Active Surveillance for Prostate Cancer: A Review

Comparative pathology of dog and human prostate cancer

Though relatively rare in dogs, prostate cancer (PCa) is the most common non-cutaneous cancer in men. Human and canine prostate glands share many functional, anatomical and physiological features. Due to these similarities, canine PCa has been proposed as a model for PCa in men. PCa is typically androgen-dependent at diagnosis in men and for this reason, androgen deprivation therapies (ADT) are important treatments for advanced PCa in men. In contrast, there is some evidence that PCa is diagnosed more commonly in castrate dogs, at which point, limited therapeutic options are available. In men, a major limitation of current ADT is that progression to a lethal and incurable form of PCa, termed castrate-resistant prostate cancer (CRPC), is common. There is, therefore, an urgent need for a better understanding of the mechanism of PCa initiation and progression to CRPC to enable the development of novel therapeutic approaches. This review focuses on the functional, physiological, endocrine and histopathological similarities and differences in the prostate gland of these species. In particular, we focus on common physiological roles for androgen signalling in the prostate of men and dogs, we review the short- and longer-term effects of castration on PCa incidence and progression in the dog and relate how this knowledge may be relevant to understanding the mechanisms of CRPC in men.

A novel urinary mRNA signature using the droplet digital polymerase chain reaction platform improves discrimination between prostate cancer and benign prostatic hyperplasia within the prostate-specific antigen gray zone

Purpose

The aim of this study was to identify a noninvasive urinary marker for prostate cancer (PCa) diagnosis and to validate the clinical performance of this novel urinary mRNA signature using the droplet digital polymerase chain reaction (ddPCR) approach.

Materials and Methods

A gene expression microarray (HT-12, Illumina Inc., USA) was used to identify genes differentially expressed between 16 PCa and 8 benign prostatic hyperplasia (BPH) tissues; ddPCR (QX200; Bio-Rad Laboratories, USA) was carried out to quantify the expression of selected genes in urine. The urinary molecular PCa risk score (UMPCaRS) was calculated by using the sum of three upregulated genes as the numerator and the sum of three downregulated genes as the denominator. The diagnostic utility of the UMPCaRS was validated by using a screening set (10 PCa and 10 BPH samples) and a validation set (131 PCa and 105 BPH samples).

Results

Three upregulated genes (PDLIM5, GDF-15, THBS4) and three downregulated genes (UPK1A, SSTR3, NPFFR2) were selected from the microarray and subjected to ddPCR. The UMPCaRS for PCa in the screening and validation sets was significantly higher than that for BPH. For the validation set, the diagnostic accuracy of the UMPCaRS was comparable with that of prostate-specific antigen (PSA). Importantly, in the "PSA gray zone" (3-10 ng/mL), the AUC for the UMPCaRS was 0.843 and that for PSA was 0.628 (p<0.001).

Conclusions

The data demonstrate that the UMPCaRS is useful for discriminating between PCa and BPH in the "PSA gray zone".

The relationship between homeobox B7 expression and the clinical characteristics of patient with prostate cancer

BACKGROUND

The prognosis of patients with prostate cancer (PCa) remains poor.

METHODS

GSE16560, GSE32448, GSE79957, GSE17951, and TCGA-PRAD were reanalyzed to evaluate the expression of homeobox B7 (HOXB7) between PCa tissues and normal prostate tissues and to characterize the correlation between the expression of HOXB7 and the clinicopathological features of patients with PCa. Gene set enrichment analysis was conducted to investigate the mechanisms.

RESULTS

HOXB7 was upregulated in PCa tissues (P = 0.0005). Both the univariate and multivariate analyses demonstrated that the expression of HOXB7 was correlated with the Gleason score and TNM staging of patients with PCa. The Gleason score and TNM staging were higher in the HOXB7 high expression group. The overall survival (hazard ratio [HR] = 0.632; 95% confidence interval [CI]: 0.4773-0.8369; P = 0.0014) and progression-free survival (HR = 0.544; 95% CI: 0.3157-0.9373; P = 0.0283) favored patients with PCa in HOXB7 low expression group over those in HOXB7 high expression group. PCa samples in HOXB7 low expression group were enriched in gene sets associated with the epithelial mesenchymal transition, apical junction, angiogenesis, ultraviolet response, and hypoxia.

CONCLUSIONS

HOXB7 might be an independent prognostic factor of patients with PCa.

A decision analysis comparing 3 active surveillance protocols for the treatment of patients with low-risk prostate cancer

BACKGROUND

Active surveillance (AS) is a viable management option for approximately 50% of men who are newly diagnosed with prostate cancer. To the authors' knowledge, no direct comparisons between the different variants of AS protocols have been conducted to date. The authors developed a microsimulation decision model to evaluate which of 3 alternative AS protocols is optimal for men with low-risk prostate cancer, and compared each of these with immediate treatment.

METHODS

Men who were diagnosed with low-risk prostate cancer at age 65 years were modeled as having been treated with either immediate therapy or via each of 3 AS protocols. Modeled AS protocols represent those in the literature; a modified AS protocol was included in a sensitivity analysis. Immediate therapy included radical prostatectomy, external-beam radiotherapy, or brachytherapy. Outcome measures were quality-adjusted life-years (QALYs) and costs. Cost-effectiveness analysis and deterministic and probabilistic sensitivity analyses were performed.

RESULTS

Immediate therapy produced fewer QALYs than all variants of AS. Of the AS protocols evaluated, biennial biopsy was found to be the only efficient option, with an incremental cost-effectiveness ratio of $3490 per QALY compared with immediate therapy. It delayed the need for curative therapy by a mean of 56 months, and was found to be preferred in >86.9% of cases in probabilistic sensitivity analysis. A modified version of low-intensity AS dominated all other options.

CONCLUSIONS

For a 65-year-old man with low-risk prostate cancer, AS with biennial biopsy appears to be highly cost-effective compared with common alternatives. An AS protocol using triennial biopsy was found to dominate all other strategies and should be considered for men who are comfortable with a longer period between biopsies. The optimal strategy depends on a patient's tolerance for periodic biopsies and comfort with delaying radical treatment. Physicians should incorporate these patient preferences into decision making.

The Quality of Life among Men Receiving Active Surveillance for Prostate Cancer: An Integrative Review

Prostate cancer is very common among men in the United States. The current literature on active surveillance (AS) suggests that it is a promising treatment option for men with low-risk prostate cancer. The purpose of this manuscript is to provide a thorough integrative review regarding the effects of AS on the quality of life (QoL) of men with prostate cancer. Utilizing a methodological strategy, electronic databases were reviewed for empirical articles during the time frame of January 2006 to December 2016. A total of 37 articles met the inclusion criteria wherein 20 focused on the QoL among men only receiving AS and 16 reported QoL among men undergoing AS and other forms of treatment for prostate cancer. The review highlights the purpose, common instruments, race and ethnicity, and strengths and limitations of each article. The majority of articles indicated low levels of anxiety and depression and decreased incidences of bladder, bowel and sexual functioning among men undergoing AS in comparison to men who received other treatment modalities. The results indicated that additional research is needed to determine the QoL among men receiving AS on a longitudinal basis. The results support previous literature that indicated the positive impact of AS on low-risk prostate cancer.

