Missing the Mark: Prostate Cancer Upgrading by Systematic Biopsy over Magnetic Resonance Imaging/Transrectal Ultrasound Fusion Biopsy

Retrospective analysis of the learning curve in perineal robot-assisted prostate biopsy

INTRODUCTION

Magnetic resonance imaging-transrectal ultrasound (MRI-TRUS)-fusion biopsy (FBx) of the prostate allows targeted sampling of suspicious lesions within the prostate, identified by multiparametric MRI. Due to its reliable results and feasibility, perineal MRI/TRUS FBx is now the gold standard for prostate cancer (PC) diagnosis. There are various systems for performing FBx on the market, for example, software-based, semirobotic, or robot-assisted platform solutions. Their semiautomated workflow promises high process quality independent of the surgeon's experience. The aim of this study was to analyze how the surgeon's experience influences the cancer detection rate (CDR) via targeted biopsy (TB) and the procedure's duration in robot-assisted FBx.

PATIENTS AND METHODS

A total of 1716 men who underwent robot-assisted FBx involving a combination of targeted and systematic sampling between October 2015 and April 2022 were analyzed. We extracted data from the patients' electronic medical records retrospectively. Primary endpoints were the CDR by TB and the procedure's duration. For our analysis, surgeons were divided into three levels of experience: ≤20 procedures (little), 21-100 procedures (intermediate), and >100 procedures (high). Statistical analysis was performed via regression analyses and group comparisons.

RESULTS

Median age, prostate-specific antigen level, and prostate volume of the cohort were 67 (±7.7) years, 8.13 (±9.4) ng/mL, and 53 (±34.2) mL, respectively. Median duration of the procedure was 26 (±10.9) min. The duration decreased significantly with the surgeon's increasing experience from 35.1 (little experience) to 28.4 (intermediate experience) to 24.0 min (high experience) (p < 0.001). Using TB only, significant PC (sPC) was diagnosed in 872/1758 (49.6%) of the men. The CDR revealed no significant correlation with the surgeon's experience in either group comparison (p = 0.907) or in regression analysis (p = 0.65).

CONCLUSION

While the duration of this procedure decreases with increasing experience, the detection rate of sPC in TB is not significantly associated with the experience of the surgeon performing robot-assisted FBx. This robot-assisted biopsy system's diagnostic accuracy therefore appears to be independent of experience.

Enhancing Prostate Cancer Detection Accuracy in Magnetic Resonance Imaging-targeted Prostate Biopsy: Optimizing the Number of Cores Taken

Background and objective

The shift toward targeted biopsy (TBx) aims at enhancing prostate cancer (PCa) detection while reducing overdiagnosis of clinically insignificant disease. Despite the improved ability of TBx in identifying clinically significant PCa (csPCa), the optimal number and location of targeted cores remain unclear. This review aims to assess the optimal number of prostate biopsy magnetic resonance imaging (MRI)-targeted cores to detect csPCa.

Methods

A narrative literature search was conducted using PubMed, focusing on studies published between January 2014 and January 2024, addressing factors influencing targeted core numbers during prostate biopsy. The search included both retrospective and prospective studies, prioritizing those with substantial sample sizes and employing terms such as "prostate biopsy", "mpMRI", "core number", and "cancer detection".

Key findings and limitations

Two biopsy cores identified csPCa in 55-65% of cases. This detection rate improved to approximately 90% when the number of cores was ≥5. The inclusion of perilesional and systematic biopsies could maximize the detection of csPCa (from 10% to 45%), especially in patients under active surveillance or with prior negative biopsy results, although there is an increase in the overdiagnosis of indolent tumors (from 4% to 20%). Transperineal software-assisted target prostate biopsy may enhance cancer detection, particularly for tumors located at the apex/anterior part of the prostate. Increasing the number of TBx cores may incrementally raise the risk of complications (by 2-14% with each added core) and result in severe pain and significant discomfort for up to 17% and 25% of TBx patients, respectively. However, the overall rate and severity of these complications remain within acceptable limits.

Conclusions and clinical implications

The optimal number of cores for targeted prostate biopsies should balance minimizing sampling errors with effective cancer detection and should be tailored to each patient's unique prostate characteristics. Up to five cores per MRI target may be considered to enhance the detection of csPCa, with adjustments based on factors such as prostate and lesion volume, Prostate Imaging Reporting and Data System, biopsy techniques, complications, patient discomfort, and anxiety.

Patient summary

In this report, we found that increasing the number of biopsy cores up to ≥5 improves the detection rates of significant prostate cancer significantly to around 90%. Although inclusion of nearby and systematic biopsies enhances detection, increasing the biopsy count may lead to higher risks of complications and indolent tumors. A customized biopsy approach based on multiple variables could be helpful in determining the appropriate number of targeted biopsies on a case-by-case basis.

The distinct roles of reinforcement learning between pre-procedure and intra-procedure planning for prostate biopsy

PURPOSE

Magnetic resonance (MR) imaging targeted prostate cancer (PCa) biopsy enables precise sampling of MR-detected lesions, establishing its importance in recommended clinical practice. Planning for the ultrasound-guided procedure involves pre-selecting needle sampling positions. However, performing this procedure is subject to a number of factors, including MR-to-ultrasound registration, intra-procedure patient movement and soft tissue motions. When a fixed pre-procedure planning is carried out without intra-procedure adaptation, these factors will lead to sampling errors which could cause false positives and false negatives. Reinforcement learning (RL) has been proposed for procedure plannings on similar applications such as this one, because intelligent agents can be trained for both pre-procedure and intra-procedure planning. However, it is not clear if RL is beneficial when it comes to addressing these intra-procedure errors.

METHODS

In this work, we develop and compare imitation learning (IL), supervised by demonstrations of predefined sampling strategy, and RL approaches, under varying degrees of intra-procedure motion and registration error, to represent sources of targeting errors likely to occur in an intra-operative procedure.

RESULTS

Based on results using imaging data from 567 PCa patients, we demonstrate the efficacy and value in adopting RL algorithms to provide intelligent intra-procedure action suggestions, compared to IL-based planning supervised by commonly adopted policies.

CONCLUSIONS

The improvement in biopsy sampling performance for intra-procedure planning has not been observed in experiments with only pre-procedure planning. These findings suggest a strong role for RL in future prospective studies which adopt intra-procedure planning. Our open source code implementation is available here .

Development and validation of a predictive model based on clinical and MpMRI findings to reduce additional systematic prostate biopsy

OBJECTIVES

To develop and validate a predictive model based on clinical features and multiparametric magnetic resonance imaging (mpMRI) to reduce unnecessary systematic biopsies (SBs) in biopsy-naïve patients with suspected prostate cancer (PCa).

METHODS

A total of 274 patients who underwent combined cognitive MRI-targeted biopsy (MRTB) with SB were retrospectively enrolled and temporally split into development (n = 201) and validation (n = 73) cohorts. Multivariable logistic regression analyses were used to determine independent predictors of clinically significant PCa (csPCa) on cognitive MRTB, and the clinical, MRI, and combined models were established respectively. Area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analyses were assessed.

RESULTS

Prostate imaging data and reporting system (PI-RADS) score, index lesion (IL) on the peripheral zone, age, and prostate-specific antigen density (PSAD) were independent predictors and included in the combined model. The combined model achieved the best discrimination (AUC 0.88) as compared to both the MRI model incorporated by PI-RADS score, IL level, and zone (AUC 0.86) and the clinical model incorporated by age and PSAD (AUC 0.70). The combined model also showed good calibration and enabled great net benefit. Applying the combined model as a reference for performing MRTB alone with a cutoff of 60% would reduce 43.8% of additional SB, while missing 2.9% csPCa.

CONCLUSIONS

The combined model based on clinical and mpMRI findings improved csPCa prediction and might be useful in making a decision about which patient could safely avoid unnecessary SB in addition to MRTB in biopsy-naïve patients.

CRITICAL RELEVANCE STATEMENT

The combined model based on clinical and mpMRI findings improved csPCa prediction and might be useful in making a decision about which patient could safely avoid unnecessary SB in addition to MRTB in biopsy-naïve patients.

KEY POINTS

• Age, PSAD, PI-RADS score, and peripheral index lesion were independent predictors of csPCa. • Risk models were used to predict the probability of detecting csPCa on cognitive MRTB. • The combined model might reduce 43.8% of unnecessary SBs, while missing 2.9% csPCa.

Intensive sampling of the umbra and penumbra improves clinically significant prostate cancer detection and reduces risk of grade group upgrading at radical prostatectomy

PURPOSE

Our objective is to evaluate the clinically significant prostate cancer detection rate of overlapping and perilesional systematic biopsy cores and its impact on grade group (GG) concordance at prostatectomy.

MATERIALS AND METHODS

Biopsy maps of those undergoing MRI-targeted (TB) and systematic biopsy (SB) were reviewed to reclassify systematic cores. Perilesional (PL) cores were defined as adjacent cores within 10 mm of the target lesion ("penumbra") whilst overlap (OL) cores were defined as cores within the ROI itself ("umbra"). All other cores were designated as distant cores (DC). The incremental csPCa detection rate (GG ≥ 2) and the rate of GG upgrading on prostatectomy as OL, PL and DC sequentially added to TB were determined.

