Performance of transperineal template-guided mapping biopsy in detecting prostate cancer in the initial and repeat biopsy setting. Prostate Cancer Prostatic Dis. 2010;13:71-77. [PMID: 19786982 PMCID: PMC2834351 DOI: 10.1038/pcan.2009.42]

Absence of Bladder Outlet Obstruction Is an Independent Risk Factor for Prostate Cancer in Men Undergoing Prostate Biopsy

The purpose of this study was to investigate the relationship between bladder outlet obstruction (BOO) and the risk of being diagnosed with prostate cancer (PCa).Study population consisted of 2673 patients scheduled for the first prostate biopsy (PBx). All patients underwent uroflowmetry before PBx; those with a peak flow rate (PFR) <10 mL/s were considered to have BOO.The incidence of PCa was 41.3% (1104/2673) in the overall population and 34.1% (659/1905) in patients with serum prostate-specific antigen (PSA) ≤ 10 ng/mL. Univariate and multivariate logistic regression analyses showed that patients with BOO had a significantly (P < 0.0001) lower risk than those without BOO of being diagnosed with PCa (33.1% vs 66.9% in the overall population; 30% vs 70% in patients with PSA ≤ 10 ng/mL). As the presence of BOO was significantly correlated to a large prostate volume, another independent predictor of PBx outcome, we tested whether these parameters could be used to identify, in the subset of patients with PSA≤10 ng/mL, those who could potentially be spared from a PBx. If we would have not biopsied patients with BOO and prostate volume ≥60 mL, 14.5% of biopsies could have been avoided while missing only 6% of tumors. Only 10% of the tumors that would have been missed were high-risk cancers.In conclusion, in men undergoing PBx, the absence of BOO, as determined by a PFR ≥10 mL/s, is an independent risk factor for PCa. Our study provides ground for this simple, noninvasive, objective parameter being used, alone or in combination with prostate volume, in the decision-making process of men potentially facing a PBx.

Prostate cancer detection with magnetic resonance-ultrasound fusion biopsy: The role of systematic and targeted biopsies

BACKGROUND

The current study was conducted to evaluate the performance of magnetic resonance (MR)-ultrasound-guided fusion biopsy in diagnosing clinically significant prostate cancer (csCaP).

METHODS

A total of 1042 men underwent multiparametric MR imaging (mpMRI) and fusion biopsy consecutively in a prospective trial (2009-2014). An expert reader graded mpMRI regions of interest (ROIs) as 1 to 5 using published protocols. The fusion biopsy device was used to obtain targeted cores from ROIs (when present) followed by a fusion image-guided, 12-core systematic biopsy in all men, even if no suspicious ROI was noted. The primary endpoint of the study was the detection of csCaP (ie, Gleason score ≥ 7).

RESULTS

Among 825 men with ≥ 1 suspicious ROI of ≥ grade 3, 289 (35%) were found to have csCaP. Powerful predictors of csCaP were ROI grade (grade 5 vs grade 3: odds ratio, 6.5 [P<.01]) and prostate-specific antigen density (each increase of 0.05 ng/mL/cc: odds ratio, 1.4 [P<.01]). Combining systematic and targeted biopsies resulted in the detection of more patients with csCaP (289 patients) than targeting (229 patients) or systematic (199 patients) biopsy alone. Among patients with no suspicious ROI, 35 (16%) were found to have csCaP on systematic biopsy.

CONCLUSIONS

In this prospective trial, MR-ultrasound fusion biopsy allowed for the detection of csCaP, with a direct relationship noted with ROI grade and prostate-specific antigen density. The combination of targeted and systematic biopsy detected more csCaP than either modality alone; systematic biopsies revealed csCaP in 16% of men with no suspicious MRI target. The advantages of this new biopsy method are apparent, but issues of cost, training, and reliability await resolution before its widespread adoption.

Initial Experience of Targeted Focal Interstitial Laser Ablation of Prostate Cancer with MRI Guidance

Introduction

To develop and evaluate a technique of 3.0 Tesla magnetic resonance (MR) guided laser ablation based on 3-dimentional mapping biopsy (3DMB) for low risk prostate cancer.

Materials and Methods

The study was approved by the institutional review board and was the Health Insurance Portability and Accountability Act compliant. The prospective study was performed on seven 3DMB proven low risk prostate cancer patients. In the first phase of the procedure the patient's prostate was aligned to a position concordant with prior 3DMB using the transperineal grid and fiduciary golden marker coordinates. In the second phase ablation was performed using MR thermometry to determine the ablation endpoint and lesion coverage. Immediately after treatment dynamic contrast-enhanced MR imaging was done. Prostate-specific antigen testing was performed 3 and 12 months after the treatment and compared by ANOVA test. A follow up biopsy was done one year following ablation.

Results

The entire procedure took less than 2 hours and all patients tolerated the procedure well. There was a significant difference in prostate-specific antigen value before and 3 months after the treatment (p = 0.005). Four out of 6 patients had positive follow up biopsy for cancer.

Conclusion

This study verifies the feasibility and safety of treating low risk prostate cancer with laser therapy guided by 3.0T MR imaging based on 3DMB.

Quantifying Gleason scores with photoacoustic spectral analysis: feasibility study with human tissues

Gleason score is a highly prognostic factor for prostate cancer describing the microscopic architecture of the tumor tissue. The standard procedure for evaluating Gleason scores, namely biopsy, is to remove prostate tissue for observation under microscope. Currently, biopsies are guided by transrectal ultrasound (TRUS). Due to the low sensitivity of TRUS to prostate cancer (PCa), non-guided and saturated biopsies are frequently employed, unavoidably causing pain, damage to the normal prostate tissues and other complications. More importantly, due to the limited number of biopsy cores, current procedure could either miss early stage small tumors or undersample aggressive cancers. Photoacoustic (PA) measurement has the unique capability of evaluating tissue microscopic architecture information at ultrasonic resolution. By frequency domain analysis of the broadband PA signal, namely PA spectral analysis (PASA), the microscopic architecture within the assessed tissue can be quantified. This study investigates the feasibility of evaluating Gleason scores by PASA. Simulations with the classic Gleason patterns and experiment measurements from human PCa tissues have demonstrated strong correlation between the PASA parameters and the Gleason scores.