Characterization of prostate microstructure using water diffusion and NMR relaxation

For many pathologies, early structural tissue changes occur at the cellular level, on the scale of micrometers or tens of micrometers. Magnetic resonance imaging (MRI) is a powerful non-invasive imaging tool used for medical diagnosis, but its clinical hardware is incapable of reaching the cellular length scale directly. In spite of this limitation, microscopic tissue changes in pathology can potentially be captured indirectly, from macroscopic imaging characteristics, by studying water diffusion. Here we focus on water diffusion and NMR relaxation in the human prostate, a highly heterogeneous organ at the cellular level. We present a physical picture of water diffusion and NMR relaxation in the prostate tissue, that is comprised of a densely-packed cellular compartment (composed of stroma and epithelium), and a luminal compartment with almost unrestricted water diffusion. Transverse NMR relaxation is used to identify fast and slow T ₂ components, corresponding to these tissue compartments, and to disentangle the luminal and cellular compartment contributions to the temporal evolution of the overall water diffusion coefficient. Diffusion in the luminal compartment falls into the short-time surface-to-volume (S/V) limit, indicating that only a small fraction of water molecules has time to encounter the luminal walls of healthy tissue; from the S/V ratio, the average lumen diameter averaged over three young healthy subjects is measured to be 217.7±188.7 μm. Conversely, the diffusion in the cellular compartment is highly restricted and anisotropic, consistent with the fibrous character of the stromal tissue. Diffusion transverse to these fibers is well described by the random permeable barrier model (RPBM), as confirmed by the dynamical exponent ϑ = 1/2 for approaching the long-time limit of diffusion, and the corresponding structural exponent p = -1 in histology. The RPBM-derived fiber diameter and membrane permeability were 19.8±8.1 μm and 0.044±0.045 μm/ms, respectively, in agreement with known values from tissue histology and membrane biophysics. Lastly, we revisited 38 prostate cancer cases from a recently published study, and found the same dynamical exponent ϑ = 1/2 of diffusion in tumors and benign regions. Our results suggest that a multi-parametric MRI acquisition combined with biophysical modeling may be a powerful non-invasive complement to prostate cancer grading, potentially foregoing biopsies.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

Are magnetic resonance imaging undetectable prostate tumours clinically significant? Results of histopathological analyses

OBJECTIVE

To investigate whether tumours at threshold values for detection on magnetic resonance imaging (MRI) represent clinically significant tumours or not, and therefore the utility of MRI in active surveillance (AS) protocols.

PATIENTS AND METHODS

A retrospective analysis of a single institution database was performed after Institutional Review Board approval. Between 2010 and 2013, 1633 patients underwent robot-assisted laparoscopic prostatectomy (RALP) at a single institution by a single surgeon. Of these, 1361 had complete clinical data and were included in analysis. Multivariate logistic regression was used to assess histopathological grade compared to tumour size whilst controlling for biopsy Gleason score, prostate-specific antigen level, body mass index, race, and age.

RESULTS

Of 120 tumours <5 mm in size, four were Gleason score 4 + 3. Of 276 tumours of 5-10 mm, 22 (8.1%) were Gleason score 4 + 3 and one (0.2%) was Gleason score 8. On multivariate regression analyses, tumours of <5 mm were much less likely to be high grade (Gleason score >3 + 4) at RALP compared to larger tumours (3.3% vs 25.1%, P < 0.001), or Gleason score ⩾8 (0.0% vs 7.6%, P < 0.001). Size was further shown to significantly correlate with grade on multivariate regression (P < 0.001).

CONCLUSIONS

Prostate tumours below the detection threshold for MRI (5 mm) most probably represent clinically insignificant tumours, which alone would not necessitate leaving AS in favour of more aggressive therapy. These findings point to a possible role of MRI in modern AS protocols.

Variation in Guideline Concordant Active Surveillance Followup in Diverse Urology Practices

PURPOSE

We examined the frequency of followup prostate specific antigen testing and prostate biopsy among men treated with active surveillance in the academic and community urology practices comprising MUSIC (Michigan Urological Surgery Improvement Collaborative).

MATERIALS AND METHODS

MUSIC is a consortium of 42 practices that maintains a prospective clinical registry with validated clinical data on all patients diagnosed with prostate cancer at participating sites. We identified all patients in MUSIC practices who entered active surveillance and had at least 2 years of continuous followup. After determining the frequency of repeat prostate specific antigen testing and prostate biopsy, we calculated rates of concordance with NCCN Guidelines® recommendations (ie at least 3 prostate specific antigen tests and 1 surveillance biopsy) collaborative-wide and across individual practices.

RESULTS

We identified 513 patients who entered active surveillance from January 2012 through September 2013 and had at least 2 years of followup. Among the 431 men (84%) who remained on active surveillance for 2 years 132 (30.6%) underwent followup surveillance testing at a frequency that was concordant with NCCN® (National Comprehensive Cancer Network®) recommendations. At the practice level, the median rate of guideline concordant followup was 26.5% (range 10% to 67.5%, p <0.001). Among patients with discordant followup, the absence of followup biopsy was common and not significantly different across practices (median rate 82.0%, p = 0.35).

CONCLUSIONS

Among diverse community and academic practices in Michigan, there is wide variation in the proportion of men on active surveillance who meet guideline recommendations for followup prostate specific antigen testing and repeat biopsy. These data highlight the need for standardized active surveillance pathways that emphasize the role of repeat surveillance biopsies.

Discontinuous unilateral involvement of 12 part core biopsies by adenocarcinoma predicts bilateral involvement of subsequent radical prostatectomy

At our institution, percent tumor burden in prostate core biopsies is quantified using variations of one of two methods. Measurement by the Aggregate method reports only adenocarcinoma and omits intervening stroma and benign prostatic glands while the Discontinuous method includes the intervening stroma and benign glands between distinct foci of adenocarcinoma. In this study, we selected cases with 12-part core biopsies that were followed by a radical prostatectomy within two years. Interestingly, we found that when adenocarcinoma involved prostate 12-part core biopsies and subsequent resection unilaterally, there is no significant difference in absolute percentage of tumor using either measuring method (P = 0.4). In contrast, when adenocarcinoma involved the biopsies unilaterally and subsequent prostatectomy bilaterally, the two measurement methods had a statistically significant difference in percentage scores (P = 0.002). In the study cohort, other factors including Gleason score (P = 0.88) and total number of adenocarcinoma-involved cores (P = 0.27) did not introduce any significant correlation with bilateral involvement. In this study, we found that biopsies that discontinuously and unilaterally involve half of a prostate are much more likely to involve both lobes than those that are unilateral and present in nodular aggregates.

Hemiablative Focal Low Dose Rate Brachytherapy: A Phase II Trial Protocol

BACKGROUND

The objective of focal brachytherapy (BT) is to provide effective prostate cancer control for low-risk disease but with reduced genitourinary, gastrointestinal and sexual side effects in a cost-effective way.

OBJECTIVE

The aim of this study is to describe a phase II study examining technical and dosimetric feasibility and toxicity, quality of life changes, and local control with post-treatment biopsy outcomes in men with early stage low volume prostate cancer treated with focal iodine-125 seed BT.

METHODS

The study design is a prospective, multicenter trial with a planned sample size of 20 patients including men with a minimum age of 60 years, a life expectancy estimated to be greater than 10 years, with low or low-tier intermediate risk prostate cancer, unilateral disease on the biopsy, and a Gleason score of ≤3+4 and <25% cores involved. The investigations specific for the study are multi-parametric magnetic resonance imaging (Mp-MRI) baseline, at 20 and 36 months to rule out high grade disease and a transperineal mapping biopsy (baseline and at 36 months) for more accurate patient selection. The hemigland region will receive 144 Gy. Standard normal tissue constraints will be considered as for a whole gland (WG) implant. Dosimetric parameters will be evaluated at day 30 after the implant. Toxicity and quality of life will be evaluated with international validated questionnaires focusing on urinary, rectal, sexual domain, and general health-related quality of life. The patients will complete this assessment at baseline and then approximately every 6 months after the implant up to 10 years.

