Magnetic resonance imaging for predicting prostate biopsy findings in patients considered for active surveillance of clinically low risk prostate cancer

Lower urinary tract symptoms in elderly men: Considerations for prostate cancer testing

PURPOSE

Both lower urinary tract symptoms (LUTS) and prostate cancer (PCa) are common in elderly men. While LUTS are generally due to a benign etiology, they may provoke an evaluation with prostate-specific antigen (PSA), which can lead to a cascade of further testing and possible overdiagnosis in patients with competing risks. There is limited patient and provider understanding of the relationship between LUTS and PCa risk, and a lack of clarity in how to evaluate these men to balance appropriate diagnosis of aggressive PCa with avoidance of overdiagnosis.

METHODS

A literature review was performed using keywords to query the electronic database PubMed. All articles published before November 2023 were screened by title and abstract for articles relevant to our subject.

RESULTS

Epidemiological studies suggest that LUTS and PCa are largely independent in elderly men. The best available tools to assess PCa risk include PSA permutations, novel biomarkers, and imaging, but there are limitations in older men based on lack of validation in the elderly and unclear applicability of traditional definitions of "clinically significant" disease. We present a three-tiered approach to evaluating these patients.

CONCLUSION

Elderly men commonly have LUTS as well as a high likelihood of indolent PCa. A systematic and shared decision-making-based approach can help to balance objectives of appropriate detection of phenotypically dangerous disease and avoidance of over-testing and overdiagnosis.

A prospective cohort of men with localized prostate cancer on active surveillance protocol in Hong Kong, China: what did we learn?

This study aimed to report the outcomes of active surveillance (AS) in the management of low-risk prostate cancer (PCa). It recruited 87 men who were prospectively followed up according to the Prostate Cancer Research International Active Surveillance (PRIAS) protocol with local adaptation at SH Ho Urology Centre, Prince of Wales Hospital, Hong Kong, China. We investigated the predictors of disease progression and found that baseline prostate-specific antigen density (PSAD) and the presence of the highest Prostate Imaging-Reporting and Data System (PI-RADS) score 5 lesion on magnetic resonance imaging (MRI) are significantly correlated with disease progression. Moreover, men with PSAD >0.2 ng ml -2 or PI-RADS 4 or 5 lesions had significantly worse upgrading-free survival compared to those with PSAD ≤0.2 ng ml -2 and PI-RADS 2 or 3 lesions. The study concludes that AS is a safe and effective management strategy for selected patients to defer radical treatment and that most disease progression can be detected after the first repeated biopsy. The combination of PSAD >0.2 ng ml -2 and PI-RADS 4 or 5 lesions may serve as a useful predictor of early disease progression and provide a guide to optimize follow-up protocols for men in different risk groups.

Advanced strain elastography is a reliable approach for prostate cancer detection in patients with elevated PSA levels

This study aimed to examine the validity and reproducibility of strain elastography (SE) for detecting prostate cancer (PCa) in patients with elevated prostate-specific antigen (PSA) levels. The study included 107 patients with elevated PSA levels. All eligible patients underwent transrectal ultrasound (TRUS) with real-time elastography (RTE) to detect suspicious lesions. Two readers independently evaluated the lesions and assigned a strain ratio and elastography score to each lesion. Histopathology was used as a reference standard to estimate the validity of RTE in predicting malignant lesions. An intraclass correlation (ICC) was performed to detect reliability of the strain ratios and elastography scores. TRUS-guided biopsy detected malignancies in 64 (59.8%) patients. TRUS with RTE revealed 122 lesions. The strain ratio index (SRI) cut-off values to diagnose malignancy were 4.05 and 4.35, with sensitivity, specificity, and accuracy of 94.7%, 91.3%, and 93.4%, respectively. An elastography score > 3 was the best cut-off value for detecting malignancy. According to readers, the sensitivity, specificity, and accuracy were 91.3-94.7%, 89.5-93.4%, and 91.3-90.9%, respectively. Excellent inter-reader agreement was recorded for SRI and elastography scores, with ICC of 0.937 and 0.800, respectively. SE proves to be an efficient tool for detecting PCa with high accuracy in patients with elevated PSA levels.

Diagnostic Accuracy of Contemporary Selection Criteria in Prostate Cancer Patients Eligible for Active Surveillance: A Bayesian Network Meta-Analysis

Background

Several active surveillance (AS) criteria have been established to screen insignificant prostate cancer (insigPCa, defined as organ confined, low grade and small volume tumors confirmed by postoperative pathology). However, their comparative diagnostic performance varies. The aim of this study was to compare the diagnostic accuracy of contemporary AS criteria and validate the absolute diagnostic odds ratio (DOR) of optimal AS criteria.

Methods

First, we searched Pubmed and performed a Bayesian network meta-analysis (NMA) to compare the diagnostic accuracy of contemporary AS criteria and obtained a relative ranking. Then, we searched Pubmed again to perform another meta-analysis to validate the absolute DOR of the top-ranked AS criteria derived from the NMA with two endpoints: insigPCa and favorable disease (defined as organ confined, low grade tumors). Subgroup and meta-regression analyses were conducted to identify any potential heterogeneity in the results. Publication bias was evaluated.

Results

Seven eligible retrospective studies with 3,336 participants were identified for the NMA. The diagnostic accuracy of AS criteria ranked from best to worst, was as follows: Epstein Criteria (EC), Yonsei criteria, Prostate Cancer Research International: Active Surveillance (PRIAS), University of Miami (UM), University of California-San Francisco (UCSF), Memorial Sloan-Kettering Cancer Center (MSKCC), and University of Toronto (UT). I² = 50.5%, and sensitivity analysis with different insigPCa definitions supported the robustness of the results. In the subsequent meta-analysis of DOR of EC, insigPCa and favorable disease were identified as endpoints in ten and twenty-two studies, respectively. The pooled DOR for insigPCa and favorable disease were 0.44 (95%CI, 0.31–0.58) and 0.66 (95%CI, 0.61–0.71), respectively. According to a subgroup analysis, the DOR for favorable disease was significantly higher in US institutions than that in other regions. No significant heterogeneity or evidence of publication bias was identified.

Conclusions

Among the seven AS criteria evaluated in this study, EC was optimal for positively identifying insigPCa patients. The pooled diagnostic accuracy of EC was 0.44 for insigPCa and 0.66 when a more liberal endpoint, favorable disease, was used.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], PROSPERO [CRD42020157048].

Active Surveillance Strategies for Low-Grade Prostate Cancer: Comparative Benefits and Cost-effectiveness

Background Active surveillance (AS) is the recommended treatment option for low-risk prostate cancer (PC). Surveillance varies in MRI, frequency of follow-up, and the Prostate Imaging Reporting and Data System (PI-RADS) score that would repeat biopsy. Purpose To compare the effectiveness and cost-effectiveness of AS strategies for low-risk PC with versus without MRI. Materials and Methods This study developed a mathematical model to evaluate the cost-effectiveness of surveillance strategies in a simulation of men with a diagnosis of low-risk PC. The following strategies were compared: watchful waiting, prostate-specific antigen (PSA) and annual biopsy without MRI, and PSA testing and MRI with varied PI-RADS thresholds for biopsy. MRI strategies differed regarding scheduling and use of PI-RADS score of at least 3, or a PI-RADS score of at least 4 to indicate the need for biopsy. Life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated by using microsimulation. Sensitivity analysis was used to assess the impact of varying parameter values on results. Results For the base case of 60-year-old men, all strategies incorporating prostate MRI extended QALYs and life-years compared with watchful waiting and non-MRI strategies. Annual MRI strategies yielded 16.19 QALYs, annual biopsy with no MRI yielded 16.14 QALYs, and watchful waiting yielded 15.94 QALYs. Annual MRI with PI-RADS score of at least 3 or of at least 4 as the biopsy threshold and annual MRI with biopsy even after MRI with negative findings offered similar QALYs and the same unadjusted life expectancy: 23.05 life-years. However, a PI-RADS score of at least 4 yielded 42% fewer lifetime biopsies. With a cost-effectiveness threshold of $100 000 per QALY, annual MRI with biopsy for lesions with PI-RADS scores of 4 or greater was most cost-effective (incremental cost-effectiveness ratio, $67 221 per QALY). Age, treatment type, risk of initial grade misclassification, and quality-of-life impact of procedural complications affected results. Conclusion The use of active surveillance (AS) with biopsy decisions guided by findings from annual MRI reduces the number of biopsies while preserving life expectancy and quality of life. Biopsy in lesions with PI-RADS scores of 4 or greater is likely the most cost-effective AS strategy for men with low-risk prostate cancer who are younger than 70 years. © RSNA, 2021 Online supplemental material is available for this article. An earlier incorrect version appeared online. This article was corrected on July 13, 2021.

