Posterior subcapsular prostate cancer: identification with mpMRI and MRI/TRUS fusion-guided biopsy

Predictors of Extraprostatic Extension in Patients with Prostate Cancer

PURPOSE

To identify effective factors predicting extraprostatic extension (EPE) in patients with prostate cancer (PCa).

METHODS

This retrospective cohort study recruited 898 consecutive patients with PCa treated with robot-assisted laparoscopic radical prostatectomy. The patients were divided into EPE and non-EPE groups based on the analysis of whole-mount histopathologic sections. Histopathological analysis (ISUP biopsy grade group) and magnetic resonance imaging (MRI) (PI-RADS v2.1 scores [1-5] and the Mehralivand EPE grade [0-3]) were used to assess the prediction of EPE. We also assessed the clinical usefulness of the prediction model based on decision-curve analysis.

RESULTS

Of 800 included patients, 235 (29.3%) had EPE, and 565 patients (70.7%) did not (non-EPE). Multivariable logistic regression analysis showed that the biopsy ISUP grade, PI-RADS v2.1 score, and Mehralivand EPE grade were independent risk factors for EPE. In the regression assessment of the models, the best discrimination (area under the curve of 0.879) was obtained using the basic model (age, serum PSA, prostate volume at MRI, positive biopsy core, clinical T stage, and D'Amico risk group) and Mehralivand EPE grade 3. Decision-curve analysis showed that combining Mehralivand EPE grade 3 with the basic model resulted in superior net benefits for predicting EPE.

CONCLUSION

Mehralivand EPE grades and PI-RADS v2.1 scores, in addition to basic clinical and demographic information, are potentially useful for predicting EPE in patients with PCa.

[Prostate Imaging Reporting and Data System (PI-RADS) v 2.1: Overview and Critical Points]

The technical parameters and imaging interpretation criteria of the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) using multiparametric MRI (mpMRI) are updated in PI-RADS v2.1. These changes have been an expected improvement for prostate cancer evaluation, although some issues remain unsolved, and new issues have been raised. In this review, a brief overview of PI-RADS v2.1 is and several critical points are discussed as follows: the need for more detailed protocols of mpMRI, lack of validation of the revised transition zone interpretation criteria, the need for clarification for the revised diffusion-weighted imaging and dynamic contrast-enhanced imaging criteria, anterior fibromuscular stroma and central zone assessment, assessment of background signal and tumor aggressiveness, changes in the structured report, the need for the parameters for imaging quality and performance control, and indications for expansion of the system to include other indications.

MRI determined prostate volume and the incidence of prostate cancer on MRI-fusion biopsy: a systemic review of reported data for the last 20 years

PURPOSE

Magnetic resonance imaging (MRI) is a precise, systemic and advantageous imaging technique when compared to transrectal ultrasound (TRUS) which is very operator dependent. The negative correlation between prostate volume and the incidence of prostate cancer (PCa) obtained by TRUS biopsy has been well documented in the literature. The purpose of this systemic review is analyzing the reported MRI-fusion study results on prostate biopsies regarding any correlation between prostate volume and the incidence of PCa.

METHODS

After defining the inclusion and exclusion criteria an in-depth review were performed between 01.01.2000 and 02.08.2022 using the PubMed database and applying the "PRISMA" guidelines.

RESULTS

Twelve studies qualified, and all showed an inverse/negative relationship between prostate volume and incidence of PCa. Sample sizes ranged from 33 to 2767 patients in single and multi-institutional studies. All studies showed a statistically significant inverse relationship with a p value < 0.05. The graph summarizing all of studies and using Fisher's method revealed a highly significant combined p level of 0.00001. Additionally, not one single study was found showing the contrary (a positive correlation between prostate size and the incidence of PCa).

CONCLUSION

To our knowledge, this is the first systemic review of reported MRI-Fusion data on the incidence of PCa in correlation with prostate volume. This MRI review confirms previous TRUS-biopsy studies which demonstrated an inverse relationship between prostate volume and the incidence of PCa, and thus further supports the hypothesis that large prostates size may be protective against PCa when compared to smaller prostates.

MRI/Transrectal Ultrasound Fusion-Guided Targeted Biopsy and Transrectal Ultrasound-Guided Systematic Biopsy for Diagnosis of Prostate Cancer: A Systematic Review and Meta-analysis

Purpose

For men suspected of having prostate cancer (PCa), the transrectal ultrasound (TRUS)-guided systematic biopsy (SB) was performed. MRI/TRUS fusion guided-targeted biopsy (MRI-TB) could enhance PCa detection, allowing sampling of sites at higher risk which were not obvious with TRUS alone. The aim of this systematic review and meta-analysis was to compare the detection rates of prostate cancer by MRI-TB or MRI-TB plus SB versus SB, mainly for diagnosis of high-risk PCa.

Methods

A literature Search was performed on PubMed, Cochrane Library, and Embase databases. We searched from inception of the databases up to January 2021.