RESULTS

To date, one patient is involved in the trial. He underwent the pre-implant investigations which found bilateral disease. Therefore, a standard seed implant was performed. If the results from this trial provide evidence that the treatment is safe, feasible, and improves toxicity, funding will be sought to conduct a large, multicenter, randomized controlled trial (RCT).

CONCLUSIONS

This protocol is designed to show feasibility in delivering hemigland focal therapy with seed BT. It may answer crucial questions and obtain data which will enable downstream decisions on focal low dose rate (LDR) prostate BT.

CLINICALTRIAL

Clinicaltrial.gov NCT02643511; https://www.clinicaltrials.gov/ct2/show/NCT02643511 (Archived by Webcite at http://www.webcitation.org/6ghLCzIhY).

Current status of active surveillance in prostate cancer

Active surveillance (AS) is a management strategy involving close monitoring the course of disease with the expectation to intervene if the cancer progress, in a super-selected group of low-risk prostate cancer (PCa) patients. Determining AS candidates should be based on careful individualized weighing of numerous factors: life expectancy, general health condition, disease characteristics, potential side effects of treatment, and patient preference. Several protocols have been developed to determine insignificant PCa for choosing ideal AS candidates. Results regarding disease reclassification during AS have been also reported. In an effort to enhance accuracy during selection of AS candidate, there were several reports on using magnetic resonance imaging for prediction of insignificant PCa. Currently, there is an urgent need for further clinical studies regarding the criteria for recommending AS, the criteria for reclassification on AS, and the schedule for AS. Considering the racial differences in behavior of PCa between Western and Asian populations, more stringent AS protocols for Asian patients should be established from additional, well-designed, large clinical studies.

A Novel Quantitative Multiplex Tissue Immunoblotting for Biomarkers Predicts a Prostate Cancer Aggressive Phenotype

BACKGROUND

Early prediction of disease progression in men with very low-risk (VLR) prostate cancer who selected active surveillance (AS) rather than immediate treatment could reduce morbidity associated with overtreatment.

METHODS

We evaluated the association of six biomarkers [Periostin, (-5, -7) proPSA, CACNA1D, HER2/neu, EZH2, and Ki-67] with different Gleason scores and biochemical recurrence (BCR) on prostate cancer TMAs of 80 radical prostatectomy (RP) cases. Multiplex tissue immunoblotting (MTI) was used to assess these biomarkers in cancer and adjacent benign areas of 5 μm sections. Multivariate logistic regression (MLR) was applied to model our results.

RESULTS

In the RP cases, CACNA1D, HER2/neu, and Periostin expression were significantly correlated with aggressive phenotype in cancer areas. An MLR model in the cancer area yielded a ROC-AUC = 0.98, whereas in cancer-adjacent benign areas, yielded a ROC-AUC = 0.94. CACNA1D and HER2/neu expression combined with Gleason score in a MLR model yielded a ROC-AUC = 0.79 for BCR prediction. In the small biopsies from an AS cohort of 61 VLR cases, an MLR model for prediction of progressors at diagnosis retained (-5, -7) proPSA and CACNA1D, yielding a ROC-AUC of 0.78, which was improved to 0.82 after adding tPSA into the model.

CONCLUSIONS

The molecular profile of biomarkers is capable of accurately predicting aggressive prostate cancer on retrospective RP cases and identifying potential aggressive prostate cancer requiring immediate treatment on the AS diagnostic biopsy but limited in BCR prediction.

IMPACT

Comprehensive profiling of biomarkers using MTI predicts prostate cancer aggressive phenotype in RP and AS biopsies.

TOOKAD® Soluble focal therapy: pooled analysis of three phase II studies assessing the minimally invasive ablation of localized prostate cancer

PURPOSE

To evaluate the 6-month effects of the recommended drug and light dosage in focal vascular-targeted photodynamic therapy (VTP) using TOOKAD(®) Soluble in patients with localized prostate cancer (LPCa).

METHODS

We performed a pooled analysis of 117 men with LPCa, PSA <10 ng/mL, and Gleason score ≤ 7 (3 + 4), from 3 studies who received a 10-min intravenous infusion of a single dose of 4 mg/kg TOOKAD(®) Soluble, activated by a 753-nm light at 200 J/cm delivered in the prostate by transperineal fibres under transrectal ultrasound guidance. Primary endpoint was 6-month negative biopsies in the treated lobe(s). PSA was measured at month 1, 3, and 6. Magnetic resonance imaging was performed at day 7, month 3, and 6. International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF-5) and adverse events were reported at day 7, month 1, 3, and 6.

RESULTS

Month 6 negative biopsy rate was 68.4 % in the overall evaluable population (N = 114) and 80.6 % for patients treated by hemiablation with light density index (LDI) ≥ 1 (N = 67). Mean prostate necroses at week-1 were 76.5 and 86.3 %, respectively. In both groups, PSA levels at month 6 decreased by 2.0 ng/mL. Small changes from baseline for IPSS and IIEF-5 indicated a slight improvement in urinary function and a slight deterioration in sexual function.

CONCLUSIONS

Focal VTP treatment with TOOKAD(®) Soluble at 4 mg/kg and 200 J/cm resulted in a negative 6-month biopsy rate of 68.4 % for the whole population and 80.6 % for patients treated by hemiablation with LDI ≥ 1. The treatment was well tolerated. Two phase III studies will reach completion in early 2015.

Determination of optimal drug dose and light dose index to achieve minimally invasive focal ablation of localised prostate cancer using WST11-vascular-targeted photodynamic (VTP) therapy

OBJECTIVE

To determine the optimal drug and light dose for prostate ablation using WST11 (TOOKAD Soluble) for vascular-targeted photodynamic (VTP) therapy in men with low-risk prostate cancer.

PATIENTS AND METHODS

In all, 42 men with low-risk prostate cancer were enrolled in the study but two who underwent anaesthesia for the procedure did not receive the drug or light dose. Thus, 40 men received a single dose of 2, 4 or 6 mg/kg WST11 activated by 200 J/cm light at 753 nm. WST11 was given as a 10-min intravenous infusion. The light dose was delivered using cylindrical diffusing fibres within hollow plastic needles positioned in the prostate using transrectal ultrasonography (TRUS) guidance and a brachytherapy template. Magnetic resonance imaging (MRI) was used to assess treatment effect at 7 days, with assessment of urinary function (International Prostate Symptom Score [IPSS]), sexual function (International Index of Erectile Function [IIEF]) and adverse events at 7 days, 1, 3 and 6 months after VTP. TRUS-guided biopsies were taken at 6 months.

RESULTS

In all, 39 of the 40 treated men completed the follow-up. The Day-7 MRI showed maximal treatment effect (95% of the planned treatment volume) in men who had a WST11 dose of 4 mg/kg, light dose of 200 J/cm and light density index (LDI) of >1. In the 12 men treated with these parameters, the negative biopsy rate was 10/12 (83%) at 6 months, compared with 10/26 (45%) for the men who had either a different drug dose (10 men) or an LDI of <1 (16). Transient urinary symptoms were seen in most of the men, with no significant difference in IPSS score between baseline and 6 months after VTP. IIEF scores were not significantly different between baseline and 6 months after VTP.

CONCLUSION

Treatment with 4 mg/kg TOOKAD Soluble activated by 753 nm light at a dose of 200 J/cm and an LDI of >1 resulted in treatment effect in 95% of the planned treatment volume and a negative biopsy rate at 6 months of 10/12 men (83%).

