High-risk prostate cancer: from definition to contemporary management

Context

High-risk prostate cancer (PCa) is a potentially lethal disease. It is clinically important to identify patients with high-risk PCa early on because they stand to benefit the most from curative therapy. Because of recent advances in PCa management, a multimodal approach may be advantageous.

Objective

Define high-risk PCa, and identify the best diagnostic and treatment patterns for patients with clinically localized and locally advanced disease. A critical analysis of published results following monomodal and/or multimodal therapy for high-risk PCa patients was also performed.

Evidence acquisition

A review of the literature was performed using the Medline, Embase, Scopus, and Web of Science databases as well as the Cochrane Database of Systematic Reviews.

Evidence synthesis

High-risk PCa accounts for ≤15% of all new diagnoses. Compared with patients with low- and intermediate-risk PCa, patients with high-risk PCa are at increased risk of treatment failure. Unfortunately, no contemporary randomized controlled trials comparing different treatment modalities exist. Evaluation of the results published to date shows that no single treatment can be universally recommended. Most often, a multimodal approach is warranted to optimize patient outcomes.

Conclusions

A significant minority of patients continue to present with high-risk PCa, which remains lethal in some cases. Outcomes following treatment of men with high-risk tumors have not substantially improved over time. However, not all high-risk patients are at the same risk of PCa progression and death. At present, a multimodal approach seems the best way to achieve acceptable outcomes for high-risk PCa patients.     

A New Era of Testosterone and Prostate Cancer: From Physiology to Clinical Implications

Context

Decades-old beliefs regarding androgens and prostate cancer (PCa) have undergone dramatic shifts in light of modern evidence and new theoretical constructs, but considerable confusion remains on this topic, particularly with regard to the use of testosterone therapy in men with any history of PCa.

Objective

To review current literature regarding the relationship of serum testosterone on PCa and in particular the effect of testosterone therapy on PCa progression and recurrence.

Evidence acquisition

A Medline search was conducted to identify all original and review articles assessing the effect of androgens on the prostate and the use of testosterone in men with a history of treated and untreated PCa.

Evidence synthesis

Contrary to traditional teaching, high endogenous serum testosterone does not increase the risk of developing PCa, and low serum testosterone does not protect against PCa. Although limited in size and duration, current studies similarly fail to indicate any increased risk of PCa in men receiving testosterone therapy. These results indicate a finite ability of androgens to stimulate PCa growth (the saturation model). A majority of studies demonstrate an association between low serum testosterone and poor prognostic features of PCa, including high-grade disease, advanced pathologic stage, and increased risk of biochemical recurrence following radical prostatectomy. The prostate-specific antigen-to-testosterone ratio predicted PCa risk in several biopsy studies. Multiple reports of testosterone therapy in men after treatment for localized PCa have shown low or absent recurrence rates. Some men with untreated PCa have received testosterone therapy without evidence for PCa progression.

Conclusions

The long-held belief that PCa risk is related to high serum androgen concentrations can no longer be supported. Current evidence indicates that maximal androgen-stimulated PCa growth is achieved at relatively low serum testosterone concentrations. It may therefore be reasonable to consider testosterone therapy in selected men with PCa and symptomatic hypogonadism.     

Castration-resistant Prostate Cancer: From New Pathophysiology to New Treatment Targets

Context

Castration-resistant prostate cancer (CRPC) refers to patients who no longer respond to surgical or medical castration. Standard treatment options are limited.

Objective

To review the concepts and rationale behind targeted agents currently in late-stage clinical testing for patients with CRPC.

Evidence acquisition

Novel targeted therapies in clinical trials were identified from registries. The MEDLINE database was searched for all relevant reports published from 1996 to October 2009. Bibliographies of the retrieved articles and major international meeting abstracts were hand-searched to identify additional studies.

Evidence synthesis

Advances in our understanding of the molecular mechanisms underlying prostate cancer (PCa) progression has translated into a variety of treatment approaches. Agents targeting androgen receptor (AR) activation and local steroidogenesis, angiogenesis, immunotherapy, apoptosis, chaperone proteins, the insulin-like growth factor (IGF) pathway, RANK-ligand, endothelin receptors, and the Src family kinases are entering or have recently completed accrual to phase 3 trials for patients with CRPC.

