Role of Changes in Magnetic Resonance Imaging or Clinical Stage in Evaluation of Disease Progression for Men with Prostate Cancer on Active Surveillance

Evaluating 4Kscore's role in predicting progression on active surveillance for prostate cancer independently of clinical information and PIRADS score

BACKGROUND

4Kscore is used to aid the decision for prostate biopsy, however its role in active surveillance (AS) has not been investigated in a magnetic resonance imaging (MRI)-based protocol. Our objective was to assess the association between 4Kscore and progression in men undergoing AS on a prospective MRI-based protocol.

METHODS

This was a single-institution, single-arm, non-therapeutic, interventional trial of 166 men with biopsy-confirmed prostate cancer enrolled between 2014-2020. Patients were placed on a trial-mandated AS protocol including yearly multiparametric (mp)MRI, prostate biopsy, and 4Kscore followed for 48 months after diagnosis. We analyzed protocol-defined and grade progression at confirmatory and subsequent surveillance biopsies.

RESULTS

Out of 166 patients, 83 (50%) men progressed per protocol and of them 41 (24.7% of whole cohort) progressed by grade. At confirmatory biopsy, men with a baseline 4Kscore ≥ 20% had a higher risk of grade progression compared to those with 4Kscore < 20% (OR = 4.04, 95% CI: 1.05-15.59, p = 0.043) after adjusting for National Comprehensive Cancer Network (NCCN) risk and baseline PIRADS score. At surveillance biopsies, most recent 4Kscore ≥ 20% significantly predicted per protocol (OR = 2.61, 95% CI: 1.03-6.63, p = 0.044) and grade progression (OR = 5.13, 95% CI: 1.63-16.11, p = 0.005).

CONCLUSIONS

For patients on AS, baseline 4Kscore predicted grade progression at confirmatory biopsy, and most recent 4Kscore predicted per-protocol and grade progression at surveillance biopsy.

MRI and active surveillance: thoughts from across the pond

In the United States (US), urological guidelines recommend active surveillance (AS) for patients with low-risk prostate cancer (PCa) and endorse it as an option for those with favorable intermediate-risk PCa with a > 10-year life expectancy. Multiparametric magnetic resonance imaging (mpMRI) is being increasingly used in the screening, monitoring, and staging of PCa and involves the combination of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced T1-weighted imaging. The American Urological Association (AUA) guidelines provide recommendations about the use of mpMRI in the confirmatory setting for AS patients but do not discuss the timing of follow-up mpMRI in AS. The National Comprehensive Cancer Network (NCCN) discourages using it more frequently than every 12 months. Finally, guidelines state that mpMRI can be used to augment risk stratification but should not replace periodic surveillance biopsy. In this review, we discuss the current literature regarding the use of mpMRI for patients with AS, with a particular focus on the approach in the US. Although AS shows a benefit to the addition of mpMRI to diagnostic, confirmatory, and follow-up biopsy, there is no strong evidence to suggest that mpMRI can safely replace biopsy for most patients and thus it must be incorporated into a multimodal approach. CLINICAL RELEVANCE STATEMENT: According to the US guidelines, regular follow-ups are important for men with prostate cancer on active surveillance, and prostate MRI is a valuable tool that should be utilized, in combination with PSA kinetics and biopsies, for monitoring prostate cancer. KEY POINTS: According to the US guidelines, the addition of MRI improves the detection of clinically significant prostate cancer. Timing interval imaging of patients on active surveillance remains unclear and has not been specifically addressed. MRI should trigger further work-ups, but not replace periodic follow-up biopsies, in men on active surveillance.

Oncological Outcomes in Men With Favorable Intermediate Risk Prostate Cancer Enrolled in Active Surveillance

BACKGROUND/AIM

To evaluate the long-term oncological outcomes in men with intermediate risk prostate cancer (PCa) enrolled in active surveillance (AS).

PATIENTS AND METHODS

From April 2015 to December 2022, 30 men with Gleason score 3+4/ISUP Grade Group2 (GG2), greatest percentage of cancer (GPC) ≤50%, Gleason pattern 4 ≤10%, ≤3 positive biopsy cores were enrolled in AS. All patients underwent confirmatory transperineal saturation biopsy (SPBx: 20 cores) 12 months from diagnosis plus multiparametric magnetic resonance (mpMRI) evaluation. At the last follow-up, 68Ga prostate-specific membrane antigen (PSMA) positron-emission tomography (PET)/computed tomography (CT) was added: lesions with PIRADS score ≥3 and/or standardized uptake value (SUVmax) >5 were submitted to four targeted cores.

RESULTS

Three out of 30 (10%) men with GG2 PCa were reclassified at confirmatory biopsy. At the last follow-up (median 5.2 years), only 2 of 27 (7.4%) men were reclassified and 23/30 (76.6%) continued AS.

CONCLUSION

Men with favorable GG2 PCa enrolled in AS have good long-term oncological results. The use of selective criteria (i.e., SPBx, mpMRI, PSMA PET/CT) reduces the risk of reclassification.

Cancer Detection Rate and Abnormal Interpretation Rate of Prostate MRI in Patients With Low-Grade Cancer

PURPOSE

The aim of this study was to evaluate the utility of cancer detection rate (CDR) and abnormal interpretation rate (AIR) in prostate MRI for patients with low-grade prostate cancer (PCa).

METHODS

This three-center retrospective study included patients who underwent prostate MRI from 2017 to 2021 with known low-grade PCa (Gleason score 6) without prior treatment. Patient-level highest Prostate Imaging Reporting & Data System (PI-RADS®) score and pathologic diagnosis within 1 year after MRI were used to evaluate the diagnostic performance of prostate MRI in detecting clinically significant PCa (csPCa; Gleason score ≥ 7). The metrics AIR, CDR, and CDR adjusted for pathologic confirmation rate were calculated. Radiologist-level AIR-CDR plots were shown. Simulation AIR-CDR lines were created to assess the effects of different diagnostic performances of prostate MRI and the prevalence of csPCa.

RESULTS

A total of 3,207 examinations were interpreted by 33 radiologists. Overall AIR, CDR, and CDR adjusted for pathologic confirmation rate at PI-RADS 3 to 5 (PI-RADS 4 and 5) were 51.7% (36.5%), 22.1% (18.8%), and 30.7% (24.6%), respectively. Radiologist-level AIR and CDR at PI-RADS 3 to 5 (PI-RADS 4 and 5) were in the 36.8% to 75.6% (21.9%-57.5%) range and the 16.3%-28.7% (10.9%-26.5%) range, respectively. In the simulation, changing parameters of diagnostic performance or csPCa prevalence shifted the AIR-CDR line.

CONCLUSIONS

The authors propose CDR and AIR as performance metrics in prostate MRI and report reference performance values in patients with known low-grade PCa. There was variability in radiologist-level AIR and CDR. Combined use of AIR and CDR could provide meaningful feedback for radiologists to improve their performance by showing relative performance to other radiologists.

PIRADS≥4 MRI lesion: Is performing systematic biopsies still essential for detecting clinically significant prostate cancer?

INTRODUCTION

In the era of targeted prostate biopsies, the necessity of performing randomized biopsies systematically is under question. Our objective is to evaluate the rate of clinically significant prostate cancer (csPCa), defined by presence of ISUP≥2 prostate cancer, diagnosed only on randomized cores in case of a PIRADS≥4 target lesion on MRI. The secondary objective is to evaluate whether specific variables can predict the presence of undetected csPCa in targeted biopsies.

METHODS

Retrospective data on targeted biopsies performed from 2015 to 2021 in our hospital were collected. Procedures were performed with MRI/Transrectal US fusion Trinity platform from Koelis®. All the MRI images were reviewed and the targets were classified using the PIRADS V2.1 classification. Inclusion criteria comprised procedures featuring at least one PIRADS≥4 targeted lesion were included. All procedures consisted 1-4 targeted cores and 12-core systematic biopsy.

RESULTS

We included 358 patients. In 44 patients (12.3%) csPCa was exclusively detected in randomized cores. Among these cases, only 12 patients (27.2%) showed no cancer on the targeted biopsies. Merely 4 patients (9.09%) lacked csPCa-positive cores on the same side as the index lesion. Factors such as PSA, PSA density, prostate volume, and digital rectal examination showed no significant association with the presence of csPCa exclusively on randomized cores. Likewise, the size, location, and PIRADS classification of the target demonstrated no significant impact.

CONCLUSION

Our findings indicate that in 12.3% of cases, targeted biopsies alone are insufficient for detecting the presence of csPCa. As such, systematic biopsies remain necessary to date.

LEVEL OF EVIDENCE: 4

Prospective comparison of restriction spectrum imaging and non-invasive biomarkers to predict upgrading on active surveillance prostate biopsy

BACKGROUND

Protocol-based active surveillance (AS) biopsies have led to poor compliance. To move to risk-based protocols, more accurate imaging biomarkers are needed to predict upgrading on AS prostate biopsy. We compared restriction spectrum imaging (RSI-MRI) generated signal maps as a biomarker to other available non-invasive biomarkers to predict upgrading or reclassification on an AS biopsy.

METHODS

We prospectively enrolled men on prostate cancer AS undergoing repeat biopsy from January 2016 to June 2019 to obtain an MRI and biomarkers to predict upgrading. Subjects underwent a prostate multiparametric MRI and a short duration, diffusion-weighted enhanced MRI called RSI to generate a restricted signal map along with evaluation of 30 biomarkers (14 clinico-epidemiologic features, 9 molecular biomarkers, and 7 radiologic-associated features). Our primary outcome was upgrading or reclassification on subsequent AS prostate biopsy. Statistical analysis included operating characteristic improvement using AUROC and AUPRC.