Active surveillance for prostate cancer

It is worth distinguishing between the two strategies of expectant management for prostate cancer. Watchful waiting entails administering non-curative androgen deprivation therapy to patients on development of symptomatic progression, whereas active surveillance entails delivering curative treatment on signs of disease progression. The objectives of the two management strategies and the patients enrolled in either are different: (i) to review the role of active surveillance as a management strategy for patients with low-risk prostate cancer; and (ii) review the benefits and pitfalls of active surveillance. We carried out a systematic review of active surveillance for prostate cancer in the literature using the National Center for Biotechnology Information's electronic database, PubMed. We carried out a search in English using the terms: active surveillance, prostate cancer, watchful waiting and conservative management. Selected studies were required to have a comprehensive description of the demographic and disease characteristics of the patients at the time of diagnosis, inclusion criteria for surveillance, and a protocol for the patients' follow up. Review articles were included, but not multiple papers from the same datasets. Active surveillance appears to reduce overtreatment in patients with low-risk prostate cancer without compromising cancer-specific survival at 10 years. Therefore, active surveillance is an option for select patients who want to avoid the side-effects inherent to the different types of immediate treatment. However, inclusion criteria for active surveillance and the most appropriate method of monitoring patients on active surveillance have not yet been standardized.

The Prevalence of Clinically Significant Prostate Cancer According to Commonly Used Histological Thresholds in Men Undergoing Template Prostate Mapping Biopsies

PURPOSE

Transrectal prostate biopsies are inaccurate and, thus, the prevalence of clinically significant prostate cancer in men undergoing biopsy is unknown. We determined the ability of different histological thresholds to denote clinically significant cancer in men undergoing a more accurate biopsy, that of transperineal template prostate mapping.

MATERIALS AND METHODS

In this multicenter, cross-sectional cohort of men who underwent template prostate mapping biopsies between May 2006 and January 2012, 4 different thresholds of significance combining tumor grade and burden were used to measure the consequent variation with respect to the prevalence of clinically significant disease.

RESULTS

Of 1,203 men 17% (199) had no previous biopsy, 38% (455) had a prior negative transrectal ultrasound biopsy, 24% (289) were on active surveillance and 21% (260) were seeking risk stratification. Mean patient age was 63.5 years (SD 7.6) and median prostate specific antigen was 7.4 ng/ml (IQR 5.3-10.5). Overall 35% of the patients (424) had no cancer detected. The prevalence of clinically significant cancer varied between 14% and 83% according to the histological threshold used, in particular between 30% and 51% among men who had no previous biopsy, between 14% and 27% among men who had a prior negative biopsy, between 36% and 74% among men on active surveillance, and between 47% and 83% among men seeking risk stratification.

CONCLUSIONS

According to template prostate mapping biopsy between 1 in 2 and 1 in 3 men have prostate cancer that is histologically defined as clinically significant. This suggests that the commonly used thresholds may be set too low.

Three-dimensional printing technique assisted cognitive fusion in targeted prostate biopsy

Objective

To explore the effect of 3-dimensional (3D) printing-assisted cognitive fusion on improvement of the positive rate in prostate biopsy.

Methods

From August to December 2014, 16 patients with suspected prostatic lesions detected by multiparametric magnetic resonance imaging (MRI) were included. Targeted prostate biopsy was performed with the use of prostate 3D reconstruction modeling, computer-simulated biopsy, 3D printing, and cognitive fusion biopsy. All patients had received 3.0 T multiparametric MRI before biopsy. The DICOM MRI files were imported to medical imaging processing software for 3D reconstruction modeling to generate a printable .stl file for 3D printing with use of transparent resin as raw material. We further performed a targeted 2- to 3-core biopsy at suspected lesions spotted on MRI.

Results

For the 16 patients in the present study, 3D modeling with cognitive fusion-based targeted biopsy was successfully performed. For a single patient, 1–2 lesions (average: 1.1 lesions) were discovered, followed by 2–6 cores (average: 2.4 cores) added as targeted biopsy. Systematic biopsies accounted for 192 cores in total, with a positive rate of 22.4%; targeted biopsies accounted for 39 cores in total, with a positive rate of 46.2%. Among these cases, 10 patients (62.5%) were diagnosed with prostate adenocarcinoma, in which seven were discovered by both systematic and targeted biopsy, one was diagnosed by systematic biopsy only, and two were diagnosed by targeted biopsy only. For systematic biopsy, Gleason score ranged from 6 to 8 (average: 7), while that for targeted biopsy ranged from 6 to 9 (average: 7.67). Among the seven patients that were diagnosed by both systematic and targeted biopsy, three (42.8%) were reported with a higher Gleason score in targeted therapy than in systematic biopsy.

Conclusion

3D printing-assisted cognitive fusion technique markedly promoted positive rate in prostate biopsy, and reduced missed detection in high-risk prostate cancer.

Zone-specific logistic regression models improve classification of prostate cancer on multi-parametric MRI

OBJECTIVES

To assess the interchangeability of zone-specific (peripheral-zone (PZ) and transition-zone (TZ)) multiparametric-MRI (mp-MRI) logistic-regression (LR) models for classification of prostate cancer.

METHODS

Two hundred and thirty-one patients (70 TZ training-cohort; 76 PZ training-cohort; 85 TZ temporal validation-cohort) underwent mp-MRI and transperineal-template-prostate-mapping biopsy. PZ and TZ uni/multi-variate mp-MRI LR-models for classification of significant cancer (any cancer-core-length (CCL) with Gleason > 3 + 3 or any grade with CCL ≥ 4 mm) were derived from the respective cohorts and validated within the same zone by leave-one-out analysis. Inter-zonal performance was tested by applying TZ models to the PZ training-cohort and vice-versa. Classification performance of TZ models for TZ cancer was further assessed in the TZ validation-cohort. ROC area-under-curve (ROC-AUC) analysis was used to compare models.

RESULTS

The univariate parameters with the best classification performance were the normalised T2 signal (T2nSI) within the TZ (ROC-AUC = 0.77) and normalized early contrast-enhanced T1 signal (DCE-nSI) within the PZ (ROC-AUC = 0.79). Performance was not significantly improved by bi-variate/tri-variate modelling. PZ models that contained DCE-nSI performed poorly in classification of TZ cancer. The TZ model based solely on maximum-enhancement poorly classified PZ cancer.

