Multiparametric Magnetic Resonance Imaging for the Detection of Clinically Significant Prostate Cancer: What Urologists Need to Know. Part 2: Interpretation

BackgroundThere is large variability among radiologists in their detection of clinically significant (cs) prostate cancer (PCa) on multiparametric magnetic resonance imaging (mpMRI).ObjectiveTo reduce the interpretation variability and achieve optimal accuracy in assessing prostate mpMRI.Design, setting, and participantsHow the interpretation of mpMRI can be optimized is demonstrated here. Whereas part 1 of the “surgery-in-motion” paper focused on acquisition, this paper shows the correlation between (ab)normal prostate anatomical structures and image characteristics on mpMRI, and how standardized interpretation according to Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) should be performed. This will be shown in individual patients.Surgical procedureTo detect csPCa, three mpMRI “components” are used: “anatomic” T2-weighted imaging, “cellular-density” diffusion-weighted imaging, and “vascularity” dynamic contrast-enhanced MRI.MeasurementsBased on PI-RADS v2, the accompanying video shows how mpMRI interpretation is performed. Finally, the role of mpMRI in detecting csPCa is briefly discussed and the main features of the recently introduced PI-RADS v2.1 are evaluated.Results and limitationsWith PI-RADS v2, it is possible to quantify normal and abnormal anatomical structures within the prostate based on its imaging features of the three mpMRI “components.” With this knowledge, a more objective evaluation of the presence of a csPCa can be performed. However, there still remains quite some space to reduce interobserver variability.ConclusionsFor understanding the interpretation of mpMRI according to PI-RADS v2, knowledge of the correlation between imaging and (ab)normal anatomical structures on the three mpMRI components is needed.Patient summaryThis second surgery-in-motion contribution shows what structures can be recognized on prostate magnetic resonance imaging (MRI). How a radiologist performs his reading according to the so-called Prostate Imaging Reporting and Data System criteria is shown here. The main features of these criteria are summarized, and the role of prostate MRI in detecting clinically significant prostate cancer is discussed briefly.     

The accuracy of prostate cancer diagnosis in biopsy-naive patients using combined magnetic resonance imaging and transrectal ultrasound fusion-targeted prostate biopsy

BackgroundThis study aimed to estimate whether multiparametric magnetic resonance imaging (mpMRI)-transrectal ultrasound (TRUS) fusion biopsy (FUS-TB) increases the detection rates of clinically significant prostate cancer (csPCa) compared with TRUS-guided systematic biopsy (TRUS-GB).MethodsThis retrospective study focused on patients who underwent mpMRI before prostate biopsy (PB) with Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) scores ≥3 and prostate-specific antigen (PSA) level between 2.5 and 20 ng/mL. Before FUS-TB, the biopsy needle position was checked virtually using three-dimensional mapping. After confirming the position of the target within the prostate, biopsy needle was inserted and PB was performed. Suspicious lesions were generally targeted with 2 to 4 cores. Subsequently, 10–12 cores were biopsied for TRUS-GB. The primary endpoint was the PCa detection rate (PCDR) for patients with PCa who underwent combined FUS-TB and TRUS-GB.ResultsAccording to PI-RADS v2, 76.7% of the patients with PI-RADS v2 score ≥3 were diagnosed with PCa. The PCDRs in patients with PI-RADS v2 score of 4 or 5 were significantly higher than those in patients with PI-RADS v2 score of 3 (3 vs. 4, P<0.001; 3 vs. 5, P<0.001; 4 vs. 5, P=0.073). According to PCDR, the detection rates of PCa and csPCa in the FUS-TB were significantly higher than that in the TRUS-GB.ConclusionsFollowing detection of suspicious tumor lesions on mpMRI, FUS-TB use detects a higher number of PCa cases compared with TRUS-GB.     

