Sexually transmitted diseases and other urogenital conditions as risk factors for prostate cancer: a case–control study in Wayne County, Michigan

Sexually and non-sexually transmitted infections and the risk of prostate cancer: Results from the EPICAP study

INTRODUCTION

Prostate cancer (PCa) is by far the most common type of cancer among men in western countries. However, relatively little is known about its etiology despite the high morbidity and mortality. It has been suggested that chronic inflammation may be involved in prostate carcinogenesis. We investigated the role of sexually and non-sexually transmitted infections in prostate cancer risk with a specific interest in the aggressive types.

METHODS

We used data from epidemiological study of prostate cancer (EPICAP), a population-based case-control study. A total of 819 incident cases and 879 controls were interviewed face-to-face using a standardized questionnaire gathering information on known or suspected risk factors of prostate cancer and personal history of specific sexually and non-sexually transmitted infections: gonorrhea, syphilis, trichomonas, herpes, mononucleosis, Epstein-Barr virus, varicella-zoster, and dengue. Odds ratios (OR) and their 95% confidence interval were estimated using multivariate unconditional logistic regression.

RESULTS

There was no significant association between gonorrhea (OR: 0.90, 95% CI: 0.61-1.33), trichomonas (OR: 0.74, 95% CI: 0.27-2.07), genital herpes (OR: 0.69, 95% CI: 0.38-1.27), and the risk of prostate cancer. No association emerged for overall sexually transmitted bacterial and viral infections (OR 1.05, 95% CI: 0.86-1.29) and overall non-sexually transmitted viral infections (OR 1.11, 95% CI: 0.90-1.35) and the risk of prostate cancer.

CONCLUSION

Our results showed that sexually or non-sexually transmitted infections, either bacterial or viral, were not associated to prostate cancer. Therefore, further investigation is needed to help advance our understanding of the role of chronic inflammation in the etiology of prostate cancer, with a particular focus on its most aggressive types.

A matched case-control study in Taiwan to evaluate potential risk factors for prostate cancer

The rising incidence rate of prostate cancer (PCa) worldwide has become a public health concern. PCa has a multifactorial etiology, and the link between human papillomavirus (HPV) and PCa has been widely investigated by numerous case-control studies. This age-matched, case-control study included 143 PCa patients and 135 benign prostatic hyperplasia (BPH) patients, with prostatic specimens testing negative for malignancy, as control. Study participants were recruited from four major hospitals in Taoyuan City, Taiwan, period 2018-2020, looking into HPV infection and other PCa risk factors, including dietary habits, family history, personal lifestyle, and sexual behavior. Multiple logistic regression analysis and forward stepwise selection analysis were conducted to identify potential risk factors for PCa. HPV DNA was found in 10 of the 143 PCa cases (7%) and 2 of the 135 BPH controls (1.5%) (OR = 6.02, 95% CI = 1.03-30.3, p = 0.046). This association was slightly significant, and furthermore, high risk HPV was not found to be associated with PCa. Higher body mass index (BMI) (OR = 1.15, 95% CI = 1.05-1.27, p = 0.003), more total meat consumption (OR = 2.74, 95% CI = 1.26-5.94, p = 0.011), exhibited association to PCa. However, PCa family history only presented a statistically significant difference by forward stepwise analysis (OR = 3.91, 95% CI = 1.17-13.12, p = 0.027). While much focus has been on the association between HPV and PCa, the results of this study indicate that more efforts should be directed towards investigating dietary habits, personal lifestyle and family history as factors for PCa. These results could serve as a basis for designing PCa prevention strategies.

Microbiome and Prostate Cancer: A Novel Target for Prevention and Treatment

Growing evidence of the microbiome's role in human health and disease has emerged since the creation of the Human Microbiome Project. Recent studies suggest that alterations in microbiota composition (dysbiosis) may play an essential role in the occurrence, development, and prognosis of prostate cancer (PCa), which remains the second most frequent male malignancy worldwide. Current advances in biological technologies, such as high-throughput sequencing, transcriptomics, and metabolomics, have enabled research on the gut, urinary, and intra-prostate microbiome signature and the correlation with local and systemic inflammation, host immunity response, and PCa progression. Several microbial species and their metabolites facilitate PCa insurgence through genotoxin-mediated mutagenesis or by driving tumor-promoting inflammation and dysfunctional immunosurveillance. However, the impact of the microbiome on PCa development, progression, and response to treatment is complex and needs to be fully understood. This review addresses the current knowledge on the host-microbe interaction and the risk of PCa, providing novel insights into the intraprostatic, gut, and urinary microbiome mechanisms leading to PCa carcinogenesis and treatment response. In this paper, we provide a detailed overview of diet changes, gut microbiome, and emerging therapeutic approaches related to the microbiome and PCa. Further investigation on the prostate-related microbiome and large-scale clinical trials testing the efficacy of microbiota modulation approaches may improve patient outcomes while fulfilling the literature gap of microbial-immune-cancer-cell mechanistic interactions.

Vasectomy and Risk of Prostate Cancer: A Systematic Review and Meta-analysis

Context

Previous reports have shown an association between vasectomy and prostate cancer (PCa). However, there exist significant discrepancies between studies and systematic reviews due to a lack of strong causal association and residual confounding factors such as prostate-specific antigen (PSA) screening.

Objective

To assess the association between vasectomy and PCa, in both unadjusted and PSA screen-adjusted studies.

Evidence acquisition

We performed a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The PubMed, Scopus, and Web of Science databases were searched in January 2022 for studies that analyzed the association between vasectomy and PCa.