CONCLUSION

LR-models dependent on DCE-MRI parameters alone are not interchangable between prostatic zones; however, models based exclusively on T2 and/or ADC are more robust for inter-zonal application.

KEY POINTS

• The ADC and T2-nSI of benign/cancer PZ are higher than benign/cancer TZ. • DCE parameters are significantly different between benign PZ and TZ, but not between cancerous PZ and TZ. • Diagnostic models containing contrast enhancement parameters have reduced performance when applied across zones.

Targeted prostate biopsy: value of multiparametric magnetic resonance imaging in detection of localized cancer

Prostate cancer is the second most common cancer in men, with 1.1 million new cases worldwide reported by the World Health Organization in one recent year. Transrectal ultrasound (TRUS)-guided biopsy has been used for the diagnosis of prostate cancer for over 2 decades, but the technique is usually blind to cancer location. Moreover, the false negative rate of TRUS biopsy has been reported to be as high as 47%. Multiparametric magnetic resonance imaging (mp-MRI) includes T1- and T2-weighted imaging as well as dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI). mp-MRI is a major advance in the imaging of prostate cancer, enabling targeted biopsy of suspicious lesions. Evolving targeted biopsy techniques-including direct in-bore biopsy, cognitive fusion and software-based MRI-ultrasound (MRI-US) fusion-have led to a several-fold improvement in cancer detection compared to the earlier method. Importantly, the detection of clinically significant cancers has been greatly facilitated by targeting, compared to systematic biopsy alone. Targeted biopsy via MRI-US fusion may dramatically alter the way prostate cancer is diagnosed and managed.

Preoperative Serum Prostate-Specific Antigen Levels Vary According to the Topographical Distribution of Prostate Cancer in Prostatectomy Specimens

OBJECTIVE

To evaluate whether the spatial distribution of prostate cancer (PCa) influences the concentration of prostate-specific antigen (PSA).

METHODS

An observational prospective study was performed in 775 consecutive men with preoperative PSA levels ≤20 ng/mL who underwent radical prostatectomy for organ-confined PCa. We evaluated prostate specimens using a cMDX-based map model of the prostate and determined the prostate volume, number of cancer foci, relative tumor volume, Gleason score, zone of origin, localization, and pathologic stage after stratification according to PSA levels categorized into 3 groups: <4 ng/mL, 4-10 ng/mL, and 10.1-20 ng/mL. The distribution of 5254 PCa foci was analyzed after stratification according to PSA levels and visualized on heat maps. A logistic regression analysis was performed to assess the odds ratios of PSA levels for the presence of PCa in 16 regions.

RESULTS

PCa with PSA <4 ng/mL was predominantly localized to the apical part and the peripheral zone of the prostate. PCa with a PSA level 10.1-20 ng/mL (16.4% of cases) was observed more frequently in the anterior part and the base of the prostate than PCa with a PSA level <4 or 4-10 ng/mL (6% and 10%, respectively).

CONCLUSION

Preoperative PSA levels vary according to the spatial distribution of PCa in radical prostatectomy specimens. The probability of anterior PCa is increased with higher PSA serum levels. Regions of interest harboring the PCa can be defined according to preoperative PSA and prostate volume. These findings are useful to optimize the focal therapy or to adjust the radiation fields.

Expectant management for men with early stage prostate cancer

Since the dissemination of prostate-specific antigen screening, most men with prostate cancer are now diagnosed with localized, low-risk prostate cancer that is unlikely to be lethal. Nevertheless, nearly all of these men undergo primary treatment with surgery or radiation, placing them at risk for longstanding side effects, including erectile dysfunction and impaired urinary function. Active surveillance and other observational strategies (ie, expectant management) have produced excellent long-term disease-specific survival and minimal morbidity for men with prostate cancer. Despite this, expectant management remains underused for men with localized prostate cancer. In this review, various approaches to the expectant management of men with prostate cancer are summarized, including watchful waiting and active surveillance strategies. Contemporary cancer-specific and health care quality-of-life outcomes are described for each of these approaches. Finally, contemporary patterns of use, potential disparities in care, and ongoing research and controversies surrounding expectant management of men with localized prostate cancer are discussed.

Repeat Targeted Prostate Biopsy under Guidance of Multiparametric MRI-Correlated Real-Time Contrast-Enhanced Ultrasound for Patients with Previous Negative Biopsy and Elevated Prostate-Specific Antigen: A Prospective Study

OBJECTIVES

To prospectively determine whether multi-parametric MRI (mpMRI) - contrast-enhanced ultrasound (CEUS) correlated, imaging-guided target biopsy (TB) method could improve the detection of prostate cancer in re-biopsy setting of patients with prior negative biopsy.

METHODS

From 2012 to 2014, a total of 42 Korean men with a negative result from previous systematic biopsy (SB) and elevated prostate-specific antigen underwent 3T mpMRI and real-time CEUS guided TB. Target lesions were determined by fusion of mpMRI and CEUS. Subsequently, 12-core SB was performed by a different radiologist. We compared core-based cancer detection rates (CaDR) using the generalized linear mixed model (GLIMMIX) for each biopsy method.

RESULTS

Core-based CaDR was higher in TB (17.92%, 38 of 212 cores) than in SB (6.15%, 31 of 504 cores) (p < 0.0001; GLIMMIX). In the cancer-positive TB cores, CaDR with suspicious lesions by mpMRI was higher than that by CEUS (86.8% vs. 60.5%, p= 0.02; paired t-test) and concordant rate between mpMRI and CEUS was significantly different with discordant rate (48% vs. 52%, p=0.04; McNemar's test).

CONCLUSION

The mpMRI-CEUS correlated TB technique for the repeat prostate biopsy of patients with prior negative biopsy can improve CaDR based on the number of cores taken.

Multiparametric magnetic resonance imaging for prostate cancer improves Gleason score assessment in favorable risk prostate cancer

PURPOSE

Magnetic resonance imaging (MRI) guidance may improve the accuracy of Gleason score (GS) determination by directing the biopsy to regions of interest (ROI) that are likely to harbor high-grade prostate cancer (CaP). The aim of this study was to determine the frequency and predictors of GS upgrading when a subsequent MRI-guided biopsy is performed on patients with a diagnosis of GS 6 disease on the basis of conventional, transrectal ultrasound-guided biopsy.

