Detectable Prostate-Specific Antigen Nadir During Androgen-Deprivation Therapy Predicts Adverse Prostate Cancer–Specific Outcomes: Results from the SEARCH Database

Background

A prostate-specific antigen (PSA) level <0.2 ng/ml 8 mo after starting on androgen-deprivation therapy (ADT) is correlated with better outcomes. However, not all men reach a nadir PSA level within 8 mo. Whether the lowest PSA on ADT—specifically, <0.2 ng/ml—can be used for risk stratification is untested.

Objective

We examined the predictive value of small but detectable PSA nadir values on prostate cancer (PCa)–specific outcomes in men treated with early ADT after radical prostatectomy (RP).

Design, setting, and participants

We performed a retrospective review of men treated with ADT after RP before metastases from the SEARCH database. We identified 402 men treated with ADT for elevated PSA following RP, of whom 294 men had complete data. Median follow-up after PSA nadir was 49 mo. All men had a PSA nadir <4 ng/ml; 223 men (76%) had an undetectable nadir.

Intervention

ADT for an elevated PSA following RP with no radiographic evidence of metastatic disease.

Outcome measurements and statistical analysis

PSA nadir on ADT was defined as the lowest PSA value during ADT. Proportional hazards models and the C index were used to test the association and predictive accuracy, respectively, between PSA nadir and PCa-specific outcomes.

Results and limitations

Men with a PSA nadir between 0.01 and 0.2 ng/ml had a greater risk of progression to castration-resistant PCa (CRPC) (hazard ratio [HR]: 5.14; p < 0.001), metastases (HR: 3.98; p = 0.006), and PCa-specific mortality (PCSM) (HR: 5.33; p = 0.003) than men with an undetectable nadir. When data were restricted to men followed with ultrasensitive PSA values (sensitivity of 0.01 ng/ml), the C index of PSA nadir alone for predicting CRPC, metastases, and PCSM was 0.88, 0.91, and 0.96, respectively.

Conclusions

A PSA nadir on ADT, even at a very low level, strongly predicts progression to CRPC, metastases, and PCSM. Men with a detectable PSA nadir during ADT should be considered for clinical trials.     

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.     

Hedgehog signalling in androgen independent prostate cancer

Objectives

Androgen-deprivation therapy effectively shrinks hormone-naïve prostate cancer, both in the prostate and at sites of distant metastasis. However prolonged androgen deprivation generally results in relapse and androgen-independent tumour growth, which is inevitably fatal. The molecular events that enable prostate cancer cells to proliferate in reduced androgen conditions are poorly understood. Here we investigate the role of Hedgehog signalling in androgen-independent prostate cancer (AIPC).

Methods

Activity of the Hedgehog signalling pathway was analysed in cultured prostate cancer cells, and circulating prostate tumour cells were isolated from blood samples of patients with AIPC.

Results

AIPC cells were derived through prolonged culture in reduced androgen conditions, modelling hormone therapy in patients, and expressed increased levels of Hedgehog signalling proteins. Exposure of cultured AIPC cells to cyclopamine, which inhibits Hedgehog signalling, resulted in inhibition of cancer cell growth. The expression of the Hedgehog receptor PTCH and the highly prostate cancer–specific gene DD3^PCA3 was significantly higher in circulating prostate cancer cells isolated from patients with AIPC compared with samples prepared from normal individuals. There was an association between PTCH and DD3^PCA3 expression and the length of androgen-ablation therapy.

Conclusions

Our data are consistent with reports implicating overactivity of Hedgehog signalling in prostate cancer and suggest that Hedgehog signalling contributes to the androgen-independent growth of prostate cancer cells. As systemic anti-Hedgehog medicines are developed, the Hedgehog pathway will become a potential new therapeutic target in advanced prostate cancer.     