RESULTS

Out of the 398 patients included, the median number of OL and PL cores was 5 (IQR 4-7) and 5 (IQR 3-6) respectively. OL cores detected more csPCa than PL cores (31 vs 16%, p < 0.001). OL and PL cores improved the csPCa detection rate of TB from 34 to 39% (p < 0.001) and 37% (p = 0.001) respectively. TB+OL+PL had greater csPCa detection compared to just TB+OL (41 vs 39%, p = 0.016) and TB+PL (41 vs 37%, p < 0.001). Of the 104 patients who underwent prostatectomy, GG upgrading rate for TB+OL+PL was lower compared to TB (21 vs 36%, p < 0.001) and was not significantly different compared to TB+OL+PL+DC (21 vs 19%, p = 0.500).

CONCLUSION

A biopsy strategy incorporating both intensive sampling of the umbra and penumbra improved csPCa detection and reduced risk of GG upgrading at prostatectomy.

Intra-practice Urologist-level Variation in Targeted Fusion Biopsy Outcomes

OBJECTIVE

To examine the extent to which the urologist performing biopsy contributes to variation in prostate cancer detection during fusion-guided prostate biopsy.

METHODS

All men in the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry who underwent fusion biopsy at Michigan Medicine from August 2017 to March 2019 were included. The primary outcomes were clinically significant cancer detection rate (defined as Gleason Grade ≥2) in targeted cores and clinically significant cancer detection on targeted cores stratified by PI-RADS score. Bivariate and multivariable logistic regression analyses were performed.

RESULTS

A total of 1133 fusion biopsies performed by 5 providers were included. When adjusting for patient age, PSA, race, family history, prostate volume, clinical stage, and PI-RADS score, there was no significant difference in targeted clinically significant cancer detection rates across providers (range = 38.5%-46.9%, adjusted P-value = .575). Clinically significant cancer detection rates ranged from 11.1% to 16.7% in PI-RADS 3 (unadjusted P = .838), from 24.6% to 43.4% in PI-RADS 4 (adjusted P = .003), and from 69.4% to 78.8% in PI-RADS 5 (adjusted P = .766) lesions.

CONCLUSION

There was a statistically significant difference in clinically significant prostate cancer detection in PI-RADS 4 lesions across providers. These findings suggest that even among experienced providers, variation at the urologist level may contribute to differences in clinically significant cancer detection rates within PI-RADS 4 lesions. However, the relative impact of biopsy technique, radiologist interpretation, and MR acquisition protocol requires further study.

MRI-informed prostate biopsy: What the radiologist should know on quality in biopsy planning and biopsy acquisition

Quality is currently recognized as the pre-requisite for delivering the clinical benefits expected by magnetic resonance imaging (MRI)-informed prostate biopsy (MRI-i-PB) in patients with a suspicion for clinically significant prostate cancer (csPCa). The "quality chain" underlying MRI-i-PB is multidisciplinary in nature, and depends on several factors related to the patient, imaging technique, image interpretation and biopsy procedure. This review aims at making the radiologist aware of biopsy-related factors impacting on MRI-i-PB quality, both in terms of biopsy planning (threshold for biopsy decisions, association with systematic biopsy and number of targeted cores) and biopsy acquisition (biopsy route, targeting technique, and operator's experience). While there is still space for improvement and better standardization of several biopsy-related procedures, current evidence suggests that high-quality MRI-i-PB can be delivered by acquiring and increased the number of biopsy cores targeted to suspicious imaging findings and perilesional area ("focal saturation biopsy"). On the other hand, uncertainty still exists as to whether software-assisted fusion of MRI and transrectal ultrasound images can outperform cognitive fusion strategy. The role for operator's experience and quality assurance/quality control procedures are also discussed.

A comprehensive comparison between mpMRI of the prostate, MR-US fusion biopsy and whole mount histopathology

OBJECTIVES

To compare multiparametric magnetic resonance imaging (mpMRI) findings, US-MR fusion prostate biopsy results and whole-mount thin-section histopathology after radical prostatectomy.

PATIENTS AND METHODS

Overall 259 patients, who had undergone mpMRI with lesions reported as PI-RADS 3-5, underwent a MR-US fusion biopsy between 2018 and 2020. Overall 186 biopsies yielded prostate cancer and 104 patients subsequently underwent endoscopic extraperitoneal radical prostatectomy. Histopathology of biopsies was compared to the final histopathology in whole mount thin sections after radical prostatectomy by means of descriptive statistics, and further, the lesions from mpMRT were compared to whole mount histology.

RESULTS

Prostate cancer was diagnosed in 186 (71.8%) of 259 patients (median age 69.2 y, range 42-82 y, median PSA 7.8 ng/ml, range 2.1-31.3 ng/ml). Of those, 95 (51,1%) underwent radical endoscopic prostatectomy, and 80 (43%) chose radiotherapy or active surveillance. In 52/95 (54,7%) with RPE additional lesions were found in the final histological whole mount sections not described at mpMRI. 22/95 (23,2%) of RPE patients had ≥ 1 additional Gleason score ≥ 7 lesions, 23 /259 (8,4%) of biopsies, respectively. The Gleason score after surgery was upgraded in 37/95 (38,9%) and downgraded in 18/95 (18,9%) patients.

CONCLUSION

If we compare all 259 performed biopsies with the final histological whole mount sections which showed additional lesions with Gleason ≥ 7 (23,2%), it can be assumed that up to 10% of clinical significant carcinomas are missed during primary assessment via mpMRI. The majority of additional findings after RP were intermediate/high risk tumors. Upgrades from low-risk to intermediate or high-risk occurred.

Learning Curve of Transperineal MRI/US Fusion Prostate Biopsy: 4-Year Experience

This study aimed to evaluate the learning curve of transperineal magnetic resonance imaging (MRI)/ultrasound (US) fusion biopsy in a team composed of a single surgeon, a single radiologist, and a single pathologist. We prospectively enrolled 206 patients undergoing MRI/US fusion prostate biopsy and divided them into four cohorts by the year of biopsy. We analyzed temporal changes in clinically significant prostate cancer (csPC) detection rate, percentage of positive cores on biopsy, and Gleason upgrading rate after radical prostatectomy. The csPC detection rate by MRI/US fusion targeted biopsy (TB) increased significantly (from 35.3% to 60.0%, p = 0.01). With increased experience, the csPC detection rates for small (≤1 cm) and anterior target lesions gradually increased (from 41.2% to 51.6%, p = 0.5; from 54.5% to 88.2%, p = 0.8, respectively). The percentage of positive cores on TB increased significantly (from 18.4% to 44.2%, p = 0.001). The Gleason upgrading rate gradually decreased (from 22.2% to 11.1%, p = 0.4). In conclusion, with accumulated experience and teamwork, the csPC detection rate by TB significantly increased. Multidisciplinary team meetings and a free-hand biopsy technique were the key factors for overcoming the learning curve.

Individualized Decision Making in Transperineal Prostate Biopsy: Should All Men Undergo an Additional Systematic Biopsy?

Background: In prostate cancer (PC) diagnosis, additional systematic biopsy (SB) is recommended to complement MRI-targeted biopsy (TB) to address the limited sensitivity of TB alone. The combination of TB+SB is beneficial for diagnosing additional significant PC (sPC) but harmful in terms of the additional diagnosis of indolent PC (iPC), morbidity, and resource expenditures. We aimed to investigate the benefit of additional SB and to identify predictors for this outcome. Methods: We analyzed the frequency of upgrading to sPC by additional SB in a retrospective single-center cohort of 1043 men. Regression analysis (RA) was performed to identify predictors for this outcome. Reclassification rates of ISUP grade groups between prostate biopsy and a subsequent radical prostatectomy were assessed. Results: Additional SB led to upgrading to sPC in 98/1043 men (9.4%) and to the additional diagnosis of iPC in 71/1043 (6.8%). In RA, men harboring a PI-RADS 2-4 lesion were more likely to have TB results upgraded by SB (p < 0.01) compared to PI-RADS 5 men. When analyzing reclassification rates, additional SB reduced the upgrading to sPC from 43/214 (20.1%) to 8/214 (3.7%). In the PI-RADS 5 subgroup, this difference decreased: 4/87 (4.7%) with TB only vs. 1/87 (1.2%) with TB+SB. Conclusion: Men with a PI-RADS 5 lesion may obviate additional SB.

Paradigm Shift in Prostate Cancer Diagnosis: Pre-Biopsy Prostate Magnetic Resonance Imaging and Targeted Biopsy

With regard to the indolent clinical characteristics of prostate cancer (PCa), the more selective detection of clinically significant PCa (CSC) has been emphasized in its diagnosis and management. Magnetic resonance imaging (MRI) has advanced technically, and recent international cooperation has provided a standardized imaging and reporting system for prostate MRI. Accordingly, prostate MRI has recently been investigated and utilized as a triage tool before biopsy to guide tissue sampling to increase the detection rate of CSC beyond the staging tool for patients in whom PCa was already confirmed on conventional systematic biopsy. Radiologists must understand the current paradigm shift for better PCa diagnosis and management. This article reviewed the recent literature, demonstrating the diagnostic value of pre-biopsy prostate MRI with targeted biopsy and discussed unsolved issues regarding the paradigm shift in the diagnosis of PCa.