RESULTS

The individual biomarker with the highest area under the receiver operator characteristic curve (AUC) was RSI-MRI (AUC = 0.84; 95% CI: 0.71-0.96). The best non-imaging biomarker was prostate volume-corrected Prostate Health Index density (PHI, AUC = 0.68; 95% CI: 0.53-0.82). Non-imaging biomarkers had a negligible effect on predicting upgrading at the next biopsy but did improve predictions of overall time to progression in AS.

CONCLUSIONS

RSI-MRI, PIRADS, and PHI could improve the predictive ability to detect upgrading in AS. The strongest predictor of clinically significant prostate cancer on AS biopsy was RSI-MRI signal output.

Application of Advanced Imaging to Prostate Cancer Diagnosis and Management: A Narrative Review of Current Practice and Unanswered Questions

Major advances in prostate cancer diagnosis, staging, and management have occurred over the past decade, largely due to our improved understanding of the technical aspects and clinical applications of advanced imaging, specifically magnetic resonance imaging (MRI) and prostate-cancer-specific positron emission tomography (PET). Herein, we review the established utility of these important and exciting technologies, as well as areas of controversy and uncertainty that remain important areas for future study. There is strong evidence supporting the utility of MRI in guiding initial biopsy and assessing local disease. There is debate, however, regarding how to best use the imaging modality in risk stratification, treatment planning, and assessment of biochemical failure. Prostate-cancer-specific PET is a relatively new technology that provides great value to the evaluation of newly diagnosed, treated, and recurrent prostate cancer. However, its ideal use in treatment decision making, staging, recurrence detection, and surveillance necessitates further research. Continued study of both imaging modalities will allow for an improved understanding of their best utilization in improving cancer care.

68Ga-PSMA-PET/CT in addition to mpMRI in men undergoing biopsy during active surveillance for low- to intermediate-risk prostate cancer: study protocol for a prospective cross-sectional study

Background

In active surveillance there is significant interest in whether imaging modalities such as multiparametric magnetic resonance imaging (mpMRI) or 68Gallium prostate-specific membrane antigen positron emission tomography/computerized tomography (68Ga-PSMA-PET/CT) can improve the detection of progression to clinically significant prostate cancer (csPCa) and thus reduce the frequency of prostate biopsies and associated morbidity. Recent studies have demonstrated the value of mpMRI in active surveillance; however, mpMRI does miss a proportion of disease progression and thus alone cannot replace biopsy. To date, prostate-specific membrane antigen positron emission tomography (PSMA-PET) has shown additive value to mpMRI in its ability to detect prostate cancer (PCa) in the primary diagnostic setting. Our objective is to evaluate the diagnostic utility of PSMA-PET to detect progression to csPCa in active surveillance patients.

Methods

We will perform a prospective, cross-sectional, partially blinded, multicentre clinical trial evaluating the additive value of PSMA-PET with mpMRI against saturation transperineal template prostate biopsy. Two hundred and twenty-five men will be recruited who have newly diagnosed PCa which is suitable for active surveillance. Following enrolment, patients will undergo a PSMA-PET and mpMRI within 3 months of a repeat 12-month confirmatory biopsy. Patients who remain on active surveillance after confirmatory biopsy will then be planned to have a further mpMRI and PSMA-PET prior to a repeat biopsy in 3-4 years. The primary outcome is to assess the ability of PSMA-PET to detect or exclude significant malignancy on repeat biopsy. Secondary outcomes include (I) assess the comparative diagnostic accuracies of mpMRI and PSMA-PET alone [sensitivity/specificity/negative predictive value (NPV)/positive predictive value (PPV)] to detect progression on biopsy based on predefined histologic criteria for progression; (II) comparison of index lesion identification by template biopsies vs. MRI targeted lesions vs. PSMA targeted lesions; (III) evaluation of concordance of lesions identified on final histopathology and each imaging modality (PSMA-PET and/or mpMRI) in the subset of patients proceeding to RP.

Discussion

The results of this trial will define the role of PSMA-PET in active surveillance and potentially reduce the number of biopsies needed to detect progression to csPCa.

Trial Registration

The current trial was registered with the ANZCTR on the 3/2/2022 with the trial ID ACTRN12622000188730, it is accessible at https://www.anzctr.org.au/.

Retrospective T2 quantification from conventional weighted MRI of the prostate based on deep learning

Purpose

To develop a deep learning-based method to retrospectively quantify T2 from conventional T1- and T2-weighted images.

Methods

Twenty-five subjects were imaged using a multi-echo spin-echo sequence to estimate reference prostate T2 maps. Conventional T1- and T2-weighted images were acquired as the input images. A U-Net based neural network was developed to directly estimate T2 maps from the weighted images using a four-fold cross-validation training strategy. The structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), mean percentage error (MPE), and Pearson correlation coefficient were calculated to evaluate the quality of network-estimated T2 maps. To explore the potential of this approach in clinical practice, a retrospective T2 quantification was performed on a high-risk prostate cancer cohort (Group 1) and a low-risk active surveillance cohort (Group 2). Tumor and non-tumor T2 values were evaluated by an experienced radiologist based on region of interest (ROI) analysis.

Results

The T2 maps generated by the trained network were consistent with the corresponding reference. Prostate tissue structures and contrast were well preserved, with a PSNR of 26.41 ± 1.17 dB, an SSIM of 0.85 ± 0.02, and a Pearson correlation coefficient of 0.86. Quantitative ROI analyses performed on 38 prostate cancer patients revealed estimated T2 values of 80.4 ± 14.4 ms and 106.8 ± 16.3 ms for tumor and non-tumor regions, respectively. ROI measurements showed a significant difference between tumor and non-tumor regions of the estimated T2 maps (P < 0.001). In the two-timepoints active surveillance cohort, patients defined as progressors exhibited lower estimated T2 values of the tumor ROIs at the second time point compared to the first time point. Additionally, the T2 difference between two time points for progressors was significantly greater than that for non-progressors (P = 0.010).

Conclusion

A deep learning method was developed to estimate prostate T2 maps retrospectively from clinically acquired T1- and T2-weighted images, which has the potential to improve prostate cancer diagnosis and characterization without requiring extra scans.

Aggressive Prostate Cancer in Patients Treated with Active Surveillance

Active surveillance has emerged as a promising approach for managing low-risk and favorable intermediate-risk prostate cancer (PC), with the aim of minimizing overtreatment and maintaining the quality of life. However, concerns remain about identifying "aggressive prostate cancer" within the active surveillance cohort, which refers to cancers with a higher potential for progression. Previous studies are predictors of aggressive PC during active surveillance. To address this, a personalized risk-based follow-up approach that integrates clinical data, biomarkers, and genetic factors using risk calculators was proposed. This approach enables an efficient risk assessment and the early detection of disease progression, minimizes unnecessary interventions, and improves patient management and outcomes. As active surveillance indications expand, the importance of identifying aggressive PC through a personalized risk-based follow-up is expected to increase.

mpMRI Interpretation in Active Surveillance for Prostate Cancer-An overview of the PRECISE score

Active surveillance (AS) is now included in all major guidelines for patients with low-risk PCa and selected patients with intermediate-risk PCa. Several studies have highlighted the potential benefit of multiparametric magnetic resonance imaging (mpMRI) in AS and it has been adopted in some guidelines. However, uncertainty remains about whether serial mpMRI can help to safely reduce the number of required repeat biopsies under AS. In 2017, the European School of Oncology initiated the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) panel which proposed the PRECISE scoring system to assess the likelihood of radiological tumor progression on serial mpMRI. The PRECISE scoring system remains the only major system evaluated in multiple publications. In this review article, we discuss the current body of literature investigating the application of PRECISE as it is not as yet an established standard in mpMRI reporting. We delineate the strengths of PRECISE and its potential added value. Also, we underline potential weaknesses of the PRECISE scoring system, which might be tackled in future versions to further increase its value in AS.

Upgrading on Per Protocol versus For Cause surveillance prostate biopsies: An opportunity to decreasing the burden of active surveillance

BACKGROUND

Most prostate cancer (PC) active surveillance (AS) protocols recommend "Per Protocol" surveillance biopsy (PPSBx) every 1-3 years, even if clinical and imaging parameters remained stable. Herein, we compared the incidence of upgrading on biopsies that met criteria for "For Cause" surveillance biopsy (FCSBx) versus PPSBx.

METHODS

We retrospectively reviewed men with GG1 PC on AS in the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry. Surveillance prostate biopsies obtained 1 year after diagnosis were classified as either PPSBx or FCSBx. Biopsies were retrospectively deemed FCSBx if any of these criteria were met: PSA velocity > 0.75 ng/mL/year; rise in PSA > 3 ng from baseline; surveillance magnetic resonance imaging (MRI) (sMRI) with a PIRADS ≥ 4; change in DRE. Biopsies were classified PPSBx if none of these criteria were met. The primary outcome was upgrading to ≥GG2 or ≥GG3 on surveillance biopsy. The secondary objective was to assess for the association of reassuring (PIRADS ≤ 3) confirmatory or surveillance MRI findings and upgrading for patients undergoing PPSBx. Proportions were compared with the chi-squared test.

RESULTS

We identified 1773 men with GG1 PC in MUSIC who underwent a surveillance biopsy. Men meeting criteria for FCSBx had more upgrading to ≥GG2 (45%) and ≥GG3 (12%) compared with those meeting criteria for PPSBx (26% and 4.9%, respectively, p < 0.001 and p < 0.001). Men with a reassuring confirmatory or surveillance MRI undergoing PPSBx had less upgrading to ≥GG2 (17% and 17%, respectively) and ≥GG3 (2.9% and 1.8%, respectively) disease compared with men without an MRI (31% and 7.4%, respectively).