EAU guidelines on prostate cancer. Part II: Treatment of advanced, relapsing, and castration-resistant prostate cancer

Objectives

Our aim is to present a summary of the 2010 version of the European Association of Urology (EAU) guidelines on the treatment of advanced, relapsing, and castration-resistant prostate cancer (CRPC).

Methods

The working panel performed a literature review of the new data emerging from 2007 to 2010. The guidelines were updated, and the levels of evidence (LEs) and/or grades of recommendation (GR) were added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews.

Results

Luteinising hormone-releasing hormone (LHRH) agonists are the standard of care in metastatic prostate cancer (PCa). Although LHRH antagonists decrease testosterone without any testosterone surge, their clinical benefit remains to be determined. Complete androgen blockade has a small survival benefit of about 5%. Intermittent androgen deprivation (IAD) results in equivalent oncologic efficacy when compared with continuous androgen-deprivation therapy (ADT) in well-selected populations. In locally advanced and metastatic PCa, early ADT does not result in a significant survival advantage when compared with delayed ADT. Relapse after local therapy is defined by prostate-specific antigen (PSA) values >0.2 ng/ml following radical prostatectomy (RP) and >2 ng/ml above the nadir after radiation therapy (RT). Therapy for PSA relapse after RP includes salvage RT at PSA levels <0.5 ng/ml and salvage RP or cryosurgical ablation of the prostate in radiation failures. Endorectal magnetic resonance imaging and ¹¹C-choline positron emission tomography/computed tomography (CT) are of limited importance if the PSA is <2.5 ng/ml; bone scans and CT can be omitted unless PSA is >20 ng/ml. Follow-up after ADT should include screening for the metabolic syndrome and an analysis of PSA and testosterone levels. Treatment of castration-resistant prostate cancer (CRPC) includes second-line hormonal therapy, novel agents, and chemotherapy with docetaxel at 75 mg/m² every 3 wk. Cabazitaxel as a second-line therapy for relapse after docetaxel might become a future option. Zoledronic acid and denusomab can be used in men with CRPC and osseous metastases to prevent skeletal-related complications.

Conclusion

The knowledge in the field of advanced, metastatic, and CRPC is rapidly changing. These EAU guidelines on PCa summarise the most recent findings and put them into clinical practice. A full version is available at the EAU office or online at www.uroweb.org.     

Gonadotropin-releasing Hormone Agonists and Acute Kidney Injury in Patients with Prostate Cancer

Background

Androgen deprivation therapy (ADT) might increase the risk of acute kidney injury (AKI) in patients with prostate cancer (PCa).

Objective

To examine the impact of ADT on AKI in a large contemporary cohort of patients with nonmetastatic PCa representing the US population.

Design, setting, and participants

Overall, 69 292 patients diagnosed with nonmetastatic PCa between 1995 and 2009 were abstracted from the Surveillance Epidemiology and End Results–Medicare database.

Outcomes measurements and statistical analyses

Patient in both treatment arms (ADT vs no ADT) were matched using propensity-score methodology. Ten-year AKI rates were estimated. Competing-risks regression analyses tested the association between ADT and AKI, after adjusting for the risk of death during follow-up.

Results and limitations

Overall, the 10-yr AKI rates were 24.9% versus 30.7% for ADT-naive patients versus those treated with ADT, respectively (p < 0.001). When patients were stratified according to the type of ADT, the 10-yr AKI rates were 31.1% versus 26.0% for men treated with gonadotropin-releasing hormone (GnRH) agonists and bilateral orchiectomy, respectively (p < 0.001). In multivariable analyses, the administration of GnRH agonists (hazard ratio [HR]: 1.24; 95% confidence interval [CI], 1.18–1.31; p < 0.001), but not bilateral orchiectomy (HR: 1.11; 95% CI, 0.96–1.29; p = 0.1), was associated with the risk of experiencing AKI. Our study is limited by its retrospective design.