Conclusions

A number of new agents targeting mechanisms of PCa progression with early promising results are in clinical trials and have the potential to provide novel treatment options for CRPC in the near future.     

Adipocyte exosomes induce transforming growth factor beta pathway dysregulation in hepatocytes: a novel paradigm for obesity-related liver disease

Background

The pathogenesis of nonalcoholic fatty liver disease (NAFLD) has been attributed to increased systemic inflammation and insulin resistance mediated by visceral adipose tissue (VAT), although the exact mechanisms are undefined. Exosomes are membrane-derived vesicles containing messenger RNA, microRNA, and proteins, which have been implicated in cancer, neurodegenerative, and autoimmune diseases, which we postulated may be involved in obesity-related diseases. We isolated exosomes from VAT, characterized their content, and identified their potential targets. Targets included the transforming growth factor beta (TGF-β) pathway, which has been linked to NAFLD. We hypothesized that adipocyte exosomes would integrate into HepG2 and hepatic stellate cell lines and cause dysregulation of the TGF-β pathway.

Methods

Exosomes from VAT from obese and lean patients were isolated and fluorescently labeled, then applied to cultured hepatic cell lines. After incubation, culture slides were imaged to detect exosome uptake. In separate experiments, exosomes were applied to cultured cells and incubated 48-h. Gene expression of TGF-β pathway mediators was analyzed by polymerase chain reaction, and compared with cells, which were not exposed to exosomes.

Results

Fluorescent-labeled exosomes integrated into both cell types and deposited in a perinuclear distribution. Exosome exposure caused increased tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and integrin ανβ-5 expression and decreased matrix metalloproteinase-7 and plasminogen activator inhibitor-1 expression in to HepG2 cells and increased expression of TIMP-1, TIMP-4, Smad-3, integrins ανβ-5 and ανβ-8, and matrix metalloproteinase-9 in hepatic stellate cells.

Conclusions

Exosomes from VAT integrate into liver cells and induce dysregulation of TGF-β pathway members in vitro and offers an intriguing possibility for the pathogenesis of NAFLD.     

Is There Evidence of a Relationship between Benign Prostatic Hyperplasia and Prostate Cancer? Findings of a Literature Review

Context

More than half the male population aged >50 yr have histologic evidence of benign prostatic hyperplasia (BPH), while prostate cancer (PCa) is among the most common male cancers according to recent registry data. Understanding the aetiologies of both conditions is crucial to reduce the resulting burden of mortality and morbidity.

Objective

This review aims to examine the available data on the epidemiology, pathology, risk factors, and genetic markers involved in BPH and PCa; to discuss their clinical implications for management of both conditions; and to discuss their implications for PCa prevention. Our primary objective was to clarify the relationship between BPH and PCa by bringing together evidence from diverse areas of research.

Evidence acquisition

The primary source of data was PubMed, which was searched using Boolean strategies and by scanning lists of related articles. We also examined secondary sources from reference lists of retrieved articles and data presented at recent congresses.

Evidence synthesis

Accumulating evidence suggests that BPH and PCa share important anatomic, pathologic, and genetic links in addition to the well-established epidemiologic association between these conditions. We also found data that suggest interactions between apparently diverse factors, such as dihydrotestosterone levels and inflammation. Recent publications support the hypothesis that both BPH and PCa are part of the metabolic syndrome, while inflammation is emerging as a major contributor to the development of both BPH and PCa. Although many of the findings are preliminary and require further research, they offer new insight into the mechanisms of disease underlying the development of BPH and PCa.

Conclusions

Available data suggest that epidemiologic and pathologic links exist between BPH and PCa. Evidence of links between the conditions and contributory factors may offer common preventative strategies for BPH and PCa and common therapeutic approaches to their management.     

The Evolving Role of Oestrogens and Their Receptors in the Development and Progression of Prostate Cancer

Context

Oestrogens were proven effective in the hormonal treatment of advanced prostate cancer (PCa) >60 yr ago and are still used as second-line hormonal therapy. Paradoxically, oestrogens might also be involved in the development and progression of PCa.

Objective

To examine mechanisms of how oestrogens may affect prostate carcinogenesis and tumour progression.