Defining the index lesion for potential salvage partial or hemi-gland ablation after radiation therapy for localized prostate cancer

BACKGROUND

Salvage partial gland ablation (sPGA) has been proposed to treat some localized radiorecurrent prostate cancer. The role of prostate biopsy and magnetic resonance imaging (MRI) characteristics to identify patients eligible for sPGA is unknown.

OBJECTIVE

To evaluate the ability of MRI and prostate biopsy characteristics to identify an index lesion suitable for sPGA and validate this selection using detailed tumor maps created from whole-mount slides from salvage radical prostatectomy (sRP) specimens.

DESIGN, SETTING, AND PARTICIPANTS

Men who underwent sRP for recurrent prostate cancer following primary radiotherapy with external beam radiotherapy (EBRT) and/or brachytherapy between 2000 and 2014 at a single high-volume cancer center were eligible. Those with tumor maps, MRI and biopsy data were included in analysis.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Primary outcome was the ability of clinicopathologic and imaging criteria to identify patients who may be eligible for sPGA based on detailed tumor map from whole-mount sRP slides.

RESULTS AND LIMITATIONS

Of 216 men who underwent sRP following whole gland radiotherapy, tumor maps, MRI, and biopsy data were available for 77. Of these, 15 (19%) were determined to be eligible for sPGA based on biopsy-proven unilateral disease in contiguous sextant segments, a dominant lesion on MRI concordant with biopsy location or no focal region of interest, and no imaging evidence of extraprostatic disease. Review of tumor maps identified 6 additional men who would have met criteria for sPGA, resulting in sensitivity of 71% (95% C.I. 48%-89%) and specificity of 100% (lower bound of 95% C.I. 94%). None of the 15 men who met the criteria for sPGA on clinical data were identified incorrectly on tumor maps to require full gland surgery (upper bound of 95% C.I. 22%). Median tumor volume of the index lesion was 0.4 cc and recurrent cancer was noted in the apex, mid-gland, and base in 81%, 100%, and 29% of men.

CONCLUSIONS

In men with recurrent prostate cancer after radiotherapy, biopsy findings and MRI can be used to select index lesions potentially amenable for sPGA and can guide patient evaluation for inclusion in clinical trials of sPGA following radiation failure. Larger, prospective studies are required to evaluate both the role of MRI and clinical criteria in guiding focal salvage therapy and the effectiveness of this modality for radiorecurrent prostate cancer.

[Active surveillance of prostate cancer: treatement-free survival according to restricted or expanded eligibility criteria]

AIM

Overtreatment is an actual problem in low risk localized prostate cancer (PC) management. Active surveillance (AS) is a solution to limit this problem, but eligibility criteria remained discussed. The aim was to assess possibilities of widening selection criteria for patient in AS, studying curative treatment free survival (CTFS) according to restricted or expanded eligibility criteria.

METHODS

We retrospectively studied patients beginning AS between 2008 and 2014, for Gleason 6 localized PC, PSA<15ng/ml,<cT3. The group "strict criteria" was defined:≤cT2a, PSA<10ng/ml, 2≤positive biopsies (PB+), total tumoral length≤3mm, tumoral invading≤50%, PSA density≤0,15ng/ml/cm³. MRI was performed at baseline and during follow-up. Radical treatment was proposed in case of biological, histological or clinical progression. Criteria associated with AS survival were analyzed by Cox regression.

RESULTS

One hundred eighty patients were included (follow-up 46 months). One hundred and eleven patients had "strict" criteria vs. 69 "expanded" criteria. Eighty-two patients (45%) were treated with median time of 18.2 months (CTFS was 71% at 2 years, 52% at 5 years.). The widening of the inclusion criteria was not associated with CTFS (65 vs 54% at 5 years, P=0.13). Factors significatively associated with discontinuation of AS were bilaterality (HR=2.12) and abnormal rectal digital examination cT2 (HR=2,07); MRI target (HR=2,48)) tended towards significance.

CONCLUSION

Our study concludes that curative treatment free survival is similar for patients included with expanded criteria compared with those included with strict criteria. However, high initial cancer volume) is associated with AS discontinuation.

LEVEL OF EVIDENCE

3.

Utilization of Multiparametric MRI of Prostate in Patients under Consideration for or Already in Active Surveillance: Correlation with Imaging Guided Target Biopsy

This study sought to assess the value of multiparametric magnetic resonance image (mp-MRI) in patients with a prostate cancer (PCa) Gleason score of 6 or less under consideration for or already in active surveillance and to determine the rate of upgrading by target biopsy. Three hundred and fifty-four consecutive men with an initial transrectal ultrasound-guided (TRUS) biopsy-confirmed PCa Gleason score of 6 or less under clinical consideration for or already in active surveillance underwent mp-MRI and were retrospectively reviewed. One hundred and nineteen of 354 patients had cancer-suspicious regions (CSRs) at mp-MRI. Each CSR was assigned a Prostate Imaging Reporting and Data System (PI-RADS) score based on PI-RADS v2. One hundred and eight of 119 patients underwent confirmatory imaging-guided biopsy for CSRs. Pathology results including Gleason score (GS) and percentage of specimens positive for PCa were recorded. Associations between PI-RADS scores and findings at target biopsy were evaluated using logistic regression. At target biopsy, 81 of 108 patients had PCa (75%). Among them, 77 patients had upgrading (22%, 77 of 354 patients). One hundred and forty-six CSRs in 108 patients had PI-RADS 3 n = 28, 4 n = 66, and 5 n = 52. The upgraded rate for each category of CSR was for PI-RADS 3 (5 of 28, 18%), 4 (47 of 66, 71%) and 5 (49 of 52, 94%). Using logistic regression analysis, differences in PI-RADS scores from 3 to 5 are significantly associated with the probability of disease upgrade (20%, 73%, and 96% for PI-RADS score of 3, 4, and 5, respectively). Adding mp-MRI to patients under consideration for or already in active surveillance helps to identify undiagnosed PCa of a higher GS or higher volume resulting in upgrading in 22%.

Prostate Health Index and multiparametric magnetic resonance imaging to predict prostate cancer grade reclassification in active surveillance

OBJECTIVE

To identify the value of combining the Prostate Health Index (PHI) and multiparametric magnetic resonance imaging (mpMRI), tools which have previously been shown to be independently predictive of prostate cancer (PCa) grade reclassification (GR; Gleason score >6), for the purpose of predicting GR at the next surveillance biopsy to reduce unnecessary prostate biopsies for men in PCa active surveillance (AS).

PATIENTS AND METHODS

Between 2014 and 2019, we retrospectively identified 253 consecutive men in the Johns Hopkins AS programme who had mpMRI and PHI followed by a systematic ± targeted biopsy. PHI and PHI density (PHID) were evaluated across Prostate Imaging-Reporting and Data System version 2.0 (PI-RADSv2) scores and compared to those with and without GR. Next, the negative predictive value (NPV) and area under the receiver operating curve (AUC) were calculated to compare the diagnostic value of PI-RADSv2 score combined with PHI, PHID, or prostate-specific antigen density (PSAD) for GR using their respective first quartile as a cut-off.