Development of a nomogram combining multiparametric magnetic resonance imaging and PSA-related parameters to enhance the detection of clinically significant cancer across different region

OBJECTIVE

Prostate cancer (PCa) is the most prevalent cancer among males. This study attempted to develop a clinically significant prostate cancer (csPCa) risk nomogram including Prostate Imaging-Reporting and Data System (PI-RADS) score and other clinical indexes for initial prostate biopsy in light of the different prostate regions, and internal validation was further conducted.

PATIENTS AND METHODS

A retrospective study was performed including 688 patients who underwent ultrasound-guided transperineal magnetic resonance imaging fusion prostate biopsy from December 2016 to July 2019. We constructed nomograms combining PI-RADS score and clinical variables (prostate-specific antigen [PSA], prostate volume (PV), age, free/total PSA, and PSA density) through univariate and multivariate logistic regression to identify patients eligible for biopsy. The performance of the predictive model was evaluated by bootstrap resampling. The area under the curve (AUC) of the receiver-operating characteristic (ROC) analysis was appointed to quantify the accuracy of the primary nomogram model for csPCa. Calibration curves were used to assess the agreement between the biopsy specimen and the predicted probability of the new nomogram. The χ² test was also applied to evaluate the heterogeneity between fusion biopsy and systematic biopsy based on different PI-RADS scores and prostate regions.

RESULTS

A total of 320 of 688 included patients were diagnosed with csPCa. csPCa was defined as Gleason score ≥7. The ROC and concordance-index both presented good performance. The nomogram reached an AUC of 0.867 for predicting csPCa at the peripheral zone; meanwhile, AUC for transitional and apex zones were 0.889 and 0.757, respectively. Statistical significance was detected between fusion biopsy and systematic biopsy for PI-RADS score >3 lesions and lesions at the peripheral and transitional zones.

CONCLUSION

We produced a novel nomogram predicting csPCa in patients with suspected imaging according to different locations. Our results indicated that PI-RADS score combined with other clinical parameters showed a robust predictive capacity for csPCa before prostate biopsy. The new nomogram, which incorporates prebiopsy data including PSA, PV, age, and PI-RADS score, can be helpful for clinical decision-making to avoid unnecessary biopsy.

Application of Shear Wave Elastography and Contrast-Enhanced Ultrasound in Transrectal Prostate Biopsy

OBJECTIVE

To explore the clinical value of ultrasound shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) in transrectal prostate biopsy.

METHODS

A total of 54 patients (average age: 67.79±12.01 years) in the experimental group underwent transrectal prostate biopsy under the guidance of SWE, while 46 patients (average age: 69.22±11.54 years) in the control group underwent transrectal prostate biopsy guided by CEUS.

RESULTS

There were a total of 451 needles, with an average of 8.35±1.67 needles per patient in the experimental group, and a total of 462 needles, with an average of 10.04±1.33 needles per patient in the control group. The difference in puncture times between the two groups was statistically significant (P<0.05). There was no significant difference in the positive detection rate, sensitivity or specificity between the two groups (P>0.05), but there was a significant difference in the diagnostic accuracy between the two groups (P<0.05). The E_mean and E_max of prostate cancer were significantly higher in the experimental group than in benign prostatic hyperplasia (P<0.05). The receiver operating characteristic curve (ROC) analysis showed that the area under the ROC curve (AUC) of E_mean was 0.752 (S.E. =0.072, 95% CI=0.611-0.894, P=0.007), and the best cutoff value was 47.005 kPa.

CONCLUSION

In summary, both SWE- and CEUS-guided transrectal prostate biopsy can help find the focus and guide the puncture, and improve the positive detection rate.

Predicting the Performance of Concurrent Systematic Random Biopsies during Image Fusion Targeted Sampling of Multi-Parametric MRI Detected Prostate Cancer. A Prospective Study (PRESET Study)

Simple Summary

The study provides a predictive model by using clinical factors in selecting men who may benefit from the addition of systematic biopsies with an image fusion targeted approach. The approach is likely to improve the detection of csPCa and avoid unnecessary detection of indolent prostate cancers.

Abstract

The study was aimed to develop a predictive model to identify patients who may benefit from performing systematic random biopsies (SB) in addition to targeted biopsies (TB) in men suspected of having prostate cancer. A total of 198 patients with positive pre-biopsy MRI findings and who had undergone both TB and SB were prospectively recruited into this study. The primary outcome was detection rates of clinically significant prostate cancer (csPCa) in SB and TB approaches. The secondary outcome was net clinical benefits of SB in addition to TB. A logistic regression model and nomogram construction were used to perform a multivariate analysis. The detection rate of csPCa using SB was 51.0% (101/198) compared to a rate of 56.1% (111/198) for TB, using a patient-based biopsy approach. The detection rate of csPCa was higher using a combined biopsy (64.6%; 128/198) in comparison to TB (56.1%; 111/198) alone. This was statistically significant (p < 0.001). Age, PSA density and PIRADS score significantly predicted the detection of csPCa by SB in addition to TB. A nomogram based on the model showed good discriminative ability (C-index; 78%). The decision analysis curve confirmed a higher net clinical benefit at an acceptable threshold.

Results from a PI-RADS-based MRI-directed diagnostic pathway for biopsy-naive patients in a non-university hospital

Purpose

To assess the safety and performance of a MRI-directed diagnostic pathway for patients with first-time suspicion of prostate cancer in a non-university hospital.

Methods

Between May 2017 and December 2018 all biopsy-naive patients examined in our hospital followed a MRI-directed diagnostic work-up algorithm based on PI-RADS score. In short, PI-RADS 1–2 was generally not biopsied and PI-RADS 3–5 was reviewed by a multidisciplinary team. Patients with PI-RADS 4-5 were all referred to biopsy, either transrectal ultrasound-guided biopsy or MRI in-bore biopsy for small tumors and for sites difficult to access. PI-RADS scores were compared to the histopathology from biopsies and surgical specimens for patients who had prostatectomy. Non-biopsied patients were referred to a safety net monitoring regimen.

Results

Two hundred and ninety-eight men were enrolled. 97 (33%) had PI-RADS 1–2, 44 (15%) had PI-RADS 3, and 157 (53%) had PI-RADS 4–5. 116 (39%) of the patients avoided biopsy. None of these were diagnosed with significant cancer within 2–3.5 years of safety net monitoring. Almost all high ISUP grade groups (≥ 3) were in the PI-RADS 4–5 category (98%). Prostatectomy specimens and systematic biopsies from MRI-negative areas indicated that very few clinically significant cancers were missed by the MRI-directed diagnostic pathway.

Conclusion

Our findings add to evidence that a MRI-directed diagnostic pathway can be safely established in a non-university hospital. The pathway reduced the number of biopsies and reliably detected the site of the most aggressive cancers.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00261-021-03249-8.

A prospective study on inter-operator variability in semi-robotic software-based MRI/TRUS-fusion targeted prostate biopsies

Purpose

Magnetic resonance imaging (MRI)/ultrasound-fusion prostate biopsy (FB) comprises multiple steps each of which can cause alterations in targeted biopsy (TB) accuracy leading to false-negative results. The aim was to assess the inter-operator variability of software-based fusion TB by targeting the same MRI-lesions by different urologists.

Methods

In this prospective study, 142 patients eligible for analysis underwent software-based FB. TB of all lesions (n = 172) were carried out by two different urologists per patient (n = 31 urologists). We analyzed the number of mismatches [overall prostate cancer (PCa), clinically significant PCa (csPCa) and non-significant PCa (nsPCa)] between both performed TB per patient. In addition we evaluated factors contributing to inter-operator variability by uni- and multivariable analyses.

Results

In 11.6% of all MRI-lesions (10.6% of all patients) there was a mismatch between TB1 and TB2 in terms of overall prostate cancer (PCa detection. Regarding csPCa, patient-based mismatch occurred in 14.8% (n = 21). Overall PCa and csPCa detection rate of TB1 and TB2 did not differ significantly on a per-patient and per-lesion level.

Analyses revealed a smaller lesion size as predictive for mismatches (OR 9.19, 95% CI 2.02–41.83, p < 0.001).

Conclusion

Reproducibility and precision of targeting particularly small lesions is still limited although using software-based FB. Further improvements in image-fusion, segmentation, needle-guidance, and automatization are necessary.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-021-03891-3.

Why Does Magnetic Resonance Imaging-Targeted Biopsy Miss Clinically Significant Cancer?

PURPOSE

Multiple studies demonstrate magnetic resonance imaging (MRI)-targeted biopsy detects more clinically significant cancer than systematic biopsy; however, some clinically significant cancers are detected by systematic biopsy only. While these events are rare, we sought to perform a retrospective analysis of these cases to ascertain the reasons that MRI-targeted biopsy missed clinically significant cancer which was subsequently detected on systematic prostate biopsy.