Results

A total of 5831 patients from 26 studies were included in the present meta-analysis. Compared to traditional TRUS-guided biopsy, MRI-TB had a significantly higher detection rate of clinically significant PCa (RR=1.27; 95%CI 1.15-1.40; p<0.001) and high-risk PCa (RR=1.41; 95% CI 1.22-1.64; p<0.001), while the detection rate of clinically insignificant PCa was lower (RR=0.65; 95%CI 0.55-0.77; p<0.001). MRI-TB and SB did not significantly differ in the detection of overall prostate cancer (RR=1.04; 95%CI 0.95-1.12; p=0.41). Compared with SB alone, we found that MRI-TB plus SB diagnosed more cases of overall, clinically significant and high-risk PCa (p<0.001).

Conclusion

Compared with systematic protocols, MRI-TB detects more clinically significant and high-risk PCa cases, and fewer clinically insignificant PCa cases. MRI-TB combined with SB enhances PCa detection in contrast with either alone but did not reduce the diagnosis rate of clinically insignificant PCa.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#searchadvanced, CRD42021218475.

Comparison of diagnostic performance and inter-reader agreement between PI-RADS v2.1 and PI-RADS v2: systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis comparing diagnostic performance and inter reader agreement between PI-RADS v. 2.1 and PI-RADS v. 2 in the detection of clinically significant prostate cancer (csPCa).

METHODS

A systematic review was performed, searching the major biomedical databases (Medline, Embase, Scopus), using the keywords "PIRADS 2.1" or "PI RADS 2.1" or "PI-RADS 2.1". Studies reporting on head-to-head diagnostic comparison between PI-RADS v. 2.1 and v. 2 were included. Pooled sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were compared between PI-RADS v. 2.1 and v. 2. Summary receiver operator characteristic graphs were plotted. Analysis was performed for whole gland, and pre-planned subgroup analysis was performed by tumour location (whole gland vs transition zone (TZ)), high b-value DWI (b-value ≥1400 s/mm2), and reader experience (<5 years vs ≥5 years with prostate MRI interpretation). Inter-reader agreement and pooled rates of csPCa for PI-RADS 1-3 lesions were compared between PI-RADS v. 2.1 and v. 2. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool v. 2 (QUADAS-2).

RESULTS

Eight studies (1836 patients, 1921 lesions) were included. Pooled specificity for PI-RADS v. 2.1 was significantly lower than PI-RADS v. 2 for whole gland (0.62 vs 0.66, p = 0.02). Pooled sensitivities, PPVs and NPVs were not significantly different (p = 0.17, 0.31, 0.41). Pooled specificity for PI-RADS v. 2.1 was significantly lower than PI-RADS v. 2 for TZ only (0.67 vs 0.72, p = 0.01). Pooled sensitivities, PPVs and NPVs were not significantly different (p = 0.06, 0.36, 0.17). Amongst studies utilising diffusion-weighted imaging with highest b-value of ≥1400 s/mm2, pooled sensitivities, specificities, PPVs and NPVs were not significantly different (p = 0.52, 0.4, 0.5, 0.47). There were no significant differences in pooled sensitivities, specificities, PPVs and NPVs between PI-RADS v. 2.1 and PI-RADS v. 2 for less-experienced readers (p = 0.65, 0.37, 0.65, 0.81) and for more experienced readers (p = 0.57, 0.90, 0.91, 0.65). For PI-RADS v. 2.1 alone, there were no significant differences in pooled sensitivity, specificity, PPV and NPV between less and more experienced readers (p = 0.38, 0.70, 1, 0.48). Inter-reader agreement was moderate to substantial for both PI-RADS v. 2.1 and v. 2. There were no significant differences between pooled csPCa rates between PI-RADS v. 2.1 and v. 2 for PI-RADS 1-2 lesions (6.6% vs  7.3%, p = 0.53), or PI-RADS 3 lesions (24.1% vs  26.8%, p = 0.28).

CONCLUSIONS

Diagnostic performance and inter-reader agreement for PI-RADS v. 2.1 is comparable to PI-RADS v. 2, however the significantly lower specificity of PI-RADS v. 2.1 may result in increased number of unnecessary biopsies.

ADVANCES IN KNOWLEDGE

1. Compared to PI-RADS v. 2, PI-RADS v. 2.1 has a non-significantly higher sensitivity but a significantly lower specificity for detection of clinically significant prostate cancer.2. PI-RADS v. 2.1 could potentially result in considerable increase in number of negative targeted biopsy rates for PI-RADS 3 lesions, which could have been potentially avoided.

PI-RADS Version 2.1: A Critical Review, From the AJR Special Series on Radiology Reporting and Data Systems

PI-RADS version 2.1 updates the technical parameters for multiparametric MRI (mpMRI) of the prostate and revises the imaging interpretation criteria while maintaining the framework introduced in version 2. These changes have been considered an improvement, although some issues remain unresolved, and new issues have emerged. Areas for improvement discussed in this review include the need for more detailed mpMRI protocols with optimization for 1.5-T and 3-T systems; lack of validation of revised transition zone interpretation criteria and need for clarifications of the revised DWI and dynamic contrast-enhanced imaging criteria and central zone (CZ) assessment; the need for systematic evaluation and reporting of background changes in signal intensity in the prostate that can negatively affect cancer detection; creation of a new category for lesions that do not fit into the PI-RADS assessment categories (i.e., PI-RADS M category); inclusion of quantitative parameters beyond size to evaluate lesion aggressiveness; adjustments to the structured report template, including standardized assessment of the risk of extraprostatic extension; development of parameters for image quality and performance control; and suggestions for expansion of the system to other indications (e.g., active surveillance and recurrence).

