Expression of the Androgen-Regulated Fusion Gene TMPRSS2-ERG Does Not Predict Response to Endocrine Treatment in Hormone-Naïve,Node-Positive Prostate Cancer

Background

Fusion of the androgen-regulated gene transmembrane protease, serine 2, TMPRSS2, to the v-ets erythroblastosis virus E26 oncogene homolog (avian), ERG, of the erythroblast transformation-specific (ETS) family is the most common genetic alteration in prostate cancer (PCa).

Objective

To determine whether expression of androgen-regulated TMPRSS2-ERG predicts response to endocrine treatment in hormone-naïve, node-positive PCa.

Design, setting, and participants

Eighty-five patients with histologically confirmed, node-positive PCa who were without treatment at the moment of lymph node dissection were analysed. RNA was isolated from the paraffin-embedded lymph node metastases and complementary DNA (cDNA) was made. The quality of cDNA was tested by polymerase chain reaction (PCR) analysis of the expression of the housekeeping gene hydroxymethylbilane synthase, HMBS (formerly PBGD). TMPRSS2-ERG expression was analysed by PCR using a forward primer in TMPRSS2 exon 1 and a reverse primer in ERG exon 4.

Measurements

The primary end point was time from start of endocrine therapy to the occurrence of three consecutive rises in prostate-specific antigen (PSA) that were at least 2 wk apart and resulted in two 50% increases over the PSA nadir. Secondary end points were time to PSA nadir after start of endocrine treatment and cancer-specific and overall survival.

Results and limitations

TMPRSS2-ERG was expressed in 59% of the 71 patients who could be analysed. Median duration of response to endocrine therapy was 20.9 mo versus 24.1 mo for gene fusion–positive versus gene fusion–negative patients (95% confidence intervals: 18.6–23.1 vs 18.9–29.4, p = 0.70). Furthermore, no significant differences were seen between the two groups for the secondary end points.

Conclusions

Expression of TMPRSS2-ERG is frequent in lymph node metastases of patients with untreated PCa; however, expression of this androgen-regulated fusion gene did not correspond with duration of response to endocrine therapy. Our results suggest that expression of TMPRSS2-ERG is not a candidate marker to select for metastatic PCa patients who will benefit more from endocrine treatment.     

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.     

Overexpression of ELAV-like protein HuR is associated with increased COX-2 expression in atrophy, high-grade prostatic intraepithelial neoplasia, and incidental prostate cancer in cystoprostatectomies

Background

The human ELAV-like protein HuR regulates the stability of several mRNA targets, including that of cyclooygenase-2 (COX-2). Their expression in prostatic carcinogenesis is uncertain.

Objective

To analyze HuR and COX-2 expression in cystoprostatectomies (CyPs) with incidental prostate cancer and compare their expression with those in radical prostatectomies (RPs) with clinically detected cancer.

Design, setting, and participants

HuR and COX-2 were immunohistochemically evaluated in normal-looking epithelium (NEp), atrophy, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostate carcinoma (PCa) in 20 CyPs and 20 RPs, both types of specimens with pT2a Gleason score 6 PCa.

Measurements

At least 1000 cells were counted in contiguous 400X microscopic fields in each case, separately for NEp, atrophy, HGPIN, and PCa.

Results and limitations

There was an increase in the percentage of secretory cells with cytoplasmic HuR staining from NEp to atrophy, HGPIN, and PCa. The mean percentages in NEp, atrophy, and HGPIN adjacent to PCa were greater than away from cancer, both in the CyP and RPs. There was a trend towards a reduced nuclear HuR expression in atrophy, HGPIN, and PCa, compared to NEp. COX-2 staining was seen in the cytoplasm of the basal and secretory cells. There was a reduction in the mean proportion of positive basal cells and progressive increase in the percentage of positive secretory cells from atrophy to HGPIN and PCa, compared to NEp. Cytoplasmic HuR overexpression was correlated with COX-2 expression. There was no difference in HuR and COX-2 expression between cancers with tumour volume <0.5 ccm or >0.5 ccm.The limitations of this study were the small number of cases investigated and lack of a control group without cancer.

Conclusions

The secretory cells showed shift in HuR staining from nuclear in NEp to cytoplasmic in PCa. This is associated with a parallel shift in COX-2 expression from basal to secretory cells.     

A panel of TMPRSS2:ERG fusion transcript markers for urine-based prostate cancer detection with high specificity and sensitivity

Background

The TMPRSS2:ERG fusion is both prevalent and unique to prostate cancer (PCa) and has great potential for noninvasive diagnosis of PCa in bodily fluids.