Predictive model containing PI-RADS v2 score for postoperative seminal vesicle invasion among prostate cancer patients

BackgroundSeminal vesicle invasion (SVI) is considered to be one of most adverse prognostic findings in prostate cancer, affecting the biochemical progression-free survival and disease-specific survival. Multiparametric magnetic resonance imaging (mpMRI) has shown excellent specificity in diagnosis of SVI, but with poor sensitivity. The aim of this study is to create a model that includes the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score to predict postoperative SVI in patients without SVI on preoperative mpMRI.MethodsA total of 262 prostate cancer patients without SVI on preoperative mpMRI who underwent radical prostatectomy (RP) at our institution from January 2012 to July 2019 were enrolled retrospectively. The prostate-specific antigen levels in all patients were <10 ng/mL. Univariate and multivariate logistic regression analyses were used to assess factors associated with SVI, including the PI-RADS v2 score. A regression coefficient-based model was built for predicting SVI. The receiver operating characteristic curve was used to assess the performance of the model.ResultsSVI was reported on the RP specimens in 30 patients (11.5%). The univariate and multivariate analyses revealed that biopsy Gleason grade group (GGG) and the PI-RADS v2 score were significant independent predictors of SVI (all P<0.05). The area under the curve of the model was 0.746 (P<0.001). The PI-RADS v2 score <4 and Gleason grade <8 yielded only a 1.8% incidence of SVI with a high negative predictive value of 98.2% (95% CI, 93.0–99.6%).ConclusionsThe PI-RADS v2 score <4 in prostate cancer patients with prostate-specific antigen level <10 ng/mL is associated with a very low risk of SVI. A model based on biopsy Gleason grade and PI-RADS v2 score may help to predict SVI and serve as a tool for the urologists to make surgical plans.     

Histology results of systematic prostate biopsies by in-bore magnetic resonance imaging vs. transrectal ultrasound

IntroductionWe aimed to compare systematic biopsies (SBs) of in-bore magnetic resonance-guided prostate biopsy (MRGpB) with those performed under transrectal ultrasound (TRUS) guidance in the clinical setting.MethodsData on all 161 consecutive patients undergoing prostate biopsy at our institution between November 2017 and July 2019 were retrospectively collected. The patients were referred to biopsy due to elevated prostate-specific antigen (PSA) and/or abnormal digital rectal examination (DRE) and/or at least one Prostate Imaging Reporting and Data System (PI-RADS) lesion score of ≥3 on multiparametric magnetic resonance imaging (mpMRI). We included patients with PSA levels ≤20 ng/ml and those with 8–12 core biopsies. Histology results of SBs performed by in-bore MRGpB were compared to TRUS SBs. Chi-squared, Fischer’s exact, and multivariate Pearson regression tests were used for statistical analysis (SPSS, IBM Corporation).ResultsIn total, 128 patients were eligible for analysis. Their median age was 68 years (interquartile range [IQR] 61.5–72), mean prostate size 55±29 cc, and mean PSA and PSA density levels 7.6±3.5 ng/ml and 0.18±0.13 ng/ml/cc, respectively. Thirty-five patients (27.3%) had suspicious DRE findings. Both biopsy groups were similar for these parameters. Thirty-eight (62.3%) MRGpB patients had a previous biopsy vs. five (7.1%) TRUS-SB patients (p<0.0001). The number of patients diagnosed with clinically significant and non-significant disease was similar for both groups. High-risk disease was more prevalent in the TRUS-SB group (22.4% vs. 4.9%, p<0.01).ConclusionsOur data suggest that in-bore MRGpB is no better than TRUS for guiding SBs for the detection of clinically significant prostate cancer.     

Effects of “real life” prostate MRI inter-observer variability on total needle samples and indication for biopsy

PurposeProstate multiparametric magnetic resonance imaging (mpMRI) improves diagnosis of clinically significant cancer and reduces over-detection of nonsignificant cancer. Disagreement in the interpretation of mpMRI readings is well-known, with a reported discrepancy rate of 10% to 42%. We report the clinical repercussions of this variability on prostate biopsy candidates.Materials and MethodsMedical records of patients referred from 11 medical centers for MR-guided prostate biopsy (MRGpB) between October, 2017 and January, 2019 were retrospectively analyzed. Patients with at least one prostate imaging reporting and data system (PI-RADS) 3 or greater prostate lesion were selected, and the mpMRI studies (all read by others) were reviewed by our prostate mpMRI reader. Outcomes included changes in PI-RADS score and the subsequent effect on total needle samples and indication for biopsy.ResultsEighty-two patients with 128 lesions were suitable for analysis (mean age 66.5 ± 7.1 years, mean PSA 6.8 ± 8.5 ng/ml). Nine (11%) patients had suspicious rectal exams (T2a). Following our prostate mpMRI reader's imaging revisions, the PI-RADS score was downgraded in 66 (52%) lesions, upgraded in 15 (12%), and unchanged in 47 (37%), leaving a total of 84 suspected lesions (kappa = 0.17). Biopsy was deferred in 22 (27%) patients, and an estimated 136.4 (34.4%) samples were avoided (P = 0.0001 for both). There was a trend toward prostate size to correlate with imaging revision and abortion of biopsy (P = 0.06) while enrollment in active surveillance correlated with proof from such outcome (P = 0.007).ConclusionThese data suggest that high interobserver disagreement in prostate mpMRIs from diverse institutes significantly affects prostate biopsy practice. The clinical consequences of this discord are significant.     

