What Is the Negative Predictive Value of Multiparametric Magnetic Resonance Imaging in Excluding Prostate Cancer at Biopsy? A Systematic Review and Meta-analysis from the European Association of Urology Prostate Cancer Guidelines Panel

[TMPRSS2-Erg/AR-V7: Prognostic value of tests in urine and biopsy rince material in prostate cancer]

INTRODUCTION

Nowadays, diagnostic biomarker research is oriented on a genomic characterisation of prostate cancer (PCa). This study evaluated diagnostic values of TMPRSS2-Erg fusion transcripts expression (TE) and androgen receptor variant 7 (AR-V7) on urine (tU) and biopsic rince material (tLRB) samples.

MATERIALS AND METHODS

TE and AR-V7 have been tested by RT-PCR and RT-qPCR on urine and biopsies' rince liquid on 372 patients referred for prostate biopsies.

RESULTS

Two hundred thirty-three patients (62%) were diagnosed with PCa. tU.AR-V7 was positive for 15 healthy patients (28%) and 30 patients diagnosed with PCa (37%). tLRB.AR-V7 was positive for 66 patients (42%) diagnosed with PCa. Concerning TE for patients diagnosed with PCa, tU was positive for 59 patients (54%) and tLRB for 132 (55%). TE and TE/AR-V7 combination were significantly associated with PCa (P<0.001), as tLRB.AR-V7 (P<0.001). Sensitivity and specificity for TE/AR-V7 combination for PCa were respectively: tU.TE/AR-V7 67% and 70%, tLRB.TE/AR-V7 68.8% and 71%, and, tUtLRB.TE/AR-V7 83% and 60%. There was no benefit for AR-V7 and TE association versus TE alone when comparing AUC.

CONCLUSION

AR-V7 is not specific of PCa because of detection on healthy patients. This study did not managed to show a sufficient diagnostic value for TE/AR-V7 combination on urine and biospic rince material tests.

LEVEL OF EVIDENCE

3.

All change in the prostate cancer diagnostic pathway

Following detection of high levels of serum prostate-specific antigen, many men are advised to have transrectal ultrasound-guided biopsy in an attempt to locate a cancer. This nontargeted approach lacks accuracy and carries a small risk of potentially life-threatening sepsis. Worse still, it can detect clinically insignificant cancer cells, which are unlikely to be the origin of advanced-stage disease. The detection of these indolent cancer cells has led to overdiagnosis, one of the major problems of contemporary medicine, whereby many men with clinically insignificant disease are advised to undergo unnecessary radical surgery or radiotherapy. Advances in imaging and biomarker discovery have led to a revolution in prostate cancer diagnosis, and nontargeted prostate biopsies should become obsolete. In this Perspective article, we describe the current diagnostic pathway for prostate cancer, which relies on nontargeted biopsies, and the problems linked to this pathway. We then discuss the utility of prebiopsy multiparametric MRI and novel tumour markers. Finally, we comment on how the incorporation of these advances into a new diagnostic pathway will affect the current risk-stratification system and explore future challenges.

Contrast-enhanced ultrasound with dispersion analysis for the localization of prostate cancer: correlation with radical prostatectomy specimens

PURPOSE

To determine the value of two-dimensional (2D) contrast-enhanced ultrasound (CEUS) imaging and the additional value of contrast ultrasound dispersion imaging (CUDI) for the localization of clinically significant prostate cancer (csPCa).

METHODS

In this multicentre study, subjects scheduled for a radical prostatectomy underwent 2D CEUS imaging preoperatively. CUDI maps were generated from the CEUS recordings. Both CEUS recordings and CUDI maps were scored on the likelihood of presenting csPCa (any Gleason ≥ 4 + 3 and Gleason 3 + 4 larger than 0.5 mL) by five observers and compared to radical prostatectomy histopathology. An automated three-dimensional (3D) fusion protocol was used to match imaging with histopathology. Receiver operator curve (ROC) analysis was performed per observer and imaging modality.

RESULTS

133 of 216 (62%) patients were included in the final analysis. Average area under the ROC for all five readers for CEUS, CUDI and the combination was 0.78, 0.79 and 0.78, respectively. This yields a sensitivity and specificity of 81 and 64% for CEUS, 83 and 56% for CUDI and 83 and 55% for the combination. Interobserver agreement for CEUS, CUDI and the combination showed kappa values of 0.20, 0.18 and 0.18 respectively.

CONCLUSION

The sensitivity and specificity of 2D CEUS and CUDI for csPCa localization are moderate. Despite compressing CEUS in one image, CUDI showed a similar performance to 2D CEUS. With a sensitivity of 83% at cutoff point 3, it could become a useful imaging procedure, especially with 4D acquisition, improved quantification and combination with other US imaging techniques such as elastography.

Focal therapy for localized prostate cancer in the era of routine multi-parametric MRI

BACKGROUND

Prostate cancer focal therapy aims to minimize the side-effects of whole gland treatments, such as radical prostatectomy and radiotherapy without compromising oncological efficacy. However, concerns exist regarding the multifocal nature of prostate cancer and the lack of long-term oncological data for this form of treatment. In recent years, the routine adoption of multi-parametric magnetic resonance imaging (mpMRI) of the prostate has improved our ability to select candidates for focal therapy and to accurately deliver this form of prostate cancer treatment.

METHODS

We performed a review of the literature to provide a summary of the oncological and functional outcomes of men receiving primary prostate focal therapy. Furthermore, we discuss the impact of the routine implementation of mpMRI as part of the initial prostate cancer diagnostic pathway on the selection of candidates and delivery of focal therapy. Finally, we summarize knowledge gaps in the field and highlight active clinical trials in this arena.

RESULTS

Primary focal therapy involves the application of one of a number of energies that ablate tissue, such as cryotherapy and high intensity focused ultrasound (HIFU). Success is principally dependent on highly accurate patient selection and disease localization underpinned in large part by the routine integration of pre-biopsy mpMRI. Prospective medium-term follow-up data for primary HIFU and cryotherapy for men with intermediate-risk disease have shown acceptable cancer control with low risk of side effects and complications. Additional research is needed to clearly define an appropriate follow-up approach and to guide the management of in- and out-of-field recurrences. Multiple comparative trials with randomization against standard care are currently underway in men with intermediate- and high-risk prostate cancer.

CONCLUSION

The widespread adoption of prostate mpMRI has led to improved disease localization, enabling the performance of focal therapy as a viable treatment strategy for men with low volume intermediate-risk prostate cancer.

Institutional Adoption and Apprenticeship of Fusion Targeted Prostate Biopsy: Does Experience Affect the Cancer Detection Rate?

INTRODUCTION

There are limited data on the learning curve of magnetic resonance imaging/transrectal ultrasound (MRI/TRUS)-fusion targeted prostate biopsies (tBx).

OBJECTIVE

The aim of this study was to investigate the difference in prostate cancer (PCa) detection rate between an experienced urologist and novice resident performing tBx.

METHODS

A total of 183 patients underwent tBx from 2012 to 2016 for a total of 518 tBx cores. Biopsies in this study were performed by an experienced urologist (investigator A) or a novice resident (investigator B). The outcome was the detection of PCa on tBx. Using a multivariable logistic regression model, we estimated odds ratios for the detection of PCa. Inverse probability treatment weighting (IPTW) was used to balance patients' baseline characteristics and compare detection rates of PCa. Before performance of tBx, all patients underwent MRI.

RESULTS

On multivariable logistic regression analysis, investigator experience was associated with a higher odds of detection of PCa (OR = 1.003; 95% confidence interval 1.002-1.006, p = 0.037). After IPTW adjustment, there was no significant difference between the detection rate of investigator A (23%) and investigator B (32%; p = 0.457).

CONCLUSIONS

Data revealed a positive association between investigator experience and the odds of PCa detection, although there was no difference in the detection rates of the investigators.