MATERIALS AND METHODS

Patients were enrolled in a prospective study comparing cancer detection rates by transrectal MRI-targeted fusion biopsy and systematic 12-core biopsy. Patients with an elevated prostate specific antigen (PSA), abnormal digital rectal examination, or imaging findings concerning for prostate cancer underwent prostate MRI and subsequent MRI-targeted and systematic biopsy in the same setting. The subset of patients with grade group (GG) ≥3 cancer found on systematic biopsy and GG ≤2 cancer (or no cancer) on MRI-targeted biopsy was classified as MRI-targeted biopsy misses. A retrospective analysis of the MRI and MRI-targeted biopsy real-time screen captures determined the cause of MRI-targeted biopsy miss. Multivariable logistic regression analysis compared baseline characteristics of patients with MRI-targeted biopsy misses to GG-matched patients whose clinically significant cancer was detected by MRI-targeted biopsy.

RESULTS

Over the study period of 2007 to 2019, 2,103 patients met study inclusion criteria and underwent combined MRI-targeted and systematic prostate biopsies. A total of 41 (1.9%) men were classified as MRI-targeted biopsy misses. Most MRI-targeted biopsy misses were due to errors in lesion targeting (21, 51.2%), followed by MRI-invisible lesions (17, 40.5%) and MRI lesions missed by the radiologist (3, 7.1%). On logistic regression analysis, lower Prostate Imaging-Reporting and Data System (PI-RADS^TM) score was associated with having clinically significant cancer missed on MRI-targeted biopsy.

CONCLUSIONS

While uncommon, most MRI-targeted biopsy misses are due to errors in lesion targeting, which highlights the importance of accurate co-registration and targeting when using software-based fusion platforms. Additionally, some patients will harbor MRI-invisible lesions which are untargetable by MRI-targeted platforms. The presence of a low PI-RADS score despite a high PSA is suggestive of harboring an MRI-invisible lesion.

Quantitative ultrasound shear wave elastography (USWE)-measured tissue stiffness correlates with PIRADS scoring of MRI and Gleason score on whole-mount histopathology of prostate cancer: implications for ultrasound image-guided targeting approach

OBJECTIVE

To correlate quantitative tissue stiffness measurements obtained by transrectal ultrasound shear wave elastography (USWE) with PI-RADS scoring of multiparametric magnetic imaging resonance (mpMRI) using Gleason scores of radical prostatectomy as a reference standard.

PATIENTS AND METHODS

196 men with localised prostate cancer were prospectively recruited into the study and had quantitative prostate tissue stiffness measurements in kilopascals (kPa) using transrectal USWE prior to radical prostatectomy. PI-RADS scores of mpMRI were also obtained in all the men. Imaging and histopathology of radical prostatectomy specimen were oriented to each other using patient specific customised 3D moulds to guide histopathology grossing of radical prostatectomy specimens. All included patients had confirmed PCa on TRUS-guided biopsies, had both USWE and mpMRI imaging data, and underwent radical prostatectomy. Chi-square test with 95% confidence interval was used to assess the difference between Gleason score (GS) of radical prostatectomy and PI-RADS classification, as well as GS of radical prostatectomy and stiffness (in Kpa) using USWE. The correlation coefficient (r) was calculated in order to investigate relation between PI-RADS classification and tissue stiffness in kPa.

RESULTS

There was a statistically significant correlation between USWE-measured tissue stiffness and GS (χ2 (2, N = 196) = 23.577, p < 0.001). Also, there was a statistically significant correlation between Gleason score and PI-RADS score (χ2 (2, N = 196) = 12.838, p = 0.002). High PIRADS on MRI and high stiffness on USWE (> 100 kPa) detected more than 80% and 90% high risk prostate cancer disease. However, a weak correlation coefficient of 0.231 was observed between PI-RADS score and level of tissue stiffness measured in kPa.

CONCLUSION

Quantitative USWE and mpMRI using PI-RADS classification provide a good degree of prediction for Gleason score of clinically significant prostate cancer (csPCa). Stiffer lesions on ultrasound showed a weak correlation with PI-RADS scoring system. USWE could be used to target suspected prostate cancer.

Limitations of overlapping cores in systematic and MRI-US fusion biopsy

OBJECTIVES

To evaluate the clinically-significant prostate cancer (csCaP) detection rate of systematic (SBx) vs. targeted biopsy (TBx), after accounting for the overlapping systematic cores within the MRI regions of interest.

MATERIALS AND METHODS

We identified 398 consecutive men who underwent both transperineal systematic and targeted biopsy between January 2015 to January 2019. We reclassified overlapping systematic cores in the MRI regions of interest as target cores. The detection rates of SBx and TBx were compared using McNemar's test.

RESULTS

Detection rate of csCaP (grade group ≥2) was 42% (168/398). Median number of systematic and targeted cores were 23 (IQR 19-29) and 9 (IQR 6-12) respectively. A median of 3 (IQR 2-4) overlapping systematic cores were reclassified as targeted cores. After accounting for overlap, csPC detection rate on SBx decreased from 37% and 21% while the csCaP detection rate of TBx increased from 34% to 39% (both P < 0.001), with TBx having a better detection rate (39% vs. 21%, P < 0.001). A previous negative biopsy was associated with a lower risk of having csCaP on non-targeted SBx (OR 0.27, 95% CI: 0.12 - 0.58, P = 0.001). Only 5% (13/243) of those who had no cancer detected on TBx had csCaP on non-targeted SBx compared to 45% (70/155) of those who had csCaP on TBx (P< 0.001).

CONCLUSIONS

The utility of SBx in detecting csCaP decreases after accounting for overlap into the MRI region of interest, especially in men with a prior negative biopsy. Overlapping systematic cores improve the csCaP detection rate on TBx.

Single-cell Spatial Proteomic Revelations on the Multiparametric MRI Heterogeneity of Clinically Significant Prostate Cancer

PURPOSE

Multiparametric MRI (mpMRI) has become an indispensable radiographic tool in diagnosing prostate cancer. However, mpMRI fails to visualize approximately 15% of clinically significant prostate cancer (csPCa). The molecular, cellular, and spatial underpinnings of such radiographic heterogeneity in csPCa are unclear.

EXPERIMENTAL DESIGN

We examined tumor tissues from clinically matched patients with mpMRI-invisible and mpMRI-visible csPCa who underwent radical prostatectomy. Multiplex immunofluorescence single-cell spatial imaging and gene expression profiling were performed. Artificial intelligence-based analytic algorithms were developed to examine the tumor ecosystem and integrate with corresponding transcriptomics.

RESULTS

More complex and compact epithelial tumor architectures were found in mpMRI-visible than in mpMRI-invisible prostate cancer tumors. In contrast, similar stromal patterns were detected between mpMRI-invisible prostate cancer and normal prostate tissues. Furthermore, quantification of immune cell composition and tumor-immune interactions demonstrated a lack of immune cell infiltration in the malignant but not in the adjacent nonmalignant tissue compartments, irrespective of mpMRI visibility. No significant difference in immune profiles was detected between mpMRI-visible and mpMRI-invisible prostate cancer within our patient cohort, whereas expression profiling identified a 24-gene stromal signature enriched in mpMRI-invisible prostate cancer. Prostate cancer with strong stromal signature exhibited a favorable survival outcome within The Cancer Genome Atlas prostate cancer cohort. Notably, five recurrences in the 8 mpMRI-visible patients with csPCa and no recurrence in the 8 clinically matched patients with mpMRI-invisible csPCa occurred during the 5-year follow-up post-prostatectomy.

CONCLUSIONS

Our study identified distinct molecular, cellular, and structural characteristics associated with mpMRI-visible csPCa, whereas mpMRI-invisible tumors were similar to normal prostate tissue, likely contributing to mpMRI invisibility.

Is Additional Systematic Biopsy Necessary in All Initial Prostate Biopsy Patients With Abnormal MRI?

Purpose

To determine whether additional systematic biopsy is necessary in all biopsy naïve patients with MRI visible lesions by taking PI-RADS score and prostate volume into consideration.

Materials and Methods

Patients who underwent combined systematic biopsy (SB) and cognitive MRI-targeted biopsy (TB) in our hospital between May 2018 and June 2020 were retrospectively reviewed. The detection rate of clinical significant prostate cancer (csPCa), biopsy grade group (GG) concordance, and disease upgrading rate on radical prostatectomy were compared between SB and TB and further stratified by PI-RADS v2.0 category and prostate volume.