METHODS AND MATERIALS

A consecutive series of 245 men with a diagnosis of low-risk CaP (ie, cT1c, GS 6, prostate-specific antigen <10) based on transrectal ultrasound-guided biopsy was enrolled in an active surveillance protocol that used subsequent MRI-guided biopsy for confirmation of GS. ROIs were categorized on a scale of 1 to 5. The Artemis ultrasound-MRI fusion device was used to perform targeted biopsies of ROIs as well as systematic biopsies from a software-based 12-point map. Predictors of GS upgrading were analyzed using univariate and multivariate analyses.

RESULTS

Fusion biopsy resulted in 26% of patients having GS upgrading (GS 3+4 in 18%, 4+3 in 5%, and 8-9 in 3%). Of the 72% of patients with ROIs appropriate for targeting, targeted cores upgraded the GS in 18%, whereas systematic cores upgraded the GS in 24%. In patients without targeted biopsy, GS upgrading was seen in 14%. On multivariate analysis, a category 5 ROI was the most significant predictor of GS upgrading with an odds ratio of 10.56 (P < .01).

CONCLUSIONS

Nearly 25% of men with GS 6 CaP diagnosed by standard transrectal ultrasound biopsy may experience GS upgrading when a subsequent MRI-ultrasound fusion biopsy is performed. The most important single predictor of upgrading is a category 5 ROI on multiparametric MRI. GS upgrading may influence treatment decisions. Therefore, MRI-guided biopsy should be considered prior to formulating a management strategy in patients whose conventional biopsy reveals low-risk CaP.

PROMIS--Prostate MR imaging study: A paired validating cohort study evaluating the role of multi-parametric MRI in men with clinical suspicion of prostate cancer

BACKGROUND

Transrectal ultrasound-guided prostate biopsies are prone to detection errors. Multi-parametric MRI (MP-MRI) may improve the diagnostic pathway.

METHODS

PROMIS is a prospective validating paired-cohort study that meets criteria for level 1 evidence in diagnostic test evaluation. PROMIS will investigate whether multi-parametric (MP)-MRI can discriminate between men with and without clinically-significant prostate cancer who are at risk prior to first biopsy. Up to 714 men will have MP-MRI (index), 10-12 core TRUS-biopsy (standard) and 5mm transperineal template mapping (TPM) biopsies (reference). The conduct and reporting of each test will be blinded to the others.

RESULTS

PROMIS will measure and compare sensitivity, specificity, and positive and negative predictive values of both MP-MRI and TRUS-biopsy against TPM biopsies. The MP-MRI results will be used to determine the proportion of men who could safely avoid biopsy without compromising detection of clinically-significant cancers. For the primary outcome, significant cancer on TPM is defined as Gleason grade >/= 4+3 and/or maximum cancer core length of ≥ 6 mm. PROMIS will also assess inter-observer variability among radiologists among other secondary outcomes. Cost-effectiveness of MP-MRI prior to biopsy will also be evaluated.

CONCLUSIONS

PROMIS will determine whether MP-MRI of the prostate prior to first biopsy improves the detection accuracy of clinically-significant cancer.

Transperineal biopsy prostate cancer detection in first biopsy and repeat biopsy after negative transrectal ultrasound-guided biopsy: the Victorian Transperineal Biopsy Collaboration experience

OBJECTIVES

To present the Victorian Transperineal Biopsy Collaboration (VTBC) experience in patients with no prior prostate cancer diagnosis, assessing the cancer detection rate, pathological outcomes and anatomical distribution of cancer within the prostate.

PATIENTS AND METHODS

VTBC was established through partnership between urologists performing transperineal biopsies of the prostate (TPB) at three institutions in Melbourne. Consecutive patients who had TPB, as first biopsy or repeat biopsy after previous negative transrectal ultrasound-guided (TRUS) biopsy, between September 2009 and September 2013 in the VTBC database were included. Data for each patient were collected prospectively (except for TPB before 2011 in one institution), based on the minimum dataset published by the Ginsburg Study Group. Univariate and multivariate analyses were used to identify factors predictive of cancer detection on TPB.

RESULTS

In all, 160 patients were included in the study, of whom 57 had TPB as first biopsy and 103 had TPB as repeat biopsy after previous negative TRUS biopsies. The median patient age at TPB was 63 years, with the repeat-biopsy patients having a higher median serum PSA level (5.8 ng/mL for first biopsy and 9.6 ng/mL for repeat biopsy) and larger prostate volumes (40 mL for first biopsy, and 51 mL for repeat biopsy). Prostate cancer was detected in 53% of first-biopsy patients and 36% of repeat-biopsy patients, of which 87% and 81%, respectively, were clinically significant cancers, defined as a Gleason score of ≥7, or more than three positive cores of Gleason 6. Of the cancers detected in repeat biopsies, 75% involved the anterior region (based on the Ginsburg Study Group's recommended biopsy map), while 25% were confined exclusively within the anterior region; a lower proportion of only 5% of cancers detected in first biopsies were confined exclusively within the anterior region. Age, serum PSA level and prostate volume were predictive of cancer detection in repeat biopsies, while only age was predictive in first biopsies.

CONCLUSIONS

TPB is an alternative approach to TRUS biopsy of the prostate, offering a high rate of detection of clinically significant prostate cancer. It provides excellent sampling of the anterior region of the prostate, which is often under-sampled using the TRUS approach, and should be considered as an option for all men in whom a prostate biopsy is indicated.

Role of transperineal template biopsy in prostate cancer

Prostate cancer is the most common neoplasm diagnosed in men. Whilst treatment modalities have progressed, diagnostic investigations in terms of biopsy methods have been assessed but there is no consensus of when the different diagnostic methods in terms of transrectal ultrasound (TRUS) or transperineal template (TPT) should be utilised. TPT biopsy has a higher diagnostic yield than TRUS in those with a primary biopsy, in those with previous negative biopsies with TRUS as well as those undergoing saturation biopsies. Despite the increased likelihood of diagnosing cancer with TPT than TRUS this maybe secondary to the increased number of biopsies being utilised. However there is no consensus regarding the ideal number of biopsies that should be utilised with TPT. Furthermore it is felt that the increased number of biopsies utilised with TPT is associated the higher complication rates with TPT. The role of TPT biopsy is recognised in those with previous negative biopsies with transrectal ultrasound but further work is required regarding the ideal number of biopsies. Furthermore, it is felt that TPT biopsy may have a role in primary biopsy.