CONCLUSIONS

Patients undergoing PPSBx had significantly less upgrading compared with men undergoing FCSBx. Confirmatory and surveillance MRI seem to be valuable tools to stratify the intensity of surveillance biopsies for men on AS. These data may help inform the development of a risk-stratified, data driven AS protocol.

Surveillance Value of Apparent Diffusion Coefficient Maps: Multiparametric MRI in Active Surveillance of Prostate Cancer

BACKGROUND

This study aims to establish the value of apparent diffusion coefficient maps and other magnetic resonance sequences for active surveillance of prostate cancer. The study included 530 men with an average age of 66, who were under surveillance for prostate cancer. We have used multiparametric magnetic resonance imaging with subsequent transperineal biopsy (TPB) to verify the imaging findings.

RESULTS

We have observed a level of agreement of 67.30% between the apparent diffusion coefficient (ADC) maps, other magnetic resonance sequences, and the biopsy results. The sensitivity of the apparent diffusion coefficient is 97.14%, and the specificity is 37.50%. According to our data, apparent diffusion coefficient is the most accurate sequence, followed by diffusion imaging in prostate cancer detection.

CONCLUSIONS

Based on our findings we advocate that the apparent diffusion coefficient should be included as an essential part of magnetic resonance scanning protocols for prostate cancer in at least bi-parametric settings. The best option will be apparent diffusion coefficient combined with diffusion imaging and T2 sequences. Further large-scale prospective controlled studies are required to define the precise role of multiparametric and bi-parametric magnetic resonance in the active surveillance of prostate cancer.

Clinical outcomes of intraductal carcinoma or cribriform in radical prostatectomy specimens of men opting for active surveillance: data from the PRIAS-JAPAN study

BACKGROUND

Among early stage prostate cancer patients, intraductal carcinoma of the prostate (IDC-P) and invasive cribriform are key prognostic factors; however, their presence and clinical significance following active surveillance (AS) are unknown. In men who opted for AS, we aimed to examine the presence and impact of IDC-P or cribriform, utilizing radical prostatectomy (RP) specimens.

METHODS

We re-reviewed 137 RP specimens available in the PRIAS-JAPAN prospective cohort between January 2010 and September 2020. We assessed the presence of IDC-P or cribriform, and compared the patients' characteristics and prostate-specific antigen (PSA) recurrence-free survival after RP between groups with and without IDC-P or cribriform. In addition, we examined the predictive factors associated with IDC-P or cribriform.

RESULTS

The percentage of patients with IDC-P or cribriform presence was 34.3% (47 patients). IDC-P or cribriform pattern was more abundant in the higher Gleason grade group in RP specimens (P < 0.001). The rates of PSA recurrence-free survival were significantly lower in the IDC-P or cribriform groups than in those without them (log rank P = 0.0211). There was no association between IDC-P or cribriform on RP with the Prostate Imaging-Reporting and Data System (PI-RADS) 4,5 score on magnetic resonance imaging (MRI) before RP even with adjustments for other covariates (OR, 1.43; 95% confidence interval [CI] 0.511-3.980, P = 0.497).

CONCLUSIONS

IDC-P or cribriform comprised approximately one-third of all RP specimens in men who underwent RP following AS, confirming their prognostic significance.

Biomarkers of Aggressive Prostate Cancer at Diagnosis

In the United States, prostate cancer (CaP) remains the second leading cause of cancer deaths in men. CaP is predominantly indolent at diagnosis, with a small fraction (25-30%) representing an aggressive subtype (Gleason score 7-10) that is prone to metastatic progression. This fact, coupled with the criticism surrounding the role of prostate specific antigen in prostate cancer screening, demonstrates the current need for a biomarker(s) that can identify clinically significant CaP and avoid unnecessary biopsy procedures and psychological implications of being diagnosed with low-risk prostate cancer. Although several diagnostic biomarkers are available to clinicians, very few comparative trials have been performed to assess the clinical effectiveness of these biomarkers. It is of note, however, that a majority of these clinical trials have been over-represented by men of Caucasian origin, despite the fact that African American men have a 1.7 times higher incidence and 2.1 times higher rate of mortality from prostate cancer. Biomarkers for CaP diagnosis based on the tissue of origin include urine-based gene expression assays (PCA3, Select MDx, ExoDx Prostate IntelliScore, Mi-Prostate Score, PCA3-PCGEM1 gene panel), blood-based protein biomarkers (4K, PHI), and tissue-based DNA biomarker (Confirm MDx). Another potential direction that has emerged to aid in the CaP diagnosis include multi-parametric magnetic resonance imaging (mpMRI) and bi-parametric magnetic resonance imaging (bpMRI), which in conjunction with clinically validated biomarkers may provide a better approach to predict clinically significant CaP at diagnosis. In this review, we discuss some of the adjunctive biomarker tests along with newer imaging modalities that are currently available to help clinicians decide which patients are at risk of having high-grade CaP on prostate biopsy with the emphasis on clinical utility of the tests across African American (AA) and Caucasian (CA) men.

A Multivariable Approach Using Magnetic Resonance Imaging to Avoid a Protocol-based Prostate Biopsy in Men on Active Surveillance for Prostate Cancer-Data from the International Multicenter Prospective PRIAS Study

BACKGROUND

There is ongoing discussion whether a multivariable approach including magnetic resonance imaging (MRI) can safely prevent unnecessary protocol-advised repeat biopsy during active surveillance (AS).

OBJECTIVE

To determine predictors for grade group (GG) reclassification in patients undergoing an MRI-informed prostate biopsy (MRI-Bx) during AS and to evaluate whether a confirmatory biopsy can be omitted in patients diagnosed with upfront MRI.

DESIGN, SETTING, AND PARTICIPANTS

The Prostate cancer Research International: Active Surveillance (PRIAS) study is a multicenter prospective study of patients on AS (www.prias-project.org). We selected all patients undergoing MRI-Bx (targeted ± systematic biopsy) during AS.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A time-dependent Cox regression analysis was used to determine the predictors of GG progression/reclassification in patients undergoing MRI-Bx. A sensitivity analysis and a multivariable logistic regression analysis were also performed.

RESULTS AND LIMITATIONS

A total of 1185 patients underwent 1488 MRI-Bx sessions. The time-dependent Cox regression analysis showed that age (per 10 yr, hazard ratio [HR] 0.84 [95% confidence interval {CI} 0.71-0.99]), MRI outcome (Prostate Imaging Reporting and Data System [PIRADS] 3 vs negative HR 2.46 [95% CI 1.56-3.88], PIRADS 4 vs negative HR 3.39 [95% CI 2.28-5.05], and PIRADS 5 vs negative HR 4.95 [95% CI 3.25-7.56]), prostate-specific antigen (PSA) density (per 0.1 ng/ml cm³, HR 1.20 [95% CI 1.12-1.30]), and percentage positive cores on the last systematic biopsy (per 10%, HR 1.16 [95% CI 1.10-1.23]) were significant predictors of GG reclassification. Of the patients with negative MRI and a PSA density of <0.15 ng/ml cm³ (n = 315), 3% were reclassified to GG ≥2 and 0.6% to GG ≥3. At the confirmatory biopsy, reclassification to GG ≥2 and ≥3 was observed in 23% and 7% of the patients diagnosed without upfront MRI and in 19% and 6% of the patients diagnosed with upfront MRI, respectively. The multivariable analysis showed no significant difference in upgrading at the confirmatory biopsy between patients diagnosed with or without upfront MRI.

CONCLUSIONS

Age, MRI outcome, PSA density, and percentage positive cores are significant predictors of reclassification at an MRI-informed biopsy. Patients with negative MRI and a PSA density of <0.15 ng/ml cm³ can safely omit a protocol-based prostate biopsy, whereas in other patients, a multivariable approach is advised. Being diagnosed with upfront MRI appears not to significantly affect reclassification risk; hence, a confirmatory MRI-Bx cannot totally be omitted yet.

PATIENT SUMMARY

A protocol-based prostate biopsy while on active surveillance can be omitted in patients with negative magnetic resonance imaging (MRI) and prostate-specific antigen density <0.15 ng/ml cm³. A confirmatory biopsy cannot simply be omitted in all patients diagnosed with upfront MRI.

Improving multiparametric MR-transrectal ultrasound guided fusion prostate biopsies with hyperpolarized 13 C pyruvate metabolic imaging: A technical development study

PURPOSE

To develop techniques and establish a workflow using hyperpolarized carbon-13 (13 C) MRI and the pyruvate-to-lactate conversion rate (kPL ) biomarker to guide MR-transrectal ultrasound fusion prostate biopsies.

METHODS

The integrated multiparametric MRI (mpMRI) exam consisted of a 1-min hyperpolarized 13 C-pyruvate EPI acquisition added to a conventional prostate mpMRI exam. Maps of kPL values were calculated, uploaded to a picture archiving and communication system and targeting platform, and displayed as color overlays on T2 -weighted anatomic images. Abdominal radiologists identified 13 C research biopsy targets based on the general recommendation of focal lesions with kPL  >0.02(s-1 ), and created a targeting report for each study. Urologists conducted transrectal ultrasound-guided MR fusion biopsies, including the standard 1 H-mpMRI targets as well as 12-14 core systematic biopsies informed by the research 13 C-kPL targets. All biopsy results were included in the final pathology report and calculated toward clinical risk.

