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.     

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.     

Potential Benefits of Intermittent Androgen Suppression Therapy in the Treatment of Prostate Cancer: A Systematic Review of the Literature

Context

The well-known side-effect profile of androgen-deprivation therapy (ADT) has significant quality-of-life (QoL) implications. Intermittent androgen deprivation (IAD) alternates androgen blockade with treatment cessation to allow hormonal recovery between treatment cycles, thus potentially improving tolerability and QoL.

Objective

To evaluate available evidence regarding the efficacy and tolerability of IAD and assess its value in the treatment of prostate cancer (PCa).

Evidence acquisition

Key phase 2/3 clinical trials of IAD in PCa published within the last 10 yr were identified on Medline using the terms prostatic neoplasms [MeSH], intermittent androgen suppression, intermittent hormonal deprivation, intermittent androgen deprivation, and intermittent hormonal therapy. Abstracts from trials reported at 2008–2009 conferences were also included.

Evidence synthesis

Data from 19 phase 2 studies are discussed with respect to prostate-specific antigen values for treatment suspension/reinitiation, treatment regimens, cycle lengths, testosterone normalisation, and tolerability. Outcome data were promising: Most trials reported an improvement in QoL during the off-therapy periods. Interim data from eight phase 3 trials comparing IAD and continuous androgen deprivation (CAD) support the phase 2 results. IAD generally showed comparable efficacy to CAD with respect to various outcomes, including biochemical progression, progression-free survival, and overall survival. However, IAD was significantly better than CAD with respect to 3-yr risk of progression in one study, and it demonstrated tolerability benefits, particularly with respect to sexual function. Patients most likely to benefit from IAD and factors predictive of poor response are also discussed.

Conclusions

IAD seems to be as effective as CAD while showing tolerability and QoL advantages, especially recovery of sexual potency; however, there are as yet insufficient data to determine whether IAD has the potential to prevent or reverse the long-term complications associated with ADT.     

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.     

Novel molecular targets for the therapy of castration-resistant prostate cancer

Context

Improved understanding of mechanisms underlying metastatic castration-resistant prostate cancer (mCRPC) progression has led to the recognition of multiple molecular targets and advances in the therapeutic landscape. The addition of abiraterone acetate, sipuleucel-T, cabazitaxel, and denosumab to the therapeutic armamentarium and the impending addition of MDV-3100 and radium-223 underscore the importance of androgen pathway inhibition, immunotherapy, tubulin antagonism, and pathophysiology of bone metastasis.

Objective

Review the next generation of molecular targets in mCRPC.

Evidence acquisition

Medline databases were searched for >100 original articles published as of October 18, 2011, with the search terms metastatic castration-resistant prostate cancer, targeted therapy, biologic agents, and immunotherapy. Proceedings from the last 5 yr of conferences of the American Society of Clinical Oncology, American Urological Association, European Society of Medical Oncology, and the European Association of Urology were also searched. We included novel and promising drugs that have reached clinical trial evaluation.

Evidence synthesis

The major findings were addressed in an evidence-based fashion. Prospective trials and important preclinical data were analyzed.

Conclusions

mCRPC is a disease with multiple molecular drivers. Molecular pathways being targeted in ongoing phase 3 trials are androgen signaling (MDV3100, TAK700), immunoregulatory pathways (ipilimumab, Prostvac-VF-TRICOM), Src (dasatinib), Met (cabozantinib), clusterin (custirsen), and angiogenesis (aflibercept, tasquinimod). The strides made in identifying multiple other novel molecular targets offer potential opportunities for further improving outcomes.     

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.     

Testosterone Measurement in Patients with Prostate Cancer

Context

Serum testosterone measurement has no widely accepted place in the management of patients with prostate cancer (PCa). However, several potential clinical applications of serum testosterone determination can be envisaged.

Objective

To review the role of testosterone and the androgen axis in the natural history of PCa and evaluate the evidence for the clinical application of serum testosterone measurement in patient screening, diagnosis, and management.

Evidence acquisition

A Medline search retrieved original research and review articles relating to the androgen axis in PCa and the use of testosterone measurement for (1) assessing PCa risk in the general population, (2) adding to the specificity of prostate-specific antigen (PSA) testing, (3) determining tumour aggressiveness, (4) assessing the efficacy of androgen-deprivation therapy (ADT), and (5) optimising the scheduling of intermittent ADT. Relevant data were reviewed during a roundtable discussion, and consensus recommendations were agreed.