A magnetic resonance imaging-based nomogram for predicting clinically significant prostate cancer at radical prostatectomy

PurposeTo develop a nomogram incorporating clinical and multiparametric magnetic resonance imaging (mpMRI) parameters for the detection of clinically significant prostate cancer (csCaP) at radical prostatectomy (RP).Materials and MethodsWe retrospectively analyzed all consecutive patients who underwent robotic RP between 2016 and 2020. All patients underwent a 1.5-T mp-MRI according to the PI-RADS-v2 scoring system. RP specimens were examined with the whole-mount technique. csCaP definition: any tumor with a volume larger than 0.5 cm³ or with a Gleason score ≥7. Univariable logistic regression models explored the association between clinical and imaging data and the risk of csCaP. Significant variables (P < 0.05) were selected into multivariable regression models to identify independent predictors. A nomogram was designed to select the significant relevant predictors. The nomogram was internally validated in terms of discrimination and calibration. Receiver operating characteristics of the area under the curve was used to assess the discrimination ability of the nomogram. To assess the predictive performance of mpMRI, the accuracy of the mpMRI-based nomogram was compared with that excluding either PI-RADS score or mpMRI IL size.ResultsThe analysis involved 393 patients. The median age was 65(9) years. The median prostate specific antigen was 5.81(3.76) ng/ml. 363 had csCaP. PI-RADS v2 score of 4-5, prostate specific antigen density of 0.15 or more, and mpMRI index lesion (IL) size were significantly associated with csCaP in the multivariable regression analyses. Based on these variables, a diagnostic model was developed. The full model yielded an area under the curve of 0.77 (95%CI:0.75–0.80) which was significantly better than those excluding mpMRI findings (P = 0.02) Decision curve analysis showed a slight but significant net benefit associated with the use of the mp-MRI based nomograms compared with those excluding either PI-RADS score (Delta net benefit 0.0278) or mpMRI maximum IL size (Delta net benefit 0.0111).ConclusionsThe nomogram constructed in this study can assist urologists in assessing an individual's risk of csCaP at RP.     

Prostate zonal anatomy correlates with the detection of prostate cancer on multiparametric magnetic resonance imaging/ultrasound fusion–targeted biopsy in patients with a solitary PI-RADS v2–scored lesion

PurposeTo evaluate the positive predictive value (PPV) of the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) assessment method in patients with a single suspicious finding on prostate multiparametric magnetic resonance imaging (mpMRI).Patients and methodsA total of 176 patients underwent MRI/ultrasound fusion–targeted prostate biopsy after the detection of a single suspicious finding on mpMRI. The PPV for cancer detection was determined based on PI-RADS v2 assessment score and location.ResultsFusion biopsy detected prostate cancer in 60.2% of patients. Of these patients, 69.8% had Gleason score (GS) ≥7 prostate cancer. Targeted biopsy detected 90.5% of all GS≥7 prostate cancer. The PPV for GS≥7 detection of PI-RADS v2 category 5 (P5) and category 4 (P4) lesions was 70.2% and 37.7%, respectively. This increased to 88% and 38.5% for P5 and P4 lesions in the peripheral zone (PZ), respectively. Targeted biopsy did not miss GS≥7 disease compared with systematic biopsy in P5 lesions in the PZ and transition zone.ConclusionThe PPV of PI-RADS v2 for prostate cancer in patients with a single lesion on mpMRI is dependent on PI-RADS assessment category and location. The highest PPV was for a P5 lesion in the PZ.     