RESULTS

This study demonstrated the safety and technical feasibility of integrating hyperpolarized 13 C metabolic targeting into routine 1 H-mpMRI and transrectal ultrasound fusion biopsy workflows, evaluated via 5 men (median age 71 years, prostate-specific antigen 8.4 ng/mL, Cancer of the Prostate Risk Assessment score 2) on active surveillance undergoing integrated scan and subsequent biopsies. No adverse event was reported. Median turnaround time was less than 3 days from scan to 13 C-kPL targeting, and scan-to-biopsy time was 2 weeks. Median number of 13 C targets was 1 (range: 1-2) per patient, measuring 1.0 cm (range: 0.6-1.9) in diameter, with a median kPL of 0.0319 s-1 (range: 0.0198-0.0410).

CONCLUSIONS

This proof-of-concept work demonstrated the safety and feasibility of integrating hyperpolarized 13 C MR biomarkers to the standard mpMRI workflow to guide MR-transrectal ultrasound fusion biopsies.

Expanding Active Surveillance Criteria for Low- and Intermediate-risk Prostate Cancer: Can We Accurately Predict the Risk of Misclassification for Patients Diagnosed by Multiparametric Magnetic Resonance Imaging–targeted Biopsy?

Models predicting the risk of adverse pathology (ie, International Society of Urological Pathology [ISUP] grade group ≥3, pT3, and/or pN1) among patients operated by radical prostatectomy (RP) have been proposed to expand active surveillance (AS) inclusion criteria. We aimed to test these models in a set of 1062 low-risk and favorable intermediate-risk prostate cancer (PCa) patients diagnosed by multiparametric magnetic resonance imaging (MRI) and MRI-targeted biopsy. We hypothesized that the inclusion of radiological features into a novel model would improve patient selection. Performance was assessed using discrimination, calibration, and decision curve analysis (DCA). Available models were characterized by poor discrimination (areas under the receiver operating characteristic curve [AUCs] of 59% and 60%), underestimation of predicted risk on calibration plots, and a small amount of net benefit against a probability threshold of 40-50% at the DCA. The development of a novel model slightly improved discrimination (AUC of 63% vs 59%, p = 0.001, and 63% vs 60%, p = 0.07) and net benefit against threshold probabilities of ≥30%. This first multicenter study demonstrated the poor performance of models predicting adverse pathology and that implementation of MRI and MRI-targeted biopsy in this setting was not associated with a clear improvement in patient selection. Patients harboring low-risk or favorable intermediate-risk PCa and candidates for RP cannot be referred accurately to an AS program without a non-negligible risk of misclassification. PATIENT SUMMARY: We tested prediction models that could expand the selection of prostate cancer patients for active surveillance. Models were inaccurate and associated with a high risk of misclassification despite the implementation of multiparametric magnetic resonance imaging and targeted biopsies.

Testosterone therapy in prostate cancer: is it still a controversy?

PURPOSE OF REVIEW

The benefits of testosterone therapy (TTh) in the hypogonadal male can be dramatic. Historically, TTh has been contraindicated in prostate cancer (PCa). Current evidence has redefined our understanding of the influence serum testosterone has on prostatic androgen activity. Increasing numbers of hypogonadal men with coexisting PCa emphasizes the importance of describing those who may safely receive TTh. This review aims to present literature that evaluates the efficacy and safety of TTh in men with coexisting PCa.

RECENT FINDINGS

Our study, a comprehensive review of published literature regarding TTh in men with a history of PCa, consisted of studies conducted from the 1940s to 2022. Our review discusses evidence in accordance with previous studies that TTh has a role in patients with localized PCa as it has not been reported to increase rates of recurrence or progression of PCa.

SUMMARY

The use of TTh in hypongonadal men with a localized PCa has been shown to have positive clinical outcomes without increasing the rate of disease progression or recurrence. Further research, in a randomized controlled setting, is warranted.

Active Surveillance in Intermediate-Risk Prostate Cancer: A Review of the Current Data

Simple Summary

AS is an option for the initial management of selected patients with intermediate-risk PC. The proper way to predict which men will have an aggressive clinical course or indolent PC who would benefit from AS has not been unveiled. Genetics and MRI can help in the decision-making, but it remains unclear which men would benefit from which tests. In addition, there are several differences between AS protocols in inclusion criteria, monitoring follow-up, and triggers for active treatment. Large series and a few RCTs are under investigation, and more research is needed to establish an optimal therapeutic strategy for patients with intermediate-risk PC. This study summarizes the current data on patients with intermediate-risk PC under AS, recent findings, and discusses future directions.

Abstract

Active surveillance (AS) is a monitoring strategy to avoid or defer curative treatment, minimizing the side effects of radiotherapy and prostatectomy without compromising survival. AS in intermediate-risk prostate cancer (PC) has increasingly become used. There is heterogeneity in intermediate-risk PC patients. Some of them have an aggressive clinical course and require active treatment, while others have indolent disease and may benefit from AS. However, intermediate-risk patients have an increased risk of metastasis, and the proper way to select the best candidates for AS is unknown. In addition, there are several differences between AS protocols in inclusion criteria, monitoring follow-up, and triggers for active treatment. A few large series and randomized trials are under investigation. Therefore, more research is needed to establish an optimal therapeutic strategy for patients with intermediate-risk disease. This study summarizes the current data on patients with intermediate-risk PC under AS, recent findings, and discusses future directions.

The current role of MRI for guiding active surveillance in prostate cancer

Active surveillance (AS) is the recommended treatment option for low-risk and favourable intermediate-risk prostate cancer management, preserving oncological and functional outcomes. However, active monitoring using relevant parameters in addition to the usual clinical, biological and pathological considerations is necessary to compensate for initial undergrading of the tumour or to detect early progression without missing the opportunity to provide curative therapy. Indeed, several studies have raised concerns about inadequate biopsy sampling at diagnosis. However, the implementation of baseline MRI and targeted biopsy have led to improved initial stratification of low-risk disease; baseline MRI correlates well with disease characteristics and AS outcomes. The use of follow-up MRI during the surveillance phase also raises the question of the requirement for serial biopsies in the absence of radiological progression and the possibility of using completely MRI-based surveillance, with triggers for biopsies based solely on MRI findings. This concept of a tailored-risk, imaging-based monitoring strategy is aimed at reducing invasive procedures. However, the abandonment of serial biopsies in the absence of MRI progression can probably not yet be recommended in routine practice, as the data from real-life cohorts are heterogeneous and inconclusive. Thus, the evolution towards a routine, fully MRI-guided AS pathway has to be preceded by ensuring quality programme assessment for MRI reading and by demonstrating its safety in prospective trials.

Magnetic Resonance Imaging-Guided Biopsy in Active Surveillance of Prostate Cancer

PURPOSE

The underlying premise of prostate cancer active surveillance (AS) is that cancers likely to metastasize will be recognized and eliminated before cancer-related disease can ensue. Our study was designed to determine the prostate cancer upgrading rate when biopsy guided by magnetic resonance imaging (MRGBx) is used before entry and during AS.

MATERIALS AND METHODS

The cohort included 519 men with low- or intermediate-risk prostate cancer who enrolled in prospective studies (NCT00949819 and NCT00102544) between February 2008 and February 2020. Subjects were preliminarily diagnosed with Gleason Grade Group (GG) 1 cancer; AS began when subsequent MRGBx confirmed GG1 or GG2. Participants underwent confirmatory MRGBx (targeted and systematic) followed by surveillance MRGBx approximately every 12 to 24 months. The primary outcome was tumor upgrading to ≥GG3.

RESULTS

Upgrading to ≥GG3 was found in 92 men after a median followup of 4.8 years (IQR 3.1-6.5) after confirmatory MRGBx. Upgrade-free probability after 5 years was 0.85 (95% CI 0.81-0.88). Cancer detected in a magnetic resonance imaging lesion at confirmatory MRGBx increased risk of subsequent upgrading during AS (HR 2.8; 95% CI 1.3-6.0), as did presence of GG2 (HR 2.9; 95% CI 1.1-8.2) In men who upgraded ≥GG3 during AS, upgrading was detected by targeted cores only in 27%, systematic cores only in 25% and both in 47%. In 63 men undergoing prostatectomy, upgrading from MRGBx was found in only 5 (8%).

CONCLUSIONS

When AS begins and follows with MRGBx (targeted and systematic), upgrading rate (≥GG3) is greater when tumor is initially present within a magnetic resonance imaging lesion or when pathology is GG2 than when these features are absent.

The utility of prostate MRI within active surveillance: description of the evidence

Purpose

We present an overview of the literature regarding the use of MRI in active surveillance of prostate cancer.

Methods

Both MEDLINE^® and Cochrane Library were queried up to May 2020 for studies of men on active surveillance with MRI and later confirmatory biopsy. The terms studied were ‘prostate cancer’ as the anchor followed by two of the following: active surveillance, surveillance, active monitoring, MRI, NMR, magnetic resonance imaging,  MRI, and multiparametric MRI. Studies were excluded if pathologic reclassification (GG1 →  ≥ GG2) and PI-RADS or equivalent was not reported.

Results

Within active surveillance, baseline MRI is effective for identifying clinically significant prostate cancer and thus associated with fewer reclassification events. A positive initial MRI (≥ PI-RADS 3) with GG1 identified at biopsy has a positive predictive value (PPV) of 35–40% for reclassification by 3 years. MRI possessed a stronger negative predictive value, with a negative MRI (≤ PI-RADS 2) yielding a negative predictive value of up to 85% at 3 years. Surveillance MRI, obtained after initial biopsy, yielded a PPV of 11–65% and NPV of 85–95% for reclassification.

Conclusion

MRI is useful for initial risk stratification of prostate cancer in men on active surveillance, especially if MRI is negative when imaging is obtained during surveillance. While useful, MRI cannot replace biopsy and further research is necessary to fully integrate MRI into active surveillance.

Association of MyProstateScore (MPS) with prostate cancer grade in the radical prostatectomy specimen

BACKGROUND

To evaluate the association between urinary MyProstateScore (MPS) and pathologic grade group (GG) at surgery in men diagnosed with GG1 prostate cancer (PCa) on biopsy.