RESULTS

Of the 253 men, 38 men (15%) had GR. Men with GR had higher PHI values (40.7 vs 32.0, P = 0.001), PHID (0.83 vs 0.57, P = 0.007), and PSAD (0.12 vs 0.10, P = 0.037). A PI-RADSv2 ≤3 alone had a NPV of 91.6% for GR (AUC 0.67). Using a PHI cut-off of 25.6 in addition to PI-RADSv2 ≤3, the NPV and AUC were both increased to 98% and 0.70, respectively. Using a PSAD cut-off of 0.07 ng/mL/mL with PI-RADSv2 had an AUC of 0.69 and NPV of 95.4%. PHI and PI-RADSv2 together could have avoided 20% of biopsies at the cost of missing 2.6% of GRs.

CONCLUSIONS

The combination of PHI and mpMRI can aid in the prediction of GR in men on AS and may be useful for decreasing the burden of surveillance prostate biopsies.

Magnetic Resonance Imaging for the Detection of High Grade Cancer in the Canary Prostate Active Surveillance Study

PURPOSE

We investigated the ability of prostate magnetic resonance imaging to detect Gleason Grade Group 2 or greater cancer in a standardized, multi-institutional active surveillance cohort.

MATERIALS AND METHODS

We evaluated men enrolled in Canary Prostate Active Surveillance Study with Gleason Grade Group less than 2 and who underwent biopsy within 12 months of multiparametric magnetic resonance imaging. Our primary outcome was biopsy reclassification to Gleason Grade Group 2 or greater. We evaluated the performance of magnetic resonance imaging PI-RADS® score and clinical factors. Multivariable logistic regression models were fit with magnetic resonance imaging and clinical factors and used to perform receiver operating curve analyses.

RESULTS

There were 361 participants with 395 prostate magnetic resonance imaging studies with a median followup of 4.1 (IQR 2.0-7.6) years. Overall 108 (27%) biopsies showed reclassification. Defining positive magnetic resonance imaging as PI-RADS 3-5, the negative predictive value and positive predictive value for detecting Gleason Grade Group 2 or greater cancer was 83% (95% CI 76-90) and 31% (95% CI 26-37), respectively. PI-RADS was significantly associated with reclassification (PI-RADS 5 vs 1 and 2 OR 2.71, 95% CI 1.21-6.17, p=0.016) in a multivariable model but did not improve upon a model with only clinical factors (AUC 0.768 vs 0.762). In 194 fusion biopsies higher grade cancer was found in targeted cores in 21 (11%) instances, while 25 (13%) had higher grade cancer in the systematic cores.

CONCLUSIONS

This study adds the largest cohort data to the body of literature for magnetic resonance imaging in active surveillance, recommending systematic biopsy in patients with negative magnetic resonance imaging and the inclusion of systematic biopsy in patients with positive magnetic resonance imaging.

Active Surveillance of Prostate Cancer Using Multiparametric Magnetic Resonance Imaging: A Review of the Current Role and Future Perspectives

Clinically, active surveillance involves continuous monitoring of patients who may be at risk for disease. Patients with low-grade and early-stage prostate cancer may benefit from active surveillance, rather than undergoing surgical and medical treatments that are associated with side effects. In these cases, the role of active surveillance is to ensure that there is no progression of the disease. However, active surveillance may be associated with a risk of under-diagnosis. Previously, the assignment of risk categories and patient monitoring were based on digital rectal examination, transrectal prostate biopsy, and monitoring of serum levels of prostate-specific antigen (PSA). Multiparametric magnetic resonance imaging (MRI) of the prostate gland has an estimated negative predictive value of 95% for the detection of prostate cancer, which makes this an effective imaging method for targeting biopsies and for monitoring patients over time. Also, multiparametric MRI-guided biopsy at the initial stage of the risk stratification for patients who are newly diagnosed with prostate cancer may reduce the number of underdiagnosed patients, improve long-term patient prognosis, and reduce the number of patients who are overtreated, which may reduce healthcare costs and reduce treatment morbidity. For these reasons, multiparametric MRI has become an accepted monitoring tool in patients who are enrolled in active surveillance programs. This review aims to present the current status of the use of multiparametric MRI in active surveillance of prostate cancer and to discuss future perspectives, supported by recent literature.

MRI to guide biopsies or avoid biopsies?

PURPOSE OF REVIEW

To discuss contemporary data on the value of multiparametric MRI (mpMRI) for guiding the decision to biopsy men at risk for prostate cancer, as well as its utility in active surveillance programs.

RECENT FINDINGS

Although a systematic 12-core biopsy is the current standard of care for men with increased suspicion for prostate cancer, MRI with or without targeted biopsy has been shown to reliably improve the detection of clinically significant disease following a prior negative biopsy. At the same time, there is a growing body of evidence to support the use of MRI for diagnostic purposes in biopsy-naive patients, as well for enrolling and monitoring men on active surveillance programs.

SUMMARY

mpMRI is an evolving technology with great promise for altering our approach to prostate cancer diagnosis and surveillance. In conjunction with targeted biopsies, MRI offers greater specificity for the detection of clinically significant cancer and therefore may help to reduce overdetection of indolent disease while minimizing the risks and limitations of systematic biopsies.

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.

Standardized Magnetic Resonance Imaging Reporting Using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation Criteria and Magnetic Resonance Imaging/Transrectal Ultrasound Fusion with Transperineal Saturation Biopsy to Select Men on Active Surveillance

BACKGROUND

Contemporary selection criteria for men with prostate cancer (PC) suitable for active surveillance (AS) are unsatisfactory, leading to high disqualification rates based on tumor misclassification. Conventional biopsy protocols are based on standard 12-core transrectal ultrasound (TRUS) biopsy.

OBJECTIVE

To assess the value of magnetic resonance imaging (MRI)/TRUS fusion biopsy over 4-yr follow-up in men on AS for low-risk PC.

DESIGN, SETTING, AND PARTICIPANTS

Between 2010 and 2018, a total of 273 men were included. Of them, 157 men with initial 12-core TRUS biopsy and 116 with initial MRI/TRUS fusion biopsy were followed by systematic and targeted transperineal MRI/TRUS fusion biopsies based on Prostate Cancer Research International Active Surveillance criteria. MRI from follow-up MRI/TRUS fusion biopsy was assessed using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) scoring system.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

AS-disqualification rates for patients on AS initially diagnosed by either 12-core TRUS biopsy or by MRI/TRUS fusion biopsy were compared using Kaplan-Meier estimates, log-rank tests, and regression analyses. We also analyzed the influence of negative primary MRI and PRECISE scoring to predict AS disqualification using Kaplan-Meier estimates, log-rank tests, and receiver operating characteristic (ROC) curve analysis.

RESULTS AND LIMITATIONS

Of men diagnosed by 12-core TRUS biopsy, 59% were disqualified from AS based on the results of subsequent MRI/TRUS fusion biopsy. In the initial MRI fusion biopsy cohort, upgrading occurred significantly less frequently (19%, p<0.001). ROC curve analyses demonstrated good discrimination for the PRECISE score with an area under the curve of 0.83. No men with a PRECISE score of 1 or 2 (demonstrating absence or downgrading of lesions in follow-up MRI) were disqualified from AS. In our cohort, a negative baseline MRI scan was not a predictor of nondisqualification from AS. Limitations include transperineal approach and extended systematic biopsies used with MRI/TRUS fusion biopsy, which may not be representative of other centers.

CONCLUSIONS

MRI/TRUS fusion biopsies allow a reliable risk classification for patients who are candidates for AS. The application of the PRECISE scoring system demonstrated good discrimination.

