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.     

Multiparametric Magnetic Resonance Imaging for the Detection of Clinically Significant Prostate Cancer: What Urologists Need to Know. Part 3: Targeted Biopsy

BackgroundAfter a lesion has been assessed adequately on multiparametric magnetic resonance imaging (mpMRI), magnetic resonance (MR)-guided biopsy (MRGB) is the logical next step. The choice of the MRGB technique, however, is difficult.ObjectiveTo show the advantages and disadvantages of the three commonly used MRGB techniques—MRI-ultrasound fusion MRGB (fus-MRGB), direct in-bore MRGB (inbore-MRGB), and cognitive MRGB (cog-MRGB), and to determine when each of the techniques can be used.Design, setting, and participantsBased on expert opinion and literature overview, the advantages, disadvantages, and challenges of fus-MRGB, inbore-MRGB, and cog-MRGB are evaluated. Further, the clinical setting of each biopsy strategy is assessed.Surgical procedureBased on expert opinion and literature data, the three biopsy procedures are evaluated, and the important pros and cons are determined.MeasurementsThe basic concept of each biopsy technique is reviewed, which would result in a clinical recommendation. This will be shown in individual patients.Results and limitationsThe accompanying video shows how fus-MRGB and inbore-MRGB are performed in our hospital. An important advantage of fus-MRGB is its generally availability; however, it has fusion-error limitations. Although not supported by evidence, inbore-MRGB seems to be better suited for smaller lesions, but is rather expensive. Cog-MRGB is easy to use and inexpensive, but is more operator dependent as it requires knowledge about both ultrasound and MR images. Readers should be aware that our MRGB approach is largely based on expert opinion and, where possible, supported by evidence.ConclusionsThis article and the accompanying video show different MRGB techniques. The advantages and disadvantages of the three biopsy techniques, as well as the clinical setting in which each biopsy strategy is being used in our hospital, are discussed. Fus-MRGB is our first choice for prostate biopsy. Direct inbore-MRGB is used in difficult lesions but is mainly used as a “problem solver” (eg, a negative biopsy with a high suspicion for clinically significant prostate cancer). In our opinion, cog-MRGB is best for sampling larger and diffuse lesions.Patient summaryThis third surgery in motion contribution shows our approach in magnetic resonance (MR)-guided biopsy (MRGB). Fusion MRGB is our first choice for prostate biopsy. In-bore MRGB is used in selected, difficult cases, mainly as a problem solver. In our point of view, cognitive MRGB seems to be best for sampling larger lesions and diffuse processes.     

Multiparametric Magnetic Resonance Imaging for the Detection of Clinically Significant Prostate Cancer: What Urologists Need to Know. Part 1: Acquisition

BackgroundAcquiring multiparametric magnetic resonance images of the prostate is not a simple “push-button” approach.ObjectiveTo show how image acquisition of prostate multiparametric Magnetic Resonance Imaging (mpMRI) can be optimized.Design, setting, and participantsImage protocols, magnetic field strength choice, and the use of receiver coils are discussed. In addition, patient preparation and the recognition, prevention, and mitigation of artifacts are evaluated.Surgical procedureBased on expert prostate MRI technologists (MRI radiographers) opinion, the optimal protocol is reviewed, and potential artifacts are determined.MeasurementsThe entire acquisition process is presented from initial patient preparation until the end of the imaging. The choice of the used equipment, pulse sequences, and prevention of patient- and imaging-related artifacts are presented. This will be shown in individual patients.Results and limitationsAlthough the Prostate Imaging Reporting and Data System guidelines (2012 and 2016) describe minimal and optimal acquisition protocols for prostate mpMRI, these standards are not always met in daily practice. A major challenge in mpMRI is to obtain high image quality and reduce its variability for radiologic interpretations. A summary of evidence and guidelines for the acquisition of mpMRI of the prostate can set a basic guideline to reduce these variabilities.ConclusionsThis article and an accompanying video can be used as a guide by MRI technologists (MRI radiographers) to improve their image acquisitions by optimizing protocols, magnetic field strength choice, and use of receiver coils. We also discuss patient preparation and the recognition, prevention, and mitigation of artifacts.Patient summaryIn this first surgery-in-motion contribution, we will show how optimized image acquisition is performed to detect prostate cancer. Both MRI-dependent and patient related factors are discussed.     

Combination of Diffusion-weighted Magnetic Resonance Imaging and Extended Prostate Biopsy Predicts Lobes Without Significant Cancer: Application in Patient Selection for Hemiablative Focal Therapy

Background

Significant cancer in contralateral sides of the prostate that was missed on prostate biopsy (PBx) is a concern in hemiablative focal therapy (FT) of prostate cancer (PCa). However, extended PBx, a common diagnostic procedure, has a limited predictive ability for lobes without significant cancer.

Objective

To identify prostate lobes without significant cancer using extended PBx combined with diffusion-weighted imaging (DWI), which has the potential to provide pathophysiologic information on pretreatment assessment.

