Prostate cancer detection and dutasteride: utility and limitations of prostate-specific antigen in men with previous negative biopsies

Context

We addressed the question whether the change of serum prostate-specific antigen (PSA) in men who use 5α-reductase inhibitor (5-ARI) dutasteride is sensitive for the detection of aggressive prostate cancer (PCa).

Objective

The case of a man using dutasteride diagnosed with Gleason 7 transition zone cancer at biopsy indicated by a rising PSA is described. The following issues are discussed: (1) Is a rise of PSA in patients using dutasteride predictive of aggressive PCa in men with prior negative biopsies? (2) Is it safe not to biopsy men using dutasteride who do not show a rising PSA? (3) How can we avoid potentially unnecessary biopsies in men using dutasteride without a rising PSA?

Evidence acquisition

We reviewed the recent literature addressing our objective that relates to two studies: the Prostate Cancer Prevention Trial and the Reduction by Dutasteride of Prostate Cancer Events trial.

Evidence synthesis

In men using dutasteride, the positive predictive value/detection rate of Gleason 7–10 PCa is 13.2% and 4.0% for men with and without a rising PSA, respectively. However, a substantial proportion of Gleason 7–10 cases (42.9%) would be missed if a rising PSA was used as the only biopsy indication. Currently available data do not provide selective mechanisms to diagnose these cancers.

Conclusions

A rising PSA for a patient using dutasteride should be an indication for prostate biopsies. Currently, in the case of stable PSA a biopsy may still be considered. Options for a selective approach are therefore suggested in this review to avoid unnecessary biopsies and to achieve a more selective PCa detection in men on 5-ARI treatment.     

Impact of 5α-reductase inhibitors on men followed by active surveillance for prostate cancer

Background

In two large randomized controlled trials, 5α-reductase inhibitors (5-ARIs) were shown to prevent prostate cancer. No prior work had shown the effect of 5-ARIs on those already diagnosed with low-risk prostate cancer.

Objective

Our aim was to determine the effect of 5-ARIs on pathologic progression in men on active surveillance.

Design, setting, and participants

We conducted a single-institution retrospective cohort study comparing men taking a 5-ARI versus no 5-ARI while on active surveillance for prostate cancer.

Measurements

Pathologic progression was evaluated and defined as Gleason score >6, maximum core involvement >50%, or more than three cores positive on a follow-up prostate biopsy. Kaplan-Meier analyses were conducted along with multivariable Cox proportional hazard regression modeling for predictors of pathologic progression.

Results and limitations

A total of 288 men on active surveillance met the inclusion criteria. The median follow-up was 38.5 mo (interquartile range: 23.6–59.4) with 93 men (32%) experiencing pathologic progression and 96 men (33%) abandoning active surveillance. Men taking a 5-ARI experienced a lower rate of pathologic progression (18.6% vs 36.7%; p = 0.004) and were less likely to abandon active surveillance (20% vs 37.6%; p = 0.006). On multivariable Cox proportional hazards analysis, lack of 5-ARI use was most strongly associated with pathologic progression (hazard ratio: 2.91; 95% confidence interval, 1.5–5.6). The main study limitation was the retrospective design and variable duration of 5-ARI therapy.

Conclusions

The 5-ARIs were associated with a significantly lower rate of pathologic progression and abandonment of active surveillance.     

Pharmacological Approaches to Reducing the Risk of Prostate Cancer

Context

It is now possible to reduce a man's risk of developing biopsy-detectable prostate cancer. This review addresses the evidence and issues surrounding prostate cancer risk reduction.

Objective

The scientific basis, therapeutic approach, and risks and benefits of prostate cancer prevention are reviewed. Special attention is given to data on 5α-reductase inhibitors (5-ARIs).

Evidence acquisition

Medline searches consisted of articles published since 2003 regarding prostate cancer chemoprevention, prevention, or risk reduction, as well as searches around specific topics within this review.

