The PICTURE study: diagnostic accuracy of multiparametric MRI in men requiring a repeat prostate biopsy

Assessment of diagnostic value of unilateral systematic biopsy combined with targeted biopsy in detecting clinically significant prostate cancer

Objectives

This retrospective study assessed the diagnostic accuracy of targeted biopsy (TB) and unilateral systematic biopsy in detecting clinically significant prostate cancer (csPCa) in 222 men with single magnetic resonance imaging (MRI) lesions (Prostate Imaging Reporting and Data System [PI-RADS] ≥ 3).

Methods

Patients underwent multiparametric MRI and MRI/ultrasound fusion TB and 12-needle standard biopsy (SB) from September 2016 to June 2021. The study compared the diagnostic performance of TB + iSB (ipsilateral), TB + contralateral system biopsy (cSB) (contralateral), and TB alone for csPCa using the χ 2 test and analysis of variance.

Results

Among 126 patients with csPCa (ISUP ≥ 2), detection rates for TB + iSB, TB + cSB, and TB were 100, 98.90, and 100% for lesions, respectively. TB + iSB showed the highest sensitivity and negative predictive value. No significant differences in accuracy were found between TB + iSB and the gold standard for type 3 lesions (P = 1). For types 4-5, detection accuracy was comparable across methods (P = 0.314, P = 0.314, P = 0.153). TB had the highest positive needle count rate, with TB + iSB being second for type 3 lesions (4.08% vs 6.57%, P = 0.127).

Conclusion

TB + iSB improved csPCa detection rates and reduced biopsy numbers, making it a viable alternative to TB + SB for single MRI lesions.

Comparison of the incidence of clinically significant prostate cancer in patients with isolated peripheral versus transitional zone PIRADS 3 lesions

INTRODUCTION

We sought to investigate the association between isolated PIRADS 3 lesions of the transitional zone (TZ) versus the peripheral zone (PZ) and the incidence of clinically significant prostate cancer (csPCa) on systematic and targeted prostate biopsy (SB, TB).

METHODS

We retrospectively reviewed our tertiary institutional database of patients who underwent mpMRI-fusion followed by TB + SB between 2016 and 2021. We compared the incidence of csPCa (Gleason Grade Group ⩾ 2) in patients with solitary TZ-only PIRADS 3 and PZ-only PIRADS 3 on SB and TB. We excluded patients with (1)known PCa, (2)PIRADS 4-5 and/or (3)lesions in both TZ and PZ. T-tests, Chi-square tests, were conducted to compare between the groups.

RESULTS

Of 1913 patients, we identified 110 with PZ-only and 38 with TZ-only PIRADS 3 lesions. 73 patients in PZ-only and 19 in TZ-only met inclusion criteria. No statistically significant differences were observed between PZ and TZ groups in terms of age, median prostate-specific antigen (PSA), prostate volume, median PSA-density, or median number of targeted cores obtained, all with p > 0.05.On SB, the incidence of csPCA was higher in patients with PZ rather than TZ PIRADS-3 lesions (10/73 vs 1/19, p = 0.28). Similarly, csPCA was more common in TB of PZ versus TZ PIRADS 3 lesions (7/73 vs 0/19, p = 0.33). Based on these results, the positive predictive values of PIRADS3 as a marker of csPCA were 5.3% and 0% for TZ lesions on SB versus TB, respectively, compared to 17.7% and 9.6% in the PZ.

CONCLUSIONS

PIRADS 3 lesions are rarely associated with csPCA on SB and TB, particularly when located in the TZ, which is an important factor to consider when deciding on a biopsy in patients with isolated TZ lesions.

A contemporary review: mpMRI in prostate cancer screening and diagnosis

Prostate cancer (PCa) screening has evolved beyond PSA and digital rectal exam to include multiparametric prostate MRI (mpMRI). Incorporating this advanced imaging tool has further limited the well-established problem of overdiagnosis, aiding in the identification of higher grade, clinically significant cancers. For this reason, mpMRI has become an important part of the diagnostic pathway and is recommended across guidelines in biopsy naïve patients or for patients with prior negative biopsy. This contemporary review evaluates the most recent literature on the role of mpMRI in the screening and diagnosis of prostate cancer. Barriers to utilization of mpMRI still exist including variable access, high cost, and requisite expertise, encouraging evaluation of novel techniques such as biparametric MRI. Future screening and diagnostic practice patterns will undoubtedly evolve as our understanding of novel biomarkers and artificial intelligence improves.

Prostate cancer segmentation from MRI by a multistream fusion encoder

BACKGROUND

Targeted prostate biopsy guided by multiparametric magnetic resonance imaging (mpMRI) detects more clinically significant lesions than conventional systemic biopsy. Lesion segmentation is required for planning MRI-targeted biopsies. The requirement for integrating image features available in T2-weighted and diffusion-weighted images poses a challenge in prostate lesion segmentation from mpMRI.

PURPOSE

A flexible and efficient multistream fusion encoder is proposed in this work to facilitate the multiscale fusion of features from multiple imaging streams. A patch-based loss function is introduced to improve the accuracy in segmenting small lesions.

METHODS

The proposed multistream encoder fuses features extracted in the three imaging streams at each layer of the network, thereby allowing improved feature maps to propagate downstream and benefit segmentation performance. The fusion is achieved through a spatial attention map generated by optimally weighting the contribution of the convolution outputs from each stream. This design provides flexibility for the network to highlight image modalities according to their relative influence on the segmentation performance. The encoder also performs multiscale integration by highlighting the input feature maps (low-level features) with the spatial attention maps generated from convolution outputs (high-level features). The Dice similarity coefficient (DSC), serving as a cost function, is less sensitive to incorrect segmentation for small lesions. We address this issue by introducing a patch-based loss function that provides an average of the DSCs obtained from local image patches. This local average DSC is equally sensitive to large and small lesions, as the patch-based DSCs associated with small and large lesions have equal weights in this average DSC.

RESULTS

The framework was evaluated in 931 sets of images acquired in several clinical studies at two centers in Hong Kong and the United Kingdom. In particular, the training, validation, and test sets contain 615, 144, and 172 sets of images, respectively. The proposed framework outperformed single-stream networks and three recently proposed multistream networks, attaining F1 scores of 82.2 and 87.6% in the lesion and patient levels, respectively. The average inference time for an axial image was 11.8 ms.

CONCLUSION

The accuracy and efficiency afforded by the proposed framework would accelerate the MRI interpretation workflow of MRI-targeted biopsy and focal therapies.

Prostate MRI and PSMA-PET in the Primary Diagnosis of Prostate Cancer

Over the last years, prostate magnetic resonance imaging (MRI) has gained a key role in the primary diagnosis of clinically significant prostate cancer (csPCa). While a negative MRI can avoid unnecessary prostate biopsies and the overdiagnosis of indolent cancers, a positive examination triggers biopsy samples targeted to suspicious imaging findings, thus increasing the diagnosis of csPCa with a sensitivity and negative predictive value of around 90%. The limitations of MRI, including suboptimal positive predictive values, are fueling debate on how to stratify biopsy decisions and management based on patient risk and how to correctly estimate it with clinical and/or imaging findings. In this setting, "next-generation imaging" imaging based on radiolabeled Prostate-Specific Membrane Antigen (PSMA)-Positron Emission Tomography (PET) is expanding its indications both in the setting of primary staging (intermediate-to-high risk patients) and primary diagnosis (e.g., increasing the sensitivity of MRI or acting as a problem-solving tool for indeterminate MRI cases). This review summarizes the current main evidence on the role of prostate MRI and PSMA-PET as tools for the primary diagnosis of csPCa, and the different possible interaction pathways in this setting.

Standardized prostate cancer incidence and mortality rates following initial non-malignant biopsy result

OBJECTIVES

To compare the incidence of subsequent prostate cancer diagnosis and death following an initial non-malignant systematic transrectal ultrasonography (TRUS) biopsy with that in an age- and calendar-year matched population over a 20-year period.

SUBJECTS AND METHODS

This population-based analysis compared a cohort of all men with initial non-malignant TRUS biopsy in Denmark between 1995 and 2016 (N = 37 231) with the Danish population matched by age and calendar year, obtained from the NORDCAN 9.1 database. Age- and calendar year-corrected standardized prostate cancer incidence (SIR) and prostate cancer-specific mortality ratios (SMRs) were calculated and heterogeneity among age groups was assessed with the Cochran's Q test.

RESULTS

The median time to censoring was 11 years, and 4434 men were followed for more than 15 years. The corrected SIR was 5.2 (95% confidence interval [CI] 5.1-5.4) and the corrected SMR was 0.74 (95% CI 0.67-0.81). Estimates differed among age groups (P < 0.001 for both), with a higher SIR and SMR among younger men.

CONCLUSION

Men with non-malignant TRUS biopsy have a much higher incidence of prostate cancer but a risk of prostate cancer death below the population average. This underlines that the oncological risk of cancers missed in the initial TRUS biopsy is low. Accordingly, attempts to increase the sensitivity of initial biopsy are unjustified. Moreover, current follow-up after non-malignant biopsy is likely to be overaggressive, particularly in men over the age of 60 years.

PI-RADS 3 score: A retrospective experience of clinically significant prostate cancer detection

Rationale and objectives

The study aims to propose an optimal workflow in patients with a PI-RADS 3 (PR-3) assessment category (AC) through determining the timing and type of pathology interrogation used for the detection of clinically significant prostate cancer (csPCa) in these men based upon a 5-year retrospective review in a large academic medical center.