Conclusions

ADT is associated with an increased risk of AKI in patients with nonmetastatic PCa. In particular, the administration of GnRH agonists, but not surgical castration, may substantially increase the risk of experiencing AKI. These observations should help provide physicians with better patient selection to reduce the risk of AKI.

Patient summary

The administration of gonadotropin-releasing hormone agonists, but not bilateral orchiectomy, increases the risk of acute kidney injury (AKI) in patients with prostate cancer (PCa). These observations should help provide physicians with better patient selection to reduce the risk of AKI in PCa patients.     

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.     

Mutations in the AXIN1 gene in advanced prostate cancer

Background

The Wnt signalling pathway directs aspects of embryogenesis and is thought to contribute to maintenance of certain stem cell populations. Disruption of the pathway has been observed in many different tumour types. In bowel, stomach, and endometrial cancer, this is usually due to mutation of genes encoding Wnt pathway components APC or β-catenin. Such mutations are rare in hepatocellular carcinomas and medulloblastomas with Wnt pathway dysfunction, and there, mutation in genes for other Wnt molecules, such as Axin, is more frequently found.

Objective

Although evidence of abnormal activation of the Wnt pathway in prostate cancer has been demonstrated by several groups, APC and β-catenin mutations are infrequent. We sought mutations in genes encoding Wnt pathway participants in a panel of prostate cancer clinical specimens and cell lines.

Design, setting, and participants

DNA was obtained from 49 advanced prostate cancer specimens using laser microdissection followed by whole genome amplification and 8 prostate cancer cell lines.

Measurements

The DNA samples were screened for mutations in the genes encoding APC, β-catenin, and Axin. The subcellular distribution of β-catenin expression was assessed in the clinical specimens using immunohistochemistry.

Results and limitations

Abnormal patterns of β-catenin expression, suggesting Wnt pathway dysregulation, were observed in 71% of specimens. One APC mutation, two β-catenin gene mutations, and 7 DNA sequence variations in the Axin gene were detected. Four different Axin polymorphisms were also found in the cell lines. The study does not provide definite evidence that the observed sequence changes alter protein function, promoting neoplasia, but the potential functional relevance of these variants is discussed.

Conclusions

These data contribute to our understanding of the role of Wnt dysregulation in prostatic tumourigenesis and support the current interest in the pathway as a therapeutic target. Of particular interest, we identified three new potentially functionally relevant AXIN1 mutations.     

Human Prostate Fibroblasts Induce Growth and Confer Castration Resistance and Metastatic Potential in LNCaP Cells

Background

The tumor microenvironment is important for progressive and metastatic disease.

Objective

To study the hypothesis that prostate fibroblasts have differential ability to induce castration-resistant prostate cancer (PCa) and metastatic progression and whether this effect might vary depending on the zonal origin of the fibroblast.

Design, setting, and participants

Human prostate fibroblasts from the peripheral (PZ), transition (TZ) and central (CZ) zones of radical prostatectomy specimens (n = 13) were isolated and compared for their ability to promote androgen independence and metastatic progression in androgen-responsive PCa lymph node carcinoma of the prostate (LNCaP) cells in vivo.

Interventions

By coinoculating marginally tumorigenic LNCaP cells with PZ or TZ and by altering host hormonal milieu, a series of tumorigenic and metastatic LNCaP epithelial sublines–P4, P4-2 (derivatives from interaction with PZ), T4, and T4-2 (derivatives from interaction with TZ)–were established and characterized.

Measurements

In vivo and in vitro evaluation of induction of tumor growth and metastatic potential.

Results and limitations

1) LNCaP sublines were permanently altered in their cytogenetic and biologic profiles after cellular interaction with prostate stromal fibroblasts. LNCaP sublines grew faster under anchorage-dependent and -independent conditions, expressed 1–12-fold more prostate-specific antigen in vitro than LNCaP cells, and gained metastatic potential; 2) zonal differences of stromal fibroblasts in their ability to induce the growth and progression of LNCaP tumors as xenografts in mice may exist but need further analysis; 3) PZ-conditioned medium induced more anchorage-independent growth of LNCaP cells in vitro. TZ had a higher growth rate and were more sensitive to dihydrotestosterone.