Evidence synthesis

Current data support the use of finasteride for prostate cancer risk reduction in appropriately selected men. The initial concern that finasteride increased the incidence of high-grade prostate cancer has not been confirmed by subsequent analyses. The efficacy of dutasteride, a dual 5-ARI, for prostate cancer risk reduction is currently being evaluated in men with elevated prostate-specific antigen (PSA). Other medical approaches to prostate cancer risk reduction, including statins, cyclooxygenase-2 (COX-2) inhibitors, selective estrogen receptor modulators, and dietary supplements, await validation in controlled clinical trials.

Conclusions

It is now possible to reduce an individual man's risk of developing biopsy-detectable prostate cancer. The greatest benefit arises from decreasing the amount of unnecessary treatment in men harboring low-risk cancers. Presently, there is no evidence that 5-ARIs or any other approach to prostate cancer risk reduction will reduce the risk of lethal prostate cancers. Finasteride, however, does enhance the utility of PSA for diagnosing high-grade cancers.     

Effect of dutasteride on prostate biopsy rates and the diagnosis of prostate cancer in men with lower urinary tract symptoms and enlarged prostates in the Combination of Avodart and Tamsulosin trial

Background

A 23% relative risk reduction (RRR) in prostate cancer (PCa) was shown in men receiving dutasteride in the 4-yr Reduction by Dutasteride of Prostate Cancer Events study, in whom biopsies were protocol dependent.

Objective

Our aim was to explore PCa risk reduction in men with benign prostatic hyperplasia (BPH) from the Combination of Avodart and Tamsulosin (CombAT) study, in which biopsies were undertaken for cause.

Design, setting, and participants

CombAT was a 4-yr randomized double-blind parallel group study in 4844 men ≥50 yr of age with clinically diagnosed moderate to severe BPH, International Prostate Symptom Score ≥12, prostate volume ≥30 ml, and serum prostate-specific antigen (PSA) 1.5–10 ng/ml. Men underwent annual PSA measurement and digital rectal examination (DRE), and prostate biopsies were performed for cause.

Intervention

All patients took tamsulosin 0.4 mg/d, dutasteride 0.5 mg/d, or a combination of both.

Measurements

The primary end point was incidence of PCa. Secondary end points included postbaseline prostate biopsy rates and Gleason score of cancers.

Results and limitations

Dutasteride (alone or in combination with tamsulosin) was associated with a 40% RRR of PCa diagnosis compared with tamsulosin monotherapy (95% confidence interval, 16–57%; p = 0.002) and a 40% reduction in the likelihood of biopsy. There were similar reductions in low- and high-grade Gleason score cancers. The biopsy rate in the groups receiving dutasteride trended toward a higher diagnostic yield (combination: 29%, dutasteride: 28%, tamsulosin: 24%). One limitation was the lack of a standardized approach to PCa diagnosis and grading.

Conclusions

Dutasteride, alone or in combination with tamsulosin, significantly reduced the relative risk of PCa diagnosis in men with BPH undergoing annual DRE and PSA screening. Consistent with the increased usefulness of PSA for PCa detection, men receiving dutasteride had a numerically lower biopsy rate and higher yield of PCa on biopsy.

Trial registration

Clinicaltrials.gov identifier: NCT00090103 (http://www.clinicaltrials.gov/ct2/show/NCT00090103).     

Dutasteride Treatment Over 2 Years Delays Prostate-specific Antigen Progression in Patients with Biochemical Failure After Radical Therapy for Prostate Cancer: Results from the Randomised,Placebo-controlled Avodart After Radical Therapy for Prostate Cancer Study (ARTS)

Background

Rising prostate-specific antigen (PSA) levels after radical therapy are indicative of recurrent or residual prostate cancer (PCa). This biochemical recurrence typically predates clinically detectable metastatic disease by several years. Management of patients with biochemical recurrence is controversial.

Objective

To assess the effect of dutasteride on progression of PCa in patients with biochemical failure after radical therapy.

Design, setting, and participants

Randomised, double-blind, placebo-controlled trial in 294 men from 64 centres across 9 European countries.

Intervention

The 5α-reductase inhibitor, dutasteride.