Materials and methods

This United States Health Insurance Probability and Accountability Act (HIPAA)-compliant, institutional review board-approved retrospective study included men without prior csPCa diagnosis who received PR-3 AC on magnetic resonance (MR) imaging (MRI). Subsequent incidence and time to csPCa diagnosis and number/type of prostate interventions was recorded. Categorical data were compared using Fisher's exact test and continuous data using ANOVA omnibus F-test.

Results

Our cohort of 3238 men identified 332 who received PR-3 as their highest AC on MRI, 240 (72.3%) of whom had pathology follow-up within 5 years. csPCa was detected in 76/240 (32%) and non-csPCa in 109/240 (45%) within 9.0 ± 10.6 months. Using a non-targeted trans-rectal ultrasound biopsy as the initial approach (n = 55), another diagnostic procedure was required to diagnose csPCa in 42/55 (76.4%) of men, compared with 3/21(14.3%) men with an initial MR targeted-biopsy approach (n = 21); (p < 0.0001). Those with csPCa had higher median serum prostate-specific antigen (PSA) and PSA density, and lower median prostate volume (p < 0.003) compared with non-csPCa/no PCa.

Conclusion

Most patients with PR-3 AC underwent prostate pathology exams within 5 years, 32% of whom were found to have csPCa within 1 year of MRI, most often with a higher PSA density and a prior non-csPCa diagnosis. Addition of a targeted biopsy approach initially reduced the need for a second biopsy to reach a for csPCa diagnosis. Thus, a combination of systematic and targeted biopsy is advised in men with PR-3 and a co-existing abnormal PSA and PSA density.

Single-center, prospective phase 2 trial of high-intensity focused ultrasound (HIFU) in patients with unilateral localized prostate cancer: good functional results but oncologically not as safe as expected

PURPOSE

Focal therapy (FT) for localized prostate cancer (PCa) is only recommended within the context of clinical trials by international guidelines. We aimed to investigate oncological follow-up and safety data of focal high-intensity focused ultrasound (HIFU) treatment.

METHODS

We conducted a single-center prospective study of 29 patients with PCa treated with (focal) HIFU between 2016 and 2021. Inclusion criteria were unilateral PCa detected by mpMRI-US-fusion prostate biopsy and maximum prostate specific antigen (PSA) of 15 ng/ml. Follow-up included mpMRI-US fusion-re-biopsies 12 and 24 months after HIFU. No re-treatment of HIFU was allowed. The primary endpoint was failure-free survival (FFS), defined as freedom from intervention due to cancer progression.

RESULTS

Median follow-up of all patients was 23 months, median age was 67 years and median preoperative PSA was 6.8 ng/ml. One year after HIFU treatment PCa was still detected in 13/ 29 patients histologically (44.8%). Two years after HIFU another 7/29 patients (24.1%) were diagnosed with PCa. Until now, PCa recurrence was detected in 11/29 patients (37.93%) which represents an FFS rate of 62%.One patient developed local metastatic disease 2 years after focal HIFU. Adverse events (AE) were low with 70% of patients remaining with sufficient erectile function for intercourse and 97% reporting full maintenance of urinary continence.

CONCLUSION

HIFU treatment in carefully selected patients is feasible. However, HIFU was oncologically not as safe as expected because of progression rates of 37.93% and risk of progression towards metastatic disease. Thus, we stopped usage of HIFU in our department.

Regional Histopathology and Prostate MRI Positivity: A Secondary Analysis of the PROMIS Trial

Background The effects of regional histopathologic changes on prostate MRI scans have not been accurately quantified in men with an elevated prostate-specific antigen (PSA) level and no previous biopsy. Purpose To assess how Gleason grade, maximum cancer core length (MCCL), inflammation, prostatic intraepithelial neoplasia (PIN), or atypical small acinar proliferation within a Barzell zone affects the odds of MRI visibility. Materials and Methods In this secondary analysis of the Prostate MRI Imaging Study (PROMIS; May 2012 to November 2015), consecutive participants who underwent multiparametric MRI followed by a combined biopsy, including 5-mm transperineal mapping (TPM), were evaluated. TPM pathologic findings were reported at the whole-prostate level and for each of 20 Barzell zones per prostate. An expert panel blinded to the pathologic findings reviewed MRI scans and declared which Barzell areas spanned Likert score 3-5 lesions. The relationship of Gleason grade and MCCL to zonal MRI outcome (visible vs nonvisible) was assessed using generalized linear mixed-effects models with random intercepts for individual participants. Inflammation, PIN, and atypical small acinar proliferation were similarly assessed in men who had negative TPM results. Results Overall, 161 men (median age, 62 years [IQR, 11 years]) were evaluated and 3179 Barzell zones were assigned MRI status. Compared with benign areas, the odds of MRI visibility were higher when a zone contained cancer with a Gleason score of 3+4 (odds ratio [OR], 3.1; 95% CI: 1.9, 4.9; P < .001) or Gleason score greater than or equal to 4+3 (OR, 8.7; 95% CI: 4.5, 17.0; P < .001). MCCL also determined visibility (OR, 1.24 per millimeter increase; 95% CI: 1.15, 1.33; P < .001), but odds were lower with each prostate volume doubling (OR, 0.7; 95% CI: 0.5, 0.9). In men who were TPM-negative, the presence of PIN increased the odds of zonal visibility (OR, 3.7; 95% CI: 1.5, 9.1; P = .004). Conclusion An incremental relationship between cancer burden and prostate MRI visibility was observed. Prostatic intraepithelial neoplasia contributed to false-positive MRI findings. ClinicalTrials.gov registration no. NCT01292291 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Harmath in this issue.

The Application of Biopsy Density in Transperineal Templated-Guided Biopsy Patients With PI-RADS<3

Background

In patients with multiparameter magnetic resonance imaging (mpMRI) low-possibility but highly clinical suspicion of prostate cancer, the biopsy core is unclear. Our study aims to introduce the biopsy density (BD; the ratio of biopsy cores to prostate volume) and investigates the BD-predictive value of prostate cancer and clinically significant prostate cancer (csPCa) in PI-RADS<3 patients.

Methods

Patients underwent transperineal template–guided prostate biopsy from 2012 to 2022. The inclusion criteria were PI-RADS<3 with a positive digital rectal examination or persistent PSA abnormalities. BD was defined as the ratio of the biopsy core to the prostate volume. Clinical data were collected, and we grouped the patients according to pathology results. Kruskal–Wallis test and chi-square test were used in measurement and enumeration data, respectively. Logistics regression was used to choose the factor associated with positive biospy and csPCa. The receiver operating characteristic (ROC) curve was used to evaluate the ability to predict csPCa.

Results

A total of 115 patients were included in our study. Biopsy was positive in 14 of 115 and the International Society of Urological Pathology grade groups 2–5 were in 7 of all the PCa patients. The BD was 0.38 (0.24-0.63) needles per milliliter. Binary logistics analysis suggested that PSAD and BD were correlated with positive biopsy. Meanwhile, BD and PSAD were associated with csPCa. The ROC curve illustrated that BD was a good parameter to predict csPCa (AUC=0.80, 95% CI: 0.69-0.91, p<0.05). The biopsy density combined with PSAD increased the prediction of csPCa (AUC=0.90, 95% CI: 0.85-0.97, p<0.05). The cut-off value of the BD was 0.42 according to the Youden index.

Conclusion

In PI-RADS<3 patients, BD and PSAD are related to csPCa. A biopsy density of more than 0.42 needles per millimeter can increase the csPCa detection rate, which should be considered as an alternative biopsy method when we perform prostate biopsy in patients with PI-RADS<3.

Magnetic Resonance Imaging and Targeted Biopsies Compared to Transperineal Mapping Biopsies Before Focal Ablation in Localised and Metastatic Recurrent Prostate Cancer After Radiotherapy

BACKGROUND

Recurrent prostate cancer after radiotherapy occurs in one in five patients. The efficacy of prostate magnetic resonance imaging (MRI) in recurrent cancer has not been established. Furthermore, high-quality data on new minimally invasive salvage focal ablative treatments are needed.

OBJECTIVE

To evaluate the role of prostate MRI in detection of prostate cancer recurring after radiotherapy and the role of salvage focal ablation in treating recurrent disease.

DESIGN, SETTING, AND PARTICIPANTS

The FORECAST trial was both a paired-cohort diagnostic study evaluating prostate multiparametric MRI (mpMRI) and MRI-targeted biopsies in the detection of recurrent cancer and a cohort study evaluating focal ablation at six UK centres. A total of 181 patients were recruited, with 155 included in the MRI analysis and 93 in the focal ablation analysis.

INTERVENTION

Patients underwent choline positron emission tomography/computed tomography and a bone scan, followed by prostate mpMRI and MRI-targeted and transperineal template-mapping (TTPM) biopsies. MRI was reported blind to other tests. Those eligible underwent subsequent focal ablation. An amendment in December 2014 permitted focal ablation in patients with metastases.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Primary outcomes were the sensitivity of MRI and MRI-targeted biopsies for cancer detection, and urinary incontinence after focal ablation. A key secondary outcome was progression-free survival (PFS).