PATIENT SUMMARY

In this study, we investigated the value of multiparametric magnetic resonance imaging (MRI) and MRI/transrectal ultrasound (TRUS) fusion biopsies for the assessment of active surveillance (AS) reliability using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation criteria. Standard TRUS biopsies lead to significant underestimation of prostate cancer. In contrast, MRI/TRUS fusion biopsies allowed for a more reliable risk classification. For appropriate inclusion into AS, men should receive either an initial or a confirmatory MRI/TRUS fusion biopsy.

Contemporary approach to active surveillance for favorable risk prostate cancer

The approach to favorable risk prostate cancer known as “active surveillance” was first described explicitly in 2002. This was a report of 250 patients managed with a strategy of expectant management, with serial prostate-specific antigen and periodic biopsy, and radical intervention advised for patients who were re-classified as higher risk. This was initiated as a prospective clinical trial, complete with informed consent, beginning in 2007. Thus, there are now 20 years of experience with this approach, which has become widely adopted around the world. In this chapter, we will summarize the biological basis for active surveillance, review the experience to date of the Toronto and Hopkins groups which have reported 15-year outcomes, describe the current approach to active surveillance in patients with Gleason score 3 + 3 or selected patients with Gleason score 3 + 4 with a low percentage of Gleason pattern 4 who may also be candidates, enhanced by the use of magnetic resonance imaging, and forecast future directions.

Role of multiparametric magnetic resonance imaging for patients under active surveillance for prostate cancer: a systematic review with diagnostic meta-analysis

BACKGROUND

The use of multiparametric magnetic resonance imaging (mpMRI) in the setting of patients under active surveillance (AS) is promising. In this systematic-review we aimed to analyse the role of mpMRI in patients under AS.

METHODS

A comprehensive literature research for English-language original and review articles, recently published, was carried out using Medline, Scopus and Web of sciences databases until 30 October 2017. The following MeSH terms were used: 'active surveillance', 'prostate cancer', 'multiparametric magnetic resonance imaging'. A diagnostic meta-analysis was performed for 3.0 T mpMRI in predicting disease re-classification.

RESULTS

In total, 226 studies were selected after research and after removal of duplicates. After analysis on inclusion criteria, 43 studies were identified as eligible for this systematic review with a total of 6,605 patients. The timing of MRI during follow-up of AS differed from all studies like criteria for inclusion in the AS protocol. Overall, there was a low risk of bias across all studies. The diagnostic meta-analysis for 1.5 tesla showed a sensitivity of 0.60, negative predictive value (NPV) of 0.75 and a hierarchical summary receiving operating curve (HSROC) of 0.74 while for 3.0 tesla mpMRI a sensitivity of 0.81, a NPV of 0.78 and a HSROC of 0.83.

CONCLUSIONS

Overall, the available evidence suggests that both 1.5 or 3.0 Tesla mpMRI are a valid tool to monitor progression during AS follow-up, showing good accuracy capabilities in detecting PCa re-classification. However, the modality to better define what means 'disease progression' on mpMRI must be further evaluated.

Does the introduction of prostate multiparametric magnetic resonance imaging into the active surveillance protocol for localized prostate cancer improve patient re-classification?

OBJECTIVES

To determine whether replacement of protocol-driven repeat prostate biopsy (PB) with multiparametric magnetic resonance imaging (mpMRI) ± repeat targeted prostate biopsy (TB) when evaluating men on active surveillance (AS) for low-volume, low- to intermediate-risk prostate cancer (PCa) altered the likelihood of or time to treatment, or reduced the number of repeat biopsies required to trigger treatment.

PATIENTS AND METHODS

A total of 445 patients underwent AS in the period 2010-2016 at our institution, with a median (interquartile range [IQR]) follow-up of 2.4 (1.2-3.7) years. Up to 2014, patients followed a 'pre-2014' AS protocol, which incorporated PB, and subsequently, according to the 2014 National Institute for Health and Care Excellence (NICE) guidelines, patients followed a '2014-present' AS protocol that included mpMRI. We identified four groups of patients within the cohort: 'no mpMRI and no PB'; 'PB alone'; 'mpMRI ± TB'; and 'PB and mpMRI ± TB'. Kaplan-Meier plots and log-rank tests were used to compare groups.

RESULTS

Of 445 patients, 132 (30%) discontinued AS and underwent treatment intervention, with a median (IQR) time to treatment of 1.55 (0.71-2.4) years. The commonest trigger for treatment was PCa upgrading after mpMRI and TB (43/132 patients, 29%). No significant difference was observed in the time at which patients receiving a PB alone or receiving mpMRI ± TB discontinued AS to undergo treatment (median 1.9 vs 1.33 years; P = 0.747). Considering only those patients who underwent repeat biopsy, a greater proportion of patients receiving TB after mpMRI discontinued AS compared with those receiving PB alone (29/66 [44%] vs 32/87 [37%]; P = 0.003). On average, a single set of repeat biopsies was needed to trigger treatment regardless of whether this was a PB or TB.

CONCLUSIONS

Replacing a systematic PB with mpMRI ±TB as part of an AS protocol increased the likelihood of re-classifying patients on AS and identifying men with clinically significant disease requiring treatment. mpMRI ±TB as part of AS thereby represents a significant advance in the oncological safety of the AS protocol.

Comparisons between magnetic resonance/ultrasound fusion-guided biopsy and standard biopsy in the diagnosis of prostate cancer: A prospective cohort study

Prostate-specific antigen is not useful for detection of prostate cancer in Chinese men. The major problems in prostate cancer patients are overdiagnosis and overtreatment. The objective of the study was to test the hypothesis that targeted biopsy is an accurate diagnostic tool for prostate cancer detection than standard biopsy in Chinese men.Total, 998 patients whom multiparticulate multiparametric magnetic resonance imaging had revealed at least 1 lesion in the prostate were included in a cohort. Patients were subjected to magnetic resonance imaging (MRI)/ultrasound (US) fusion-guided biopsy followed US-guided biopsy. Benefits of a diagnostic test were evaluated by decision curve analysis. Patients who were diagnosed as having prostate cancer by either of biopsies were subjected to radical prostatectomies followed by whole-mounted pathology (n = 578). Spearman rank correlation was performed between the biopsy results and the subtype of prostate cancer at 99% of confidence level.With respect to whole-mounted pathology, for US-guided biopsy, MRI/US fusion-guided biopsy, and combined data of both biopsies, sensitivities were 0.973, 0.983, and 0.973 and accuracies were 0.837, 0.91, and 0.917, respectively. MRI/US fusion-guided biopsy (P = .165) and combined data of both biopsies (P = .182) had the same specificity to whole-mount pathology. However, a US-guided biopsy had not the same specificity to whole-mount pathology (P = .0003). Decision-making zones for radical prostatectomy of different biopsies were in the order of combined data of both biopsies >MRI/US fusion-guided biopsy >US-guided biopsy.Only the targeted biopsy is recommended for the diagnosis of prostate cancer.

Comparison of conventional transrectal ultrasound, magnetic resonance imaging, and micro-ultrasound for visualizing prostate cancer in an active surveillance population: A feasibility study

INTRODUCTION

Active surveillance monitoring of prostate cancer is unique in that most patients have low-grade disease that is not well-visualized by any common imaging technique. High-resolution (29 MHz) micro-ultrasound is a new, real-time modality that has been demonstrated to be sensitive to significant prostate cancer and effective for biopsy targeting. This study compares micro-ultrasound imaging with magnetic resonance imaging (MRI) and conventional ultrasound for visualizing prostate cancer in active surveillance.

METHODS

Nine patients on active surveillance were imaged with multiparametric (mp) MRI prior to biopsy. During the biopsy procedure, imaging and target identification was first performed using conventional ultrasound, then using micro-ultrasound. The mpMRI report was then unblinded and used to determine cognitive fusion targets. Using micro-ultrasound, biopsy samples were taken from targets in each modality, plus 12 systematic samples.

RESULTS

mpMRI and micro-ultrasound both demonstrated superior sensitivity to Gleason sum 7 or higher cancer compared to conventional ultrasound (p=0.02 McNemar's test). Micro-ultrasound detected 89% of clinically significant cancer, compared to 56% for mpMRI.