Conclusions

We demonstrate that prostate fibroblasts have growth inductive potential on PCa cells and affect their subsequent progression to castration resistance and development of a metastatic phenotype.     

Androgen deprivation therapy for the treatment of prostate cancer: consider both benefits and risks

Context

Androgen deprivation therapy (ADT) is increasingly used for the treatment of prostate cancer (PCa), even in clinical settings in which there is no evidence-based proof of prolonged overall survival (OS). ADT, however, may be associated with numerous side effects, including an increased therapy-related cardiovascular mortality.

Objective

To discuss different clinical settings in which ADT is currently used and to critically weigh the benefits of ADT against its possible side effects.

Evidence acquisition

A MEDLINE search was conducted to identify original articles and review articles addressing the efficacy and side effects of ADT for the treatment of PCa. Keywords consisted of prostate cancer, hormonal therapy, adverse effects, radical prostatectomy, and radiotherapy. The articles with the highest level of evidence for the various examined end points were identified with the consensus of all authors and were reviewed.

Evidence synthesis

Even short-term use of ADT may lead to numerous side effects, such as osteoporosis, obesity, sarcopenia, lipid alterations, insulin resistance, and increased risk for diabetes and cardiovascular morbidity. Despite these side effects, ADT is commonly used in various clinical settings in which a clear effect on improved OS has not been shown.

Conclusions

ADT is associated with an increased risk of multiple side effects that may reduce quality of life and/or OS. Consequently, these issues should be discussed in detail with patients and their families before initiation of ADT. ADT should be used with knowledge of its potential long-term side effects and with possible lifestyle interventions, especially in settings with the highest risk–benefit ratio, to alleviate comorbidities.     

Androgen-deprivation therapy for nonmetastatic prostate cancer is associated with an increased risk of peripheral arterial disease and venous thromboembolism

Background

Previous studies demonstrate that androgen-deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists and orchiectomy for prostate cancer (PCa) is associated with cardiovascular disease. However, few studies have examined its effect on the peripheral vascular system.

Objective

To study the risk of peripheral artery disease (PAD) and venous thromboembolism associated with ADT for PCa.

Design, settings, and participants

This was a population-based observational study of 182 757 US men ≥66 yr of age who were diagnosed with nonmetastatic PCa from 1992 to 2007, with a median follow-up of 5.1 yr, of whom 47.8% received GnRH agonists and 2.2% orchiectomy.

Measurements

We used Cox proportional hazards models with time-varying treatment variables to adjust for demographic and tumor characteristics in assessing whether treatment with GnRH agonists or orchiectomy were associated with PAD and/or venous thromboembolism.

Results and limitations

GnRH agonist use was associated with an increased risk of incident PAD (adjusted hazard ratio [HR]: 1.16; 95% confidence interval [CI], 1.12–1.21) and incident venous thromboembolism (adjusted HR: 1.10; 95% CI, 1.04–1.15). In addition, orchiectomy was associated with an increased risk of peripheral arterial disease (adjusted HR: 1.13; 95% CI, 1.02–1.26) and venous thromboembolism (adjusted HR: 1.27; 95% CI, 1.11–1.45). Limitations include the observational study design and the inability to assess the use of oral antiandrogens.

Conclusions

ADT for nonmetastatic PCa is associated with an increased risk of PAD and venous thromboembolism. Additional research is needed to better understand the potential risks and benefits of ADT, so that this treatment can be targeted to patients for whom the benefits are clearest.     

Does Comorbidity Influence the Risk of Myocardial Infarction or Diabetes During Androgen-Deprivation Therapy for Prostate Cancer?

Background

Androgen-deprivation therapy (ADT) for prostate cancer (PCa) may be associated with cardiovascular disease and diabetes. Some data suggest that men with certain conditions may be more susceptible to developing cardiovascular disease than others.

