Value of 3-T Multiparametric Magnetic Resonance Imaging and Magnetic Resonance–Guided Biopsy for Early Risk Restratification in Active Surveillance of Low-Risk Prostate Cancer: A Prospective Multicenter Cohort Study

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.

Magnetic Resonance Imaging-guided Active Surveillance Without Annual Rebiopsy in Patients with Grade Group 1 or 2 Prostate Cancer: The Prospective PROMM-AS Study

Background

Multiparametric magnetic resonance imaging (mpMRI) may allow patients with prostate cancer (PC) on active surveillance (AS) to avoid repeat prostate biopsies during monitoring.

Objective

To assess the ability of mpMRI to reduce guideline-mandated biopsy and to predict grade group upgrading in patients with International Society of Urological Pathology grade group (GG) 1 or GG 2 PC using Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) scores. The hypothesis was that the AS disqualification rate (ASDQ) rate could be reduced to 15%.

Design setting and participants

PROMM-AS was a prospective study assessing 2-yr outcomes for an mpMRI-guided AS protocol. A 12 mo after AS inclusion on the basis of MRI/transrectal ultrasound fusion-guided biopsy (FBx), all patients underwent mpMRI. For patients with stable mpMRI (PRECISE 1-3), repeat biopsy was deferred and follow-up mpMRI was scheduled for 12 mo later. Patients with mpMRI progression (PRECISE 4-5) underwent FBx. At the end of the study, follow-up FBx was indicated for all patients.

Outcome measurements and statistical analysis

We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for upgrading to GG 2 in the GG 1 group, and to GG 3 in the GG 2 group on MRI. We performed regression analyses that included clinical variables.

Results and limitations

The study included 101 patients with PC (60 GG 1 and 41 GG 2). Histopathological progression occurred in 31 patients, 18 in the GG 1 group and 13 in the GG 2 group. Thus, the aim of reducing the ASDQ rate to 15% was not achieved. The sensitivity, specificity, PPV, and NPV for PRECISE scoring of MRI were 94%, 64%, 81%, and 88% in the GG 1 group, and 92%, 50%, 92%, and 50%, respectively, in the GG 2 group. On regression analysis, initial prostate-specific antigen (p < 0.001) and higher PRECISE score (4-5; p = 0.005) were significant predictors of histological progression of GG 1 PC. Higher PRECISE score (p = 0.009), initial Prostate Imaging-Reporting and Data System score (p = 0.009), previous negative biopsy (p = 0.02), and percentage Gleason pattern 4 (p = 0.04) were significant predictors of histological progression of GG 2 PC. Limitations include extensive MRI reading experience, the small sample size, and limited follow-up.

Conclusions

MRI-guided monitoring of patients on AS using PRECISE scores avoided unnecessary follow-up biopsies in 88% of patients with GG 1 PC and predicted upgrading during 2-yr follow-up in both GG 1 and GG 2 PC.

Patient summary

We investigated whether MRI (magnetic resonance imaging) scores can be used to guide whether patients with lower-risk prostate cancer who are on active surveillance (AS) need to undergo repeat biopsies. Follow-up biopsy was deferred for 1 year for patients with a stable score and performed for patients whose score progressed. After 24 months on AS, all men underwent MRI and biopsy. Among patients with grade group 1 cancer and a stable MRI score, 88% avoided biopsy. For patients with MRI score progression, AS termination was correctly recommended in 81% of grade group 1 and 92% of grade group 2 cases.

Clinical Relevance of Circulating Tumor Cells in Prostate Cancer Management

Given the low specificity of the routinely used biomarker prostate-specific antigen, circulating tumor cell (CTC) enumeration seems to be particularly useful in the monitoring of prostate cancer. In this review, we focused on a few aspects of CTC enumeration in prostate malignancies: prognostic value in metastatic and non-metastatic tumors, role in the monitoring of treatment outcomes, use as a surrogate marker for survival, and other applications, mostly for research purposes. CTC enumeration, without a doubt, offers an attractive perspective in the management of prostate cancer. However, the vast majority of available data about the role of CTC in this malignancy originate from randomized studies of anticancer agents and do not necessarily translate into real-world clinical practice. Further, most studies on the application of CTC in prostate cancer patients were limited to advanced stages of this malignancy. Meanwhile, the role of CTC in the early stages of prostate cancer, in which some patients may present with occult disseminated disease, is still relatively poorly understood, and should thus be studied extensively. Other obstacles in the widespread application of CTC enumeration in routine clinical practice include considerable discrepancies in the number of cells determined with various commercially available systems.

Use of multiparametric magnetic resonance imaging (mpMRI) in active surveillance for low-risk prostate cancer: a scoping review on the benefits and harm of mpMRI in different biopsy scenarios

BACKGROUND

There is uncertainty on how multiparametric MRI (mpMRI) and MRI-targeted biopsy (MRI-TB) can be best used to manage low-risk prostate cancer patients on Active Surveillance (AS). We performed a scoping review to evaluate the benefits and harm associated with four different biopsy scenarios in which mpMRI can be implemented in AS.

METHODS

Medline, Embase and Cochrane Library databases (1 January 2013-18 September 2020) were searched. Included studies were on men with low-risk prostate cancer enrolled in AS, who had mpMRI ± MRI-TB and standard prostate biopsy (systematic transrectal ultrasound or transperineal saturation biopsy), at confirmatory or follow-up biopsy. Primary outcomes were the number of Gleason score upgrades and biopsies avoided.

RESULTS

Eight confirmatory biopsy studies and three follow-up biopsy studies were included. Compared to the benchmark of using standard biopsy (SB) for all men, the addition of MRI-TB increased the detection of Gleason score upgrades at both confirmatory (6/8 studies) and follow-up biopsy (3/3 studies), with increments of 1.7-11.8 upgrades per 100 men. 6/7 studies suggested that the use of a positive mpMRI to triage men for MRI-TB or SB alone would detect fewer Gleason score upgrades than benchmark at confirmatory biopsy, but the combination of MRI-TB and SB would detect more upgrades than the benchmark. For follow-up biopsy, the evidence on mpMRI triage biopsy scenarios was inconclusive due to the small number of included studies.

CONCLUSIONS

The addition of MRI-TB to benchmark (SB for all men) maximises the detection of Gleason score upgrades at confirmatory and follow-up biopsy. When the use of mpMRI to triage men for a biopsy is desired, the combination of MRI-TB and SB should be considered for men with positive mpMRI at confirmatory biopsy. The evidence on mpMRI triage scenarios was inconclusive in the follow-up biopsy setting.

The role of multiparametric magnetic resonance imaging in the selection and follow-up of patients undergoing active surveillance for prostate cancer. An European Section of Uro-Technology (ESUT) review

INTRODUCTION

In recent years, active surveillance (AS) has gained popularity as a safe and reasonable option for patients with low-risk, clinically localized prostate cancer.

OBJECTIVE

To summarize the latest information regarding the use of mpMRI in the setting of active surveillance (AS) for the management of prostate cancer (PCa).

EVIDENCE ACQUISITION

A PubMed-based, English literature search was conducted through February 2020. We selected the most relevant original articles, meta-analyses and systematic reviews that could provide important information.

EVIDENCE SYNTHESIS

The great importance of mpMRI of the prostate in the setting of PCa diagnosis is its ability to visualize primarily high-grade cancerous lesions potentially missed on systematic biopsies. In several studies, mpMRI has shown an improved performance over clinically based models for identifying candidates which will benefit the most from AS. Although data on prostate mpMRI during follow-up of men under AS is sparse, it holds the probability to improve significantly AS programs by a more precise selection of optimal candidates, a more accurate identification of disease progression and a reduction in number of biopsies. The goal of reassessment of patients undergoing AS is to find the most effective moment to change attitude to active treatment.

CONCLUSION

The value of mpMRI has been recognized due to its high negative predictive value (NPV) for lesion upgrading in low-risk PCa patients. The improvement in imaging detection, and precise diagnosis with mpMRI could reduce misclassifications at initial diagnosis and during follow-up, reducing the number of biopsies.