Clinical perspectives: practical insights from clinical experience with cabazitaxel in Australia

Prostate cancer, and in particular the management options for patients with metastatic castration-resistant prostate cancer (mCRPC), remains an important health issue. The approval of cabazitaxel provides a new treatment option for patients who have progressed despite docetaxel therapy. Clinical use of cabazitaxel in mCRPC is based on the results of the TROPIC study, which demonstrated an approximately 30% reduction in the risk of death compared with mitoxantrone. In this paper, we draw on accumulating clinical experience with cabazitaxel in Australia to discuss important questions such as how to select the right patient for treatment and how to proactively prevent and manage toxicities associated with this therapy. Recognizing the need for a multidisciplinary approach to patient care, opinion and insight has been sought from medical oncologists, nurses and pharmacists. While lack of trial data means that a number of questions remain unanswered, local clinical experience has helped to guide treatment decisions and refine management protocols. Appropriate patient selection, careful ongoing monitoring and proactive management of adverse events will ensure optimal treatment of patients. Nurses in particular play an important role in educating patients and identifying patients at increased risk of developing adverse events with cabazitaxel. The oncology team must work together to educate patients; taking a proactive approach to issues such as adverse events will help maximize the clinical outcome of cabazitaxel treatment and impact positively on the patient's quality of life.

On the relationship between tumor structure and complexity of the spatial distribution of cancer cell nuclei: a fractal geometrical model of prostate carcinoma

BACKGROUND

A risk of the prostate cancer patient is defined by both the objective and subjective criteria, that is, PSA concentration, Gleason score, and pTNM-stage. The subjectivity of tumor grading influences the risk assessment owing to a large inter- and intra-observer variability. Pathologists propose a central prostate pathology review as a remedy for this problem; yet, the review cannot eliminate the subjectivity from the diagnostic algorithm. The spatial distribution of cancer cell nuclei changes during tumor progression. It implies changes in complexity measured by the capacity dimension D0, the information dimension D1, and the correlation dimension D2.

METHODS

The cornerstone of the approach is a model of prostate carcinomas composed of the circular fractals CF(4), CF(6 + 0), and CF(6 + 1). This model is both geometrical and analytical, that is, its structure is well-defined, the capacity fractal dimension D0 can be calculated for the infinite circular fractals, and the dimensions D0, D1, D2 can be computed for their finite counterparts representing distribution of cell nuclei. The model enabled both the calibration of the software and the validation of the measurements in 124 prostate carcinomas. The ROC analysis defined the cut-off D0 values for seven classes of complexity.

RESULTS

The Gleason classification matched in part with the classification based on the D0 values. The mean ROC sensitivity was 81.3% and the mean ROC specificity 75.2%. Prostate carcinomas were re-stratified into seven classes of complexity according to their D0 values. This increased both the mean ROC sensitivity and the mean ROC specificity to 100%. All homogeneous Gleason patterns were subordinated to the class C1, C4, or C7. D0 = 1.5820 was the cut-off D0 value between the complexity class C2 and C3 representing low-risk cancers and intermediate-risk cancers, respectively.

CONCLUSIONS

The global fractal dimensions eliminate the subjectivity in the diagnostic algorithm of prostate cancer. Those complexity measures enable the objective subordination of carcinomas to the well-defined complexity classes, and define subgroups of carcinomas with very low malignant potential (complexity class C1) or at a large risk of progression (complexity ass C7).

Diffusion-weighted magnetic resonance imaging for prediction of insignificant prostate cancer in potential candidates for active surveillance

OBJECTIVES

To investigate whether the apparent diffusion coefficient (ADC) from diffusion-weighted magnetic resonance imaging (DW-MRI) could help improve the prediction of insignificant prostate cancer in candidates for active surveillance (AS).

METHODS

Enrolled in this retrospective study were 287 AS candidates who underwent DW-MRI before radical prostatectomy. Patients were stratified into two groups; Group A consisted of patients with no visible tumour or a suspected tumour ADC value > 0.830 × 10(-3) mm(2)/sec and Group B consisted of patients with a suspected tumour ADC value < 0.830 × 10(-3) mm(2)/sec. We compared pathological outcomes in each group.

RESULTS

Group A had 243 (84.7 %) patients and Group B had 44 (15.3 %) patients. The proportion of organ-confined Gleason ≤ 6 disease and insignificant prostate cancer was significantly higher in Group A than Group B (61.3 % vs. 38.6 %, p = 0.005 and 47.7 % vs. 25.0 %, p = 0.005, respectively). On multivariate analysis, a high ADC value was the independent predictor of organ-confined Gleason ≤ 6 disease and insignificant prostate cancer (odds ratio = 2.43, p = 0.011 and odds ratio = 2.74, p = 0.009, respectively).

CONCLUSION

Tumour ADC values may be a useful marker for predicting insignificant prostate cancer in candidates for AS.

KEY POINTS

• ADC from DW-MRI can help assess prostate cancer aggressiveness in potential AS candidates. • There was a closed correlation between higher ADC values and insignificant prostate cancer. • The absence of lesions on DWI/DWI can help select potential AS candidates.

Imaging modalities in focal therapy: patient selection, treatment guidance, and follow-up

PURPOSE OF REVIEW

Focal therapy for prostate cancer is emerging as a management option between active surveillance and radical treatments. In this article, we present two of the most important imaging modalities in focal therapy, multiparametric MRI (mpMRI) and ultrasonography. We review the recent advances within these two platforms.

RECENT FINDINGS

State-of-the-art imaging in all phases of focal therapy is essential for treatment safety. In patient selection, treatment guidance, and follow-up, different aspects of imaging are important. mpMRI is an imaging technology with high imaging resolution and contrast. This makes it an excellent technology for patient selection and treatment planning and follow-up. Ultrasound has the unique property of real-time image acquisition. This makes it an excellent technology for real-time treatment guidance. There are multiple novelties in these two platforms that have increased the accuracy considerably. Examples in ultrasound are contrast-enhanced ultrasonography, elastography, shear-wave elastography, and histoscanning. In mpMRI, these advantages consist of multiple sequences combined to one image and magnetic resonance thermometry.

SUMMARY

Standardization of multiparametric transrectal ultrasound and mpMRI is of paramount importance. For targeted treatment and follow-up, a good negative predictive value of the test is important. There is much to gain from both of these developing fields and imaging accuracy of the two platforms is comparable. Standardization in conduct and interpretation, three-dimensional reconstruction, and fusion of the two platforms can make focal therapy the standard of care for prostate cancer.

miR-19, miR-345, miR-519c-5p serum levels predict adverse pathology in prostate cancer patients eligible for active surveillance

Serum microRNAs hold great promise as easily accessible and measurable biomarkers of disease. In prostate cancer, serum miRNA signatures have been associated with the presence of disease as well as correlated with previously validated risk models. However, it is unclear whether miRNAs can provide independent prognostic information beyond current risk models. Here, we focus on a group of low-risk prostate cancer patients who were eligible for active surveillance, but chose surgery. A major criteria for the low risk category is a Gleason score of 6 or lower based on pre-surgical biopsy. However, a third of these patients are upgraded to Gleason 7 on post surgical pathological analysis. Both in a discovery and a validation cohort, we find that pre-surgical serum levels of miR-19, miR-345 and miR-519c-5p can help identify these patients independent of their pre-surgical age, PSA, stage, and percent biopsy involvement. A combination of the three miRNAs increased the area under a receiver operator characteristics curve from 0.77 to 0.94 (p<0.01). Also, when combined with the CAPRA risk model the miRNA signature significantly enhanced prediction of patients with Gleason 7 disease. In-situ hybridizations of matching tumors showed miR-19 upregulation in transformed versus normal-appearing tumor epithelial, but independent of tumor grade suggesting an alternative source for the increase in serum miR-19a/b levels or the release of pre-existing intracellular miR-19a/b upon progression. Together, these data show that serum miRNAs can predict relatively small steps in tumor progression improving the capacity to predict disease risk and, therefore, potentially drive clinical decisions in prostate cancer patients. It will be important to validate these findings in a larger multi-institutional study as well as with independent methodologies.