Outcome measurements and statistical analysis

The primary end point was time to PSA doubling from start of randomised treatment, analysed by log-rank test stratified by previous therapy and investigative-site cluster. Secondary end points included time to disease progression and the proportion of subjects with disease progression.

Results and limitations

Of the 294 subjects randomised (147 in each treatment group), 187 (64%) completed 24 mo of treatment and 107 discontinued treatment prematurely (71 [48%] of the placebo group, 36 [24%] of the dutasteride group). Dutasteride significantly delayed the time to PSA doubling compared with placebo after 24 mo of treatment (p < 0.001); the relative risk (RR) reduction was 66.1% (95% confidence interval [CI], 50.35–76.90) for the overall study period. Dutasteride also significantly delayed disease progression (which included PSA- and non-PSA-related outcomes) compared with placebo (p < 0.001); the overall RR reduction in favour of dutasteride was 59% (95% CI, 32.53–75.09). The incidence of adverse events (AEs), serious AEs, and AEs leading to study withdrawal were similar between the treatment groups. A limitation was that investigators were not blinded to PSA levels during the study.

Conclusions

Dutasteride delayed the biochemical progression of PCa in patients with biochemical failure after radical therapy for clinically localised disease. The safety and tolerability of dutasteride were generally consistent with previous experience.

Clinical trial registry

ClinicalTrials.gov, NCT00558363.     

Serum Testosterone and Dihydrotestosterone and Prostate Cancer Risk in the Placebo Arm of the Reduction by Dutasteride of Prostate Cancer Events Trial

Background

Findings of studies on the association between androgens and prostate cancer (PCa) are mixed. Androgens may affect prostate-specific antigen (PSA) levels, thereby influencing biopsy recommendations. Also, androgens may stimulate prostate growth at very low levels with no additional effects at higher levels (saturation model).

Objective

To test whether androgens were associated with PCa risk in the placebo arm of a prospective study in which biopsies were performed regardless of PSA level.

Design, setting, and participants

Of 8122 men in the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, 4073 men (50.1%) received placebo. Key entry criteria were PSA 2.5–10 ng/ml and one prior negative biopsy.

Intervention

Per-protocol biopsies at 2 and 4 yr; for-cause biopsies at physician discretion.

Outcome measurements and statistical analysis

Multivariable logistic regression was used to test the association between baseline log-transformed testosterone and dihydrotestosterone (DHT) levels and the risk of detecting either PCa or low-grade PCa (Gleason score <6) compared with high-grade PCa (Gleason score >7). In secondary analysis, we stratified the analysis by low baseline androgen levels (testosterone <10 nmol/l; DHT <0.76 nmol/l) compared with normal baseline androgen levels.

Results and limitations

Of 4073 men, 3255 (79.9%) had at least one biopsy after randomization and were analyzed. Androgen levels tested continuously or by quintiles were generally unrelated to PCa detection or grade. PCa detection was similar among men with low compared with normal baseline testosterone levels (25.5% and 25.1%; p = 0.831). In secondary analysis, higher testosterone levels at baseline were associated with higher PCa detection (odds ratio: 1.23; 95% confidence interval, 1.06–1.43; p = 0.006) only if men had low baseline testosterone (<10 nmol/l). For men with normal baseline testosterone (≥10 nmol/l), higher testosterone levels at baseline were unrelated to PCa risk (p = 0.33). No association was found for DHT and PCa (all p > 0.85).

Conclusions

Baseline serum testosterone and DHT levels were unrelated to PCa detection or grade. Our findings of the lowest testosterone levels being associated with the lowest PCa risk with no further changes with higher testosterone support a saturation model but must be confirmed in future studies using an a priori defined hypothesis.

ClinicalTrials.gov identifier

NCT00056407.     

Long-term Prostate-specific Antigen Velocity in Improved Classification of Prostate Cancer Risk and Mortality

Background

It remains unclear whether adding long-term prostate-specific antigen velocity (PSAV) to baseline PSA values improves classification of prostate cancer (PCa) risk and mortality in the general population.

Objective

To determine whether long-term PSAV improves classification of PCa risk and mortality in the general population.