In-Bore MRI-guided Prostate Biopsies in Patients with Prior Positive Transrectal US-guided Biopsy Results: Pathologic Outcomes and Predictors of Missed Cancers

Purpose

To evaluate the role of confirmatory in-bore MRI-guided biopsy in patients with low- or intermediate-risk disease diagnosed at prior transrectal US-guided biopsy and to evaluate the rate and predictors for missed cancers.

Materials and Methods

A retrospective evaluation of 50 consecutive men who had previously undergone transrectal US-guided biopsy with positive results and who underwent subsequent in-bore MRI-guided biopsy at our university hospital (average time interval, 11 months) between 2012 and 2016 was performed. Ten men were excluded because of a history of treatment after transrectal US-guided biopsy. A total of 40 men (mean age, 63 years; range, 47-84 years) were included in this study. Multiparametric 3-T MRI (T2-weighted, diffusion-weighted, and dynamic contrast material-enhanced) and transrectal in-bore MRI-guided biopsy were performed. Cancer detection, disease-grade changes, and cancers missed at in-bore MRI-guided biopsy were evaluated. Descriptive statistics were used to report different rates. The Fisher exact test was used for categoric variables. The Mann-Whitney U test and independent Student t test were used for nonparametric and parametric data, respectively. The McNemar test was used for paired data.

Results

The overall cancer detection rate when using in-bore MRI-guided biopsy was 65% (26 of 40). In-bore MRI-guided biopsy detected 14 previously undiscovered cancerous lesions (clinically significant cancers [CSCs], 57.1% [eight of 14]). An overall disease upgrade by in-bore MRI-guided biopsy occurred in 40% (16 of 40) of cases (61.5% [16 of 26] of cases with positive results from in-bore MRI-guided biopsy). One case was downgraded from a Gleason score (GS) of 3 + 4 = 7 to a GS of 3 + 3 = 6. Out of 71 sextant biopsies with positive results detected by transrectal US-guided biopsy (from all 40 patients), 80% (57 of 71) were visible on MR images (in-bore MRI-guided biopsy results were positive in 52.6% [30 of 57]), and 20% (14 of 71) had no image correlates on MR images. In-bore MRI-guided biopsy upgraded 60% (18 of 30) and downgraded 3.3% (one of 30) of detected lesions. The false-negative rate was 35% (14.2% [two of 14] of patients had CSCs; GS ≥ 7), was higher in prostate volumes of greater than 40 mL, and was lower in the anterior gland location (P = .04 and .01, respectively).

Conclusion

Performing confirmatory in-bore MRI-guided biopsy following positive transrectal US-guided biopsy resulted in a high disease-upgrade incidence with subsequently improved disease-risk stratification, particularly when considering patients for active surveillance or focal therapy. Supplemental material is available for this article. © RSNA, 2020See also the commentary by Weiss and Solomon in this issue.

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%.

Multiparametric magnetic resonance imaging ultrasound-guided fusion biopsy during active surveillance: A single-centre study

Objective

To analyse the role of multiparametric magnetic resonance imaging (mpMRI) ultrasound (US)-guided fusion biopsy (FB) in patients with low-risk prostate cancer (PCa) under active surveillance (AS).

Patients and methods

Our retrospective study included 47 patients under AS who consecutively underwent both FB and standard biopsy (SB), from May 2015 until November 2017. We defined FB as a transrectal US-guided biopsy based on mpMRI. The primary endpoint was to assess the rate of concordance between FB and SB in terms of diagnostic yield, as well as the rate of Gleason Score upgrading/downgrading between the two techniques. Cohen’s kappa coefficient (κ) was applied to test the concordance between FB and SB.

Results

The median (interquartile range [IQR]) follow-up was 20 (13–37) months. The median (IQR) number of cores taken was 13 (12–14) at SB and 4 (4–6) at FB. Overall, FB missed 12/47 (26%) PCa diagnoses compared to SB. There was concordance between SB and FB in 64% of the patients. The κ showed a perfect agreement between SB and FB for the detection of PCa with Gleason Score 4 + 4 and a weak concordance for negative biopsies (κ: 0.46) and for PCa with a Gleason Score 4 + 3 (κ: 0.54). There was Gleason Score upgrading at FB in two of 47 (4%) patients, whereas there was downgrading in three of 47 (6%) patients.

Conclusion

In our present study, FB showed no superiority over SB for the detection of PCa. On the contrary, FB had a high rate of missed PCa compared to SB. Further studies are required to ascertain the role of FB in AS.

Abbreviations

AS: active surveillance; FB: fusion biopsy; IL: index lesion; IQR: interquartile range; mpMRI: multiparametric MRI; (cs)PCa: (clinically significant) prostate cancer; PI-RADS: Prostate Imaging-Reporting and Data System; PRIAS: Prostate Cancer Research International Active Surveillance; ROI: region of interest; SB: standard biopsy

Development and External Validation of Multiparametric MRI-Derived Nomogram to Predict Risk of Pathologic Upgrade in Patients on Active Surveillance for Prostate Cancer

OBJECTIVE. The aim of this study was to create, develop, and externally validate a nomogram that predicts pathologic upgrade in patients on active surveillance (AS) for prostate cancer using commonly available clinical and multiparametric MRI (mpMRI) factors. MATERIALS AND METHODS. A consecutive sample of 300 patients undergoing AS for prostate cancer at the Keimyung University Dongsan Hospital between 2010 and 2016 was used to develop the nomogram. The validation cohort consisted of 150 patients undergoing active surveillance at Kyungpook National University Hospital between 2013 and 2017. The study outcome was the occurrence of pathologic upgrade in AS patients. The relationship between the clinical and mpMRI factors considered and pathologic upgrade was tested using univariate and multivariate logistic regression analyses. The predictive accuracy of the nomogram was determined using the ROC AUC. RESULTS. The overall rate of pathologic upgrade was 25.0% in the developmental cohort and 22.0% in the validation cohort. Significant variables in the models were age, prostate-specific antigen level, biopsy grade group 2, baseline Prostate Imaging Reporting and Data System (PI-RADS) scores of 4 and 5, positive cores on initial biopsy greater than 1, and biopsy cores with 50% or more tumor involvement. The progression seen on mpMRI of PI-RADS score was significantly associated with pathologic upgrade. The nomogram used to predict the risk of pathologic upgrade had a predictive accuracy of 0.78 in the external validation cohort. CONCLUSION. This study developed and externally validated a nomogram that predicts the risk of pathologic upgrade on the basis of commonly used factors. This nomogram may be used to assist management decision making for patients on AS for prostate cancer.

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.

Magnetic resonance imaging-guided targeted biopsy in risk classification among patients on active surveillance: A diagnostic meta-analysis

BACKGROUND

The aim of this study was to assess the sensitivity and accuracy of magnetic resonance imaging-guided targeted biopsy (MRI-TB) in patients undergoing active surveillance (AS) procedure.

METHODS

We searched databases to identify relevant studies which compared MRI-TB with systemic biopsy for diagnosing prostate cancer in patients on AS. Outcomes included sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the curve (AUC) and publication bias of AS group, confirmatory biopsy group and follow-up biopsy group.

RESULTS

Fourteen articles involving 1693 patients were included. In AS group, the sensitivity was 0.62 (95% confidence interval [CI], 0.57-0.68), specificity was 0.89 (95% CI, 0.87-0.90), NLR was 0.43 (0.31-0.60), PLR was 4.90 (3.50-6.86), DOR was 12.75 (7.22-22.51), and AUC was 0.8645. In confirmatory biopsy group, the sensitivity was 0.67 (0.59-0.74), specificity was 0.89 (0.86-0.91), NLR was 0.42 (0.27-0.65), PLR was 4.94 (3.88-6.30), DOR was 14.54 (9.60-22.02), and AUC was 0.8812. In follow-up biopsy group, the sensitivity was 0.35 (0.22-0.51), specificity was 0.88 (0.82-0.92), NLR was 0.76 (0.52-1.11), PLR was 3.06 (1.71-5.50), DOR was 4.41 (2.15-9.03), and AUC was 0.8367.

CONCLUSION

MRI-TB has a moderate-to-high diagnostic accuracy for diagnosing and reclassifying patients on AS with high specificity and AUC value under the SROC curve.