PI-RADS score is associated with biochemical control and distant metastasis in men with intermediate-risk and high-risk prostate cancer treated with radiation therapy

BackgroundNovel methods of risk stratification are needed for men with prostate cancer. The Prostate Imaging Reporting and Data System (PI-RADS) uses multiparametric MRI (mpMRI) to assign a score indicating the likelihood of clinically significant prostate cancer. We evaluated pretreatment mpMRI findings, including PI-RADS score, as a marker for outcome in patients treated with primary radiation therapy (RT).MethodsOne hundred and twenty-three men, 64% and 36% of whom had National Comprehensive Cancer Network (NCCN) intermediate-risk and high-risk disease, respectively, underwent mpMRI prior to RT. PI-RADS score and size of the largest nodule were analyzed with respect to freedom from biochemical failure (FFBF) and freedom from distant metastasis.ResultsA PI-RADS score of ≤3, 4, or 5 was defined in 7%, 49%, and 44%; with a median nodule size of 0, 8, and 18 mm, respectively (P < 0.001). Median follow-up was 67 months. Men with PI-RADS ≤ 3, 4, or 5 disease had 7-year FFBF of 100%, 92%, and 65% (P = 0.002), and a 7-year freedom from distant metastasis of 100%, 100%, and 82%, respectively (P = 0.014). PI-RADS (Hazard Ratio 5.4 for PI-RADS 5 vs. 4, P = 0.006) remained associated with FFBF when controlling for NCCN risk category (P = 0.063) and receipt of androgen deprivation therapy (P = 0.535). Nodule size was also associated with FFBF (Hazard Ratio 1.08 per mm, P < 0.001) after controlling for NCCN risk category (P = 0.156) and receipt of androgen deprivation therapy (P = 0.776).ConclusionmpMRI findings, including PI-RADS score and nodule size, may improve risk stratification in men treated with primary RT     

The clinical impact of Prostate Imaging–Reporting and Data System classification in patients with haemospermia undergoing multiparametric magnetic resonance imaging of the prostate

In this study, we evaluated the role of the Prostate Imaging–Reporting and Data System (PI-RADS) classification of multiparametric magnetic resonance imaging (mpMRI) to determine the likelihood of prostate cancer (PCa) in patients with haemospermia. Fifty-one patients presenting with haemospermia between 2018 and 2020 were included in this retrospective study. Forty-two of the patients (82.4%) were over 40 years, and the median prostate-specific antigen (PSA) level was 1.4 ng/ml. Fourteen of the patients (27.5%) had recurrent haemospermia. All patients underwent mpMRI, and assessments were classified according to PI-RADS v2. The mpMRI revealed PI-RADS one to four lesions in 10 (19.6%), 30 (58.8%), 6 (11.8%) and 5 (9.8%) patients respectively. One patient with PI-RADS 3 and five with PI-RADS 4 lesions underwent cognitive fusion prostate biopsy depending on MRI findings, and two patients with PI-RADS 4 lesions were diagnosed with PCa. Patients with haemospermia and risk factors, that is aged over 40 years, a high PSA level or familial history of PCa, need a more thorough evaluation with mpMRI.     

A high-fidelity,virtual-reality,transurethral resection of bladder tumor simulator: Validation as a tool for training

IntroductionSimulation-based training is used to help trainees learn surgical procedures in a safe environment. The objective of our study was to test the face, content, and construct validity of the transurethral resection of bladder tumor (TURBT) module built on the Simbionix TURP Mentor simulator.MethodsParticipants performed five standardized cases on the simulator. Domains of the simulator were evaluated on a five-point Likert scale to establish face and content validity. Construct validity was assessed through the simulator’s built-in scoring metrics, as well as video recordings of the simulator screen and an anonymized view of participants’ hands and feet, which were evaluated using an objective structured assessment of technical skills (OSATS) tool.ResultsTen experienced operators and 15 novices participated. Face validity was somewhat acceptable (mean realism 3.8/5±1.03 standard deviation [SD]; mean appearance 4.1/5±0.57), as was content validity, represented by simulation of key steps (mean 3.9±0.57). The simulator failed to achieve construct validity. There was no difference in mean simulator scores or OSATS scoring between experienced operators and novices. Novices significantly improved their mean simulator scores (305.9 vs. 332.4, p=0.006) and OSATS scoring (15.8 vs. 18.1, p=0.001), while 87% felt their confidence to perform TURBT improved. Overall, 92% of participants agreed that the simulator should be incorporated into residency training.ConclusionsOur study suggests a role for the TURBT module of the Simbionix TURP Mentor simulator as an introduction to TURBT for urology trainees. Strong support was found from both experienced operators and novices for its formal inclusion in resident education.     