Design, setting, and participants

We studied 503 men aged 30–80 yr, with and without PCa, who had repeated PSA measurements over 20 yr and up to 28 yr before PCa diagnosis. These were selected from among 7455 men in the Copenhagen City Heart Study, a prospective, general population study with follow-up from 1981 through 2010. Results were subsequently applied to all 1 351 441 men aged 40–80 yr living in Denmark from 1997 through 2006.

Outcome measurements and statistical analysis

PCa risk and mortality were assessed using Cox regression. Improvement in risk classification was assessed using the net reclassification index (NRI).

Results

Age-adjusted hazard ratios for PCa risk and mortality were 2.7–5.3 and 2.3–3.4, respectively, for long-term PSAV when added to models already including baseline PSA values. For PCa risk and mortality, adding long-term PSAV to models already including baseline PSA values and age yielded continuous NRIs of 98–99% and 56–106%, respectively. Used on a nationwide scale (eg, for men aged 60–64 yr), long-term PSAV >0.35 versus ≤0.35 ng/ml per year appropriately reclassified 128 of 10 000 men with PCa and 8095 of 10 000 men with no PCa. Correspondingly, inappropriately reclassified were 49 of 10 000 men with PCa and 1658 of 10 000 men with no PCa.

Conclusions

Long-term PSAV in addition to baseline PSA value improves classification of PCa risk and mortality. Applying long-term PSAV nationwide, the ratio of appropriately to inappropriately classified men would typically be 5:1.     

Obesity Is Associated with Increased Prostate Growth and Attenuated Prostate Volume Reduction by Dutasteride

Background

Although obesity has been associated with larger prostate volumes (PV), few studies have actually investigated whether obesity enhances PV growth, especially among men using 5α-reductase inhibitors.

Objective

To examine whether obesity is associated with enhanced PV growth measured by serial transrectal ultrasound (TRUS) measurements.

Design, setting, and participants

We conducted a secondary analysis of the REduction by DUtasteride of prostate Cancer Events (REDUCE) trial, which was originally aimed at cancer risk reduction among high-risk men with a single negative prestudy biopsy.

Intervention

Per-protocol randomization to placebo or dutasteride and mandatory TRUS-guided biopsies at 2 yr and 4 yr.

Outcome measurements and statistical analysis

Percentage change in PV at 2 yr and 4 yr from baseline. We tested its association with baseline body mass index (BMI) groups of <25, 25–29.9, and ≥30 kg/m² using multivariable linear regression. Secondarily, we tested whether BMI was associated with the likelihood of having no PV reduction among men randomized to dutasteride using multivariable logistic regression.

Results and limitations

Of 8122 participants, we analyzed 71.8% and 54.5% with complete 2-yr and 4-yr PV data, respectively. In multivariable analysis, men on placebo with BMI ≥30 versus <25 kg/m² had enhanced PV growth from baseline (at 2 yr: 17.0% vs 10.7%, p < 0.001; at 4 yr: 29.4% vs 20.1%; p = 0.001). Men on dutasteride with BMI ≥30 versus <25 kg/m² had attenuated PV reduction from baseline (at 2 yr: −14.3% vs −18.5%; p = 0.002; at 4 yr: −13.2% vs −19.3%; p = 0.001) and higher likelihood of having no PV reduction (at 2 yr: odds ratio [OR]: 1.44; 95% confidence interval [CI], 1.08–1.93; p = 0.014; at 4 yr: OR: 1.62; 95% CI, 1.18–2.22; p = 0.003). We found no significant interactions between BMI and dutasteride on PV change at 2 yr and 4 yr (p interaction ≥0.36). No clinical outcomes or effects of weight change were assessed.

Conclusions

Obesity enhanced PV growth and attenuated PV reduction by dutasteride. The null interaction between obesity and dutasteride for PV change implies that the effect of obesity on dutasteride-treated men is likely a combination of dutasteride-driven PV reduction with obesity-driven PV growth rather than decreased dutasteride efficacy.

ClinicalTrials.gov identifier

NCT00056407.     