Apical periurethral transition zone lesions: MRI and histology findings

PURPOSE

Apical periurethral transition zone (TZ) cancers can pose unique problems for surgery and radiation therapy. Here, we describe the appearance of such cancers on multiparametric MRI (mpMRI) and correlate this with histopathology derived from MRI-targeted biopsy.

MATERIALS AND METHODS

Between May 2011 and January 2019, a total of 4381 consecutive patients underwent 3 T mpMRI. Of these, 53 patients with 58 apical periurethral TZ lesions underwent TRUS/MRI fusion-guided biopsy and 12-core systematic TRUS-guided biopsy. Correlation was made with patient age, PSA, PSA density, whole prostate volume, and Gleason scores.

RESULTS

A total 53 men (median age 68 years, median PSA 7.94 ng/ml) were identified as having at least one apical periurethral TZ lesion on mpMRI and 5 (9%) patients had more than one apical periurethral lesion. Thus, 58 lesions were identified in 53 patients. Of these 37/53 patients (69%) and 40/58 lesions were positive at biopsy for prostate cancer. Seven were diagnosed by 12-core systematic TRUS-guided biopsy and 34 were diagnosed by TRUS/MRI fusion-guided biopsy. Gleason score was ≥ 3 + 4 in 34/58 (58%) lesions.

CONCLUSION

Identification of apical periurethral TZ prostate cancers is important to help guide surgical and radiation therapy as these tumors are adjacent to critical structures. Because of the tendency to undersample the periurethral zone during TRUS biopsy, MRI-guided biopsy is particularly helpful for detecting apical periurethral TZ prostate cancers many of which prove to be clinically significant.

Integration of spatial information in convolutional neural networks for automatic segmentation of intraoperative transrectal ultrasound images

Image guidance systems that register scans of the prostate obtained using transrectal ultrasound (TRUS) and magnetic resonance imaging are becoming increasingly popular as a means of enabling tumor-targeted prostate cancer biopsy and treatment. However, intraoperative segmentation of TRUS images to define the three-dimensional (3-D) geometry of the prostate remains a necessary task in existing guidance systems, which often require significant manual interaction and are subject to interoperator variability. Therefore, automating this step would lead to more acceptable clinical workflows and greater standardization between different operators and hospitals. In this work, a convolutional neural network (CNN) for automatically segmenting the prostate in two-dimensional (2-D) TRUS slices of a 3-D TRUS volume was developed and tested. The network was designed to be able to incorporate 3-D spatial information by taking one or more TRUS slices neighboring each slice to be segmented as input, in addition to these slices. The accuracy of the CNN was evaluated on data from a cohort of 109 patients who had undergone TRUS-guided targeted biopsy, (a total of 4034 2-D slices). The segmentation accuracy was measured by calculating 2-D and 3-D Dice similarity coefficients, on the 2-D images and corresponding 3-D volumes, respectively, as well as the 2-D boundary distances, using a 10-fold patient-level cross-validation experiment. However, incorporating neighboring slices did not improve the segmentation performance in five out of six experiment results, which include varying the number of neighboring slices from 1 to 3 at either side. The up-sampling shortcuts reduced the overall training time of the network, 161 min compared with 253 min without the architectural addition.

Incidental findings on multiparametric MRI performed for evaluation of prostate cancer

PURPOSE

Multiparametric magnetic resonance imaging (mp-MRI) and MRI/Ultrasound (US) fusion-guided biopsy are relatively new techniques for improved detection, staging, and active surveillance of prostate cancer (PCa). As with all imaging modalities, MRI reveals incidental findings (IFs) which carry the risk of increased cost, patient anxiety, and iatrogenic morbidity due to workup of IFs. Herein, we report the IFs from 684 MRIs for evaluation of PCa and consider their characteristics and clinical significance.

METHODS

Patients underwent mp-MRI prostate protocol incorporating triplanar T2-weighted, diffusion-weighted, and dynamic contrast-enhanced pelvic MRI as well as a post-contrast abdominopelvic MRI with the primary indication of detection or evaluation of PCa. A total of 684 consecutive prostate MRI reports performed in a series of 580 patients were reviewed. All extraprostatic findings reported were logged and then categorized by organ system and potential clinical significance.

RESULTS

There were 349 true IFs found in 233 (40%) of the 580 patients. One hundred nineteen additional extraprostatic findings were unsuspected but directly related to PCa staging, while the 349 IFs were unrelated and thus truly incidental beyond study indication. While the majority of true IFs were non-urologic, only 6.6% of IFs were considered clinically significant, non-urologic findings, and more than a third of MRI reports had urologic IFs not related to PCa.

CONCLUSIONS

Rates of incidental findings on prostate indication MRI are similar to other abdominopelvic imaging studies. However, only 6.6% of the IFs were considered to be clinically significant non-urologic findings. Further investigations are needed to assess downstream workup of these IFs and resulting costs.