Results

A total of 234 patients were analyzed in this study. TB alone detected more csPCa and less clinically insignificant prostate cancer (cisPCa) than SB alone in the whole cohort (57.3 vs 53%, P = 0.041; 3.8 vs 7.7%, P = 0.049 respectively). The additional SB indicated only a marginal increase of csPCa detection but a remarkable increase of cisPCa detection compared with targeted biopsy (59.4 vs 57.3%, P = 0.064; 3.8 vs 7.7%, P = 0.012). As stratified by PI-RADS category, the difference of csPCa detection rate between TB and SB was not significant either in PI-RADS 5 subgroup (83.8 vs 76.3%, P = 0.07) or in PI-RADS 3–4 subgroup (43.5 vs 40.9%, P = 1.0). Additional SB decreased the rate of disease upgrading on radical prostatectomy (RP) than TB alone in PI-RADS 3–4 subgroup (14.5 vs 25.5%, P = 0.031) other than PI-RADS 5 subgroup (6 vs 6%, P = 1.0). When stratified by prostate volume (PV), TB alone detected more csPCa than SB in small prostate (PV < 30 ml) group (81.0 vs 71.0%, P = 0.021) but not in large prostate (PV ≥ 30 ml) group (44.0 vs 42.7%, P = 0.754). The additional SB did not significantly decrease the rate of disease upgrading on RP than TB alone in either small or large prostate (6.4 vs 8.5%, P = 1.0; 13.8 vs 22.4%, P = 0.063).

Conclusion

The combination biopsy method was no superior than targeted biopsy alone in PI-RADS 5 or in small volume prostate subgroup.

Reasons for missing clinically significant prostate cancer by targeted magnetic resonance imaging/ultrasound fusion-guided biopsy

OBJECTIVES

This study evaluates cases with clinically significant prostate cancer (csPCa) missed by targeted biopsy (TB) and analyzes the diagnostic impact of an additional systematic biopsy (SB) in a large patient collective.

METHODS

Consecutive patients with a 3 T multiparametric prostate MRI (mpMRI) and a subsequent MRI/US fusion-guided TB plus 12-core US-guided SB from 01/2014 to 04/2019 were included in this study. Primary study endpoint was the analysis of cases with a csPCa missed by TB and detected by SB. Secondary study objectives were the PCa detection and the correlation with clinical and MRI parameters.

RESULTS

In total 785 patients met the inclusion criteria. 342 patients had a csPCa (median PSAD 0.29 ng/mL/cm³). In 42 patients (13 %), a csPCa was detected only by SB. In 36 of these cases, the localization of the positive SB cores matched with the cancer suspicious region described on mpMRI (mCSR). Cases with a csPCA missed by TB showed either an insufficient MRI segmentation (prostate boundary correlation) (31 %) and/or insufficient lesion registration (lesion transfer, tracking, and/or matching) (48 %), a missed small lesion (14 %), or a failed center of a large lesion (10 %). Median PSAD of patients with non-significant PCa detected by SB was 0.15 ng/mL/cm³.

CONCLUSIONS

Main reasons for missing a csPCa by TB were insufficient prostate segmentation or imprecise lesion registration within MRI/US fusion-guided biopsy. Consequently, verification of MRI quality, exact mCSR assessment, and advanced biopsy experience may improve accuracy. Altogether, an additional SB adds limited clinical benefit in men with PSAD ≤ 0.15 ng/mL/cm³.

Transperineal systematic biopsies in addition to targeted biopsies are important in the detection of clinically significant prostate cancer

BACKGROUND

This study aimed to determine whether the addition of transperineal systematic biopsies (SB) to targeted biopsies (TB) improved clinically significant prostate cancer (csPC) detection rates without high increase in insignificant prostate cancer detection rates in an Australian population.

METHODS

In this retrospective review, a total of 254 patients who had a Prostate Imaging-Reporting and Data System score between 3 and 5, and a transperineal TB and SB between 2014 and 2019 from two centres were included in this study. The primary outcome of this study was to determine csPC rates on TB and SB. The secondary outcome was a comparison of the Gleason Grade Group between TB and SB. csPC was defined as an International Society of Urological Pathology Gleason Grade Group of 2 or greater.

RESULTS

SB alone detected more csPC overall compared to TB (152/254 (60%) versus 128/254 (51%), respectively). An additional 40 of 254 (16%) csPC cases were diagnosed with the addition of SB. Furthermore, the cost of diagnosing insignificant prostate cancer by SB when TB were negative was an additional 13/254 (5.1%).

CONCLUSION

A combination of TB and SB provides the best outcomes for detecting csPC and is especially warranted for patients with a higher Prostate Imaging-Reporting and Data System score on multiparametric magnetic resonance imaging.

The utility of in-bore multiparametric magnetic resonance-guided biopsy in men with negative multiparametric magnetic resonance-ultrasound software-based fusion targeted biopsy

OBJECTIVES

To evaluate the utility of in-bore multiparametric magnetic resonance-guided biopsy of the prostate (IB) in patients with visible lesion/s and previous negative software-based multiparametric magnetic resonance imaging/ultrasonography fusion-targeted biopsy of the prostate (FTB).

PATIENTS AND METHODS

We retrospectively analysed prospectively maintained database including consecutive men undergoing IB from March 2013 to October 2017 in 2 European centres expert in this procedure. We selected men with the following criteria: No previous treatment for prostate cancer (CaP), multiparametric magnetic resonance imaging (mpMRI) lesion(s) PIRADS score ≥ 3, FTB showing no clinically significant cancer (csCaP), and subsequent IB. Patient's characteristics, mpMRI findings, biopsy technique, and histopathological results were extracted. The primary outcome was to determine the detection rate of csCaP, defined as any Gleason pattern ≥ 4. A multivariable analysis was performed to identify predictors of positive findings at IB.

RESULTS

Fifty-three men were included. Median age was 68 years (interquartile range [IQR] 64-68), median Prostate-Specific Antigen (PSA) was 7.6 ng/ml (IQR 5.2-10.9), and median prostate volume was 59 ml (IQR 44-84). Fifty-six lesions with PIRADS score 3 in 9 cases (16%), 4 in 30 cases (54%), and 5 in 17 cases (30%) were detected. FTB was performed in all cases using a transrectal approach with 3 different platforms (Toshiba, Koelis, and Artemis). Median time between FTB and IB was 3 months (IQR 1-7). A median of 2 cores per lesion were collected with IB (IQR 2-3). No cancer, clinically insignificant and clinically significant cancer were found in 33 (59%), 9 (16%), and 14 (25%) targeted lesions, respectively. Median maximum cancer core length and maximum positive percentage were 9 mm (3-13) and 55% (21%-80%). The only predictor of csCaP on IB was prostate volume (P = 0.026) with an ideal cut-off at 70 ml.

CONCLUSION

One in 4 patients with previous negative FTB, IB was able to detect csCaP. According to this study, IB would be of particularly useful in patients with large glands.

The role of multiparametric resonance and biopsy in prostate cancer detection: comparison with definitive histological report after laparoscopic/robotic radical prostatectomy

Purpose

Magnetic Resonance Imaging (MRI) targeted biopsy increases overall detection rates and decreases the risk of clinically insignificant PCa detection. The aim of this retrospective study is to compare concordance rates regarding side of lesion and Gleason Score at fusion targeted/systematic biopsy and MRI with the definitive histologic report of prostatectomy specimen.

Methods

115 patients underwent multiparametric (mp) MRI and successively fusion targeted/systematic biopsy. 107 patients, with a positive biopsy for PCa, further underwent laparoscopic/robotic radical prostatectomy. We compared surgical histologic report with biopsy histologic report for side of lesion and Gleason Score. We further compared PIRADS score at mpMRI with Gleason Score of both histologic reports.

Results

Concordance rate for mpMRI lesion side was 74% compared to biopsy and 52.3% compared to surgical histologic report (p < 0.0001). Fusion targeted/systematic biopsy reported a concordance rate with surgical histologic report of 67.3% for side of the lesion, while Gleason Score was concordant for 73.6% for clinically significant cancer (Gleason Score ≥ 7) (p < 0.0001). PIRADS score ≥ 3 was further associated with clinically significant cancer at surgical histologic report in 92.4% of cases (p = 0.359).

Conclusion

Multiparametric MRI of the prostate reaches a good and improvable accuracy in the detection of suspicious PCa before biopsy. A combined approach of fusion targeted and systematic biopsy could further increase the overall accuracy in PCa diagnosis, especially in biopsy-naïve patients, reaching concordance rates with definitive histologic report up to 52.3% and 85.5%.

Transperineal prostate biopsy: a review of technique

As the second most diagnosed cancer worldwide, prostate cancer is confirmed via tissue biopsy. Given the large number of prostate biopsies performed each year, the technique should be as accurate and safe as possible for the patient’s well-being. Transrectal ultrasound guided prostate biopsy (TRUS-biopsy) is most offered worldwide. Transperineal biopsy (TPP-biopsy), on the other hand, has been gaining popularity due to its superior sensitivity and lower rate of sepsis. This article offers a review of the brachytherapy grid technique used to perform a TPP-biopsy, as well as a discussion of possible variations in the procedure. TPP-biopsy is typically performed under general anaesthesia with patient in lithotomy. Through the perineum, cores of tissue are taken systematically, with or without targeting, under US guidance. Different fusion techniques (cognition, MRI-US fusion software, MRI in-bore) can be used to target pre-identified lesions on MRI. The sampling can be done either by free hand or using a brachytherapy grid. Robotic assisted prostate biopsy is also available on the market as an alternative. In recent years, there has been accumulating evidence showing that it is safe and feasible to perform TPPB under local anaesthesia. This may improve the uptake of TPPB as the preferred biopsy technique for prostate cancer.