Evidence synthesis

A body of data implicates the androgen axis in PCa throughout its natural history. Based on current evidence, serum testosterone measurement cannot be recommended for determining PCa risk, increasing specificity of PSA testing, or assessing tumour aggressiveness. In contrast, for patients receiving ADT, there is a clear rationale for serum testosterone monitoring to ensure that castration levels are achieved. Practical recommendations for testosterone measurement during ADT are outlined. If PSA is rising while on ADT, castration levels of serum testosterone must be demonstrated before hormonal independence can be assumed. Serum testosterone levels might be considered an additional trigger for therapy reinitiation in intermittent ADT schedules. Finally, future prospective studies should further evaluate the potential relevance of testosterone measurement as an independent assessment of prognosis and treatment decision in different disease stages.

Conclusions

As a therapeutic target, serum testosterone levels should be monitored to verify response to ADT and confirm suspected castration independence.     

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.     

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.     

Exosomes as biomarker treasure chests for prostate cancer

Context

Although progress has been made with regard to types of markers (protein, DNA, RNA, and metabolites) and implementation of improved technologies (mass spectrometry, arrays, and deep sequencing), the discovery of novel biomarkers for prostate cancer (PCa) in complex fluids, such as serum and urine, remains a challenge. Meanwhile, recent studies have reported that many cancer-derived proteins and RNAs are secreted through small vesicles known as exosomes.

Objective

This narrative review describes recent progress in exosome research, focusing on the potential role of exosomes as novel biomarkers for PCa. The purpose of this review is to acquaint clinicians and researchers in the field of urology with the potential role of exosomes as biomarker treasure chests and with their clinical value.

Evidence acquisition

Medline and Embase entries between 1966 and September 2010 were searched using the keywords exosomes, microvesicles, prostasomes, biomarkers, prostate cancer, and urology. Leading publications and articles constructively contributing to exosome research were selected for this review.

Evidence synthesis

Exosomes are small vesicles (50–100 nm) secreted by almost all tissues; they represent their tissue origin. Purification of prostate- and PCa-derived exosomes will allow us to profile exosomes, providing a promising source of protein and RNA biomarkers for PCa. This profiling will contribute to the discovery of novel markers for the early diagnosis and reliable prognosis of PCa.

Conclusions

Although the initial results are promising, further investigations are required to assess the clinical value of these exosomes in PCa.     

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.     

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.     

Novel Tools to Improve Patient Selection and Monitoring on Active Surveillance for Low-risk Prostate Cancer: A Systematic Review

Context

Active surveillance (AS) is an alternative to initial radical treatment of low-risk prostate cancer (PCa). Current criteria for selection and follow-up incorrectly exclude some patients eligible for AS and misclassify some who actually harbour significant disease. Better prediction of cancer behaviour at diagnosis would allow less strict monitoring and may improve acceptance of AS.

Objective

To review and critically analyse the literature on the value of novel clinical tools for patient selection and monitoring on AS.

Evidence acquisition

A comprehensive search of the PubMed database until July 10, 2013, was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis statement guidelines. Studies assessing novel markers and diagnostics for patient selection for AS and follow-up during AS were included. Studies analysing only classic clinical parameters used in current protocols (prostate-specific antigen, prostate volume, number of (positive) prostate biopsies, percentage malignant tissue, Gleason score) were excluded. This review focuses only on the AS setting and not on predicting insignificant disease in general.

Evidence synthesis

Of 787 studies on AS, 30 were included in this review: 14 on magnetic resonance imaging (MRI), 5 on serum markers, 5 on urinary markers, 4 on histopathology markers, and 2 on germline genetic markers. Several of these markers improve the prediction of tumour volume, tumour grade, or time to active treatment. MRI has a high specificity for low-risk PCa; new serum markers are associated with unfavourable disease. In none of the studies was the new marker used as the primary decision tool. Long-term outcome measures such as mortality were not assessed. The definition of indolent PCa is disputable.

Conclusions

Imaging and serum markers may improve future patient selection for AS and follow-up during AS. Prospective studies should aim to further evaluate the clinical utility of these new markers with respect to longer term outcomes of AS.

Patient summary

We searched the literature for articles reporting new ways to safely monitor low-risk prostate cancer for patients who have not had radical treatment. We found 30 articles. The most promising tools appear to be magnetic resonance imaging scans and various new blood markers. These may be used in the future within active surveillance regimens.     