Is there a role for anterior zone sampling as part of saturation trans-rectal ultrasound guided prostate biopsy?

Background

The prostatic anterior zone (AZ) is not targeted routinely by TRUS guided prostate biopsy (TRUS-Pbx). MRI is an accurate diagnostic tool for AZ tumors, but is often unavailable due to cost or system restrictions. We examined the diagnostic yield of office based AZ TRUS-Pbx.

Methods

127 men at risk for AZ tumors were studied: Patients with elevated PSA and previous extended negative TRUS-Pbx (group 1, n = 78) and actively surveyed low risk prostate cancer patients (group 2, n = 49). None of the participants had a previous AZ biopsy. Biopsy template included suspicious ultrasonic areas, 16 peripheral zone (PZ), 4 transitional zone (TZ) and 6 AZ cores. All biopsies were performed by a single urologist under local peri-prostatic anaesthetic, using the B-K Medical US System, an end-firing probe 4-12 MHZ and 18 ga/25 cm needle. All samples were reviewed by a single specialized uro-pathologist. Multivariate analysis was used to detect predictors for AZ tumors accounting for age, PSA, PSA density, prostate volume, BMI, and number of previous biopsies.

Results

Median PSA was 10.4 (group 1) and 7.3 (group 2). Age (63.9, 64.5), number of previous biopsies (1.5) and cores (17.8, 21.3) and prostate volume (56.4 cc, 51 cc) were similar for both groups. The overall diagnostic yield was 34.6% (group 1) and 85.7% (group 2). AZ cancers were detected in 21.8% (group 1) and 34.7% (group 2) but were rarely the only zone involved (1.3% and 4.1% respectively). Gleason ≥ 7 AZ cancers were often accompanied by equal grade PZ tumors. In multivariate analysis only prostate volume predicted for AZ tumors. Patients detected with AZ tumors had significantly smaller prostates (36.9 cc vs. 61.1 cc p < 0.001). Suspicious AZ ultrasonic findings were uncommon (6.3%).

Conclusions

TRUS-Pbx AZ sampling rarely improves the diagnostic yield of extended PZ sampling in patients with elevated PSA and previous negative biopsies. In low risk prostate cancer patients who are followed by active surveillance, AZ sampling changes risk stratification in 6% but larger studies are needed to define the role of AZ sampling in this population and its correlation with prostatectomy final pathological specimens.

Imaging and Markers as Novel Diagnostic Tools in Detecting Insignificant Prostate Cancer: A Critical Overview

Recent therapeutic advances for managing low-risk prostate cancer include the active surveillance and focal treatment. However, locating a tumor and detecting its volume by adequate sampling is still problematic. Development of predictive biomarkers guiding individual therapeutic choices remains an ongoing challenge. At the same time, prostate cancer magnetic resonance imaging is gaining increasing importance for prostate diagnostics. The high morphological resolution of T2-weighted imaging and functional MRI methods may increase the specificity and sensitivity of diagnostics. Also, recent studies founded an ability of novel biomarkers to identify clinically insignificant prostate cancer, risk of progression, and association with poor differentiation and, therefore, with clinical significance. Probably, the above mentioned methods would improve tumor characterization in terms of its volume, aggressiveness, and focality. In this review, we attempted to evaluate the applications of novel imaging techniques and biomarkers in assessing the significance of the prostate cancer.

Prostate cancer and the increasing role of active surveillance

Prostate cancer (PC) is the most often diagnosed non-skin cancer and the second leading cause of cancer-related death among men in the United States. As a result, for many years the American Urological Association (AUA) and the American Cancer Society have issued statements recommending screening for PC, resulting in its widespread implementation in the United States. Recently, the United States Preventative Services Task Force gave PC screening a recommendation of D, that is, against PC screening for all men. The AUA countered this recommendation, stating that since the development of PC screening using prostate-specific antigen, a reduction in PC-specific mortality has been seen, and that the risk reduction occurred in a setting in which many of the patients were not aggressively treated for prostate cancer. Active surveillance may be described as a method to potentially delay or obviate the need for treatment in men with clinically insignificant PC or PC thought to be at low risk for progression. Studies have shown no significant difference in outcome or pathology between men with low risk PC who receive treatment at the point of progression and those undergoing immediate treatment. Ongoing studies are evaluating the efficacy and utility of active surveillance for low-risk PC. Interim results of these studies have shown that approximately 30% of patients progress on active surveillance. However, "progression" does not necessarily mean treatment failure; rarely do patients develop locally advanced or metastatic disease. Active surveillance has also been shown to be cost-effective when compared with immediate treatment for PC. Longer follow-up may continue to show an increased benefit of active surveillance as a reasonable initial approach to the management of men with low-risk, clinically localized PC.

TOOKAD(®) Soluble vascular-targeted photodynamic (VTP) therapy: determination of optimal treatment conditions and assessment of effects in patients with localised prostate cancer

OBJECTIVES

To evaluate the optimal treatment conditions and effects of TOOKAD(®) Soluble vascular-targeted photodynamic (VTP) therapy in patients with localised prostate cancer. To evaluate the safety and quality of life after TOOKAD(®) Soluble VTP treatment in patients with localised prostate cancer.

PATIENTS AND METHODS

Men (aged >18 years) diagnosed with localised prostate cancer, who were suitable for active surveillance, were invited to take part in the study. Patients who had received prior or current treatment for their cancer were excluded. There were two parts to the study: in part one, patients were assigned to one of two treatment groups based on the size of their prostates (patients with prostate size <60 mL would receive 4 mg/kg TOOKAD(®) Soluble and patients with prostate size ≥60 mL would receive 6 mg/kg TOOKAD(®) Soluble both activated with 200 J/cm light). In part two, patients were assigned to one of two treatment groups based on predefined criteria and received either 4 or 6 mg/kg TOOKAD(®) Soluble and 200 or 300 J/cm light. VTP was conducted under general anaesthesia using TOOKAD(®) Soluble administered intravenously and activated by light-diffusing fibres within the prostate via the perineum. Follow-up was conducted for 6 months. Magnetic resonance imaging (MRI) carried out at 1 week after VTP and transrectal prostate biopsy at 6 months were the key endpoints. Adverse event (AE) recording and patient-reported outcome measures were collected.

RESULTS

In all, 86 patients were enrolled in the study and 85 patients received treatment. Of the 85 treated patients, one patient discontinued (due to withdrawal of consent). At 6 months, 61/83 (74%) patients who underwent prostate biopsy had histopathology that was negative for prostate cancer (95% confidence interval (CI) 62.7-82.6%). Considering patients who received 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light (unilateral), which are considered optimal treatment parameters, 38/46 (83%) patients had histopathology from the biopsies that was negative for prostate cancer at 6 months (95% CI 68.6-92.2%; P < 0.001). The mean percentage of necrosis of the targeted prostate tissue at 7 days after VTP was 78% overall (83 patients) with extraprostatic necrosis reported in 76% (63/83) of patients. Considering patients who received 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light (unilateral), the mean 7-day necrosis percentage was 88% (46 patients) with extraprostatic necrosis reported in 72% (33/46) of patients. All occurrences of extraprostatic necrosis were considered clinically acceptable and none were associated with any clinical sequelae. The mean percentage prostate necrosis at 7 days was statistically significantly higher (P < 0.001) in patients treated with a therapeutic light density index (LDI) of ≥1 than those treated with a LDI of <1. The percentage of patients with negative biopsies at 6 months was also higher in patients treated with a therapeutic LDI of ≥1 than those treated with a LDI of <1 (78.6% and 63.0%, respectively). In all, 87% (75/86) of patients reported at least one treatment-emergent AE during the study. Most AEs were mild or moderate in intensity and considered related to the technical procedures of the study. No treated patients had hypotension or discontinued due to AEs. Eight patients (9.3%) had serious AEs; none resulted in discontinuation from the study.