Outcomes of Serial Multiparametric Magnetic Resonance Imaging and Subsequent Biopsy in Men with Low-risk Prostate Cancer Managed with Active Surveillance

BACKGROUND

Outcomes of serial multiparametric magnetic resonance imaging (mpMRI) and subsequent biopsy in monitoring prostate cancer (PCa) in men on active surveillance (AS) have not been defined clearly.

OBJECTIVE

To determine whether changes in serial mpMRI can predict pathological upgrade among men with grade group (GG) 1 PCa managed with AS.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of men with GG1 on AS with at least two consecutive mpMRI examinations during 2012-2018 who underwent mpMRI/ultrasound fusion or systematic biopsies.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Progression on serial mpMRI was evaluated as a predictor of pathological upgrading to GG≥2 on a follow-up biopsy using clinical, pathological, and imaging factors in binary logistic regression. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were determined.

RESULTS AND LIMITATIONS

Of 122 patients, 29 men (23.8%) experienced pathological upgrade on the follow-up biopsy. Progression on mpMRI was not associated with pathological upgrade. The sensitivity, specificity, PPV, and NPV of mpMRI progression for predicting pathological upgrade were 41.3%, 54.8%, 22.2%, and 75%, respectively. Age (odds ratio [OR] 1.17, p=0.006), Prostate Imaging Reporting and Data System (PI-RADS) score on initial mpMRI (4-5 vs ≤3, OR 7.48, p=0.01), number of positive systematic cores (OR 1.84, p=0.03), number of positive targeted cores (OR 0.44, p=0.04), and maximum percent of targeted core tumor involvement (OR 1.04, p=0.01) were significantly associated with pathological upgrade.

CONCLUSIONS

We did not observe an association between mpMRI progression and pathological upgrade; however, a PI-RADS score of 4-5 on initial mpMRI was predictive of subsequent pathological progression. The continued use of systematic and fusion biopsies appears necessary due to risks of reclassification over time.

PATIENT SUMMARY

Progression on serial multiparametric magnetic resonance imaging during active surveillance (AS) is not associated with progression on the follow-up biopsy. Both systematic and fusion biopsies are necessary to sufficiently capture progression during AS.

Prostate MRI using an external phased array wearable pelvic coil at 3T: comparison with an endorectal coil

PURPOSE

To evaluate T2w and DWI image quality using a wearable pelvic coil (WPC) compared with an endorectal coil (ERC).

METHODS

Twenty men consecutively presenting to our prostate cancer MRI clinic were prospectively consented to be scanned using a wearable pelvic coil then an endorectal coil and pelvic phased array coil at 3T. Eighteen patients were suitable for inclusion. Axial T2w images were obtained using the WPC and ERC, and DWI images were obtained using the WPC, ERC, and PPA. Analysis was performed in consensus by two readers with experience in prostate MRI. The readers scored the T2w images using six qualitative criteria and the DWI images using five criteria. Signal-to-noise ratio (SNR) was also measured.

RESULTS

T2w artifact severity was greater for an ERC than a WPC (p = 0.003). There was no significant difference in T2w qualititatve image quality by other measures. The distinction of zonal anatomy on DWI was superior for an ERC compared with both a WPC and a PPA (p = 0.018 and p < 0.001 respectively), and there was no significant difference in DWI image quality by other measures. SNR was significantly higher for ERC imaging for both T2w and DWI.

CONCLUSION

WPC imaging provides comparable image quality to that of an ERC, potentially reducing the need for an ERC. WPC imaging shows reduced T2w artifact severity and inferior DWI zonal anatomy distinction compared with an ERC. Imaging with a WPC produces a lower SNR than an ERC.

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.

Immediate treatment vs. active-surveillance in very-low-risk prostate cancer: the role of patient-, tumour-, and hospital-related factors

BACKGROUND

To provide insight in the treatment variation of very-low-risk prostate cancer patients and to assess the role of hospital-related factors.

METHODS

All patients diagnosed with very-low-risk prostate cancer (cT1c-cT2a, PSA < 10 ng/ml, Gleason score <7 and <3 positive cores) in 2015 and 2016 were identified through the population-based Netherlands Cancer Registry. Multilevel logistic regression analyses were performed to examine the crude and case-mix adjusted probability of immediate treatment vs. active-surveillance (AS) according to hospital of diagnosis and to evaluate the effect of patient-, tumour-, and hospital-related factors.

RESULTS

In all, 2047 (85.4%) of the 2396 patients with very-low-risk prostate cancer were managed with AS. The crude proportion of patients with AS varied from 33.3 to 100% between hospitals. Case-mix adjusted probability varied from 71 to 97%. Tumour stage cT2a vs. cT1c (OR 2.0, 95%CI 1.1-3.6), two vs. one positive core (OR 2.8, 95%CI 1.6-4.7), diagnostic MRI (OR 2.8, 95%CI 1.5-5.2), discussion of a patient in a multi-disciplinary team (OR 2.2, 95%CI 1.1-4.5), discussion of treatment options with the patient (OR 3.3, 95%CI 1.5-7.4) and type of hospital (non-university referral hospital vs. community hospital: OR 0.5, 95%CI 0.2-0.9) were associated with immediate treatment.

CONCLUSION

The majority of Dutch very-low-risk prostate cancer patients is managed with AS but variation between hospitals exists. Part of the variation is explained by patient- and tumour characteristics but also hospital-related factors play a role. This implies that clinical practice could be improved.

Risk of upgrading from prostate biopsy to radical prostatectomy pathology: Is magnetic resonance imaging-guided biopsy more accurate?

Background: This study compared magnetic resonance imaging-guided biopsy (MRI-GB) and transrectal ultrasound guided biopsy (TRUS-GB) with the final histology of the radical prostatectomy (RP) specimen.

Methods: Our subjects were 229 patients with prostate cancer (PCa), proven histopathologically using MRI-GB or TRUS-GB, who underwent RP at our center between December 2015 and December 2016. The main group included 92 patients who underwent MRI-GB and the control group included 137 patients who underwent 12-core TRUS-GB. Histological findings for RP specimens were compared with those from biopsies. We also evaluated predictors of upgraded Gleason score (GS), using uni- and multivariate analyses.

Results: Upgraded GS between biopsy and RP specimen occurred to 22.7% (52/229) of the cohort overall. In univariate analysis, prostate-specific antigen density (PSAD) (P<0.001), prostate volume (PV) < 30 ml (P<0.001), biopsy modality (P=0.027), biopsy GS (P=0.032) and measured MRI lymph node metastasis (P=0.018) were prognostic factors. Multivariate logistic regression analysis showed PV < 30 ml (P<0.001) and biopsy modality (P=0.001) were independent predictors of upgraded GS.

Conclusions: MRI-GB may enhance the diagnostic accuracy of prostate cancer detection in final histopathology with lower rate of upgraded GS than TRUS-GB. Also, PV < 30 ml and biopsy modality were independent predictors of upgraded GS.

MRI findings guiding selection of active surveillance for prostate cancer: a review of emerging evidence

Active surveillance (AS) for prostate cancer (PCa) is generally considered to be a safe strategy for men with low-risk, localized disease. However, as many as 1 in 4 patients may be incorrectly classified as AS-eligible using traditional inclusion criteria. The use of multiparametric magnetic resonance imaging (mpMRI) may offer improved risk stratification in both the initial diagnostic and disease monitoring setting. We performed a review of recently published studies to evaluate the utility of this imaging modality for this clinical setting. An English literature search was conducted on PubMed for original investigations on localized PCa, AS, and magnetic resonance imaging. Our Boolean criteria included the following terms: PCa, AS, imaging, MRI, mpMRI, prospective, retrospective, and comparative. Our search excluded publication types such as comments, editorials, guidelines, reviews, or interviews. Our literature review identified 71 original investigations. Among these, 52 met our inclusion criteria. Evidence suggests mpMRI improves characterization of clinically significant prostate cancer (csPCa) foci, and the enhanced detection and risk-stratification afforded by this modality may keep men from being inappropriately placed on AS. Use of serial mpMRI may also permit longer intervals between confirmatory biopsies. Multiple studies demonstrate the benefit of MRI-targeted biopsies. The use of mpMRI of the prostate offers improved confidence in risk-stratification for men with clinically low-risk PCa considering AS. While on AS, serial mpMRI and MRI-targeted biopsy aid in the detection of aggressive disease transformation or foci of clinically-significant cancer undetected on prior biopsy sessions.