Evidence synthesis

A total of 37 studies including 16 931 805 patients met our inclusion criteria. A pooled analysis from all studies showed a significant association between vasectomy and any-grade PCa (odds ratio [OR] 1.23; 95% confidence interval [CI], 1.10–1.37; p < 0.001; I² = 96%), localized PCa (OR 1.08; 95% CI, 1.06–1.11; p < 0.00001; I² = 31%), or advanced PCa (OR 1.07; 95% CI, 1.02–1.13; p = 0.006; I² = 0%). The association with PCa remained significant when the analyses were restricted to studies with a low risk of bias (OR 1.06; 95% CI, 1.02–1.10; p = 0.02; I² = 48%) or cohort studies (OR 1.09; 95% CI, 1.04–1.13; p < 0.0001; I² = 64%). Among studies adjusted for PSA screening, the association with localized PCa (OR 1.06; 95% CI, 1.03–1.09; p < 0.001; I² = 0%) remained significant. Conversely, vasectomy was no longer associated with localized high-grade (p = 0.19), advanced (p = 0.22), and lethal (p = 0.42) PCa.

Conclusions

Our meta-analysis found an association between vasectomy and any, mainly localized, PCa. However, the effect estimates of the association were increasingly close to null when examining studies of robust design and high quality. On exploratory analyses including studies, which adjusted for PSA screening, the association for aggressive and/or advanced PCa diminished.

Patient summary

In this study, we found an association between vasectomy and the risk of developing localized prostate cancer without being able to determine whether the procedure leads to a higher prostate cancer incidence.

Multiple pathogens and prostate cancer

BACKGROUND

The aim of this review is to consider whether multiple pathogens have roles in prostate cancer.

METHODS

We have reviewed case control studies in which infectious pathogens in prostate cancer were compared to normal and benign prostate tissues. We also reviewed additional evidence from relevant published articles.

RESULTS

We confirmed that high risk human papilloma viruses are a probable cause of prostate cancer. We judged Escherichia coli, Cutibacterium acnes, Neisseria gonorrhoea, Herpes simplex, Epstein Barr virus and Mycoplasmas as each having possible but unproven roles in chronic prostatic inflammation and prostate cancer. We judged Cytomegalovirus, Chlamydia trachomatis, Trichomonas vaginalis and the Polyoma viruses as possible but unlikely to have a role in prostate cancer.

CONCLUSIONS AND ACTIONS

The most influential cause of prostate cancer appears to be infection induced chronic inflammation. Given the high prevalence of prostate cancer it is important for action to can be taken without waiting for additional conclusive evidence. These include: 1. Encouragement of all boys (as well as girls) to have HPV vaccines 2. The vigorous use of antibiotics to treat all bacterial pathogens identified in the urogenital tract 3. The use of antiviral medications to control herpes infections 4. Education about safe sexual practices.

Association between vasectomy and risk of prostate cancer: a meta-analysis

BACKGROUND

The debate over the association between vasectomy and prostate cancer has been lasted about 40 years and there is no sign of stopping. In the present study, we aimed to evaluate whether vasectomy is associated with prostate cancer based on the most comprehensive and up-to-date evidence available.

METHODS

The PubMed, Cochrane Library, and EMBASE databases were systematically searched inception to March 14, 2021 without year or language restriction. Multivariable adjusted risk ratios (RRs) were used to assess each endpoint. Risk of bias was assessed using the Newcastle-Ottawa scale.

RESULTS

A total of 58 studies involving 16,989,237 participants fulfilled inclusion criteria. There was significant association of vasectomy with risk of any prostate cancer (risk ratio, 1.18, 95% CI, 1.07-1.31). Association between vasectomy and advanced prostate cancer (risk ratio, 1.06, 95% CI, 1.01-1.12), low-grade prostate cancer (risk ratio, 1.06, 95% CI, 1.02-1.10), and intermediate-grade prostate cancer (risk ratio, 1.12, 95% CI, 1.03-1.22) were significant. There was no significant association between vasectomy and prostate cancer-specific mortality (risk ratio, 1.01, 95% CI, 0.93-1.10).

CONCLUSIONS

This study found that vasectomy was associated with the risk of any prostate cancer and advanced prostate cancer. From the current evidence, patients should be fully informed of the risk of prostate cancer before vasectomy.

Lifestyle and Dietary Factors and Prostate Cancer Risk: A Multicentre Case-Control Study

This study aims to explore the association between fruit and vegetable intake, high fat, body mass index (BMI) score, physical activity, and the occurrence of prostate cancer among Jordanian men. A case-control study was conducted in three large referral hospitals. The sample included 165 prostate cancer patients in the case group and 177 healthy participants in the control group. The results showed that smoking (odds ratio [OR] = 0.32; 95% confidence interval [CI] = [0.18, 0.57]), a history of prostate infection (OR = 0.21; 95% CI = [0.11, 0.38]), high-fat intake (OR = 0.44; 95% CI = [0.23, 0.85]), and increased mean of BMI (OR = 1.08; 95% CI = [1.02, 1.13]) increased the likelihood of developing prostate cancer. Healthy diet and giving up smoking are recommended, as they may contribute to a reduction in the incidence of prostate cancer. More randomized clinical trials in this area are needed to strengthen the available evidence and reduce the effects of confounding variables.

The Association Between Vasectomy and Prostate Cancer: A Systematic Review and Meta-analysis

Importance

Despite 3 decades of study, there remains ongoing debate regarding whether vasectomy is associated with prostate cancer.

Objective

To determine if vasectomy is associated with prostate cancer.

Data Sources

The MEDLINE, EMBASE, Web of Science, and Scopus databases were searched for studies indexed from database inception to March 21, 2017, without language restriction.

Study Selection

Cohort, case-control, and cross-sectional studies reporting relative effect estimates for the association between vasectomy and prostate cancer were included.

Data Extraction and Synthesis

Two investigators performed study selection independently. Data were pooled separately by study design type using random-effects models. The Newcastle-Ottawa Scale was used to assess risk of bias.

Main Outcomes and Measures

The primary outcome was any diagnosis of prostate cancer. Secondary outcomes were high-grade, advanced, and fatal prostate cancer.