CONCLUSIONS

Micro-ultrasound may provide similar sensitivity to clinically significant prostate cancer as mpMRI and visualize all significant mpMRI targets. Unlike mpMRI, micro-ultrasound is performed in the office, in real-time during the biopsy procedure, and so is expected to maintain the cost-effectiveness of conventional ultrasound. Larger studies are needed before these results may be applied in a clinical setting.

Low-risk prostate cancer selected for active surveillance with negative MRI at entry: can repeat biopsies at 1 year be avoided? A pilot study

PURPOSE

In patients considered for active surveillance (AS), the use of MRI and targeted biopsies (TB) at entry challenges the approach of routine "per protocol" repeat systematic biopsies (SB) at 1 year. This pilot study aimed to assess whether an approach of performing repeat biopsies only if PSA kinetics are abnormal would be safe and sufficient to detect progression.

METHODS

Prospective single-centre study of 149 patients on AS with low-risk PCa, a negative MRI at entry, followed for a minimum of 12 months between 01/2007 and 12/2015. Group 1 (n = 78) patients had per-protocol 12-month repeat SB; group 2 (n = 71) patients did not. Surveillance tests for tumour progression were for both groups: for cause SB and MRI-TB biopsies if PSA velocity (PSA-V) > 0.75 ng/ml/year, or PSA doubling time (PSADT) < 3 years. The main objectives are to compare the 2-year rates of tumour progression and AS discontinuation between groups. The secondary objectives are to estimate the diagnostic power of PSA-V and PSA-DT, to predict the risk of tumour progression.

RESULTS

Overall, 21 out of 149 patients (14.1%) showed tumour progression, 17.1% for group 1 and 12.3% for group 2, and 31 (21.2%) discontinued AS at 2 years. There was no difference between the 2 groups (p = 0.56). The area under the PSA-V and PSADT curves to predict tumour progression was 0.92 and 0.83, respectively.

CONCLUSIONS

We did not find any significant difference for progression and AS discontinuation rate between the 2 groups. The PSA kinetic seems accurate as a marker of tumour progression. These results support the conduct of a multi-centre prospective trial to confirm these findings.

Multiparametric Magnetic Resonance Imaging for Active Surveillance of Prostate Cancer

Active surveillance has gained popularity as an acceptable management option for men with low-risk prostate cancer. Successful utilization of this strategy can delay or prevent unnecessary interventions - thereby reducing morbidity associated with overtreatment. The usefulness of active surveillance primarily depends on correct identification of patients with low-risk disease. However, current population-wide algorithms and tools do not adequately exclude high-risk disease, thereby limiting the confidence of clinicians and patients to go on active surveillance. Novel imaging tools such as mpMRI provide information about the size and location of potential cancers enabling more informed treatment decisions. The term “multiparametric” in prostate mpMRI refers to the summation of several MRI series into one examination whose initial goal is to identify potential clinically-significant lesions suitable for targeted biopsy. The main advantages of MRI are its superior anatomic resolution and the lack of ionizing radiation. Recently, the Prostate Imaging-Reporting and Data System has been instituted as an international standard for unifying mpMRI results. The imaging sequences in mpMRI defined by Prostate Imaging Reporting and Data System version 2 includes: T2-weighted MRI, diffusion-weighted MRI, derived apparent-diffusion coefficient from diffusion-weighted MRI, and dynamic contrast-enhanced MRI. The use of mpMRI prior to starting active surveillance could prevent those with missed, high-grade lesions from going on active surveillance, and reassure those with minimal disease who may be hesitant to take part in active surveillance. Although larger validation studies are still necessary, preliminary results suggest mpMRI has a role in selecting patients for active surveillance. Less certain is the role of mpMRI in monitoring patients on active surveillance, as data on this will take a long time to mature. The biggest obstacles to routine use of prostate MRI are quality control, cost, reproducibility, and access. Nevertheless, there is great a potential for mpMRI to improve outcomes and quality of treatment. The major roles of MRI will continue to expand and its emerging use in standard of care approaches becomes more clearly defined and supported by increasing levels of data.

Active surveillance for low-risk prostate cancer

PURPOSE OF REVIEW

The approach of active surveillance for low-risk prostate cancer has evolved in many ways since its introduction 20 years ago. There is a great deal of ongoing research addressing the molecular genetics and clinical outcome of low-risk disease, the use of MRI and biomarkers, and the role of lifestyle and dietary modifications. The major developments in the field are reviewed in this article.

RECENT FINDINGS

Low risk and many cases of low-intermediate risk prostate cancer are indolent, have little or no metastatic potential, and do not pose a threat to the patient in his lifetime. These are termed clinically insignificant. Studies over the last 20 years have advanced our understanding of who these patients are, and promoted the use of conservative management in such individuals. A key component of this approach is the early identification of those patients who have been misattributed as having low-risk disease, who in fact harbor higher risk disease and are likely to benefit from definitive therapy. This represents about 30% of newly diagnosed low-risk patients. A further small proportion of patients with low-risk disease demonstrate biological progression to higher grade disease. Extent of Gleason 6 on biopsy, Prostate Specific Antigen density, and race are predictors for the likelihood of coexistent higher grade cancer.

SUMMARY

The results of active surveillance, embodying conservative management with selective, delayed intervention for the subset who are reclassified as higher risk over time based on repeat biopsy, imaging, or biomarker results, have shown that this approach is safe in the intermediate to long term, with a 0.5-3% cancer-specific mortality at 10-15 years. Further refinement incorporating MRI and targeted biopsies is the subject of intensive research at the moment, and promises to improve the safety and precision of conservative management.

Active surveillance review: contemporary selection criteria, follow-up, compliance and outcomes

The primary goal of active surveillance (AS) is to prevent overtreatment by selecting patients with low-risk prostate cancer (PCa) and closely monitoring them so that definitive treatment can be offered when needed. With the increasing popularity of AS as a management strategy for men with localized PCa, it is important to understand all the contemporary guidelines and criteria that exist for AS and the differences among them. No single optimal management strategy for clinically localized, early-stage disease has been universally accepted. The implementation of AS varies widely between institutions, from inclusion criteria to follow-up protocols, with the most notable differences seen in maximum accepted Gleason score, T-stage and prostate-specific antigen (PSA) parameters. The objectives of this review were to systematically summarize the current literature on AS strategy, present an overview of the various published guidelines and criteria that are used for AS at several major institutions as well as discuss goals and trade-offs of the various criteria. A comprehensive search of the PubMed and Embase databases from 1990 to 2017 was performed to identify studies pertaining to AS criteria and trends. Trends in AS uptake and use in Canada, USA and Europe were reviewed to demonstrate the current trends and outcomes of AS to offer greater insight into the differences, nature and efficacy of various AS protocols. AS is a compelling antidote to the current PCa overtreatment phenomena; however, when considering patients for AS it is important to understand the differences between protocols, and review published results to appreciate the impact on follow-up.

Anatomic and Molecular Imaging in Prostate Cancer

Prostate cancer is characterized by a complex set of heterogeneous disease states. This review aims to describe how imaging has been studied within each specific state. As physicians transition into an era of precision medicine, multiparametric magnetic resonance imaging (mpMRI) is proving to be a powerful tool leading the way for a paradigm shift in the diagnosis and management of localized prostate cancer. With further research and development, molecular imaging modalities will likely change the way we approach recurrent and metastatic disease. Given the range of possible oncological progression patterns, a thorough understanding of the underlying carcinogenesis, as it relates to imaging, is a requisite if we are to appropriately manage prostate cancer in future decades.