METHODS

Using an institutional biospecimen protocol, we identified men with GG1 PCa on biopsy and PSA ≤10 ng/ml who underwent radical prostatectomy (RP) at the University of Michigan. MPS was retrospectively calculated using prospectively collected, post-DRE urine samples. The primary outcome was upgrading on RP pathology, defined as GG ≥ 2. The associations of MPS, PSA, and PSA density (PSAD) with upgrading were assessed on univariable logistic regression, and the predictive accuracy of each marker was estimated by the area under the receiver operating characteristic curve (AUC).

RESULTS

There were 52 men with urinary specimens available that met study criteria, based on biopsy Gleason Grade and specimen collection. At RP, 17 men (33%) had GG1 cancer and 35 (67%) had GG ≥ 2 cancer. Preoperative MPS was significantly higher in patients with GG ≥ 2 cancer at surgery (median 37.8 [IQR, 22.2-52.4]) as compared to GG1 (19.3 [IQR, 9.2-29.4]; P = 0.001). On univariable logistic regression, increasing MPS values were significantly associated with upgrading (odds ratio 1.07 per one-unit MPS increase, 95% confidence interval 1.02-1.12, P = 0.004), while PSA and PSAD were not significantly associated with upgrading. Similarly, the discriminative ability of the MPS model (AUC 0.78) for upgrading at RP was higher compared to models based on PSA (AUC 0.52) and PSAD (AUC 0.62).

CONCLUSIONS

In men diagnosed with GG1 PCa who underwent surgery, MPS was significantly associated with RP cancer grade. In this limited cohort of men, these findings suggest that MPS could help identify patients with undetected high-grade cancer. Additional studies are needed to better characterize this association.

Repeat MRI during active surveillance: natural history of prostatic lesions and upgrading rates

OBJECTIVES

To assess upgrading rates in patients on active surveillance (AS) for prostate cancer (PCa) after serial multiparametric magnetic resonance imaging (mpMRI).

METHODS

We conducted a retrospective analysis of 558 patients. Five different criteria for mpMRI progression were used: 1) a Prostate Imaging Reporting and Data System (PI-RADS) score increase; 2) a lesion size increase; 3) an extraprostatic extension score increase; 4) overall mpMRI progression; and 5) the number of criteria met for mpMRI progression (0 vs 1 vs 2-3). In addition, two definitions of PCa upgrading were evaluated: 1) International Society of Urological Pathology Grade Group (ISUP GG) ≥2 with >10% of pattern 4 and 2) ISUP GG ≥ 3. Estimated annual percent changes methodology was used to show the temporal trends of mpMRI progression criteria. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of mpMRI progression criteria were also analysed. Multivariable logistic regression models tested PCa upgrading rates.

RESULTS

Lower rates over time for all mpMRI progression criteria were observed. The NPV of serial mpMRI scans ranged from 90.5% to 93.5% (ISUP GG≥2 with >10% of pattern 4 PCa upgrading) and from 98% to 99% (ISUP GG≥3 PCa upgrading), depending on the criteria used for mpMRI progression. A prostate-specific antigen density (PSAD) threshold of 0.15 ng/mL/mL was used to substratify those patients who would be able to skip a prostate biopsy. In multivariable logistic regression models assessing PCa upgrading rates, all five mpMRI progression criteria achieved independent predictor status.

CONCLUSION

During AS, approximately 27% of patients experience mpMRI progression at first repeat MRI. However, the rates of mpMRI progression decrease over time at subsequent mpMRI scans. Patients with stable mpMRI findings and with PSAD < 0.15 ng/mL/mL could safely skip surveillance biopsies. Conversely, patients who experience mpMRI progression should undergo a prostate biopsy.

Clinical implementation of pre-biopsy magnetic resonance imaging pathways for the diagnosis of prostate cancer

Objective

To assess the outcomes of pre‐biopsy magnetic resonance imaging (MRI) pathways, as a tool in biopsy‐naïve men with suspicion of prostate cancer, in routine clinical practice. Secondary outcomes included a comparison of transrectal MRI‐directed biopsy (TR‐MRDB) and transperineal (TP)‐MRDB in men with suspicious MRI.

Patients and Methods

We retrospectively assessed a two‐centre cohort of consecutive biopsy‐naïve men with suspicion of prostate cancer who underwent a Prostate Imaging‐Reporting and Data System version 2 (PI‐RADS v2) compliant pre‐biopsy MRI in a single, high‐volume centre between 2015 and 2019 (Centre 1). Men with suspicious MRI scans underwent TR‐MRDB in Centre 1 and TP‐MRDB with additional random biopsies (RB) in Centre 2. The MRI and histopathology were assessed in the same institution (Centre 1). Outcomes included: (i) overall detection rates of Grade Group (GG) 1, GG ≥2, and GG ≥3 cancer in men with suspicious MRI; (ii) Biopsy‐avoidance due to non‐suspicious MRI; and (iii) Cancer detection rates and biopsy‐related complications between TR‐ and TP‐MRDB. To reduce confounding bias for MRDB comparisons, inverse probability weighting (IPW) was performed for age, digital rectal examination, prostate‐specific antigen (PSA), prostate volume, PSA density, and PI‐RADS category.

Results

Of the 2597 men included, the overall GG 1, GG ≥2, and GG ≥3 prevalence was 8% (210/2597), 27% (697/2597), and 15% (396/2597), respectively. Biopsy was avoided in 57% (1488/2597) of men. After IPW, the GG 1, GG ≥2 and GG ≥3 detection rates after TR‐ and TP‐MRDB were comparable at 24%, 57%, and 32%; and 18%, 64%, and 38%, respectively; with mean differences of −5.7% (95% confidence interval [CI] −13% to 1.4%), 6.1% (95% CI −2.1% to 14%), and 5.7% (95% CI −1.7% to 13%). Complications were similar in TR‐MRDB (0.50%) and TP‐MRDB with RB (0.62%; mean difference 0.11%, 95% CI −0.87% to 1.1%).

Conclusion

This high‐volume, two‐centre study shows pre‐biopsy MRI as a decision tool is implementable in daily clinical practice. Compared to recent trials, a substantially higher biopsy avoidance rate was achieved without compromising GG ≥2/GG ≥3 detection and coinciding with lower over detection rates of GG 1 cancer. Prostate cancer detection and complication rates were comparable for TR‐ and TP‐MRDB.

Active surveillance for prostate cancer

Many men diagnosed with localized prostate cancer can postpone definitive treatment without raising their risk of metastasis or death from disease. Active surveillance (AS) is a method of monitoring select men, with the option of switching to active treatment upon signs of progression, thereby avoiding the well-known side-effects of surgery and radiotherapy. This review analyzes the data from long-running AS cohorts to determine the safety and efficacy of AS. We conducted a narrative review of recently published data, including 14 articles from 13 AS cohorts. The cohorts used varying inclusion criteria, with reported differences in clinical T stage and Gleason Score (Grade Group), among other features. Some studies (n=5) limited their cohorts to low-risk patients, while others (n=8) also included intermediate-risk patients. The heterogeneity of the cohorts produced mixed results, with the risk of prostate cancer metastasis ranging from 0.1–1.0% at 10 years and the risk of prostate cancer mortality ranging from 0–1.9% at 10 years. However, the majority of studies reported risks of less than 0.5% at 10 years for both metastasis and death. For most cohorts, half of men remained untreated for 5–10 years, with estimates ranging from 37% receiving active treatment in the Toronto cohort to 73% in the Prostate Cancer Research International AS (PRIAS) study. Current data do not support the use of negative magnetic resonance imaging (MRI) to avoid scheduled biopsy. Taken together, the data collected from these AS cohorts suggests that AS is a safe approach for men with low-grade prostate cancer and some men with intermediate risk disease. AS should be more broadly implemented for eligible patients to avoid the decreases in quality of life from undergoing active treatment. Studies expanding the inclusion criteria and further defining a subset of men with favorable intermediate-risk prostate cancer who might safely benefit from AS are needed to assess the long-term outcomes of using AS in intermediate-risk groups.

Reliability of Serial Prostate Magnetic Resonance Imaging to Detect Prostate Cancer Progression During Active Surveillance: A Systematic Review and Meta-analysis

CONTEXT

Although magnetic resonance imaging (MRI) is broadly implemented into active surveillance (AS) protocols, data on the reliability of serial MRI in order to help guide follow-up biopsy are inconclusive.

OBJECTIVE

To assess the diagnostic estimates of serial prostate MRI for prostate cancer (PCa) progression during AS.

EVIDENCE ACQUISITION

We systematically searched PubMed, Scopus, and Web of Science databases to select studies analyzing the association between changes on serial prostate MRI and PCa progression during AS. We included studies that provided data for MRI progression, which allowed us to calculate diagnostic estimates. We compared Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) accuracy with institution-specific definitions.

EVIDENCE SYNTHESIS

We included 15 studies with 2240 patients. Six used PRECISE criteria and nine institution-specific definitions of MRI progression. The pooled PCa progression rate, which included histological progression to Gleason grade ≥2, was 27%. The pooled sensitivity and specificity were 0.59 (95% confidence interval [CI] 0.44-0.73) and 0.75 (95% CI 0.66-0.84) respectively. There was significant heterogeneity between included studies. Depending on PCa progression prevalence, the pooled negative predictive value for serial prostate MRI ranged from 0.81 (95% CI 0.73-0.88) to 0.88 (95% CI 0.83-0.93) and the pooled positive predictive value ranged from 0.37 (95% CI 0.24-0.54) to 0.50 (95% CI 0.36-0.66). There were no significant differences in the pooled sensitivity (p = 0.37) and specificity (p = 0.74) of PRECISE and institution-specific schemes.