Objective

To assess whether the risk of myocardial infarction (MI) or diabetes during ADT is modified by specific baseline comorbidities.

Design, setting, and participants

We conducted a population-based observational study of 185 106 US men ≥66 yr of age diagnosed with local/regional PCa from 1992 to 2007. We assessed comorbidities monthly over the follow-up period.

Outcome measurements and statistical analysis

Cox proportional hazards models with time-varying variables assessing incident diabetes or MI.

Results and limitations

A total of 49.9% of the men received ADT during follow-up. Among men with no comorbidities, ADT was associated with an increase in the adjusted hazard of MI (adjusted hazard ratio [AHR]: 1.09; 95% confidence interval [CI], 1.02–1.16) and diabetes (AHR: 1.33; 95% CI, 1.27–1.39). Risks of MI and diabetes were similarly increased among men with and without specific comorbid illnesses (p > 0.10 for all interactions, with one exception). Previous MI, congestive heart failure, peripheral arterial disease, stroke, hypertension, chronic obstructive pulmonary disease, and renal disease were associated with new MI and diabetes, and obesity and rheumatologic disease were also associated with diabetes. Limitations include the observational study design, reliance on administrative data to ascertain outcomes, and lack of information on risk factors such as smoking and family history.

Conclusions

Traditional risk factors for MI and diabetes were also associated with developing these conditions during ADT but did not significantly modify the risk attributable to ADT. Strategies to screen and prevent diabetes and cardiovascular disease in men with PCa should be similar to the strategies recommended for the general population.     

The Role of Radical Prostatectomy and Lymph Node Dissection in Lymph Node–Positive Prostate Cancer: A Systematic Review of the Literature

Context

Because pelvic lymph node (LN)-positive prostate cancer (PCa) is generally considered a regionally metastatic disease, surgery needs to be better defined.

Objective

To review the impact of radical prostatectomy (RP) and pelvic lymph node dissection (PLND), possibly in conjunction with a multimodal approach using local radiotherapy and/or androgen-deprivation therapy (ADT), in LN-positive PCa.

Evidence acquisition

A systematic Medline search for studies reporting on treatment regimens and outcomes in patients with LN-positive PCa undergoing RP between 1993 and 2012 was performed.

Evidence synthesis

RP can improve progression-free and overall survival in LN-positive PCa, although there is a lack of high-level evidence. Therefore, the former practice of aborting surgery in the presence of positive nodes might no longer be supported by current evidence, especially in those patients with a limited LN tumor burden. Current data demonstrate that the lymphatic spread takes an ascending pathway from the pelvis to the retroperitoneum, in which the internal and the common iliac nodes represent critical landmarks in the metastatic distribution. Sophisticated imaging technologies are still under investigation to improve the prediction of LN-positive PCa. Nonetheless, extended PLND including the common iliac arteries should be offered to intermediate- and high-risk patients to improve nodal staging with a possible benefit in prostate-specific antigen progression-free survival by removing significant metastatic load. Adjuvant ADT has the potential to improve overall survival after RP; the therapeutic role of a trimodal approach with adjuvant local radiotherapy awaits further elucidation. Age is a critical parameter for survival because cancer-specific mortality exceeds overall mortality in younger patients (<60 yr) with high-risk PCa and should be an impetus to treat as thoroughly as possible.

Conclusions

Increasing evidence suggests that RP and extended PLND improve survival in LN-positive PCa. Our understanding of surgery of the primary tumor in LN-positive PCa needs a conceptual change from a palliative option to the first step in a multimodal approach with a significant improvement of long-term survival and cure in selected patients.     

Does Local Treatment of the Prostate in Advanced and/or Lymph Node Metastatic Disease Improve Efficacy of Androgen-Deprivation Therapy? A Systematic Review

Context

Androgen-deprivation therapy (ADT) plays a pivotal role in the management of locally advanced and metastatic prostate cancer (PCa). When and for how long to apply ADT have remained controversial issues.