Multimodality Image Fusion with PSMA PET/CT and High-Intensity Focused Ultrasound Focal Therapy for Primary Diagnosis and Management of Prostate Cancer: A Planned Research Initiative

Recent developments in diagnostic imaging herald a new approach to diagnosis and management of prostate cancer. Multimodality fusion that combines anatomic with functional imaging data has surpassed either of the two alone. This opens up the possibility to "find and fix" malignancy with greater accuracy than ever before. This is particularly important for prostate cancer because it is the most common male cancer in most developed countries. This article describes technical advances under investigation at our institution and others using multimodality image fusion of magnetic resonance imaging (MRI), transrectal ultrasound (TRUS), and PSMA PET/CT (defined as the combination of prostate-specific membrane antigen [PSMA], positron emission tomography [PET], and computed tomography [CT]) for personalized medicine in the diagnosis and focal therapy of prostate cancer with high-intensity focused ultrasound (HiFUS).

The prostate cancer prevention trial risk calculator 2.0 performs equally for standard biopsy and MRI/US fusion-guided biopsy

BACKGROUND

The Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPTRC) is a widely used risk-based calculator used to assess a man's risk of prostate cancer (PCa) before biopsy. This risk calculator was created from data of a patient cohort undergoing a 6-core sextant biopsy, and subsequently validated in men undergoing 12-core systematic biopsy (SBx). The accuracy of the PCPTRC has not been studied in patients undergoing magnetic resonance imaging/ultrasound (MRI/US) fusion-guided biopsy (FBx). We sought to assess the performance of the PCPTRC for straitifying PCa risk in a FBx cohort.

METHODS

A review of a prospective cohort undergoing MRI and FBx/SBx was conducted. Data from consecutive FBx/SBx were collected between August 2007 and February 2014, and PCPTRC scores using the PCPTRC2.0R-code were calculated. The risk of positive biopsy and high-grade cancer (Gleason ⩾7) on biopsy was calculated and compared with overall and high-grade cancer detection rates (CDRs). Receiver operating characteristic curves were generated and the areas under the curves (AUCs) were compared using DeLong's test.

RESULTS

Of 595 men included in the study, PCa was detected in 39% (232) by SBx compared with 48% (287) on combined FBx/SBx biopsy. The PCPTRC AUCs for the CDR were similar (P=0.70) for SBx (0.69) and combined biopsy (0.70). For high-grade disease, AUCs for SBx (0.71) and combined biopsy (0.70) were slightly higher, but were not statistically different (P=0.55).

CONCLUSIONS

In an MRI-screened population of men undergoing FBx, PCPTRC continues to represent a practical method of accurately stratifying PCa risk.

Molecular imaging and fusion targeted biopsy of the prostate

PURPOSE

This paper provides a review on molecular imaging with positron emission tomography (PET) and magnetic resonance imaging (MRI) for prostate cancer detection and its applications in fusion targeted biopsy of the prostate.

METHODS

Literature search was performed through the PubMed database using the keywords "prostate cancer", "MRI/ultrasound fusion", "molecular imaging", and "targeted biopsy". Estimates in autopsy studies indicate that 50% of men older than 50 years of age have prostate cancer. Systematic transrectal ultrasound (TRUS) guided prostate biopsy is considered the standard method for prostate cancer detection and has a significant sampling error and a low sensitivity. Molecular imaging technology and new biopsy approaches are emerging to improve the detection of prostate cancer.

RESULTS

Molecular imaging with PET and MRI shows promising results in the early detection of prostate cancer. MRI/TRUS fusion targeted biopsy has become a new clinical standard for the diagnosis of prostate cancer. PET molecular image-directed, three-dimensional ultrasound-guided biopsy is a new technology that has great potential for improving prostate cancer detection rate and for distinguishing aggressive prostate cancer from indolent disease.

CONCLUSION

Molecular imaging and fusion targeted biopsy are active research areas in prostate cancer research.

Should Hypoechoic Lesions on Transrectal Ultrasound Be Sampled During Magnetic Resonance Imaging-targeted Prostate Biopsy?

OBJECTIVE

To determine whether supplemental biopsy of hypoechoic ultrasound lesions (HUL) incidentally found during magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion-targeted prostate biopsy results in improved prostate cancer (PCa) detection.

METHODS

Patients underwent MRI-TRUS-targeted biopsy as part of an ongoing prospective trial from August 2007 to February 2015. For men with HUL, the biopsy pathology of HUL and MRI lesions was classified according to the updated 2014 International Society of Urological Pathology (ISUP) grading system. The detection of PCa by MRI-targeted biopsy with and without HUL biopsy was compared.

RESULTS

Of 1260 men in the trial, 106 underwent biopsy of 119 HULs. PCa was diagnosed in 52 out of 106 men (49%) by biopsy of either MRI lesions or HUL. Biopsy of HUL in addition to MRI lesions resulted in 4 additional diagnoses of high-grade (ISUP grades 3-5) PCa versus biopsy of MRI lesions alone (20 vs 16 men, P = .046). Three of these cases were upgraded from lower grade (ISUP grades 1-2) PCa on MRI-guided biopsy alone, and only 1 case (1% of cohort) was diagnosed that would have been missed by MRI-guided biopsy alone. Supplemental biopsy of HUL did not change the PCa risk category in 96% (102 out of 106) of men with HUL.