Central zone lesions on magnetic resonance imaging: Should we be concerned?

Introduction and objective

The Prostate Imaging Reporting and Data System (PI-RADS) score was developed to evaluate lesions in the peripheral and transition zone on multiparametric magnetic resonance imaging (mpMRI) of the prostate. We aim to determine if the PI-RADS scoring system can be used to evaluate central zone lesions on mpMRI.

Does the Prostate Imaging-Reporting and Data System (PI-RADS) version 2 improve accuracy in reporting anterior lesions on multiparametric magnetic resonance imaging (mpMRI)?

Introduction

Multiparametric MRI (mpMRI) is useful in detecting anterior prostate tumours. Due to the location of anterior tumours, they are often diagnosed with a large size and may be suspicious for extra-prostatic extension (EPE). We aim to evaluate whether PI-RADS v2 is more accurate in assessing anterior prostate lesions identified on mpMRI compared to PI-RADS v1.

Methods

Patients with anterior prostate lesions diagnosed on mpMRI who proceeded to a cognitive fusion transperineal prostate biopsy were identified. Each mpMRI was blinded and read by two experienced prostate MRI radiologists and assigned a PI-RADS v1 and PI-RADS v2 score, and the presence of EPE was estimated. Correlation was made with transperineal histopathology and, where relevant, radical prostatectomy histopathology. Concordance measures between PI-RADS v1 and PI-RADS v2, and between examiners of the same PI-RADS score were calculated using a weighted kappa.

Results

Fifty-eight consecutive men were identified. Concordance between the examiners for PI-RADS v1 and for v2 showed substantial agreement (version 1: weighted kappa 0.71; version 2: weighted kappa 0.69). There was no difference in accuracy when using PI-RADS v1 or PI-RADS v2 to predict clinically significant cancer. There was poor correlation between EPE measured on mpMRI compared with EPE in radical prostatectomy histopathology.

Conclusion

PI-RADS v2 is reproducible between radiologists but does not have improved accuracy for diagnosing anterior tumours of the prostate when compared to PI-RADS v1. Multiparametric MRI is accurate at detecting anterior tumours with a sensitivity of 86–88%.

     

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

IntroductionThis 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.MethodsThe 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.ResultsThe 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.     

The value of magnetic resonance imaging-ultrasound fusion targeted biopsies for clinical decision-making among patients with previously negative transrectal ultrasound biopsy and persistent prostate-specific antigen elevation

IntroductionTargeted biopsy approaches have been shown to increase the detection of clinically significant prostate cancer (csPCa) within index prostate lesions. We report our initial experience with magnetic resonance imaging-ultrasound fusion biopsies (MRI-TB) in a population of men who had a previously negative transrectal ultrasound (TRUS) biopsy, persistent prostate-specific antigen (PSA) elevation, and ongoing suspicion of PCa. Patients were followed prospectively to assess for changes in clinical management following targeted biopsy.MethodsWe prospectively followed the first 122 patients undergoing MRI-TB at our institution. All men had clinical suspicion of PCa, prior negative TRUS biopsies, and persistent PSA elevation. A total of 177 index lesions were identified on multiparametric MRI and reviewed using the Prostate Imaging Reporting and Data System (PI-RADS) v2 scoring system. Lesions classified as PI-RADS ≥3 received targeted biopsy. Biopsy-naive patients and those on active surveillance were excluded. The primary outcome was detection rate of csPCa, defined as International Society of Urological Pathology (ISUP) Grade Group (GG) ≥2. Multivariate analysis was used to determine predictors of csPCa on fusion biopsy.ResultsPrior to fusion biopsy, patients had a mean of 17.9±8.6 negative core biopsies per patient and a median PSA of 9.5 (standard deviation [SD] 6.2) ng/nl. MRI-TB resulted in diagnosis of csPCa in 42/122 (34.4%) patients. Clinically significant PCa was found in eight (13.1%), 14 (21.9%), and 25 (48.1%) of PI-RADS 3, 4, and 5 lesions, respectively. The location of csPCa was within the peripheral zone (55.3%), transitional zone (40.4%), and central zone (8.5%). Clinical outcomes of patients with newly diagnosed csPCa show 4.8%, 57.1%, and 38.1% receiving active surveillance, radiation treatment, and radical prostatectomy, respectively. Predictors for csPCa were presence of PI-RADS 5 lesions, age, length of time from MRI to biopsy, and smaller prostate volumes.ConclusionsMRI-TB yields high detection rates for csPCa in men with elusive PSA elevation and frequently guides a change in clinical management. Clinical decision-making based on MRI findings and PI-RADS lesion scores are best informed by an understanding of institutional reporting patterns.     