Prostate cancer: in-bore magnetic resonance guided biopsies at active surveillance inclusion improve selection of patients for active treatment

Background Active surveillance (AS) of low-risk prostate cancer (PCa) is an accepted alternative to active treatment. However, the conventional diagnostic trans-rectal ultrasound guided biopsies (TRUS-bx) underestimate PCa aggressiveness in almost half of the cases, when compared with the surgical specimen. Purpose To investigate if additional multi-parametric magnetic resonance imaging (mpMRI) of the prostate and MRI-guided in-bore biopsies (MRGB) at AS inclusion would improve selection of patients for active treatment. Material and Methods All patients enrolled in AS programs at two Danish centers, from October 2014 to January 2016, were offered an mpMRI 8-12 weeks after the initial diagnostic TRUS-bx. Candidates had low-risk disease (PSA < 10 ng/mL, <cT2b, Gleason score [GS] < 7). Prostate lesions were scored on the five-point PIRADS scale (version 1 and 2). MRGB were performed on PIRADS 4 or 5 lesions. Significant cancer was defined as GS > 6 or GS 6 (3 + 3) lesions with ≥ 6 mm maximal cancer core length (MCCL). Results A total of 78 patients were included and in 21 patients a total of 22 PIRADS-score 4 or 5 lesions were detected. MRGB pathology revealed that 17 (81%) of these and 22% of the entire AS population harbored significant cancers at AS inclusion. In eight (38%) cases, the GS was upgraded. Also, nine patients (43%) had GS 6 (3 + 3) foci with MCCL ≥ 6 mm. Conclusion In an AS cohort based on TRUS and TRUS-bx diagnostic strategies, supplemental mpMRI and in-bore MRGB were able to efficiently reclassify a substantial number of patients as candidates for immediate active treatment.

Multiparametric Magnetic Resonance Imaging of the Prostate: Repeatability of Volume and Apparent Diffusion Coefficient Quantification

OBJECTIVES

The aim of this study was to evaluate the repeatability of a region of interest (ROI) volume and mean apparent diffusion coefficient (ADC) in standard-of-care 3 T multiparametric magnetic resonance imaging (mpMRI) of the prostate obtained with the use of endorectal coil.

MATERIALS AND METHODS

This prospective study was Health Insurance Portability and Accountability Act compliant, with institutional review board approval and written informed consent. Men with confirmed or suspected treatment-naive prostate cancer scheduled for mpMRI were offered a repeat mpMRI within 2 weeks. Regions of interest corresponding to the whole prostate gland, the entire peripheral zone (PZ), normal PZ, and suspected tumor ROI (tROI) on axial T2-weighted, dynamic contrast-enhanced subtract, and ADC images were annotated and assessed using Prostate Imaging Reporting and Data System (PI-RADS) v2. Repeatability of the ROI volume for each of the analyzed image types and mean ROI ADC was summarized with repeatability coefficient (RC) and RC%.

RESULTS

A total of 189 subjects were approached to participate in the study. Of 40 patients that gave initial agreement, 15 men underwent 2 mpMRI examinations and completed the study. Peripheral zone tROIs were identified in 11 subjects. Tumor ROI volume was less than 0.5 mL in 8 of 11 subjects. PI-RADS categories were identical between baseline-repeat studies in 11/15 subjects and differed by 1 point in 4/15. Peripheral zone tROI volume RC (RC%) was 233 mm (71%) on axial T2-weighted, 422 mm (112%) on ADC, and 488 mm (119%) on dynamic contrast-enhanced subtract. Apparent diffusion coefficient ROI mean RC (RC%) were 447 × 10 mm/s (42%) in PZ tROI and 471 × 10 mm/s (30%) in normal PZ. Significant difference in repeatability of the tROI volume across series was observed (P < 0.005). The mean ADC RC% was lower than volume RC% for tROI ADC (P < 0.05).

CONCLUSIONS

PI-RADS v2 overall assessment was highly repeatable. Multiparametric magnetic resonance imaging sequences differ in volume measurement repeatability. The mean tROI ADC is more repeatable compared with tROI volume in ADC. Repeatability of prostate ADC is comparable with that in other abdominal organs.

In-bore MRI-guided biopsy: can it optimize the need for periodic biopsies in prostate cancer patients undergoing active surveillance? A pilot test-retest reliability study

OBJECTIVE

To evaluate the test-retest reliability of repeated in-bore MRI-guided prostate biopsy (MRGB).

METHODS

19 lesions in 7 patients who had consecutive MRGBs were retrospectively analysed. Five patients had 2 consecutive MRGBs and two patients had 3 consecutive MRGBs. Both multiparametric MRI and MRGBs were performed using a 3T MRI scanner. Pathology results were categorized into benign, suspicious and malignant. Consistency between first and subsequent biopsy results were analysed as well as the negative predictive value (NPV) for prostate cancer.

RESULTS

15 lesions (≈79%) had matching second biopsy and 4 (21%) had non-matching second biopsy. Lesions with both Prostate Imaging - Reporting and Data System(PIRADS) categories 1 and 4 were all benign and had matching pathology results. Lesions with non-matching results had PIRADS categories 2, 3 and 5. NPV for prostate cancer in first biopsy was 87.5%. Overall agreement was 78.9% and overall disagreement was 21.1%.κ = 0.55 denoting moderate agreement (p = 0.002). 10/19 lesions had a third biopsy session. 9/10 (90%) had matching pathology results across the three biopsy sessions and all matching lesions were benign.

CONCLUSION

In-bore MRI-guided prostate biopsy may have a better reliability for repeat biopsies compared to TRUS biopsy. Final conclusion awaits a prospective analysis on a larger cohort of patients. Advances in knowledge: This pilot study showed that repeated prostate in-bore MRI-guided prostate biopsy may have better reliability compared to TRUS biopsy with a suggested high NPV.

Value of Serial Multiparametric Magnetic Resonance Imaging and Magnetic Resonance Imaging-guided Biopsies in Men with Low-risk Prostate Cancer on Active Surveillance After 1 Yr Follow-up

BACKGROUND

Active surveillance (AS) aims to reduce overtreatment of low-risk prostate cancer (PC). Incorporating multiparametric magnetic resonance imaging (mp-MRI) and MR-guided biopsy (MRGB) in an AS protocol might contribute to more accurate identification of AS candidates.

OBJECTIVE

To evaluate the value of 3T mp-MRI and MRGB in PC patients on AS at inclusion and after 12-mo follow-up.

DESIGN, SETTING, AND PARTICIPANTS

Patients with cT1c-cT2 PC, prostate-specific antigen (PSA) ≤10ng/ml, PSA density <0.2ng/ml/ml, and Gleason scores (GSs) of ≤6 and ≤2 positive biopsy cores were included and followed in an AS protocol including mp-MRI and MRGB. The mp-MRI and MRGB were performed at <3 and 12 mo after diagnosis. Reclassification was defined as GS >6, >2 positive cores at repeat transrectal ultrasound-guided biopsy (TRUSGB), presence of PC in >3 separate cancer foci upon both MRGB and TRUSGB, or cT3 tumor on mp-MRI.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Reclassification rates, treatment after discontinuation, and outcome on radical prostatectomy after discontinuing AS were reported. Uni- and multivariate analyses were performed to identify predictors of reclassification after 1 yr.

RESULTS AND LIMITATIONS

From 2009 to 2013, a total of 111 of 158 patients were consecutively and prospectively included. Around initial diagnosis, 36 patients were excluded from the study protocol; mp-MRI+MRGB reclassified 25/111 (23%) patients, and 11 patients were excluded at own request. Reasons for reclassification were as follows: GS upgrade (15/25, 60%); cT3 disease (3/25, 12%); suspicion of bone metastases (1/25, 4%); and multifocal disease upon MRGB (6/25, 24%). Repeat examinations after 1 yr showed reclassification in 33/75 patients (44%). Reasons were the following: GS upgrade upon TRUSGB (9/33, 27%); volume progression upon TRUSGB (9/33, 27%); cT3 disease upon mp-MRI (1/33, 3%); GS upgrade upon MRGB (1/33, 3%); volume progression upon MRGB (1/33, 3%); multifocal disease upon MRGB (2/33, 6%); and upgrade or upstage upon both TRUSGB and MRGB (10/33, 30%). On logistic regression analysis, the presence of cancer at initial mp-MRI and MRGB examinations was the only predictor of reclassification after 1 yr (odds ratio 5.9, 95% confidence interval 2.0-17.6).