CONCLUSION

Supplemental biopsy of HUL yields a small increase in the detection of higher grade PCa as compared with biopsy of MRI lesions alone. As upgrading is rare, routinely screening for HUL during MRI-targeted biopsy remains controversial.

Comparison of image quality and patient discomfort in prostate MRI: pelvic phased array coil vs. endorectal coil

PURPOSE

To compare image quality (IQ) and patient discomfort during prostate MRI using a pelvic phased array (PPA) coil and an endorectal (ER) coil.

MATERIALS AND METHODS

Ninety-eight patients (median age, 65.7; range 42.1-78.1) underwent prostate MRI on a 3T scanner including T2w and DWI acquired with PPA and an ER coil within the same exam. Acquisition time was kept similar for both acquisitions. Two radiologists evaluated aspects of IQ on a 5-point Likert scale and classified image artifacts. All patients completed a questionnaire on discomfort/pain regarding the ER coil using a visual analogue scale from 1 to 10.

RESULTS

There was no significant difference in overall IQ for T2w images for both readers (reader 1, 3.27 ± 0.91 and 3.07 ± 0.84, p = 0.057; reader 2, 3.70 ± 0.75 and 3.77 ± 0.81, p = 0.555) for PPA and ER coils, respectively. Overall IQ for DWI acquired with PPA and ER coils was rated similar by reader 1 (3.03 ± 1.10 and 3.08 ± 0.80, respectively, (p = 0.67)), while reader 2 preferred ER coil images (3.27 ± 0.81 and 3.66 ± 0.85 (p < 0.05)). Susceptibility artifacts were more frequent in ER than in PPA coil images (109 vs. 75). Discomfort and pain experienced during insertion of the ER coil was low altogether (VAS score, 3.5 ± 2.1 for "discomfort" and 2.4 ± 2.4 for "pain").

CONCLUSION

T2-weighted images may be acquired with comparable IQ using a PPA coil as compared to an ER coil, while DWI images showed better IQ using the ER coil for one of two readers. The insertion of the ER coil caused low to moderate discomfort and pain in patients.

Integration of multiparametric MRI into active surveillance of prostate cancer

Prostate cancer is the most common noncutaneous cancer in men though many men will not die of this disease and may not require definitive treatment. Active surveillance (AS) is an increasingly utilized potential solution to the issue of overtreatment of prostate cancer. Traditionally, prostate cancer patients have been stratified into risk groups based on clinical stage on digital rectal examination, prostate-specific antigen and biopsy Gleason score, though each of these variables has significant limitations. This review will discuss the potential role for prostate multiparametric MRI and targeted biopsy techniques incorporating MRI in the selection of candidates for AS, monitoring patients on AS and as triggers for definitive treatment.

Magnetic Resonance Imaging-Ultrasound Fusion-Guided Prostate Biopsy: Review of Technology, Techniques, and Outcomes

Transrectal ultrasound (TRUS)-guided (12-14 core) systematic biopsy of the prostate is the recommended standard for patients with suspicion of prostate cancer (PCa). Advances in imaging have led to the application of magnetic resonance imaging (MRI) for the detection of PCa with subsequent development of software-based co-registration allowing for the integration of MRI with real-time TRUS during prostate biopsy. A number of fusion-guided methods and platforms are now commercially available with common elements in image and analysis and planning. Implementation of fusion-guided prostate biopsy has now been proven to improve the detection of clinically significant PCa in appropriately selected patients.

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

PURPOSE

Multiparametric magnetic resonance imaging and fusion biopsy detect more high risk prostate cancer and less low risk prostate cancer than systematic biopsy. However, there remains a small subset of patients in whom systematic biopsy captures higher grade disease than fusion biopsy. We sought to identify potential mechanisms of the failure of fusion biopsy in the detection of clinically significant prostate cancer.

MATERIALS AND METHODS

We reviewed a prospectively maintained database of patients who underwent multiparametric magnetic resonance imaging followed by fusion biopsy and systematic biopsy from 2007 to 2014. In patients in whom disease was upgraded to clinically significant disease (Gleason 7 or greater) by systematic biopsy over fusion biopsy, independent re-review of magnetic resonance imaging, archived biopsy imaging and whole mount pathology as well as needle coordinate mapping were performed. Multivariate logistic regression analysis was done to determine predictors of upgrading by systematic biopsy.

RESULTS

Disease was upgraded based on systematic biopsy over fusion biopsy in 135 of 1,003 patients (13.5%), of whom only 62 (6.2%) were upgraded to intermediate (Gleason 7) and high risk (Gleason 8 or greater) prostate cancer (51 or 5.1% and 11 or 1.1%, respectively). On multivariate analysis lower prostate specific antigen (p <0.001), higher magnetic resonance imaging prostate volume (p <0.001) and a lower number of target cores (p = 0.001) were predictors of upgrading by systematic biopsy. Main mechanisms of under grading by fusion biopsy included multiparametric magnetic resonance imaging reader oversight, presence of magnetic resonance imaging invisible cancer, fusion biopsy technique error and intralesion Gleason heterogeneity.