Utility of digital rectal examination in a population with prostate cancer treated with active surveillance

INTRODUCTION

Digital rectal examination (DRE) is part of the clinical evaluation of men on active surveillance (AS). The purpose of the present study is to analyze the value of DRE as a predictor of upgrading in a population of men with prostate cancer (PCa) treated with AS.

METHODS

We used the prostate biopsy (PBx) database from an academic center, including PBx from 2006-2018, and identified 2029 confirmatory biopsies (CxPBx) of men treated with AS, of which 726 men had both diagnostic (initial) and CxPBx information available. We did a descriptive analysis and evaluated sensitivity, specificity, and predictive values of DRE for the detection of clinically significant PCa (csPCa). Multivariable regression analysis was done to identify predictors of csPCa. The primary outcome was to evaluate DRE as a predictor of the presence of csPCa at CxPBx.

RESULTS

Among the 2029 patients with a CxPBx, 75% had PCa, and of these, 30.3% had upgrading to International Society of Urologic Pathologists (ISUP) grade ≥2. Thirteen percent of men had a suspicious DRE (done by their treating physician). Sensitivity, specificity, negative and positive predictive values of DRE to detect csPCa were best with a prostate-specific antigen (PSA) <4 ng/ml (27%, 88%, 31%, and 87%, respectively). A suspicious DRE at CxPBx, particularly if the DRE at diagnosis was negative, was a predictor of csPCa (odds ratio [OR] 2.34, p=0.038). The main limitation of our study is the retrospective design and the lack of magnetic resonance imaging.

CONCLUSIONS

We believe DRE should still be used as part of AS and can predict the presence of csPCa, even with low PSA values. A suspicious nodule on DRE represents a higher risk of upgrading and should prompt further assessment.

Impact of biparametric prebiopsy prostate magnetic resonance imaging on the diagnostics of clinically significant prostate cancer in biopsy naïve men

Background: The objective of this study was to compare the prevalence of clinically significant prostate cancer (CSPCa) in men with biparametric prebiopsy prostate magnetic resonance imaging (MRI) and lesion-targeted biopsies (TBs) to the group of men without prebiopsy MRI in an initial biopsy session.Methods: The MRI group consists of men enrolled into four prospective clinical trials investigating a biparametric MRI (bpMRI) and TB while the non-MRI group was a retrospective cohort of men collected from an era prior to a clinical use of a prostate MRI. All men had standard biopsies (SBs). In the MRI group, men had additional TBs from potential cancer-suspicious lesions. CSPCa was defined as Gleason score ≥3 + 4 in any biopsy core taken. All the patients were prostate biopsy naïve.Results: The MRI group consists of 507 while the non-MRI group 379 men. Mean age and prostate specific antigen (PSA) level differed significantly (p < 0.05) between the groups: In the MRI group, 64 years and 7.6 ng/ml, respectively, and in the non-MRI group 68 years and 8.2 ng/ml, respectively. Significantly (p < 0.05) more CSPCa was diagnosed with initial biopsies in the MRI group (48%) compared to non-MRI group (34%). In men with no CSPCa diagnosed during the initial biopsies, significantly fewer (p < 0.05) men had upgrading re-biopsies in the MRI group (5%) than in the non-MRI group (19%) during the follow up.Conclusions: Prebiopsy bpMRI with TBs combined with SBs could lead to earlier diagnoses of CSPCa compared with men without prebiopsy prostate MRI used in initial PCa diagnostics.

Multiparametric MRI for prostate cancer diagnosis: current status and future directions

The current diagnostic pathway for prostate cancer has resulted in overdiagnosis and consequent overtreatment as well as underdiagnosis and missed diagnoses in many men. Multiparametric MRI (mpMRI) of the prostate has been identified as a test that could mitigate these diagnostic errors. The performance of mpMRI can vary depending on the population being studied, the execution of the MRI itself, the experience of the radiologist, whether additional biomarkers are considered and whether mpMRI-targeted biopsy is carried out alone or in addition to systematic biopsy. A number of challenges to implementation remain, such as ensuring high-quality execution and reporting of mpMRI and ensuring that this diagnostic pathway is cost-effective. Nevertheless, emerging clinical trial data support the adoption of this technology as part of the standard of care for the diagnosis of prostate cancer.

Accuracy of multiparametric magnetic resonance imaging for diagnosing prostate Cancer: a systematic review and meta-analysis

Background

The application of multiparametric magnetic resonance imaging (mpMRI) for diagnosis of prostate cancer has been recommended by the European Association of Urology (EAU), National Comprehensive Cancer Network (NCCN), and European Society of Urogenital Radiology (ESUR) guidelines. The purpose of this study is to systematically review the literature on assessing the accuracy of mpMRI in patients with suspicion of prostate cancer.

Method

We searched Embase, Pubmed and Cochrane online databases from January 12,000 to October 272,018 to extract articles exploring the possibilities that the pre-biopsy mpMRI can enhance the diagnosis accuracy of prostate cancer. The numbers of true- and false-negative results and true- and false-positive ones were extracted to calculate the corresponding sensitivity and specificity of mpMRI. Study quality was assessed using QUADAS-2 tool. Random effects meta-analysis and a hierarchical summary receiver operating characteristic (HSROC) plot were performed for further study.

Results

After searching, we acquired 3741 articles for reference, of which 29 studies with 8503 participants were eligible for inclusion. MpMRI maintained impressive diagnostic value, the area under the HSROC curve was 0.87 (95%CI,0.84–0.90). The sensitivity and specificity for mpMRI were 0.87 [95%CI, 0.81–0.91] and 0.68 [95%CI,0.56–0.79] respectively. The positive likelihood ratio was 2.73 [95%CI 1.90–3.90]; negative likelihood ratio was 0.19 [95% CI 0.14,-0.27]. The risk of publication bias was negligible with P = 0.96.

Conclusion

Results of the meta-analysis suggest that mpMRI is a sensitive tool to diagnose prostate cancer. However, because of the high heterogeneity existing among the included studies, further studies are needed to apply the results of this meta-analysis in clinic.

Are targeted prostate biopsies ready to replace systematic prostate biopsies?

OBJECTIVES

To evaluate the efficacy and efficiency of systematic prostatic biopsy (SPB) and cognitive fusion PB (CFPB) to diagnose prostate cancer (PCa) and significant PCa (SPCa), and to analyse if CFPB could safely replace SPB.

MATERIAL AND METHODS

A cohort of 314 consecutive men having PI-RADS ≥2 in a pre-biopsy 3T mp-MRI were prospectively subjected to trans-rectal ultrasound CFPB (two cores per suspicious area until a maximum of three areas) and a 12 peripheral core SPB. SPCa was considered when the WHO grade was higher than 2 (Gleason 4+3 or higher).

RESULTS

PCa was diagnosed in 133 patients (42.4%), being 83 (62.4%) SPCa. SPB detected PCa in 114 men (85.7%) while CFPB in 103 (77.4%), P<.001. SPB detected SPCa in 64 men (77.1%) while CFPB in 71 (85.5%), P<.001. In 52 of the 81 men (64.2%) SPCa was detected in SPB and CFPB. In 19 men SPCa was only detected in CFPB (23.5%) while in 10, it was only detected in SPB (12.3%). 33.1 cores were needed to diagnose one PCa in SPB while 8.5 in CFPB, P<.001. 58.9 cores were needed to diagnose one SPCa in SPB, while 12.4 in CFPB, P<.001.

CONCLUSIONS

CFPB are more effective and also more efficient than SPBs in detecting SPCa. However, CFPBs still can't safely replace SPBs because they are not able to detect up to 15% of SPCa.

Clinically significant Prostate Cancer diagnosed using a urinary molecular biomarker-based risk score: two case reports

BACKGROUND

Identifying men for a repeat prostate biopsy is a conundrum to urologists. Risk calculators (RCs) such as the European Randomized Study of Screening for Prostate Cancer (ERSPC) RCs have been developed to predict the outcome of prostate biopsies and have been shown to improve diagnostic accuracy compared to PSA alone. However, it was recently shown that the outcome for high-grade prostate cancer (PCa) upon biopsy tended to be underestimated in men with previous negative biopsies using ERSPC RC model 4. For these men, an individualized approach combining the clinical information with the outcome of biomarker-related urine tests may help to make a more informed decision.