RESULTS AND LIMITATIONS

Staging whole-body imaging revealed localised cancer in 128 patients (71%), with involvement of pelvic nodes only in 13 (7%) and metastases in 38 (21%). The sensitivity of MRI-targeted biopsy was 92% (95% confidence interval [CI] 83-97%). The specificity and positive and negative predictive values were 75% (95% CI 45-92%), 94% (95% CI 86-98%), and 65% (95% CI 38-86%), respectively. Four cancer (6%) were missed by TTPM biopsy and six (8%) were missed by MRI-targeted biopsy. The overall MRI sensitivity for detection of any cancer was 94% (95% CI 88-98%). The specificity and positive and negative predictive values were 18% (95% CI 7-35%), 80% (95% CI 73-87%), and 46% (95% CI 19-75%), respectively. Among 93 patients undergoing focal ablation, urinary incontinence occurred in 15 (16%) and five (5%) had a grade ≥3 adverse event, with no rectal injuries. Median follow-up was 27 mo (interquartile range 18-36); overall PFS was 66% (interquartile range 54-75%) at 24 mo.

CONCLUSIONS

Patients should undergo prostate MRI with both systematic and targeted biopsies to optimise cancer detection. Focal ablation for areas of intraprostatic recurrence preserves continence in the majority, with good early cancer control.

PATIENT SUMMARY

We investigated the role of magnetic resonance imaging (MRI) scans of the prostate and MRI-targeted biopsies in outcomes after cancer-targeted high-intensity ultrasound or cryotherapy in patients with recurrent cancer after radiotherapy. Our findings show that these patients should undergo prostate MRI with both systematic and targeted biopsies and then ablative treatment focused on areas of recurrent cancer to preserve their quality of life. This trial is registered at ClinicalTrials.gov as NCT01883128.

Evidence-based guideline recommendations on multiparametric magnetic resonance imaging in the diagnosis of clinically significant prostate cancer: A Cancer Care Ontario updated clinical practice guideline

INTRODUCTION

This clinical practice guideline is based on a systematic review to assess the use of multiparametric magnetic resonance imaging (mpMRI) in the diagnosis of clinically significant prostate cancer (csPCa) for biopsy-naive men and men with a prior negative transrectal ultrasound-guided systematic biopsy (TRUS-SB) at elevated risk.

METHODS

The methods of the clinical practice guideline included searches to September of 2020 of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. Internal and external reviews were conducted.

RESULTS

The recommendations are:Recommendation 1: For biopsy-naive patients at elevated risk of csPCa, mpMRI is recommended prior to biopsy in patients who are candidates for curative management with suspected clinically localized prostate cancer.- If the mpMRI is positive, mpMRI-targeted biopsy (TB) and TRUS-SB should be performed together to maximize detection of csPCa.- If the mpMRI is negative, consider forgoing any biopsy after discussion of the risks and benefits with the patient as part of shared decision-making and ongoing followup.Recommendation 2: In patients who had a prior negative TRUS-SB and demonstrate a high risk of having csPCa in whom curative management is being considered:- mpMRI should be performed.- If the mpMRI is positive, targeted biopsy should be performed. Concomitant TRUS-SB can be considered depending on the patient's risk profile and time since prior TRUS-SB biopsy.- If the mpMRI is negative, consider forgoing a TRUS-SB only after discussion of the risks and benefits with the patient as part of shared decision-making and ongoing followup.Recommendation 3: mpMRI should be performed and interpreted in compliance with the current Prostate Imaging Reporting & Data System (PI-RADS) guidelines.

Diagnostic Accuracy of Abbreviated Bi-Parametric MRI (a-bpMRI) for Prostate Cancer Detection and Screening: A Multi-Reader Study

(1) Background: There is currently limited evidence on the diagnostic accuracy of abbreviated biparametric MRI (a-bpMRI) protocols for prostate cancer (PCa) detection and screening. In the present study, we aim to investigate the performance of a-bpMRI among multiple readers and its potential application to an imaging-based screening setting. (2) Methods: A total of 151 men who underwent 3T multiparametric MRI (mpMRI) of the prostate and transperineal template prostate mapping biopsies were retrospectively selected. Corresponding bpMRI (multiplanar T2WI, DWI, ADC maps) and a-bpMRI (axial T2WI and b 2000 s/mm² DWI only) dataset were derived from mpMRI. Three experienced radiologists scored a-bpMRI, standard biparametric MRI (bpMRI) and mpMRI in separate sessions. Diagnostic accuracy and interreader agreement of a-bpMRI was tested for different positivity thresholds and compared to bpMRI and mpMRI. Predictive values of a-bpMRI were computed for lower levels of PCa prevalence to simulate a screening setting. The primary definition of clinically significant PCa (csPCa) was Gleason ≥ 4 + 3, or cancer core length ≥ 6 mm. (3) Results: The median age was 62 years, the median PSA was 6.8 ng/mL, and the csPCa prevalence was 40%. Using a cut off of MRI score ≥ 3, the sensitivity and specificity of a-bpMRI were 92% and 48%, respectively. There was no significant difference in sensitivity compared to bpMRI and mpMRI. Interreader agreement of a-bpMRI was moderate (AC1 0.58). For a low prevalence of csPCa (e.g., <10%), higher cut offs (MRI score ≥ 4) yield a more favourable balance between the predictive values and positivity rate of MRI. (4) Conclusion: Abbreviated bpMRI protocols could match the diagnostic accuracy of bpMRI and mpMRI for the detection of csPCa. If a-bpMRI is used in low-prevalence settings, higher cut-offs for MRI positivity should be prioritised.

Relationship of prostate cancer topography and tumour conspicuity on multiparametric magnetic resonance imaging: a protocol for a systematic review and meta-analysis

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI) has improved the triage of men with suspected prostate cancer, through precision prebiopsy identification of clinically significant disease. While multiple important characteristics, including tumour grade and size have been shown to affect conspicuity on mpMRI, tumour location and association with mpMRI visibility is an underexplored facet of this field. Therefore, the objective of this systematic review and meta-analysis is to collate the extant evidence comparing MRI performance between different locations within the prostate in men with existing or suspected prostate cancer. This review will help clarify mechanisms that underpin whether a tumour is visible, and the prognostic implications of our findings.

METHODS AND ANALYSIS

The databases MEDLINE, PubMed, Embase and Cochrane will be systematically searched for relevant studies. Eligible studies will be full-text English-language articles that examine the effect of zonal location on mpMRI conspicuity. Two reviewers will perform study selection, data extraction and quality assessment. A third reviewer will be involved if consensus is not achieved. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will inform the methodology and reporting of the review. Study bias will be assessed using a modified Newcastle-Ottawa scale. A thematic approach will be used to synthesise key location-based factors associated with mpMRI conspicuity. A meta-analysis will be conducted to form a pooled value of the sensitivity and specificity of mpMRI at different tumour locations.

ETHICS AND DISSEMINATION

Ethical approval is not required as it is a protocol for a systematic review. Findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42021228087.

Negative multiparametric magnetic resonance imaging for prostate cancer: further outcome and consequences

PURPOSE

EAU guidelines recommend multiparametric MRI of the prostate (mpMRI) prior to biopsy to increase accuracy and reduce biopsies. Whether biopsy can be avoided in case of negative mpMRI remains unclear. Aim of this study is to evaluate predictors of overall prostate cancer (PCa) in negative mpMRI.

METHODS

A total of 216 patients from 2018 to 2020 with suspicion of PCa and negative mpMRI (PI-RADS ≤ 2) were interviewed by telephone about outcome and further follow-up. Clinically significant PCa (csPCa) was defined as ISUP ≥ 2. Patients with vs. without biopsy and with vs. without PCa were compared. Univariate and multivariate analyses were performed to evaluate predictors of PCa occurrence in patients with negative mpMRI.

RESULTS

15.7% and 5.1% of patients with PI-RADS ≤ 2 on mpMRI showed PCa and csPCa, respectively. PCa patients had higher PSAD (0.14 vs. 0.09 ng/ml²; p = 0.001) and lower prostate volume (50.5 vs. 74.0 ml; p = 0.003). Patients without biopsy (25%) after MRI were older (69 vs. 65.5 years; p = 0.027), showed lower PSA (5.7 vs. 6.73 ng/ml; p = 0.033) and lower PSA density (0.09 vs. 0.1 ng/ml²; p = 0.027). Multivariate analysis revealed age (OR 1.09 [1.02-1.16]; p = 0.011), prostate volume (OR 0.982 [0.065; 0.997]; p = 0.027), total PSA level (OR 1.22 [1.01-1.47], p = 0.033), free PSA (OR 0.431 [0.177; 0.927]; p = 0.049) and no PI-RADS lesion vs PI-RADS 1-2 lesion (OR 0.38 [0.15-0.91], p = 0.032.) as predictive factors for the endpoint presence of PCa.

CONCLUSIONS

Biopsy for selected patient groups (higher age, prostate volume and free PSA as well as lower PSA-Density) with negative mpMRI can be avoided, if sufficient follow-up care is guaranteed. Detailed counseling regarding residual risk for undetected prostate cancer should be mandatory.