CONCLUSIONS

Magnetic resonance imaging and fusion biopsy rarely missed clinically significant prostate cancer as only 62 of 1,003 cases (6.2%) were upgraded to clinically significant disease by systematic biopsy. Imaging and biopsy techniques are continually refined. Further studies will help clarify mechanisms of fusion biopsy failure and the patient populations that benefit from systematic biopsy in addition to fusion biopsy.

Tumor contact with prostate capsule on magnetic resonance imaging: A potential biomarker for staging and prognosis

BACKGROUND

The high-spatial resolution of multiparametric magnetic resonance imaging (mpMRI) has improved the detection of clinically significant prostate cancer. mpMRI characteristics (extraprostatic extension [EPE], number of lesions, etc.) may predict final pathological findings (positive lymph node [pLN] and pathological ECE [pECE]) and biochemical recurrence (BCR). Tumor contact length (TCL) on MRI, defined as the length of a lesion in contact with the prostatic capsule, is a novel marker with promising early results. We aimed to evaluate TCL as a predictor of +pathological EPE (+pEPE),+pathological LN (+pLN), and BCR in patients undergoing robotic-assisted laparoscopic radical prostatectomy.

MATERIALS AND METHODS

A review was performed of a prospectively maintained single-institution database of men with prostate cancer who underwent prostate mpMRI followed by robotic-assisted laparoscopic radical prostatectomy without prior therapy from 2007 to 2015. TCL was measured using T2-weighted magnetic resonance images. Logistic and Cox regression analysis were used to assess associations of clinical, imaging, and histopathological variables with pEPE, pLN, and BCR. Receiver operating characteristic curves were used to characterize and compare TCL performance with Partin tables.

RESULTS

There were 87/379 (23.0%)+pEPE, 18/384 (4.7%)+pLN, and 33/371 (8.9%) BCR patients. Patients with adverse pathology/oncologic outcomes had longer TCL compared to those without adverse outcomes (+pEPE: 19.8 vs. 10.1mm, P<0.0001,+pLN: 38.0 vs. 11.7mm, P<0.0001, and BCR: 19.2 vs. 11.2mm, P = 0.001). On multivariate analysis, TCL remained a predictor of+pEPE (odds ratio: 1.04, P = 0.001),+pLN (odds ratio: 1.07, P<0.0001), and BCR (hazard ratio: 1.03, P = 0.02). TCL thresholds for predicting+pEPE and+pLN were 12.5 and 19.7mm, respectively. TCL alone was found to have good predictive ability for+pEPE and+PLN (pEPE:TCL_AUC: 0.71 vs. Partin_AUC: 0.66, P = 0.21; pLN:TCL_AUC: 0.77 vs. Partin_AUC: 0.88, P = 0.04).

CONCLUSION

We demonstrate that TCL is an independent predictor of+pEPE, +pLN, and BCR. If validated, this imaging biomarker may facilitate and inform patient counseling and decision-making.

Magnetic resonance imaging - ultrasound fusion targeted biopsy outperforms standard approaches in detecting prostate cancer: A meta-analysis

The aim of the present study was to determine whether magnetic resonance imaging - ultrasound (MRI-US) fusion prostate biopsy is superior to systematic biopsy for making a definitive diagnosis of prostate cancer. The two strategies were also compared regarding their ability to detect clinically significant and insignificant prostate cancer. A literature search was conducted through the PubMed, EMBASE and China National Knowledge Infrastructure databases using appropriate search terms. A total of 3,415 cases from 21 studies were included in the present meta-analysis. Data were expressed as relative risk (RR) and 95% confidence interval. The results revealed that MRI-US fusion biopsy achieved a higher rate of overall prostate cancer detection compared with systematic biopsy (RR=1.09; P=0.047). Moreover, MRI-US fusion biopsy detected more clinically significant cancers compared with systematic biopsy (RR=1.22; P<0.01). It is therefore recommended that multi-parametric MRI-US is performed in men suspected of having prostate cancer to optimize the detection of clinically significant disease, while reducing the burden of biopsies.

Risk stratification of prostate cancer: integrating multiparametric MRI, nomograms and biomarkers

Accurate risk stratification of prostate cancer is achieved with a number of existing tools to ensure the identification of at-risk patients, characterization of disease aggressiveness, prediction of cancer burden and extrapolation of treatment outcomes for appropriate management of the disease. Statistical tables and nomograms using classic clinicopathological variables have long been the standard of care. However, the introduction of multiparametric MRI, along with fusion-guided targeted prostate biopsy and novel biomarkers, are being assimilated into clinical practice. The majority of studies to date present the outcomes of each in isolation. The current review offers a critical and objective assessment regarding the integration of multiparametric MRI and fusion-guided prostate biopsy with novel biomarkers and predictive nomograms in contemporary clinical practice.