Results

Fifty-three studies (16 cohort studies including 2 563 519 participants, 33 case-control studies including 44 536 participants, and 4 cross-sectional studies including 12 098 221 participants) were included. Of these, 7 cohort studies (44%), 26 case-control studies (79%), and all 4 cross-sectional studies were deemed to have a moderate to high risk of bias. Among studies deemed to have a low risk of bias, a weak association was found among cohort studies (7 studies; adjusted rate ratio, 1.05; 95% CI, 1.02-1.09; P < .001; I2 = 9%) and a similar but nonsignificant association was found among case-control studies (6 studies; adjusted odds ratio, 1.06; 95% CI, 0.88-1.29; P = .54; I2 = 37%). Effect estimates were further from the null when studies with a moderate to high risk of bias were included. Associations between vasectomy and high-grade prostate cancer (6 studies; adjusted rate ratio, 1.03; 95% CI, 0.89-1.21; P = .67; I2 = 55%), advanced prostate cancer (6 studies; adjusted rate ratio, 1.08; 95% CI, 0.98-1.20; P = .11; I2 = 18%), and fatal prostate cancer (5 studies; adjusted rate ratio, 1.02; 95% CI, 0.92-1.14; P = .68; I2 = 26%) were not significant (all cohort studies). Based on these data, a 0.6% (95% CI, 0.3%-1.2%) absolute increase in lifetime risk of prostate cancer associated with vasectomy and a population-attributable fraction of 0.5% (95% CI, 0.2%-0.9%) were calculated.

Conclusions and Relevance

This review found no association between vasectomy and high-grade, advanced-stage, or fatal prostate cancer. There was a weak association between vasectomy and any prostate cancer that was closer to the null with increasingly robust study design. This association is unlikely to be causal and should not preclude the use of vasectomy as a long-term contraceptive option.

Lower Urinary Tract Infection and Subsequent Risk of Prostate Cancer: A Nationwide Population-Based Cohort Study

Purpose

We investigated whether lower urinary tract infection (LUTI), including cystitis or urethritis, is associated with an increased risk of developing prostate cancer (PCa), in a nationwide population-based cohort study.

Methods

We identified 14,273 men newly diagnosed with LUTI (9347 with cystitis, and 4926 with urethritis) between 1998 and 2011, from the Taiwan Longitudinal Health Insurance Database 2000. Each patient was randomly frequency-matched with 4 men without LUTI, based on age and index year of diagnosis. Cox’s proportional hazard regression analysis was performed to estimate the effect of LUTI on the PCa risk.

Results

The risk of developing PCa was significantly higher in the cystitis cohort (adjusted HR = 1.46, 95% CI = 1.20–1.78) and in the urethritis cohort (adjusted HR = 1.72, 95% CI = 1.26–2.34) than in the group without LUTI. Further analyses indicated that patients with more than 5 medical visits for LUTI per year had a significantly greater risk of developing PCa.

Conclusion

We found that cystitis or urethritis may play an etiological role in the development of PCa in Taiwanese men, particularly in those with repeated medical visits for cystitis or urethritis. Further studies are warranted on the association between LUTI and PCa in other countries, particularly where the prevalence of PCa is high.

Racial differences in the relationship between clinical prostatitis, presence of inflammation in benign prostate and subsequent risk of prostate cancer

BACKGROUND

Epidemiologic studies, primarily done in white men, suggest that a history of clinically-diagnosed prostatitis increases prostate cancer risk, but that histological prostate inflammation decreases risk. The relationship between a clinical history of prostatitis and histologic inflammation in terms of how these two manifestations of prostatic inflammation jointly contribute to prostate cancer risk and whether racial differences exist in this relationship is uncertain.

METHODS

Using a nested design within a cohort of men with benign prostate tissue specimens, we analyzed the data on both clinically-diagnosed prostatitis (NIH categories I-III) and histological inflammation in 574 prostate cancer case-control pairs (345 white, 229 African American).

RESULTS

Clinical prostatitis was not associated with increased prostate cancer risk in the full sample, but showed a suggestive inverse association with prostate cancer in African Americans (odds ratio (OR)=0.47; 95% confidence interval (CI)=0.27-0.81). In whites, clinical prostatitis increased risk by 40%, but was only associated with a significant increased prostate cancer risk in the absence of evidence of histological inflammation (OR=3.56; 95% CI=1.15-10.99). Moreover, PSA velocity (P=0.008) and frequency of PSA testing (P=0.003) were significant modifiers of risk. Clinical prostatitis increased risk of prostate cancer almost three-fold (OR=2.97; 95% CI=1.40-6.30) in white men with low PSA velocity and about twofold in white men with more frequent PSA testing (OR=1.91; 95% CI=1.09-3.35).

CONCLUSIONS

In our cohort of men with benign prostate specimens, race, and histological inflammation were important cofactors in the relationship between clinical prostatitis and prostate cancer. Clinical prostatitis was associated with a slightly decreased risk for prostate cancer in African American men. In white men, the relationship between clinical prostatitis and prostate cancer risk was modified by histological prostatic inflammation, PSA velocity, and frequency of PSA testing-suggesting a complex interplay between these indications of prostatic inflammation and prostate cancer detection.