Computer-Aided Detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: a review

Prostate cancer is the second most diagnosed cancer of men all over the world. In the last few decades, new imaging techniques based on Magnetic Resonance Imaging (MRI) have been developed to improve diagnosis. In practise, diagnosis can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. In this regard, computer-aided detection and computer-aided diagnosis systems have been designed to help radiologists in their clinical practice. Research on computer-aided systems specifically focused for prostate cancer is a young technology and has been part of a dynamic field of research for the last 10 years. This survey aims to provide a comprehensive review of the state-of-the-art in this lapse of time, focusing on the different stages composing the work-flow of a computer-aided system. We also provide a comparison between studies and a discussion about the potential avenues for future research. In addition, this paper presents a new public online dataset which is made available to the research community with the aim of providing a common evaluation framework to overcome some of the current limitations identified in this survey.

Can Clinically Significant Prostate Cancer Be Detected with Multiparametric Magnetic Resonance Imaging? A Systematic Review of the Literature

CONTEXT

Detection of clinically significant prostate cancer (PCa) is a major challenge. It has been shown that multiparametric magnetic resonance imaging (mpMRI) facilitates localisation of PCa and can help in targeting prostate biopsy.

OBJECTIVE

To systematically review the literature to determine the diagnostic accuracy of mpMRI in the detection of clinically significant PCa.

EVIDENCE ACQUISITION

The Pubmed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched from January 1, 2000 to September 30, 2014, using the search criteria "prostate OR Pca OR PSA OR prostatic OR prostate cancer" AND "MR OR NMR OR NMRI OR MRI OR magnetic resonance OR ADC OR DWI OR DCE OR diffusion weighted OR dynamic contrast OR multiparametric OR MRSI OR MR spectroscopy". Two reviewers independently assessed 1729 records. Two independent reviewers assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) 2 tool.

EVIDENCE SYNTHESIS

Twelve articles were eventually selected. Patients had a median age of 62-65 yr (range 39-83 yr), a median prostate-specific antigen (PSA) level of 5.1-13.4 ng/ml (range 1.2-228 ng/ml), and Gleason score of 6-10. Various definitions of clinical significance were used, mainly based on maximum cancer core length and grade at biopsy, number of positive cores, and PSA. Detection of clinically significant PCa using mpMRI ranged from 44% to 87% in biopsy-naïve males and men with prior negative biopsies using prostate biopsy or definitive pathology of a radical prostatectomy specimen as the reference standard. The negative predictive value for exclusion of significant disease ranged from 63% to 98%.

CONCLUSIONS

mpMRI is able to detect significant PCa in biopsy-naïve males and men with prior negative biopsies. The negative predictive value of mpMRI is important to the clinician because mpMRI could be used to rule out significant disease. This may result in fewer or no systematic or targeted biopsies in patients with PSA suspicious for prostate cancer.

PATIENT SUMMARY

We reviewed the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) for the detection of clinically significant prostate cancer (PCa). We conclude that mpMRI is able to detect significant PCa and may used to target prostate biopsies.

Logistic regression model for diagnosis of transition zone prostate cancer on multi-parametric MRI

OBJECTIVES

We aimed to develop logistic regression (LR) models for classifying prostate cancer within the transition zone on multi-parametric magnetic resonance imaging (mp-MRI).

METHODS

One hundred and fifty-five patients (training cohort, 70 patients; temporal validation cohort, 85 patients) underwent mp-MRI and transperineal-template-prostate-mapping (TPM) biopsy. Positive cores were classified by cancer definitions: (1) any-cancer; (2) definition-1 [≥Gleason 4 + 3 or ≥ 6 mm cancer core length (CCL)] [high risk significant]; and (3) definition-2 (≥Gleason 3 + 4 or ≥ 4 mm CCL) cancer [intermediate-high risk significant]. For each, logistic-regression mp-MRI models were derived from the training cohort and validated internally and with the temporal cohort. Sensitivity/specificity and the area under the receiver operating characteristic (ROC-AUC) curve were calculated. LR model performance was compared to radiologists' performance.

RESULTS

Twenty-eight of 70 patients from the training cohort, and 25/85 patients from the temporal validation cohort had significant cancer on TPM. The ROC-AUC of the LR model for classification of cancer was 0.73/0.67 at internal/temporal validation. The radiologist A/B ROC-AUC was 0.65/0.74 (temporal cohort). For patients scored by radiologists as Prostate Imaging Reporting and Data System (Pi-RADS) score 3, sensitivity/specificity of radiologist A 'best guess' and LR model was 0.14/0.54 and 0.71/0.61, respectively; and radiologist B 'best guess' and LR model was 0.40/0.34 and 0.50/0.76, respectively.

CONCLUSIONS

LR models can improve classification of Pi-RADS score 3 lesions similar to experienced radiologists.

KEY POINTS

• MRI helps find prostate cancer in the anterior of the gland • Logistic regression models based on mp-MRI can classify prostate cancer • Computers can help confirm cancer in areas doctors are uncertain about.

MR imaging-guided prostate biopsy techniques

Nearly all prostate biopsies are performed via the transrectal ultrasound (TRUS)-guided technique which suffers from its inability to accurately visualize and target suspicious lesions. Advances in prostate MR imaging now allow for the detection of suspicious regions of the prostate gland, opening the door for lesion-directed biopsy techniques. The ability to obtain a definitive histologic grade has become increasingly important due to the rise of active surveillance as a popular method to approach low-grade cancer. Biopsies obtained with MR guidance or MR imaging/transrectal ultrasound fusion can accurately identify and characterize cancers and thus appropriately stratify patients for specific therapies.