Multiparametric prostate magnetic resonance imaging in the evaluation of prostate cancer

Imaging has traditionally played a minor role in the diagnosis and staging of prostate cancer. However, recent controversies generated by the use of prostate-specific antigen (PSA) screening followed by random biopsy have encouraged the development of new imaging methods for prostate cancer. Multiparametric magnetic resonance imaging (mpMRI) has emerged as the imaging method best able to detect clinically significant prostate cancers and to guide biopsies. Here, the authors explain what mpMRI is and how it is used clinically, especially with regard to high-risk populations, and we discuss the impact of mpMRI on treatment decisions for men with prostate cancer. CA Cancer J Clin 2016;66:326-336. © 2015 American Cancer Society.

Midline lesions of the prostate: role of MRI/TRUS fusion biopsy and implications in Gleason risk stratification

PURPOSE

MRI-TRUS fusion biopsy (FBx) has proven efficacy in targeting suspicious areas that are traditionally missed by systematic 12-core biopsy (SBx). Midline prostate lesions are undersampled during SBx, as traditional approaches aim laterally during TRUS biopsy. The aim of our study was to determine the utility of FBx for targeting midline lesions identified on multiparametric MRI (mpMRI).

METHODS

A review was performed of a prospectively maintained database of patients undergoing mpMRI followed by FBx and SBx from 2007 to 2015. Midline location was defined as any lesion crossing the midline on axial imaging and involving both prostatic lobes. Index lesion was defined as lesion with highest Gleason score on biopsy. Patient demographic, imaging, and histopathologic data were collected. Multivariate logistic regression was conducted to determine independent predictors of having clinically significant (CS) cancer (Gleason ≥ 7) in midline lesions.

RESULTS

Out of 1266 patients, we identified 202 suspicious midline lesions in 190 patients [median (IQR) age 63 (10) years; PSA 7.6 (6.6)]. Eighty-eight (46.3 %) patients had cancer detection on FBx of midline lesion. A midline target represented the index lesion of the prostate in 63/190 (33.2 %) patients. Risk category upgrading based on FBx of a midline lesion compared to SBx occurred in 45/190 patients (23.7 %). On multivariate analysis, higher PSA (p = .001), lower MRI-derived prostate volume (p < .001), and moderate-high or high suspicion on mpMRI (p = .014) predicted CS cancer in midline lesions.

CONCLUSIONS

MRI-TRUS FBx facilitates sampling of midline lesions. Integration of mpMRI and FBx for targeting of midline lesions improves detection of CS prostate cancer.

A urologist's perspective on prostate cancer imaging: past, present, and future

Prostate cancer is unique in that unlike other solid organ malignancies, only recently has imaging been employed to routinely detect and localize disease. The introduction of transrectal ultrasound was a significant development, transitioning digitally guided prostate biopsies to ultrasound guidance. The arrival of multiparametric MRI has become the next major step, transforming the way Urologist's diagnose, stage, and treat prostate cancer. Recent recommendations against PSA screening have changed the landscape of urologic oncology with the changing needs being reflected in the initiation of additional robust imaging techniques at different time points in prostate cancer care. The current review aims to provide a clinical perspective in the history, current standard of care, and novel imaging modalities in the evaluation of prostate cancer.

Optimizing Patient Population for MP-MRI and Fusion Biopsy for Prostate Cancer Detection

The diagnosis and treatment of prostate cancer continue to evolve with advances in science and technology. The utilization of multiparametric MRI (mp-MRI) to identify lesions in the prostate has given clinicians the ability to visualize malignancy in the prostate with greater confidence. With this new ability came the advancement of fusion biopsy platforms, which allow for direct targeting of these lesions. As with any new technology in medicine, the proper use of these modalities and how they fit into current clinical practice need to be addressed. This review summarizes the current knowledge on how to best optimize which men undergo mp-MRI and fusion biopsies both in the screening and treatment settings.

The significance of anterior prostate lesions on multiparametric magnetic resonance imaging in African-American men

INTRODUCTION

African-American (AA) men tend to harbor high-risk prostate cancer (PCa) and exhibit worse outcomes when compared to other groups. It has been postulated that AA men may harbor more anterior prostate lesions (APLs) that are undersampled by the standard transrectal ultrasound guided-biopsy (SBx), potentially resulting in greater degree of Gleason score (GS) upgrading at radical prostatectomy. We aimed to evaluate the detection rate of anterior PCa significance of APLs in AA men on multiparametric magnetic resonance imaging (mpMRI) and compare it to a matched cohort of White/Other (W/O) men.

MATERIALS AND METHODS

A review of 1,267 men who had an mpMRI with suspicious prostate lesions and who underwent magnetic resonance transrectal ultrasound fusion-guided biopsy (FBx) with concurrent SBx in the same biopsy session was performed. All AA men were matched to a control group of W/O using a 1:1 propensity score-matching algorithm with age, prostate-specific antigen, and prostate volume as matching variables. Logistic regression analysis was used to determine predictors of APLs in AA men.

