Lastly, besides assessment of efficacy, effectiveness required the critical step of compliance, which might actually be the weakest link of the prevention chain.

Diet, obesity, and cancer progression: are adipocytes the link?

Obesity has been linked to more aggressive characteristics of several cancers, including breast and prostate cancer. Adipose tissue appears to contribute to paracrine interactions in the tumor microenvironment. In particular, cancer-associated adipocytes interact reciprocally with cancer cells and influence cancer progression. Adipokines secreted from adipocytes likely form a key component of the paracrine signaling in the tumor microenvironment. In vitro coculture models allow for the assessment of specific adipokines in this interaction. Furthermore, micronutrients and macronutrients present in the diet may alter the secretion of adipokines from adipocytes. The effect of dietary fat and specific fatty acids on cancer progression in several in vivo model systems and cancer types is reviewed. The more common approaches of caloric restriction or diet-induced obesity in animal models establish that such dietary changes modulate tumor biology. This review seeks to explore available evidence regarding how diet may modulate tumor characteristics through changes in the role of adipocytes in the tumor microenvironment.

Coffee consumption and the risk of overall and fatal prostate cancer in the NIH-AARP Diet and Health Study

PURPOSE

Evidence on the association between coffee consumption and prostate cancer risk is inconsistent; furthermore, few studies have examined the relationship between coffee consumption and fatal prostate cancer. The aim of this study was to investigate whether coffee intake is associated with the risk of overall and fatal prostate cancer.

METHODS

We conducted a prospective analysis among 288,391 men in the National Institutes of Health AARP Diet and Health Study who were between 50 and 71 years old at baseline in 1995-1996. Coffee consumption was assessed at baseline. Cox proportional hazards models were used to calculate the age- and multivariable-adjusted hazard ratios (HR)s and 95 % confidence intervals (CIs).

RESULTS

Over 11 years of follow-up, 23,335 cases of prostate cancer were ascertained, including 2,927 advanced and 917 fatal cases. Coffee consumption was not significantly associated with prostate cancer risk. The multivariable-adjusted HRs (95 % CI), comparing those who drank six or more cups per day to nondrinker, were as follows: 0.94 (0.86-1.02), p trend = 0.08 for overall prostate cancer, 1.13 (0.91-1.40), p trend = 0.62 for advanced prostate cancer, and 0.79 (0.53-1.17), p trend = 0.20 for fatal prostate cancer. The findings remained nonsignificant when we stratified by prostate-specific antigen testing history or restricted to nonsmokers.

CONCLUSIONS

We found no statistically significant association between coffee consumption and the risk of overall, advanced, or fatal prostate cancer in this cohort, though a modest reduction in risk could not be excluded.

Potential of probiotics, prebiotics and synbiotics for management of colorectal cancer

Colorectal Cancer (CRC) is the second leading cause of cancer-related mortality and is the fourth most common malignant neoplasm in USA. Escaping apoptosis and cell mutation are the prime hallmarks of cancer. It is apparent that balancing the network between DNA damage and DNA repair is critical in preventing carcinogenesis. One-third of cancers might be prevented by nutritious healthy diet, maintaining healthy weight and physical activity. In this review, an attempt is made to abridge the role of carcinogen in colorectal cancer establishment and prognosis, where special attention has been paid to food-borne mutagens and functional role of beneficial human gut microbiome in evading cancer. Further the significance of tailor-made prebiotics, probiotics and synbiotics in cancer management by bio-antimutagenic and desmutagenic activity has been elaborated. Probiotic bacteria are live microorganisms that, when administered in adequate amounts, confer a healthy benefit on the host. Prebiotics are a selectively fermentable non-digestible oligosaccharide or ingredient that brings specific changes, both in the composition and/or activity of the gastrointestinal microflora, conferring health benefits. Synbiotics are a combination of probiotic bacteria and the growth promoting prebiotic ingredients that purport "synergism."

Selenium and prostate cancer prevention: insights from the selenium and vitamin E cancer prevention trial (SELECT)

The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was conducted to assess the efficacy of selenium and vitamin E alone, and in combination, on the incidence of prostate cancer. This randomized, double-blind, placebo-controlled, 2 × 2 factorial design clinical trial found that neither selenium nor vitamin E reduced the incidence of prostate cancer after seven years and that vitamin E was associated with a 17% increased risk of prostate cancer compared to placebo. The null result was surprising given the strong preclinical and clinical evidence suggesting chemopreventive activity of selenium. Potential explanations for the null findings include the agent formulation and dose, the characteristics of the cohort, and the study design. It is likely that only specific subpopulations may benefit from selenium supplementation; therefore, future studies should consider the baseline selenium status of the participants, age of the cohort, and genotype of specific selenoproteins, among other characteristics, in order to determine the activity of selenium in cancer prevention.

Nanoformulation of natural products for prevention and therapy of prostate cancer

There is a need for developing improved therapeutic options for the management of prostate cancer, able to inhibit proliferation of precancerous and malignant lesions and/or to improve the effectiveness of conventional chemopreventive and chemotherapeutic agents. In this perspective, application of nanotechnology based strategies for the delivery of natural compounds for effective management of the disease is being actively researched. Here, after highlighting the most promising natural compounds for chemoprevention and chemotherapy of prostate cancer, the state of the art nanotherapeutics and the recent proof-of-concept of "nanochemoprevention", as well as the clinical development of promising targeted nanoprototypes for use in the prostate cancer treatment are being discussed.