Evidence acquisition

Recent data obtained from animal, experimental, and clinical studies were reviewed.

Evidence synthesis

The human prostate is equipped with a dual system of oestrogen receptors (oestrogen receptor alpha [ERα], oestrogen receptor beta [ERβ]) that undergoes profound remodelling during PCa development and tumour progression. In high-grade prostatic intraepithelial neoplasia (HGPIN), the ERα is upregulated and most likely mediates carcinogenic effects of estradiol as demonstrated in animal models. Preliminary clinical studies with the ERα antagonist toremifene have identified the ERα as a promising target for PCa prevention. The partial loss of the ERβ in HGPIN indicates that the ERβ acts as a tumour suppressor. The ERβ is generally retained in hormone-naïve PCa but is partially lost in castration-resistant disease. The progressive emergence of the ERα and the oestrogen-regulated progesterone receptor (PR) during PCa progression and hormone-refractory disease suggests that these tumours can use oestrogens and progestins for their growth. The TMPRSS2-ERG gene fusion recently reported as a potentially aggressive molecular subtype of PCa is regulated by ER-dependent signalling. TMPRSS2-ERG expression has been found to be increased by ERα agonist (oestrogens) and decreased by ERβ agonists.

Conclusions

Oestrogens and their receptors are implicated in PCa development and tumour progression. There is significant potential for the use of ERα antagonists and ERβ agonists to prevent PCa and delay disease progression. Tumours equipped with the pertinent receptors are potential candidates for this new therapeutic approach.     

A contemporary update on pathology reporting for prostate cancer: biopsy and radical prostatectomy specimens

Context

The diagnosis of and reporting parameters for prostate cancer (PCa) have evolved over time, yet they remain key components in predicting clinical outcomes.

Objective

Update pathology reporting standards for PCa.

Evidence acquisition

A thorough literature review was performed for articles discussing PCa handling, grading, staging, and reporting published as of September 15, 2011. Electronic articles published ahead of print were also considered. Proceedings of recent international conferences addressing these areas were extensively reviewed.

Evidence synthesis

Two main areas of reporting were examined: (1) prostatic needle biopsy, including handling, contemporary Gleason grading, extent of involvement, and high-risk lesions/precursors and (2) radical prostatectomy (RP), including sectioning, multifocality, Gleason grading, staging of organ-confined and extraprostatic disease, lymph node involvement, tumor volume, and lymphovascular invasion. For each category, consensus views, controversial areas, and clinical import were reviewed.

Conclusions

Modern prostate needle biopsy and RP reports are extremely detailed so as to maximize clinical utility. Accurate diagnosis of cancer-specific features requires up-to-date knowledge of grading, quantitation, and staging criteria. While some areas remain controversial, efforts to codify existing knowledge have had a significant impact on pathology practice.     

Metabolism of Kidney Cancer: From the Lab to Clinical Practice

Context

There is increasing evidence for the role of altered metabolism in the pathogenesis of renal cancer.

Objective

This review characterizes the metabolic effects of genes and signaling pathways commonly implicated in renal cancer.

Evidence acquisition

A systematic review of the literature was performed using PubMed. The search strategy included the following terms: renal cancer, metabolism, HIF, VHL.

Evidence synthesis

Significant progress has been made in the understanding of the metabolic derangements present in renal cancer. These findings have been derived through translational, in vitro, and in vivo studies. To date, the most well-characterized metabolic features of renal cancer are linked to von Hippel-Lindau (VHL) loss. VHL loss and the ensuing increase in the expression of hypoxia-inducible factor affect several metabolic pathways, including glycolysis and oxidative phosphorylation. Collectively, these changes promote a glycolytic metabolic phenotype in renal cancer. In addition, other histologic subtypes of renal cancer are also notable for metabolic derangements that are directly related to the causative genes.

Conclusions

Current knowledge of the genetics of renal cancer has led to significant understanding of the metabolism of this malignancy. Further studies of the metabolic basis of renal cell carcinoma should provide the foundation for the development of new treatment approaches and development of novel biomarkers.     