Objectives

To evaluate the specificity and sensitivity of the TMPRSS2:ERG fusion in urine from diverse clinical contexts and to explore potential clinical applications.

Design, setting, and participants

A total of 101 subjects were enrolled in 2008 from urologic oncology clinics to form three study groups: 44 PCa free, 46 confirmed PCa, and 11 negative prostate biopsies. The PCa-free group included females, healthy young men, and post–radical prostatectomy (RP) patients. The confirmed PCa group was composed of patients under active surveillance, scheduled for treatment, or with metastatic disease.

Measurements

Urine was collected after attentive digital rectal exam (DRE) and coded to blind group allocation for laboratory test. RNA from urine sediments was analyzed using a panel of four TMPRSS2:ERG fusion markers with quantitative polymerase chain reaction (qPCR).

Results and limitations

Our fusion markers demonstrated very high technical specificity and sensitivity for detecting a single fusion-positive cancer cell (VCaP) in the presence of at least 3000 cells in urine sediments. In clinical analysis, there were no fusion-positive samples in the PCa-free group (0 of 44 samples), while there were 16 of 46 (34.8%) fusion-positive samples in the confirmed PCa group. The fusion incidence varied significantly among the three PCa subgroups. The clinical sensitivity increased to 45.4% in cancer patients prior to treatments. The fusion markers were detected in 2 of 11 (18.2%) biopsy-negative patients, suggesting potentially false negative biopsies. This study is not prospective and is limited in sample sizes.

Conclusions

Our novel panel of TMPRSS2:ERG fusion markers provided a very specific and sensitive tool for urine-based detection of PCa. Theses markers can potentially be used to diagnose patients with PCa who have negative biopsies.     

A 36-gene Signature Predicts Clinical Progression in a Subgroup of ERG-positive Prostate Cancers

Background

The molecular basis of the clinical heterogeneity of prostate cancer (PCa) is not well understood.

Objective

The purpose of our study was to identify and characterize genes in a clinically relevant gene expression signature in a subgroup of primary PCa positive for transmembrane protease, serine 2 (TMPRSS2)–v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG).

Design, setting, and participants

We studied gene expression profiles by unsupervised hierarchical clustering in 48 primary PCas from patients with a long clinical follow-up. Results were correlated with clinical outcome and validated in an independent patient cohort. Selected genes from a defined classifier were tested in vitro for biologic properties.

Intervention

Initial treatment of primary tumors was radical prostatectomy.

Outcome measurements and statistical analysis

Associations between clinical and histopathologic variables were evaluated by the Pearson χ² test, Mann-Whitney U test, or Kruskal-Wallis test, where appropriate. The log-rank test or Breslow method was used for statistical analysis of Kaplan-Meier survival curves.

Results and limitations

Most tumors that overexpressed ERG clustered separately from other primary PCas. No differences in any clinical end points between ERG-positive and ERG-negative cancers were detected. Importantly, within the ERG-positive samples, two subgroups were identified, which differed significantly in prostate-specific antigen recurrence-free survival, and cancer-specific and overall survival. From our findings, we defined a gene expression classifier of 36 genes. In a second, completely independent tumor set, the classifier also distinguished ERG-positive subgroups with different clinical outcome. In both patient cohorts, the classifier was not predictive in ERG-negative tumors. Biologic processes regulated by genes in the classifier included cell adhesion and bone remodeling. Tumor growth factor-β signaling was indicated as the main differing signaling pathway between the two ERG subgroups. In vitro biologic assays of two selected genes from the classifier (inhibin, beta A [INHBA] and cadherin 11, type 2, OB-cadherin (osteoblast) [CDH11]) supported a functional role in PCa progression. Possible multifocality and limited number of PCa samples can be limitations of the study.

Conclusions

The classifier identified can contribute to prediction of tumor progression in ERG-positive primary prostate tumors and might be instrumental in therapy decisions.     

Sarcosine in Urine after Digital Rectal Examination Fails as a Marker in Prostate Cancer Detection and Identification of Aggressive Tumours

Background

Sarcosine in urine was recently suggested to be a promising tool in prostate cancer (PCa) diagnostics.

Objective

To reevaluate sarcosine as a potential biomarker for early PCa detection and for prediction of tumour aggressiveness.

