Validation of the contemporary epstein criteria for insignificant prostate cancer in European men

Objectives

The Epstein criteria represent the most widely used scheme for prediction of clinically insignificant prostate cancer (PCa). However, they were never validated in European men. We assessed the rate of unfavorable prostate cancer (Gleason 7–10 or non–organ-confined disease) in a cohort of 366 men who fulfilled the Epstein clinically insignificant PCa criteria.

Methods

Between 1996 and 2006, 2580 men underwent radical prostatectomy at a single academic European institution. Of those, 366 fulfilled the contemporary Epstein clinically insignificant PCa criteria. Analyses targeted the rate of pathologically unfavorable prostate cancer, defined as either Gleason sum 7–10 or non–organ-confined disease, or a combination of these characteristics in patients with clinically insignificant PCa.

Results

Gleason 7–10 prostate cancer at radical prostatectomy was found in 88 patients (24%) with clinically insignificant PCa. In addition, 30 (34.1%) of the 88 patients harboured non–organ-confined disease. Consequently, the contemporary Epstein criteria for clinically insignificant PCa were inaccurate in 24% of patients.

Conclusions

The Epstein clinical insignificant PCa criteria may underestimate the true nature of prostate cancer in as many as 24% of European patients. Therefore, caution is advised when treatment decisions are based solely on these criteria.     

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.     

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.     

Critical assessment of preoperative urinary prostate cancer antigen 3 on the accuracy of prostate cancer staging

Background

Knowledge about the staging significance of the prostate cancer antigen 3 (PCA3) score to better identify pathologic features after radical prostatectomy (RP) is limited and controversial.

Objective

Our aim was to study the clinical staging significance of PCA3 to identify pathologic favorable and/or unfavorable features in the RP specimen.

Design, setting, and participants

Complete retrospective clinical and pathologic data of consecutive men who had undergone RP from three tertiary referral centers including preoperative PCA3 scores (n = 305) and computer-assisted planimetrically measured tumor volume data (n = 160) were available.

Intervention

All patients were treated with RP.

Measurements

PCA3 scores were assessed using the PROGENSA assay (Gen-Probe, San Diego, CA, USA). Beyond standard risk factors (age, digital rectal examination, prostate-specific antigen, prostate volume, biopsy Gleason score, percentage of positive cores), five different PCA3 codings were used in logistic regression models to identify five distinct pathologic end points: (1) low-volume disease (<0.5 ml), (2) insignificant prostate cancer (PCa) according to the Epstein criteria, (3) extracapsular extension (ECE), (4) seminal vesicle invasion (SVI), and (5) aggressive disease defined as Gleason sum ≥7. Accuracy estimates of each end point were quantified using the area under the curve (AUC) of the receiver operator characteristic analysis in models with and without PCA3.

Results and limitations

PCA3 scores were significantly lower in low-volume disease and insignificant PCa (p ≤ 0.001). AUC of multivariable low-volume disease (+2.4 to +5.5%) and insignificant PCa models (+3 to +3.9%) increased when PCA3 was added to standard clinical risk factors. In contradistinction, regardless of its coding, PCA3 scores were not significantly elevated in pathologically confirmed ECE (p = 0.4) or SVI (p = 0.5), respectively. Higher PCA3 scores were associated with aggressive disease (p < 0.001). Importantly, the addition of PCA3 to multivariable intermediate- and high-grade models did not improve prediction. Despite reporting the largest pathologic PCA3 study, the main limitation resides in its small sample size.

Conclusions

PCA3 was confirmed as a valuable predictor of pathologically confirmed low-volume disease and insignificant PCa. Further exploration of its role as an additional marker to select patients for active surveillance may be warranted. In contradistinction, assessment of pathologically advanced or aggressive PCa is not improved using PCA3.     

Salvage cryoablation for locally recurrent prostate cancer following primary radiotherapy

Context

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

Objective

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

Evidence acquisition

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

Evidence synthesis

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

Conclusions

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

The Role of Biopsy Core Number in Selecting Prostate Cancer Patients for Active Surveillance

Background

Studies offer wide variations in inclusion criteria for active surveillance (AS) in prostate cancer (PCa), but the role of the biopsy core number has not been thoroughly assessed.

Objective

To evaluate the impact of the biopsy core number on the risk of misclassification for AS eligibility.

Design, setting, and participants

: This prospective study included 411 men eligible for AS who fulfilled at least one of four of the criteria reported in the literature groupings among a screening cohort of 2917 patients.

Intervention

All patients underwent a 21-core biopsy with cores mapped by location and acted as controls of themselves for the analysis of biopsy core number (6-, 12- and 21-core schemes). Radical prostatectomy (RP) was performed in 297 men (72%).