CASE PRESENTATION

Two men, aged 66 and 69 respectively when presented in the clinic, show the typical dilemma of urologist and patient for electing repeat prostate biopsy. Both men had normal DRE findings, did not have a family history of PCa, presented with serum PSA values between 3 and 10 ng/ml and the first biopsies were negative for disease. The ERSPC RC4 did not indicate a biopsy in these men. The urinary molecular biomarker-based test for HOXC6 and DLX1, combining biomarker-expression profiling with clinical risk factors, resulted in SelectMDx Risk scores for these men that were higher than the cut-off of the test. Based on this outcome, mpMRI was performed with an outcome of PI-RADS ≥4 in both men. Histopathological evaluation of TRUS-guided biopsies confirmed high-grade PCa.

CONCLUSIONS

The urinary molecular biomarker-based risk score played a pivotal role in the diagnosis of clinically significant PCa whereas ERSPC RC4 outcome would not have indicated further diagnostic follow-up in these two cases. The timely diagnosis was shown to be crucial for the curative treatment by radical retropubic prostatectomy and the potential life-years gained for these two vital males.

Can the addition of clinical information improve the accuracy of PI-RADS version 2 for the diagnosis of clinically significant prostate cancer in positive MRI?

AIM

To report prostate cancer (PCa) prevalence in Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) categories and investigate the potential to avoid unnecessary, magnetic resonance imaging (MRI)-guided in-bore biopsies by adding clinical and biochemical patient characteristics.

MATERIALS AND METHODS

The present institutional review board-approved, prospective study on 137 consecutive men with 178 suspicious lesions on 3 T MRI was performed. Routine data collected for each patient included patient characteristics (age, prostate volume), clinical background information (prostate-specific antigen [PSA] levels, PSA density), and PI-RADS v2 scores assigned in a double-reading approach.

RESULTS

Histopathological evaluation revealed a total of 93/178 PCa (52.2%). The mean age was 66.3 years and PSA density was 0.24 ng/ml² (range, 0.04-0.89 ng/ml). Clinically significant PCa (csPCa, Gleason score >6) was confirmed in 50/93 (53.8%) lesions and was significantly associated with higher PI-RADS v2 scores (p=0.0044). On logistic regression analyses, age, PSA density, and PI-RADS v2 scores contributed independently to the diagnosis of csPCa (p=7.9×10^-7, p=0.097, and p=0.024, respectively). The resulting area under the receiver operating characteristic curve (AUC) to predict csPCa was 0.76 for PI-RADS v2, 0.59 for age, and 0.67 for PSA density. The combined regression model yielded an AUC of 0.84 for the diagnosis of csPCa and was significantly superior to each single parameter (p≤0.0009, respectively). Unnecessary biopsies could have been avoided in 50% (64/128) while only 4% (2/50) of csPCa lesions would have been missed.

CONCLUSIONS

Adding age and PSA density to PI-RADS v2 scores improves the diagnostic accuracy for csPCa. A combination of these variables with PI-RADS v2 can help to avoid unnecessary in-bore biopsies while still detecting the majority of csPCa.

PROSTATE CANCER DIAGNOSIS IN 2019 - CHANGES IN EUROPEAN GUIDELINES AND IMPACT ON DAILY PRACTICE

Changes in the diagnostic pathway for prostate cancer advised in the most recent Guidelines of the European Association of Urology bring many endeavors for everyday practice. Availability, costs and radiological expertise are still representing a challenge for the adoption of these guidelines in everyday clinical practice. In this article we discuss the current situation regarding these issues and future options.

Optimizing prostate biopsy techniques

PURPOSE OF REVIEW

Prostate cancer (PCa) diagnostics have undergone a number of changes as a result of efforts to reduce the detection rate of indolent prostate cancer and to increase the hit rate for clinically significant prostate cancer (csPCa). Here, we look at those studies that have shifted our knowledge and the impact these have had on clinical practice.

RECENT FINDINGS

The introduction of multiparametric MRI (mpMRI) and approaches to active surveillance have changed the landscape in prostate cancer diagnostics, reducing the number of men that need biopsy, but increasing the need for accuracy in mapping the extent of prostate cancer. As mpMRI reporting has become more accurate at predicting PCa, biopsy techniques have also evolved towards lesion (PI-RADS score 3-5) targeted biopsies. Uncertainty remains regarding the preferred approach to targeted biopsy, the need for systematic biopsies, and the place of software ultrasound/MRI fusion or in-bore MRI biopsy techniques versus 'cognitive' fusion techniques.

SUMMARY

Prostate biopsies remain essential for the diagnosis of PCa. But how best to do this? Latest guidelines advocate performing both targeted and systematic biopsies. Traditionally, prostate biopsies have been performed transrectally (TRUS) with hospital readmission rates of around 3% mainly because of infection. Additionally, TRUS prostate biopsies can miss anterior prostatic lesions. The transperineal approach addresses both these issues, but has historically required general anaesthetic such that adoption for front-line diagnostics is very difficult. Recent techniques to undertake transperineal biopsy under local anaesthetic have fundamentally changed this paradigm offering the genuine possibility that in 5 years' time, all front-line diagnostic biopsies will be performed as LATP.

Optimising prostate mpMRI: prepare for success

Multiparametric magnetic resonance imaging (MRI) now plays an essential role in prostate cancer diagnosis and management. The increasing use of MRI before biopsy makes obtaining images of the highest quality vital. The European Society of Urogenital Radiology (ESUR) 2012 guidelines and subsequent Prostate Imaging -Reporting Data System (PI-RADS) version 2 recommendations in 2015 address the technical considerations for optimising MRI acquisition; however, the quality of the multiparametric sequences employed depends not only on the hardware and software utilised and scanning parameters selected, but also on patient-related factors, for which current guidance is lacking. Patient preparation factors include bowel peristalsis, rectal distension, the presence of total hip replacement (THR), post-biopsy haemorrhage, and abstinence from ejaculation. New evidence has been accrued since the release of PI-RADS v2, and this review aims to explore the key issues of patient preparation and their potential to further optimise the image quality of mpMRI.

Performance and inter-observer variability of prostate MRI (PI-RADS version 2) outside high-volume centres

Objective: Despite the growing trend to embrace pre-biopsy MRI in the diagnostic pathway for prostate cancer (PC), its performance and inter-observer variability outside high-volume centres remains unknown. This study aims to evaluate sensitivity of and variability between readers of prostate MRI outside specialized units with radical prostatectomy (RP) specimen as the reference standard.Materials and methods: Retrospective study comprising a consecutive cohort of all 97 men who underwent MRI and subsequent RP between January 2012 and December 2014 at a private hospital in Sweden. Three readers, blinded to clinical data, reviewed all images (including 11 extra prostate MRI to reduce bias). A tumour was considered detected if the overall PI-RADS v2 score was 3-5 and there was an approximate match (same or neighbouring sector) of tumour sector according to a 24 sector system used for both MRI and whole mount sections.Results: Detection rate for the index tumour ranged from 67 to 76%, if PI-RADS 3-5 lesions were considered positive and 54-66% if only PI-RADS score 4-5 tumours were included. Detection rate for aggressive tumours (GS ≥ 4 + 3) was higher; 83.1% for PI-RADS 3-5 and 79.2% for PI-RADS 4-5. The agreement between readers showed average [Formula: see text] values of 0.41 for PI-RADS score 3-5 and 0.51 for PI-RADS score 4-5.Conclusions: Prostate MRI evidenced a moderate detection rate for clinically significant PC with a rather large variability between readers. Clinics outside specialized units must have knowledge of their performance of prostate MRI before considering omitting biopsies in men with negative MRI.