The role of transperineal template biopsies of the prostate in the diagnosis of prostate cancer: a review

The incidence of prostate cancer has shown a significant increase, highlighting the importance of early diagnosis. Current practice considers histological diagnosis a necessity in the majority of the cases. The limitations of transrectal biopsies led to the development of the promising transperineal prostatic biopsies. The latter offers a safer approach by avoiding the rectum, utilizing brachytherapy template grid to detect anterior zone disease and provides accurate prostatic mapping by systematically sampling the whole gland. It also helps to direct biopsies based on images obtained from previous prostate scanning and identify those eligible for focal therapy to direct focal treatment accurately. The current literature provides enough reassurance that transperineal template biopsies are effective, efficient and superior to the traditional and inaccurate transrectal biopsies. The absence of consensus on the technical aspect of template biopsies is a drawback, yet it highlights the need to develop robust guidelines to standardize the procedure.

Prostate cancer: diagnostic performance of real-time shear-wave elastography

PURPOSE

To prospectively evaluate the performance of real-time ultrasonographic (US) shear-wave elastography (SWE) in the diagnosis of peripheral zone prostate cancer in patients with high and/or increasing prostate-specific antigen levels and/or abnormal digital rectal examination results.

MATERIALS AND METHODS

After signing an informed consent form, men referred for transrectal prostate biopsy were enrolled in this prospective HIPAA-compliant two-center study, which was conducted with institutional review board approval. Transrectal US SWE of the prostate was performed after a conventional transrectal US examination and immediately before US-guided 12-core sextant biopsy. For each sextant, the maximum SWE value was measured and matched to the pathologic results of that sextant biopsy. The diagnostic performance of SWE was assessed at both patient and sextant levels. The elasticity value maximizing the Youden index was used to derive sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

The elasticity values were matched to pathologic results for a total of 1040 peripheral zone sextants in 184 men. One hundred twenty-nine positive biopsy findings (size, ≥3 mm; Gleason score, ≥6) were identified in 68 patients. The sextant-level sensitivity, specificity, PPV, NPV, and area under the receiver operating characteristic curve for SWE with a cutoff of 35 kPa for differentiating benign from malignant lesions were 96% (95% confidence interval [CI]: 95%, 97%), 85% (95% CI: 83%, 87%), 48% (95% CI: 46%, 50%), 99% (95% CI: 98%, 100%), and 95% (95% CI: 93%, 97%), respectively.

CONCLUSION

Use of a 35-kPa threshold at SWE may provide additional information for the detection and biopsy guidance of prostate cancer, enabling a substantial reduction in the number of biopsies while ensuring that few peripheral zone adenocarcinomas are missed.

Impact of real-time elastography on magnetic resonance imaging/ultrasound fusion guided biopsy in patients with prior negative prostate biopsies

PURPOSE

The fusion of multiparametric resonance imaging and ultrasound has been proven capable of detecting prostate cancer in different biopsy settings. The addition of real-time elastography promises to increase the precision of the outcome of targeted biopsies. We investigated whether real-time elastography improves magnetic resonance imaging/transrectal ultrasound fusion targeted biopsy in patients after previous negative biopsies.

MATERIALS AND METHODS

Prospectively 121 men underwent 3T magnetic resonance imaging. Using magnetic resonance imaging/real-time elastography fusion every suspicious lesion was characterized according to its tissue density and sampled by 2 fusion guided targeted biopsies. Additionally, all patients underwent 12-core systematic biopsy. The detection rate of clinically significant and insignificant cancers was compared between targeted und systematic biopsies. The accuracy to predict high grade prostate cancer was evaluated for with the PI-RADS scoring system and compared to the magnetic resonance imaging/real-time elastography fusion score.

RESULTS

Overall prostate cancer was detected in 52 patients (43%). Targeted fusion guided biopsy revealed prostate cancer in 32 men (26.4%) and systematic biopsy in 46 (38%). The proportion of clinically significant cancers was higher for targeted biopsy (90.6%) compared to systematic biopsy (73.9%). The detection rate per core was higher for targeted biopsies (14.7%) compared to systematic biopsies (6.5%, p <0.001). The prediction of biopsy result according to magnetic resonance imaging/real-time elastography fusion was better (AUC 0.86) than magnetic resonance imaging alone (AUC 0.79). Sensitivity and specificity for magnetic resonance imaging/real-time elastography fusion was 77.8% and 77.3% vs 74.1% and 62.9% for magnetic resonance imaging.

CONCLUSIONS

Magnetic resonance imaging/transrectal ultrasound fusion enhances the likelihood of detecting clinically significant cancers in a repeat biopsy setting. Adding real-time elastography to magnetic resonance imaging supports the characterization of cancer suspicious lesions.

Multiparametric magnetic resonance imaging (MRI) and subsequent MRI/ultrasonography fusion-guided biopsy increase the detection of anteriorly located prostate cancers

OBJECTIVE

To describe the detection rate of anteriorly located prostate cancer (PCa) with the addition of magnetic resonance imaging (MRI)/ultrasonography (US) fusion-guided biopsy (FGB) to the standard transrectal ultrasonography (TRUS)-guided biopsy.

PATIENTS AND METHODS

All patients, regardless of their biopsy history, who were referred for clinical suspicion of PCa (i.e elevated prostate-specific antigen (PSA) level and abnormal digital rectal examination) underwent 3T multiparametric-MRI (mpMRI) screening; and those with suspicious lesions in the anterior region of the prostate were identified. Patients then received a FGB of all suspicious lesions in addition to a systematic 12-core extended sextant TRUS-guided biopsy. We conducted a lesion-based analysis comparing cancer detection rates of anterior targets using FGB vs systematic cores taken from the same anatomic sextant within the prostate. Lengths of cancer in the most involved core were also compared between the two biopsy techniques used. Patients with only anterior targets were analysed separately.

RESULTS

Of 499 patients undergoing FGB, 162 had a total of 241 anterior lesions. The mean age, PSA level and prostate volume in this group were 62 years, 12.7 ng/dL, and 57 mL, respectively. In total, PCa was diagnosed in 121 anterior lesions (50.2%) identified on mpMRI. Sixty-two (25.7%) of these anterior lesions were documented as positive for cancer on systematic 12-core TRUS-guided biopsy cores, while 97 (40.2%) were positive on the targeted FGB cores (P = 0.001). In lesions that were positive on both FGB and TRUS biopsy, the most involved core was 112% longer on FGB (3.7 vs 1.6 mm, P ≤ 0.01). Forty-two patients had only anterior lesions on mpMRI; of these, 24 (57.1%) were found to have cancer on the FGB + TRUS biopsy platform. Six patients were positive on FGB only and 13 were positive on both biopsy techniques; however, 7/13 patients were upgraded to a higher Gleason score after FGB. All five patients positive on TRUS biopsy only were candidates for active surveillance.