CONCLUSIONS

Although mp-MRI and MRGB are of additional value in the evaluation of PC patients on AS, the value of mp-MRI after 1 yr was limited. As a considerable percentage of GS ≥7 PC after 1 yr was detected only by TRUSGB, TRUSGB cannot be omitted yet.

PATIENT SUMMARY

More aggressive tumors are detected if low-risk prostate cancer patients are additionally monitored by magnetic resonance imaging. However, some high-grade tumors are detected only by transrectal ultrasound-guided biopsy.

Transrectal ultrasound-guided prostate biopsies vs. magnetic resonance imaging ultrasound fusion targeted biopsies: Who are the best candidates?

INTRODUCTION

The aim of this study was to compare the results of ultrasound-guided prostate biopsies (US-PB) and magnetic resonance imaging-ultrasound fusion biopsies (MRI-PB) in two contemporary cohorts and to describe the parameters orienting the choice of technique.

METHODS

Two contemporary cohorts of patients undergoing US-PB or MR-PB using the Urostation® (Koelis, Grenoble, France) between November 2010 and July 2015 were analyzed retrospectively. Patients with metastatic cancer or recurrence after treatment, saturation biopsies, and US-PB performed after a negative MRI were excluded. Comparison of populations, biopsy results, and clinical and biological parameters guiding the choice of technique were studied on multivariate analysis (logistic regression) taking into account the following confounding factors: age, prostate-specific antigen (PSA) rate, prostatic volume, number of previous biopsies, and abnormal digital rectal examination.

RESULTS

One hundred fourteen patients were included in the US-PB group and 118 in the MR-PB group. Prostate cancer was diagnosed among 65 patients in the US-PB group (detection rate 57.0%) and 70 patients in the MR-PB group (detection rate 59.3%) (odds ratio [OR] 3.00; 95% confidence interval [CI] 1.52-6.17; p=0.002). Among the cancers diagnosed in the MR-PB group, 21 were diagnosed by the two targeted biopsy cores only (15.5%). Patients undergoing MR-PB were significantly younger (p=0.0005), with a higher number of previous biopsy sessions (p<10-7) and larger prostate volume (p=0.001). PSA rate alone (p=0.23) and digital rectal examination (p=0.48) did not significantly interfere with the choice of a technique.

CONCLUSIONS

Younger patients with larger prostates and prior negative biopsy were more likely to be offered the MR-PB technique. On multivariate analysis, the detection rate was higher in the MR-PB group.

Multi-parametric magnetic resonance imaging monitoring patients in active surveillance for prostate cancer: a prospective cohort study

OBJECTIVES

To evaluate the use of multi-parametric magnetic resonance imaging (mpMRI) and mpMRI guided biopsies (MRGB) for monitoring an active surveillance (AS) prostate cancer cohort.

MATERIALS AND METHODS

One year after initial diagnostic TRUS guided biopsy (TRUS-bx), baseline mpMRI, and enrolment in an AS program patients underwent a one year follow-up comprising the usual TRUS-bx and an mpMRI. Prostate MRI lesions were scored on the five-point PIRADS scale version 2. In cases without TRUS-bx progression, patients with PIRADS 4 or 5 lesions were scheduled for MRGB. Progression in TRUS-bx was defined as Gleason score (Gs) up-grades, >3 tumor positive cores or a maximal cancer core length (MCCL) > 50%. In MRGB, Gs upgrade or a MCCL ≥6 mm Gs 3 + 3 lesions were considered to reflect progression. PSA increase or progression in clinical T-classification alone was not considered clinical progression.

RESULTS

50 patients were included in the study. In total 10 (20%) patients had per definition progression at one year follow-up. Seven patients (7/50 = 14%) had clinical progression based on TRUS-bx. mpMRI identified seven newly emerged PIRADS 4 lesions. Three patients with PIRADS 4 lesions had no sign of TRUS-bx progression, while MRGB revealed significant cancer (Gs 7 (3 + 4) and Gs 8 (3 + 5)). Consequently, seven patients underwent definitive treatment. Of these, six and four had a progression on MRI and TRUS-bx, respectively.

CONCLUSIONS

Our study suggests that mpMRI is at least equal to TRUS-bx in detecting progression at one year follow-up in prostate cancer patients undergoing active surveillance.

Prostate Cancer Imaging and Biomarkers Guiding Safe Selection of Active Surveillance

Background

Active surveillance (AS) is a widely adopted strategy to monitor men with low-risk, localized prostate cancer (PCa). Current AS inclusion criteria may misclassify as many as one in four patients. The advent of multiparametric magnetic resonance imaging (mpMRI) and novel PCa biomarkers may offer improved risk stratification. We performed a review of recently published literature to characterize emerging evidence in support of these novel modalities.

Methods

An English literature search was conducted on PubMed for available original investigations on localized PCa, AS, imaging, and biomarkers published within the past 3 years. Our Boolean criteria included the following terms: PCa, AS, imaging, biomarker, genetic, genomic, prospective, retrospective, and comparative. The bibliographies and diagnostic modalities of the identified studies were used to expand our search.

Results

Our review identified 222 original studies. Our expanded search yielded 244 studies. Among these, 70 met our inclusion criteria. Evidence suggests mpMRI offers improved detection of clinically significant PCa, and MRI-fusion technology enhances the sensitivity of surveillance biopsies. Multiple studies demonstrate the promise of commercially available screening assays for prediction of AS failure, and several novel biomarkers show promise in this setting.

Conclusion

In the era of AS for men with low-risk PCa, improved strategies for proper stratification are needed. mpMRI has dramatically enhanced the detection of clinically significant PCa. The advent of novel biomarkers for prediction of aggressive disease and AS failure has shown some initial promise, but further validation is warranted.

The Current State of MR Imaging-targeted Biopsy Techniques for Detection of Prostate Cancer

Systematic transrectal ultrasonography (US)-guided biopsy is the standard approach for histopathologic diagnosis of prostate cancer. However, this technique has multiple limitations because of its inability to accurately visualize and target prostate lesions. Multiparametric magnetic resonance (MR) imaging of the prostate is more reliably able to localize significant prostate cancer. Targeted prostate biopsy by using MR imaging may thus help to reduce false-negative results and improve risk assessment. Several commercial devices are now available for targeted prostate biopsy, including in-gantry MR imaging-targeted biopsy and real-time transrectal US-MR imaging fusion biopsy systems. This article reviews the current status of MR imaging-targeted biopsy platforms, including technical considerations, as well as advantages and challenges of each technique. ^© RSNA, 2017.

Delineation of Tumor Habitats based on Dynamic Contrast Enhanced MRI

Tumor heterogeneity can be elucidated by mapping subregions of the lesion with differential imaging characteristics, called habitats. Dynamic Contrast Enhanced (DCE-)MRI can depict the tumor microenvironments by identifying areas with variable perfusion and vascular permeability, since individual tumor habitats vary in the rate and magnitude of the contrast uptake and washout. Of particular interest is identifying areas of hypoxia, characterized by inadequate perfusion and hyper-permeable vasculature. An automatic procedure for delineation of tumor habitats from DCE-MRI was developed as a two-part process involving: (1) statistical testing in order to determine the number of the underlying habitats; and (2) an unsupervised pattern recognition technique to recover the temporal contrast patterns and locations of the associated habitats. The technique is examined on simulated data and DCE-MRI, obtained from prostate and brain pre-clinical cancer models, as well as clinical data from sarcoma and prostate cancer patients. The procedure successfully identified habitats previously associated with well-perfused, hypoxic and/or necrotic tumor compartments. Given the association of tumor hypoxia with more aggressive tumor phenotypes, the obtained in vivo information could impact management of cancer patients considerably.