Measurements

The number of included patients, PCa extent on biopsy, rate of unfavorable disease in RP specimens, and biochemical recurrence-free survival were compared as a function of (1) the different criteria groupings for AS and (2) the biopsy core number (6, 12, or 21).

Results and limitations

Of the 1104 patients with PCa, the proportion eligible for AS ranged from 22.5% to 35.4% based on AS criteria. In men who fulfilled AS criteria only in a 12-core strategy, tumor length and percentage of cancer involvement on biopsy were significantly greater than in those who fulfilled AS criteria in a 21-core scheme. The rate of unfavorable disease on RP specimens was also higher in the former group, from 28.6% to 35.9% relative to AS criteria (p = 0.014, 0.044, and 0.113 in groups 2, 3, and 4, respectively).

Conclusions

Men eligible for AS based on a 21-core strategy have cancers with a lower extent of disease on biopsies and a lower risk of unfavorable disease on RP specimens regardless of how AS criteria are defined, compared with men eligible in a 12-core scheme.     

Pathologic prostate cancer characteristics in patients eligible for active surveillance: a head-to-head comparison of contemporary protocols

Background

Although the rationale for active surveillance (AS) in patients with low-risk prostate cancer is well established, eligibility criteria vary significantly across different programs.

Objective

To compare the ability of contemporary AS criteria to identify patients with certain pathologic tumor features based on the results of an extended transrectal prostate biopsy.

Design, settings, and participants

The study cohort included 391 radical prostatectomy patients who had prostate cancer with Gleason scores ≤6 on transrectal biopsy with ≥10 cores.

Intervention

Radical prostatectomy without neoadjuvant treatment.

Outcome measurements and statistical analysis

We identified patients who fulfilled the inclusion criteria of five AS protocols including those of Epstein, Memorial Sloan-Kettering Cancer Center, Prostate Cancer Research International: Active Surveillance (PRIAS), University of California, San Francisco, and University of Miami (UM). We evaluated the ability of these criteria to predict three pathologic end points: insignificant disease defined using a classical and updated formulation, and organ-confined Gleason ≤6 prostate cancer. Measures of diagnostic accuracy and areas under the receiver operating curve were calculated for each protocol and compared.

Results and limitations

A total of 75% of the patients met the inclusion criteria of at least one protocol; 23% were eligible for AS by all studied criteria. The PRIAS and UM criteria had the best balance between sensitivity and specificity for both definitions of insignificant prostate cancer and a higher discriminative ability for the end points than any criteria including patients with two or more positive cores. The Epstein criteria demonstrated high specificity but low sensitivity for all pathologic end points, and therefore the discriminative ability was not superior to those of other protocols.

Conclusions

Significant variations exist in the ability of contemporary AS criteria to predict pathologically insignificant prostate cancer at radical prostatectomy. These differences should be taken into account when making treatment choices in patients with low-risk prostate cancer.     

Might Men Diagnosed with Metastatic Prostate Cancer Benefit from Definitive Treatment of the Primary Tumor? A SEER-Based Study

Background

Few data exist regarding the impact on survival of definitive treatment of the prostate in men diagnosed with metastatic prostate cancer (mPCa).

Objective

To evaluate the survival of men diagnosed with mPCa based on definitive treatment of the prostate.

Design, setting, and participants

Men with documented stage IV (M1a–c) PCa at diagnosis identified using Surveillance Epidemiology and End Results (SEER) (2004–2010) and divided based on definitive treatment of the prostate (radical prostatectomy [RP] or brachytherapy [BT]) or no surgery or radiation therapy (NSR).

Outcome measurements and statistical analysis

Kaplan-Meier methods were used to calculate overall survival (OS). Multivariable competing risks regression analysis was used to calculate disease-specific survival (DSS) probability and identify factors associated with cause-specific mortality (CSM).

Results and limitations

A total of 8185 patients were identified: NSR (n = 7811), RP (n = 245), and BT (n = 129). The 5-yr OS and predicted DSS were each significantly higher in patients undergoing RP (67.4% and 75.8%, respectively) or BT (52.6 and 61.3%, respectively) compared with NSR patients (22.5% and 48.7%, respectively) (p < 0.001). Undergoing RP or BT was each independently associated with decreased CSM (p < 0.01). Similar results were noted regardless of the American Joint Committee on Cancer (AJCC) M stage. Factors associated with increased CSM in patients undergoing local therapy included AJCC T4 stage, high-grade disease, prostate-specific antigen ≥20 ng/ml, age ≥70 yr, and pelvic lymphadenopathy (p < 0.05). The major limitation of this study was the lack of variables from SEER known to influence survival of patients with mPCa, including treatment with systemic therapy.

Conclusions

Definitive treatment of the prostate in men diagnosed with mPCa suggests a survival benefit in this large population-based study. These results should serve as a foundation for future prospective trials.