Design, setting, and participants

Sarcosine was measured in urine samples from 106 PCa patients and 33 patients with no evidence of malignancy (NEM), confirmed by 8–12 core prostate biopsies, after standardised digital rectal examination, as well as from 12 healthy men and women. The results were related to the clinicopathologic data on prostate volume, tumour stage, Gleason score, and prostate specific antigen (PSA).

Measurements

Sarcosine in urine was determined by gas chromatography-mass spectrometry using a commercial amino acid assay and was normalised to urine creatinine. Nonparametric statistical tests and receiver operating characteristics (ROC) analyses were performed to assess the diagnostic performance.

Results and limitations

The median sarcosine-creatinine ratio in urine was 13% lower in PCa than in NEM patients. Sarcosine values were not associated with tumour stage (pT2 vs pT3) or grade (Gleason score <7 vs ≥7). ROC analyses proved that the discrimination between PCa and NEM patients was not improved by sarcosine in comparison with total PSA, but it was significantly worse than the percent free PSA. The higher proportion of PCa than NEM patients can be considered a limitation of this study.

Conclusions

Sarcosine in urine after rectal digital examination cannot be considered as a suitable marker to differentiate between patients with and without PCa.     

Should Pathologists Routinely Report Prostate Tumour Volume? The Prognostic Value of Tumour Volume in Prostate Cancer

Background

The independent prognostic value of tumour volume in radical prostatectomy (RP) specimens is controversial, and it remains a matter of debate whether pathologists should report a measure of tumour volume. In addition, tumour volume might be of value in substaging of pathologic tumour stage (pT2) prostate cancer (PCa).

Objective

To assess the prognostic value of PCa tumour volume.

Design, setting, and participants

The cohort consisted of 344 participants in the European Randomised Study of Screening for Prostate Cancer (ERSPC), Rotterdam section, whose PCa was treated with RP. Mean time of follow-up was 96.2 mo.

Measurements

Tumour volume was measured in totally embedded RP specimens with a morphometric, computer-assisted method and assessed as a continuous variable, as relative tumour volume (tumour volume divided by prostate volume), and in a binary fashion (≥0.5 ml or <0.5 ml). These variables were related to prostate-specific antigen (PSA) progression, local recurrence, or distant metastasis and PCa-related mortality using univariate and multivariable Cox proportional hazards analyses. The analyses were repeated in the subgroup with pT2 tumours.

Results and limitations

Tumour volume was related to tumour stage, Gleason score, seminal vesicle invasion (SVI), and surgical margin status. In univariate analyses, tumour volume and relative tumour volume were predictive for all outcome variables. In multivariable analyses, including age, tumour stage, Gleason score, SVI, and surgical margin status, neither tumour volume nor relative volume were independent predictors of progression or mortality. Tumour volume ≥0.5 ml was predictive for PSA recurrence and local and/or distant progression in univariate analyses but not in multivariable analyses. Tumour volume was not predictive for recurrence or mortality in univariate or multivariable analyses in the pT2 subgroup.

Conclusions

Tumour volume did not add prognostic value to routinely assessed pathologic parameters. Therefore, there seems to be little reason to routinely measure tumour volume in RP specimens.     

Natural History of Early,Localized Prostate Cancer: A Final Report from Three Decades of Follow-up

Background

Most localized prostate cancers are believed to have an indolent course. Within 15 yr of diagnosis, most deaths among men with prostate cancer (PCa) can be attributed to other competing causes. However, data from studies with extended follow-up are insufficient to determine appropriate treatment for men with localized disease.

Objective

To investigate the long-term natural history of untreated, early-stage PCa.

Design, setting, and participants

We conducted a population-based, prospective-cohort study using a consecutive sample of 223 patients with untreated, localized PCa from a regionally well-defined catchment area in central Sweden. All subjects were initially managed with observation. Androgen deprivation therapy was administered when symptomatic tumor progression occurred.

Outcome measurements and statistical analysis

Based on >30 yr of follow-up, the main outcome measures were: progression-free, cause-specific, and overall survival, and rates of progression and mortality per 1000 person-years.

Results and limitations

After 32 yr of follow-up, all but 3 (1%) of the 223 men had died. We observed 90 (41.4%) local progression events and 41 (18.4%) cases of progression to distant metastasis. In total, 38 (17%) men died of PCa. Cause-specific survival decreased between 15 and 20 yr, but stabilized with further follow-up. All nine men with Gleason grade 8–10 disease died within the first 10 yr of follow-up, five (55%) from PCa. Survival for men with well-differentiated, nonpalpable tumors declined slowly through 20 yr, and more rapidly between 20 and 25 yr (from 75.2% [95% confidence interval, 48.4–89.3] to 25% [95% confidence interval, 22.0–72.5]). It is unclear whether these data are relevant for tumors detected by elevated prostate-specific antigen levels.