CONCLUSIONS

Serial MRI still should not be considered a sole factor for excluding PCa progression during AS, and changes on MRI are not accurate enough to indicate PCa progression. There was a nonsignificant trend toward improved diagnostic estimates of PRECISE recommendations. These findings highlight the need to further define the optimal triggers and timing of biopsy during AS, as well as the need for optimizing the quality, interpretation, and reporting of serial prostate MRI.

PATIENT SUMMARY

Our study suggests that serial prostate magnetic resonance imaging (MRI) alone in patients on active surveillance is not accurate enough to reliably rule out or rule in prostate cancer progression. Other clinical factors and biomarkers along with serial MRI are required to safely tailor the intensity of follow-up biopsies.

The clinical impact of strict criteria for active surveillance of prostate cancer in Korean population: Results from a prospective cohort

Purpose

To evaluate the clinical impact of strict selection criteria for active surveillance (AS) of prostate cancer in a Korean population.

Materials and Methods

A single-center, prospectively collected AS cohort from December 2016 to February 2019 was used. Following pre-determined criteria, patients were categorized into “strict AS” and “non-strict AS” groups. Clinicopathological progression-free survival (PFS) and treatment-free survival (TFS) of the two groups were compared using the Kaplan–Meier curve and log-rank test. Age-adjusted hazard ratios for clinicopathological progression was calculated using Cox proportional regression analysis.

Results

Of 54 eligible patients, 25 and 29 were assigned to “strict AS” and “non-strict AS,” respectively. Clinicopathological progression and definitive treatment rates were 24.0% (6 of 25 patients) vs. 51.7% (15 of 29 patients) and 32.0% (8 of 25 patients) vs. 62.1% (18 of 29 patients) in “strict AS” and “non-strict AS” groups. Progress to high-risk cancer (pathologic T3 or surgical Gleason Grade 2 over) in radical prostatectomy was higher in “non-strict AS” than “strict AS”. PFS (mean 34.6±2.9 mo vs. 22.6±2.7 mo; p=0.025) and TFS (mean 31.8±3.2 mo vs. 19.6±2.4 mo; p=0.018) favor the “strict AS” group than “non-strict AS” group. Age-adjusted hazard ratio for clinicopathological progression of strict criteria was 0.36 (95% confidence interval, 0.14–0.94; p=0.04).

Conclusions

PFS and TFS were better in the “strict AS” group than in the “non-strict AS” group. This finding should be informed to relevant patients during decision making and considered in Korean guidelines.

What is the effect of MRI with targeted biopsies on the rate of patients discontinuing active surveillance? A reflection of the use of MRI in the PRIAS study

BACKGROUND

The reduction of overtreatment by active surveillance (AS) is limited in patients with low-risk prostate cancer (PCa) due to high rates of patients switching to radical treatment. MRI improves biopsy accuracy and could therewith affect inclusion in or continuation of AS. We aim to assess the effect of MRI with target biopsies on the total rate of patients discontinuing AS, and in particular discontinuation due to Grade Group (GG) reclassification.

METHODS

Three subpopulations included in the prospective PRIAS study with GG 1 were studied. Group A consists of patients diagnosed before 2009 without MRI before or during AS. Group B consists of patients diagnosed without MRI, but all patients underwent MRI within 6 months after diagnosis. Group C consists of patients who underwent MRI before diagnosis and during follow-up. We used cumulative incidence curves to estimate the rates of discontinuation.

RESULTS

In Group A (n = 500), the cumulative probability of discontinuing AS at 2 years is 27.5%; GG reclassification solely accounted for 6.9% of the discontinuation. In Group B (n = 351) these numbers are 30.9 and 22.8%, and for Group C (n = 435) 24.2 and 13.4%. The three groups were not randomized, however, baseline characteristics are highly comparable.

CONCLUSIONS

Performing an MRI before starting AS reduces the cumulative probability of discontinuing AS at 2 years. Performing an MRI after already being on AS increases the cumulative probability of discontinuing AS in comparison to not performing an MRI, especially because of an increase in GG reclassification. These results suggest that the use of MRI could lead to more patients being considered unsuitable for AS. Considering the excellent long-term cancer-specific survival of AS before the MRI era, the increased diagnostic accuracy of MRI could potentially lead to more overtreatment if definitions and treatment options of significant PCa are not adapted.

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.

Changes in Magnetic Resonance Imaging Using the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation Criteria to Detect Prostate Cancer Progression for Men on Active Surveillance

BACKGROUND

The ability of serial magnetic resonance imaging (MRI) to capture pathologic progression during active surveillance (AS) remains in question.

OBJECTIVE

To determine whether changes in MRI are associated with pathologic progression for patients on AS.

DESIGN, SETTING, AND PARTICIPANTS

From July 2007 through January 2020, we identified all patients evaluated for AS at our institution. Following confirmatory biopsy, a total of 391 patients who underwent surveillance MRI and biopsy at least once were identified (median follow-up of 35.6 mo, interquartile range 19.7-60.6).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

All MRI intervals were scored using the "Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation" (PRECISE) criteria, with PRECISE scores =4 considered a positive change in MRI. A generalized estimating equation-based logistic regression analysis was conducted for all intervals with a PRECISE score of <4 to determine the predictors of Gleason grade group (GG) progression despite stable MRI.

RESULTS AND LIMITATIONS

A total of 621 MRI intervals were scored by PRECISE and validated by biopsy. The negative predictive value of stable MRI (PRECISE score <4) was greatest for detecting GG1 to?=?GG3 disease (0.94 [0.91-0.97]). If 2-yr surveillance biopsy were performed exclusively for a positive change in MRI, 3.7% (4/109) of avoided biopsies would have resulted in missed progression from GG1 to?=?GG3 disease. Prostate-specific antigen (PSA) density (odds ratio 1.95 [1.17-3.25], p?=? 0.01) was a risk factor for progression from GG1 to =GG3 disease despite stable MRI.

CONCLUSIONS

In patients with GG1 disease and stable MRI (PRECISE score <4) on surveillance, grade progression to?=?GG3 disease is not common. In patients with grade progression detected on biopsy despite stable MRI, elevated PSA density appeared to be a risk factor for progression to?=?GG3 disease.

PATIENT SUMMARY

For patients with low-risk prostate cancer on active surveillance, the risk of progressing to grade group 3 disease is low with a stable magnetic resonance image (MRI) after 2?yr. Having higher prostate-specific antigen density increases the risk of progression, despite having a stable MRI.

Serial Molecular Profiling of Low-grade Prostate Cancer to Assess Tumor Upgrading: A Longitudinal Cohort Study

BACKGROUND

The potential for low-grade (grade group 1 [GG1]) prostate cancer (PCa) to progress to high-grade disease remains unclear.

OBJECTIVE

To interrogate the molecular and biological features of low-grade PCa serially over time.

DESIGN, SETTING, AND PARTICIPANTS

Nested longitudinal cohort study in an academic active surveillance (AS) program. Men were on AS for GG1 PCa from 2012 to 2017.

INTERVENTION

Electronic tracking and resampling of PCa using magnetic resonance imaging/ultrasound fusion biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

ERG immunohistochemistry (IHC) and targeted DNA/RNA next-generation sequencing were performed on initial and repeat biopsies. Tumor clonality was assessed. Molecular data were compared between men who upgraded and those who did not upgrade to GG ≥ 2 cancer.

RESULTS AND LIMITATIONS

Sixty-six men with median age 64 yr (interquartile range [IQR], 59-69) and prostate-specific antigen 4.9 ng/mL (IQR, 3.3-6.4) underwent repeat sampling of a tracked tumor focus (median interval, 11 mo; IQR, 6-13). IHC-based ERG fusion status was concordant at initial and repeat biopsies in 63 men (95% vs expected 50%, p <  0.001), and RNAseq-based fusion and isoform expression were concordant in nine of 13 (69%) ERG+ patients, supporting focal resampling. Among 15 men who upgraded with complete data at both time points, integrated DNA/RNAseq analysis provided evidence of shared clonality in at least five cases. Such cases could reflect initial undersampling, but also support the possibility of clonal temporal progression of low-grade cancer. Our assessment was limited by sample size and use of targeted sequencing.

CONCLUSIONS

Repeat molecular assessment of low-grade tumors suggests that clonal progression could be one mechanism of upgrading. These data underscore the importance of serial tumor assessment in men pursuing AS of low-grade PCa.

PATIENT SUMMARY

We performed targeted rebiopsy and molecular testing of low-grade tumors on active surveillance. Our findings highlight the importance of periodic biopsy as a component of monitoring for cancer upgrading during surveillance.

Update on Multiparametric Prostate MRI During Active Surveillance: Current and Future Trends and Role of the PRECISE Recommendations

Active surveillance for low-to-intermediate risk prostate cancer is a conservative management approach that aims to avoid or delay active treatment until there is evidence of disease progression. In recent years, multiparametric MRI (mpMRI) has been increasingly used in active surveillance and has shown great promise in patient selection and monitoring. This has been corroborated by publication of the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation (PRECISE) recommendations, which define the ideal reporting standards for mpMRI during active surveillance. The PRECISE recommendations include a system that assigns a score from 1 to 5 (the PRECISE score) for the assessment of radiologic change on serial mpMRI scans. PRECISE scores are defined as follows: a score of 3 indicates radiologic stability, a score of 1 or 2 denotes radiologic regression, and a score of 4 or 5 indicates radiologic progression. In the present study, we discuss current and future trends in the use of mpMRI during active surveillance and illustrate the natural history of prostate cancer on serial scans according to the PRECISE recommendations. We highlight how the ability to classify radiologic change on mpMRI with use of the PRECISE recommendations helps clinical decision making.