Potential Impact of Adding Genetic Markers to Clinical Parameters in Predicting Prostate Biopsy Outcomes in Men Following an Initial Negative Biopsy: Findings from the REDUCE Trial

Background

Several germline single nucleotide polymorphisms (SNPs) have been consistently associated with prostate cancer (PCa) risk.

Objective

To determine whether there is an improvement in PCa risk prediction by adding these SNPs to existing predictors of PCa.

Design, setting, and participants

Subjects included men in the placebo arm of the randomized Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial in whom germline DNA was available. All men had an initial negative prostate biopsy and underwent study-mandated biopsies at 2 yr and 4 yr. Predictive performance of baseline clinical parameters and/or a genetic score based on 33 established PCa risk-associated SNPs was evaluated.

Outcome measurements and statistical analysis

Area under the receiver operating characteristic curves (AUC) were used to compare different models with different predictors. Net reclassification improvement (NRI) and decision curve analysis (DCA) were used to assess changes in risk prediction by adding genetic markers.

Results and limitations

Among 1654 men, genetic score was a significant predictor of positive biopsy, even after adjusting for known clinical variables and family history (p = 3.41 × 10⁻⁸). The AUC for the genetic score exceeded that of any other PCa predictor at 0.59. Adding the genetic score to the best clinical model improved the AUC from 0.62 to 0.66 (p < 0.001), reclassified PCa risk in 33% of men (NRI: 0.10; p = 0.002), resulted in higher net benefit from DCA, and decreased the number of biopsies needed to detect the same number of PCa instances. The benefit of adding the genetic score was greatest among men at intermediate risk (25th percentile to 75th percentile). Similar results were found for high-grade (Gleason score ≥7) PCa. A major limitation of this study was its focus on white patients only.

Conclusions

Adding genetic markers to current clinical parameters may improve PCa risk prediction. The improvement is modest but may be helpful for better determining the need for repeat prostate biopsy. The clinical impact of these results requires further study.     

Tumour Grade,Treatment, and Relative Survival in a Population-based Cohort of Men with Potentially Curable Prostate Cancer

Background

There is insufficient information regarding the benefit of treatment with curative intent for men with localised poorly differentiated prostate cancer (PCa).

Objective

To evaluate relative survival in men with potentially curable PCa in relation to Gleason score (GS) and treatment as practiced in the community at large.

Design, setting, and participants

A population-based study including all men with localised PCa registered in Sweden's National Prostate Cancer Register.

Interventions

Hormonal therapy, watchful waiting, and treatment with curative intent.

Measurements

The ratio of observed deaths to expected deaths, determined from survival in the general male population of the same age, was assessed using Poisson regression analysis, with GS and treatment as covariates. Interaction between GS and treatment was tested in a multivariate Cox proportional hazard analysis.

Results and limitations

A total of 31 903 men with potentially curable tumour (T1–T3, N0/NX, M0/MX, age <75 yr, and prostate-specific antigen [PSA] <20 ng/ml) were identified. GS was recorded for 28 454 of these men. Some 19 606 men (60.8%) were treated with curative intent, and 12 645 men (39.2%) were given either hormonal treatment or expectant management. The ratios between observed and expected survival gradually increased for men with GS 10, with GS to 3.3 for men treated conservatively and to 1.4 for men treated with curative intent. There was a significant interaction between GS and treatment, with a relatively greater benefit from treatment with curative intent for men with high-grade tumours. The results have to be interpreted with some caution, as there was no randomisation between the treatment groups.

Conclusions

Survival for men with well-differentiated tumours is close to that of the general population, regardless of treatment, but the outcome is dismal for men with poorly differentiated tumours, whichever treatment is applied. Nevertheless, men with poorly differentiated tumours benefit more from curative treatment than do men with well- differentiated tumours.     

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.     

Eleven-Year Outcome of Patients with Prostate Cancers Diagnosed During Screening After Initial Negative Sextant Biopsies

Background

The appropriate way of biopsying a prostate remains controversial. Is sextant biopsy still adequate with repeat screening?