AutoProstate: Towards Automated Reporting of Prostate MRI for Prostate Cancer Assessment Using Deep Learning

Multiparametric magnetic resonance imaging (mpMRI) of the prostate is used by radiologists to identify, score, and stage abnormalities that may correspond to clinically significant prostate cancer (CSPCa). Automatic assessment of prostate mpMRI using artificial intelligence algorithms may facilitate a reduction in missed cancers and unnecessary biopsies, an increase in inter-observer agreement between radiologists, and an improvement in reporting quality. In this work, we introduce AutoProstate, a deep learning-powered framework for automatic MRI-based prostate cancer assessment. AutoProstate comprises of three modules: Zone-Segmenter, CSPCa-Segmenter, and Report-Generator. Zone-Segmenter segments the prostatic zones on T2-weighted imaging, CSPCa-Segmenter detects and segments CSPCa lesions using biparametric MRI, and Report-Generator generates an automatic web-based report containing four sections: Patient Details, Prostate Size and PSA Density, Clinically Significant Lesion Candidates, and Findings Summary. In our experiment, AutoProstate was trained using the publicly available PROSTATEx dataset, and externally validated using the PICTURE dataset. Moreover, the performance of AutoProstate was compared to the performance of an experienced radiologist who prospectively read PICTURE dataset cases. In comparison to the radiologist, AutoProstate showed statistically significant improvements in prostate volume and prostate-specific antigen density estimation. Furthermore, AutoProstate matched the CSPCa lesion detection sensitivity of the radiologist, which is paramount, but produced more false positive detections.

Finding safe dose-volume constraints for re-irradiation with SBRT of patients with prostate cancer relapse: The IEO experience

AIM

The primary aim of this study is to provide preliminary indications for safe constraints of rectum and bladder in patients re-irradiated with stereotactic body RT (SBRT).

METHODS

Data from patients treated for prostate cancer (PCa) and intraprostatic relapse, from 1998 to 2016, were retrospectively collected. First RT course was delivered with 3D conformal RT techniques, SBRT or volumetric modulated arc therapy (VMAT). All patients underwent re-irradiation with SBRT with heavy hypofractionated schedules. Cumulative dose-volume values to organs at risk (OARs) were computed and possible correlation with developed toxicities was investigated.

RESULTS

Twenty-six patients were included. Median age at re-irradiation was 75 years, mean interval between the two RT courses was 5.6 years and the median follow-up was 47.7 months (13.4-114.3 months). After re-irradiation, acute and late G ≥ 2 GU toxicity events were reported in 3 (12%) and 10 (38%) patients, respectively, while late G ≥ 2 GI events were reported in 4 (15%) patients. No acute G ≥ 2 GI side effects were registered. Patients receiving an equivalent uniform dose of the two RT treatments < 131 Gy appeared to be at higher risk of progression (4-yr b-PFS: 19% vs 33%, p = 0.145). Cumulative re-irradiation constraints that appear to be safe are D_30% < 57.9 Gy for bladder and D_30% < 66.0 Gy, D_60% < 38.0 Gy and V_{122.1 Gy} < 5% for rectum.

CONCLUSION

Preliminary re-irradiation constraints for bladder and rectum have been reported. Our preliminary investigation may serve to clear some grey areas of PCa re-irradiation.

A multicenter retrospective study on evaluation of predicative factors for positive biopsy of prostate cancer in real-world setting

OBJECTIVE

This study aimed to evaluate the predictors for positive biopsy in prostate cancer (PCa) patients and develop a risk-stratification score model for positive biopsy rate in patients with prostate specific antigen (PSA) in the gray zone.

METHODS

In this retrospective, multicenter, real-world study, Chinese patients receiving prostate biopsy for the first time were included. The study evaluated the positive biopsy rate, predictors for positive biopsy and a risk prediction model for PSA 4-10 ng/mL PCa was developed. The univariate and multivariate logistic regression analyses were used to identify the risk factors.

RESULTS

A total of 2426 patients were included in the study. The biopsy positive rate was 47.57%, 25.77%, and 60.57% among overall patients, total PSA (t-PSA) 4-10 ng/mL patients, and PSA > 10 ng/mL patients respectively. Elderly age 60-74, ≥75, multi parametric magnetic resonance imaging (MP-MRI), pre-operative PSA > 10 and PSA density (PSAD) significantly increased the positive rate in overall population, and elderly age, MP-MRI, positive digital rectal examination and f-PSA were significant predictors for positive biopsy in PSA 4-10 ng/mL population. A risk prediction model for positive biopsy rate in patients with PSA in the gray zone was developed. Area under curve (AUC) was associated with low accuracy for all the variables used such as tPSA (0.53), PSAD (0.57), frequency of puncture (0.53) and MP-MRI (0.64) in prediction of biopsy positive rate.

CONCLUSION

Our study evaluated the significant predicative factors for positive biopsy and the PCa risk prediction model developed might help Clinicians to avoid unnecessary biopsy in patients with PSA in gray zone.

Multiparametric Magnetic Resonance Imaging in the Diagnosis of Clinically Significant Prostate Cancer: an Updated Systematic Review

There has been growing utilisation of multiparametric magnetic resonance imaging (MPMRI) as a non-invasive tool to diagnose and localise clinically significant prostate cancer (CSPCa). This updated systematic review examines the use of MPMRI in patients with an elevated risk of CSPCa who have had a prior negative transrectal ultrasound systematic biopsy (TRUS-SB) and who were biopsy naïve. MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were searched for existing systematic reviews published up to September 2020. The literature search of the electronic databases combined disease-specific terms (prostate cancer, prostate carcinoma, etc.) and treatment-specific terms (magnetic resonance, etc.). Studies were included if they were randomised controlled trials (RCTs) comparing MPMRI to template transperineal mapping biopsy (TPMB) or to TRUS-SB. Thirty-six RCTs were eligible. For biopsy-naïve men, accuracy of diagnosis of CSPCa showed sensitivities from 87 to 96% and specificities ranging from 29 to 45%. Meta-analyses for CSPCa showed increased detection favouring MPMRI-targeted biopsy over TRUS-SB by 3% (95% confidence interval 0-7%, P = 0.03) and decreased detection of clinically insignificant prostate cancer (CISPCa) favouring MPMRI by 8% (95% confidence interval -11 to 5%, P < 0.00001). Accuracy of MPMRI for men with prior negative biopsy showed sensitivities of 78-100% and specificities of 30-100%. Meta-analyses comparing MPMRI to TRUS-SB showed increased detection of 5% (95% confidence interval 3-7%, P < 0.0001) with a reduction of CISPCa detection of 7% (95% confidence interval 4-9%, P < 0.00001). The growing acceptance of MPMRI utilisation internationally and the recent publication of several RCTs regarding MPMRI in reducing CISPCa detection rates, particularly in biopsy-naïve men, without loss of sensitivity for CSPCa necessitates the synthesis of updated evidence examining MPMRI in the diagnosis of CSPCa.

Which Prostate Cancers are Undetected by Multiparametric Magnetic Resonance Imaging in Men with Previous Prostate Biopsy? An Analysis from the PICTURE Study

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) has improved risk stratification for suspected prostate cancer in patients following prior biopsy. However, not all significant cancers are detected by mpMRI. The PICTURE study provides the ideal opportunity to investigate cancer undetected by mpMRI owing to the use of 5 mm transperineal template mapping (TTPM) biopsy.

OBJECTIVE

To summarise attributes of cancers systematically undetected by mpMRI in patients with prior biopsy.

DESIGN SETTING AND PARTICIPANTS

PICTURE was a paired-cohort confirmatory study in which men requiring repeat biopsy underwent mpMRI followed by TTPM biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Attributes were compared between cancers detected and undetected by mpMRI at the patient level. Four predefined histopathological thresholds were used as the target condition for TTPM biopsy. Application of prostate-specific antigen density (PSAD) was explored.

RESULTS AND LIMITATIONS

When nonsuspicious mpMRI was defined as Likert score 1-2, 2.9% of patients (3/103; 95% confidence interval [CI] 0.6-8.3%) with definition 1 disease (Gleason ≥ 4 + 3 of any length or maximum cancer core length [MCCL] ≥ 6 mm of any grade) had their cancer not detected by mpMRI. This proportion was 6.5% (11/168; 95% CI 3.3-11%) for definition 2 disease (Gleason ≥ 3 + 4 of any length or MCCL ≥ 4 mm of any grade), 4.8% (7/146; 95% CI 2.0-9.6%) for any amount of Gleason ≥ 3 + 4 cancer, and 9.3% (20/215; 95% CI 5.8-14%) for any cancer. Definition 1 cancers undetected by mpMRI had lower overall Gleason score (p = 0.02) and maximum Gleason score (p = 0.01) compared to cancers detected by mpMRI. Prostate cancers undetected by mpMRI had shorter MCCL than cancers detected by mpMRI for every cancer threshold: definition 1, 6 versus 8 mm (p = 0.02); definition 2, 5 versus 6 mm (p = 0.04); any Gleason ≥ 3 + 4, 5 versus 6 mm (p = 0.03); and any cancer, 3 versus 5 mm (p = 0.0009). A theoretical PSAD threshold of 0.15 ng/ml/ml reduced the proportion of patients with undetected disease on nonsuspicious mpMRI to 0% (0/105; 95% CI 0-3.5%) for definition 1, 0.58% (1/171; 95% CI 0.01-3.2%) for definition 2, and 0% (0/146) for any Gleason ≥ 3 + 4.

CONCLUSIONS

Few significant cancers are undetected by mpMRI in patients requiring repeat prostate biopsy. Undetected tumours are of lower overall and maximum Gleason grade and shorter cancer length compared to cancers detected by mpMRI.

PATIENT SUMMARY

In patients with a previous prostate biopsy, magnetic resonance imaging (MRI) overlooks few prostate cancers, and these tend to be smaller and less aggressive than cancer that is detected.