Magnetic resonance imaging-ultrasound fusion-targeted biopsy combined with systematic 12-core ultrasound-guided biopsy improves the detection of clinically significant prostate cancer: Are we ready to abandon the systematic approach?

Background:

Multiparametric (mp) magnetic resonance imaging (MRI)–ultrasound fusion-targeted biopsy (TB) has improved the detection of clinically significant prostate cancer (csCaP) using the Prostate Imaging Reporting and Data System (PI-RADS) reporting system, leading some authors to conclude that TB can replace the 12-core systematic biopsy (SB). We compared the diagnostic performance of TB with SB at our institution.

Methods:

Eighty-three men with elevated prostate-specific antigen levels (6.6 ng/mL, interquartile range [IQR] 4.5–9.2) and abnormal mp-MRI (127 lesions, PI-RADS ≥3, median size: 1.1 cm, IQR 0.8–1.6) underwent simultaneous TB and SB. Diagnosis of any CaP (Gleason score, [GS] ≥6) and csCaP (GS ≥7) was compared using the McNemar's exact test.

Results:

SB showed higher, but not statistically significant, detection rates of any CaP and csCaP (51.8% and 34.9%) versus TB (44.6% and 28.9%) (P = 0.286 and P = 0.359, respectively). TB outperformed SB in the quantification of 56.6% CaP and detecting cancer in anterior sectors (7.2%). Compared to SB, TB missed twice the amount of any CaP and csCaP. SB alone detected 22.2% of all csCaPs and upgraded 20.6% of TB-detected CaP. SB identified cancer invisible on mp-MRI (13.7% of all CaP) or missed by TB due to a small size (<1 cm) and sampling error (7% of lesions).

Conclusion:

A combination of SB with TB remained necessary for achieving the highest cancer detection rates. Limiting prostate biopsy to TB alone can miss csCaP due to the presence of synchronous high-grade cancer invisible on MRI or failure to hit the target. TB is the best approach for anterior lesions and tumor quantification.

Yield of concurrent systemic biopsy during MRI-targeted biopsy according to Prostate Imaging Reporting and Data System version 2 in patients with suspected prostate cancer

OBJECTIVES

To investigate the yield of concurrent systemic biopsy (SB) during MRI-targeted biopsy (MRTB) as Prostate Imaging Reporting and Data System (PI-RADS) version 2 (v2) interpretations in patients with suspected prostate cancer (PCa).

METHODS

A total of 285 patients with suspected PCa underwent prebiopsy 3-T MRI, followed by MRI-transrectal ultrasound fusion targeted biopsy and concurrent standard SB for lesions with PI-RADS v2 scores 3-5. Detection rates and positive core rates of PCa and clinically significant cancer (CSC) were evaluated.

RESULTS

In concurrent MRTB and SB, PCa and CSC detection rates were 18.9% and 9.4% for PI-RADS score 3, 45.9% and 32.4% for PI-RADS score 4, and 82.1% and 72.6% for PI-RADS score 5, respectively. Overall detection rate of CSCs (40.0%) for concurrent MRTB and SB was significantly higher than that of MRTB (34.4%, p = 0.004) or SB alone (27.7%, p < 0.001): an increase of 5.6% (16 patients) compared with MRTB alone. For patients with PI-RADS score 4 or 5, the CSC detection rate of concurrent MRTB and SB was 47.0%, an increase of 6.1% when compared with MRTB (40.9%) only (p < 0.001). Of the 110 patients with both MRTB- and SB-positive findings, 22 (20.0%) had the highest Gleason score in SB compared with that in MRTB. In 9.5% (27/285) patients including 12 patients with CSCs, only SB was positive, with negative MRTB.

CONCLUSION

Concurrent SB with MRTB based on PI-RADS v2 can yield a higher CSC detection rate compared with MRTB alone in patients with suspected PCa.

KEY POINTS

• Concurrent SB with MRTB yields an increase of 5.6% CSC detection compared with MRTB alone. • Of both MRTB- and SB-positive findings, 20.0% patients have upgraded Gleason score in SB. • In 18.4% patients, only SB was positive, with negative MRTB. Adding MRTB to SB is helpful for adequate risk stratification, reducing diagnostic uncertainty of PCa.

Mosquito proboscis-inspired needle insertion to reduce tissue deformation and organ displacement

This study investigates mosquito proboscis-inspired (MPI) insertion applied to the clinically used biopsy needle to reduce tissue deformation and organ displacement. Advanced medical imagining has enabled early-stage identification of cancerous lesions that require needle biopsy for minimally invasive tissue sampling and pathological analysis. Accurate cancer diagnosis depends on the accuracy of needle deployment to the targeted cancerous lesion site. However, currently available needle delivery systems deform and move soft tissue and organs, leading to a non-diagnostic biopsy or undersampling of the target. Two features inspired by the mosquito proboscis were adopted for MPI insertion in prostate biopsy: (1) the harpoon-shape notches at the needle tip and (2) reciprocating needle-cannula motions for incremental insertion. The local tissue deformation and global prostate displacement during the MPI vs. traditional direct insertions were quantified by optically tracking the displacement of particle-embedded tissue-mimicking phantoms. Results show that the MPI needle insertion reduced both local tissue deformation and global prostate displacement because of the opposite needle-cannula motions and notches which stabilized and reduced the tissue deformation during insertion. Findings provide proof of concept for MPI insertion in the clinical biopsy procedures as well as insights of needle–tissue interaction for future biopsy technology development.

Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: Experience of the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel

Background Prostate MRI is used widely in clinical care for guiding tissue sampling, active surveillance, and staging. The Prostate Imaging Reporting and Data System (PI-RADS) helps provide a standardized probabilistic approach for identifying clinically significant prostate cancer. Despite widespread use, the variability in performance of prostate MRI across practices remains unknown. Purpose To estimate the positive predictive value (PPV) of PI-RADS for the detection of high-grade prostate cancer across imaging centers. Materials and Methods This retrospective cross-sectional study was compliant with the HIPAA. Twenty-six centers with members in the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel submitted data from men with suspected or biopsy-proven untreated prostate cancer. MRI scans were obtained between January 2015 and April 2018. This was followed with targeted biopsy. Only men with at least one MRI lesion assigned a PI-RADS score of 2-5 were included. Outcome was prostate cancer with Gleason score (GS) greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2). A mixed-model logistic regression with institution and individuals as random effects was used to estimate overall PPVs. The variability of observed PPV of PI-RADS across imaging centers was described by using the median and interquartile range. Results The authors evaluated 3449 men (mean age, 65 years ± 8 [standard deviation]) with 5082 lesions. Biopsy results showed 1698 cancers with GS greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2) in 2082 men. Across all centers, the estimated PPV was 35% (95% confidence interval [CI]: 27%, 43%) for a PI-RADS score greater than or equal to 3 and 49% (95% CI: 40%, 58%) for a PI-RADS score greater than or equal to 4. The interquartile ranges of PPV at these same PI-RADS score thresholds were 27%-44% and 27%-48%, respectively. Conclusion The positive predictive value of the Prostate Imaging and Reporting Data System was low and varied widely across centers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Milot in this issue.

Prostate MRI with PI-RADS v2.1: initial detection and active surveillance

The role of prostate MRI in clinical practice has continued to broaden over time. Multiple iterations of PI-RADS reporting have aided in improving detection and reporting of prostate cancer. In addition, recent recommendations from the PI-RADS Steering Committee promote an MRI-first approach with an MRI-directed prostate cancer diagnostic pathway. It is imperative for radiologists to be knowledgeable and familiar with prostate MRI and PI-RADS recommendations, as there is an increasing demand for prostate imaging by clinicians and patients alike.

Value of extra-target prostate biopsy for the detection of magnetic resonance imaging-missed adverse pathology according to the Prostate Imaging Reporting and Data System scores: Spatial analysis using magnetic resonance-ultrasound fusion images

OBJECTIVES

To clarify who benefits from extra-target sampling of systematic prostate biopsy to detect magnetic resonance imaging-missed significant cancer and upgrading, when concurrently carried out with magnetic resonance imaging-ultrasound fusion targeted biopsy.

METHODS

Targeted biopsy and systematic biopsy were carried out in 301 men with Prostate Imaging Reporting and Data System scores ≥3. All score ≥3 regions were designated as targets. According to patients' highest Prostate Imaging Reporting and Data System scores, spatial relations between targets and biopsy-proven cancer were investigated to identify magnetic resonance imaging-missed pathology.

RESULTS

Overall, targeted biopsy and systematic biopsy detected significant cancer in 56.5% and 46.5%, respectively (P < 0.001). Significant cancer was detected only by systematic biopsy in 7.0%, and only outside targets in 5.0%. Upgrading by systematic biopsy was observed in 16.3%, and occurred outside targets in 11.0%. On multivariate analysis, the highest Prostate Imaging Reporting and Data System 4 was predictive for significant cancer only outside targets (odds ratio 5.81, P = 0.002) and for upgrading derived from outside targets (odds ratio 2.64, P = 0.012). According to the scores of 3, 4 and 5, significant cancer was identified only outside targets in 1.0%, 11.2% and 2.9%, respectively (P = 0.003 for Prostate Imaging Reporting and Data System 3 vs 4; P = 0.019 for Prostate Imaging Reporting and Data System 4 vs 5), and upgrading occurred in 6.1%, 18.4% and 8.6%, respectively (P = 0.009 and 0.040).