Objective

Within the European Randomized Study of Screening for Prostate Cancer (ERSPC), lateralized sextant biopsies were applied. In this analysis we use distant end points to study the fate of prostate cancers (PCa) potentially missed by initial biopsies.

Design, setting, and participants

This retrospective study included 19 970 men ages 55–74 identified from the Rotterdam population registry and screened repeatedly for PCa between 1993 and 2005. PCa detected later in men with initially negative biopsies were considered as missed. Rescreening every 4 yr and a complete follow-up of 11 yr allowed an inventory of progressive and deadly disease in these men.

Intervention

Sextant biopsies initially, later lateralized, in screen-positive men.

Measurements

The fate of PCa potentially missed by initial sextant biopsies in terms of progression-free and PCa-specific survival were the main outcome measures. Kaplan-Meier analysis was used to evaluate differences between subgroups.

Results and limitations

In 3056 men with negative biopsies at the first screen, 287 PCa were subsequently detected. Of these 287 cases, 26 developed progressive disease and 7 died of PCa. Poor outcomes were encountered mainly in 20 interval cases. The seven PCa deaths in men with initially negative biopsies amounted to only 0.03% compared to the 0.35% PCa death rate in the whole population of 19 970 men. Limitations include the retrospective character of this analysis.

Conclusions

The number of potentially missed cancers with a poor outcome in terms of progression-free survival and deaths from PCa is very low. Despite some limitations, our data show that lateralized sextant biopsy is not obsolete if repeated screening is applied.     

Initial Prostate Biopsy: Development and Internal Validation of a Biopsy-specific Nomogram Based on the Prostate Cancer Antigen 3 Assay

Background

Urinary prostate cancer antigen 3 (PCA3) assay in combination with established clinical risk factors improves the identification of men at risk of harboring prostate cancer (PCa) at initial biopsy (IBX).

Objective

To develop and validate internally the first IBX-specific PCA3-based nomogram that allows an individual assessment of a man's risk of harboring any PCa and high-grade PCa (HGPCa).

Design, setting, and participants

Clinical and biopsy data including urinary PCA3 score of 692 referred IBX men at risk of PCa were collected within two prospective multi-institutional studies.

Intervention

IBX (≥10 biopsy cores) with standard risk factor assessment including prebiopsy urinary PCA3 measurement.

Outcome measurements and statistical analysis

PCA3 assay cut-off thresholds were investigated. Regression coefficients of logistic risk factor analyses were used to construct specific sets of PCA3-based nomograms to predict any PCa and HGPCa at IBX. Accuracy estimates for the presence of any PCa and HGPCa were quantified using area under the curve of the receiver operator characteristic analysis and compared with a clinical model. Bootstrap resamples were used for internal validation. Decision curve analyses quantified the clinical net benefit related to the novel PCA3-based IBX nomogram versus the clinical model.

Results and limitations

Any PCa and HGPCa were diagnosed in 46% (n = 318) and 20% (n = 137), respectively. Age, prostate-specific antigen, digital rectal examination, prostate volume, and PCA3 were independent predictors of PCa at IBX (all p < 0.001). The PCA3-based IBX nomograms significantly outperformed the clinical models without PCA3 (all p < 0.001). Accuracy was increased by 4.5–7.1% related to PCA3 inclusion. When applying nomogram-derived PCa probability thresholds ≤30%, only a few patients with HGPCa (≤2%) will be missed while avoiding up to 55% of unnecessary biopsies. External validation of the PCA3-based IBX-specific nomogram is warranted.

Conclusions

The internally validated PCA3-based IBX-specific nomogram outperforms a clinical prediction model without PCA3 for the prediction of any PCa, leading to the avoidance of unnecessary biopsies while missing only a few cases of HGPCa. Our findings support the concepts of a combination of novel markers with established clinical risk factors and the superiority of decision tools that are specific to a clinical scenario.     

Association of clinical benign prostate hyperplasia with prostate cancer incidence and mortality revisited: a nationwide cohort study of 3,009,258 men

Background

Although benign prostate hyperplasia (BPH) and prostate cancer (PCa) share features such as hormone-dependent growth and response to treatment with antiandrogen therapy, BPH is generally not considered a premalignant lesion.

