Imaging Assessment of Prostate Cancer Extra-prostatic Extension: From Histology to Controversies

Prostate cancer (PCa) is the most common non-skin malignancy among men and the fourth leading cause of cancer-related deaths globally. Accurate staging of PCa, particularly the assessment of extra-prostatic extension (EPE), is critical for prognosis and treatment planning. EPE, typically evaluated using magnetic resonance imaging (MRI), is associated with higher risks of positive surgical margins, biochemical recurrence, metastasis, and reduced overall survival. Despite the widespread use of MRI, there is no consensus on diagnosing EPE via imaging. There are 2 main scores assessing EPE by MRI: the European Society of Urogenital Radiology score and an MRI-based EPE grading system from an American group. While both are widely recognized, their differences can lead to varying interpretations in specific cases. This paper clarifies the anatomical considerations in diagnosing locally advanced PCa, explores EPE's impact on treatment and prognosis, and evaluates the relevance of MRI findings according to different criteria. Accurate EPE diagnosis remains challenging due to MRI limitations and inconsistencies in interpretation. Understanding these variations is crucial for optimal patient management.

A comparative analysis of techniques for measuring tumor contact length in predicting extraprostatic extension

PURPOSE

This study aims to evaluate the diagnostic performance of curvilinear and linear measurement methods in different magnetic resonance imaging (MRI) sequences for detecting extraprostatic extension (EPE) in prostate cancer, and to evaluate the added value of apparent diffusion coefficient (ADC) in detecting EPE.

METHODS

A retrospective analysis was conducted on 84 patients who underwent multiparametric MRI (mp-MRI) prior to radical prostatectomy between January 2019 and February 2022. Tumor contact length (TCL) was assessed curvilinearly and linearly on T2-weighted imaging (T2WI), ADC maps, and dynamic contrast-enhanced (DCE) MRI by two radiologists. MRI-based EPE positivity was defined as a curvilinear or linear contact length of >15 mm. Statistical comparisons were conducted using chi-squared and independent samples t-tests, with interreader agreement evaluated using weighted κ statistics. Univariate and multivariate logistic regression identified independent predictors of EPE, and two prediction models were constructed. Diagnostic performance was assessed using receiver operator characteristic (ROC) curve analysis.

RESULTS

A total of 32 (38%) and 52 (62%) patients with EPE and non-EPE, respectively, were included in this study. Patients with EPE demonstrated significantly larger tumor sizes, lower ADC values, and lower ADC ratios than those without EPE (p < 0.001). The curvilinear and linear TCL measurements for each sequence exhibited statistically significant correlations with EPE for both readers, with strong interreader agreement. Curvilinear TCL (c-TCL) and linear TCL (l-TCL) on DCE-MRI showed higher area under the curve (AUC) values than the other measurements for EPE prediction (reader 1: 0.815 and 0.803, reader 2: 0.746 and 0.713, respectively). However, there was no statistically significant difference between c-TCL and l-TCL. Multivariable models with mean ADC value improved predictive performance. Model 2 (ADC, ISUP, and c-TCL on DCE images) surpassed model 1 (ADC and c-TCL on DCE images) with an AUC of 0.919 and 0.874, respectively.

CONCLUSION

DCE-MRI demonstrated superior performance in predicting EPE compared to other sequences. Linear and curvilinear measurements had comparable diagnostic performance. Being more practical and easier, radiologists may use l-TCL measurement in daily practice. The mean ADC value provided additional diagnostic value.

Extra-prostatic extension grading system: correlation with MRI features and integration of capsular enhancement sign for "enhanced" detection of T3a lesions

PURPOSE

This study aims to confirm the diagnostic accuracy of extra-prostatic extension (EPE) grading system and to explore the predictive capabilities of the prostate MRI while considering various MRI features such as lesion location, apparent diffusion coefficient (ADC) values and capsular enhancement sign (CES).

METHODS

Our monocentric study is based on a retrospective analysis of 99 patients who underwent radical prostatectomy from January 2021 to January 2023. The observers reviewed for each lesion, including location (transitional or peripheral zone, anterior or posterior location), capsular contact length, irregular bulging of the capsule, asymmetry of the neurovascular bundle, obliteration of the recto-prostatic angle, macroscopic EPE, ADC value, and CES.