Developments in MRI-targeted prostate biopsy

PURPOSE OF REVIEW

MRI-targeted prostate biopsy may be an attractive alternative to systematic biopsy for diagnosing clinically significant prostate cancer. In this narrative review, we discuss the new developments that have occurred in the advancement of MRI-targeted prostate biopsy, over the past 24 months.

RECENT FINDINGS

MRI-targeted biopsy offers enhanced diagnostic accuracy, when compared with the current standard of care of systematic transrectal ultrasound-guided (TRUS) biopsy, by decreasing the overall number of biopsies needed, maintaining or improving significant prostate cancer detection, and reducing the detection of clinically insignificant prostate cancer. The necessity of combining systematic prostate biopsy with MRI-targeted biopsy is still debated. The use of MRI--ultrasound fusion systems for lesion-targeting is promising for optimizing significant cancer detection, but recent evidence suggests that additional cognitive biopsy cores are still useful in detecting additional cancers.

SUMMARY

MRI-targeted biopsy in selected men with positive MRI offers a number of benefits over systematic biopsy in all men, and as such, may emerge as the new standard of care for the diagnosis of clinically significant prostate cancer.

A Magnetic Resonance Imaging-Based Prediction Model for Prostate Biopsy Risk Stratification

Importance

Multiparametric magnetic resonance imaging (MRI) in conjunction with MRI-transrectal ultrasound (TRUS) fusion-guided biopsies have improved the detection of prostate cancer. It is unclear whether MRI itself adds additional value to multivariable prediction models based on clinical parameters.

Objective

To determine whether an MRI-based prediction model can reduce unnecessary biopsies in patients with suspected prostate cancer.

Design, Setting, and Participants

Patients underwent MRI, MRI-TRUS fusion-guided biopsy, and 12-core systematic biopsy in 1 session. The development cohort used to derive the prediction model consisted of 400 patients from 1 institution enrolled between May 14, 2015, and August 31, 2016, and the validation cohort included 251 patients from 2 independent institutions who underwent biopsies between April 1, 2013, and June 30, 2016, at 1 institution and between July 1, 2015, and October 31, 2016, at the other institution. The MRI model included MRI-derived parameters in addition to clinical variables. Area under the curve of receiver operating characteristic curves and decision curve analysis were performed.

Main Outcomes and Measures

Risk of clinically significant prostate cancer on biopsy, defined as a Gleason score of 3 + 4 or higher in at least 1 biopsy core.

Results

Overall, 193 (48.3%) of the 400 patients in the development cohort (mean [SD] age at biopsy, 64.3 [7.1] years) and 96 (38.2%) of the 251 patients in the validation cohort (mean [SD] age at biopsy, 64.9 [7.2] years) had clinically significant prostate cancer, defined as a Gleason score greater than or equal to 3 + 4. By applying the model to the external validation cohort, the area under the curve increased from 64% to 84% compared with the baseline model (P < .001). At a risk threshold of 20%, the MRI model had a lower false-positive rate than the baseline model (46% [95% CI, 32%-66%] vs 92% [95% CI, 70%-100%]), with only a small reduction in the true-positive rate (89% [95% CI, 85%-96%] vs 99% [95% CI, 89%-100%]). Eighteen of 100 fewer biopsies could have been performed, with no increase in the number of patients with missed clinically significant prostate cancers.

Conclusions and Relevance

The inclusion of MRI-derived parameters in a risk model could reduce the number of unnecessary biopsies while maintaining a high rate of diagnosis of clinically significant prostate cancers.

Magnetic Resonance Imaging-Guided Confirmatory Biopsy for Initiating Active Surveillance of Prostate Cancer

IMPORTANCE

Transrectal, ultrasonography-guided prostate biopsy often fails to disclose the severity of underlying pathologic findings for prostate cancer. Magnetic resonance imaging (MRI)-guided biopsy may improve the characterization of prostate pathologic results, but few studies have examined its use for the decision to enter active surveillance.

OBJECTIVE

To evaluate whether confirmatory biopsy findings by MRI guidance are associated with the risk of pathologic disease upgrading among patients with prostate cancer during active surveillance.

DESIGN, SETTINGS, AND PARTICIPANTS

This retrospective cohort study used prospectively obtained registry data from 332 men with prostate cancer of Gleason grade group (GG) 2 or lower who were referred for active surveillance at a large academic medical center from January 1, 2009, through December 31, 2017.

EXPOSURES

All confirmatory and follow-up biopsies were performed using MRI guidance with an MRI-ultrasonography fusion device. Patients underwent repeated MRI-guided biopsies every 12 to 24 months. At follow-up sessions, in addition to obtaining systematic samples, lesions seen on MRI were targeted and foci of low-grade prostate cancer were obtained again using tracking technology. Active surveillance was terminated with detection of at least GG3 disease or receipt of treatment.

MAIN OUTCOMES AND MEASURES

The primary outcome was upgrading to at least GG3 disease during active surveillance. Secondary outcomes were the associations of MRI lesion grade, prostate-specific antigen (PSA) level, PSA density, and biopsy method (targeted, systematic, or tracked) with the primary outcome.

RESULTS

Of 332 patients (mean [SD] age, 62.8 [7.6] years), 39 (11.7%) upgraded to at least GG3 disease during follow-up. The incidence of upgrading was 7.9% (9 of 114) when the confirmatory biopsy finding was normal, 11.4% (20 of 175) when the finding showed GG1 disease, and 23.3% (10 of 43) when the finding was GG2 disease (P = .03). Men with GG2 disease were almost 8 times more likely to upgrade during surveillance compared with those with normal findings but only among those with low PSA density (hazard ratio [HR], 7.82; 95% CI, 2.29-26.68). A PSA density of at least 0.15 ng/mL/mL was associated with increased risk of upgrading among patients with normal findings (HR, 7.21; 95% CI, 1.98-26.24) or GG1 disease (HR, 2.86; 95% CI, 1.16 to 7.03) on confirmatory biopsy. A total of 46% of pathologic disease upgrades would have been missed if only the targeted biopsy was performed and 65% of disease upgrades were detected only with tracked biopsy.

CONCLUSIONS AND RELEVANCE

The findings suggest that confirmatory biopsy with MRI guidance is significantly associated with future disease upgrading of prostate cancer, especially when combined with PSA density, and should be considered as an appropriate entry point for active surveillance. Systematic and targeted biopsies were additive in detection of clinically significant cancers. Repeated biopsy at sites at which findings were previously abnormal (tracking biopsy) facilitated detection of cancers not suitable for continued active surveillance.

Multimodality Imaging of Prostate Cancer

Prostate cancer is a very heterogeneous disease, and contemporary management is focused on identification and treatment of the prognostically adverse high-risk tumors while minimizing overtreatment of indolent, low-risk tumors. In recent years, imaging has gained increasing importance in the detection, staging, posttreatment assessment, and detection of recurrence of prostate cancer. Several imaging modalities including conventional and functional methods are used in different clinical scenarios with their very own advantages and limitations. This continuing medical education article provides an overview of available imaging modalities currently in use for prostate cancer followed by a more specific section on the value of these different imaging modalities in distinct clinical scenarios, ranging from initial diagnosis to advanced, metastatic castration-resistant prostate cancer. In addition to established imaging indications, we will highlight some potential future applications of contemporary imaging modalities in prostate cancer.

Comparing significant prostate cancer detection rates after the introduction of pre-biopsy MRI: turning PROMIS into action

Introduction:

Basingstoke was a participating centre in the MRC funded PROMIS trial between 2013 and 2015 recruiting 130 patients. In response to a perceived change in prostate biopsy histological grading following the introduction of pre-biopsy magnetic resonance imaging at our centre, we decided to undertake a retrospective analysis of prostate histology before and after participation in the study.

Methods:

We identified 206 patients in both 2012 and 2016 who had undergone prostate biopsy. We reviewed the type of biopsy performed (transrectal or transperineal), the number of cores sampled, the number of positive cores and the cancer grade. The proportion of men who had pre-biopsy multiparametric magnetic resonance imaging was also recorded.