Patient summary

We used a large population-based cancer database to examine survival in men diagnosed with metastatic prostate cancer (mPCa) undergoing definitive therapy for the prostate. Local therapy (LT) appeared to confer a survival benefit. Therefore, we conclude that prospective trials are needed to further evaluate the role of LT in mPCa.     

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

Context

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

Objective

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

Evidence acquisition

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

Evidence synthesis

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

Conclusions

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

Patient summary

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

Timing of Curative Treatment for Prostate Cancer: A Systematic Review

Context

Delaying definitive therapy unfavourably affects outcomes in many malignancies. Diagnostic, psychological, and logistical reasons but also active surveillance (AS) strategies can lead to treatment delay, an increase in the interval between the diagnosis and treatment of prostate cancer (PCa).

Objective

To review and summarise the current literature on the impact of treatment delay on PCa oncologic outcomes.

Evidence acquisition

A comprehensive search of PubMed and Embase databases until 30 September 2012 was performed. Studies comparing pathologic, biochemical recurrence (BCR), and mortality outcomes between patients receiving direct and delayed curative treatment were included. Studies presenting single-arm results following AS were excluded.

Evidence synthesis

Seventeen studies were included: 13 on radical prostatectomy, 3 on radiation therapy, and 1 combined both. A total of 34 517 PCa patients receiving radical local therapy between 1981 and 2009 were described. Some studies included low-risk PCa only; others included a wider spectrum of disease. Four studies found a significant effect of treatment delay on outcomes in multivariate analysis. Two included low-risk patients only, but it was unknown whether AS was applied or repeat biopsy triggered active therapy during AS. The two other studies found a negative effect on BCR rates of 2.5–9 mo delay in higher risk patients (respectively defined as any with T ≥2b, prostate-specific antigen >10, Gleason score >6, >34–50% positive cores; or D’Amico intermediate risk-group). All studies were retrospective and nonrandomised. Reasons for delay were not always clear, and time-to-event analyses may be subject to bias.

Conclusions

Treatment delay of several months or even years does not appear to affect outcomes of men with low-risk PCa. Limited data suggest treatment delay may have an impact on men with non–low-risk PCa. Most AS protocols suggest a confirmatory biopsy to avoid delaying treatment in those who harbour higher risk disease that was initially misclassified.     

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.     

Image-Guided Prostate Biopsy Using Magnetic Resonance Imaging–Derived Targets: A Systematic Review

Context

Technical improvements in prostate magnetic resonance imaging (MRI) have resulted in the use of MRI to target prostate biopsies.

Objective

To systematically review the literature to compare the accuracy of MRI-targeted biopsy with standard transrectal biopsy in the detection of clinically significant prostate cancer.

Evidence acquisition

The PubMed, Embase, and Cochrane databases were searched from inception until December 3, 2011, using the search criteria ‘prostate OR prostate cancer’ AND ‘magnetic resonance imaging OR MRI’ AND ‘biopsy OR target’. Four reviewers independently assessed 4222 records; 222 records required full review. Fifty unique records (corresponding to 16 discrete patient populations) directly compared an MRI-targeted with a standard transrectal approach.

Evidence synthesis

Evidence synthesis was used to address specific questions. Where MRI was applied to all biopsy-naive men, 62% (374 of 599) had MRI abnormalities. When subjected to a targeted biopsy, 66% (248 of 374) had prostate cancer detected. Both targeted and standard biopsy detected clinically significant cancer in 43% (236 or 237 of 555, respectively). Missed clinically significant cancers occurred in 13 men using targeted biopsy and 12 using a standard approach. Targeted biopsy was more efficient. A third fewer men were biopsied overall. Those who had biopsy required a mean of 3.8 targeted cores compared with 12 standard cores. A targeted approach avoided the diagnosis of clinically insignificant cancer in 53 of 555 (10%) of the presenting population.

Conclusions

MRI-guided biopsy detects clinically significant prostate cancer in an equivalent number of men versus standard biopsy. This is achieved using fewer biopsies in fewer men, with a reduction in the diagnosis of clinically insignificant cancer. Variability in study methodology limits the strength of recommendation that can be made. There is a need for a robust multicentre trial of targeted biopsies.     

High-risk prostate cancer: from definition to contemporary management

Context

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

Objective

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

Evidence acquisition

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

Evidence synthesis

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

Conclusions

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

Focal Therapy for Prostate Cancer: Possibilities and Limitations

Context

A significant proportion of patients diagnosed with prostate cancer have well-differentiated, low-volume tumors at minimal risk of impacting their quality of life or longevity. The selection of a treatment strategy, among the multitude of options, has enormous implications for individuals and health care systems.

Objective

Our aim was to review the rationale, patient selection criteria, diagnostic imaging, biopsy schemes, and treatment modalities available for the focal therapy of localized prostate cancer. We gave particular emphasis to the conceptual possibilities and limitations.