RESULTS

Among 99 patients, 31 patients had EPE. Lesions with EPE have broadercapsule contact (24 mm vs 12 mm) with contact ≥14 mm being the optimal cut-off for EPE discrimination. Among the morphological MRI criteria used to determine the EPE, the one with major sensitivity was shown to be bulging (sen 81%), while macroscopic extension had highest specificity (100%). Univariate analysis showed as significative risk factors for EPE: capsular contact ≥14 mm (P < .001), International Society of Urological Pathology score ≥3 (P = .005), CES (P < .001), bulging (P = .001), neurovascular bundle asymmetry (P < .001) and EPE score ≥2 (P < .001), and in multivariate analysis CES (P = .001) and EPE score ≥2 (P = .004) were significant. The AUC of the EPE score was 0.76, raised to 0.83 when combining it with CES (P = .11).

CONCLUSION

CES in the setting of multiparametric MRI can increase diagnostic accuracy for the prediction of extracapsular disease.

ADVANCES IN KNOWLEDGE

This study highlights the potential of contrast media in prostate cancer local staging.

Amide proton transfer imaging has added value for predicting extraprostatic extension in prostate cancer patients

Background

Prostate cancer invades the capsule is a key factor in selecting appropriate treatment methods. Accurate preoperative prediction of extraprostatic extension (EPE) can help achieve precise selection of treatment plans.

Purpose

The aim of this study is to verify the diagnostic efficacy of tumor size, length of capsular contact (LCC), apparent diffusion coefficient (ADC), and Amide proton transfer (APT) value in predicting EPE. Additionally, the study aims to investigate the potential additional value of APT for predicting EPE.

Method

This study include 47 tumor organ confined patients (age, 64.16 ± 9.18) and 50 EPE patients (age, 61.51 ± 8.82). The difference of tumor size, LCC, ADC and APT value between groups were compared. Binary logistic regression was used to screen the EPE predictors. The receiver operator characteristic curve analysis was performed to assess the diagnostic performance of variables for predicting EPE. The diagnostic efficacy of combined models (model I: ADC+LCC+tumor size; model II: APT+LCC+tumor size; and model III: APT +ADC+LCC+tumor size) were also analyzed.

Results

APT, ADC, tumor size and the LCC were independent predictors of EPE. The area under the curve (AUC) of APT, ADC, tumor size and the LCC were 0.752, 0.665, 0.700 and 0.756, respectively. The AUC of model I, model II, and model III were 0.803, 0.845 and 0.869, respectively. The cutoff value of APT, ADC, tumor size and the LCC were 3.65%, 0.97×10-3mm2/s, 17.30mm and 10.78mm, respectively. The sensitivity/specificity of APT, ADC, tumor size and the LCC were 76%/89.4.0%, 80%/59.6%, 54%/78.9%, 72%/66%, respectively. The sensitivity/specificity of model I, Model II and Model III were 74%/72.3%, 82%/72.5% and 84%/80.9%, respectively.

Data conclusion

Amide proton transfer imaging has added value for predicting EPE. The combination model of APT balanced the sensitivity and specificity.

Quantitative MRI in the Local Staging of Prostate Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Local staging of prostate cancer (PCa) is important for treatment planning. Radiologist interpretation using qualitative criteria is variable with high specificity but low sensitivity. Quantitative methods may be useful in the diagnosis of extracapsular extension (ECE).

PURPOSE

To assess the performance of quantitative MRI markers for detecting ECE.

STUDY TYPE

Systematic review and meta-analysis.

SUBJECTS

4800 patients from 28 studies with histopathologically confirmed PCa on radical prostatectomy were pooled for meta-analysis. Patients from 46 studies were included for systematic review.

FIELD STRENGTH/SEQUENCE

Diffusion-weighted, T2-weighted, and dynamic contrast-enhanced MRI at 1.5 T or 3 T.

ASSESSMENT

PubMed, Embase, Web of Science, Scopus, and Cochrane databases were searched to identify studies on diagnostic test accuracy or association of any quantitative MRI markers with ECE. Results extracted by two independent reviewers for tumor contact length (TCL) and mean apparent diffusion coefficient (ADC-mean) were pooled for meta-analysis, but not for other quantitative markers including radiomics due to low number of studies available.