Objective

To determine whether clinical BPH is associated with an increased risk of PCa incidence and mortality.

Design, setting, and participants

Using designs with individual participant data from five national registries, we studied the entire Danish male population from 1980 through 2006, a total of 3 009 258 Danish men. We collected PCa diagnoses (n = 53 315), information on PCa mortality (n = 25 459), and ascertained clinical BPH (not histologically proven BPH) through hospitalization (n = 187 591) and/or surgery (n = 77 698) from 1980 to 2006 and the use of α-adrenergic receptor antagonists (n = 143 365) and/or the use of 5α-reductase inhibitors (5-ARIs) (n = 47 465) from 1995 to 2006.

Measurements

PCa incidence and mortality was assessed for each category of clinical BPH using Kaplan-Meier plots of cumulative incidence and Cox proportional hazard ratios (HRs) adjusted for potential confounders.

Results and limitations

For the entire cohort studies, multivariate-adjusted HRs for PCa incidence were 2.22 (95% confidence interval, 2.13-2.31) in men hospitalized and 3.26 (3.03-3.50) in men operated on for clinical BPH versus general population controls. Corresponding HRs for PCa mortality were 2.00 (1.91-2.08) for hospitalization and 7.85 (7.40-8.32) for surgery. For age-matched cohort studies, corresponding HRs for PCa incidence were 3.04 (2.96-3.13) for hospitalization, 2.60 (2.47-2.73) for surgery, 4.49 (4.33-4.65) for α-adrenergic receptor antagonist use, and 2.54 (2.40-2.68) for 5-ARI use. Each category of clinical BPH has limitations, but limitations differ between the categories and therefore are unlikely to explain the results.

Conclusions

In Danish men followed for up to 27 yr, clinical BPH was associated with a two- to three-fold increased risk of PCa incidence and with a two- to eight-fold increased risk of PCa mortality. These data should not be used to infer causality.     

Outcome Following Active Surveillance of Men with Screen-detected Prostate Cancer. Results from the Göteborg Randomised Population-based Prostate Cancer Screening Trial

Background

Active surveillance (AS) has emerged as a treatment strategy for reducing overtreatment of screen-detected, low-risk prostate cancer (PCa).

Objective

To assess outcomes following AS of men with screen-detected PCa.

Design, setting, and participants

Of the 968 men who were diagnosed with screen-detected PCa between 1995 and 2010 in the Göteborg randomised, population-based PCa screening trial, 439 were managed with AS and were included in this study. Median age at diagnosis was 65.4 yr of age, and median follow-up was 6.0 yr from diagnosis.

Intervention

The study participants were followed at intervals of 3–12 mo and were recommended to switch to deferred active treatment in case of a progression in prostate-specific antigen, grade, or stage.

Outcome measurements and statistical analysis

The end points—overall survival (OS), treatment-free survival, failure-free (no relapse after radical treatment) survival, and cancer-specific survival—were calculated for various risk groups (very low, low, intermediate, and high) with Kaplan-Meier estimates. A Cox proportional hazards model as well as a competing risk analysis were used to assess whether risk group or age at diagnosis was associated with failure after AS.

Results and limitations

Forty-five per cent of all screen-detected PCa were managed with AS, and very low-risk and low-risk PCa constituted 60% of all screen-detected PCa. Thirty-seven per cent (162 of 439) switched from surveillance to deferred active treatment, and 39 men failed AS. The 10-yr OS, treatment-free survival, and failure-free survival were 81.1%, 45.4%, and 86.4%, respectively (Kaplan-Meier estimates). Men with low-, intermediate-, and high-risk tumours had a hazard ratio for failure of 2.1 (p = 0.09), 3.6 (p = 0.002), and 4.6 (p = 0.15), respectively, compared to very low-risk tumours (Cox regression). Only one PCa death occurred, and one patient developed metastasis (both in the intermediate-risk group). The main limitation of this study is the relatively short follow-up.