CONCLUSION

The results showed that FGB detects significantly more anteriorly located PCa than does TRUS-guided biopsy alone and it may serve as an effective tool for the subset of patients with such tumours.

Patterns of repeat prostate biopsy in contemporary clinical practice

PURPOSE

The objectives of this study were to 1) describe the patterns of repeat prostate biopsy in men with a previous negative biopsy and 2) identify predictors of prostate cancer diagnosis on repeat biopsy in these men.

MATERIALS AND METHODS

From a university faculty group practice we identified 1,837 men who underwent prostate biopsy between January 1, 1995 and January 1, 2010. Characteristics of repeat biopsy were examined, including the indication for biopsy, the number of repeat biopsies performed, the number of cores obtained and total prostate specific antigen before biopsy. Features of prostate cancer diagnosed on repeat biopsy were examined, including Gleason score, number of positive cores, percent of tumor and treatment choice. Multivariable logistic regression was done to identify prostate cancer predictors.

RESULTS

Initial biopsy was negative in 1,213 men. In 255 men a total of 798 repeat biopsies were performed. Of the 63 men diagnosed with prostate cancer Gleason score was 6 or less in 33 (52%), 7 in 22 (35%) and 8-9 in 8 (13%). When categorized by Epstein criteria, the rate of clinically insignificant cancer diagnosis decreased substantially by the third and fourth repeat biopsies. Repeat biopsy in men older than 70 years, biopsies including more than 20 cores and the fourth repeat biopsy were associated with an increased likelihood of prostate cancer diagnosis.

CONCLUSIONS

In men selected for multiple repeat biopsies clinically significant cancer is found at each sampling round. Given the continued likelihood of cancer detection even by the fifth biopsy, early consideration of saturation or image guided biopsy may be warranted in the repeat biopsy population.

Magnetic resonance imaging-directed transperineal limited-mapping prostatic biopsies to diagnose prostate cancer: a Scottish experience

BACKGROUND

Transperineal prostatic biopsy is firmly established as an important tool in the diagnosis of prostate cancer. The benefit of additional imaging (magnetic resonance imaging) to target biopsy remains to be fully addressed.

METHODS

Using a cohort of consecutive patients undergoing transperineal template mapping biopsies, we studied positive biopsies in the context of magnetic resonance imaging findings and examined the accuracy of magnetic resonance imaging in predicting the location of transperineal template mapping biopsies-detected prostate cancer.

RESULTS

Forty-four patients (mean age: 65 years, range 53-78) underwent transperineal template mapping biopsies. Thirty-four patients had 1-2 and 10 patients had ≥3 previous transrectal ultrasound scan-guided biopsies. The mean prostate-specific antigen was 15 ng/mL (range 2.5-79 ng/mL). High-grade prostatic intraepithelial neoplasia was found in 12 (27%) patients and prostate cancer with Gleason <7, 7 and >7 in 13, 10 and 8 patients, respectively. Suspicious lesions on magnetic resonance imaging scans were scored from 1 to 5. In 28 patients, magnetic resonance imaging detected lesions with score ≥3. Magnetic resonance imaging correctly localised transperineal template mapping biopsies-detected prostate cancer in a hemi-gland approach, particularly in a right to left manner (79% positive prediction rate), but not in a quadrant approach (33% positive prediction rate).

CONCLUSION

Our findings support the notion of magnetic resonance imaging-based selection of patients for transperineal template mapping biopsies and that lesions revealed by magnetic resonance imaging are likely useful for targeted biopsies.

Are active surveillance criteria sufficient for predicting advanced stage prostate cancer patients?

OBJECTIVES

To examine the treatment outcomes of the prostate cancer (PCa) patients treated by radical prostatectomy (RP) who could be good candidates for active surveillance (AS) and test the confidence and reliability of the AS criterias for predicting advanced stage disease (RP Gleason score≥7 or Pathological stage T3).

METHODS

Between 2005 and 2012 the records of the 401 patients who underwent RP with a diagnosis of PCa were examined. Of these patients, 173 were found to be candidates of AS. The inclusion criteria were as follows; clinical stage T2a or less, PSA<10ng/ml, 2 or fewer cores involved with cancer, no single core with 50% or greater maximum involvement of cancer, and no Gleason grade greater than 3 in the specimen.

RESULTS

Univariate analyzes revealed that patients with advanced stage disease have higher prostate specific antigen density (PSAD), higher maximum percent (max%) in positive cores and higher RP tumor volumes. In multivariate analyzes PSAD, max% in positive cores and RP tumor volumes were statistically significant determinants for advanced stage disease. ROC analyzes revealed that the RP tumor volume is a good test on advanced stage disease.

CONCLUSIONS

Decreasing the cutoff values for PSAD and max% in positive cores should be considered for AS inclusion criteria. If we could calculate the tumor volume before RP, we can minimize the treatment failures (over or undertreatment) of PCa. Perhaps new biopsy protocols, tissue biomarkers, and molecular imaging technology may refine AS criteria.

[Prostate cancer of unknown primary origin with multiple lymph nodes metastasis; a case report]

A 62-year-old man were referred our hospital complaining of high prostate specific antigen (PSA) value (32.4 ng/ml) in May 2010. Two sets of biopsies preformed previously at another hospital had not detected any cancers in the prostate. In our hospital, prostate biopsies were performed in July 2010 and February 2011, but cancer was not detected in either occasion. In March 2011, his PSA increased up to 126.7 ng/ml, CT scan showed the swelling of left supraclavicular and para-aortic lymph nodes. Biopsy of the supraclavicular lymph node was performed. Pathology revealed poorly differentiated adenocarcinoma with positive immunohistochemistry for PSA, which was suggestive of metastatic prostate cancer. After 1 year of treatment with androgen deprivation therapy, the patient developed castration resistant prostate cancer and have undergone chemotherapy with docetaxel.