STATISTICAL TESTS

Hierarchical summary receiver operating characteristic (HSROC) curves were computed for both TCL and ADC-mean, but summary operating points were computed for TCL only. Heterogeneity was investigated by meta-regression. Results were significant if P ≤ 0.05.

RESULTS

At the 10 mm threshold for TCL, summary sensitivity and specificity were 0.76 [95% confidence interval (CI) 0.71-0.81] and 0.68 [95% CI 0.63-0.73], respectively. At the 15 mm threshold, summary sensitivity and specificity were 0.70 [95% CI 0.53-0.83] and 0.74 [95% CI 0.60-0.84] respectively. The area under the HSROC curves for TCL and ADC-mean were 0.79 and 0.78, respectively. Significant sources of heterogeneity for TCL included timing of MRI relative to biopsy.

DATA CONCLUSION

Both 10 mm and 15 mm thresholds for TCL may be reasonable for clinical use. From comparison of the HSROC curves, ADC-mean may be superior to TCL at higher sensitivities.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

Extraprostatic extension in multiparametric MRI; Is presurgical detection possible?

INTRODUCTION

Extraprostatic extension (EPE) is one of the important factors affecting the prognosis of prostate cancer (PCa). Therefore, preoperative evaluation of the presence of EPE is essential in multiparametric magnetic resonance imaging (mpMRI) examination. However, for the evaluation of mpMRI, objective criteria are needed to detect EPE, especially microscopic EPE.

AIM

To evaluate the efficacy of 1.5T MRI using lesion length (LL) and tumor-capsule contact length (TCL) in detecting EPE in PCa.

METHODS

A total of 110 patients who underwent radical prostatectomy due to PCa were enrolled. Preoperative MR images were evaluated retrospectively by two independent observers who did not know the histopathological results. The observers evaluated LL and TCL. The radiological findings, including lesion location, were verified using histopathological mapping.

RESULTS

Multiparametric MRI examination of the prostate demonstrated low sensitivity (Observer 1; 40.4% and Observer 2; 40.4%) but high specificity (Observer 1; 96.6% and Observer 2; 84.5%), with significant differences for detecting EPE (Observer 1, P < 0.0001; Observer 2, P = 0.003). The increased PI-RADS score correlated positively with the increased EPE rate (P < 0.0001 for both observers). The mean LL and TCL values were statistically significantly higher in patients with EPE than in patients without EPE. The TCL was a significant parameter for EPE, with high sensitivity and low for both observers. For both observes the cutoff value of LL for EPE was 14.5 mm, and the cutoff value of TCL for EPE was 9.5 mm. Histopathological LL value (28 ± 12,3 mm) was higher than radiological LLs (Observer 1; 22,14 ± 10,15 mm and Observer 2; 19,06 ± 8,61).

CONCLUSION

The results revealed that 1.5T MRI demonstrated low sensitivity and high specificity in detecting EPE. The LL and TCL may be indirectly beneficial in detecting EPE. Considering the radiological underestimation of LL may be helpful before PCa surgery.

Prostate-specific antigen level, biopsy grade group, and tumor-capsular contact length on magnetic resonance imaging are independently associated with an extraprostatic extension

OBJECTIVE

To define the clinicopathological and radiological factors independently associated with the existence of an extraprostatic extension in radical prostatectomy specimens.

METHODS

A total of 202 patients who underwent robotic prostatectomy following biparametric magnetic resonance imaging were assessed. We evaluated the clinicopathological and magnetic resonance imaging variables. We performed receiver-operating characteristic curve analyses to identify factors associated with extraprostatic extension. We engaged in multivariate analysis to identify factors independently associated with such extension.

RESULTS

Extraprostatic extensions were apparent in the final prostatectomy specimens of 62 patients (31%). The areas under the curves of the prostate-specific antigen level, the biopsy grade group, and the tumor-capsular contact length on magnetic resonance imaging were 0.76, 0.71, and 0.70, respectively, in receiver-operating characteristic analysis when used to predict extraprostatic extension; thus, higher than the areas under the curves of the other variables (0.61-0.68). The prostate-specific antigen level (odds ratio 1.090, p = 0.004), the biopsy grade group (odds ratios 2.678 and 6.358, p = 0.017 and p < 0.001 for grade group 3-4 and 5), and the tumor-capsular contact length (odds ratio 1.079, p = 0.001) were independently associated with extraprostatic extension. When the three factors were combined, the area under the receiver-operator characteristic curve increased to 0.79.