Testosterone and Prostate Cancer: Revisiting Old Paradigms

Context

Androgens are vital for growth and maintenance of the prostate; however, the notion that pathologic prostate growth, benign or malignant, can be stimulated by androgens is a commonly held belief without scientific basis. Therefore, the current prostatic guidelines for testosterone therapy (TT) appear to be overly restrictive and should be reexamined.

Objective

To review the literature addressing the possible relationship between testosterone and prostate cancer (PCa) and to summarize the main aspects of this issue.

Evidence acquisition

A Medline search was conducted to identify original articles, review articles, and editorials addressing the relationship between testosterone and the risk of PCa development, as well as the impact of TT on PCa development and its natural history in men believed to be cured by surgery or radiation.

Evidence synthesis

Serum androgen levels, within a broad range, are not associated with PCa risk. Conversely, at time of PCa diagnosis, low rather than high serum testosterone levels have been found to be associated with advanced or high-grade disease. The available evidence indicates that TT neither increases the risk of PCa diagnosis nor affects the natural history of PCa in men who have undergone definitive treatment without residual disease. These findings can be explained with the saturation model (which states that prostatic homeostasis is maintained by a relatively low level of androgenic stimulation) and with the observation that exogenous testosterone administration does not significantly increase intraprostatic androgen levels in hypogonadal men. It must, however, be recognized that the literature remains limited regarding the effect of TT on PCa risk. Nonetheless, the current European Association of Urology guidelines state that in hypogonadal men who were successfully treated for PCa, TT can be considered after a prudent interval.

Conclusions

Although no controlled studies have yet been performed and there is a paucity of long-term data, the available literature strongly suggests that TT neither increases the risk of PCa diagnosis in normal men nor causes cancer recurrence in men who were successfully treated for PCa. Large prospective studies addressing the long-term effect of TT are needed to either refute or corroborate these hypotheses.     

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.     

Contemporary Role of Systematic Prostate Biopsies: Indications,Techniques, and Implications for Patient Care

Context

Prostate cancer (PCa) screening to detect early stage PCa has resulted in increased identification of small-volume, low-grade PCa, many of which meet criteria for clinically indolent disease. Nevertheless, there remains some degree of underdetection of high-risk PCa in substantial numbers of men despite current diagnostic strategies.

Objective

To discuss the contemporary role of prostate biopsy (PB), focusing on the indications, techniques, and limitations of current PB techniques and evolving techniques affecting patient care.

Evidence acquisition

A comprehensive Medline search was performed using the medical subject heading search terms prostate cancer, detection, prostate biopsy, significant cancer, and diagnosis, with restriction to the English language. Emphasis was given to publications within the past 5 yr.

Evidence synthesis

Because abnormal digital rectal examination (DRE) and prostate-specific antigen (PSA) tests alone lack specificity for cancer, there is no universal indication for PB. This lack has inspired exploration for a cancer-specific biomarker and prediction tools such as risk calculators. Indication for biopsy should involve a balance between the underdiagnosis of high-risk cancers and the potential risks for the overdetection of clinically insignificant cancers as well as biopsy-related morbidity. Evidence supports the inclusion of laterally directed cores during transrectal ultrasound (TRUS) PB in addition to the traditional sextant pattern, which significantly improves cancer detection without a demonstrable increase in morbidity. These data indicate that such PB templates, typically 12 cores, represent the optimal template in initial PB. Optimised techniques and templates for repeat PB remain controversial. However, debate continues regarding indications, sampling number, and location as well as on the potential of modern image-guided approaches or three-dimensional (3D) mapping biopsy in this unique setting. Additional limitations of repeat PB techniques include associated procedural risks if general anaesthesia is required and inherent sampling errors of template-based techniques that are not targeted to the specific tumour site.

Conclusions

Current data support the utility of extended PB templates for initial TRUS PB intended to detect clinically significant PCa. Repeat PB in the setting of prior negative PB on the grounds of clinical suspicion or for risk-stratified approaches to management of low risk PCa requires balancing overdetection of low-risk cancer with the potential to miss significant cancer. Several options, including modern image-guided targeting, biomarker development, transrectal saturation PB, and 3D template mapping PB, are changing the clinical paradigms for evaluation and management. Evidence to support adopting approaches other than the current established standards should be tested through appropriately designed prospective studies.