Diagnostic Accuracy and Prognostic Value of Serial Prostate Multiparametric Magnetic Resonance Imaging in Men on Active Surveillance for Prostate Cancer

BACKGROUND

Multiparametric magnetic resonance imaging (MRI) is increasingly utilized to improve the detection of clinically significant prostate cancer. Evidence for serial MRI in men on active surveillance (AS) is lacking.

OBJECTIVE

To evaluate the role of MRI in detecting Gleason grade group (GG) ≥2 disease in confirmatory and subsequent surveillance biopsies for men on AS.

DESIGN, SETTING, AND PARTICIPANTS

This was a single-center study of men with low-risk prostate cancer enrolled in an AS cohort between 2006 and 2018. All men were diagnosed by systematic biopsy and underwent MRI prior to confirmatory ("MRI1") and subsequent surveillance ("MRI2") biopsies. MRI lesions were scored with Prostate Imaging Reporting and Data System (PI-RADS) version 2.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was biopsy upgrade to GG ≥ 2 prostate cancer, and the secondary outcome was definitive treatment. Test characteristics for PI-RADS score were calculated. Multivariable logistic and Cox proportional hazard regression models were used to determine the associations between PI-RADS score change and outcomes, on a per-examination basis.

RESULTS AND LIMITATIONS

Of 125 men with a median follow-up of 78 mo, 38% experienced an increase in PI-RADS scores. The sensitivity and positive predictive value of PI-RADS ≥3 for GG ≥ 2 disease improved from MRI1 to MRI2 (from 85% to 91% and from 26% to 49%, respectively). An increase in PI-RADS scores from MRI1 to MRI2 was associated with GG ≥ 2 (odds ratio [OR] 4.8, 95% confidence interval [CI] 1.7-13.2) compared with PI-RADS 1-3 on both MRI scans. Men with PI-RADS 4-5 lesions on both MRI scans had a higher likelihood of GG ≥ 2 than patients with PI-RADS 1-3 lesions on both (OR 3.3, 95% CI 1.3-8.6). Importantly, any increase in PI-RADS scores was independently associated with definitive treatment (hazard ratio 3.9, 95% CI 1.3-11.9). This study was limited by its retrospective, single-center design.

CONCLUSIONS

The prognostic value of MRI improves with serial examination and provides additional risk stratification. Validation in other cohorts is needed.

PATIENT SUMMARY

We looked at the role of serial prostate magnetic resonance imaging in men with low-risk prostate cancer on active surveillance at the University of California, San Francisco. We found that both consistently visible and increasingly suspicious lesions were associated with biopsy upgrade and definitive treatment.

Personalised biopsy schedules based on risk of Gleason upgrading for patients with low-risk prostate cancer on active surveillance

OBJECTIVE

To develop a model and methodology for predicting the risk of Gleason upgrading in patients with prostate cancer on active surveillance (AS) and using the predicted risks to create risk-based personalised biopsy schedules as an alternative to one-size-fits-all schedules (e.g. annually). Furthermore, to assist patients and doctors in making shared decisions on biopsy schedules, by providing them quantitative estimates of the burden and benefit of opting for personalised vs any other schedule in AS. Lastly, to externally validate our model and implement it along with personalised schedules in a ready to use web-application.

PATIENTS AND METHODS

Repeat prostate-specific antigen (PSA) measurements, timing and results of previous biopsies, and age at baseline from the world's largest AS study, Prostate Cancer Research International Active Surveillance (PRIAS; 7813 patients, 1134 experienced upgrading). We fitted a Bayesian joint model for time-to-event and longitudinal data to this dataset. We then validated our model externally in the largest six AS cohorts of the Movember Foundation's third Global Action Plan (GAP3) database (>20 000 patients, 27 centres worldwide). Using the model predicted upgrading risks; we scheduled biopsies whenever a patient's upgrading risk was above a certain threshold. To assist patients/doctors in the choice of this threshold, and to compare the resulting personalised schedule with currently practiced schedules, along with the timing and the total number of biopsies (burden) planned, for each schedule we provided them with the time delay expected in detecting upgrading (shorter is better).

RESULTS

The cause-specific cumulative upgrading risk at the 5-year follow-up was 35% in PRIAS, and at most 50% in the GAP3 cohorts. In the PRIAS-based model, PSA velocity was a stronger predictor of upgrading (hazard ratio [HR] 2.47, 95% confidence interval [CI] 1.93-2.99) than the PSA level (HR 0.99, 95% CI 0.89-1.11). Our model had a moderate area under the receiver operating characteristic curve (0.6-0.7) in the validation cohorts. The prediction error was moderate (0.1-0.2) in theGAP3 cohorts where the impact of the PSA level and velocity on upgrading risk was similar to PRIAS, but large (0.2-0.3) otherwise. Our model required re-calibration of baseline upgrading risk in the validation cohorts. We implemented the validated models and the methodology for personalised schedules in a web-application (http://tiny.cc/biopsy).

CONCLUSIONS

We successfully developed and validated a model for predicting upgrading risk, and providing risk-based personalised biopsy decisions in AS of prostate cancer. Personalised prostate biopsies are a novel alternative to fixed one-size-fits-all schedules, which may help to reduce unnecessary prostate biopsies, while maintaining cancer control. The model and schedules made available via a web-application enable shared decision-making on biopsy schedules by comparing fixed and personalised schedules on total biopsies and expected time delay in detecting upgrading.

Multiparametric magnetic resonance imaging facilitates reclassification during active surveillance for prostate cancer

OBJECTIVE

To investigate the utility of multiparametric magnetic resonance imaging (mpMRI) in the reassessment and monitoring of patients on active surveillance (AS) for Grade Group (GG) 1 prostate cancer (PCa).

PATIENTS AND METHODS

We identified, from our prospectively maintained institutional review board-approved database, 181 consecutive men enrolled on AS for GG 1 PCa who underwent at least one surveillance mpMRI followed by MRI/prostate biopsy (PBx). A subset analysis was performed among 68 patients who underwent serial (at least two) mpMRI/PBx during AS. Pathological progression (PP) was defined as upgrade to GG ≥2 on follow up biopsy.

RESULTS

Baseline MRI was performed in 34 patients (19%). At a median follow-up of 2.2 years for the overall cohort, the PP was 12% (6/49) for Prostate Imaging Reporting and Data System (PI-RADS) 1-2 lesions and 37% (48/129) for the PI-RADS ≥3 lesions. The 2-year PP-free survival rate was 84%. Surveillance prostate-specific antigen density (P < 0.001) and surveillance PI-RADS ≥3 (P = 0.002) were independent predictors of PP on reassessment MRI/PBx. In the serial MRI cohort, the 2-year PP-free survival was 95% for the No-MRI-progression group vs 85% for the MRI-progression group (P = 0.02). MRI progression was significantly higher in the PP (62%) than in the No-PP (31%) group (P = 0.04). If serial MRI were used for PCa surveillance and biopsy were triggered based only on MRI progression, 63% of PBx might be postponed at the cost of missing 12% of GG ≥2 PCa in those with stable MRI. Conversely, this strategy would miss 38% of those with upgrading to GG ≥2 PCa on biopsy. Stable serial mpMRI correlates with no reclassification to GG ≥3 PCa during AS.

CONCLUSION

On surveillance mpMRI, PI-RADS ≥3 was associated with increased risk of PCa reclassification. Surveillance biopsy based only on MRI progression may avoid a large number of biopsies at the cost of missing many PCa reclassifications.

Should we perform systematic biopsies in case of suspicious MRI for prostate cancer in 2020? A review of literature

CONTEXT

Multiparametric magnetic resonance imaging (MRI) is now recommended before performing prostate biopsies, looking for suspicious lesions to perform targeted biopsies (TB). However, the association or exclusive performance of systematic biopsies (SB), criticized for its morbidity and for the detection of insignificant cancers, remains debated.

OBJECTIVE

To perform a literature review to answer three questions: (1) In the presence of a suspicious MRI lesion, should we always perform SB in addition to TB? (2) Can we avoid SB when considering focal treatment? (3) Is there an increase in adverse events when associating SB with TB?

SOURCES

A non-systematic literature review was carried out on Medline in April 2020 using the keywords "MRI", "PROSTATE CANCER", "SYSTEMATIC BIOPSY", "TARGETED BIOPSY", "ADVERSE EVENTS". The references of the selected articles were analyzed for additional articles. Selection of Studies published in the last five years were analyzed and retained if the available data made it possible to answer one of the three questions asked.

RESULTS

In biopsy-naive patients, the added value of SB to TB for detection of significative cancer varied from +5 to+7% and was reduced to +1 to +3% in the case of a previous series of negative biopsies. For patients under active surveillance, this added value was higher, ranging from +8% to +17%. MRI has a negative predictive value of 85 to 95%, but this value drops to 55% for the detection of secondary or tertiary foci. The use of SB is necessary if focal treatment is considered. Serious complications from biopsies requiring hospitalization range from 1.4 to 6.9% and are increased by the number of previous biopsy series performed more than by the number of biopsies per series.

CONCLUSION

In the presence of a suspicious MRI lesion, SB is indicated in addition to TB but can be discussed in patients with previous negative biopsies. They are necessary if focal treatment is considered to aid surgical planning. Severe complications from biopsies do not seem to increase when SB are associated to TB, but rather with the number of biopsy series performed.