An epidemiological analysis of potential associations between C-reactive protein, inflammation, and prostate cancer in the male US population using the 2009-2010 National Health and Nutrition Examination Survey (NHANES) data

Prostate cancer is the second leading cause of cancer-related deaths in US males, yet much remains to be learned about the role of inflammation in its etiology. We hypothesized that preexisting exposure to chronic inflammatory conditions caused by infectious agents or inflammatory diseases increase the risk of prostate cancer. Using the 2009-2010 National Health and Nutrition Examination Survey, we examined the relationships between demographic variables, inflammation, infection, circulating plasma C-reactive protein (CRP), and the risk of occurrence of prostate cancer in US men over 18 years of age. Using IBM SPSS, we performed bivariate and logistic regression analyses using high CRP values as the dependent variable and five study covariates including prostate cancer status. From 2009-2010, an estimated 5,448,373 men reported having prostate cancer of which the majority were Caucasian (70.1%) and were aged 40 years and older (62.7%). Bivariate analyses demonstrated that high CRP was not associated with an increased risk of prostate cancer. Greater odds of having prostate cancer were revealed for men that had inflammation related to disease (OR = 1.029, CI 1.029-1.029) and those who were not taking drugs to control inflammation (OR = 1.330, CI 1.324-1.336). Men who did not have inflammation resulting from non-infectious diseases had greater odds of not having prostate cancer (OR = 1.031, CI 1.030-1.031). Logistic regression analysis yielded that men with the highest CRP values had greater odds of having higher household incomes and lower odds of having received higher education, being aged 40 years or older, being of a race or ethnicity different from other, and of having prostate cancer. Our results show that chronic inflammation of multiple etiologies is a risk factor for prostate cancer and that CRP is not associated with this increased risk. Further research is needed to elucidate the complex interactions between inflammation and prostate cancer.

Genetic polymorphism of interleukin-1A (IL-1A), IL-1B, and IL-1 receptor antagonist (IL-1RN) and prostate cancer risk

PURPOSE

We aimed to investigate the associations between polymorphisms of interleukin-1A (IL-1A), IL-1B, and IL-1 receptor antagonist (IL-1RN) and prostate cancer (PCa) risk.

MATERIALS AND METHODS

A comprehensive search for articles of MEDLINE and EMBASE databases and bibliographies of retrieved articles published up to August 3, 2014 was performed. Methodological quality assessment of the trials was based on a standard quality scoring system. The meta-analysis was performed using STATA 12.0.

RESULTS

We included 9 studies (1 study for IL-1A, 5 studies for IL-1B, and 3 studies for IL-1RN), and significant association was found between polymorphisms of IL-1B-511 (rs16944) as well as IL-1B-31 (rs1143627) and PCa risk. IL-1B-511 (rs16944) polymorphism was significantly associated with PCa risk in homozygote and recessive models, as well as allele contrast (TT vs CC: OR, 0.74; 95%CI, 0.58-0.94; P=0.012; TT vs TC+CC; OR, 0.79; 95%CI, 0.63-0.98; P=0.033; T vs C: OR, 0.86; 95%CI, 0.77-0.96; P=0.008). The association between IL-1B-31 (rs1143627) polymorphism and PCa risk was weakly significant under a heterozygote model (OR, 1.35; 95%CI, 1.00-1.80; P=0.047).

CONCLUSIONS

Sequence variants in IL-1B-511 (rs16944) and IL-1B-31 (rs1143627) are significantly associated with PCa risk, which provides additional novel evidence that proinflammatory cytokines and inflammation play an important role in the etiology of PCa.

Gonorrhea and Prostate Cancer Incidence: An Updated Meta-Analysis of 21 Epidemiologic Studies

BACKGROUND

The association between gonorrhea and prostate cancer risk has been investigated widely, but the results remain inconsistent and contradictory. We conducted an updated meta-analysis to obtain a more precise estimate of this association.

MATERIAL AND METHODS

PubMed, EMBASE, and the Cochrane Library were searched for papers up to June 2014 to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the influence of gonorrhea on prostate cancer risk.

RESULTS

Twenty-one observational studies (19 case-control and 2 cohort) were eligible, comprising 9965 prostate cancer patients and 118 765 participants. Pooled results indicated that gonorrhea was significantly associated with increased incidence of prostate cancer (OR 1.31, 95% CI 1.14-1.52). The association between gonorrhea and prostate cancer was stronger in African American males (OR 1.32, 95% CI 1.06-1.65) than in Whites (OR 1.05, 95% CI 0.90-1.21).

CONCLUSIONS

Our findings suggest that gonorrhea is associated with an increased risk of prostate cancer, especially among African American males. These results warrant further well-designed, large-scale cohort studies to draw definitive conclusions.

Prostatitis, other genitourinary infections and prostate cancer: results from a population-based case-control study

PURPOSE

We relied on a population-based case-control study (PROtEuS) to examine a potential association between the presence of histologically confirmed prostate cancer (PCa) and history of genitourinary infections, e.g., prostatitis, urethritis, orchitis and epididymitis.

PATIENTS AND METHODS

Cases were 1933 men with incident PCa, diagnosed across Montreal hospitals between 2005 and 2009. Population controls were 1994 men from the same residential area and age distribution. In-person interviews collected information about socio-demographic characteristics, lifestyle and medical history, e.g., self-reported history of several genitourinary infections, as well as on PCa screening. Logistic regression analyses tested overall and grade-specific associations, including subgroup analyses with frequent PSA testing.

RESULTS

After multivariable adjustment, prostatitis was associated with an increased risk of any PCa (OR 1.81 [1.44-2.27]), but not urethritis (OR 1.05 [0.84-1.30]), orchitis (OR 1.28 [0.92-1.78]) or epididymitis (OR 0.98 [0.57-1.68]). The association between prostatitis and PCa was more pronounced for low-grade PCa (Gleason ≤ 6: OR 2.11 [1.61-2.77]; Gleason ≥ 7: OR 1.59 [1.22-2.07]). Adjusting for frequency of physician visits, PSA testing frequency or restricting analyses to frequently screened subjects did not affect these results.

CONCLUSION

Prostatitis was associated with an increased probability for detecting PCa even after adjustment for frequency of PSA testing and physician visits, but not urethritis, orchitis or epididymitis. These considerations may be helpful in clinical risk stratification of individuals in whom the risk of PCa is pertinent.