Magnetic resonance imaging in active surveillance-a modern approach

In recent years, active surveillance has been increasingly adopted as a conservative management approach to low and sometimes intermediate risk prostate cancer, to avoid or delay treatment until there is evidence of higher risk disease. A number of studies have investigated the role of multiparametric magnetic resonance imaging (mpMRI) in this setting. MpMRI refers to the use of multiple MRI sequences (T2-weighted anatomical and functional imaging which can include diffusion-weighted imaging, dynamic contrast enhanced imaging, spectroscopy). Each of the parameters investigates different aspects of the prostate gland (anatomy, cellularity, vascularity, etc.). In addition to a qualitative assessment, the radiologist can also extrapolate quantitative imaging biomarkers from these sequences, for example the apparent diffusion coefficient from diffusion-weighted imaging. There are many different types of articles (e.g., reviews, commentaries, consensus meetings, etc.) that address the use of mpMRI in men on active surveillance for prostate cancer. In this paper, we compare original articles that investigate the role of the different mpMRI sequences in men on active surveillance for prostate cancer, in order to discuss the relative utility of the different sequences, and combinations of sequences. We searched MEDLINE/PubMed for manuscripts published from inception to 1^st December 2017. The search terms used were (prostate cancer or prostate adenocarcinoma or prostatic carcinoma or prostate carcinoma or prostatic adenocarcinoma) and (MRI or NMR or magnetic resonance imaging or mpMRI or multiparametric MRI) and active surveillance. Overall, 425 publications were found. All abstracts were reviewed to identify papers with original data. Twenty-five papers were analysed and summarised. Some papers based their analysis only on one mpMRI sequence, while others assessed two or more. The evidence from this review suggests that qualitative assessments and quantitative data from different mpMRI sequences hold promise in the management of men on active surveillance for prostate cancer. Both qualitative and quantitative approaches should be considered when assessing mpMRI of the prostate. There is a need for robust studies assessing the relative utility of different combinations of sequences in a systematic manner to determine the most efficient use of mpMRI in men on active surveillance.

PI-RADS v2 and periprostatic fat measured on multiparametric magnetic resonance imaging can predict upgrading in radical prostatectomy pathology amongst patients with biopsy Gleason score 3 + 3 prostate cancer

PURPOSE

An underestimated biopsy Gleason score 3 + 3 can result in unfounded optimism amongst patients and cause physicians to miss the window for prostate cancer (PCa) cure. This study aims to evaluate the effectiveness of Prostate Imaging Reporting and Data System (PI-RADS) version 2 as well as periprostatic fat (PPF) measured on multiparametric magnetic resonance imaging (mp-MRI) at predicting pathological upgrading amongst patients with biopsy Gleason score 3 + 3 disease.

PATIENTS AND METHODS

A retrospective analysis of 56 patients with biopsy Gleason score 6 PCa who underwent prebiopsy mp-MRI and radical prostatectomy (RP) between November 2013 and March 2018 was conducted. Two radiologists performed PI-RADS v2 score evaluation and different fat measurements on mp-MRI. The associations amongst clinical information, PI-RADS v2 score, different fat parameters and pathologic findings were analyzed. A nomogram predicting upgrading was established based on the results of logistic regression analysis.

RESULTS

A total of 38 (67.9%) patients were upgraded to Gleason ≥7 disease on RP specimens. Prostate-specific antigen density (PSAD) (p < .001), positive core (p < .001), single-core positivity (p = .039), PI-RADS score (p < .001), front PPF area (p = .007) and front-to-total ratio (the ratio of front PPF area to total contour area) (p < .001) were risk factors for upgrading. On multivariate analysis, Epstein criteria (p = .02), PI-RADS score >3 (p = .024), and front-to-total ratio (p = .006) were independent risk factors for pathologic upgrading. The AUC value of the nomogram was 0.893 (95% CI, 0.787-0.999).

CONCLUSION

The combination of PI-RADS v2 and periprostatic fat measured on mp-MRI can help predict pathologic upgrading amongst patients with biopsy Gleason score 3 + 3 PCa.

Pathological and 3 Tesla Volumetric Magnetic Resonance Imaging Predictors of Biochemical Recurrence after Robotic Assisted Radical Prostatectomy: Correlation with Whole Mount Histopathology

PURPOSE

We sought to identify the clinical and magnetic resonance imaging variables predictive of biochemical recurrence after robotic assisted radical prostatectomy in patients who underwent multiparametric 3 Tesla prostate magnetic resonance imaging.

MATERIALS AND METHODS

We performed an institutional review board approved, HIPAA (Health Insurance Portability and Accountability Act) compliant, single arm observational study of 3 Tesla multiparametric magnetic resonance imaging prior to robotic assisted radical prostatectomy from December 2009 to March 2016. Clinical, magnetic resonance imaging and pathological information, and clinical outcomes were compiled. Biochemical recurrence was defined as prostate specific antigen 0.2 ng/cc or greater. Univariate and multivariate regression analysis was performed.

RESULTS

Biochemical recurrence had developed in 62 of the 255 men (24.3%) included in the study at a median followup of 23.5 months. Compared to the subcohort without biochemical recurrence the subcohort with biochemical recurrence had a greater proportion of patients with a high grade biopsy Gleason score, higher preoperative prostate specific antigen (7.4 vs 5.6 ng/ml), intermediate and high D'Amico classifications, larger tumor volume on magnetic resonance imaging (0.66 vs 0.30 ml), higher PI-RADS® (Prostate Imaging-Reporting and Data System) version 2 category lesions, a greater proportion of intermediate and high grade radical prostatectomy Gleason score lesions, higher pathological T3 stage (all p <0.01) and a higher positive surgical margin rate (19.3% vs 7.8%, p = 0.016). On multivariable analysis only tumor volume on magnetic resonance imaging (adjusted OR 1.57, p = 0.016), pathological T stage (adjusted OR 2.26, p = 0.02), positive surgical margin (adjusted OR 5.0, p = 0.004) and radical prostatectomy Gleason score (adjusted OR 2.29, p = 0.004) predicted biochemical recurrence.

CONCLUSIONS

In this cohort tumor volume on magnetic resonance imaging and pathological variables, including Gleason score, staging and positive surgical margins, significantly predicted biochemical recurrence. This suggests an important new imaging biomarker.

Magnetic Resonance Imaging-Based Prostate-Specific Antigen Density for Prediction of Gleason Score Upgrade in Patients With Low-Risk Prostate Cancer on Initial Biopsy

OBJECTIVE

The aim of this study was to assess the utility of prostate-specific antigen density (PSAD) calculated using magnetic resonance imaging for predicting Gleason score (GS) upgrade in patients with low-risk prostate cancer on biopsy.

METHODS

Seventy-three patients were divided into 2 groups according to the concordance between biopsy and prostatectomy GS: group 1 (6/6) and group 2 (6/≥7). Magnetic resonance imaging-based PSAD, prostate volume, prostate-specific antigen (PSA), and age were compared between the 2 groups. Logistic regression and receiver operating characteristic curve analysis were performed.

RESULTS

Gleason score was upgraded in 40 patients. Patients in group 2 had significantly higher PSAD and PSA values and smaller prostate volume than did those in group 1. Prostate-specific antigen density of 0.26 ng/mL per cm or higher, PSA of 7.63 ng/mL or higher, and prostate volume of 25.1 cm or less were related to GS upgrade, with area-under-the-curve values of 0.765, 0.721, and 0.639, respectively.

CONCLUSIONS

Magnetic resonance imaging-based PSAD could help in predicting postoperative GS upgrade in patients with low-risk prostate cancer.

[Indications and limits of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about indications and limits of ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 107 articles were analysed.

RESULTS

The objective to combine reduction of side effects and oncological control has induced recent development of several ablative therapies. Beyond this heterogeneity, some preferential indications appear: unilateral cancer of low risk (but with significant volume, excluding active surveillance) or intermediate risk (excluding majority of grade 4); treatment targeted the index lesion, by quarter or hemi-ablation, based on biopsy and mpMRI. In addition, indications must considered specific limits of each energy, such as gland volume and tumor localization.

CONCLUSION

Based on new imaging and biopsy, ablative therapies will probably increased its role in the future in management of localize prostate cancer. The multiple ongoing trials will certainly be helpful to better define their indications and limits.