Obesity and Prostate Cancer: Weighing the Evidence

Context

Obesity and prostate cancer (PCa) affect substantial proportions of Western society. Mounting evidence, both epidemiologic and mechanistic, for an association between the two is of public health interest. An improved understanding of the role of this modifiable risk factor in PCa etiology is imperative to optimize screening, treatment, and prevention.

Objective

To consolidate and evaluate the evidence for an epidemiologic link between obesity and PCa, in addition to examining the proposed underlying molecular mechanisms.

Evidence acquisition

A PubMed search for relevant articles published between 1991 and July 2012 was performed by combining the following terms: obesity, BMI, body mass index and prostate cancer risk, prostate cancer incidence, prostate cancer mortality, radical prostatectomy, androgen-deprivation therapy, external-beam radiation, brachytherapy, prostate cancer and quality of life, prostate cancer and active surveillance, in addition to obesity, BMI, body mass index and prostate cancer and insulin, insulin-like growth factor, androgen, estradiol, leptin, adiponectin, and IL-6. Articles were selected based on content, date of publication, and relevancy, and their references were also searched for relevant articles.

Evidence synthesis

Increasing evidence suggests obesity is associated with elevated incidence of aggressive PCa, increased risk of biochemical failure following radical prostatectomy and external-beam radiotherapy, higher frequency of complications following androgen-deprivation therapy, and increased PCa-specific mortality, although perhaps a lower overall PCa incidence. These results may in part relate to difficulties in detecting and treating obese men. However, multiple molecular mechanisms could explain these associations as well. Weight loss slows PCa in animal models but has yet to be fully tested in human trials.

Conclusions

Obesity appears to be linked with aggressive PCa. We suggest clinical tips to better diagnose and treat obese men with PCa. Whether reversing obesity slows PCa growth is currently unknown, although it is an active area of research.     

Early Detection of Prostate Cancer: European Association of Urology Recommendation

Background

The recommendations and the updated EAU guidelines consider early detection of PCa with the purpose of reducing PCa-related mortality and the development of advanced or metastatic disease.

Objective

This paper presents the recommendations of the European Association of Urology (EAU) for early detection of prostate cancer (PCa) in men without evidence of PCa-related symptoms.

Evidence acquisition

The working panel conducted a systematic literature review and meta-analysis of prospective and retrospective clinical studies on baseline prostate-specific antigen (PSA) and early detection of PCa and on PCa screening published between 1990 and 2013 using Cochrane Reviews, Embase, and Medline search strategies.

Evidence synthesis

The level of evidence and grade of recommendation were analysed according to the principles of evidence-based medicine. The current strategy of the EAU recommends that (1) early detection of PCa reduces PCa-related mortality; (2) early detection of PCa reduces the risk of being diagnosed and developing advanced and metastatic PCa; (3) a baseline serum PSA level should be obtained at 40–45 yr of age; (4) intervals for early detection of PCa should be adapted to the baseline PSA serum concentration; (5) early detection should be offered to men with a life expectancy ≥10 yr; and (6) in the future, multivariable clinical risk-prediction tools need to be integrated into the decision-making process.

Conclusions

A baseline serum PSA should be offered to all men 40–45 yr of age to initiate a risk-adapted follow-up approach with the purpose of reducing PCa mortality and the incidence of advanced and metastatic PCa. In the future, the development and application of multivariable risk-prediction tools will be necessary to prevent over diagnosis and over treatment.     

Salvage cryoablation for locally recurrent prostate cancer following primary radiotherapy

Context

The purpose of this paper is to review current salvage cryoablation (SCA) outcomes in patients with locally recurrent prostate cancer (PCa) following primary radiation therapy.

Objective

The objectives of this review are (1) to analyze the eligibility criteria for careful patient selection for these salvage modalities and (2) to evaluate the oncologic results and reported complication rates for these respective modalities.

Evidence acquisition

A Medline/PubMed literature search was performed of peer-reviewed scientific articles published from 1991 to 2012 regarding salvage therapy for radiorecurrent PCa. The following search terms and various permutations were used: radiorecurrent prostate cancer, local salvage treatment, salvage radical prostatectomy, salvage cryoablation, salvage brachytherapy, and salvage high-intensity focused ultrasound. Only articles written in English were included.