Sexual partners, sexually transmitted infections, and prostate cancer risk

BACKGROUND

The etiology of prostate cancer (PCa) is poorly understood. Sexual activity and sexually transmitted infections (STIs) are among factors under scrutiny, with controversial findings to date.

METHODS

We examined the association between the number and gender of sexual partners, STIs and PCa risk in the context of PROtEuS, a population-based case-control study set amongst the mainly French-speaking population in Montreal, Canada. The study included 1590 histologically-confirmed PCa cases diagnosed in a Montreal French hospital between 2005 and 2009, and 1618 population controls ascertained from the French electoral list, Montreal residents, frequency-matched to cases by age. In-person interviews elicited information on sociodemographic, lifestyle and environmental factors. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between sexually related factors and PCa risk, adjusting for age, ancestry, family history of PCa, and PCa screening history.

RESULTS

Subjects with more than 20 sexual partners in their lifetime had a decreased risk of PCa (OR 0.78, 95% CI 0.61-1.00) as did subjects who specifically had more than 20 female sexual partners (OR 0.72, 95% CI 0.56-0.94). By contrast, having had several male sexual partners appeared to confer some excess in risk of PCa. No association emerged for history of STIs and PCa but STIs prevalence was low.

CONCLUSION

Our findings are in support of a role for the number of sexual partners in PCa development. The gender of sexual partners should be taken into account in future studies investigating this association.

Sexually transmitted infections and prostate cancer risk: a systematic review and meta-analysis

Prostate cancer (PC) is the second most incident cancer and the sixth cause of death by cancer in men worldwide. Despite extensive research efforts, no modifiable risk factors have been consistently identified for PC risk. A number of studies have focused on possible relationships between sexually transmitted infections (STIs) and PC. We performed a meta-analysis to explore the association between infection caused by Neisseria gonorrheae, Treponema pallidum, Chlamydia trachomatis, Trichomonas vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, Herpes Simplex Virus types 1 and 2, Human Herpes Virus 8 and Cytomegalovirus, and PC. We conducted a comprehensive, systematic bibliographic search of medical literature to identify relevant studies. We calculated summary relative risk (SRR) and 95% confidence intervals (CI) for the association between each STI and PC through random effect models. Subgroup, meta-regression and sensitivity analyses were carried out to detect between-study heterogeneity and bias. We included 47 studies published between 1971 and 2011. Men who reported having ever had any STI in lifetime had an increased PC (SRR 1.49, 95% CI 1.19-1.92). We found a significantly increased PC risk in men having had gonorrhoea (SRR 1.20, 95% CI 1.05-1.37). No other single STI was significantly associated with PC. Due to high incidence of both STIs and PC worldwide, prevention of STIs may help preventing a considerable number of PC cases.

Epigallocatechin-3-gallate suppresses proinflammatory cytokines and chemokines induced by Toll-like receptor 9 agonists in prostate cancer cells

Chronic inflammation of the prostate contributes to the increased risk of prostate cancer. Microbial pathogens in the prostate cause inflammation that leads to prostatitis and proliferative inflammatory atrophy frequently associated with the development of prostate cancer. Bacterial lipopolysaccharides and DNA mediate immune responses by engaging Toll-like receptor (TLR) 4 and 9, respectively. Synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODN) mimic bacterial DNA and signal through TLR9 to initiate innate immune responses. Here, we show that stimulation of DU145, PC3, or LnCap prostate cancer cells by the TLR9 agonists, CpG-ODN, induces mRNA expression of IL-6, IL-8, CXCL1, IP-10, CCL5, and TGFβ. In addition, activity of matrix metalloproteinase (MMP)-9 and -2 and cell migration increased on CpG-ODN treatment. Induction of cytokines and chemokines was mediated by NF-κB activation and translocation to the nucleus. Treatment with epigallocatechin-3-gallate (EGCG), the major constituent of green tea, prior to CpG-ODN stimulation, inhibits cytokine and chemokine gene induction, activity of MMP-9 and -2, and cell migration. EGCG treatment sequesters the p65 subunit of transcription factor NF-κB in the cytoplasm and inhibits transcriptional activity of the NF-κB-driven promoter in response to CpG-ODN. Our results suggest that the ability of the TLR9 agonists, CpG-ODN, to induce cytokines, chemokines, and MMP activity, as well as suppression by EGCG are independent of the androgen receptor and p53 status of the cells. EGCG may provide protective effects against inflammation in the prostate and benefit prostate cancer treatment.

The role of prostatitis in prostate cancer: meta-analysis

Objective

Use systematic review methods to quantify the association between prostatitis and prostate cancer, under both fixed and random effects model.

Evidence Acquisition

Case control studies of prostate cancer with information on prostatitis history. All studies published between 1990-2012, were collected to calculate a pooled odds ratio. Selection criteria: the selection criteria are as follows: human case control studies; published from May 1990 to July 2012; containing number of prostatitis, and prostate cancer cases.