Multiparametric magnetic resonance imaging of the prostate: technical aspects and role in clinical management

The heterogeneity and largely indolent nature of prostate cancer require better tools to avoid overdetection of low-risk disease and improve diagnostic accuracy in high-risk patients. During the last 3 decades, magnetic resonance imaging (MRI) has evolved to become the most accurate imaging technique for prostate cancer detection and staging, with a promising role in risk stratification. Because each MRI technique has advantages and limitations, state of the art of the so-called multiparametric MRI of the prostate is achieved combining anatomical T2-weighted imaging integrated with other techniques in which image contrast is related to the pathophysiology of the disease, such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. After reviewing this article, readers will understand the clinical challenges in the management of patients with confirmed or suspected prostate cancer, when and how multiparametric MRI of the prostate can provide meaningful information, and how to perform and interpret it.

Comparison of transperineal mapping biopsy results with whole-mount radical prostatectomy pathology in patients with localized prostate cancer

Objective. We sought to evaluate the accuracy of transperineal mapping biopsy (TMB) by comparing it to the pathology specimen of patients who underwent radical prostatectomy (RP) for localized prostate cancer. Methods. From March 2007 to September 2009, 78 men at a single center underwent TMB; 17 of 78 subsequently underwent RP. TMB cores were grouped into four quadrants and matched to data from RP whole-mount slides. Gleason score, tumor location and volume, cross-sectional area, and maximal diameter were measured; sensitivity and specificity were assessed. Results. For the 17 patients who underwent RP, TMB revealed 12 (71%) had biopsy Gleason grades ≥ 3 + 4 and 13 (76%) had bilateral disease. RP specimens showed 14 (82%) had Gleason scores ≥ 3 + 4 and 13 (76%) had bilateral disease. Sensitivity and specificity of TMB for prostate cancer detection were 86% (95% confidence interval [CI] 72%-94%) and 83% (95% CI 62%-95%), respectively. Four quadrants negative for cancer on TMB were positive on prostatectomy, and six positive on TMB were negative on prostatectomy. Conclusion. TMB is a highly invasive procedure that can accurately detect and localize prostate cancer. These findings help establish baseline performance characteristics for TMB and its utility for organ-sparing strategies.

The value of magnetic resonance imaging in the detection of prostate cancer in patients with previous negative biopsies and elevated prostate-specific antigen levels: a meta-analysis

RATIONALE AND OBJECTIVES

To assess the diagnostic performance of magnetic resonance imaging (MRI) for targeting prostate cancer in patients with previous negative biopsies and elevated prostate-specific antigen (PSA) levels.

MATERIALS AND METHODS

Pubmed, Scopus, and Cochrane Library databases were searched to identify suitable studies published from January 2001 to October 2013. Polled estimation and subgroup analysis data were obtained using a random effect model. Summary receiver operating characteristic curves were used to summarize overall test performance.

RESULTS

Fourteen studies involving 698 patients met the included criteria. The mean prostate cancer detection rate was 37.5%. Twelve studies had a pooled sensitivity, specificity, and diagnostic odds ratio (DOR) of 88%, 69%, and 16.84 by patient analysis, respectively. In the subgroup analysis, magnetic resonance imaging spectroscopy (MRSI) provided higher pooled sensitivity (91%) and specificity (69%) compared with T2-weighted imaging (T2WI). MRSI combined with MRI had the highest pooled specificity (73%). By site analysis, the pooled sensitivity, specificity, and DOR in nine studies were 57%, 90%, and 14.34, respectively. In the subgroup analysis, MRSI combined with MRI showed higher pooled sensitivity (58%) and specificity (93%) compared with T2WI. Diffusion-weighted MRI (DWI) showed the highest pooled specificity: 95% but the lowest pooled sensitivity: 38%.

CONCLUSIONS

A limited number of studies suggest that the value of MRI to target prostate cancer in patients with previous negative biopsies and elevated PSA levels appears significant. MRI combined with MRSI is particularly accurate. Further studies are necessary to confirm the eventual role of DWI in this field.

Can we deliver randomized trials of focal therapy in prostate cancer?

Tissue-preserving focal therapies, such as brachytherapy, cryotherapy, high-intensity focused ultrasound and photodynamic therapy, aim to target individual cancer lesions rather than the whole prostate. These treatments have emerged as potential interventions for localized prostate cancer to reduce treatment-related adverse-effects associated with whole-gland treatments, such as radical prostatectomy and radiotherapy. In this article, the Prostate Cancer RCT Consensus Group propose that a novel cohort-embedded randomized controlled trial (RCT) would provide a means to study men with clinically significant localized disease, which we defined on the basis of PSA level (≤ 15 ng/ml or ≤ 20 ng/ml), Gleason grade (Gleason pattern ≤ 4 + 4 or ≤ 4 + 3) and stage (≤ cT2cN0M0). This RCT should recruit men who stand to benefit from treatment, with the control arm being whole-gland surgery or radiotherapy. Composite outcomes measuring rates of local and systemic salvage therapies at 3-5 years might best constitute the basis of the primary outcome on which to change practice.

Gene expression profiles in prostate cancer: identification of candidate non-invasive diagnostic markers

OBJECTIVE

To analyze gene expression profiles of prostate cancer (PCa) with the aim of determining the relevant differentially expressed genes and subsequently ascertain whether this differential expression is maintained in post-prostatic massage (PPM) urine samples.

MATERIAL AND METHODS

Forty-six tissue specimens (36 from PCa patients and 10 controls) and 158 urine PPM-urines (113 from PCa patients and 45 controls) were collected between December 2003 and May 2007. DNA microarrays were used to identify genes differentially expressed between tumour and control samples. Ten genes were technically validated in the same tissue samples by quantitative RT-PCR (RT-qPCR). Forty two selected differentially expressed genes were validated in an independent set of PPM-urines by qRT-PCR.

RESULTS

Multidimensional scaling plot according to the expression of all the microarray genes showed a clear distinction between control and tumour samples. A total of 1047 differentially expressed genes (FDR≤.1) were indentified between both groups of samples. We found a high correlation in the comparison of microarray and RT-qPCR gene expression levels (r=.928, P<.001). Thirteen genes maintained the same fold change direction when analyzed in PPM-urine samples and in four of them (HOXC6, PCA3, PDK4 and TMPRSS2-ERG), these differences were statistically significant (P<.05).

CONCLUSION

The analysis of PCa by DNA microarrays provides new putative mRNA markers for PCa diagnosis that, with caution, can be extrapolated to PPM-urines.