Focal Therapy for Prostate Cancer: Complications and Their Treatment

Focal therapy is a modern alternative to selectively treat a specific part of the prostate harboring clinically significant disease while preserving the rest of the gland. The aim of this therapeutic approach is to retain the oncological benefit of active treatment and to minimize the side-effects of common radical treatments. The oncological effectiveness of focal therapy is yet to be proven in long-term robust trials. In contrast, the toxicity profile is well-established in randomized controlled trials and multiple robust prospective cohort studies. This narrative review summarizes the relevant evidence on complications and their management after focal therapy. When compared to whole gland treatments, focal therapy provides a substantial benefit in terms of adverse events reduction and preservation of genito-urinary function. The most common complications occur in the peri-operative period. Urinary tract infection and acute urinary retention can occur in up to 17% of patients, while dysuria and haematuria are more common. Urinary incontinence following focal therapy is very rare (0-5%), and the vast majority of patients recover in few weeks. Erectile dysfunction can occur after focal therapy in 0-46%: the baseline function and the ablation template are the most important factors predicting post-operative erectile dysfunction. Focal therapy in the salvage setting after external beam radiotherapy has a significantly higher rate of complications. Up to one man in 10 will present a severe complication.

Salvage stereotactic body radiotherapy (SBRT) for intraprostatic relapse after prostate cancer radiotherapy: An ESTRO ACROP Delphi consensus

BACKGROUND AND PURPOSE

Between 30% and 47% of patients treated with definitive radiotherapy (RT) for prostate cancer are at risk of intraprostatic recurrence during follow-up. Re-irradiation with stereotactic body RT (SBRT) is emerging as a feasible and safe therapeutic option. However, no consensus or guidelines exist on this topic. The purpose of this ESTRO ACROP project is to investigate expert opinion on salvage SBRT for intraprostatic relapse after RT.

MATERIALS AND METHODS

A 40-item questionnaire on salvage SBRT was prepared by an internal committee and reviewed by a panel of leading radiation oncologists plus a urologist expert in prostate cancer. Following the procedure of a Delphi consensus, 3 rounds of questionnaires were sent to selected experts on prostate re-irradiation.

RESULTS

Among the 33 contacted experts, 18 (54.5%) agreed to participate. At the end of the final round, participants were able to find consensus on 14 out of 40 questions (35% overall) and major agreement on 13 questions (32.5% overall). Specifically, the consensus was reached regarding some selection criteria (no age limit, ECOG 0-1, satisfactory urinary flow), diagnostic procedures (exclusion of metastatic disease, SBRT target defined on the MRI) and therapeutic approach (no need for concomitant ADT, consideration of the first RT dose, validity of Phoenix criteria for salvage SBRT failure).

CONCLUSION

While awaiting the results of ongoing studies, our ESTRO ACROP Delphi consensus may serve as a practical guidance for salvage SBRT. Future research should address the existing disagreements on this promising approach.

Standardisation of prostate multiparametric MRI across a hospital network: a London experience

OBJECTIVES

National guidelines recommend prostate multiparametric (mp) MRI in men with suspected prostate cancer before biopsy. In this study, we explore prostate mpMRI protocols across 14 London hospitals and determine whether standardisation improves diagnostic quality.

METHODS

An MRI physicist facilitated mpMRI set-up across several regional hospitals, working together with experienced uroradiologists who judged diagnostic quality. Radiologists from the 14 hospitals participated in the assessment and optimisation of prostate mpMRI image quality, assessed according to both PiRADSv2 recommendations and on the ability to "rule in" and/or "rule out" prostate cancer. Image quality and sequence parameters of representative mpMRI scans were evaluated across 23 MR scanners. Optimisation visits were performed to improve image quality, and 2 radiologists scored the image quality pre- and post-optimisation.

RESULTS

20/23 mpMRI protocols, consisting of 111 sequences, were optimised by modifying their sequence parameters. Pre-optimisation, only 15% of T2W images were non-diagnostic, whereas 40% of ADC maps, 50% of high b-value DWI and 41% of DCE-MRI were considered non-diagnostic. Post-optimisation, the scores were increased with 80% of ADC maps, 74% of high b-value DWI and 88% of DCE-MRI to be partially or fully diagnostic. T2W sequences were not optimised, due to their higher baseline quality scores.

CONCLUSIONS

Targeted intervention at a regional level can improve the diagnostic quality of prostate mpMRI protocols, with implications for improving prostate cancer detection rates and targeted biopsies.

Evaluation of PSA and PSA Density in a Multiparametric Magnetic Resonance Imaging-Directed Diagnostic Pathway for Suspected Prostate Cancer: The INNOVATE Trial

Objectives: To assess the clinical outcomes of mpMRI before biopsy and evaluate the space remaining for novel biomarkers. Methods: The INNOVATE study was set up to evaluate the validity of novel fluidic biomarkers in men with suspected prostate cancer who undergo pre-biopsy mpMRI. We report the characteristics of this clinical cohort, the distribution of clinical serum biomarkers, PSA and PSA density (PSAD), and compare the mpMRI Likert scoring system to the Prostate Imaging-Reporting and Data System v2.1 (PI-RADS) in men undergoing biopsy. Results: 340 men underwent mpMRI to evaluate suspected prostate cancer. 193/340 (57%) men had subsequent MRI-targeted prostate biopsy. Clinically significant prostate cancer (csigPCa), i.e., overall Gleason ≥ 3 + 4 of any length OR maximum cancer core length (MCCL) ≥4 mm of any grade including any 3 + 3, was found in 96/195 (49%) of biopsied patients. Median PSA (and PSAD) was 4.7 (0.20), 8.0 (0.17), and 9.7 (0.31) ng/mL (ng/mL/mL) in mpMRI scored Likert 3,4,5 respectively for men with csigPCa on biopsy. The space for novel biomarkers was shown to be within the group of men with mpMRI scored Likert3 (178/340) and 4 (70/350), in whom an additional of 40% (70/178) men with mpMRI-scored Likert3, and 37% (26/70) Likert4 could have been spared biopsy. PSAD is already considered clinically in this cohort to risk stratify patients for biopsy, despite this 67% (55/82) of men with mpMRI-scored Likert3, and 55% (36/65) Likert4, who underwent prostate biopsy had a PSAD below a clinical threshold of 0.15 (or 0.12 for men aged <50 years). Different thresholds of PSA and PSAD were assessed in mpMRI-scored Likert4 to predict csigPCa on biopsy, to achieve false negative levels of ≤5% the proportion of patients whom who test as above the threshold were unsuitably high at 86 and 92% of patients for PSAD and PSA respectively. When PSA was re tested in a sub cohort of men repeated PSAD showed its poor reproducibility with 43% (41/95) of patients being reclassified. After PI-RADS rescoring of the biopsied lesions, 66% (54/82) of the Likert3 lesions received a different PI-RADS score. Conclusions: The addition of simple biochemical and radiological markers (Likert and PSAD) facilitate the streamlining of the mpMRI-diagnostic pathway for suspected prostate cancer but there remains scope for improvement, in the introduction of novel biomarkers for risk assessment in Likert3 and 4 patients, future application of novel biomarkers tested in a Likert cohort would also require re-optimization around Likert3/PI-RADS2, as well as reproducibility testing.

Comparative Effectiveness of Techniques in Targeted Prostate Biopsy

Simple Summary

Prostate cancer is one of the most common cancers in men. Traditionally, prostate cancer is diagnosed via transrectal ultrasound-guided prostate biopsy, using a systematic random template. Using multiparametric magnetic resonance imaging, lesions suspicious for prostate cancer can be identified, and subsequently targeted on biopsy, allowing for increased diagnostic accuracy. This article reviewed the current literature surrounding various types of targeted biopsy, such as transperineal biopsy, allowing for comparison not only between targeted biopsy and systematic biopsy, but also between different varieties of targeted biopsy.

Abstract

In this review, we evaluated literature regarding different modalities for multiparametric magnetic resonance imaging (mpMRI) and mpMRI-targeted biopsy (TB) for the detection of prostate cancer (PCa). We identified studies evaluating systematic biopsy (SB) and TB in the same patient, thereby allowing each patient to serve as their own control. Although the evidence supports the accuracy of TB, there is still a proportion of clinically significant PCa (csPCa) that is detected only in SB, indicating the importance of maintaining SB in the diagnostic pathway, albeit with additional cost and morbidity. There is a growing subset of data which supports the role of TB alone, which may allow for increased efficiency and decreased complications. We also compared the literature on transrectal (TR) vs. transperineal (TP) TB. Although further high-level evidence is necessary, current evidence supports similar csPCa detection rate for both approaches. We also evaluated various TB techniques such as cognitive fusion biopsy (COG-TB) and in-bore biopsy (IB-TB). COG-TB has comparable detection rates to software fusion, but is operator-dependent and may have reduced accuracy for smaller lesions. IB-TB may allow for greater precision as lesions are directly targeted; however, this is costly and time-consuming, and does not account for MRI-invisible lesions.

Assessment of magnetic resonance imaging (MRI)-fusion prostate biopsy with concurrent standard systematic ultrasound-guided biopsy among men requiring repeat biopsy

INTRODUCTION

The role of magnetic resonance imaging (MRI)-fusion biopsy (FB) remains unclear in men with prior negative prostate biopsies. This study aimed to compare the diagnostic accuracy of FB with concurrent systematic biopsy (SB) in patients requiring repeat prostate biopsies.