Results:

Although the total numbers undergoing biopsy were equivalent in 2012 and 2016, 37% of all patients undergoing biopsy underwent a transperineal template biopsy in 2012, increasing to 54% in 2016. The overall percentage of positive biopsy results (Gleason score ⩾3+3) increased from 70% to 83.0% (χ2=9.83, P=0.002). While the number of grade group 1 cancers significantly decreased from 63.9% (2012) to 22% (2016), there was a corresponding increase in the number of grade group 3 or higher cancers detected from 11% to 51%. In 2012, 33% of patients had multiparametric magnetic resonance imaging prior to biopsy compared with 90% in 2016. The pre-biopsy magnetic resonance imaging improved the cancer detection rates for both methods of biopsy sampling.

Conclusion:

Our study has confirmed that the introduction of pre-biopsy multiparametric magnetic resonance imaging can improve diagnostic accuracy and reduce the number of insignificant cancers detected. This overall upgrading of the biopsied population, and the resulting shift towards detecting an increased number of significant cancers, is likely to have a positive impact on treatment allocation and longer-term outcomes for our patients. This effect should be reproducible in other centres.

Level of evidence:

Not applicable for this multicentre audit.

Personalizing prostate cancer diagnosis with multivariate risk prediction tools: how should prostate MRI be incorporated?

Risk-based patient selection for systematic biopsy in prostate cancer diagnosis has been adopted in daily clinical practice, either by clinical judgment and PSA testing, or using multivariate risk prediction tools. The use of multivariable risk prediction tools can significantly reduce unnecessary systematic biopsies, without compromising the detection of clinically significant disease. Increasingly multi-parametric magnetic resonance imaging (MRI) is performed, not only in men with a persistent suspicion of prostate cancer after prior negative systematic biopsy, but also at initial screening before the first biopsy. The combination of MRI and multivariate risk prediction tools could potentially enhance prostate cancer diagnosis using multivariate MRI incorporated risk-based models to decide on the need for prostate MRI, but also using MRI results to adjusted risk-based models, and to guide MRI-directed biopsies. In this review, we discuss the diagnostic work-up for clinically significant prostate cancer, where the combination of MRI and multivariate risk prediction tools is integrated, and how together they can contribute to personalized diagnosis.

Developing an effective strategy to improve the detection of significant prostate cancer by combining the 4Kscore and multiparametric MRI

OBJECTIVES

Recent years have seen the development of biomarkers and imaging technologies designed to improve the specificity of PSA. Widespread implementation of imaging technologies, such as mp-MRI raises considerable logistical challenges. Our objective was to evaluate a biopsy strategy that utilizes selective mp-MRI as a follow-up test to biomarkers to improve the detection of significant prostate cancer.

METHODS AND MATERIALS

We developed a conceptual approach based on the risk calculated from the 4Kscore using results from the US prospective validation study, multiplied by the likelihood ratio of mp-MRI from the PROMIS trial. The primary outcome was Gleason grade ≥ 7 (grade group ≥ 2) cancer on biopsy. Using decision curve analysis, the net benefit was determined for our model and compared with the use of the 4Kscore and mp-MRI independently at various thresholds for biopsy.

RESULTS

For a cut-point of 7.5% risk of high-grade disease, patients with <5% risk from a blood marker would not have risk of significant prostate cancer sufficiently increased by a positive mp-MRI to warrant biopsy; comparably, patients with a risk >23% would not have risk sufficiently reduced by a negative imaging study to forgo biopsy. From the 4Kscore validation study, 46% of men considered for biopsy in the US have risks 5% to 23%. Net benefit was highest for the combined strategy, followed by 4Kscore alone.

CONCLUSIONS

Selective mp-MRI in men with intermediate scores on a secondary blood test results in a biopsy strategy that is more scalable than mp-MRI for all men with elevated PSA. Prospective validation is required to demonstrate if the predicted properties of combined blood and imaging testing are empirically confirmed.

Optimising the number of cores for magnetic resonance imaging ‐guided targeted and systematic transperineal prostate biopsy

Objectives

To assess cancer detection rates of different target‐dependent transperineal magnetic resonance (MR)/ultrasonography (US) fusion‐guided biopsy templates with reduced number of systematic cores.

Patients and Methods

Single‐centre outcome of transperineal MR/US fusion‐guided biopsies of 487 men with a single target MR imaging (MRI) lesion, prospectively collected between 2012 and 2016. All men underwent transperineal targeted biopsy (TB) with two cores, followed by 18–24 systematic sector biopsies (SB) using the Ginsburg protocol. Gleason score ≥7 prostate cancer detection rates for two‐core TB, four‐core extended TB (eTB), 10‐ to 20‐core saturation TB (sTB) including cores from sectors adjacent to the target, and 14 core ipsilateral TB (iTB) were compared to combined TB+SB.

Results

Cancer was detected in 345 men and Gleason score 7–10 cancer in 211 men. TB alone detected 67%, eTB 76%, sTB 91% and iTB 91% of these Gleason score 7–10 cancers. In the subgroup of 33 men (7% of cohort) with an anterior >0.5 mL highly suspicious MRI lesion and a prostate volume ≤45 mL, four‐core eTB detected 31 of 32 cancers (97%) and all 26 Gleason score 7–10 cancers.

Conclusion

sTB detected Gleason score 7–10 cancer in 25% more of the men than a two‐core TB approach, and in almost as many men (91%) as the 20–26‐core combined TB+SB, while needing only 10–20 cores. A four‐core extended TB may suffice for large, highly suspicious anterior lesions in small or slightly enlarged prostates.

A comparison of magnetic resonance imaging techniques used to secure biopsies in prostate cancer patients

Introduction: Prostate cancer (PCa) is the most common diagnosed malignancy among the male population in the United States. The incidence is increasing with an estimated amount of 175.000 cases in 2019. Areas covered: Primarily, PCa is generally detected by an elevated or rising serum prostate-specific antigen (PSA) and digital rectal examination (DRE) followed by pathological examination. Histopathology ultimately confirms the presence of PCa and determines a Gleason score. However, PSA and DRE have low specificity and sensitivity, respectively. Subsequently, accurate assessment of the aggressiveness of PCa is essential to prevent overdiagnosis and thus overtreatment of low-risk or indolent cancers. By visualizing PCa suspicious lesions and sampling them during the targeted biopsy, it is likely that the diagnostic accuracy of significant PCa improves. This article reviews the current imaging techniques used to secure biopsies in patients with a suspicion of PCa. The advantages and limitations of each technique are described. Expert opinion: Multiparametric magnetic resonance imaging (mpMRI) and subsequent-targeted biopsy have improved the diagnostic accuracy of PCa detection in men with an elevated or rising serum PSA. Prostate lesions visible on mpMRI are easily targeted during either in-bore MRI-guided biopsy, cognitive fusion biopsy or MRI-TRUS fusion biopsy.

Performance of Combined Magnetic Resonance Imaging/Ultrasound Fusion-guided and Systematic Biopsy of the Prostate in Biopsy-naïve Patients and Patients with Prior Biopsies

BACKGROUND

As recent prospective studies showed targeted biopsies (TBs) to be superior to systematic biopsies (SBs), magnetic resonance imaging (MRI) is gaining wider acceptance in the diagnostic setup of prostate cancer (PCa).

OBJECTIVE

To examine the performance of MRI/ultrasound fusion-guided TB in combination with SB in the detection of PCa in patients with and without prior biopsy.

DESIGN, SETTING, AND PARTICIPANTS

A total of 219 men undergoing combined transrectal TB and 12-core SB from February 2014 to November 2018 were analysed. For all patients showing a suspicion of PCa in multiparametric MRI, TB was performed using fusion imaging with real-time virtual sonography.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cancer detection rates (CDRs) and significant CDRs for TB, SB, and TB+SB were analysed. Further stratification was performed for a number of previous biopsy sessions and Prostate Imaging Reporting and Data System (PI-RADS) score. Significant PCa was defined as any PCa with Gleason score ≥3+4.