CONCLUSIONS

The prostate-specific antigen level, the biopsy grade group, and the tumor-capsular contact length on magnetic resonance imaging were independently associated with extracapsular extension.

Comparison of single-shot EPI and multi-shot EPI in prostate DWI at 3.0 T

In prostate MRI, single-shot EPI (ssEPI) DWI still suffers from distortion and blurring. Multi-shot EPI (msEPI) overcomes the drawbacks of ssEPI DWI. The aim of this article was to compare the image quality and diagnostic performance for clinically significant prostate cancer (csPC) between ssEPI DWI and msEPI DWI. This retrospective study included 134 patients with suspected PC who underwent 3.0 T MRI and subsequent MRI-guided biopsy. Three radiologists independently assessed anatomical distortion, prostate edge clarity, and lesion conspicuity score for pathologically confirmed csPC. Lesion apparent diffusion coefficient (ADC) and benign ADC were also calculated. In 17 PC patients who underwent prostatectomy, three radiologists independently assessed eight prostate regions by DWI score in PI-RADS v 2.1. Anatomical distortion and prostate edge clarity were significantly higher in msEPI DWI than in ssEPI DWI in the three readers. Lesion conspicuity score was significantly higher in msEPI DWI than in ssEPI DWI in reader 1 and reader 3. Regarding discrimination ability between PC with GS ≤ 3 + 4 and PC with GS ≥ 4 + 3 using lesion ADC, AUC was comparable between ssEPI DWI and msEPI DWI. For diagnostic performance of csPC using DWI score, AUC was comparable between msEPI DWI and ssEPI DWI in all readers. Compared with ssEPI DWI, msEPI DWI had improved image quality and similar or higher diagnostic performance.

Clinical application of single-shot echo-planar diffusion-weighted imaging with compressed SENSE in prostate MRI at 3T: preliminary experience

OBJECTIVES

Image quality (IQ) of diffusion-weighted imaging (DWI) with single-shot echo-planar imaging (ssEPI) suffers from low signal-to-noise ratio (SNR) in high b-value acquisitions. Compressed SENSE (C-SENSE), which combines SENSE with compressed sensing, enables SNR to be improved by reducing noise. The aim of this study was to compare IQ and prostate cancer (PC) detectability between DWI with ssEPI using SENSE (EPIS) and using C-SENSE (EPICS).

MATERIALS AND METHODS

Twenty-five patients with pathologically proven PC underwent multi-parametric magnetic resonance imaging at 3T. DW images acquired with EPIS and EPICS were assessed for the following: lesion conspicuity (LC), SNR, contrast-to-noise ratio (CNR), mean and standard deviation (SD) of apparent diffusion coefficient (ADC) of lesion (lADCm and lADCsd), coefficient of variation of lesion ADC (lADCcv), and mean ADC of benign prostate (bADCm).

RESULTS

LC were comparable between EPIS and EPICS (p > 0.050), and SNR and CNR were significantly higher in EPICS than EPIS (p = 0.001 and p < 0.001). In both EPIS and EPICS, lADCm was significantly lower than bADCm (p < 0.001). In addition, lADCcv was significantly lower in EPICS than in EPIS (p < 0.001).

CONCLUSION

Compared with EPIS, EPICS has improved IQ and comparable diagnostic performance in PC.

The role of MRI in prostate cancer: current and future directions

There has been an increasing role of magnetic resonance imaging (MRI) in the management of prostate cancer. MRI already plays an essential role in the detection and staging, with the introduction of functional MRI sequences. Recent advancements in radiomics and artificial intelligence are being tested to potentially improve detection, assessment of aggressiveness, and provide usefulness as a prognostic marker. MRI can improve pretreatment risk stratification and therefore selection of and follow-up of patients for active surveillance. MRI can also assist in guiding targeted biopsy, treatment planning and follow-up after treatment to assess local recurrence. MRI has gained importance in the evaluation of metastatic disease with emerging technology including whole-body MRI and integrated positron emission tomography/MRI, allowing for not only better detection but also quantification. The main goal of this article is to review the most recent advances on MRI in prostate cancer and provide insights into its potential clinical roles from the radiologist's perspective. In each of the sections, specific roles of MRI tailored to each clinical setting are discussed along with its strengths and weakness including already established material related to MRI and the introduction of recent advancements on MRI.