Surface-enhanced Raman spectroscopy of serum accurately detects prostate cancer in patients with prostate-specific antigen levels of 4-10 ng/mL

The surface-enhanced Raman spectroscopy (SERS) of blood serum was investigated to differentiate between prostate cancer (PCa) and benign prostatic hyperplasia (BPH) in males with a prostate-specific antigen level of 4-10 ng/mL, so as to reduce unnecessary biopsies. A total of 240 SERS spectra from blood serum were acquired from 40 PCa subjects and 40 BPH subjects who had all received prostate biopsies and were given a pathological diagnosis. Multivariate statistical techniques, including principal component analysis (PCA) and linear discriminant analysis (LDA) diagnostic algorithms, were used to analyze the spectra data of serum from patients in control (CTR), PCa and BPH groups; results offered a sensitivity of 97.5%, a specificity of 100.0%, a precision of 100.0% and an accuracy of 99.2% for CTR; a sensitivity of 90.0%, a specificity of 97.5%, a precision of 94.7% and an accuracy of 98.3% for BPH; a sensitivity of 95.0%, a specificity of 93.8%, a precision of 88.4% and an accuracy of 94.2% for PCa. Similarly, this technique can significantly differentiate low- and high-risk PCa with an accuracy of 92.3%, a specificity of 95% and a sensitivity of 89.5%. The results suggest that analyzing blood serum using SERS combined with PCA-LDA diagnostic algorithms is a promising clinical tool for PCa diagnosis and assessment.

Multi-parametric magnetic resonance imaging as a management decision tool

The ability to image the prostate accurately and better characterize cancerous lesions makes multiparametric magnetic resonance imaging (mpMRI) an invaluable tool to improve management of localized prostate cancer (PCa). Improved risk stratification is warranted given the evidence of significant overtreatment of indolent PCa. mpMRI can more accurately rule out clinically significant PCa in men deciding between surveillance and definitive treatment to reduce overtreatment. mpMRI improves detection of clinically significant PCa, which helps minimize sampling error, a major limitation of the traditional diagnostic paradigm. Aside from helping determine candidacy for initial surveillance vs. treatment, mpMRI is a useful tool for following men on active surveillance (AS) with the potential to reduce the need for serial biopsies. When definitive treatment is warranted, mpMRI can be used to determine the local extent of disease. This provides information that is useful in the treatment decision, counseling about outcomes, and surgical planning. While mpMRI is a significant step forward in PCa management, it is necessary to understand its limitations. mpMRI and MRI-guided fusion biopsy techniques still do not detect all clinically significant tumors. The utility of current mpMRI techniques is limited by the multifocal nature of PCa with poor detection of non-index lesions, inaccurate estimation of tumor size and geometry, and the need for interpretation by specialized radiologists. The role of mpMRI will continue to expand as improvements in technology and experience help overcome these limitations.

The Emerging Role of MRI in Prostate Cancer Active Surveillance and Ongoing Challenges

OBJECTIVE

Active surveillance (AS) has emerged as a management strategy for preventing overtreatment of indolent prostate cancer. Selection of patients for AS has traditionally proved challenging and resulted in 20-30% misclassification rates. MRI has potential to help overcome this limitation, broaden selection criteria to increase recruitment, and minimize the invasive nature of AS follow-up.

CONCLUSION

The main issues surrounding MRI and AS are the heterogeneity of inclusion criteria, the definition of significant disease, and agreement about what constitutes radiologic progression. Prospective cohorts with MRI at enrollment and long-term follow-up are required to further address these issues.

Comparison of image quality and patient discomfort in prostate MRI: pelvic phased array coil vs. endorectal coil

PURPOSE

To compare image quality (IQ) and patient discomfort during prostate MRI using a pelvic phased array (PPA) coil and an endorectal (ER) coil.

MATERIALS AND METHODS

Ninety-eight patients (median age, 65.7; range 42.1-78.1) underwent prostate MRI on a 3T scanner including T2w and DWI acquired with PPA and an ER coil within the same exam. Acquisition time was kept similar for both acquisitions. Two radiologists evaluated aspects of IQ on a 5-point Likert scale and classified image artifacts. All patients completed a questionnaire on discomfort/pain regarding the ER coil using a visual analogue scale from 1 to 10.

RESULTS

There was no significant difference in overall IQ for T2w images for both readers (reader 1, 3.27 ± 0.91 and 3.07 ± 0.84, p = 0.057; reader 2, 3.70 ± 0.75 and 3.77 ± 0.81, p = 0.555) for PPA and ER coils, respectively. Overall IQ for DWI acquired with PPA and ER coils was rated similar by reader 1 (3.03 ± 1.10 and 3.08 ± 0.80, respectively, (p = 0.67)), while reader 2 preferred ER coil images (3.27 ± 0.81 and 3.66 ± 0.85 (p < 0.05)). Susceptibility artifacts were more frequent in ER than in PPA coil images (109 vs. 75). Discomfort and pain experienced during insertion of the ER coil was low altogether (VAS score, 3.5 ± 2.1 for "discomfort" and 2.4 ± 2.4 for "pain").

CONCLUSION

T2-weighted images may be acquired with comparable IQ using a PPA coil as compared to an ER coil, while DWI images showed better IQ using the ER coil for one of two readers. The insertion of the ER coil caused low to moderate discomfort and pain in patients.

Integration of multiparametric MRI into active surveillance of prostate cancer

Prostate cancer is the most common noncutaneous cancer in men though many men will not die of this disease and may not require definitive treatment. Active surveillance (AS) is an increasingly utilized potential solution to the issue of overtreatment of prostate cancer. Traditionally, prostate cancer patients have been stratified into risk groups based on clinical stage on digital rectal examination, prostate-specific antigen and biopsy Gleason score, though each of these variables has significant limitations. This review will discuss the potential role for prostate multiparametric MRI and targeted biopsy techniques incorporating MRI in the selection of candidates for AS, monitoring patients on AS and as triggers for definitive treatment.

Proposed Adjustments to PI-RADS Version 2 Decision Rules: Impact on Prostate Cancer Detection

Purpose To test the impact of existing Prostate Imaging Reporting and Data System (PI-RADS) version 2 (V2) decision rules, as well as of proposed adjustments to these decision rules, on detection of Gleason score (GS) 7 or greater (GS ≥7) prostate cancer. Materials and Methods Two radiologists independently provided PI-RADS V2 scores for the dominant lesion on 343 prostate magnetic resonance (MR) examinations. Diagnostic performance for GS ≥7 tumor was assessed by using MR imaging-ultrasonography fusion-targeted biopsy as the reference. The impact of existing PI-RADS V2 decision rules, as well as a series of exploratory proposed adjustments, on the frequency of GS ≥7 tumor detection, was evaluated. Results A total of 210 lesions were benign, 43 were GS 6, and 90 were GS ≥7. Lesions were GS ≥7 in 0%-4.1% of PI-RADS categories 1 and 2, 11.4%-27.1% of PI-RADS category 3, 44.4%-49.3% of PI-RADS category 4, and 72.1%-73.7% of PI-RADS category 5 lesions. PI-RADS category 4 or greater had sensitivity of 78.9%-87.8% and specificity of 75.5%-79.1 for detecting GS ≥7 tumor. The frequency of GS ≥7 tumor for existing PI-RADS V2 decision rules was 30.0%-33.3% in peripheral zone (PZ) lesions upgraded from category 3 to 4 based on dynamic contrast enhancement (DCE) score of positive; 50.0%-66.7% in transition zone (TZ) lesions upgraded from category 3 to 4 based on diffusion-weighted imaging (DWI) score of 5; and 71.7%-72.7% of lesions in both zones upgraded from category 4 to 5 based on size of 15 mm or greater. The frequency of GS ≥7 tumor for proposed adjustments to the decision rules was 30.0%-60.0% for TZ lesions upgraded from category 3 to 4 based on DWI score of 4; 33.3%-57.1% for TZ lesions upgraded from category 3 to 4 based on DCE score of positive when incorporating new criteria (unencapsulated sheetlike enhancement) for DCE score of positive in TZ; and 56.4%-61.9% for lesions in both zones upgraded from category 4 to 5 based on size of 10-14 mm. Other proposed adjustments yielded GS ≥7 tumor in less than 15% of cases for one or more readers. Conclusion Existing PI-RADS V2 decision rules exhibited reasonable performance in detecting GS ≥7 tumor. Several proposed adjustments to the criteria (in TZ, upgrading category 3 to 4 based on DWI score of 4 or modified DCE score of positive; in PZ or TZ, upgrading category 4 to 5 based on size of 10-14 mm) may also have value for this purpose. ^© RSNA, 2016 Online supplemental material is available for this article.