RESULTS AND LIMITATIONS

Of all, 141 patients were biopsy naïve, while 78 patients had at least one prior biopsy. Median prostate-specific antigen (PSA) level prior to biopsy was 8.4ng/ml (interquartile range 5.5-11.8ng/ml). The overall CDR was 63.5% (139/219), while the PI-RADS-dependent CDRs for the combination of TB+SB were 29.1%, 67.7%, and 86.2% for patients with PI-RADS 3, 4, and 5, respectively. Looking at TB or SB alone, CDRs were 55.7% and 57.5%. The overall CDR for significant PCa was 51.6%. (18.2%, 50.5%, and 81.5% for PI-RADS 3, 4, and 5, respectively). CDRs were significantly higher for biopsy-naïve patients (65.2% vs 67.4% vs 71.6% for TB vs SB vs TB+SB) than for patients with one previous negative biopsy (38.2% vs 43.6% vs 50.9% for TB vs SB vs TB+SB; all p<0.01).

CONCLUSIONS

Multiparametric MRI can raise the CDR in patients with and without biopsies performed earlier. With higher PI-RADS lesions, the risk of harbouring PCa increases. Combining TB with SB further improved the diagnostic accuracy in biopsy-naïve patients and after one previous negative biopsy.

PATIENT SUMMARY

Multiparametric magnetic resonance imaging before prostate biopsy increases cancer detection rates in biopsy-naïve patients and patients with a previous negative biopsy. The combination of targeted biopsy with systematic biopsy improved the diagnostic accuracy in biopsy-naïve patients and after one previous negative biopsy.

Can DCE-MRI reduce the number of PI-RADS v.2 false positive findings? Role of quantitative pharmacokinetic parameters in prostate lesions characterization

PURPOSE

To test the potential impact of pharmacokinetic parameters, derived from DCE-MRI analysis, on the diagnostic performance of PI-RADSv.2 classification in prostate lesions characterization.

METHOD

Among patients who underwent multiparametric prostate MRI (mpMRI) (January 2016-March 2018) followed by histological evaluation (targeted biopsies/prostatectomy), 103 men were retrospectively selected. For each patient the index lesion was identified and pharmacokinetic parameters (Ktrans, Kep, Ve, Vp) were assessed. MRI diagnostic performance in the detection of significant tumors [Gleason Score (GS)≥7] was assessed, considering PI-RADS≥3 as positive.

RESULTS

GS ≥ 7 (n = 59) showed higher Ktrans (p < 0.01) and Kep (p = 0.01) compared to GS < 7. At ROC curve analysis, a Ktrans cut-off of 191 × 10^-3/min was identified to predict the presence of GS ≥ 7 (AUC:0.75; sensitivity:95%; specificity:61%). Sensitivity and PPV of mpMRI using PI-RADSv.2 were 98% and 61%. Reclassifying PI-RADS≥3 lesions according to Ktrans cut-off, 22 false positives were shifted to true negatives with 3 false negative findings; PPV raised to 79%. Appling Ktrans cut-off to PI-RADS 3 lesions of peripheral zone (n = 18), 12 true negatives, 4 true positives, 2 false positives were identified.

CONCLUSIONS

Despite its high sensitivity prostate mpMRI generates many false positive cases: Ktrans in addition to PIRADS v.2 seems to improve MRI-PPV and may help in avoiding redundant biopsies.

The First In Vivo Needle-Based Optical Coherence Tomography in Human Prostate: A Safety and Feasibility Study

OBJECTIVE

To demonstrate the safety and feasibility of clinical in vivo needle-based optical coherence tomography (OCT) imaging of the prostate.

MATERIALS AND METHODS

Two patients with prostate cancer underwent each two percutaneous in vivo needle-based OCT measurements before transperineal template mapping biopsy. The OCT probe was introduced via a needle and positioned under ultrasound guidance. To test the safety, adverse events were recorded during and after the procedure. To test the feasibility, OCT and US images were studied during and after the procedure. Corresponding regions for OCT and biopsy were determined. A uropathologist evaluated and annotated the histopathology. Three experts assessed all the corresponding OCT images. The OCT and biopsy conclusions for the corresponding regions were compared.

RESULTS

No adverse events during and following the, in total four, in vivo needle-based OCT measurements were reported. The OCT measurements showed images of prostatic tissue with a penetration depth of ~1.5 mm. The histological-proven tissue types, which were also found in the overlapping OCT images, were benign glands, stroma, glandular atrophy, and adenocarcinoma (Gleason pattern 3).

CONCLUSIONS

Clinical in vivo needle-based OCT of the prostate is feasible with no adverse events during measurements. OCT images displayed detailed prostatic tissue with a imaging depth up to ~1.5 mm. We could co-register four histological-proven tissue types with OCT images. The feasibility of in vivo OCT in the prostate opens the pathway to the next phase of needle-based OCT studies in the prostate. Lasers Surg. Med. 51:390-398, 2019. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

PI-RADS version 2.1: one small step for prostate MRI

Multiparametric (mp) prostate magnetic resonance imaging (MRI) is playing an increasingly prominent role in the diagnostic work-up of patients with suspected prostate cancer. Performing mpMRI before biopsy offers several advantages including biopsy avoidance under certain clinical circumstances and targeting biopsy of suspicious lesions to enable the correct diagnosis. The success of the technique is heavily dependent on high-quality image acquisition, interpretation, and report communication, all areas addressed by previous versions of the Prostate Imaging-Reporting and Data System (PI-RADS) recommendations. Numerous studies have validated the approach, but the widespread adoption of PI-RADS version 2 has also highlighted inconsistencies and limitations, particularly relating to interobserver variability for evaluation of the transition zone. These limitations are addressed in the recently released version 2.1. In this article, we highlight the key changes proposed in PI-RADS v2.1 and explore the background reasoning and evidence for the recommendations.

Comparison of Magnetic Resonance Imaging-stratified Clinical Pathways and Systematic Transrectal Ultrasound-guided Biopsy Pathway for the Detection of Clinically Significant Prostate Cancer: A Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Recent studies suggested that magnetic resonance imaging (MRI) followed by targeted biopsy ("MRI-stratified pathway") detects more clinically significant prostate cancers (csPCa) than the systematic transrectal ultrasound-guided prostate biopsy (TRUS-Bx) pathway, but controversy persists. Several randomized clinical trials (RCTs) were recently published, enabling generation of higher-level evidence to evaluate this hypothesis.

OBJECTIVE

To perform a systematic review and meta-analysis of RCTs comparing the detection rates of csPCa in the MRI-stratified pathway and the systematic TRUS-Bx pathway in patients with a suspicion of prostate cancer (PCa).

EVIDENCE ACQUISITION

PubMed, EMBASE, and Cochrane databases were searched up to March 18, 2019. RCTs reporting csPCa detection rates of both pathways in patients with a clinical suspicion of prostate cancer were included. Relative csPCa detection rates of the MRI-stratified pathway were pooled using random-effect model. Study quality was assessed using the Cochrane risk of bias tool for randomized trials. A comparison of detection rates of clinically insignificant PCa (cisPCa) and any PCa was also performed.

EVIDENCE SYNTHESIS

Nine RCTs (2908 patients) were included. The MRI-stratified pathway detected more csPCa than the TRUS-Bx pathway (relative detection rate 1.45 [95% confidence interval {CI} 1.09-1.92] for all patients, and 1.42 [95% CI 1.02-1.97] and 1.60 [95% CI 1.01-2.54] for biopsy-naïve and prior negative biopsy patients, respectively). Detection rates were not significantly different between pathways for cisPCa (0.89 [95% CI 0.49-1.62]), but higher in the MRI-stratified pathway for the detection of any PCa (1.39 [95% CI 1.05-1.84]).

CONCLUSIONS

The MRI-stratified pathway detected more csPCa than the systematic TRUS-guided biopsy pathway in men with a clinical suspicion of PCa, for both biopsy-naïve patients and those with prior negative biopsy. The detection rate of any PCa was higher in the MRI-stratified pathway, but not significantly different from that of cisPCa.