RESULTS

Of the 195 AA men who underwent mpMRI, 93 (47.7%) men had a total of 109 APLs. Prior negative SBx was associated with the presence of APLs in AA men (Odds ratio = 1.81; 95% CI: 1.03-3.20; P = 0.04). On multivariate logistic regression analysis, smaller prostate (P = 0.001) and rising prostate-specific antigen (P = 0.007) were independent predictors of cancer-positive APLs in AA men. Comparative analysis of AA (93/195, 47.7%) vs. W/O (100/194, 52%) showed no difference in the rates of APLs (P = 0.44) or in cancer detection rate within those lesions or the distribution of GS within those cancers (P = 0.63) despite an overall higher cancer detection rate in AA men (AA: 124/195 [63.6%] vs. W/O: 97/194 [50.0%], P = 0.007). In cases where APLs were positive for PCa on FBx, the GS of APL was equal to the highest GS of the entire gland in 82.9% (29/35) and 90.9% (30/33) of the time in AA and W/O men, respectively.

CONCLUSION

Cancer-positive APLs represented the highest risk GS in most cases. AA men with prior negative SBx are twice as likely to harbor a concerning APL. In our cohort, AA and W/O men had comparable rates of APLs on mpMRI. Thus, differences in APLs do not explain the higher risk of AA men for deahth due to PCa. However, targeting of APLs via FBx can clinically improve PCa risk stratification and guide appropriate treatment options.

Prostate Cancer Diagnosis on Repeat Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy of Benign Lesions: Recommendations for Repeat Sampling

PURPOSE

Urologists face a dilemma when a lesion identified on multiparametric magnetic resonance imaging is benign on image guided fusion biopsy. We investigated the detection rate of prostate cancer on repeat fusion biopsy in multiparametric magnetic resonance imaging lesions initially found to be pathologically benign on fusion biopsy.

MATERIALS AND METHODS

We reviewed the records of all patients from 2007 to 2014 who underwent multiparametric magnetic resonance imaging and image guided fusion biopsy. We identified men who underwent rebiopsy of the same discrete lesion after initial fusion biopsy results were benign. Data were documented on a per lesion basis. We manually reviewed UroNav system (Invivo, Gainesville, Florida) needle tracking to verify accurate image registration. Multivariate analysis was used to identify clinical and imaging factors predictive of prostate cancer detection at repeat fusion biopsy.

RESULTS

A total of 131 unique lesions were rebiopsied in 90 patients. Of these 131 resampled lesions 21 (16%) showed prostate cancer, which in 13 (61.9%) was Gleason 3 + 3. On multivariate analysis only lesion growth on repeat multiparametric magnetic resonance imaging was significantly associated with prostate cancer detection at repeat biopsy (HR 3.274, 95% CI 1.205-8.896, p = 0.02).

CONCLUSIONS

Pathologically benign multiparametric magnetic resonance imaging lesions on initial image guided fusion biopsy are rarely found to harbor clinically significant prostate cancer on repeat biopsy. When prostate cancer was identified, most disease was low risk. An increase in lesion diameter was an independent predictor of prostate cancer detection. While these data are retrospective, they may provide some confidence in the reliability of negative initial image guided fusion biopsies despite a positive multiparametric magnetic resonance imaging finding.

Evaluating the Role of mpMRI in Prostate Cancer Assessment

Prostate cancer is the most common malignancy among American men. The role of multi-parametric MRI has recently gained more importance in detection of prostate cancer, its targeted biopsy, and focal therapy guidance. In this review, uses of multi-parametric MRI in prostate cancer assessment and treatment are discussed.

Reproducibility of Multiparametric Magnetic Resonance Imaging and Fusion Guided Prostate Biopsy: Multi-Institutional External Validation by a Propensity Score Matched Cohort

PURPOSE

As the adoption of magnetic resonance imaging/ultrasound fusion guided biopsy expands, the reproducibility of outcomes at expert centers becomes essential. We sought to validate the comprehensive NCI (National Cancer Institute) experience with multiparametric magnetic resonance imaging and fusion guided biopsy in an external, independent, matched cohort of patients.

MATERIALS AND METHODS

We compared 620 patients enrolled in a prospective trial comparing systematic biopsy to fusion guided biopsy at NCI to 310 who underwent a similar procedure at Long Island Jewish Medical Center. The propensity score, defined as the probability of being treated outside NCI, was calculated using the estimated logistic regression model. Patients from the hospital were matched 1:1 for age, prostate specific antigen, magnetic resonance imaging suspicion score and prior negative biopsies. Clinically significant disease was defined as Gleason 3 + 4 or greater.

RESULTS

Before matching we found differences between the cohorts in age, magnetic resonance imaging suspicion score (each p <0.001), the number of patients with prior negative biopsies (p = 0.01), and the overall cancer detection rate and the cancer detection rate by fusion guided biopsy (each p <0.001). No difference was found in the rates of upgrading by fusion guided biopsy (p = 0.28) or upgrading to clinically significant disease (p = 0.95). A statistically significant difference remained in the overall cancer detection rate and the rate by fusion guided biopsy after matching. On subgroup analysis we found a difference in the overall cancer detection rate and the rate by fusion guided biopsy (p <0.001 and 0.003) in patients with prior negative systematic biopsy but no difference in the 2 rates (p = 0.39 and 0.51, respectively) in biopsy naïve patients.

CONCLUSIONS

Improved detection of clinically significant cancer by magnetic resonance imaging and fusion guided biopsy is reproducible by an experienced multidisciplinary team consisting of dedicated radiologists and urologists.