Objective

To review randomised studies of ADT (orchiectomy or luteinising hormone-releasing hormone analogues) in PCa—both immediate and deferred/adjuvant studies—to elucidate a possible interaction between local treatment and ADT.

Evidence acquisition

Published randomised studies on ADT in various stages of PCa were included in this review.

Evidence synthesis

Studies of immediate versus deferred ADT without local treatment consistently showed only limited benefit for overall survival (OS; hazard ratio [HR]: 0.90; 95% confidence interval [CI], 0.83–0.97) and cancer-specific survival (CSS; HR: 0.79; 95% CI, 0.71–0.89). In contrast, ADT as an adjuvant to radiation therapy in patients with high-risk localised disease or locally advanced disease was associated with substantial OS and CSS benefits. A similar benefit was seen in patients with proven systemic disease (node-positive patients after radical prostatectomy). Overall, the data suggest a clinically important survival benefit (HR for OS: 0.69; 95% CI, 0.61–0.79) when a local treatment has been applied to the primary tumour. Possible mechanisms of this therapeutic effect are discussed.

Conclusions

We conclude that an interaction between local treatment and ADT is suggested by this systematic review. In patients with advanced and aggressive disease who are at a high risk to die from PCa and who are treated for their primary tumour with curative intent, immediate and sustained ADT improves OS and CSS significantly. The local therapy in T3 and/or lymph node–positive disease is an essential part of the optimal treatment. However, this intensive treatment is unnecessary in a substantial number of patients with T3 and/or N1 disease with a slow natural history or high competing death risk.     

Metformin in Chemotherapy-naive Castration-resistant Prostate Cancer: A Multicenter Phase 2 Trial (SAKK 08/09)

Background

There is evidence linking metformin to improved prostate cancer (PCa)-related outcomes.

Objective

To evaluate treatment with metformin in patients with castration-resistant PCa (CRPC) and the effect of the treatment on progression-free survival (PFS) and PSA doubling time (PSA DT).

Design, setting, and participants

Forty-four men with progressive metastatic CRPC from 10 Swiss centers were included in this single-arm phase 2 trial between December 2010 and December 2011.

Intervention

Patients received metformin 1000 mg twice daily until disease progression.

Outcome measurements and statistical analysis

The primary end point was the absence of disease progression at 12 wk. Simon two-stage optimal design was applied. With a 5% significance level and 90% power, 44 patients were required to test PFS at 12 wk ≤15% (H₀) compared with ≥35% (H₁).

Results and limitations

Thirty-six percent of patients were progression-free at 12 wk, 9.1% were progression-free at 24 wk, and in two patients a confirmed ≥50% prostate-specific antigen (PSA) decline was demonstrated. In 23 patients (52.3%) we observed a prolongation of PSA DT after starting metformin. The homeostatic model assessment index fell by 26% from baseline to 12 wk, indicating an improvement in insulin sensitivity. There was a significant change in insulin-like growth factor-1 and insulin-like growth factor binding protein 3 from baseline to 12 wk. Sample size and lack of a control arm are the limitations of this trial; analyses are therefore exploratory.

Conclusions

Treatment with metformin is safe in nondiabetic patients, and it yields objective PSA responses and may induce disease stabilization. The activity of metformin in PCa, along with its low cost, favorable toxicity profile, and positive effect on metabolic parameters, suggests that further investigation of metformin as therapy for patients with PCa is of interest.

Patient summary

In this trial we assessed the use of the diabetes mellitus drug metformin in patients with advanced prostate cancer. We found disease stabilization and prolongation of prostate-specific antigen doubling time in some patients as well as effects on metabolic parameters.

Trial registration

This study is registered with ClinicalTrials.gov with the identifier NCT01243385.