CONCLUSIONS

Biopsy data, post-treatment dynamic contrast-enhancement MRI at 1 week after VTP and analysis of the safety data have shown that 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light are the optimal treatment conditions for the VTP procedure resulting in >80% of patients treated with this regimen having a negative biopsy at 6 months. Overall, the treatment was well tolerated and exhibited early signs of efficacy for minimally invasive focal treatment of localised prostate cancer.

Utility of diffusional kurtosis imaging as a marker of adverse pathologic outcomes among prostate cancer active surveillance candidates undergoing radical prostatectomy

OBJECTIVE

The purpose of this study was to compare findings at nongaussian diffusional kurtosis imaging and conventional diffusion-weighted MRI as markers of adverse pathologic outcomes among prostate cancer patients who are active surveillance candidates and choose to undergo prostatectomy.

MATERIALS AND METHODS

Fifty-eight active surveillance candidates (prostate-specific antigen concentration, < 10 ng/mL; clinical tumor category less than T2a; Gleason score, 3 + 3; ≤ 25% of biopsy cores positive for tumor; ≤ 50% tumor involvement of any individual core; ≤ 20% tumor involvement across all cores) who underwent prostatectomy and preoperative 3-T MRI including diffusional kurtosis imaging (b values, 0, 500, 1000, 1500, and 2000 s/mm(2)) were included. Adverse pathologic features at prostatectomy were defined using two schemes of varying stringency. One scheme (less stringent) was presence of a Gleason score greater than 6 or extracapsular extension (n = 19). The other scheme (more stringent) was presence of a Gleason score greater than 6, extracapsular extension, or an index tumor 10 mm or larger (n = 35). Parametric maps displaying standard apparent diffusion coefficient (ADC), kurtosis (K) representing nongaussian diffusion behavior, and diffusion (D) representing a diffusion coefficient adjusted for nongaussian (kurtosis) behavior were reviewed, and the most abnormal region was recorded for each metric. Associations between these metrics and the presence of adverse final pathologic findings were assessed with unpaired Student t tests and receiver operating characteristic analyses.

RESULTS

For both schemes, only D was significantly lower in patients with adverse final pathologic findings (p = 0.006, p = 0.025). K tended to be greater in patients with adverse final pathologic findings for the more stringent scheme (p = 0.072). ADC was not significantly different in the presence of adverse final pathologic findings for either scheme (p = 0.357, p = 0.383). With either scheme, D had a larger area under the receiver operating characteristics curve (AUC) for predicting adverse final pathologic results (AUC, 0.691 and 0.743) than did ADC (AUC, 0.569 and 0.655) or K (AUC, 0.617 and 0.714), but the difference was not significant (p = 0.183, p = 0.734).

CONCLUSION

Preliminary results suggest that diffusional kurtosis imaging findings may have more value than findings at conventional diffusion-weighted MRI as a marker of adverse final pathologic outcome among active surveillance candidates.

EAU guidelines on prostate cancer. part 1: screening, diagnosis, and local treatment with curative intent-update 2013

CONTEXT

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

OBJECTIVE

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

PATIENT SUMMARY

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

Presenting treatment options to men with clinically localized prostate cancer: the acceptability of active surveillance/monitoring

Presenting treatment options to men with localized prostate cancer is difficult because of the lack of definitive evidence and the range of treatment options available. Active surveillance and monitoring programs are now a recognized treatment option for men with low-risk localized prostate cancer, but many patients are not fully aware of the details of such programs, and most still opt for immediate radical (surgery or radiotherapy) treatment. The provision of high-quality information with decision aids has been shown to increase the acceptability of active surveillance/monitoring programs. This chapter outlines techniques for providing high-quality information about active surveillance/monitoring, based on the findings of a randomized controlled trial of treatments for localized prostate cancer. The ProtecT (Prostate testing for cancer and Treatment) trial has randomized over 1500 men between active monitoring, radical surgery, and radical radiotherapy by ensuring that information was tailored to men's existing knowledge and views. Care was taken with the content, order, and enthusiasm of the presentation of treatments by recruitment staff, and clinicians and other health professionals were supported to feel comfortable with being open about the uncertainties in the evidence and helped to rephrase terminology likely to be misinterpreted by patients. These techniques of information provision should be added to the use of decision aids to enable patients diagnosed with clinically localized prostate cancer in routine practice to reach well-informed and reasoned decisions about their treatment, including full consideration of active surveillance and monitoring programs.

Regional, provider, and economic factors associated with the choice of active surveillance in the treatment of men with localized prostate cancer

Data on initial treatment of 8232 cases of localized prostate cancer diagnosed in 2004 were obtained by medical record abstraction (including hospital and outpatient locations) from seven state cancer registries participating in the Centers for Disease Control and Prevention's Breast and Prostate Cancer Data Quality and Patterns of Care Study. Distinction was made between men receiving no therapy with no monitoring plan (no therapy/no plan [NT/NP]) and those receiving active surveillance (AS). Overall, 8.6% received NT/NP and 4.7% received AS. Older age at diagnosis, lower clinical risk group, and certain registry locations were significant predictors of use of both AS and NT/NP. AS was also related to having more severe comorbidities, whereas nonwhite race was predicted receiving NT/NP. Men receiving AS lived in areas with a higher number of urologists per 100 000 men than those receiving NT/NP. In summary, physician and clinical factors were stronger predictors of AS, whereas demographic and regional factors were related to receiving NT/NP. Physicians appear reluctant to recommend AS for younger patients with no comorbidities.

Metabolomic imaging of prostate cancer with magnetic resonance spectroscopy and mass spectrometry

Metabolomic imaging of prostate cancer (PCa) aims to improve in vivo imaging capability so that PCa tumors can be localized noninvasively to guide biopsy and evaluated for aggressiveness prior to prostatectomy, as well as to assess and monitor PCa growth in patients with asymptomatic PCa newly diagnosed by biopsy. Metabolomics studies global variations of metabolites with which malignancy conditions can be evaluated by profiling the entire measurable metabolome, instead of focusing only on certain metabolites or isolated metabolic pathways. At present, PCa metabolomics is mainly studied by magnetic resonance spectroscopy (MRS) and mass spectrometry (MS). With MRS imaging, the anatomic image, obtained from magnetic resonance imaging, is mapped with values of disease condition-specific metabolomic profiles calculated from MRS of each location. For example, imaging of removed whole prostates has demonstrated the ability of metabolomic profiles to differentiate cancerous foci from histologically benign regions. Additionally, MS metabolomic imaging of prostate biopsies has uncovered metabolomic expression patterns that could discriminate between PCa and benign tissue. Metabolomic imaging offers the potential to identify cancer lesions to guide prostate biopsy and evaluate PCa aggressiveness noninvasively in vivo, or ex vivo to increase the power of pathology analysis. Potentially, this imaging ability could be applied not only to PCa, but also to different tissues and organs to evaluate other human malignancies and metabolic diseases.

Many young men with prostate-specific antigen (PSA) screen-detected prostate cancers may be candidates for active surveillance

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Little is known as to the potential for over-treatment of young men diagnosed with prostate cancer. We show that for men aged ≤55 years with PSA screen-detected disease, 45% of the tumours are classified as very low risk and 85% of these have favourable pathology, yet most are actively treated. These findings raise the spectre of over-treatment for a group of men likely to be affected by treatment side-effects.