The Quantitative Assessment of Using Multiparametric MRI for Prediction of Extraprostatic Extension in Patients Undergoing Radical Prostatectomy: A Systematic Review and Meta-Analysis

PURPOSE

To investigate the diagnostic performance of using quantitative assessment with multiparametric MRI (mpMRI) for prediction of extraprostatic extension (EPE) in patients with prostate cancer (PCa).

METHODS

We performed a computerized search of MEDLINE, Embase, Cochrane Library, Web of Science, and Google Scholar from inception until July 31, 2021. Summary estimates of sensitivity and specificity were pooled with the bivariate model, and quality assessment of included studies was performed with the Quality Assessment of Diagnostic Accuracy Studies-2. We plotted forest plots to graphically present the results. Multiple subgroup analyses and meta-regression were performed to explore the variate clinical settings and heterogeneity.

RESULTS

A total of 23 studies with 3,931 participants were included. The pooled sensitivity and specificity for length of capsular contact (LCC) were 0.79 (95% CI 0.75-0.83) and 0.77 (95% CI 0.73-0.80), for apparent diffusion coefficient (ADC) were 0.71 (95% CI 0.50-0.86) and 0.71 (95% CI 059-0.81), for tumor size were 0.62 (95% CI 0.57-0.67) and 0.75 (95% CI 0.67-0.82), and for tumor volume were 0.77 (95% CI 0.68-0.84) and 0.72 (95% CI 0.56-0.83), respectively. Substantial heterogeneity was presented among included studies, and meta-regression showed that publication year (≤2017 vs. >2017) was the significant factor in studies using LCC as the quantitative assessment (P=0.02).

CONCLUSION

Four quantitative assessments of LCC, ADC, tumor size, and tumor volume showed moderate to high diagnostic performance of predicting EPE. However, the optimal cutoff threshold varied widely among studies and needs further investigation to establish.

Diffusion-weighted imaging in prostate cancer

Diffusion-weighted imaging (DWI), a key component in multiparametric MRI (mpMRI), is useful for tumor detection and localization in clinically significant prostate cancer (csPCa). The Prostate Imaging Reporting and Data System versions 2 and 2.1 (PI-RADS v2 and PI-RADS v2.1) emphasize the role of DWI in determining PIRADS Assessment Category in each of the transition and peripheral zones. In addition, several recent studies have demonstrated comparable performance of abbreviated biparametric MRI (bpMRI), which incorporates only T2-weighted imaging and DWI, compared with mpMRI with dynamic contrast-enhanced MRI. Therefore, further optimization of DWI is essential to achieve clinical application of bpMRI for efficient detection of csPC in patients with elevated PSA levels. Although DWI acquisition is routinely performed using single-shot echo-planar imaging, this method suffers from such as susceptibility artifact and anatomic distortion, which remain to be solved. In this review article, we will outline existing problems in standard DWI using the single-shot echo-planar imaging sequence; discuss solutions that employ newly developed imaging techniques, state-of-the-art technologies, and sequences in DWI; and evaluate the current status of quantitative DWI for assessment of tumor aggressiveness in PC.

Diagnostic performance of ESUR scoring system for extraprostatic prostate cancer extension: A meta-analysis

PURPOSE

We aimed to evaluate the diagnostic performance of the European Society of Urogenital Radiology (ESUR) scoring system for detection of extraprostatic extension (EPE) in prostate cancer (PCa) by performing a meta-analysis.

MATERIALS AND METHODS

A literature search of MEDLINE, EMBASE, Cochrane Library, Web of Science, and Google Scholar was performed to identify relevant studies from January 2012 to December 2020. We included diagnostic accuracy studies using ESUR scoring system for detection of EPE, and with prostatectomy histopathological results as the reference standard. Quality assessment was performed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The summary estimates of sensitivity and specificity were pooled using bivariate random-effects modeling. We conducted multiple subgroup analyses and meta-regression to explore varied clinical settings.