Previous presentation

The study was presented at ESMO 2012 (abstract 1460).     

EAU Guidelines on Prostate Cancer. Part 1: Screening,Diagnosis, and Local Treatment with Curative Intent—Update 2013

Context

The most recent summary of the European Association of Urology (EAU) guidelines on prostate cancer (PCa) was published in 2011.

Objective

To present a summary of the 2013 version of the EAU guidelines on screening, diagnosis, and local treatment with curative intent of clinically organ-confined PCa.

Evidence acquisition

A literature review of the new data emerging from 2011 to 2013 has been performed by the EAU PCa guideline group. The guidelines have been updated, and levels of evidence and grades of recommendation have been added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews.

Evidence synthesis

A full version of the guidelines is available at the EAU office or online (www.uroweb.org). Current evidence is insufficient to warrant widespread population-based screening by prostate-specific antigen (PSA) for PCa. Systematic prostate biopsies under ultrasound guidance and local anesthesia are the preferred diagnostic method. Active surveillance represents a viable option in men with low-risk PCa and a long life expectancy. A biopsy progression indicates the need for active intervention, whereas the role of PSA doubling time is controversial. In men with locally advanced PCa for whom local therapy is not mandatory, watchful waiting (WW) is a treatment alternative to androgen-deprivation therapy (ADT), with equivalent oncologic efficacy. Active treatment is recommended mostly for patients with localized disease and a long life expectancy, with radical prostatectomy (RP) shown to be superior to WW in prospective randomized trials. Nerve-sparing RP is the approach of choice in organ-confined disease, while neoadjuvant ADT provides no improvement in outcome variables. Radiation therapy should be performed with ≥74 Gy in low-risk PCa and 78 Gy in intermediate- or high-risk PCa. For locally advanced disease, adjuvant ADT for 3 yr results in superior rates for disease-specific and overall survival and is the treatment of choice. Follow-up after local therapy is largely based on PSA and a disease-specific history, with imaging indicated only when symptoms occur.

Conclusions

Knowledge in the field of PCa is rapidly changing. These EAU guidelines on PCa summarize the most recent findings and put them into clinical practice.

Patient summary

A summary is presented of the 2013 EAU guidelines on screening, diagnosis, and local treatment with curative intent of clinically organ-confined prostate cancer (PCa). Screening continues to be done on an individual basis, in consultation with a physician. Diagnosis is by prostate biopsy. Active surveillance is an option in low-risk PCa and watchful waiting is an alternative to androgen-deprivation therapy in locally advanced PCa not requiring immediate local treatment. Radical prostatectomy is the only surgical option. Radiation therapy can be external or delivered by way of prostate implants. Treatment follow-up is based on the PSA level.     

Prospective Study of Diagnostic Accuracy Comparing Prostate Cancer Detection by Transrectal Ultrasound–Guided Biopsy Versus Magnetic Resonance (MR) Imaging with Subsequent MR-guided Biopsy in Men Without Previous Prostate Biopsies

Background

The current diagnosis of prostate cancer (PCa) uses transrectal ultrasound–guided biopsy (TRUSGB). TRUSGB leads to sampling errors causing delayed diagnosis, overdetection of indolent PCa, and misclassification. Advances in multiparametric magnetic resonance imaging (mpMRI) suggest that imaging and selective magnetic resonance (MR)–guided biopsy (MRGB) may be superior to TRUSGB.

Objective

To compare the diagnostic efficacy of the magnetic resonance imaging (MRI) pathway with TRUSGB.

Design, setting, and participants

A total of 223 consecutive biopsy-naive men referred to a urologist with elevated prostate-specific antigen participated in a single-institution, prospective, investigator-blinded, diagnostic study from July 2012 through January 2013.

Intervention

All participants had mpMRI and TRUSGB. Men with equivocal or suspicious lesions on mpMRI also underwent MRGB.