Design, setting, and participants

We conducted a prebiopsy DWI study between 2007 and 2012 that included 270 prostate lobes in 135 patients who underwent radical prostatectomy (RP) for clinically localized PCa.

Intervention

Participants underwent DWI and 14-core PBx; those with PBx-proven PCa and who were treated with RP were analyzed.

Outcome measurements and statistical analysis

Imaging and pathology were assessed in each side. Based on RP pathology, lobes were classified into lobes with no cancer (LNC), lobes with indolent cancer (LIC), and lobes with significant cancer (LSC). Predictive performance of DWI, PBx, and their combination in identifying lobes without significant cancer was examined.

Results and limitations

LNC, LIC, and LSC were identified in 23 (8.5%), 64 (23.7%), and 183 sides (67.8%), respectively. The negative predictive values (NPV) of DWI, PBx, and their combination were 22.1%, 27.8%, and 43.5%, respectively, for lobes with any cancer (ie, either LIC or LSC), and 68.4%, 72.2%, and 95.7%, respectively, for LSC. The NPV of PBx for LSC was improved by the addition of DWI findings (p = 0.001), with no adverse influence on the positive predictive value. Limitations included a possible selection bias under which the decision to perform PBx might be affected by DWI findings.

Conclusions

The combination of DWI and extended PBx efficiently predicts lobes without significant cancer. This procedure is applicable to patient selection for hemiablative FT.     

Technical Refinements in Superextended Robot-assisted Radical Prostatectomy for Locally Advanced Prostate Cancer Patients at Multiparametric Magnetic Resonance Imaging

BackgroundThe feasibility and efficacy of robot-assisted radical prostatectomy (RARP) in locally advanced prostate cancer (PCa) patients with iT3 lesion at magnetic resonance imaging (MRI) are currently not explored.ObjectiveTo describe our revised RARP technique (ie, superextended RARP [SE-RARP]) for PCa patients with posterior iT3a or iT3b at MRI.Design, setting, and participantsData from 89 patients with posterior iT3a or T3b disease who underwent SE-RARP at a single high-volume centre between 2015 and 2018 were analysed.Surgical procedureRARP was performed using a DaVinci Xi system. The surgical approach provided an inter- or extrafascial RARP where Denonvilliers’ fascia and perirectal fat were dissected free and left on the posterior surface of the seminal vesicles.MeasurementsPerioperative outcomes, and intra- and postoperative complications were assessed. Postoperative outcomes were assessed in patients with complete follow-up data (n = 78). Biochemical recurrence (BCR) was defined as two consecutive prostate-specific antigen values of ≥0.2 ng/ml. Urinary continence (UC) recovery was defined as the use of zero or one safety pad. Kaplan-Meier and multivariable Cox regression models were used.Results and limitationsThe median operative time, blood loss, and length of stay were 204 min, 300 ml, and 5 d, respectively. The median bladder catheterisation time was 5 d. Overall, 28%, 28%, and 27% of patients had pathological grade group (GG) 4–5, pT3b, and positive surgical margins (PSMs), respectively. Three patients (3.4%) experienced intraoperative complications. Among patients with available follow-up data (n = 78), 14 (18%) experienced 30-d postoperative complications. The median follow-up was 19 mo. Overall, 11 patients received additional treatment. At 2 yr of follow-up, BCR-free and additional treatment–free survival were 55% and 66%, respectively. Pathological GG 4–5 (hazard ratio [HR] 3.2) and PSM (HR 5.8) were independent predictors of recurrence, as well as of additional treatment use (HR 5.6 for GG 4–5 and 5.2 for PSM). The 1-yr UC recovery was 84%.ConclusionsWe presented our revised RARP technique applicable to patients with posterior iT3a or iT3b at preoperative MRI. This technique is associated with good morbidity and continence recovery rates, and might guarantee biochemical control of the disease and postpone the use of additional treatments in patients with low-grade and negative surgical margins.Patient summaryA revised robot-assisted radical prostatectomy technique applicable to prostate cancer patients with posterior iT3a or iT3b lesion at magnetic resonance imaging was described. This novel technique is feasible and safe in expert hands.     

Head-to-head Comparison of Transrectal Ultrasound-guided Prostate Biopsy Versus Multiparametric Prostate Resonance Imaging with Subsequent Magnetic Resonance-guided Biopsy in Biopsy-naïve Men with Elevated Prostate-specific Antigen: A Large Prospective Multicenter Clinical Study

Background

There is growing interest to implement multiparametric magnetic resonance imaging (mpMRI) and MR-guided biopsy (MRGB) for biopsy-naïve men with suspected prostate cancer.

Optimising the Diagnosis of Prostate Cancer in the Era of Multiparametric Magnetic Resonance Imaging: A Cost-effectiveness Analysis Based on the Prostate MR Imaging Study (PROMIS)

Background

The current recommendation of using transrectal ultrasound-guided biopsy (TRUSB) to diagnose prostate cancer misses clinically significant (CS) cancers. More sensitive biopsies (eg, template prostate mapping biopsy [TPMB]) are too resource intensive for routine use, and there is little evidence on multiparametric magnetic resonance imaging (MPMRI).