Prostate magnetic resonance imaging findings in patients treated for testosterone deficiency while on active surveillance for low-risk prostate cancer

OBJECTIVE

To investigate the multiparametric prostate magnetic resonance imaging (mpMRI) findings in patients treated with testosterone replacement therapy (TRT) while on active surveillance for low-risk prostate cancer.

METHODS

We retrospectively reviewed 12 patients who underwent mpMRI before and after TRT while on active surveillance. Changes in serum testosterone level, prostate-specific antigen (PSA), prostate biopsy findings, prostate volume, and Prostate Imaging Reporting and Data System Version 2 (PI-RADSv2) score before and after TRT were summarized.

RESULTS

After TRT, there was a significant increase in serum testosterone (516.5ng/dl vs. 203.0ng/dl), PSA (4.2ng/ml vs. 3.3ng/ml), and prostate volume (55.2cm³ vs. 39.4cm³). In total, 2 patients had biopsy progression during the study period. The PI-RADSv2 scores before and after TRT were unchanged in 10/12 patients; none of these demonstrated biopsy progression on post-TRT. The PI-RADSv2 scores increased after TRT in 2/12 patients; both showed Gleason score upgrade on follow-up biopsy. Of these 2 patients, 1 patient underwent radical treatment due to clinical progression. The area under the curve for detecting biopsy progression calculated from PI-RADSv2 score after TRT was 0.90, which was better than that calculated from post-TRT PSA level (0.48).

CONCLUSIONS

After TRT, mpMRI findings remained stable in patients without biopsy progression, whereas PI-RADSv2 score increase was identified in patients with Gleason score upgrade on follow-up biopsy.

Primary Gleason pattern upgrading in contemporary patients with D'Amico low-risk prostate cancer: implications for future biomarkers and imaging modalities

OBJECTIVE

To retrospectively assess the rate of high-grade primary Gleason upgrading (HGPGU) to primary Gleason pattern 4 or 5 in a contemporary cohort of patients with D'Amico low-risk prostate cancer including those who fulfilled Prostate Cancer Research International Active Surveillance (PRIAS) criteria, and to develop a tool for HGPGU prediction. HGPGU is a contraindication in most active surveillance (AS) and focal therapy protocols.

PATIENTS AND METHODS

In all, 10 616 patients with localised prostate cancer were treated at a high-volume European tertiary care centre from 2010 to 2015 with radical prostatectomy. Analyses were restricted to 1 819 patients with D'Amico low-risk prostate cancer (17.1%) with prostate-specific antigen (PSA) levels of <10.0 ng/mL, cT1c-cT2a and Gleason score ≤6, and were repeated within 772 of the men (7.3%) who fulfilled the PRIAS criteria for AS (PSA level of ≤10 ng/mL, T1c-T2, Gleason score ≤6, PSA density (PSAD) of <0.2 ng/mL² , ≤2 positive cores). Uni- and multivariable logistic regression models were fitted, testing predictors of HGPGU. The final logistic regression model was based on the most informative variables.

RESULTS

There was HGPGU in 88 (4.8%) patients with D'Amico low-risk prostate cancer and in 32 (4.1%) of the subgroup who were PRIAS eligible. Multivariable analysis predicting HGPGU for the patients with D'Amico low-risk yielded three independent predictors: age, PSAD, and clinical tumour stage (P = 0.008, P = 0.005 and P = 0.021, respectively). Within the same patients, the model using all vs the most informative variables resulted in area under the curves (AUCs) of 69.2% and 68.3%, respectively. Multivariable analysis of those who were PRIAS eligible, yielded age and number of positive cores as independent predictors of HGPGU (P = 0.002 and P = 0.049, respectively; AUC 64.9%).

CONCLUSIONS

The low accuracy (invariably <70%) for HGPGU prediction in both patients with D'Amico low-risk prostate cancer and PRIAS eligibility indicates that these variables have poor predictive ability in contemporary patients. Despite HGPGU being a rare phenomenon, it may have life threatening implications and consequently alternatives such as biomarkers, genetic markers, or imaging modalities at re-biopsy are needed.

Transperineal Versus Transrectal MRI/TRUS Fusion Targeted Biopsy: Detection Rate of Clinically Significant Prostate Cancer

INTRODUCTION

To evaluate the detection rate for clinically significant prostate cancer (PCa) of transperineal (TP) versus transrectal (TR) multiparametric (mp) magnetic resonance imaging (MRI)/transrectal ultrasound-guided (TRUS) fusion targeted biopsy.

PATIENTS AND METHODS

From January 2015 to January 2016, a total of 200 men (median age, 61 years) with negative digital rectal examination findings underwent repeat saturation TP prostate biopsy (SPBx; median 30 cores) for increasing or persistent elevated prostate-specific antigen values. Ten day before SPBx, all patients underwent 3.0 T pelvic mpMRI (Achieva 3T; Philips Healthcare Best, Netherlands). In the presence of mpMRI lesions suggestive of cancer (Prostate Imaging-Reporting and Data System [PI-RADS] score 4/5), targeted mpMRI/TRUS TR fusion guided biopsies (4 cores) and TP cognitive biopsies (4 cores) were added to SPBx.

RESULTS

Median prostate-specific antigen was 8.6 ng/mL, and mpMRI revealed a suspicious lesion in 95 (47.5%) of 200 cases. Overall, in 60 (30%) of 200 men, a clinically significant PCa was found, and in all cases, mpMRI was positive. SPBx, TR fusion, and mpMRI/TRUS TP cognitive targeted biopsy diagnosed 59 (98.3%), 40 (78.3%), and 56 (93.3%) clinically significant PCa, respectively. TR fusion versus TP targeted biopsy missed 12 versus 1 (P = .001) cancers of the anterior zone and 8 versus 3 (P = .12) cancers of the peripheric gland, respectively; moreover, PCa diagnosed by TR fusion versus TP targeted biopsy had a mpMRI lesion diameter and percentage of positive cores equal to 13 versus 10 mm and 33% versus 58% (P = .001), respectively.

CONCLUSION

mpMRI/TRUS TP cognitive targeted biopsy found a greater percentage of clinically significant PCa of the anterior zone compared to the mpMRI/TRUS TR fusion approach (93.3% vs. 25%; P = .0001).

A Decade of Active Surveillance in the PRIAS Study: An Update and Evaluation of the Criteria Used to Recommend a Switch to Active Treatment

BACKGROUND

The Prostate Cancer Research International Active Surveillance (PRIAS) study was initiated a decade ago to study the most optimal selection and follow-up of men on active surveillance (AS).

OBJECTIVE

We report on 10 yr of follow-up of men on AS in the PRIAS study and evaluate if criteria used to recommend a switch to active treatment truly predict unfavorable outcome on subsequent radical prostatectomy (RP).

DESIGN, SETTING, AND PARTICIPANTS

Men with low-risk prostate cancer were included and followed prospectively on AS. Follow-up consisted of regular prostate-specific antigen (PSA) tests, digital rectal examinations, and biopsies. Men with Gleason >3+3, more than two positive biopsy cores, or stage higher than cT2 were advised to switch to active treatment (until 2014, a PSA doubling time [PSA DT] of 0-3 yr was also used).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Reclassification rates, treatment after discontinuation, and outcome on RP after discontinuing AS were reported. Regression analysis on the outcome of RP was used to evaluate the predictive value of criteria currently used to recommend a switch to active treatment. Kaplan-Meier and competing risk analysis were used to report discontinuation rates over time and long-term oncologic end points.