Conclusions

A large proportion of men with screen-detected PCa can be managed with AS. AS appears safe for men with low-risk PCa.     

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.     

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 Genetic Score Can Identify Men at High Risk for Prostate Cancer Among Men With Prostate-Specific Antigen of 1–3 ng/ml

Background

The diagnostic performance of a genetic score based on single nucleotide polymorphisms (SNPs) is unknown in the prostate-specific antigen (PSA) range of 1–3 ng/ml. A substantial proportion of men in this PSA span have prostate cancer (PCa), but biomarkers to determine who should undergo a prostate biopsy are lacking.

Objective

To evaluate whether a genetic risk score identifies men in the PSA range of 1–3 ng/ml who are at higher risk for PCa.

Design, setting, and participants

Men aged 50–69 yr with PSA 1–3 ng/ml and without a previous prostate biopsy were selected from the STHLM2 cohort. Of 2696 men, 49 SNPs were genotyped, and a polygenic risk score was calculated. Of these men, 860 were invited according to risk score, and 172 underwent biopsy.

Outcome measurements and statistical analysis

The risk of PCa was assessed using univariate and multivariate logistic regression analysis.

Results and limitations

PCa was diagnosed in 47 of 172 participants (27%), with Gleason sum 6 in 36 of 47 men (77%) and Gleason sum ≥7 in 10 of 47 men (21%); one man had intraductal cancer. The genetic score was a significant predictor of a positive biopsy (p = 0.028), even after adjusting for PSA, ratio of free to total PSA, prostate volume, age, and family history. There was an increase in the odds ratio of 1.60 (95% confidence interval, 1.05–2.45) with increasing genetic risk score. The absolute risk difference of positive biopsy was 19 percentage points, comparing the high and low genetic risk group (37% vs 18%).

Conclusions

A risk score based on SNPs predicts biopsy outcome in previously unbiopsied men with PSA 1–3 ng/ml. Introducing a genetic-based risk stratification tool can increase the proportion of men being classified in line with their true risk of PCa.     

Prostate Cancer Mortality Reduction by Prostate-Specific Antigen–Based Screening Adjusted for Nonattendance and Contamination in the European Randomised Study of Screening for Prostate Cancer (ERSPC)

Background

Prostate-specific antigen (PSA) based screening for prostate cancer (PCa) has been shown to reduce prostate specific mortality by 20% in an intention to screen (ITS) analysis in a randomised trial (European Randomised Study of Screening for Prostate Cancer [ERSPC]). This effect may be diluted by nonattendance in men randomised to the screening arm and contamination in men randomised to the control arm.

Objective

To assess the magnitude of the PCa-specific mortality reduction after adjustment for nonattendance and contamination.

Design, setting, and participants

We analysed the occurrence of PCa deaths during an average follow-up of 9 yr in 162 243 men 55–69 yr of age randomised in seven participating centres of the ERSPC. Centres were also grouped according to the type of randomisation (ie, before or after informed written consent).

Intervention

Nonattendance was defined as nonattending the initial screening round in ERSPC. The estimate of contamination was based on PSA use in controls in ERSPC Rotterdam.

Measurements

Relative risks (RRs) with 95% confidence intervals (CIs) were compared between an ITS analysis and analyses adjusting for nonattendance and contamination using a statistical method developed for this purpose.

Results and limitations

In the ITS analysis, the RR of PCa death in men allocated to the intervention arm relative to the control arm was 0.80 (95% CI, 0.68–0.96). Adjustment for nonattendance resulted in a RR of 0.73 (95% CI, 0.58–0.93), and additional adjustment for contamination using two different estimates led to estimated reductions of 0.69 (95% CI, 0.51–0.92) to 0.71 (95% CI, 0.55–0.93), respectively. Contamination data were obtained through extrapolation of single-centre data. No heterogeneity was found between the groups of centres.

Conclusions

PSA screening reduces the risk of dying of PCa by up to 31% in men actually screened. This benefit should be weighed against a degree of overdiagnosis and overtreatment inherent in PCa screening.