Evidence Synthesis

In total, 20 case control studies were included. A significant association between prostatitis and prostate cancer was found, under both fixed effect model (pooled OR=1.50, 95%CI: 1.39-1.62), and random effects model (OR=1.64, 95%CI: 1.36-1.98). Personal interview based case control studies showed a high level of association (fixed effect model: pooled OR=1.59, 95%CI: 1.47-1.73, random effects model: pooled OR= 1.87, 95%CI: 1.52-2.29), compared with clinical based studies (fixed effect model: pooled OR=1.05, 95%CI: 0.86-1.28, random effects model: pooled OR= 0.98, 95%CI: 0.67-1.45). Additionally, pooled ORs, were calculated for each decade. In a fixed effect model: 1990’s: OR=1.58, 95% CI: 1.35-1.84; 2000’s: OR=1.59, 95% CI: 1.40-1.79; 2010’s: OR=1.37, 95% CI: 1.22-1.56. In a random effects model: 1990’s: OR=1.98, 95% CI: 1.08-3.62; 2000’s: OR=1.64, 95% CI: 1.23-2.19; 2010’s: OR=1.34, 95% CI: 1.03-1.73. Finally a meta-analysis stratified by each country was conducted. In fixed effect models, U.S: pooled OR =1.45, 95%CI: 1.34-1.57; China: pooled OR =4.67, 95%CI: 3.08-7.07; Cuba: pooled OR =1.43, 95%CI: 1.00-2.04; Italy: pooled OR =0.61, 95%CI: 0.13-2.90. In random effects model, U.S: pooled OR=1.50, 95%CI: 1.25-1.80; China: pooled OR =4.67, 95%CI: 3.08-7.07; Cuba: pooled OR =1.43, 95%CI: 1.00-2.04; Italy: pooled OR =0.61, 95%CI: 0.13-2.90.CONCLUSIONS: the present meta-analysis provides the statistical evidence that the association between prostatitis and prostate cancer is significant.

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.

A review of African American-white differences in risk factors for cancer: prostate cancer

OBJECTIVE

African American men have higher prostate cancer incidence rates than White men, for reasons not completely understood. This review summarizes the existing literature of race-specific associations between risk factors and prostate cancer in order to examine whether associations differ.

METHODS

We reviewed epidemiologic studies published between January 1970 and December 2008 that reported race-specific effect estimates. We focused mainly on modifiable risk factors related to lifestyle and health. A total of 37 articles from 21 study populations met our inclusion criteria.

RESULTS

We found no evidence of racial differences in associations between prostate cancer and alcohol intake, tobacco use, and family history of prostate cancer. Research suggests that a modest positive association may exist between height and prostate cancer risk (all prostate cancer and advanced prostate cancer) among Whites only. No clear patterns were observed for associations with physical activity, weight/body mass index, dietary factors, occupational history, sexual behavior, sexually transmissible infections, and other health conditions.

DISCUSSION

Our results suggest few differences in prostate cancer risk factors exist between racial groups and underscore areas where additional research is needed. Future studies should enroll higher numbers of African American participants and report results for advanced prostate cancer.

Sexually transmitted infections and risk of prostate cancer: review of historical and emerging hypotheses

Since the early 1950s when sexually transmitted infections (STIs) were first proposed as a possible risk factor for prostate cancer, numerous epidemiologic studies have been conducted. Initially, these studies were primarily small case-control studies with retrospective, self-reported assessments of a narrow range of STIs, typically either any STIs, or gonorrhea and syphilis. However, as new STIs have been discovered/recognized, new and better tests to detect histories of STIs have been developed, and new resources for prostate cancer research have been created, epidemiologic studies have expanded to include a wide range of STIs, and have moved towards more rigorous, prospective study designs and serological assessment of STI histories. The results of these studies are reviewed and discussed, as well as possible new avenues of research, such as Trichomonas vaginalis infection and infections not typically considered to be sexually transmitted.

Prostatitis, sexually transmitted diseases, and prostate cancer: the California Men's Health Study

BACKGROUND

Prostatitis and sexually transmitted diseases (STDs) have been positively associated with prostate cancer in previous case-control studies. However, results from recent prospective studies have been inconclusive. METHODOGY/PRINCIPAL FINDINGS: We investigated the association between prostatitis, STDs, and prostate cancer among African American, Asian American, Latino, and White participants of the California Men's Health Study. Our analysis included 68,675 men, who completed a detailed baseline questionnaire in 2002-2003. We identified 1,658 incident prostate cancer cases during the follow-up period to June 30, 2006. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals. Overall, men having a history of prostatitis had an increased risk of prostate cancer than men with no history (RR = 1.30; 95% CI: 1.10-1.54). Longer duration of prostatitis symptoms was also associated with an increased risk of prostate cancer (P trend = 0.003). In addition, among men screened for prostate cancer (1 or 2 PSA tests), a non-significant positive association was observed between prostatitis and prostate cancer (RR = 1.10; 95% CI: 0.75-1.63). STDs were not associated with overall prostate cancer risk. In racial/ethnic stratified analysis, Latinos reporting any STDs had an increased risk of disease than those with no STDs (RR = 1.43; 95% CI: 1.07-1.91). Interestingly, foreign-born Latinos displayed a larger risk associated with STDs (RR = 1.87; 95% CI: 1.16-3.02) than U.S. born Latinos (RR = 1.15; 95% CI: 0.76-3.02).

CONCLUSION

In summary, results from this prospective study suggest that prostatitis and STDs may be involved in prostate cancer susceptibility. While we cannot rule out the possible influence of incidental detection, future studies are warranted to further investigate the role of infectious agents related to prostatitis and STDs in prostate cancer development.

Sexually transmitted infections and prostate cancer among men in the U.S. military

Studies of self-reported sexually transmitted infections (STI) suggesting an association with prostate cancer may reflect underreporting of such infections among nondiseased subjects. To reduce such bias, we studied archived sera in a cohort of U.S. military personnel known to have high rates of both STIs and prostate cancer. Using a nested case-control design, serum samples from 534 men who served on active duty between September 1, 1993 and September 1, 2003 were examined. Controls were individually matched to cases based on date of serum collection, date of birth, branch of service, military rank, marital status, and race. Each of the 267 case-control pairs had two serum samples: a recent serum sample, taken approximately 1 year before the case's prostate cancer diagnosis, and an earlier serum sample, taken approximately 8 years before diagnosis. Each serum specimen was studied for antibodies against human papillomavirus, herpes simplex virus-2 (HSV-2), and Chlamydia trachomatis. Logistic regression accounted for matching and potential confounding factors. Study data indicated no association between prostate cancer and serologic evidence of infections just before the reference date. However, a statistically significant association between prostate cancer and serologic evidence of HSV-2 infection was detected in the earlier sample (odds ratio, 1.60; 95% confidence interval, 1.05-2.44). The strength of this association increased when analyses were restricted to sera collected at least 60 months before diagnosis (odds ratio, 2.04; 95% confidence interval, 1.26-3.29; 204 pairs). If this association is causal, then our findings would suggest a long latency period for prostate cancer development after HSV-2 infection.