PATIENT SUMMARY

Our meta-analysis of clinical trials shows that the magnetic resonance imaging-stratified pathway detects more clinically significant prostate cancers than the transrectal ultrasound-guided prostate biopsy pathway in men with a suspicion of prostate cancer.

PI-RADS Steering Committee: The PI-RADS Multiparametric MRI and MRI-directed Biopsy Pathway

High-quality evidence shows that MRI in biopsy-naive men can reduce the number of men who need prostate biopsy and can reduce the number of diagnoses of clinically insignificant cancers that are unlikely to cause harm. In men with prior negative biopsy results who remain under persistent suspicion, MRI improves the detection and localization of life-threatening prostate cancer with greater clinical utility than the current standard of care, systematic transrectal US-guided biopsy. Systematic analyses show that MRI-directed biopsy increases the effectiveness of the prostate cancer diagnosis pathway. The incorporation of MRI-directed pathways into clinical care guidelines in prostate cancer detection has begun. The widespread adoption of the Prostate Imaging Reporting and Data System (PI-RADS) for multiparametric MRI data acquisition, interpretation, and reporting has promoted these changes in practice. The PI-RADS MRI-directed biopsy pathway enables the delivery of key diagnostic benefits to men suspected of having cancer based on clinical suspicion. Herein, the PI-RADS Steering Committee discusses how the MRI pathway should be incorporated into routine clinical practice and the challenges in delivering the positive health impacts needed by men suspected of having clinically significant prostate cancer.

The primacy of multiparametric MRI in men with suspected prostate cancer

Background

Multiparametric MRI (mpMRI) became recognised in investigating those with suspected prostate cancer between 2010 and 2012; in the USA, the preventative task force moratorium on PSA screening was a strong catalyst. In a few short years, it has been adopted into daily urological and oncological practice. The pace of clinical uptake, born along by countless papers proclaiming high accuracy in detecting clinically significant prostate cancer, has sparked much debate about the timing of mpMRI within the traditional biopsy-driven clinical pathways. There are strongly held opposing views on using mpMRI as a triage test regarding the need for biopsy and/or guiding the biopsy pattern.

Objective

To review the evidence base and present a position paper on the role of mpMRI in the diagnosis and management of prostate cancer.

Methods

A subgroup of experts from the ESUR Prostate MRI Working Group conducted literature review and face to face and electronic exchanges to draw up a position statement.

Results

This paper considers diagnostic strategies for clinically significant prostate cancer; current national and international guidance; the impact of pre-biopsy mpMRI in detection of clinically significant and clinically insignificant neoplasms; the impact of pre-biopsy mpMRI on biopsy strategies and targeting; the notion of mpMRI within a wider risk evaluation on a patient by patient basis; the problems that beset mpMRI including inter-observer variability.

Conclusions

The paper concludes with a set of suggestions for using mpMRI to influence who to biopsy and who not to biopsy at diagnosis.

Key Points

• Adopt mpMRI as the first, and primary, investigation in the workup of men with suspected prostate cancer.

• PI-RADS assessment categories 1 and 2 have a high negative predictive value in excluding significant disease, and systematic biopsy may be postponed, especially in men with low-risk of disease following additional risk stratification.

• PI-RADS assessment category lesions 4 and 5 should be targeted; PI-RADS assessment category lesion 3 may be biopsied as a target, as part of systematic biopsies or may be observed depending on risk stratification.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06166-z) contains supplementary material, which is available to authorized users.

Validation of IMPROD biparametric MRI in men with clinically suspected prostate cancer: A prospective multi-institutional trial

BACKGROUND

Magnetic resonance imaging (MRI) combined with targeted biopsy (TB) is increasingly used in men with clinically suspected prostate cancer (PCa), but the long acquisition times, high costs, and inter-center/reader variability of routine multiparametric prostate MRI limit its wider adoption.

METHODS AND FINDINGS

The aim was to validate a previously developed unique MRI acquisition and reporting protocol, IMPROD biparametric MRI (bpMRI) (NCT01864135), in men with a clinical suspicion of PCa in a multi-institutional trial (NCT02241122). IMPROD bpMRI has average acquisition time of 15 minutes (no endorectal coil, no intravenous contrast use) and consists of T2-weighted imaging and 3 separate diffusion-weighed imaging acquisitions. Between February 1, 2015, and March 31, 2017, 364 men with a clinical suspicion of PCa were enrolled at 4 institutions in Finland. Men with an equivocal to high suspicion (IMPROD bpMRI Likert score 3-5) of PCa had 2 TBs of up to 2 lesions followed by a systematic biopsy (SB). Men with a low to very low suspicion (IMPROD bpMRI Likert score 1-2) had only SB. All data and protocols are freely available. The primary outcome of the trial was diagnostic accuracy-including overall accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value-of IMPROD bpMRI for clinically significant PCa (SPCa), which was defined as a Gleason score ≥ 3 + 4 (Gleason grade group 2 or higher). In total, 338 (338/364, 93%) prospectively enrolled men completed the trial. The accuracy and NPV of IMPROD bpMRI for SPCa were 70% (113/161) and 95% (71/75) (95% CI 87%-98%), respectively. Restricting the biopsy to men with equivocal to highly suspicious IMPROD bpMRI findings would have resulted in a 22% (75/338) reduction in the number of men undergoing biopsy while missing 4 (3%, 4/146) men with SPCa. The main limitation is uncertainty about the true PCa prevalence in the study cohort, since some of the men may have PCa despite having negative biopsy findings.

CONCLUSIONS

IMPROD bpMRI demonstrated a high NPV for SPCa in men with a clinical suspicion of PCa in this prospective multi-institutional clinical trial.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02241122.

Can We Improve the Preoperative Prediction of Prostate Cancer Recurrence With Multiparametric MRI?

INTRODUCTION

The use of multiparametric magnetic resonance imaging (mpMRI) to assess prostate cancer (PCa) has increased over the past decade. We aimed to assess if preoperative mpMRI lesion score, a variable routinely available for men undergoing pre-biopsy MRI, improves the performance of commonly used preoperative predictive models for PCa recurrence.

PATIENTS AND METHODS

We analyzed data from 372 patients with PCa treated with radical prostatectomy in 2012 to 2017 and assessed with pre-biopsy mpMRI within 6 months prior to surgery. Suspicious areas for cancer were scored on a standardized 5-point scale. Cox regression was used to assess the association between mpMRI score and the risk of postoperative biochemical recurrence. Two different models were tested accounting for factors included in the Kattan nomogram and in the D'Amico risk-classification.

RESULTS

Overall, 53% and 30% of patients were found with a lesion scored 4 or 5 at pre-biopsy mpMRI, respectively. Risk varied widely by mpMRI (29% 2-year risk of biochemical recurrence for a score of 5 vs. 5% for a score of 1-2), and mpMRI score was associated with large hazard ratios after adjusting for stage, grade, and prostate-specific antigen: 1.66, 1.96, and 2.71 for scores 3, 4, and 5, respectively. However, 95% confidence intervals were very wide (0.19-14.20, 0.26-14.65, and 0.36-20.55, respectively) and included 1.

CONCLUSIONS

Our data did not show that preoperative models, commonly used to assess PCa risk, were improved after including the pre-biopsy mpMRI score. However, the value of pre-biopsy mpMRI to improve preoperative risk models should be investigated in larger data sets.

Improved detection and reduced biopsies: the effect of a multiparametric magnetic resonance imaging-based triage prostate cancer pathway in a public teaching hospital

PURPOSE

Multiparametric magnetic resonance imaging (mpMRI) improves clinically significant prostate cancer (csPCa) detection by facilitating targeted biopsy (cognitive, fusion technology, or in-gantry MRI guidance) and reducing negative biopsies. This study sought to describe the feasibility of introducing an mpMRI-based triage pathway, including diagnostic performance, applicability to training, and cost analysis.