The effect of delaying transperineal fusion biopsy of the prostate for patients with suspicious MRI findings—Implications for the COVID-19 era

ObjectiveImage guided biopsies are an integral part of prostate cancer evaluation. The effect of delaying biopsies of suspicious prostate mpMRI lesions is uncertain and clinically relevant during the COVID-19 crisis.We evaluated the association between biopsy delay time and pathologic findings on subsequent prostate biopsy.Materials and methodsAfter obtaining IRB approval we reviewed the medical records of 214 patients who underwent image-guided transperineal fusion biopsy of the prostate biopsy between 2017 and 2019.Study outcomes included clinically significant (ISUP grade group ≥2) and any prostate cancer on biopsy. Logistic regression was used to evaluate the association between biopsy delay time and outcomes while adjusting for known predictors of cancer on biopsy.ResultsThe study cohort included 195 men with a median age of 68. Median delay between mpMRI and biopsy was 5 months, and 90% of patients had a ≤8 months delay. A significant association was found between PI-RADS 5 lesions and no previous biopsies and shorter delay time.Delay time was not associated with clinically significant or any cancer on biopsy. A higher risk of significant cancer was associated with older age (P = 0.008), higher PSA (0.003), smaller prostate volume (<0.001), no previous biopsy (0.012) and PI-RADS 5 lesions (0.015).ConclusionsOur findings suggest that under current practice, where men with PI-RADS 5 lesions and no previous biopsies undergo earlier evaluation, a delay of up to 8 months between imaging and biopsy does not affect biopsy findings.In the current COVID-19 crisis, selectively delaying image-guided prostate biopsies is unlikely to result in a higher rate of significant cancer.     

Which men with non-malignant pathology at magnetic resonance imaging-targeted prostate biopsy and persistent PI-RADS 3-5 lesions should repeat biopsy?

PurposeTo assess predictors of clinically significant (cs) prostate cancer (PCa) in men who had a non-malignant Multiparametric magnetic resonance imaging (mpMRI)-targeted biopsy and persistent Prostate Imaging-Reporting Data System (PI-RADS) 3 to 5 lesions in subsequent mpMRI.Materials and MethodsWe retrospectively analyzed MRI-targeted biopsy database in three centers. Inclusion criteria: persistence of at least one PI-RADS ≥3 lesion found negative for cancer in a previous MRI-targeted plus systemic biopsy (baseline biopsy). Exclusion criteria: downgrading to PI-RADS 1-2. A logistic regression analysis was performed to estimate the predictors of csPCa.ResultsFifty-seven patients were included. Median interval between biopsies was 12.9(2.43) months. Median age was 68.0(12) years. Median PSA was 7.0(5.45) ng/ml. At follow-up, 24.6%, 54.4%, and 21% of patients had a PI-RADS score 3, 4, and 5 index lesion (IL), respectively. At re-biopsy, 28/57(49.1%) men were found to harbor PCa. Among these, 22(78.6%) had csPCa. csPCa was found outside the IL in only 2 patients. Eleven, 13, and 5 patients with PI-RADS 3, 4, and 5, respectively, had no cancer. Three patients with a PI-RADS 3 lesion had cancer (2 with Gleason score 3+3, 1 with Gleason score 3+4). 14/43 men with a PI-RADS 4/5 lesion harbored Gleason score ≥3+4 PCa. Logistic regression analysis found that PSA (HR 1.281, 95% CI: 1.013–1.619, P = 0.039) and IL size (HR 1.146, 95% CI: 1.018–1.268, P = 0.041) were the predictors of csPCa at re-biopsy.ConclusionsPatients with non-malignant pathology from PI-RADS ≥3 lesions targeted biopsy should be follow-up with mpMRI, and those with persistent PI-RADS 4 to 5 lesions should repeat MRI-targeted and systematic biopsy.     