CONCLUSIONS

Men with the highest Prostate Imaging Reporting and Data System score 4 receive the largest benefit from extra-target biopsy for magnetic resonance imaging-missed significant cancer detection and upgrading. In men with a score of 3, less adverse pathology is missed without extra-target biopsy. These findings suggest prostate biopsy strategy could be tailored according to Prostate Imaging Reporting and Data System scores.

Value of systematic sampling in an mp-MRI targeted prostate biopsy strategy

The clinical utility of systematic prostate biopsy in addition to multi-parametric magnetic resonance imagining (mp-MRI) targeted biopsy pathways remains unclear. Despite radiological advancements in mp-MRI and utilisation of international standardised reporting systems (i.e., PI-RADS, LIKERT), undetected clinically significant prostate cancer (csPCa) on imaging persists. This has prevented the widespread adoption of an exclusively targeted biopsy approach. The current evidence on csPCa cancer detection rates in mp-MRI targeted alone and combined with a non-targeted systematic sampling is presented. Arguments for and against routine limited systematic sampling as an adjunct to an mp-MRI targeted biopsy are discussed. Our review will report the clinical utility of a combined sampling strategy on csPCa detection rate. The available evidence suggests that we are yet to reach a stage where non-targeted systematic prostate biopsy can be routinely omitted in mp-MRI targeted prostate biopsy pathways. Research should focus on improving the accuracy of mp-MRI, prostate biopsy techniques, and in identifying those men that will most benefit from a combined prostate biopsy. Such strategies may help future urologists reduce the burden of non-targeted cores in modern mp-MRI prostate biopsy pathways.

Diagnostic Value of Transrectal Shear Wave Elastography for Prostate Cancer Detection in Peripheral Zone: Comparison with Magnetic Resonance Imaging

Objective: To assess the diagnostic value of transrectal shear wave elastography (SWE) for detecting prostate cancer (PCa) in peripheral zone and compare it with magnetic resonance imaging (MRI). Materials and Methods: Two hundred twenty-one patients suspected of PCa were enrolled, in which 172 patients of them underwent both SWE and MRI. Elastic value was measured in the area prepared for systematic biopsy and suspicious lesion detected on B-mode or SWE, histopathological result was compared for each biopsy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were derived by obtaining optimal threshold from receiver operating characteristic (ROC) curve. The correlation between the stiffness of PCa and Gleason scores, prognostic grades, and percentage of cancer in biopsy were evaluated by Spearman rank correlation. Multivariate logistic regression analysis was performed to determine predictors for diagnosing PCa. The diagnostic capacity of MRI and SWE for detecting PCa and clinically significant PCa in the peripheral zone were assessed by comparing area under curve of ROC curve. Results: A value of 42 kPa was used as the cutoff for differentiating benign from malignant prostatic tissue; the sensitivity, specificity, PPV, NPV, and accuracy were 78.97%, 90.67%, 71.30%, 93.66% and 88.03%, respectively. Rank correlation analysis revealed that the stiffness of PCa had a correlation with Gleason score, prognostic grade, and percentage of cancer in biopsy. On multivariate analysis, the age, free prostate-specific antigen (PSA), PSA density, SWE, and MRI were independent predictors for diagnosing PCa. There was no statistical difference for diagnosing PCa between SWE and MRI (p = 0.259). However, for clinically significant PCa, the diagnostic capacity of SWE was a little higher than MRI (p = 0.013). Conclusions: SWE may provide additional information for PCa detection, which could increase the positive rate of PCa in targeted biopsy and reduce unnecessary biopsy. SWE is compatible with MRI for detecting PCa in the peripheral zone.

The impact of time from biopsy to radical prostatectomy on Gleason score undergrading and other related factors

INTRODUCTION

Gleason score biopsy undergrading (GSBU) can have an impact on the management and prognosis of patients with prostate cancer. We analyze the possible impact of time and other clinical and analytical factors in the appearance of GSBU in our series.

PATIENTS AND METHOD

Ambispective, multicenter study of 1955 patients with localized prostate cancer undergoing radical prostatectomy between 2005 and 2018. Descriptive statistics and hypothesis testing are reported by univariate and multivariate analyses.

RESULTS

Mean age 63.69 (44-80) years, median PSA 8.70 ng / ml (1.23-99). GSBU was observed in 34.7% of the entire cohort. In 72.8% of the cases, the GSBU occurred in one consecutive Gleason score, with the progression from 3 + 3 to 3 + 4 being the most frequent (289 patients, 47.6%). Performing radical prostatectomy 90-180 days before or after the biopsy does not have an impact on its undergrading in any of the groups. In the univariate and multivariate analysis, the presence of tumor or pathological rectal examination in both lobes, the tumor load ≥50% of cylinders and a DPSA ≥0.20, showed independent discriminative capacity to select patients who presented GSBU.

CONCLUSIONS

The time from biopsy to radical prostatectomy did not show impact on GSBU. The number of affected cylinders, bilateral tumor and DPSA are easily accessible parameters that can help us select patients with greater probability of presenting GSBU.

Needle deflection and tissue sampling length in needle biopsy

This study investigates the effect of needle tip geometry on the needle deflection and tissue sampling length in biopsy. Advances in medical imaging have allowed the identification of suspicious cancerous lesions which then require needle biopsy for tissue sampling and subsequent confirmatory pathological analysis. Precise needle insertion and adequate tissue sampling are essential for accurate cancer diagnosis and individualized treatment decisions. However, the single-bevel needles in current hand-held biopsy devices often deflect significantly during needle insertion, causing variance in the targeted and actual locations of the sampled tissue. This variance can lead to inaccurate sampling and false-negative results. There is also a limited understanding of factors affecting the tissue sampling length which is a critical component of accurate cancer diagnosis. This study compares the needle deflection and tissue sampling length between the existing single-bevel and exploratory multi-bevel needle tip geometries. A coupled Eulerian-Lagrangian finite element analysis was applied to understand the needle-tissue interaction during needle insertion. The needle deflection and tissue sampling length were experimentally studied using tissue-mimicking phantoms and ex-vivo tissue, respectively. This study reveals that the tissue separation location at the needle tip affects both needle deflection and tissue sampling length. By varying the tissue separation location and creating a multi-bevel needle tip geometry, the bending moments induced by the insertion forces can be altered to reduce the needle deflection. However, the tissue separation location also affects the tissue contact inside the needle groove, potentially reducing the tissue sampling length. A multi-bevel needle tip geometry with the tissue separation point below the needle groove face may reduce the needle deflection while maintaining a long tissue sampling length. Results from this study can guide needle tip design to enable the precise needle deployment and adequate tissue sampling for the needle biopsy procedures.

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.

Developments in MRI-targeted prostate biopsy

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Targeted biopsy: benefits and limitations

PURPOSE OF REVIEW

To review the current literature regarding the role of multiparametric MRI and fusion-guided biopsies in urologic practice.

RECENT FINDINGS

Fusion biopsies consistently show an increase in the detection of clinically significant cancers and decrease in low-risk disease that may be more suitable for active surveillance. Although, when to incorporate multiparametric MRI into workup is not clearly agreed upon, studies have shown a clear benefit in both biopsy naïve and those with prior negative biopsies in determining the appropriate treatment strategy. More recently, cost-analysis models have been published that show that upfront MRIs are more cost-effective when considering missed cancers and treatment courses.

SUMMARY

With improved accuracy over systematic biopsies, fusion biopsies are a superior method for detection of the true grade of cancer for both biopsy naïve and patients with prior negative biopsies, choosing appropriate candidates for active surveillance, and monitoring progression on active surveillance.

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

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

Spatial distribution of biopsy cores and the detection of intra-lesion pathologic heterogeneity

Objectives:

The objective of this study was to determine if spatial distribution of multiparametric magnetic resonance imaging–transrectal ultrasound (mpMRI-TRUS) fusion biopsy cores to the index lesion reveals trends in the detection of intra-lesion Gleason heterogeneity and a more optimal prostate biopsy strategy.

Methods:

Index lesion was the lesion with longest diameter on T2-weighted (T2W)-MRI. In cohort 1, fusion biopsy cores biopsies were taken in areas in the center of the target as well as 1 cm laterally on each side. For cohort 2, targeted biopsies were taken from the center of the lesion only. Heterogeneity was defined as difference in maximum Gleason score obtained from fusion cores in the center of the index lesion versus cores obtained from the periphery (cohort 1), or any difference in maximum Gleason score obtained from fusion cores targeted to the index lesion (cohort 2) compared with systematic 12 cores TRUS biopsy.