Evidence synthesis

SCA is a feasible and efficacious treatment modality, especially using third-generation technology, whereby the biochemical disease-free survival is estimated to be between 50% and 70% at 5-yr follow-up in properly selected patients. Severe complications such as rectourethral fistulas are significantly less common over the last decade than was reported in the past. Because there are no prospective, randomized studies and the definitions of PSA failure vary among many studies, comparisons between these different salvage modalities are limited in terms of cancer-specific outcomes. Nevertheless, in recent years, tertiary care referral centers for prostate cryotherapy have reported their treatment outcomes using rigorous treatment end points and morbidity grading systems, dramatically improving the quality of reported clinical data. Consequently, favorable predictors of treatment outcomes have been identified.

Conclusions

The inability to effectively salvage patients with locally recurrent PCa following radiation therapy has in large part resulted from the lack of sufficiently sensitive and specific diagnostic tools to detect local recurrences at an early, potentially curable stage. Consequently, a more stringent definition of biochemical failure, improved imaging techniques, and accurate PCa mapping imaging technology is greatly needed within our diagnostic armamentarium. Additional research and randomized clinical trials are required to determine which salvage modality is superior in terms of oncologic efficacy and reduced morbidity.     

The Relationship Between Nutrition and Prostate Cancer: Is More Always Better?

Context

Prostate cancer (PCa) remains one of the most diagnosed malignancies in the world, correlating with regions where men consume more of a so-called Western-style diet. As such, there is much interest in understanding the role of lifestyle and diet on the incidence and progression of PCa.

Objective

To provide a summary of published literature with regard to dietary macro- and micronutrients and PCa incidence and progression.

Evidence acquisition

A literature search was completed using the PubMed database for all studies published on diet and PCa in June 2012 or earlier. Primary literature and meta-analyses were given preference over other review articles when possible.

Evidence synthesis

The literature was reviewed on seven dietary components: carbohydrates, protein, fat and cholesterol, vegetables, vitamins and minerals, and phytochemicals. Current literature linking these nutrients to PCa is limited at best, but trends in the published data suggest consumption of carbohydrates, saturated and ω-6 fats, and certain vitamin supplements may promote PCa risk and progression. Conversely, consumption of many plant phytochemicals and ω-3 fatty acids seem to slow the risk and progression of the disease. All other nutrients seem to have no effect or data are inconclusive. A brief summary about the clinical implications of dietary interventions with respect to PCa prevention, treatment, and survivorship is provided.

Conclusions

Due to the number and heterogeneity of published studies investigating diet and PCa, it is difficult to determine what nutrients make up the perfect diet for the primary and secondary prevention of PCa. Because diets are made of multiple macro- and micronutrients, further prospective studies are warranted, particularly those investigating the relationship between whole foods instead of a single nutritional component.     

Advances in magnetic resonance imaging: how they are changing the management of prostate cancer

Context

Although magnetic resonance imaging (MRI) is emerging as the most commonly used imaging modality for prostate cancer (PCa) detection, treatment planning, and follow-up, its acceptance has not been uniform. Recently, great interest has been shown in multiparametric MRI, which combines anatomic T2-weighted (T2W) imaging with MR spectroscopic imaging (MRSI), dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI).

Objective

The aim of this article is to review the current roles of these MR techniques in different aspects of PCa management: initial diagnosis, biopsy strategies, planning of radical prostatectomy (RP) and external radiation therapy (RT), and implementation of alternative focal therapies.

Evidence acquisition

The authors searched the Medline and Cochrane Library databases (primary fields: prostatic neoplasm, magnetic resonance). The search was performed without language restriction from January 2008 to November 2010.

Evidence synthesis

Initial diagnosis: The data suggest that the combination of T2W MRI and DWI or MRSI with DCE-MRI has the potential to guide biopsy to the most aggressive cancer foci in patients with previously negative biopsies, increasing the accuracy of the procedure. Transrectal MR-guided prostate biopsy can improve PCa detection, but its availability is still limited and the examination time is rather long. Planning of RP: It appears that adding MRSI, DWI, and/or DCE-MRI to T2W MRI can facilitate better preoperative characterization of cancer with regard to location, size, and relationship to prostatic and extraprostatic structures, and it may also facilitate early detection of local recurrence. Thus, use of these MR techniques may improve surgical, oncologic, and functional management. Planning of external RT and focal therapies: MR techniques have similar potential in these areas, but the published data remain very limited.