Magnetic resonance imaging targeted transperineal prostate biopsy: a local anaesthetic approach

BACKGROUND

Despite high rates of disease misclassification and sepsis, the use of transrectal biopsy remains commonplace. Transperineal mapping biopsies mitigate these problems but carry increased cost and patient burden. Local anaesthetic, multiparametric magnetic resonance imaging (MRI)-targeted transperineal biopsy may offer an alternative. Here, we aim to determine the feasibility, tolerability and detection rates of clinically significant prostate cancer using a local anaesthetic, transperineal, MRI-targeted biopsy technique.

METHODS

Tertiary referral centre in which 181 consecutive men underwent local anaesthetic, transperineal MRI-targeted prostate biopsy (September 2014 to January 2016). A standardized local anaesthetic technique was used to obtain targeted biopsies using visual estimation with the number of targeted cores determined by each of a number of users. We assessed adverse events, patient visual analogue pain scores and detection rates of clinically significant cancer (defined by University College London (UCL) definitions one and two and separately by the presence of dominant and non-dominant Gleason pattern 4). We secondarily assessed detection of any cancer, rates of detection by MRI (Likert) score and by presenting PSA. Differences were assessed using Chi-squared tests (P<0.05).

RESULTS

One hundred eighty-one men with 243 lesions were included. There were no episodes of sepsis or re-admissions and one procedure was abandoned owing to patient discomfort. Twenty-three out of 25 (92%) men would recommend the procedure to another. Median visual analogue pain score was 1.0 (interquartile range: 0.0-2.4). A total 104/181 (57%) had UCL definition 1 disease (Gleason ⩾4+3 and/or maximum cancer length ⩾6 mm) and 129/181 (71%) had UCL definition 2 cancer (Gleason ⩾3+4 and/or maximum cancer length ⩾4 mm). Fifty-four out of 181 (30%) and 124/181 (69%) had dominant and non-dominant pattern 4 disease or greater (irrespective of cancer length). Any cancer was detected in 142/181 (78%). Significant disease was more likely in higher MRI-scoring lesions and in men with PSAs ⩾10 ng ml-1.

CONCLUSIONS

This approach to prostate biopsy is feasible, tolerable and can be performed in ambulatory settings.

Active Surveillance Versus Watchful Waiting for Localized Prostate Cancer: A Model to Inform Decisions

BACKGROUND

An increasing proportion of prostate cancer is being managed conservatively. However, there are no randomized trials or consensus regarding the optimal follow-up strategy.

OBJECTIVE

To compare life expectancy and quality of life between watchful waiting (WW) versus different strategies of active surveillance (AS).

DESIGN, SETTING, AND PARTICIPANTS

A Markov model was created for US men starting at age 50, diagnosed with localized prostate cancer who chose conservative management by WW or AS using different testing protocols (prostate-specific antigen every 3-6 mo, biopsy every 1-5 yr, or magnetic resonance imaging based). Transition probabilities and utilities were obtained from the literature.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Primary outcomes were life years and quality-adjusted life years (QALYs). Secondary outcomes include radical treatment, metastasis, and prostate cancer death.

RESULTS AND LIMITATIONS

All AS strategies yielded more life years compared with WW. Lifetime risks of prostate cancer death and metastasis were, respectively, 5.42% and 6.40% with AS versus 8.72% and 10.30% with WW. AS yielded more QALYs than WW except in cohorts age >65 yr at diagnosis, or when treatment-related complications were long term. The preferred follow-up strategy was also sensitive to whether people value short-term over long-term benefits (time preference). Depending on the AS protocol, 30-41% underwent radical treatment within 10 yr. Extending the surveillance biopsy interval from 1 to 5 yr reduced life years slightly, with a 0.26 difference in QALYs.

CONCLUSIONS

AS extends life more than WW, particularly for men with higher-risk features, but this is partly offset by the decrement in quality of life since many men eventually receive treatment.

PATIENT SUMMARY

More intensive active surveillance protocols extend life more than watchful waiting, but this is partly offset by decrements in quality of life from subsequent treatment.

Pathologic correlation of transperineal in-bore 3-Tesla magnetic resonance imaging-guided prostate biopsy samples with radical prostatectomy specimen

PURPOSE

To determine the accuracy of in-bore transperineal 3-Tesla (T) magnetic resonance (MR) imaging-guided prostate biopsies for predicting final Gleason grades in patients who subsequently underwent radical prostatectomy (RP).

METHODS

A retrospective review of men who underwent transperineal MR imaging-guided prostate biopsy (tpMRGB) with subsequent radical prostatectomy within 1 year was conducted from 2010 to 2015. All patients underwent a baseline 3-T multiparametric MRI (mpMRI) with endorectal coil and were selected for biopsy based on MR findings of a suspicious prostate lesion and high degree of clinical suspicion for cancer. Spearman correlation was performed to assess concordance between tpMRGB and final RP pathology among patients with and without previous transrectal ultrasound (TRUS)-guided biopsies.

RESULTS

A total of 24 men met all eligibility requirements, with a median age of 65 years (interquartile range [IQR] 11.7). The median time from biopsy to RP was 85 days (IQR 50.5). Final pathology revealed Gleason 3 + 4 = 7 in 12 patients, 4 + 3 = 7 in 10 patients, and 4 + 4 = 8 in 2 patients. A strong correlation (ρ: +0.75, p < 0.001) between tpMRGB and RP results was observed, with Gleason scores concordant in 17 cases (71%). 16 of the 24 patients underwent prior TRUS biopsies. Subsequent tpMRGB revealed Gleason upgrading in 88% of cases, which was concordant with RP Gleason scores in 69% of cases (ρ: +0.75, p < 0.001).

CONCLUSION

Final Gleason scores diagnosed by tpMRGB at 3-T correlate strongly with final RP surgical pathology. This may facilitate prostate cancer diagnosis, particularly in patients with negative or low-grade TRUS biopsy results in whom clinically significant cancer is suspected or detected on mpMRI.

The performance of PI-RADSv2 and quantitative apparent diffusion coefficient for predicting confirmatory prostate biopsy findings in patients considered for active surveillance of prostate cancer

PURPOSE

To assess the performance of the updated Prostate Imaging Reporting and Data System (PI-RADSv2) and the apparent diffusion coefficient (ADC) for predicting confirmatory biopsy results in patients considered for active surveillance of prostate cancer (PCA).

METHODS

IRB-approved, retrospective study of 371 consecutive men with clinically low-risk PCA (initial biopsy Gleason score ≤6, prostate-specific antigen <10 ng/ml, clinical stage ≤T2a) who underwent 3T-prostate MRI before confirmatory biopsy. Two independent radiologists recorded the PI-RADSv2 scores and measured the corresponding ADC values in each patient. A composite score was generated to assess the performance of combining PI-RADSv2 + ADC.

RESULTS

PCA was upgraded on confirmatory biopsy in 107/371 (29%) patients. Inter-reader agreement was substantial (PI-RADSv2: k = 0.73; 95% CI [0.66-0.80]; ADC: r = 0.74; 95% CI [0.69-0.79]). Accuracies, sensitivities, specificities, positive predicted value and negative predicted value of PI-RADSv2 were 85, 89, 83, 68, 95 and 78, 82, 76, 58, 91% for ADC. PI-RADSv2 accuracy was significantly higher than that of ADC for predicting biopsy upgrade (p = 0.014). The combined PI-RADSv2 + ADC composite score did not perform better than PI-RADSv2 alone. Obviating biopsy in patients with PI-RADSv2 score ≤3 would have missed Gleason Score upgrade in 12/232 (5%) of patients.

CONCLUSION

PI-RADSv2 was superior to ADC measurements for predicting PCA upgrading on confirmatory biopsy.

From novice to expert: analyzing the learning curve for MRI-transrectal ultrasonography fusion-guided transrectal prostate biopsy

PURPOSE

To investigate the learning curve of a novice in MRI/TRUS software fusion biopsy and to compare his results with the expert standard at our institution.