Prostate cancer and vasectomy: a hospital-based case-control study in China, Nepal and the Republic of Korea

BACKGROUND

The study of a possible relationship between vasectomy and prostate cancer has yielded mixed results. Data from developing countries are limited.

STUDY DESIGN

We conducted a hospital-based case-control study in China, Nepal and the Republic of Korea to evaluate the risk of prostate cancer after vasectomy.

RESULTS

Prostate cancer in 294 cases (confirmed by independent pathologists) and 879 matched controls were included. The odds ratio of prostate cancer in men with a history of vasectomy was 1.21 [95% confidence interval (95% CI)=0.79, 1.87]. No significant trend was observed in risk by time since vasectomy or age at vasectomy. The odds ratio for localized disease was 1.02 (95% CI=0.53, 1.95); the odds ratio for later stages was 1.41 (95% CI=0.78, 2.53). No confounding factor was identified. The study illustrated differential misclassification of disease by vasectomy status; reference pathologists determined that 28% of men with a history of vasectomy, compared with 17% of men without a history of vasectomy, were misdiagnosed with prostate cancer by local pathologists.

CONCLUSION

Vasectomy is not associated with an increased risk of prostate cancer in developing countries where the rate of the disease is low.

Direct visualization of Propionibacterium acnes in prostate tissue by multicolor fluorescent in situ hybridization assay

Prostate tissues from patients with prostate cancer and benign prostatic hyperplasia (BPH) frequently contain histological inflammation, and a proportion of these patients show evidence of Propionibacterium acnes infection in the prostate gland. We developed a multicolor fluorescent in situ hybridization (FISH) assay targeting P. acnes 23S rRNA along with a 14-kb region of the P. acnes genome. This assay was used to analyze prostate tissues from patients with prostate cancer and BPH. P. acnes infection of the prostate gland was demonstrated in prostatic tissue in 5 of 10 randomly selected prostate cancer patients. FISH analysis and confocal laser microscopy imaging revealed intracellular localization and stromal biofilm-like aggregates as common forms of P. acnes infection in prostate tissues from both prostate cancer and BPH patients. A sequential analysis of prostate tissue from individual patients suggested that P. acnes can persist for up to 6 years in the prostate gland. These results indicate that P. acnes can establish a persistent infection in the prostate gland. Further study is needed to clarify the link between this bacterium and prostatic inflammation which may contribute to the development of BPH and prostate cancer.

Inflammation in the etiology of prostate cancer: an epidemiologic perspective

The epidemiologic literature on sexually transmitted infections, clinical prostatitis, prostatic calculi, polymorphisms in immune response genes, and nonsteroidal antiinflammatory drug use as potential sources and modifiers of intraprostatic inflammation is reviewed in relation to prostate cancer. Particular emphasis is placed on study methodology and its influence on study findings. Although evidence from reviewed epidemiologic studies, together with laboratory and clinical studies, is suggestive of a role for prostatic inflammation in the etiology of prostate cancer, additional large, prospective studies are necessary to address methodological limitations of existing studies, and to investigate a broader range of potential sources of intraprostatic inflammation.

Increased expression of CCAAT/enhancer-binding protein beta in proliferative inflammatory atrophy of the prostate: relation with the expression of COX-2, the androgen receptor, and presence of focal chronic inflammation

BACKGROUND

Proliferative inflammatory atrophy (PIA) in the prostate has been proposed to be a precursor to prostate cancer. CCAAT/enhancer-binding protein beta (C/EBPbeta) is an important transcription factor involved in cellular proliferation and differentiation. Activation of C/EBPbeta plays a crucial role during the initial stage of cyclo-oxygenase 2 (COX-2) induction by proinflammatory mediators. Overexpression of C/EBPbeta has been reported in several human tumors. Nevertheless, the C/EBPbeta expression and functions in human prostate tissue are basically unknown.

METHODS

C/EBPbeta immunohistochemical staining was performed on 45 benign prostate hyperplasia (BPH) samples. The expression of C/EBPbeta in PIA lesions and normal-appearing acini was analyzed. In addition, by using double-IHC staining, C/EBPbeta expression and the association with chronic inflammatory cell density, co-expression of COX-2 and androgen receptor (AR) were also investigated.

RESULTS

C/EBPbeta was occasionally observed in normal-appearing prostate acini (4.9% +/- 6.7%, Mean +/- SD) but was clearly overexpressed in PIA lesions (81.8% +/- 16.4%) (P < 0.0001). Atrophic glands with T-lymphocyte and macrophage inflammation expressed higher level of C/EBPbeta. Furthermore, C/EBPbeta correlated significantly with COX-2 expression. Downregulation of the AR was common in PIA and was also related to the C/EBPbeta overexpression.

CONCLUSIONS

The data demonstrated that chronic inflammation appeared to play roles in the induction of C/EBPbeta expression in prostate epithelium, which was in turn associated with increased COX-2 expression and AR downregulation. In combining with other molecular alteration in the epithelium of PIA, it is suggested that these cells might be a kind of intermediate cells and involved in the pathogenesis of prostate cancer.

Gonorrhea, syphilis, clinical prostatitis, and the risk of prostate cancer

BACKGROUND

Although previous case-control studies have observed positive associations among gonorrhea, syphilis, clinical prostatitis, and prostate cancer, many may have been susceptible to recall and interviewer biases due to their retrospective designs. Therefore, to investigate these associations without concerns of recall and interviewer biases, we conducted a large, prospective investigation in the Health Professionals Follow-up Study.