Histological findings of totally embedded robot assisted laparoscopic radical prostatectomy (RALP) specimens in 1197 men with a negative (low risk) preoperative multiparametric magnetic resonance imaging (mpMRI) prostate lobe and clinical implications

BACKGROUND

Prostate multiparametric magnetic resonance imaging (mpMRI) has become a popular initial investigation of an elevated PSA and is being incorporated into active surveillance protocols. Decisions on prostate cancer investigation and management based solely on a normal mpMRI remains controversial. Histopathological findings of a totally embedded normal mpMRI lobe are rarely described.

METHODS

A retrospective review of the histological findings of negative preoperative mpMRI lobes in men treated by robot assisted laparoscopic radical prostatectomy (RALP). Inclusion criteria included a preoperative low risk mpMRI for both lobes (Prostate Imaging-Reporting and Data System (PIRADS) ≤ 2) or one negative lobe (with a PIRADS 3-5 in the opposite lobe).

RESULTS

A single normal mpMRI lobe was identified in 1018 men (PIRADS 3-5 group). Both lobes were normal in 179 men (PIRADS ≤ 2 group). Prostate cancer was identified in 47.6% (485/1018) of the normal mpMRI lobe opposite a PIRADS 3-5 lesion, including 13.2% (134/1018) with >0.5 cc of International Society of Urologic Pathologists (ISUP) grade 2, or a higher grade cancer. ISUP grade 4-5 was only identified in 2% (20/1018). Compared to RALP histology of the PIRADS 3-5 mpMRI tumour, a pathological ISUP upgrade in the normal mpMRI lobe was identified in 58/1018 men (5.7%). In the PIRADS ≤ 2 group extraprostatic extension occurred in 19% (34/179) and seminal vesicle invasion (pT3b) in 3.9% (7/179). There was no difference in margin status between the PIRADS 3-5 and ≤2 groups (p = 0.247).

CONCLUSIONS

mpMRI underestimates tumour grade and volume compared to totally embedded histopathological analysis of RALP specimens, although ISUP grade 4-5 cancer is uncommon. Our analysis provides useful insight into the multifocality of prostate cancers, and highlights the utility of systematic biopsy, in addition to targeted biopsies. These results have ramifications for clinical decisions on prostate cancer management based solely on the mpMRI appearance, including active surveillance.

What to expect from a non-suspicious prostate MRI? A review

BACKGROUND

Many guidelines now recommend multiparametric MRI (mpMRI) prior to an initial or repeat prostate biopsy. However, clinical decision making for men with a non-suspicious mpMRI (Likert or PIRADS score 1-2) varies.

OBJECTIVES

To review the most recent literature to answer three questions. (1) Should we consider systematic biopsy if mpMRI is not suspicious? (2) Are there additional predictive factors that can help decide which patient should have a biopsy? (3) Can the low visibility of some cancers be explained and what are the implications?

SOURCES

A narrative review was performed in Medline databases using two searches with the terms "MRI" and "prostate cancer" and ("diagnosis" or "biopsy") and ("non-suspicious" or "negative" or "invisible"); "prostate cancer MRI visible". References of the selected articles were screened for additional articles.

STUDY SELECTION

Studies published in the last 5 years in English language were assessed for eligibility and selected if data was available to answer one of the three study questions.

RESULTS

Considering clinically significant cancer as ISUP grade≥2, the negative predictive value (NPV) of mpMRI in various settings and populations ranges from 76% to 99%, depending on cancer prevalence and the type of confirmatory reference test used. NPV is higher among patients with prior negative biopsy (88-96%), and lower for active surveillance patients (85-90%). The PSA density (PSAd) with a threshold of PSAd<0.15ng/ml/ml was the most studied and relevant predictive factor used in combination with mpMRI to rule out clinically significant cancer. Finally, mpMRI-invisible tumours appear to differ from a histopathological and genetic point of view, conferring clinical advantage to invisibility.

LIMITATIONS

Most published data come from expert centres and results may not be reproducible in all settings.

CONCLUSION

mpMRI has high diagnostic accuracy and in cases of negative mpMRI, PSA density can be used to determine which patient should have a biopsy. Growing knowledge of the mechanisms and genetics underlying MRI visibility will help develop more accurate risk calculators and biomarkers.

Conspicuity of prostate cancer on multiparametric magnetic resonance imaging: A cross-disciplinary translational hypothesis

Pre-biopsy multiparametric magnetic resonance imaging (mpMRI) has transformed the risk stratification and diagnostic approach for suspected prostate cancer. The majority of clinically significant prostate cancers are visible on pre-biopsy mpMRI, however, there are a subset of significant tumors that are not detected by mpMRI. The radiobiological mechanisms underpinning mpMRI-visibility and invisibility of these cancers remain uncertain. Emerging evidence suggests that mpMRI-visible tumors are enriched with molecular features associated with increased disease aggressivity and poor clinical prognosis, which is supported by short-term endpoints, such as biochemical recurrence following surgery. Furthermore, at the histopathological level, mpMRI-visible tumors appear to exhibit increased architectural and vascular density compared to mpMRI-invisible disease. It seems probable that the genomic, pathological, radiological, and clinical features of mpMRI-visible and mpMRI-invisible prostate cancers are interrelated. Here, we propose a novel cross-disciplinary theory that links genomic and molecular evidence with cellular and histopathological appearances, elucidating both the mpMRI visibility and clinical status of significant prostate cancer.

Incorporating Magnetic Resonance Imaging and Biomarkers in Active Surveillance Protocols - Results From the Prospective Stockholm3 Active Surveillance Trial (STHLM3AS)

BACKGROUND

Active surveillance (AS) for men with low-risk prostate cancer (PC) can lead to patient morbidity and healthcare overutilization. The aim of this study was to evaluate an AS protocol using the Stockholm3 test and magnetic resonance imaging (MRI) to reduce biopsy intensity.

METHODS

We conducted a prospective multicenter study of 280 invited men from a contemporary screening study (STHLM3), with Gleason Score (GS) 3 + 3 PC on a current AS protocol. Patients underwent prostate-MRI and blood sampling for analysis of the Stockholm3 test including protein biomarkers, genetic variants, and clinical variables to predict risk of GS ≥3 + 4 PC followed by systematic biopsies and targeted biopsies (for Prostate Imaging Reporting and Data System version 2 ≥3 lesions) in all men. Primary outcomes were reclassification to GS ≥3 + 4 PC and clinically significant PC (csPCa), including unfavorable intermediate risk PC or higher based on National Comprehensive Cancer Network guidelines.

RESULTS

Adding MRI-targeted biopsies to systematic biopsies increased sensitivity of GS ≥3 + 4 PC compared with systematic biopsies alone (relative sensitivity [RS] = 1.52, 95% confidence interval [CI] = 1.28 to 1.85). Performing biopsies in only MRI positive increased sensitivity of GS ≥3 + 4 PC (RS = 1.30, 95% CI = 1.04 to 1.67) and reduced number of biopsy procedures by 49.3% while missing 7.2% GS ≥3 + 4 PC and 1.4% csPCa. Excluding men with negative Stockholm3 test reduced the number of MRI investigations at follow-up by 22.5% and biopsies by 56.8% while missing 6.9% GS ≥3 + 4 PC and 1.3% csPCa.

CONCLUSION

Including MRI and targeted/systematic biopsies in the follow-up for men on AS increased sensitivity of PC reclassification. Incorporation of risk prediction models including biomarkers may reduce the need for MRI use in men with low-risk PC.

Multiparametric Magnetic Resonance Imaging Alone is Insufficient to Detect Grade Reclassification in Active Surveillance for Prostate Cancer

Multiparametric magnetic resonance imaging (mpMRI) has improved the detection of clinically significant prostate cancer. It remains unclear, however, whether mpMRI can safely replace confirmatory or surveillance biopsies in men with low-risk disease managed with active surveillance (AS). Overall, 166 men were upgraded at a median of 29 mo (interquartile range 13-54). The overall negative predictive value (NPV) of mpMRI was 79.5% and ranged from 74.4% to 84.6% for all AS biopsies up to the fourth surveillance biopsy. In men with prostate-specific antigen density ≥0.15 ng/ml/cm³, the overall NPV of mpMRI was 65.5% and ranged from 57.1% to 73.3% across serial mpMRI scans. These findings support the hypothesis that mpMRI is helpful but insufficient to rule out pathological reclassification, especially at confirmatory biopsy or in the presence of other risk factors. PATIENT SUMMARY: Multiparametric magnetic resonance imaging (mpMRI) alone misses a considerable percentage of clinically significant prostate cancers (Gleason grade group ≥2) in men on active surveillance for low-risk prostate cancer. We conclude that mpMRI alone cannot safely replace surveillance prostate biopsies, particularly at confirmatory biopsy or in the presence of other risk factors.

Role of multiparametric prostate MRI in the management of prostate cancer

INTRODUCTION

Prostate cancer has traditionally been diagnosed by an elevation in PSA or abnormal exam leading to a systematic transrectal ultrasound (TRUS)-guided biopsy. This diagnostic pathway underdiagnoses clinically significant disease while over diagnosing clinically insignificant disease. In this review, we aim to provide an overview of the recent literature regarding the role of multiparametric MRI (mpMRI) in the management of prostate cancer.

MATERIALS AND METHODS

A thorough literature review was performed using PubMed to identify articles discussing use of mpMRI of the prostate in management of prostate cancer.

CONCLUSION

The incorporation of mpMRI of the prostate addresses the shortcomings of the prostate biopsy while providing several other advantages. mpMRI allows some men to avoid an immediate biopsy and permits visualization of areas likely to harbor clinically significant cancer prior to biopsy to facilitate use of MR-targeted prostate biopsies. This allows for reduction in diagnosis of clinically insignificant disease as well as improved detection and better characterization of higher risk cancers, as well as the improved selection of patients for active surveillance. In addition, mpMRI can be used for selection and monitoring of patients for active surveillance and treatment planning during surgery and focal therapy.