METHODS

Overall 126 MRI/TRUS fusion-guided transrectal biopsies were performed using an electromagnetic tracking ultrasonography platform. The learning progress of the novice was evaluated comparing his initial 42 procedures (group A) with his following 42 (group B). The institution's expert standard (group C), which was compared to the novice's groups, was defined by the expert's experience of 42 MRI/TRUS fusion biopsies. Primary learning curve parameters were targeted biopsy detection quotient and biopsy time.

RESULTS

Overall detection of prostate cancer was 64% (27/42), 62% (26/42) and 62% (26/42) in groups A, B and C, respectively. The median target biopsy detection quotient significantly increased (p = 0.04) in group B (0.75, interquartile range (IQR) 0.25-1.0) compared to group A. (0.33, IQR 0.2-0.5). Group C revealed a median detection quotient of 0.5 (IQR 0.25-0.76) that did not differ significantly from the novice's groups (p = 0.2). Median biopsy time was significantly higher in group A (45 min, IQR 33-50 min) compared to groups B (25 min, IQR 23-29 min) and C (24 min, IQR 16-46 min) (p < 0.01).

CONCLUSIONS

The present study revealed the individual learning curve of a novice in MRI/TRUS fusion biopsy and demonstrated significant learning progress regarding targeted biopsy detection quotient and biopsy time.

A critical comparison of techniques for MRI-targeted biopsy of the prostate

MRI-targeted biopsy is a promising technique that offers an improved detection of clinically significant prostate cancer over standard non-targeted biopsy. It is established that prostate MRI is of use in both the primary and repeat biopsy setting for the detection of significant prostate cancer. There are three approaches to targeting biopsies to areas of interest seen on prostate MRI. They each rely on the acquisition and reporting of a diagnostic quality multi-parametric MRI scan used to identify areas of interest, and the subsequent use of those diagnostic quality images in combination with real-time images of the prostate during the biopsy procedure. The three techniques are: visual registration of the MRI images with a real-time ultrasound image; software-assisted fusion of the MRI images and the real-time ultrasound images, and in-bore biopsy, which requires registration of a diagnostic quality MRI scan with a real time interventional MRI image. In this paper we compare the three techniques and evaluate those studies where there is a direct comparison of more than one MRI-targeting technique. PubMed was searched from inception to November 2016 using the search terms (cognitive registration OR visual registration OR fusion biopsy OR in-bore biopsy OR targeted biopsy) AND (prostate cancer OR prostate adenocarcinoma OR prostate carcinoma OR prostatic carcinoma OR prostatic adenocarcinoma) AND (MRI OR NMR OR magnetic resonance imaging OR mpMRI OR multiparametric MRI). The initial search included 731 abstracts. Eleven full text papers directly compared two or more techniques of MRI-targeting, and were selected for inclusion. The detection of clinically significant prostate cancer varied from 0% to 93.3% for visual registration, 23.2% to 100% for software-assisted registration and 29% to 80% for in-bore biopsy. Detection rates for clinically significant cancer are dependent on the prevalence of cancer within the population biopsied, which in turn is determined by the selection criteria [biopsy naïve, previous negative biopsy, prostate specific antigen (PSA) selection criteria, presence of a lesion on MRI]. Cancer detection rates varied more between study populations than between biopsy approaches. Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. Although there have been studies supporting each of the three techniques, substantial differences in methodology and reporting the findings make it difficult to reliably compare their outcomes.

Role of prostate magnetic resonance imaging in active surveillance

Active surveillance (AS) has emerged as a beneficial strategy for management of low risk prostate cancer (PCa) and prevention of overtreatment of indolent disease. However, selection of patients for AS using traditional 12-core transrectal prostate biopsy is prone to sampling error and presents a challenge for accurate risk stratification. In fact, around a third of men are upgraded on repeat biopsy which disqualifies them as appropriate AS candidates. This uncertainty affects adoption of AS among patients and physicians, leading to current AS protocols involving repetitive prostate biopsies and unclear triggers for progression to definitive treatment. Prostate magnetic resonance imaging (MRI) has the potential to overcome some of these limitations through localization of significant tumors in the prostate. In conjunction with MRI-targeted prostate biopsy, improved sampling and detection of clinically significant PCa can help streamline the process of selecting suitable men for AS and early exclusion of men who require definitive treatment. MRI can also help minimize the invasive nature of monitoring for disease progression while on AS. Men with stable MRI findings have high negative predictive value for Gleason upgrade on subsequently biopsy, suggesting that men may potentially be monitored by serial MRI examinations with biopsy reserved for significant changes on imaging. Targeted biopsy on AS also allows for specific sampling of concerning lesions, although further data is necessary to evaluate the relative contribution of systematic and targeted biopsy in detecting the 25-30% of men who progress on AS. Further research is also warranted to better understand the nature of clinically significant cancers that are missed on MRI and why certain men have progression of disease that is not visible on prostate MRI. Consensus is also needed over what constitutes progression on MRI, when prostate biopsy can be safely avoided, and how to best utilize this additional information in current AS protocols. Despite these challenges, prostate MRI, either alone or in conjunction with MRI-targeted prostate biopsy, has the potential to significantly improve our current AS paradigm and rates of AS adoption among patients moving forward.

MR/US Fusion Technology: What Makes It Tick?

MR/US fusion biopsy has emerged as a significant refinement of traditional prostate cancer diagnostic techniques. Utilizing not only quantitative imaging suspicion information from mpMRI but also the spatial accuracy and three-dimensional localization allows such strategies to specifically sample areas of concern with the gland. As such, diagnostic certainty is markedly improved. In this manuscript, we aim to highlight the multidisciplinary approach (amongst urologists, radiologists, pathologists, imaging technologists, nursing staff, and patients) which is required to launch and maintain a successful prostate imaging program.

[Role of prostate MRI, TRUS fusion biopsies and new markers in the diagnostic strategy of prostate cancer]

Multiparametric MRI prostate (mp-MRI) is a powerful tool to locate lesions>0.5cm³ (below this threshold tumor volume, prostate cancers are classified as "insignificant"). The detection rate of the mp-MRI for significant cancers of small volume (0.5-1cm³) with a Gleason score≥7 is>85 %. The prostate mp-MRI optimizes the management of cancers classified as low risk of progression by providing aggressive criteria for misclassified lesions, which require an active treatment and enhance the clinicopathological criteria of indolence for subclinical lesions, which can justify of surveillance. MRI-mp coupled to the 3D ultrasound image fusion, optimizes the predictive value of biopsies and improves tumor staging, particularly when benign prostatic hyperplasia (>40cm³) is associated with clinical course. New tissue markers feasible on biopsies allow to define better the risk of progression of the small volume of cancer in order to reinforce the indications of surveillance or delayed curative treatment.

Role of MRI in the Risk Assessment of Primary Prostate Cancer

A successful paradigm shift toward personalized management strategies for patients with prostate cancer (PCa) is heavily dependent on the availability of noninvasive diagnostic tools capable of accurately establishing the true extent of disease at the time of diagnosis and estimating the risk of subsequent disease progression and related mortality. Although there is still considerable scope for improvement in its diagnostic, predictive, and prognostic capabilities, multiparametric prostate magnetic resonance imaging (MRI) is currently regarded as the imaging modality of choice for local staging of PCa. A negative MRI, that is, the absence of any MRI-visible intraprostatic lesion, has a high negative predictive value for the presence of clinically significant PCa and can substantiate the consideration of active surveillance as a preferred initial management approach. MRI-derived quantitative and semi-quantitative parameters can be utilized to noninvasively characterize MRI-visible prostate lesions and identify those patients who are most likely to benefit from radical treatment, and differentiate them from patients with benign or indolent prostate pathology that may also be visible on MRI. This literature review summarizes current strategies how MRI can be used to determine a tailored management strategy for an individual patient.