Conclusions

MRI technology is continuously evolving, and more extensive use of MRI technology in clinical trials and practice will help to improve PCa diagnosis and treatment planning.     

Prospective Multicentre Evaluation of PCA3 and TMPRSS2-ERG Gene Fusions as Diagnostic and Prognostic Urinary Biomarkers for Prostate Cancer

Background

Prostate cancer antigen 3 (PCA3) and v-ets erythroblastosis virus E26 oncogene homolog (TMPRSS2-ERG) gene fusions are promising prostate cancer (PCa) specific biomarkers that can be measured in urine.

Objective

To evaluate the diagnostic and prognostic value of Progensa PCA3 and TMPRSS2-ERG gene fusions (as individual biomarkers and as a panel) for PCa in a prospective multicentre setting.

Design, setting, and participants

At six centres, post–digital rectal examination first-catch urine specimens prior to prostate biopsies were prospectively collected from 497 men. We assessed the predictive value of Progensa PCA3 and TMPRSS2-ERG (quantitative nucleic acid amplification assay to detect TMPRSS2-ERG messenger RNA [mRNA]) for PCa, Gleason score, clinical tumour stage, and PCa significance (individually and as a marker panel). This was compared with serum prostate-specific antigen and the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculator. In a subgroup (n = 61) we evaluated biomarker association with prostatectomy outcome.

Outcome measurements and statistical analysis

Univariate and multivariate logistic regression analysis and receiver operating curves were used.

Results and limitations

Urine samples of 443 men contained sufficient mRNA for marker analysis. PCa was diagnosed in 196 of 443 men. Both PCA3 and TMPRSS2-ERG had significant additional predictive value to the ERSPC risk calculator parameters in multivariate analysis (p < 0.001 and resp. p = 0.002). The area under the curve (AUC) increased from 0.799 (ERSPC risk calculator), to 0.833 (ERSPC risk calculator plus PCA3), to 0.842 (ERSPC risk calculator plus PCA3 plus TMPRSS2-ERG) to predict PCa. Sensitivity of PCA3 increased from 68% to 76% when combined with TMPRSS2-ERG. TMPRSS2-ERG added significant predictive value to the ERSPC risk calculator to predict biopsy Gleason score (p < 0.001) and clinical tumour stage (p = 0.023), whereas PCA3 did not.

Conclusions

TMPRSS2-ERG had independent additional predictive value to PCA3 and the ERSPC risk calculator parameters for predicting PCa. TMPRSS2-ERG had prognostic value, whereas PCA3 did not. Implementing the novel urinary biomarker panel PCA3 and TMPRSS2-ERG into clinical practice would lead to a considerable reduction of the number of prostate biopsies.     

Risk-based prostate cancer screening

Context

Widespread mass screening of prostate cancer (PCa) is not recommended because the balance between benefits and harms is still not well established. The achieved mortality reduction comes with considerable harm such as unnecessary biopsies, overdiagnoses, and overtreatment. Therefore, patient stratification with regard to PCa risk and aggressiveness is necessary to identify those men who are at risk and may actually benefit from early detection.

Objective

This review critically examines the current evidence regarding risk-based PCa screening.

Evidence acquisition

A search of the literature was performed using the Medline database. Further studies were selected based on manual searches of reference lists and review articles.

Evidence synthesis

Prostate-specific antigen (PSA) has been shown to be the single most significant predictive factor for identifying men at increased risk of developing PCa. Especially in men with no additional risk factors, PSA alone provides an appropriate marker up to 30 yr into the future. After assessment of an early PSA test, the screening frequency may be determined based on individualized risk. A limited list of additional factors such as age, comorbidity, prostate volume, family history, ethnicity, and previous biopsy status have been identified to modify risk and are important for consideration in routine practice. In men with a known PSA, risk calculators may hold the promise of identifying those who are at increased risk of having PCa and are therefore candidates for biopsy.

Conclusions

PSA testing may serve as the foundation for a more risk-based assessment. However, the decision to undergo early PSA testing should be a shared one between the patient and his physician based on information balancing its advantages and disadvantages.