Multiparametric magnetic resonance imaging for prostate cancer—a comparative study including radical prostatectomy specimens

Purpose

To evaluate the diagnostic and staging ability of multiparametric MRI (mpMRI) compared to radical prostatectomy (RP) specimens after dissemination of this technology to several centres. mpMRI is an evolving technique aiming to improve upon the diagnostic sensitivity of prostate biopsy for the diagnosis of prostate cancer. Differences in interpretation, expertise and application of mpMRI are responsible for the range of reported results.

Methods

This retrospective clinical study was conducted with consecutive patients through an electronic database of tertiary hospitals and adjacent private urology practices in Australia. Patients having undergone RP were assessed for the presence of a pre-operative mpMRI performed between 2013 and 2015 which was evaluated against the reference standard of the RP whole-mount specimen. MRI reports were evaluated using the Prostate Imaging Reporting and Data System (PI-RADS).

Results

In our cohort of 152 patients, the sensitivity and specificity of mpMRI (PI-RADS ≥ 4) for prostate cancer (Gleason ≥ 4 + 3) detection were 83 and 47%, respectively. For the identification of extraprostatic disease, the sensitivity and specificity were 29 and 94%, respectively.

Conclusion

These results represent a ‘real-world’ approach to mpMRI and appear comparable to other single-centre studies. MRI staging information should be interpreted in context with other risk factors for extraprostatic disease. mpMRI has a useful role as an adjunct for prostate cancer diagnosis and directing management towards improving patient outcomes.

     

Clinical utility of MR/ultrasound fusion-guided biopsy in patients with lower suspicion lesions on active surveillance for low-risk prostate cancer

BackgroundThe utility of Multiparametric magnetic resonance imaging (mpMRI) guided prostate biopsy among patients with prostate cancer (CaP) managed with active surveillance (AS) with low-suspicion lesions remains unsettled.MethodsWe performed a retrospective analysis of 415 men with low-risk CaP managed with active surveillance. We selected men with mpMRI visible index lesions scored as 2 or 3 according to Prostate Imaging Reporting and Data System (PI-RADS) version 2. The primary outcome was detection of clinically significant prostate cancer (csCaP) was defined as Gleason grade group ≥ 2. We assessed the diagnostic accuracy of biopsy approaches using area under the receiver operator characteristic (ROC) curve and evaluated factors associated with csCaP in these patients using multivariate logistic regression.ResultsCsCaP was identified in 22 of 125 patients (17.6%) with PI-RADS 2 or 3 index lesions during surveillance prostate biopsies. These included 10 (45.5%) diagnosed by systematic biopsy alone, 9 (40.9%) by targeted alone, and 3 (13.6%) by both approaches. On multivariable analysis, the only significant variable predicting the detection of csCaP in men with low-risk imaging mpMRI characteristics was higher PSAD (OR per 0.1 unit=2.26, 95% CI 1.25–4.06, P = 0.007. A PSAD cutoff of 0.1, 0.12 and 0.15 resulted in a negative predictive value (NPV) of 90.9%, 87.1% and 86.2%, respectively. When stratified by PI-RADS score, a PSAD cutoff of 0.1, 0.12 and 0.15 resulted in NPV of 96.2%, 90.6% and 89.7% and 86.2%, 84.2% and 83.3% for detection of csCaP in PI-RADS 2 and 3 lesions, respectively. In patients with PIRDAS 2 lesions, using a PSAD of 0.1 would potentially allow 51% of patients to avoid biopsy with only a 3.8% chance of missing csCaP.ConclusionIn men with clinical low-risk prostate cancer on active surveillance with PI-RADS 2 and 3 lesions, there is an almost 18% risk of upgrade to csCaP. Integration of PSAD may be a useful adjunctive tool in identifying patients at highest risk for upgrade despite favorable imaging findings. In men with PIRADS 2 lesions with PSAD ≤0.12 biopsy can be avoided. For men with PIRADS 2 lesions with PSAD ≤0.15 informed decision making regarding the AS intensity should include that these patients have a low risk (>10%) of developing csCaP. In men with PIRADS 3 lesions with PSAD >0.1, shared decision making should include discussion of a >10% miss rate of csCaP.     