RESULTS

10 studies with a total of 1698 participants were included in this meta-analysis. Pooled sensitivity and specificity were 0.71 (95% CI 0.61-0.80) and 0.76 (95% CI 0.67-0.84), respectively, with the area under ROC of 0.80 (95% CI 0.77-0.84). The Higgins I² statistics demonstrated substantial heterogeneity in both sensitivity (I² = 86.5%) and specificity (I² = 91.6%), meta-regression revealed that the cutoff values (ESUR score ≥ 3 vs. ESUR score ≥ 4, P = 0.02) and malignancy rate (<40% vs. ≥40%, P = 0.04) were significant factors responsible for heterogeneity. Using endorectal coil and higher field strength (3.0 T) showed no additional benefit for EPE detection.

CONCLUSION

The evidence available for ESUR scoring system tends to show moderate diagnostic performance for detection of EPE, and the cutoff values (P = 0.02) and malignancy rate (P = 0.04) were significant factors contributed to the heterogeneity.

MRI-based radiomics models to assess prostate cancer, extracapsular extension and positive surgical margins

Purpose

To investigate the performance of magnetic resonance imaging (MRI)-based radiomics models for benign and malignant prostate lesion discrimination and extracapsular extension (ECE) and positive surgical margins (PSM) prediction.

Methods and materials

In total, 459 patients who underwent multiparametric MRI (mpMRI) before prostate biopsy were included. Radiomic features were extracted from both T2-weighted imaging (T2WI) and the apparent diffusion coefficient (ADC). Patients were divided into different training sets and testing sets for different targets according to a ratio of 7:3. Radiomics signatures were built using radiomic features on the training set, and integrated models were built by adding clinical characteristics. The areas under the receiver operating characteristic curves (AUCs) were calculated to assess the classification performance on the testing sets.

Results

The radiomics signatures for benign and malignant lesion discrimination achieved AUCs of 0.775 (T2WI), 0.863 (ADC) and 0.855 (ADC + T2WI). The corresponding integrated models improved the AUC to 0.851/0.912/0.905, respectively. The radiomics signatures for ECE achieved the highest AUC of 0.625 (ADC), and the corresponding integrated model achieved the highest AUC (0.728). The radiomics signatures for PSM prediction achieved AUCs of 0.614 (T2WI) and 0.733 (ADC). The corresponding integrated models reached AUCs of 0.680 and 0.766, respectively.

Conclusions

The MRI-based radiomics models, which took advantage of radiomic features on ADC and T2WI scans, showed good performance in discriminating benign and malignant prostate lesions and predicting ECE and PSM. Combining radiomics signatures and clinical factors enhanced the performance of the models, which may contribute to clinical diagnosis and treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00414-6.

Combining the Tumor Contact Length and Apparent Diffusion Coefficient Better Predicts Extraprostatic Extension of Prostate Cancer with Capsular Abutment: A 3 Tesla MR Imaging Study

Purpose: To assess the diagnostic performance of the tumor contact length (TCL) and apparent diffusion coefficient (ADC) for predicting extraprostatic extension (EPE) of prostate cancer with capsular abutment (CA).

Methods: Ninety-three patients with biopsy-proven prostate cancer underwent 3-Tesla MRI, including diffusion-weighted imaging (b value = 0, 2000 s/mm²) and radical prostatectomy. Two experienced radiologists, blinded to the clinicopathological data, retrospectively assessed the presence of CA on T2-weighted imaging (T2WI). TCL on T2WI and ADC values were measured on detecting CA in prostate cancer. We used the receiver operating characteristic curves to assess the diagnostic performance of TCL and ADC values for predicting EPE.

Results: CA was present in 58 prostate cancers among 93 patients. The cut-off value for TCL was 6.9 mm, which yielded an area under the curve (AUC) of 0.75. This corresponded to a sensitivity, specificity, and accuracy of 84.2%, 61.5%, and 69.0%, respectively. The cut-off value for ADC was 0.63 × 10^–3 mm²/s, which yielded an AUC of 0.76. This, in turn, corresponded to a sensitivity, specificity, and accuracy of 84.2%, 59.0%, and 67.2%, respectively. The combined cut-off value of TCL and ADC yielded an AUC of 0.82. The specificity (84.6%) and accuracy (81.0%) of the combined value were superior to their individual values (P < 0.05).