Outcome measurements and statistical analysis

The primary outcome was PCa detection. Secondary outcomes were histopathologic details of biopsy and radical prostatectomy specimens, adverse events, and MRI reader performance. Sensitivity, specificity, negative predictive values (NPVs), and positive predictive values were estimated and basic statistics presented by number (percentage) or median (interquartile range).

Results and limitations

Of 223 men, 142 (63.7%) had PCa. TRUSGB detected 126 cases of PCa in 223 men (56.5%) including 47 (37.3%) classed as low risk. MRGB detected 99 cases of PCa in 142 men (69.7%) with equivocal or suspicious mpMRI, of which 6 (6.1%) were low risk. The MRGB pathway reduced the need for biopsy by 51%, decreased the diagnosis of low-risk PCa by 89.4%, and increased the detection of intermediate/high-risk PCa by 17.7%. The estimated NPVs of TRUSGB and MRGB for intermediate/high-risk disease were 71.9% and 96.9%, respectively. The main limitation is the lack of long follow-up.

Conclusions

We found that mpMRI/MRGB reduces the detection of low-risk PCa and reduces the number of men requiring biopsy while improving the overall rate of detection of intermediate/high-risk PCa.

Patient summary

We compared the results of standard prostate biopsies with a magnetic resonance (MR) image–based targeted biopsy diagnostic pathway in men with elevated prostate-specific antigen. Our results suggest patient benefits of the MR pathway. Follow-up of negative investigations is required.     

Whole-gland Ablation of Localized Prostate Cancer with High-intensity Focused Ultrasound: Oncologic Outcomes and Morbidity in 1002 Patients

Background

High-intensity focused ultrasound (HIFU) is a nonsurgical therapy for selected patients with localized prostate cancer (PCa).

Objective

The long-term oncologic and morbidity outcomes of primary HIFU therapy for localized PCa were evaluated in a prospective, single-arm, single-institution cohort study.

Design, setting, and participants

Participants were patients treated with HIFU for localized PCa from 1997 to 2009. Excluded were patients with local recurrence following radiotherapy. A second HIFU session was systematically performed in patients with biopsy-proven local recurrence.

Intervention

Whole-gland prostate ablation with transrectal HIFU.

Outcome measurements and statistical analysis

Incontinence was assessed using the Ingelman-Sundberg score, and potency was assessed using the five-item version of the International Index of Erectile Function (IIEF-5) scores. Primary outcomes were survival rates (biochemical-free, cancer-specific, metastasis-free, and overall survival). Secondary outcomes were morbidity rates. Median follow-up was 6.4 yr (range: 0.2–13.9). The Kaplan-Meier method was used to determine survival estimates, and multivariate analysis was used to determine predictive factors of biochemical progression.

Results and limitations

A total of 1002 patients were included. The median nadir prostate-specific antigen (PSA) was 0.14 ng/ml, with 63% of patients reaching a nadir PSA ≤0.3 ng/ml. Sixty percent of patients received one HIFU session, 38% received two sessions, and 2% received three sessions. The 8-yr biochemical-free survival rates (Phoenix definition) were 76%, 63%, and 57% for low-, intermediate-, and high-risk patients, respectively (p < 0.001). At 10 yr, the PCa-specific survival rate and metastasis-free survival rate (MFSR) were 97% and 94%, respectively. Salvage therapies included external-beam radiation therapy (EBRT) (13.8%), EBRT plus androgen-deprivation therapy (ADT) (9.7%), and ADT alone (12.1%). Severe incontinence and bladder outlet obstruction decreased with refinement in the technology, from 6.4% and 34.9% to 3.1% and 5.9%, respectively. Limitations included the fact that the study was a single-arm study without a comparison group, technological improvements, changes in surgical protocol during the study, and the use of ADT to downsize the prostate in 39% of patients.

Conclusions

HIFU is a potentially effective treatment of localized PCa, with a low PCa-specific mortality rate and a high MFSR at 10 yr as well as acceptable morbidity.