METHODS

In 1992, participants were asked to report their histories of gonorrhea, syphilis, and clinical prostatitis by mailed questionnaire. Prostate cancer diagnoses were ascertained by self-report on the 1994 and each subsequent biennial follow-up questionnaire and confirmed by medical record review.

RESULTS

Of the 36,033 participants in this analysis, 2,263 were diagnosed with prostate cancer between the date of return of the 1992 questionnaire and 2002. No association was observed between gonorrhea [adjusted relative risk (RR), 1.04; 95% confidence interval (95% CI), 0.79-1.36] or syphilis (RR, 1.06; 95% CI, 0.44-2.59) and prostate cancer. Overall null results were also observed between clinical prostatitis and prostate cancer (RR, 1.08; 95% CI, 0.96-1.20), although a significant positive association was observed among younger men (<59 years) screened for prostate cancer (RR, 1.49; 95% CI, 1.08-2.06; P(interaction) = 0.006).

CONCLUSIONS

Gonorrhea and syphilis do not seem to be risk factors for prostate cancer in this cohort of men with a lower burden of sexually transmitted infections. Clinical prostatitis is also unlikely to be a risk factor, although possible roles for prostatitis in younger men and asymptomatic prostatic infection and inflammation cannot be ruled out.

Association between the presence of bacterial 16S RNA in prostate specimens taken during transurethral resection of prostate and subsequent risk of prostate cancer (Sweden)

OBJECTIVE

To study bacterial 16S RNA in archival prostate samples from 352 patients with benign prostate hyperplasia (BPH) and evaluate whether the presence of bacterial DNA was different in those who later developed prostate cancer (n = 171) and in the matched controls that did not progress to cancer (n = 181).

METHODS

16S DNA PCR followed by cloning and sequencing the positive samples.

RESULTS

In 96/352 (27%) of the prostate tissue specimens 16S RNA were detected. Sequence analysis revealed Propionibacterium acnes as the predominant microorganism (23% of 16S RNA positive patients). The second most frequent isolate-Escherichia coli was found in 12 (12%) patients. The other isolates included Pseudomonas sp. (3 patients), Actinomyces sp. (2), Streptococcus mutans (1), Corynebacterium sp. (2), Nocardioides sp. (1), Rhodococcus sp. (1) Veillonella sp. (2). In P. acnes positive samples 62% exhibited severe histological inflammation versus 50% in the bacteria-negative group (p = 0.602). The presence of P. acnes in the prostate was associated with prostate cancer development (OR 2.17, 95% CI 0.77-6.95).

CONCLUSIONS

This study has revealed P. acnes as the most common bacteria in the prostate in BPH. Further studies are needed to clarify its role in contributing to the development of prostatic inflammation and prostate cancer.

Sexual behavior, sexually transmitted diseases and prostatitis: the risk of prostate cancer in black men

PURPOSE

Black men are diagnosed with prostate cancer more often than white men, present with more advanced disease and have worse stage specific survival. Given the high risk of incidence and mortality in this population, determining potentially modifiable factors is important. Recent studies have suggested a link between chronic inflammation and development of prostate cancer. In concurrence, population based studies of white men have revealed an increased risk of prostate cancer with history of sexually transmitted diseases and prostatitis.

MATERIALS AND METHODS

We explored the chronic inflammation hypothesis of prostate cancer development among black men by examining sexual activity, sexually transmitted diseases and prostatitis in a population based study of 129 patients and 703 controls 40 to 79 years old.

RESULTS

After adjusting for age, income, cigarette smoking, and history of digital rectal examination and prostate specific antigen tests in the last 5 years, we observed that a history of gonorrhea infection and prostatitis increased the odds of prostate cancer 1.78-fold (95% CI 1.13, 2.79) and 4.93-fold (95% CI 2.79, 8.74), respectively. Men reporting 25 or more sexual partners were 2.80 (95% CI 1.29, 6.09) times more likely to be diagnosed with cancer compared to men with 5 or fewer partners.

CONCLUSIONS

Our findings support the significance of prior sexual practices, exposure to sexually transmitted microbial agents and history of prostatic infection in the natural history of prostate cancer in black men. Additional prospective research incorporating serological markers of infectious agents or predictive markers of chronic inflammation should serve to elucidate the possible causal pathway of recurring or persistent infection in the etiology of prostate cancer in black men.

Impact of a genetic variant in CYP3A4 on risk and clinical presentation of prostate cancer among white and African-American men

Genes involved in androgen metabolism are strong candidates for having an important role in the pathogenesis of prostate cancer. CYP3A4, a protein in the cytochrome P-450 supergene family, facilitates the oxidative deactivation of testosterone. In previous studies, patients with the G variant of a genetic polymorphism in CYP3A4 had prostate cancers with clinically aggressive characteristics at diagnosis. The association was strongest among elderly men. We investigated whether the CYP3A4 variant was linked with the diagnosis or clinical presentation of prostate cancer in a case control study of a multiethnic urban population. Biologic specimens were genotyped for CYP3A4, and analyzed for the impact of this genotype on risk and tumor characteristics at presentation, controlling for the effect of several cofactors. The CYP3A4 variant was more common among African-Americans than among white men. Race-stratified analyses revealed little association between the CYP3A4 variant and prostate cancer risk among white men but were limited by the small number of white men with the CYP3A4 variant. Of African-American men, while the variant G allele was not associated with prostate cancer that had less aggressive characteristics, it was associated with risk of aggressive prostate cancer when men with the AG genotype (odds ratio = 9.3, 95% confidence interval 1.3-411) or GG genotype (odds ratio = 11.9 95% confidence interval 1.6-533) were compared with those with the AA genotype. The association between the CYP3A4 genotype and aggressive prostate cancer in African-American men is consistent with findings of other studies.