Results:

Ninety-nine consecutive patients (35 and 64 in cohorts 1 and 2, respectively) with median age (SD) and prostate-specific antigen (PSA) of 66.9 (±5.9) and 9.7 (±8.2) respectively, were included. Age, PSA, Prostate Imaging Reporting and Data System (PI-RADS) score, and preoperative MRI lesion size were not significantly different between cohorts. Gleason heterogeneity was observed at a significantly higher rate in cohort 1 versus cohort 2 (58% versus 24%; p = 0.041). In cohort 1, cores obtained from the center of the lesion had higher Gleason score than cores obtained from the periphery of the targeted lesion in 57% of cases.

Conclusions:

We demonstrate that there is observable tumor heterogeneity in biopsy specimens, and that increased number of cores, as well as cores focused on the center and periphery of the largest lesion in the prostate, provide more comprehensive diagnostic information about the patient’s clinical risk category than taking nonspecific cores targeted within the tumor.

Prostate Imaging-Reporting and Data System Steering Committee: PI-RADS v2 Status Update and Future Directions

CONTEXT

The Prostate Imaging-Reporting and Data System (PI-RADS) v2 analysis system for multiparametric magnetic resonance imaging (mpMRI) detection of prostate cancer (PCa) is based on PI-RADS v1, accumulated scientific evidence, and expert consensus opinion.

OBJECTIVE

To summarize the accuracy, strengths and weaknesses of PI-RADS v2, discuss pathway implications of its use and outline opportunities for improvements and future developments.

EVIDENCE ACQUISITION

For this consensus expert opinion from the PI-RADS steering committee, clinical studies, systematic reviews, and professional guidelines for mpMRI PCa detection were evaluated. We focused on the performance characteristics of PI-RADS v2, comparing data to systems based on clinicoradiologic Likert scales and non-PI-RADS v2 imaging only. Evidence selections were based on high-quality, prospective, histologically verified data, with minimal patient selection and verifications biases.

EVIDENCE SYNTHESIS

It has been shown that the test performance of PI-RADS v2 in research and clinical practice retains higher accuracy over systematic transrectal ultrasound (TRUS) biopsies for PCa diagnosis. PI-RADS v2 fails to detect all cancers but does detect the majority of tumors capable of causing patient harm, which should not be missed. Test performance depends on the definition and prevalence of clinically significant disease. Good performance can be attained in practice when the quality of the diagnostic process can be assured, together with joint working of robustly trained radiologists and urologists, conducting biopsy procedures within multidisciplinary teams.

CONCLUSIONS

It has been shown that the test performance of PI-RADS v2 in research and clinical practice is improved, retaining higher accuracy over systematic TRUS biopsies for PCa diagnosis.

PATIENT SUMMARY

Multiparametric magnetic resonance imaging (MRI) and MRI-directed biopsies using the Prostate Imaging-Reporting and Data System improves the detection of prostate cancers likely to cause harm, and at the same time decreases the detection of disease that does not lead to harms if left untreated. The keys to success are high-quality imaging, reporting, and biopsies by radiologists and urologists working together in multidisciplinary teams.

Evaluating the size criterion for PI-RADSv2 category 5 upgrade: is 15 mm the best threshold?

PURPOSE

The purpose of the study was to determine if the ≥ 15 mm threshold currently used to define PIRADS 5 lesions is the optimal size threshold for predicting high likelihood of clinically significant (CS) cancers.

MATERIALS

Three hundred and fifty-eight lesions that may be changed from category 4 to 5 or vice versa on the basis of the size criterion (category 4: n = 288, category 5: n = 70) from 255 patients were evaluated. Kendall's tau-b statistic accounting for inter-lesion correlation, generalized estimation equation logistic regression, and receiver operating curve analysis evaluated two lesion size-metrics (lesion diameter and relative lesion diameter-defined as lesion diameter/prostate volume) for ability to identify CS (Gleason grade ≥ 3 + 4) cancer at targeted biopsy. Optimal cut-points were identified using the Youden index. Analyses were performed for the whole prostate (WP) and zone-specific sub-cohorts of lesions in the peripheral and transition zones (PZ and TZ).

RESULTS

Lesion diameter showed a modest correlation with Gleason grade (WP: τB = 0.21, p < 0.0001; PZ: τB = 0.13, p = 0.02; TZ: τB = 0.32, p = 0.001), and association with CS cancer detection (WP: AUC = 0.63, PZ: AUC = 0.59, TZ: AUC = 0.74). Empirically derived thresholds (WP: 14 mm, PZ: 13 mm, TZ: 16 mm) performed similarly to the current ≥ 15 mm standard. Lesion relative lesion diameter improved identification of CS cancers compared to lesion diameter alone (WP: τB = 0.30, PZ: τB = 0.24, TZ: τB = 0.42, all p < 0.0001). AUC also improved for WP and PZ lesions (WP: AUC = 0.70, PZ: AUC = 0.68, and TZ: AUC = 0.74).

CONCLUSIONS

The current ≥ 15 mm diameter threshold is a reasonable delineator of PI-RADS category 4 and category 5 lesions in the absence of extraprostatic extension to predict CS cancers. Additionally, relative lesion diameter can improve identification of CS cancers and may serve as another option for distinguishing category 4 and 5 lesions.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Accuracy of elastic fusion biopsy in daily practice: Results of a multicenter study of 2115 patients

OBJECTIVES

To assess the accuracy of Koelis fusion biopsy for the detection of prostate cancer and clinically significant prostate cancer in the everyday practice.

METHODS

We retrospectively enrolled 2115 patients from 15 institutions in four European countries undergoing transrectal Koelis fusion biopsy from 2010 to 2017. A variable number of target (usually 2-4) and random cores (usually 10-14) were carried out, depending on the clinical case and institution habits. The overall and clinically significant prostate cancer detection rates were assessed, evaluating the diagnostic role of additional random biopsies. The cancer detection rate was correlated to multiparametric magnetic resonance imaging features and clinical variables.

RESULTS

The mean number of targeted and random cores taken were 3.9 (standard deviation 2.1) and 10.5 (standard deviation 5.0), respectively. The cancer detection rate of Koelis biopsies was 58% for all cancers and 43% for clinically significant prostate cancer. The performance of additional, random cores improved the cancer detection rate of 13% for all cancers (P < 0.001) and 9% for clinically significant prostate cancer (P < 0.001). Prostate cancer was detected in 31%, 66% and 89% of patients with lesions scored as Prostate Imaging Reporting and Data System 3, 4 and 5, respectively. Clinical stage and Prostate Imaging Reporting and Data System score were predictors of prostate cancer detection in multivariate analyses. Prostate-specific antigen was associated with prostate cancer detection only for clinically significant prostate cancer.

CONCLUSIONS

Koelis fusion biopsy offers a good cancer detection rate, which is increased in patients with a high Prostate Imaging Reporting and Data System score and clinical stage. The performance of additional, random cores seems unavoidable for correct sampling. In our experience, the Prostate Imaging Reporting and Data System score and clinical stage are predictors of prostate cancer and clinically significant prostate cancer detection; prostate-specific antigen is associated only with clinically significant prostate cancer detection, and a higher number of biopsy cores are not associated with a higher cancer detection rate.

Prostate imaging features that indicate benign or malignant pathology on biopsy

Accurate diagnosis of clinically significant prostate cancer is essential in identifying patients who should be offered treatment with curative intent. Modifications to the Gleason grading system in recent years show that accurate grading and reporting at needle biopsy can improve identification of clinically significant prostate cancers. Extracapsular extension of prostate cancer has been demonstrated to be an adverse prognostic factor with greater risk of metastatic spread than organ-confined disease. Tumor volume may be an independent prognostic factor and should be considered in conjunction with other factors. Multi-parametric magnetic resonance imaging (MP-MRI) has become an increasingly important tool in the diagnosis and characterization of prostate cancer. MP-MRI allows T2-weighted (T2W) anatomical imaging to be combined with functional and physiological assessment. Diffusion-weighted imaging (DWI) has shown greater sensitivity, specificity and negative predictive value compared to prostate specific antigen (PSA) testing and T2W imaging alone and has a more positive correlation with Gleason score and tumour volume. Dynamic gadolinium contrast-enhanced (DCE) imaging can exhibit difficulties in distinguishing prostatitis from malignancy in the peripheral zone, and between benign prostatic hyperplasia (BPH) and malignancies in the transition zone (TZ). Computer aided diagnosis utilizes software to aid radiologists in detecting and diagnosing abnormalities from diagnostic imaging. New techniques of quantitative MRI, such as VERDICT MRI use tissue-specific factors to delineate different cellular and microstructural phenotypes, characterizing tissue properties with greater detail. Proton MR spectroscopic imaging (MRSI) is a more technically challenging imaging modality than DCE and DWI MRI. Over the last decade, choline and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) have developed as better tools for staging than conventional imaging. While hyperpolarized MRI shows promise in improving the imaging and differentiation of benign and malignant lesions there is further work required. Accurate reading and interpretation of diagnostic investigations is key to accurate identification of abnormal areas requiring biopsy, sparing those in whom benign or indolent disease can be managed by non-invasive means. Embracing and advancing existing technologies is essential in furthering this process.