Histomorphological analysis of false positive PI-RADS 4 and 5 lesions

IntroductionMultiparametric magnetic resonance imaging (mpMRI)/ultrasound fusion-guided biopsy, in short “targeted biopsy (TB)”, is becoming more attractive as it improves the detection of clinically significant prostate cancer (CaP). The accuracy of fusion-guided biopsies is limited due to false positive radiological findings as well as to histological evidence for cancer in radiologically inconspicuous regions of the prostate. We aimed to analyze histomorphological findings on mpMRI lesions highly suspicious for CaP classified as PI-RADS 4 or PI-RADS 5 (Prostate Imaging - Recording and Data System) but cancer-negative in the biopsy of this region of interest (ROI), and to compare them with findings in radiologically inconspicuous regions.Materials and methodsWe re-evaluated prostate biopsies from 57 patients who underwent TB in combination with systematic standard biopsy (SB) from June 2017 to July 2018 at the University Hospital Schleswig Holstein Campus Luebeck. Out of 143 ROIs, 34 PI-RADS 4/5 cancer-negative lesions were identified and subjected to comprehensive histomorphological reevaluation. Contralateral cancer-negative SBs were used as control. Chi-square test was used for statistical analysis.ResultsThe frequency of histomorphological alterations including stromal, glandular, vascular, and inflammatory alterations were 97% and 79.2% in prostatic tissues from cancer-negative TBs and SBs, respectively. Stromal, glandular, and inflammatory alterations were present in the majority of biopsies from both TBs and SBs. Statistical analysis revealed no significant difference between TBs and SBs with regard to stromal, glandular, and inflammatory alterations. However, vascular abnormalities were exclusively detected in TBs (18.2%).ConclusionThe frequency of histomorphological alterations is slightly higher in prostate tissues from TBs compared to SB. Only vascular alterations seem to be distinct for TBs. However, it has to be assumed that additional factors influence the false-negative rate of mpMRI/ultrasound fusion-guided TB.     

Determining the diagnostic value of PSMA-PET/CT imaging in patients with persistent high prostate specific antigen levels and negative prostate biopsies

PurposeTo assess the diagnostic performance of prostate specific membranous antigen (PSMA) positron emission tomography/computed tomography (PET/CT) imaging to localize primary prostate cancer (PCa) in men with persistent elevated prostate-specific antigen (PSA) levels and previous prostate biopsies that were negative for PCa.MethodsIn this study, 34 men with persistently elevated PSA-levels, previous negative for PCa biopsies and who subsequently underwent diagnostic PSMA-PET/CT imaging were retrospectively evaluated. Men were divided into 3 groups: 1. 12 men with a previous negative mpMRI scan (PI-RADS 1-2) 2. 17 men with a positive mpMRI scan (PI-RADS 3-5), but negative MRI-targeted biopsies and 3. Four men in whom mpMRI was contraindicated. If PSMA-avid lesions were seen, patients underwent 2-4 cognitive targeted biopsies in combination with systematic biopsies. The detection rate of PSMA-PET/CT for PCa, and the accuracy of (possible) targeted biopsies were calculated.ResultsIncluded men had a median PSA-level of 22.8 ng/mL (Interquartile Range 15.6–30.0) at the time of PSMA-PET/CT. Elevated PSMA-ligand uptake in the prostate suspicious for PCa was observed in 22/34 patients (64.7%). In 18/22 patients (54.5%), PSMA-targeted prostate biopsies were performed. In 3/18 patients (16.6%), the targeted biopsies showed International Society of Urological Pathology (ISUP) score 1–2 PCa. The other men had inflammation or benign findings after histopathological examination of the biopsy cores.ConclusionIn this study, the clinical value of PSMA-PET/CT for patients with an elevated PSA-level, and negative for PCa biopsies was low. Only very few men were diagnosed with PCa, and no clinically significant PCa was found.