METHODS

An observational retrospective cohort study of consecutive patients attending a large public tertiary referral training hospital who underwent mpMRI for suspicion of prostate cancer was considered. Standard clinical, MRI-related, histopathological, and financial parameters were collected for analysis of biopsy avoidance, diagnostic accuracy of biopsy approach, and operator (consultant and resident/registrar) and logistical (including financial) feasibility.

RESULTS

653 men underwent mpMRI, of which 344 underwent prostate biopsy resulting in a 47% biopsy avoidance rate. Overall, 240 (69.8%) patients were diagnosed with PCa, of which 208 (60.5%) were clinically significant, with higher rates of csPCa observed for higher PIRADS scores. In patients who underwent both systematic and targeted biopsy (stTPB), targeted cores detected csPCa in 12.7% and 16.6% in more men than systematic cores in PIRADS 5 and 4, respectively, whereas systematic cores detected csPCa in 5% and 3.2% of patients, where targeted cores did not. A high standard of performance was maintained across the study period and the approach was shown to be cost effective.

CONCLUSIONS

Introdution of an mpMRI-based triage system into a large public tertiary teaching hospital is feasible, cost effective and leads to high rates of prostate cancer diagnosis while reducing unnecessary biopsies and detection of insignificant PCa.

Prostate MRI, with or without MRI-targeted biopsy, and systematic biopsy for detecting prostate cancer

BACKGROUND

Multiparametric magnetic resonance imaging (MRI), with or without MRI-targeted biopsy, is an alternative test to systematic transrectal ultrasonography-guided biopsy in men suspected of having prostate cancer. At present, evidence on which test to use is insufficient to inform detailed evidence-based decision-making.

OBJECTIVES

To determine the diagnostic accuracy of the index tests MRI only, MRI-targeted biopsy, the MRI pathway (MRI with or without MRI-targeted biopsy) and systematic biopsy as compared to template-guided biopsy as the reference standard in detecting clinically significant prostate cancer as the target condition, defined as International Society of Urological Pathology (ISUP) grade 2 or higher. Secondary target conditions were the detection of grade 1 and grade 3 or higher-grade prostate cancer, and a potential change in the number of biopsy procedures.

SEARCH METHODS

We performed a comprehensive systematic literature search up to 31 July 2018. We searched CENTRAL, MEDLINE, Embase, eight other databases and one trials register.

SELECTION CRITERIA

We considered for inclusion any cross-sectional study if it investigated one or more index tests verified by the reference standard, or if it investigated the agreement between the MRI pathway and systematic biopsy, both performed in the same men. We included only studies on men who were biopsy naïve or who previously had a negative biopsy (or a mix of both). Studies involving MRI had to report on both MRI-positive and MRI-negative men. All studies had to report on the primary target condition.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed the risk of bias using the QUADAS-2 tool. To estimate test accuracy, we calculated sensitivity and specificity using the bivariate model. To estimate agreement between the MRI pathway and systematic biopsy, we synthesised detection ratios by performing random-effects meta-analyses. To estimate the proportions of participants with prostate cancer detected by only one of the index tests, we used random-effects multinomial or binary logistic regression models. For the main comparisions, we assessed the certainty of evidence using GRADE.

MAIN RESULTS

The test accuracy analyses included 18 studies overall.MRI compared to template-guided biopsy: Based on a pooled sensitivity of 0.91 (95% confidence interval (CI): 0.83 to 0.95; 12 studies; low certainty of evidence) and a pooled specificity of 0.37 (95% CI: 0.29 to 0.46; 12 studies; low certainty of evidence) using a baseline prevalence of 30%, MRI may result in 273 (95% CI: 249 to 285) true positives, 441 false positives (95% CI: 378 to 497), 259 true negatives (95% CI: 203 to 322) and 27 (95% CI: 15 to 51) false negatives per 1000 men. We downgraded the certainty of evidence for study limitations and inconsistency.MRI-targeted biopsy compared to template-guided biopsy: Based on a pooled sensitivity of 0.80 (95% CI: 0.69 to 0.87; 8 studies; low certainty of evidence) and a pooled specificity of 0.94 (95% CI: 0.90 to 0.97; 8 studies; low certainty of evidence) using a baseline prevalence of 30%, MRI-targeted biopsy may result in 240 (95% CI: 207 to 261) true positives, 42 (95% CI: 21 to 70) false positives, 658 (95% CI: 630 to 679) true negatives and 60 (95% CI: 39 to 93) false negatives per 1000 men. We downgraded the certainty of evidence for study limitations and inconsistency.The MRI pathway compared to template-guided biopsy: Based on a pooled sensitivity of 0.72 (95% CI: 0.60 to 0.82; 8 studies; low certainty of evidence) and a pooled specificity of 0.96 (95% CI: 0.94 to 0.98; 8 studies; low certainty of evidence) using a baseline prevalence of 30%, the MRI pathway may result in 216 (95% CI: 180 to 246) true positives, 28 (95% CI: 14 to 42) false positives, 672 (95% CI: 658 to 686) true negatives and 84 (95% CI: 54 to 120) false negatives per 1000 men. We downgraded the certainty of evidence for study limitations, inconsistency and imprecision.Systemic biopsy compared to template-guided biopsy: Based on a pooled sensitivity of 0.63 (95% CI: 0.19 to 0.93; 4 studies; low certainty of evidence) and a pooled specificity of 1.00 (95% CI: 0.91 to 1.00; 4 studies; low certainty of evidence) using a baseline prevalence of 30%, systematic biopsy may result in 189 (95% CI: 57 to 279) true positives, 0 (95% CI: 0 to 63) false positives, 700 (95% CI: 637 to 700) true negatives and 111 (95% CI: 21 to 243) false negatives per 1000 men. We downgraded the certainty of evidence for study limitations and inconsistency.Agreement analyses: In a mixed population of both biopsy-naïve and prior-negative biopsy men comparing the MRI pathway to systematic biopsy, we found a pooled detection ratio of 1.12 (95% CI: 1.02 to 1.23; 25 studies). We found pooled detection ratios of 1.44 (95% CI 1.19 to 1.75; 10 studies) in prior-negative biopsy men and 1.05 (95% CI: 0.95 to 1.16; 20 studies) in biopsy-naïve men.

AUTHORS' CONCLUSIONS

Among the diagnostic strategies considered, the MRI pathway has the most favourable diagnostic accuracy in clinically significant prostate cancer detection. Compared to systematic biopsy, it increases the number of significant cancer detected while reducing the number of insignificant cancer diagnosed. The certainty in our findings was reduced by study limitations, specifically issues surrounding selection bias, as well as inconsistency. Based on these findings, further improvement of prostate cancer diagnostic pathways should be pursued.

Magnetic resonance imaging-transrectal ultrasound image fusion guidance of prostate biopsies: current status, challenges and future perspectives

The use of multiparametric magnetic resonance imaging (mpMRI) in prostate cancer (PCa) diagnosis is rapidly evolving to try to overcome the limitations of the current diagnostic pathway using systematic transrectal ultrasound-guided biopsies (TRUS_bx) for all men with clinical suspicion of PCa. Prostate mpMRI allows for high quality lesion detection and characterization and has been shown to improve detection of significant PCa with a more accurate Gleason score grading. Suspicious lesions can be stratified by suspicion and sampled by selective MRI-guided targeted biopsies (TBx) for improved diagnostic accuracy. Several TBx methods have been established and include MRI/TRUS image fusion biopsies (cognitive or software-assisted) and in-bore biopsies, but none have yet proven superior in clinical practice. However, while MRI in-bore biopsy is not routinely used due to its costs and limited availability, MRI/TRUS image fusion is rapidly embraced as it allows skilled urologists to perform TBx in an outpatient clinic. Furthermore, it gives the operator the advantage of adding TBx to the systematic standard biopsy scheme, which is the currently recommended approach. With the anticipated increased future use of prebiopsy mpMRI, a more widespread implementation of MRI/TRUS image fusion platforms is concurrently expected in clinical practice. Therefore, the objective of this review is to assess the current status, challenges and future perspectives of prostate MRI/TRUS image fusion biopsies.