METHODS

Patients with previous negative prostate biopsies requiring repeat biopsies were included. Those without suspicious lesions (≥Prostate Imaging-Reporting and Data System [PI-RADS] 3) on MRI were excluded. All patients underwent FB followed by SB. The primary outcome was the sensitivity for clinically significant prostate cancer (Gleason score ≥7). The secondary objective was identification of potential predictive factors of biopsy performance.

RESULTS

A total of 53 patients were included; 41 (77%) patients were found to have clinically significant prostate cancer. FB had a higher detection rate of significant cancer compared to SB (85% vs. 76%, respectively, p=0.20) and lower diagnosis of indolent (Gleason score 3+3=6) cancer (10% vs. 27%, respectively, p=0.05). FB alone missed six (15%) clinically significant cancers, compared to 10 (24%) with SB. SB performance was significantly impaired in patients with anterior lesions and high prostate volumes (p<0.05). There was high degree of pathological discordance between the two approaches, with concordance seen in only 34% of patients.

CONCLUSIONS

In patients with prior negative biopsies and ongoing suspicion for prostate cancer, a combined approach of FB with SB is needed for optimal detection and risk classification of clinically significant disease. Anterior tumors and large prostates were significant predictors of poor SB performance and an MRI-fusion alone approach in these settings could be considered.

Magnetic Resonance Imaging Based Radiomic Models of Prostate Cancer: A Narrative Review

Simple Summary

The increasing interest in implementing artificial intelligence in radiomic models has occurred alongside advancement in the tools used for computer-aided diagnosis. Such tools typically apply both statistical and machine learning methodologies to assess the various modalities used in medical image analysis. Specific to prostate cancer, the radiomics pipeline has multiple facets that are amenable to improvement. This review discusses the steps of a magnetic resonance imaging based radiomics pipeline. Present successes, existing opportunities for refinement, and the most pertinent pending steps leading to clinical validation are highlighted.

Abstract

The management of prostate cancer (PCa) is dependent on biomarkers of biological aggression. This includes an invasive biopsy to facilitate a histopathological assessment of the tumor’s grade. This review explores the technical processes of applying magnetic resonance imaging based radiomic models to the evaluation of PCa. By exploring how a deep radiomics approach further optimizes the prediction of a PCa’s grade group, it will be clear how this integration of artificial intelligence mitigates existing major technological challenges faced by a traditional radiomic model: image acquisition, small data sets, image processing, labeling/segmentation, informative features, predicting molecular features and incorporating predictive models. Other potential impacts of artificial intelligence on the personalized treatment of PCa will also be discussed. The role of deep radiomics analysis-a deep texture analysis, which extracts features from convolutional neural networks layers, will be highlighted. Existing clinical work and upcoming clinical trials will be reviewed, directing investigators to pertinent future directions in the field. For future progress to result in clinical translation, the field will likely require multi-institutional collaboration in producing prospectively populated and expertly labeled imaging libraries.

Systematic and MRI-Cognitive Targeted Transperineal Prostate Biopsy Accuracy in Detecting Clinically Significant Prostate Cancer after Previous Negative Biopsy and Persisting Suspicion of Malignancy

Background and objectives: Overdiagnosis, overtreatment, and the need for repeated procedures caused by transrectal ultrasound guided prostate biopsies and their related complications places a heavy burden on healthcare systems. This was a prospective cohort validating study to access the clinical accuracy of systematic and MRI-cognitive targeted transperineal prostate biopsies in detecting clinically significant prostate cancer after a previous negative biopsy and persistent suspicion of malignancy. The primary goal was to assess the ability of multiparametric magnetic resonance imaging (mpMRI) to detect clinically significant prostate cancer with an additional goal to assess the diagnostic value of systematic and MRI-cognitive transperineal biopsies. Materials and Methods: In total, 200 patients were enrolled who had rising serum prostate specific antigen (PSA) levels for at least 4 months after a previous negative transrectal ultrasound (TRUS) biopsy. All eligible men underwent 1.5T prostate mpMRI, reported using the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2), followed by a 20-region transperineal prostate systematic biopsy and additional targeted biopsies. Results: Systematic 20-core transperineal prostate biopsies (TPBs) were performed for 38 (19%) patients. Systemic 20-core TPB with additional cognitive targeted biopsies were performed for 162 (81%) patients. Clinically significant prostate cancer (csPC) was detected for 31 (15.5%) patients, of which 20 (64.5%) cases of csPC were detected by systematic biopsy, eight (25.8%) cases were detected by targeted biopsy, and three (9.7%) both by systematic and targeted biopsies. Conclusions: Cognitive mpMRI guided transperineal target biopsies increase the detection rate of clinically significant prostate cancer after a previously negative biopsy. However, in a repeat prostate biopsy setting, we recommend applying a cognitive targeted biopsy with the addition of a systematic biopsy.

Role of MRI for the detection of prostate cancer

The use of multiparametric MRI has been hastened under expanding, novel indications for its use in the diagnostic and management pathway of men with prostate cancer. This has helped drive a large body of the literature describing its evolving role over the last decade. Despite this, prostate cancer remains the only solid organ malignancy routinely diagnosed with random sampling. Herein, we summarize the components of multiparametric MRI and interpretation, and present a critical review of the current literature supporting is use in prostate cancer detection, risk stratification, and management.

Arguments against using an abbreviated or biparametric prostate MRI protocol

Currently there is a lot of interest in the use of a "biparametric" or "abbreviated" prostate MR protocol, which usually refers to removal of the dynamic contrast-enhanced (DCE) MRI, in the detection of clinically significant prostate cancer. In this article we describe the benefits of DCE as part of the PI-RADS lexicon, with particular reference to its role in PI-RADS V2 category 3 peripheral zone lesions. We also discuss the benefits of triplanar T2-weighted images, and finally discuss how a mpMRI protocol is of benefit in prostate cancer staging, in evaluating for local disease recurrence, and as a biomarker for neoadjuvant therapy response.

Biparametric (bp) and multiparametric (mp) magnetic resonance imaging (MRI) approach to prostate cancer disease: a narrative review of current debate on dynamic contrast enhancement

Prostate cancer is the most common malignancy in male population. Over the last few years, magnetic resonance imaging (MRI) has proved to be a robust clinical tool for identification and staging of clinically significant prostate cancer. Though suggestions by the European Society of Urogenital Radiology to use complete multiparametric (mp) T2-weighted/diffusion weighted imaging (DWI)/dynamic contrast enhancement (DCE) acquisition for all prostate MRI examinations, the real advantage of functional DCE remains a matter of debate. Recent studies demonstrate that biparametric (bp) and mp approaches have similar accuracy, but controversial evidences remain, and the specific potential benefits of contrast medium administration are still poorly discussed in literature. The bp approach is in fact sufficient in most cases to adequately identify a negative test, or to accurately define the degree of aggressiveness of a lesion, especially if larger or with major characteristics of malignancy. This feature would give the DCE a secondary role, probably limited to a second evaluation of the lesion location, for detecting small cancer or in case of controversy. However, DCE has proved to increase the sensitivity of prostate MRI, though a less specificity. Therefore, an appropriate decision algorithm is needed to standardize the MRI approach. Aim of this review study was to provide a schematic description of bpMRI and mpMRI approaches in the study of prostatic anatomy, focusing on comparative validity and current DCE application. Additional theoretical considerations on prostate MRI are provided.

A multifaceted approach to quality in the MRI-directed biopsy pathway for prostate cancer diagnosis

KEY POINTS

• Identify, assure, and measure major sources of variability affecting the MRI-directed biopsy pathway for prostate cancer diagnosis.• Develop strategies to control and minimize variations that impair pathway effectiveness including the performance of main players and team working.• Assure end-to-end quality of the diagnostic chain with robust multidisciplinary team working.

The "Is mpMRI Enough" or IMRIE Study: A Multicentre Evaluation of Prebiopsy Multiparametric Magnetic Resonance Imaging Compared with Biopsy

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) is now recommended prebiopsy in numerous healthcare regions based on the findings of high-quality studies from expert centres. Concern remains about reproducibility of mpMRI to rule out clinically significant prostate cancer (csPCa) in real-world settings.

OBJECTIVE

To assess the diagnostic performance of mpMRI for csPCa in a real-world setting.

DESIGN, SETTING, AND PARTICIPANTS

A multicentre, retrospective cohort study, including men referred with raised prostate-specific antigen (PSA) or an abnormal digital rectal examination who had undergone mpMRI followed by transrectal or transperineal biopsy, was conducted. Patients could be biopsy naïve or have had previous negative biopsies.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary definition for csPCa was International Society of Urological Pathology (ISUP) grade group (GG) ≥2 (any Gleason ≥7); the accuracy for other definitions was also evaluated.

RESULTS AND LIMITATIONS

Across ten sites, 2642 men were included (January 2011-November 2018). Mean age and PSA were 65.3yr (standard deviation [SD] 7.8yr) and 7.5ng/ml (SD 3.3ng/ml), respectively. Of the patients, 35.9% had "negative MRI" (scores 1-2); 51.9% underwent transrectal biopsy and 48.1% had transperineal biopsy, with 43.4% diagnosed with csPCa overall. The sensitivity and negative predictive value (NPV) for ISUP GG≥2 were 87.3% and 87.5%, respectively. The NPVs were 87.4% and 88.1% for men undergoing transrectal and transperineal biopsy, respectively. Specificity and positive predictive value of MRI were 49.8% and 49.2%, respectively. The sensitivity and NPV increased to 96.6% and 90.6%, respectively, when a PSA density threshold of 0.15ng/ml/ml was used in MRI scores 1-2; these metrics increased to 97.5% and 91.2%, respectively, for PSA density 0.12ng/ml/ml. ISUP GG≥3 (Gleason ≥4+3) was found in 2.4% (15/617) of men with MRI scores 1-2. They key limitations of this study are the heterogeneity and retrospective nature of the data.