Evidence acquisition

A National Center for Biotechnology Information PubMed search (www.pubmed.gov) was performed from 1995 to 2009 using medical subject headings “focal therapy” or “ablative” and “prostate cancer.” Additional articles were extracted based on recommendations from an expert panel of authors.

Evidence synthesis

Focal therapy of the prostate in patients with low-risk cancer characteristics is a proposed treatment approach in development that aims to eradicate all known foci of cancer while minimizing damage to adjacent structures necessary for the preservation of urinary, sexual, and bowel function. Conceptually, focal therapy has the potential to minimize treatment-related toxicity without compromising cancer-specific outcome. Limitations include the inability to stage or grade the cancer(s) accurately, suboptimal imaging capabilities, uncertainty regarding the natural history of untreated cancer foci, challenges with posttreatment monitoring, and the lack of quality-of-life data compared with alternative treatment strategies. Early clinical experiences with modest follow-up evaluating a variety of modalities are encouraging but hampered by study design limitations and small sample sizes.

Conclusions

Prostate focal therapy is a promising and emerging treatment strategy for men with a low risk of cancer progression or metastasis. Evaluation in formal prospective clinical trials is essential before this new strategy is accepted in clinical practice. Adequate trials must include appropriate end points, whether absence of cancer on biopsy or reduction in progression of cancer, along with assessments of safety and longitudinal alterations in quality of life.     

Concordance of tumor differentiation among brothers with prostate cancer

Background

Genetic factors seem to be of greater importance in prostate cancer than in other forms of cancer. Studies have suggested familial concordance in survival, but the extent to which that is due to tumor characteristics is not known.

Objective

We hypothesized that a brother of an index case with prostate cancer is at particularly increased risk of prostate cancer with the same tumor differentiation as the index case.

Design, setting and participants

We identified 21 930 brothers of index cases with prostate cancer in the Prostate Cancer Data Base Sweden and followed them up for incidence of prostate cancer.

Outcome measurements and statistical analysis

The relative risk of Gleason score–specific prostate cancer in the cohort of brothers was estimated by using the standardized incidence ratio (SIR) stratified by Gleason score of the index case. We estimated 95% confidence intervals (CIs) assuming a Poisson distribution.

Results and limitations

Among brothers of index cases with Gleason score 8–10 cancer, the SIR was 2.53 (95% CI, 1.97–3.21) for a Gleason score 2–6 cancer and 4.00 (95% CI, 2.63–5.82) for a Gleason score 8–10 cancer. SIR for Gleason score 2–6 cancer among brothers decreased with time since the date of the index cases’ diagnoses, whereas the risk of Gleason 8–10 cancer increased over time for brothers of index cases with Gleason 8–10 cancer (p for trend = 0.009).

Conclusions

Brothers of men with high-grade prostate cancer are at particularly increased risk of high-grade prostate cancer. Likewise, there is a concordance of less malignant prostate cancers within families. These findings may have direct clinical relevance for counseling men with a family history of prostate cancer.     

Systematic Review of the Efficacy and Safety of High-Intensity Focussed Ultrasound for the Primary and Salvage Treatment of Prostate Cancer

Context

High-intensity focussed ultrasound (HIFU) is an emerging minimally invasive treatment option for prostate cancer.

Objective

Our aim was to assess the efficacy and safety of HIFU in both primary treatment of men with localised and locally advanced prostate cancer as well as salvage treatment of men with recurrent prostate cancer following treatment failure of radical prostatectomy or external-beam radiation therapy.

Evidence acquisition

We conducted a systematic literature search for studies conducted on humans and published in either English or German in several databases from 2000 to 2010. In addition, we screened several Web sites for assessments on HIFU in prostate cancer and contacted the manufacturers of the two currently available HIFU devices for supplemental information on HIFU. We included all prospective studies with >50 study participants and assessed their quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Evidence synthesis

We identified 20 uncontrolled prospective case series, each of which treated between 58 and 517 patients. These studies were all conducted within the past decade. In total, 3018 patients were treated with HIFU, 93% for primary therapy and 7% for salvage HIFU. For all HIFU procedures, the biochemical disease-free survival rate at 1, 5, and 7 yr, respectively, was 78–84%, 45–84%, and 69%. The negative biopsy rate was 86% at 3 mo and 80% at 15 mo. Overall survival rates and prostate cancer–specific survival rates were 90% and 100% at 5 yr and 83% and 98% at 8 yr, respectively. Adverse events concerned the urinary tract (1–58%), potency (1–77%), the rectum (0–15%), and pain (1–6%). Quality-of-life assessment yielded controversial results.

Conclusions

Applying the GRADE approach, the available evidence on efficacy and safety of HIFU in prostate cancer is of very low quality, mainly due to study designs that lack control groups. More research is needed to explore the use of HIFU in prostate cancer.     

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.     

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).