Multiparametric Magnetic Resonance Imaging as a Noninvasive Assessment of Tumor Response to Neoadjuvant Pembrolizumab in Muscle-invasive Bladder Cancer: Preliminary Findings from the PURE-01 Study

BackgroundIn the PURE-01 study, pembrolizumab was given preoperatively before radical cystectomy in clinical T2-4aN0M0 patients. An accurate clinical response assessment may be useful for developing new perioperative strategies in these patients.ObjectiveTo evaluate the association between bladder multiparametric magnetic resonance imaging (mpMRI) findings after pembrolizumab and the pathological complete response (CR; pT0).Design, setting, and participantsPatients were staged using bladder mpMRI whereby radiologists were asked to characterize the following parameters: residual disease at T1- and T2-weighted images (step 1: yes/no), presence of hyperintense spots within the bladder wall on diffusion-weighted imaging (step 2: yes/no), and presence of pathological contrast enhancement (step 3: yes/no), before and after three cycles of pembrolizumab. Examinations were internally assessed by two senior radiologists and externally evaluated by a third senior radiologist.InterventionTo evaluate bladder tumor response after neoadjuvant pembrolizumab, mpMRI was used.Outcome measurements and statistical analysisThe primary objective was to predict the pT0 after neoadjuvant pembrolizumab by relying on the mpMRI findings. Cohen’s kappa statistics was used to assess interobserver variability. Univariable analyses for pT0 were performed including internal and external post-therapy mpMRI steps.Results and limitationsFrom February 2017 to October 2018, 82 patients (164 total mpMRI assessments) were analyzed. The agreement between the internal and external mpMRI assessments after therapy was acceptable (κ values ranging from 0.5 to 0.76). Each mpMRI step was significantly associated with pT0 in both internal and external assessments. In patients with CR/no evidence of residual disease (NED) in all internally evaluated mpMRI steps (N = 37), the pT0 was seen in 23 (62%), compared with 19 of 26 externally evaluated NED patients (73%).ConclusionsIn post-pembrolizumab muscle-invasive bladder cancer, mpMRI sequence assessment had acceptable interobserver variability and represented the basis for the proposal of a radiological CR/NED status definition predicting the pT0 response to pembrolizumab. After validation of these findings with external datasets, we propose this tool for developing bladder-sparing immunotherapy maintenance therapies.Patient summaryAssessment of the extent of disease in patients with muscle-invasive bladder cancer using conventional imaging yields serious limitations. In the PURE-01 study, we evaluated the potential of bladder multiparametric magnetic resonance imaging (MRI) to predict the pathological complete response to neoadjuvant pembrolizumab. After validation with larger datasets, the proposed stepwise assessment incorporating multiparametric MRI sequences will be used at our center to develop bladder-sparing approaches in future studies.     

Prediction of High-grade Prostate Cancer Following Multiparametric Magnetic Resonance Imaging: Improving the Rotterdam European Randomized Study of Screening for Prostate Cancer Risk Calculators

Background

The Rotterdam European Randomized Study of Screening for Prostate Cancer risk calculators (ERSPC-RCs) help to avoid unnecessary transrectal ultrasound-guided systematic biopsies (TRUS-Bx). Multivariable risk stratification could also avoid unnecessary biopsies following multiparametric magnetic resonance imaging (mpMRI).

Functional Magnetic Resonance Imaging in Prostate Cancer

Context

Magnetic resonance imaging (MRI) combined with magnetic resonance spectroscopy imaging (MRSI), dynamic contrast-enhanced MRI, and diffusion-weighted MRI emerged as promising tests in the diagnosis of prostate cancer, and they show encouraging results.

Objective

This review emphasizes different functional MRI techniques in the diagnosis of prostate cancer and includes information about their clinical value and usefulness.

Evidence acquisition

The authors searched the Medline, Embase, and Cochrane Library databases. There were no language restrictions. The last search was performed in October 2008.

Evidence synthesis

The combination of conventional MRI with functional MRI techniques is more reliable for differentiating benign and malignant prostate tissues than any other diagnostic procedure. At present, no guideline is available that outlines which technique is best in a specific clinical situation. It also remains uncertain whether improved spatial resolution and signal-to-noise ratio of 3-T MRI will improve diagnostic performance.

Conclusions

A limited number of small studies suggest that functional MRI may improve the diagnosis and staging of prostate cancer. This finding needs further confirmation in larger studies, and cost-effectiveness needs to be established.     

Diagnostic Performance of Magnetic Resonance Imaging for the Detection of Bone Metastasis in Prostate Cancer: A Systematic Review and Meta-analysis

Context

Magnetic resonance imaging (MRI) has been tested for detecting bone metastasis and has shown promising results. Yet, consensus has not been reached regarding whether it can replace the role of bone scintigraphy in this clinical setting or not.