CONCLUSIONS

Multiparametric MRI when used in real-world settings is able to rule out csPCa accurately, suggesting that about one-third of men might avoid an immediate biopsy. Men should be counselled about the risk of missing some significant cancers.

PATIENT SUMMARY

Multiparametric magnetic resonance imaging (MRI) is a useful tool for ruling out prostate cancer, especially when combined with prostate-specific antigen density (PSAD). Previous results published from specialist centres can be reproduced at smaller institutions. However, patients and their clinicians must be aware that an early diagnosis of clinically significant prostate cancer could be missed in nearly 10% of patients by relying on MRI and PSAD alone.

Diagnostic accuracy of multiparametric magnetic resonance imaging combined with clinical parameters in the detection of clinically significant prostate cancer: A novel diagnostic model

OBJECTIVES

To evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging in the detection of prostate cancer, according to Prostate Imaging Reporting and Data System, and the usefulness of combining clinical parameters to improve patients' risk assessment.

METHODS

Overall, 201 patients underwent multiparametric magnetic resonance imaging investigation with a 3-T magnet and a 32-channel body coil based on triplanar high-resolution T2-weighted, diffusion-weighted and T1-weighted dynamic contrast-enhanced imaging before, during and after intravenous administration of paramagnetic contrast agent. Random transrectal ultrasound-guided biopsy was carried out for all eligible patients. If a Prostate Imaging Reporting and Data System ≥3 lesion was present, a targeted biopsy with magnetic resonance imaging-transrectal ultrasound fusion-guided system was carried out.

RESULTS

Sensitivity, specificity, positive predictive value and negative predictive value of Prostate Imaging Reporting and Data System ≥3 lesions for the detection of prostate cancer were 65.1%, 54.9%, 43.1% and 75.0% respectively, with an accuracy of 64.2% (55.1-72.7%). At uni- and multivariate analysis, age ≥70 years and prostate-specific antigen density ≥0.15 ng/mL/mL were significantly associated with prostate cancer. A new risk model named "modified Prostate Imaging Reporting and Data System" was created considering age and prostate-specific antigen density in addition to the Prostate Imaging Reporting and Data System score showing an improved correlation with prostate cancer compared with the Prostate Imaging Reporting and Data System alone (area under curve 71.4%, 95% confidence interval 62.2-80.5 vs area under curve 62.6%, 95% confidence interval 52.1-73; P ≤ 0.0001).

CONCLUSIONS

The accuracy of Prostate Imaging Reporting and Data System alone in the diagnosis of prostate cancer might be suboptimal, whereas a novel risk model based on the combination of multiparametric magnetic resonance imaging data with clinical parameters could offer higher discrimination and improve the ability of diagnosing clinically significant disease.

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.

Negative Predictive Value of Multiparametric Magnetic Resonance Imaging in the Detection of Clinically Significant Prostate Cancer in the Prostate Imaging Reporting and Data System Era: A Systematic Review and Meta-analysis

CONTEXT

Prebiopsy multiparametric magnetic resonance imaging (mpMRI) is increasingly used in prostate cancer diagnosis. The reported negative predictive value (NPV) of mpMRI is used by some clinicians to aid in decision making about whether or not to proceed to biopsy.

OBJECTIVE

We aim to perform a contemporary systematic review that reflects the latest literature on optimal mpMRI techniques and scoring systems to update the NPV of mpMRI for clinically significant prostate cancer (csPCa).

EVIDENCE ACQUISITION

We conducted a systematic literature search and included studies from 2016 to September 4, 2019, which assessed the NPV of mpMRI for csPCa, using biopsy or clinical follow-up as the reference standard. To ensure that studies included in this analysis reflect contemporary practice, we only included studies in which mpMRI findings were interpreted according to the Prostate Imaging Reporting and Data System (PIRADS) or similar Likert grading system. We define negative mpMRI as either (1) PIRADS/Likert 1-2 or (2) PIRADS/Likert 1-3; csPCa was defined as either (1) Gleason grade group ≥2 or (2) Gleason grade group ≥3. We calculated NPV separately for each combination of negative mpMRI and csPCa.

EVIDENCE SYNTHESIS

A total of 42 studies with 7321 patients met our inclusion criteria and were included for analysis. Using definition (1) for negative mpMRI and csPCa, the pooled NPV for biopsy-naïve men was 90.8% (95% confidence interval [CI] 88.1-93.1%). When defining csPCa using definition (2), the NPV for csPCa was 97.1% (95% CI 94.9-98.7%). Calculation of the pooled NPV using definition (2) for negative mpMRI and definition (1) for csPCa yielded the following: 86.8% (95% CI 80.1-92.4%). Using definition (2) for both negative mpMRI and csPCa, the pooled NPV from two studies was 96.1% (95% CI 93.4-98.2%).

CONCLUSIONS

Multiparametric MRI of the prostate is generally an accurate test for ruling out csPCa. However, we observed heterogeneity in the NPV estimates, and local institutional data should form the basis of decision making if available.

PATIENT SUMMARY

The negative predictive values should assist in decision making for clinicians considering not proceeding to biopsy in men with elevated age-specific prostate-specific antigen and multiparametric magnetic resonance imaging reported as negative (or equivocal) on Prostate Imaging Reporting and Data System/Likert scoring. Some 7-10% of men, depending on the setting, will miss a diagnosis of clinically significant cancer if they do not proceed to biopsy. Given the institutional variation in results, it is of upmost importance to base decision making on local data if available.

Real life data of MRI-targeted biopsy - experience from a single nonacademic centre using cognitive fusion and 1.5 tesla scanning

OBJECTIVES

To date, it is unknown whether systematic biopsies can be safely omitted in patients with unsuspicious MRI findings or if systematic biopsies should be required when targeting focal lesions (PI-RADS 3-5).

METHODS

A series of 366 patients (249 without a previous biopsy) were examined in a 1.5 Tesla MRI scanner. All patients were submitted to systematic biopsies (12-14 regions) with additional targeted biopsies (by cognitive fusion) of focal PI-RADS lesions (PI-RADS 3-5).

RESULTS

In our series, patients with PI-RADS 1/2 findings had rates of adenocarcinoma of any grade, >GG1 and GG4/5 of 34%, 14% and 3%, respectively. The use of MRI prior to biopsy in our series increased the detection of clinically significant prostate cancer (CSPCa) in 28% of patients with focal lesions, and focal lesions were present in 293/366 (80%) of all patients. For CSPCa (>GG1), targeted biopsies improved the diagnosis in 28% of patients, while systematic biopsies resulted in an additional 19% of cancer cases in the series.

CONCLUSION

Systematic biopsies should still be considered in patients with PI-RADS 1/2 findings. Our findings also suggest a stronger benefit of the combined strategy of targeted and systematic biopsies than the findings of previous studies concerning the detection of CSPCa in biopsy-naïve patients.

Quantifying the Effect of Location Matching on Accuracy of Multiparametric Magnetic Resonance Imaging Prior to Prostate Biopsy-A Multicentre Study

Background

Multiparametric magnetic resonance imaging (mpMRI) has shown promise to improve detection of prostate cancer over conventional methods. However, most studies do not describe whether the location of mpMRI lesions match that of cancer found at biopsy, which may lead to an overestimation of accuracy.

Objective

To quantitate the effect of mapping locations of mpMRI lesions to locations of positive biopsy cores on the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI.

Design setting and participant

We retrospectively identified patients having mpMRI of the prostate preceding prostate biopsy at three centres from 2013 to 2016. Men with targetable lesions on imaging underwent directed biopsy in addition to systematic biopsy. We correlated locations of positive mpMRI lesions with those of positive biopsy cores, defining a match when both were in the same sector of the prostate. We defined positive mpMRI as Prostate Imaging Reporting and Data System (PI-RADS) score ≥4 and significant cancer at biopsy as grade group ≥2.

Outcome measurements and statistical analysis

Sensitivity, specificity, PPV, and NPV were calculated with and without location matching.

Results and limitations

Of 446 patients, 247 (55.4%) had positive mpMRI and 232 (52.0%) had significant cancer at biopsy. Sensitivity and NPV for detecting significant cancer with location matching (both 63.4%) were decreased compared with those without location matching (77.6% and 73.9%, respectively). Of the 85 significant cancers not detected by mpMRI, most were of grade group 2 (64.7%, 55/85).

Conclusions

We report a 10-15% decrease in sensitivity and NPV when location matching was used to detect significant prostate cancer by mpMRI. False negative mpMRI remains an issue, highlighting the continued need for biopsy and for improving the standards around imaging quality and reporting.

Patient summary

The true accuracy of multiparametric magnetic resonance imaging (mpMRI) must be determined to interpret results and better counsel patients. We mapped the location of positive mpMRI lesions to where cancer was found at biopsy and found, when compared with matching to cancer anywhere in the prostate, that the accuracy of mpMRI decreased by 10-15%.