Conclusions

Although localized PCa most often has an indolent course, local progression and distant metastasis can develop over the long term, even among patients considered low risk at diagnosis.     

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.     

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.     

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.     

Expression of androgen and oestrogen receptors and its prognostic significance in urothelial neoplasm of the urinary bladder

What's known on the subject? and What does the study add? Steroid hormone receptor signals have been implicated in bladder tumourigenesis and tumour progression. The expression of androgen and/or oestrogen receptors has been assessed in bladder cancer, leading to conflicting data of expression levels and their relationship to histopathological characteristics of the tumours. We simultaneously analyze three receptors in non‐neoplastic bladder tissues as well as in primary and metastatic bladder tumour specimens. Our data demonstrate that the expression status correlates with tumour grades/stages and patients’ outcomes.

OBJECTIVE

• ? To assess the expression of the androgen receptor (AR) and oestrogen receptors (ERs) in bladder tumours because recent studies have shown conflicting results and the prognostic significance of their expression remains unclear.

PATIENTS AND METHODS

• ? We investigated the expression of AR, ERα and ERβ in 188 bladder tumour specimens, as well as matched 141 non‐neoplastic bladder and 14 lymph node metastasis tissues, by immunohistochemistry.
• ? We then evaluated the relationships between their expression and the clinicopathological features available for the present patient cohort.

RESULTS

• ? AR/ERα/ERβ was positive in 80%/50%/89% of benign urothelium, 50%/67%/41% of benign stroma, 42%/27%/49% of primary tumours and 71%/64%/71% of metastatic tumours.
• ? Significantly lower expression of AR/ERα was found in high‐grade tumours (36%/23%) and tumours invading muscularis propria (33%/19%) compared to low‐grade tumours (55%; P= 0.0232/38%; P= 0.0483) and tumours not invading muscularis propria (51%; P= 0.0181/35%; P= 0.0139), respectively.
• ? Significantly higher expression of ERβ was found in high‐grade tumours (58%) and tumours invading muscularis propria (67%) compared to low‐grade tumours (29%; P= 0.0002) and tumours not invading muscularis propria (34%; P < 0.0001), respectively.
• ? Kaplan–Meier and log‐rank tests further showed that positivity of ERβ (but not AR or ERα) was associated with the recurrence of low‐grade tumours (P= 0.0072); the progression of low‐grade tumours (P= 0.0005), high‐grade tumours not invading muscularis propria (P= 0.0020) and tumours invading muscularis propria (P= 0.0010); or disease‐specific mortality in patients with tumours invading muscularis propria (P= 0.0073).

CONCLUSIONS

• ? Compared to benign bladders, a significant decrease in the expression of AR, ERα or ERβ in bladder cancer was seen.
• ? Loss of AR or ERα was strongly associated with higher grade/more invasive tumours, whereas ERβ expression was increased in high‐grade/invasive tumours and predicted a worse prognosis.

     

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).     

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.     

Age-Specific Risk of Incident Prostate Cancer and Risk of Death from Prostate Cancer Defined by the Number of Affected Family Members

Background

The thorough assessment of familial prostate cancer (PCa) risk is as important as ever to provide a basis for clinical counselling and screening recommendations.

Objective

Our aim was to determine the age-specific risks of PCa and the risk of death from PCa according to the number and the age of affected first-degree relatives.

Design, setting, and participants

The nationwide Swedish Family-Cancer Database includes a record of >11.8 million individuals and their cancers from 1958 to 2006. All men from the database with identified parents (>3.9 million individuals) were followed between 1961 and 2006. The study included 26 651 PCa patients, of whom 5623 were familial.

Measurements

The age-specific hazard ratios (HRs) of PCa and the HRs of death from PCa were calculated according to the number and age of affected fathers and brothers.

Results and limitations

The HRs of PCa diagnosis increased with the number of affected relatives and decreased with increasing age. The highest HRs were observed for men <65 yr of age with three affected brothers (HR: approximately 23) and the lowest for men between 65 and 74 yr of age with an affected father (HR: approximately 1.8). The HRs increased with decreasing paternal or fraternal diagnostic age. The pattern of the risk of death from familial PCa was similar to the incidence data.

Conclusions

The present results should guide clinical counselling and demonstrate the vast increases in risk when multiple first-degree relatives are affected.