OBJECTIVE

To identify a population of young men (aged <55 years at diagnosis) with very-low-risk prostate cancer (stage cT1c, with prostate-specific antigen [PSA] density of <0.15 ng/mL/g, Gleason score ≤6, and ≤2 positive biopsy cores with <50% tumour involvement) that may be candidates for active surveillance (AS).

PATIENTS AND METHODS

We queried a Department of Defense tumour registry and hard-copy records for servicemen diagnosed with prostate cancer from 1987 to 2010. Statistical analyses were undertaken using Fisher's exact and chi-square testing.

RESULTS

From 1987-1991 and 2007-2010, PSA screen-detected tumours diagnosed in men aged ≤55 years rose >30-fold. Data for a subset of men (174) with PSA screen-detected cancer were evaluable for disease risk assessment. Of the 174 men with screen-detected disease, 81 (47%) had very-low-risk disease. Of that group, 96% (78/81) selected treatment and, of 57 men undergoing radical prostatectomy (RP), the tumours of 49 (86%) carried favourable pathology (organ confined, <10% gland involvement, Gleason ≤6).

CONCLUSIONS

Nearly half of young men with PSA screen-detected prostate cancer are AS candidates but the overwhelming majority seek treatment. Considering that many tumours show favourable pathology at RP, there is a possibility that these patients may benefit from AS management.

A panel of five circulating microRNAs as potential biomarkers for prostate cancer

BACKGROUND

Circulating microRNA (miRNAs) have been shown to have the potential as noninvasive diagnosis markers in several types of cancers. In this study, we investigated whether circulating miRNAs could be used in the diagnosis of prostate cancer (CaP) in a Chinese patient population.

METHODS

Illumina's Human v2 miRNA microarray was used to analyze miRNAs levels in a small set of patients [25 CaP, 17 benign prostatic hyperplasia (BPH)] in an effort to identify CaP-specific miRNAs. The identified miRNAs were further examined by quantitative real-time PCR (qRT-PCR) in the same small set of patients. After the training phase of screening and selecting, the candidate miRNAs were validated in a larger independent cohort (80 CaP, 44 BPH, and 54 healthy controls) with qRT-PCR in the verification phase.

RESULTS

Five miRNAs were confirmed by qRT-PCR analysis in validation sets. Receiver operating characteristic (ROC) curve analysis showed all 5 miRNAs had diagnostic value. More importantly, further principal component analysis indicated component 1 extracted from expression data of the 5 miRNAs could differentiate CaP from BPH and healthy controls with high diagnosis performance, with an AUC of 0.924 and 0.860, respectively.

CONCLUSIONS

Our data suggested that circulating miRNAs could serve as biomarkers for CaP, and compared to single miRNA, the 5 miRNAs panel can accurately discriminate CaP from BPH and healthy controls with high sensitivity and specificity, and therefore, combined with routine PSA test, these 5 CaP-specific miRNAs may help improve CaP diagnosis in clinical application.

Active surveillance for prostate cancer: past, present and future

PURPOSE OF REVIEW

This article reviews recent developments in the use of active surveillance for localized prostate cancer.

RECENT FINDINGS

The treatment of localized prostate cancer continues to be a major challenge for urologic oncologists. Screening with prostate-specific antigen has resulted in increased numbers of low-risk prostate cancers being detected. Aggressive whole-gland therapy with surgery, or radiation therapy is associated with potentially life-altering treatment-related side effects such as urinary incontinence, bowel toxicity and erectile dysfunction. The goal of active surveillance is to avoid or delay the adverse events associated with prostate cancer therapy while still allowing for curative intervention in the future, if needed.

SUMMARY

Active surveillance is a reasonable treatment option for many men with low-risk, and some men with intermediate-risk, prostate cancer. Additional research is needed to determine the optimal active surveillance inclusion criteria, monitoring schedule, and treatment triggers. It is hoped that advances in prostate imaging, biomarkers, and focal therapy will foster greater use of active surveillance in appropriately selected men to optimize quality-of-life without compromising cancer outcomes.

Prostate cancer: feasibility and preliminary experience of a diffusional kurtosis model for detection and assessment of aggressiveness of peripheral zone cancer

PURPOSE

To assess the feasibility of diffusional kurtosis (DK) imaging for distinguishing benign from malignant regions, as well as low- from high-grade malignant regions, within the peripheral zone (PZ) of the prostate in comparison with standard diffusion-weighted (DW) imaging.

MATERIALS AND METHODS

The institutional review board approved this retrospective HIPAA-compliant study and waived informed consent. Forty-seven patients with prostate cancer underwent 3-T magnetic resonance imaging by using a pelvic phased-array coil and DW imaging (maximum b value, 2000 sec/mm2). Parametric maps were obtained for apparent diffusion coefficient (ADC); the metric DK (K), which represents non-Gaussian diffusion behavior; and corrected diffusion (D) that accounts for this non-Gaussianity. Two radiologists reviewed these maps and measured ADC, D, and K in sextants positive for cancer at biopsy. Data were analyzed by using mixed-model analysis of variance and receiver operating characteristic curves.

RESULTS

Seventy sextants exhibited a Gleason score of 6; 51 exhibited a Gleason score of 7 or 8. K was significantly greater in cancerous sextants than in benign PZ (0.96±0.24 vs 0.57±0.07, P<.001), as well as in cancerous sextants with higher rather than lower Gleason score (1.05±0.26 vs 0.89±0.20, P<.001). K showed significantly greater sensitivity for differentiating cancerous sextants from benign PZ than ADC or D (93.3% vs 78.5% and 83.5%, respectively; P<.001), with equal specificity (95.7%, P>.99). K exhibited significantly greater sensitivity for differentiating sextants with low- and high-grade cancer than ADC or D (68.6% vs 51.0% and 49.0%, respectively; P≤.004) but with decreased specificity (70.0% vs 81.4% and 82.9%, respectively; P≤.023). K had significantly greater area under the curve for differentiating sextants with low- and high-grade cancer than ADC (0.70 vs 0.62, P=.010). Relative contrast between cancerous sextants and benign PZ was significantly greater for D or K than ADC (0.25±0.14 and 0.24±0.13, respectively, vs 0.18±0.10; P<.001).

CONCLUSION

Preliminary findings suggest increased value for DK imaging compared with standard DW imaging in prostate cancer assessment.

Prostate cancer risk variants are not associated with disease progression

BACKGROUND

Currently used prognostic markers are limited in their ability to accurately predict disease progression among patients with localized prostate cancer. We examined 23 reported prostate cancer susceptibility variants for association with disease progression.

METHODS

Disease progression was explored among 4,673 Swedish patients treated for clinically localized prostate cancer between 1997 and 2002. Prostate cancer progression was defined according to primary treatment as a composed event reflecting termination of deferred treatment, biochemical recurrence, local progression, or presence of distant metastasis. Association between single variants, and all variants combined, were performed in Cox regression analysis assuming both log-additive and co-dominant genetic models.

RESULTS

Three of the 23 genetic variants explored were nominally associated with prostate cancer progression; rs9364554 (P = 0.041) on chromosome 6q25 and rs10896449 (P = 0.029) on chromosome 11q13 among patients treated with curative intent; and rs4054823 (P = 0.008) on chromosome 17p12 among patients on surveillance. However, none of these associations remained statistically significant after correction for multiple testing. The combined effect of all susceptibility variants was not associated with prostate cancer progression neither among patients receiving treatment with curative intent (P = 0.14) nor among patients on surveillance (P = 0.92).

CONCLUSIONS

We observed no evidence for an association between any of 23 established prostate cancer genetic risk variants and disease progression. Accumulating evidence suggests separate genetic components for initiation and progression of prostate cancer. Future studies systematically searching for genetic risk variants associated with prostate cancer progression and prognosis are warranted.