Current Status of MRI and PET in the NCCN Guidelines for Prostate Cancer

Prostate cancer (PCa) represents a significant source of morbidity and mortality for men in the United States, with approximately 1 in 9 being diagnosed with PCa in their lifetime. The role of imaging in the evaluation of men with PCa has evolved and currently plays a central role in diagnosis, treatment planning, and evaluation of recurrence. Appropriate use of multiparametric MRI (mpMRI) and MRI-guided transrectal ultrasound (MR-TRUS) biopsy increases the detection of clinically significant PCa while decreasing the detection of clinically insignificant PCa. This process may help patients with clinically insignificant PCa avoid the adverse effects of unnecessary therapy. In the setting of a known PCa, patients with low-grade disease can be observed using active surveillance, which often includes a combination of prostate-specific antigen (PSA) testing, serial mpMRI, and, if indicated, follow-up systematic and targeted TRUS-guided tissue sampling. mpMRI can provide important information in the posttreatment setting, but PET/CT is creating a paradigm shift in imaging standards for patients with locally recurrent and metastatic PCa. This article examines the strengths and limitations of mpMRI for initial PCa diagnosis, active surveillance, recurrent disease evaluation, and image-guided biopsies, and the use of PET/CT imaging in men with recurrent PCa. The goal of this review is to provide a rational basis for current NCCN Clinical Practice Guidelines in Oncology for PCa as they pertain to the use of these advanced imaging modalities.

Focal therapy, time to join the multi-disciplinary team discussion?

Organ preserving management is common place in renal cancer, breast cancer and many other solid organ tumours. Current strategies in managing intermediate risk prostate cancer include either whole gland treatment, in the form of radical radiotherapy or radical prostatectomy, or active surveillance. The former is associated with significant post-treatment functional morbidity, whilst the latter associated with the burden of surveillance activity and patient anxiety. Focal therapy would logically fit as a middle ground for suitable patients in whom treatment would be recommended, but where much better functional outcomes may be possible. Ideally this comes without restricting the successful prevention of harm from the cancer. Historically limitations in developing tissue preserving focal therapy strategies in prostate cancer, were due to inaccuracies in tumour characterisation prior to treatment and during follow up. Consequently for example many patients undergoing an active surveillance strategy were being upgraded and upstaged within a short period. Recently high level evidence supporting the use of MRI and targeted biopsies, in particular the PROMIS and PRECISION trials have strengthened clinician confidence in accurate disease characterisation, thus making focal therapy to become a more feasible management option. With improved diagnostic strategies and the publication of reassuring medium term oncological and functional outcomes after focal therapy for intermediate risk prostate cancer, has the time come to require consideration of focal therapy within our multi-disciplinary team (MDT) meetings and with patients? In this review we will consider patient selection and the evidence for the various focal ablation options as well as the surveillance of these patients after treatment. The forthcoming trials to determine comparative effectiveness will be discussed.

Early Diagnosis of Prostate Cancer from the Perspective of Chinese Physicians

Prostate cancer (PCa) is the seventh most diagnosed cancer and the tenth leading cause of cancer mortality in China. Unlike the USA, both incidence and mortality continue to increase. In China, PCa is often diagnosed at a locally advanced or metastatic stage, resulting in a high mortality-to-incidence ratio. Implementing regular screening using a well-validated biomarker may result in the earlier diagnosis of localized disease. Furthermore, it is important to be able to distinguish between low-grade and high-grade disease, to avoid subjecting patients to unnecessary biopsies, undertreatment of significant disease, or overtreatment of indolent disease. While prostate-specific antigen (PSA) is commonly used in PCa screening around the world, its relationship to PCa is still unclear and results vary widely across different studies. New biomarkers, imaging techniques and risk predictive models have been developed in recent years to improve upon the accurate detection of high-grade PCa. Blood- and urine-based biomarkers, such as PSA isoforms, prostate cancer antigen 3, or mRNA transcripts, have been used to improve the detection of high-grade PCa. These markers have also been used to create risk predictive models, which can further improve PCa detection. Furthermore, multiparametric magnetic resonance imaging is becoming increasingly accessible for the detection of PCa. Because of ethnic variations, biomarkers and risk predictive models validated in Western populations cannot be directly applied to Chinese men. Validation of new biomarkers and risk predictive models in the Chinese population may improve PCa screening and reduce mortality of this disease in China.

Added value of diffusion-weighted images and dynamic contrast enhancement in multiparametric magnetic resonance imaging for the detection of clinically significant prostate cancer in the PICTURE trial

OBJECTIVE

To determine the additional diagnostic value of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCE) in men requiring a repeat biopsy within the PICTURE study.

PATIENTS AND METHODS

PICTURE was a paired-cohort confirmatory study in which 249 men who required further risk stratification after a previous non-magnetic resonance imaging (MRI)-guided transrectal ultrasonography-guided biopsy underwent a 3-Tesla (3T) multiparametic (mp)MRI consisting of T2-weighted imaging (T2W), DWI and DCE, followed by transperineal template prostate mapping biopsy. Each mpMRI was reported using a LIKERT score in a sequential blinded manner to generate scores for T2W, T2W+DWI and T2W+DWI+DCE. Area under the receiver-operating characteristic curve (AUROC) analysis was performed to compare the diagnostic accuracy of each combination. The threshold for a positive mpMRI was set at a LIKERT score ≥3. Clinically significant prostate cancer was analysed across a range of definitions including UCL/Ahmed definition 1 (primary definition), UCL/Ahmed definition 2, any Gleason ≥3 + 4 and any Gleason ≥4 + 3.

RESULTS

Of 249 men, sequential MRI reporting was available for 246. There was a higher rate of equivocal lesions (44.6%) using T2W alone compared to the addition of DWI (23.9%) and DCE (19.8%). Using the primary definition of clinically significant disease, there was no significant difference in the overall accuracy between T2W, with an AUROC of 0.74 (95% confidence interval [CI] 0.68-0.80), T2W+DWI at 0.76 (95% CI 0.71-0.82), and T2W+DWI+DCE, with an AUROC of 0.77 (95% CI 0.71-0.82; P = 0.55). The AUROC values remained comparable using other definitions of clinically significant disease including UCL/Ahmed definition 2 (P = 0.79), Gleason ≥3 + 4 (P = 0.53) and Gleason ≥4 + 3 (P = 0.53).

CONCLUSIONS

Using 3T MRI, a high level of diagnostic accuracy can be achieved using T2W as a single parameter in men with a prior biopsy; however, such a strategy can lead to a higher rate of equivocal lesions.

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

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

The Role of Multiparametric MRI and MRI-targeted Biopsy in Detecting Clinically Significant Prostate Cancer in the Community Setting: A Retrospective Study

Multiparametric MRI and the Prostate Imaging-Reporting and Data System (PI-RADS) have emerged as tools to reveal suspicious prostate lesions and MRI-targeted biopsy has shown potential to avoid repeat prostate biopsies and miss fewer significant cancers. This retrospective study sought to assess the differences in diagnostic yield and sampling efficiency between MRI-targeted and standard biopsies in a community urology practice. We concluded that MRI-targeted biopsy was more efficient than a standard biopsy, although neither technique achieved a superior diagnostic yield of clinically significant cancer in our community setting. We recommend that a standard biopsy be performed alongside targeted biopsy.

Prediction of significant prostate cancer in biopsy-naïve men: Validation of a novel risk model combining MRI and clinical parameters and comparison to an ERSPC risk calculator and PI-RADS

BACKGROUND

Risk models (RM) need external validation to assess their value beyond the setting in which they were developed. We validated a RM combining mpMRI and clinical parameters for the probability of harboring significant prostate cancer (sPC, Gleason Score ≥ 3+4) for biopsy-naïve men.

MATERIAL AND METHODS

The original RM was based on data of 670 biopsy-naïve men from Heidelberg University Hospital who underwent mpMRI with PI-RADS scoring prior to MRI/TRUS-fusion biopsy 2012-2015. Validity was tested by a consecutive cohort of biopsy-naïve men from Heidelberg (n = 160) and externally by a cohort of 133 men from University College London Hospital (UCLH). Assessment of validity was performed at fusion-biopsy by calibration plots, receiver operating characteristics curve and decision curve analyses. The RM`s performance was compared to ERSPC-RC3, ERSPC-RC3+PI-RADSv1.0 and PI-RADSv1.0 alone.

RESULTS

SPC was detected in 76 men (48%) at Heidelberg and 38 men (29%) at UCLH. The areas under the curve (AUC) were 0.86 for the RM in both cohorts. For ERSPC-RC3+PI-RADSv1.0 the AUC was 0.84 in Heidelberg and 0.82 at UCLH, for ERSPC-RC3 0.76 at Heidelberg and 0.77 at UCLH and for PI-RADSv1.0 0.79 in Heidelberg and 0.82 at UCLH. Calibration curves suggest that prevalence of sPC needs to be adjusted to local circumstances, as the RM overestimated the risk of harboring sPC in the UCLH cohort. After prevalence-adjustment with respect to the prevalence underlying ERSPC-RC3 to ensure a generalizable comparison, not only between the Heidelberg and die UCLH subgroup, the RM`s Net benefit was superior over the ERSPC`s and the mpMRI`s for threshold probabilities above 0.1 in both cohorts.

CONCLUSIONS

The RM discriminated well between men with and without sPC at initial MRI-targeted biopsy but overestimated the sPC-risk at UCLH. Taking prevalence into account, the model demonstrated benefit compared with clinical risk calculators and PI-RADSv1.0 in making the decision to biopsy men at suspicion of PC. However, prevalence differences must be taken into account when using or validating the presented risk model.

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.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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