RESULTS AND LIMITATIONS

A total of 5302 men were included in PRIAS across 18 countries. Reclassification rates remained stable on all subsequent biopsies, with 22-33% of men having either Gleason >3+3 or more than two positive cores on any repeat biopsy. At 5 and 10 yr of follow-up, 52% and 73% of men, respectively, had discontinued AS, most of them because of protocol-based reclassification. A third of men undergoing subsequent RP had favorable pathologic tumor features (Gleason 3+3 and pT2). Of the criteria used to recommend a switch to active treatment, more than two positive cores and a PSA DT of 0-3 yr were not predictive of unfavorable pathologic outcome on RP.

CONCLUSIONS

A substantial group of men discontinued AS without subsequent unfavorable tumor features on RP; therefore, we propose Gleason upgrading and cT3 as the only indicators for an immediate switch to active treatment. Surrogate indicators (eg, more than two positive cores and a fast-rising PSA) should not trigger immediate active treatment but rather further investigation to confirm the suspicion of higher risk disease.

PATIENT SUMMARY

We confirmed the safety of active surveillance as a treatment option for men with low-risk prostate cancer; however, some changes could be made to the follow-up protocol to safely increase the number of men who remain on active surveillance.

Use of a Quality Improvement Initiative to Achieve Consistent Reporting of Level of Suspicion for Tumor on Multiparametric Prostate MRI

OBJECTIVE

The purpose of this article is to evaluate the utility of a quality improvement (QI) initiative in achieving long-term adherence to an evolving structured format for reporting the level of suspicion for tumor on prostate MRI examinations.

MATERIALS AND METHODS

The original QI initiative occurred over a 4-month period in 2010, before which prostate MRI was reported using free text. The initiative consisted of development of a section-wide macro, an initial group training session, ordering physician input regarding the structured report's value, subsequent weekly sessions for ongoing review, and timely individualized feedback in instances of nonuse. The initial structured report included pick lists for describing the level of suspicion for tumor as negative, low, medium, or high. Pick lists were modified in 2011 to incorporate a 5-point Likert scale and again in 2015 to incorporate Prostate Imaging Data and Reporting System (PI-RADS) version 2. These refinements were implemented after accelerated training periods. The frequency of reports providing an MRI-based suspicion level during these periods was assessed.

RESULTS

Fifty-five percent of reports provided an MRI-based level of suspicion for tumor before the initiative. For various cohorts evaluated after the initiative (using structured reports based on the low, medium, or high scheme; a numeric Likert scale; or PI-RADS), this frequency improved to 95-100% (p < 0.001). Among reports without a suspicion level, potential confounding factors included marked artifact from hip prosthesis and overt diffuse tumor.

CONCLUSION

The QI initiative achieved excellent adherence in reporting a suspicion level for tumor on prostate MRI examinations. The described components of the initiative were useful for maintaining long-term adherence that persisted after serial modifications to the report lexicon.

Serial transperineal sector prostate biopsies: impact on long-term erectile dysfunction

We wanted to determine whether serial transperineal sector prostate biopsies have a long-term effect on erectile dysfunction (ED). A total of 64 men with prostate cancer entered our active surveillance (AS) programme after a transrectal prostate biopsy as well as a confirmatory initial transperineal sector prostate biopsy (TPSBx). A repeat TPSBx was performed 24 months later as part of our active surveillance protocol. The International Index of Erectile Function-5 (IIEF-5) questionnaire assessed ED at baseline prior to each TPSBx, and at one, three, and six months after first and second TPSBx.

There was a significant short-term deterioration in erectile function on mean IIEF-5 score between baseline (19.5), when compared to one month (10.5) (P <0.001) and three months (18.7) (P = 0.001) following first TPSBx. This resolved at six month follow-up (19.6) (P = 0.681). Following second TPSBx, there was a deterioration in erectile function between baseline (16.6), compared to one month (7.3), three months (13.8), and six months (15.9) (P <0.05) following second TPSBx. Initial TPSBx caused significant short-term ED, which resolved by six months. Serial TPSBx appears to have an adverse impact on erectile function in men monitored on AS, increasing the risk of long-term ED. This risk should be highlighted and discussed during the consent process.

In-bore magnetic resonance-guided transrectal biopsy for the detection of clinically significant prostate cancer

PURPOSE

To determine the safety and efficacy of in-bore magnetic resonance-guided prostate biopsy (MRGB) for detection of clinically significant disease (CSD) in untreated men with known or suspected prostate cancer (PCa).

METHODS

512 patients underwent multiparametric magnetic resonance imaging (Mp-MRI) followed by MRGB at one of three centers in this IRB-approved, HIPAA-compliant, retrospective study. Exclusion criteria were prior prostate cancer therapy and incomplete Mp-MRI (n = 51). Patients (n = 461) were analyzed in two subcohorts: no prior PCa (NP) (n = 381) and active surveillance (AS) (n = 80). Detection rates of PCa and CSD (Gleason Score ≥3 + 4) were calculated and compared among subcohorts and by Mp-MRI assessment grade. Logistic regression was performed to identify predictors for detection of PCa and CSD.

RESULTS

Mean patient age was 66 years, median prostate-specific antigen (PSA) was 7.5 ng/mL, and median prostate volume was 54 cc. A mean of 1.7 targets was sampled per gland. Significant adverse events (urosepsis and hematuria with obstruction) occurred in 1% (5/461). Overall PCa detection rates were 51% per patient (233/461) and 37% per lesion (282/757). 65% (151/233) of men with detected PCa had CSD. Per-patient PCa detection rates in the NP and AS subcohorts were 47% (178/381) and 69% (55/80), respectively, significantly higher in the AS group (p < 0.001). CSD was detected in 10% (47/451), 43% (96/225) and 84% (68/81) of lesions with Mp-MRI assessment grades of 3, 4, and 5, respectively. Older age, higher PSA, and lower prostate volume predicted MRGB detection of CSD (OR 1.07 and p = 0.003, OR 1.1 and p = 0.014, and OR 0.98 and p = 0.032, respectively).

CONCLUSIONS

In-bore MRGB is safe and high yield for detection of CSD.

Interobserver Reproducibility of the PI-RADS Version 2 Lexicon: A Multicenter Study of Six Experienced Prostate Radiologists

Purpose To determine the interobserver reproducibility of the Prostate Imaging Reporting and Data System (PI-RADS) version 2 lexicon. Materials and Methods This retrospective HIPAA-compliant study was institutional review board-approved. Six radiologists from six separate institutions, all experienced in prostate magnetic resonance (MR) imaging, assessed prostate MR imaging examinations performed at a single center by using the PI-RADS lexicon. Readers were provided screen captures that denoted the location of one specific lesion per case. Analysis entailed two sessions (40 and 80 examinations per session) and an intersession training period for individualized feedback and group discussion. Percent agreement (fraction of pairwise reader combinations with concordant readings) was compared between sessions. κ coefficients were computed. Results No substantial difference in interobserver agreement was observed between sessions, and the sessions were subsequently pooled. Agreement for PI-RADS score of 4 or greater was 0.593 in peripheral zone (PZ) and 0.509 in transition zone (TZ). In PZ, reproducibility was moderate to substantial for features related to diffusion-weighted imaging (κ = 0.535-0.619); fair to moderate for features related to dynamic contrast material-enhanced (DCE) imaging (κ = 0.266-0.439); and fair for definite extraprostatic extension on T2-weighted images (κ = 0.289). In TZ, reproducibility for features related to lesion texture and margins on T2-weighted images ranged from 0.136 (moderately hypointense) to 0.529 (encapsulation). Among 63 lesions that underwent targeted biopsy, classification as PI-RADS score of 4 or greater by a majority of readers yielded tumor with a Gleason score of 3+4 or greater in 45.9% (17 of 37), without missing any tumor with a Gleason score of 3+4 or greater. Conclusion Experienced radiologists achieved moderate reproducibility for PI-RADS version 2, and neither required nor benefitted from a training session. Agreement tended to be better in PZ than TZ, although was weak for DCE in PZ. The findings may help guide future PI-RADS lexicon updates. (©) RSNA, 2016 Online supplemental material is available for this article.

Active surveillance for prostate cancer

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