Transrectal ultrasonography-guided biopsy does not reliably identify dominant cancer location in men with low-risk prostate cancer

Study Type - Diagnostic (exploratory cohort) Level of Evidence 2b What's known on the subject? and What does the study add? The widespread use of serum PSA testing followed by TRUS-guided biopsy have resulted in profound prostate cancer stage migration with many patients presenting with focal rather than multifocal disease. There is increasing interest in the use of focal rather than whole-gland treatment. However, current biopsy schemes may still miss cancer or, even when cancer is identified, its extent or grade might not be accurately characterized. In order for focal therapy to be effective, the area of highest tumour volume and/or grade needs to localized accurately. The aim of this study was to assess how well biopsy, as currently performed, locates the focus of highest prostate cancer volume and/or grade.

OBJECTIVE

To evaluate the ability of transrectal ultrasonography (TRUS)-guided extended core biopsy to identify the dominant tumour accurately in men with early stage prostate cancer.

PATIENTS AND METHODS

Patients with early stage, low-risk prostate cancer who subsequently underwent radical prostatectomy (RP) and had complete surgical specimens were identified. Re-review was performed by a single uropathologist using ImageJ software to identify tumour location, dominant grade (DG) and dominant volume (DV). Pathology findings were then compared with biopsy results.

RESULTS

A total of 51 men with early stage, low-risk prostate cancer, who had undergone RP, had complete specimens for review and a median of 15 biopsy cores taken for diagnosis and grading. Sixteen men had a single diagnostic biopsy, 21 had one repeat biopsy, and 14 had two or more repeat biopsies. Compared with surgical findings, biopsy correctly identified the sextant with the largest tumour volume in 55% (95% CI 0.5-0.6) of specimens and the highest grade in 37% (95 CI 0.3-0.5). No demographic or clinical factors were significantly associated with identification of DG. Interval between last biopsy and RP, total tissue length taken and total length of tumour identified were significantly associated with correct identification of DV.

CONCLUSIONS

Our findings show that TRUS-guided biopsy detects and localizes DV better than it does DG. Even with an extended scheme, TRUS-guided biopsy does not reliably identify dominant cancer location in this low-risk cohort of men with early stage prostate cancer. TRUS-guided biopsy may perform better in similar men with low stage, but higher volume disease.

[EAU guidelines on prostate cancer. Part I: screening, diagnosis, and treatment of clinically localised disease]

OBJECTIVE

Our aim was to present a summary of the 2010 version of the European Association of Urology (EAU) guidelines on the screening, diagnosis, and treatment of clinically localised cancer of the prostate (PCa).

METHODS

The working panel performed a literature review of the new data emerging from 2007 to 2010. The guidelines were updated, and level of evidence and grade of recommendation were added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews.

RESULTS

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

CONCLUSIONS

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

Impact of annual surgical volume on length of stay in patients undergoing minimally invasive prostatectomy: a population-based study

BACKGROUND

On average, patients remain hospitalized no more than 2 days after MIRP. The aim of our study was to examine the temporal trends in length of stay ≥ 3 days and to test the relationship between annual surgical volume (ASV) and annual hospital volume (AHV) and length of stay ≥ 3 days in patients undergoing MIRP.

MATERIAL AND METHODS

Within the Florida Hospital Inpatient Datafile, 2439 men who were treated with MIRP for prostate cancer between 2005 and 2008 were identified. Temporal trends were assessed and uni and multi-variable logistic regression models tested the relationship between ASV, AHV and length of stay ≥ 3 days.

RESULTS

The average length of stay decreased from 2.4 in 2005 to 1.7 days in 2008. Length of stay ≥ 3 days was recorded in 13.6% of patients and the proportion of patients staying more than ≥ 3 days decreased over time (25.5-12.2%; Chi Square trend p < 0.001). After stratification into low (<1-15 MIRPs) vs. intermediate (16-63 MIRPs) vs. high ASV tertiles (≥ 64 MIRPs) the proportion of patients with length of stay ≥ 3 days were 29.1; 13.2 and 11.1%. In multivariable logistic regression models predicting length of stay ≥ 3 days, ASV, year of surgery and comorbidities achieved independent predictor status and MIRP patients operated by highest ASV tertile surgeons were 71% (p < 0.001) less likely to be hospitalized for more than 3 days.

CONCLUSION

The length of stay after MIRP decreased between 2005 and 2008. Surgical expertise represented one of the main determinants of shorter length of stay.

Active Surveillance Program for Prostate Cancer: An Update of the Johns Hopkins Experience

Purpose

We assessed outcomes of men with prostate cancer enrolled in active surveillance.

Patients and Methods

Since 1995, a total of 769 men diagnosed with prostate cancer have been followed prospectively (median follow-up, 2.7 years; range, 0.01 to 15.0 years) on active surveillance. Enrollment criteria were for very-low-risk cancers, defined by clinical stage (T1c), prostate-specific antigen density < 0.15 ng/mL, and prostate biopsy findings (Gleason score ≤ 6, two or fewer cores with cancer, and ≤ 50% cancer involvement of any core). Curative intervention was recommended on disease reclassification on the basis of biopsy criteria. The primary outcome was survival free of intervention, and secondary outcomes were rates of disease reclassification and exit from the program. Outcomes were compared between men who did and did not meet very-low-risk criteria.

Results

The median survival free of intervention was 6.5 years (range, 0.0 to 15.0 years) after diagnosis, and the proportions of men remaining free of intervention after 2, 5, and 10 years of follow-up were 81%, 59%, and 41%, respectively. Overall, 255 men (33.2%) underwent intervention at a median of 2.2 years (range, 0.6 to 10.2 years) after diagnosis; 188 men (73.7%) underwent intervention on the basis of disease reclassification on biopsy. The proportions of men who underwent curative intervention (P = .026) or had biopsy reclassification (P < .001) were significantly lower in men who met enrollment criteria than in those who did not. There were no prostate cancer deaths.

Conclusion

For carefully selected men, active surveillance with curative intent appears to be a safe alternative to immediate intervention. Limiting surveillance to very-low-risk patients may reduce the frequency of adverse outcomes.

Delay of surgery in men with low risk prostate cancer

PURPOSE

Treatment options for patients with low risk prostate cancer include radical prostatectomy, radiation therapy, and active surveillance. Among patients treated with radical prostatectomy, prior studies have demonstrated significantly higher biochemical progression rates with surgical delays of 6 months or greater. We determined the impact of surgical delay on radical prostatectomy outcomes specifically in low risk patients.

MATERIALS AND METHODS

From our radical prostatectomy database we identified men who fulfilled the D'Amico low risk criteria (clinical stage T1c/T2a, prostate specific antigen less than 10 ng/ml, and biopsy Gleason 6 or less). Pathological tumor features and biochemical progression rates were compared between men with and without surgical delay. We used Cox proportional hazards models to examine predictors of biochemical progression.

RESULTS

Of 1,111 men who fulfilled the D'Amico low risk criteria, those with a surgical delay of 6 months or more were significantly older, had a higher proportion of African American men, and a lower proportion of clinical stage T2a (vs T1). A surgical delay of 6 months or more was associated with a greater risk of high grade disease at prostatectomy (p = 0.001) and biochemical progression (p = 0.04). The progression-free survival rate was significantly lower among men with a surgical delay. On multivariate analysis with prostate specific antigen and clinical stage, surgical delays of 6 months or more were significantly and independently associated with time to biochemical progression.

CONCLUSIONS

In men who met the D'Amico low risk criteria, a surgical delay of 6 months or more was associated with significantly worse radical prostatectomy outcomes, including more pathology upgrading and a higher rate of biochemical progression. Low risk patients choosing to defer initial definitive therapy should be counseled regarding the possibility of worse treatment outcomes at a later date.