Conclusion: A combination of TCL and ADC values provided high specificity and accuracy for detecting EPE of prostatic cancer with CA.

Extraprostatic extension in prostate cancer: primer for radiologists

The presence of extraprostatic extension (EPE) on multiparametric MRI (mpMRI) is an important factor in determining the management of prostate cancer. EPE is an established risk factor for biochemical recurrence of prostate cancer after radical prostatectomy (RP) and patients with EPE may be considered for wider resection margins, non-nerve-sparing surgery, adjuvant radiation therapy (RT), or androgen deprivation therapy (ADT). Several statistical nomograms and scoring systems have been developed to predict pathological stage at time of RP but with varying accuracies. Using the current PI-RADS v2 mpMRI staging guidelines results in high specificity but lacks in sensitivity. These findings reveal the need for more standardization and further refinement of existing MRI protocols and prostate cancer prediction tools. Current studies have looked into indirect additional imaging criteria such as index tumor volume, length of capsular contact, and apparent diffusion coefficient. Measuring for these features can improve the robustness of mpMRI in staging prostate cancer, as they have been shown to be independent predictors of EPE. MRI/ultrasound fusion-guided targeted biopsy can detect EPE not found on standard biopsy. Collectively, these measurements and imaging techniques can augment the detection of EPE and subsequent risk stratification.

Value of adding the apparent diffusion coefficient to capsular contact for the prediction of extracapsular extension in prostate cancer

Objective

To determine whether evaluating the mean apparent diffusion coefficient (ADC) together with capsular contact (CC) adds value in the prediction of microscopic extracapsular extension (ECE) of prostate cancer.

Materials and Methods

Between January 2012 and December 2016, 383 patients underwent multiparametric magnetic resonance imaging (mpMRI) of the prostate. A total of 67 patients were selected for inclusion. Two radiologists (observers 1 and 2), working independently, performed qualitative and quantitative analyses of ECE, macroscopic ECE, and microscopic ECE. A third radiologist assessed the correlation with the clinical data, and two experienced pathologists reviewed all histopathological findings.

Results

Among the 67 patients, mpMRI showed lesions that were confined to the capsule in 44 (66.7%), had microscopic ECE in 12 (17.9%), and had macroscopic ECE in 11 (16.4%). There were no significant differences, in terms of the diagnostic accuracy, as measured by determining the area under the curve (AUC), of CC on T2-weighted images (CCT2), CC on diffusion-weighted imaging (CCDWI), and the mean ADC for the prediction of microscopic ECE, between observer 1 (AUC of 0.728, 0.691, and 0.675, respectively) and observer 2 (AUC of 0.782, 0.821, and 0.799, respectively). Combining the mean ADC with the CCT2 or CCDWI did not improve the diagnostic accuracy for either observer. There was substantial interobserver agreement for the qualitative evaluation of ECE, as demonstrated by the kappa statistic, which was 0.77 (0.66-0.87). The diagnostic accuracy (AUC) of the qualitative assessment for predicting microscopic ECE was 0.745 for observer 1 and 0.804 for observer 2, and the difference was less than significant. In a multivariate analysis, none of clinical or imaging parameters were found to be associated with ECE.

Conclusion

For the detection of microscopic ECE on mpMRI, CC appears to have good diagnostic accuracy, especially if the observer has considerable experience. Adding the mean ADC to the CCT2 or CCDWI does not seem to provide any significant improvement in that diagnostic accuracy.

Prostate MRI: practical guidelines for interpreting and reporting according to PI-RADS version 2.1

The increasing precision of multiparametric magnetic resonance imaging of the prostate, together with greater experience and standardization in its interpretation, has given this technique an important role in the management of prostate cancer, the most prevalent non-cutaneous cancer in men. This article reviews the concepts in PI-RADS version 2.1 for estimating the probability and zonal location of significant tumors of the prostate, using a practical approach that includes current considerations about the prerequisites for carrying out the test and recommendations for interpreting the findings. It emphasizes benign findings that can lead to confusion and the criteria for evaluating the probability of local spread, which must be included in the structured report.

Extraprostatic Tumor Extension: Comparison of Preoperative Multiparametric MRI Criteria and Histopathologic Correlation after Radical Prostatectomy

Background There are no standardized and well-validated criteria for assessing the risk of extraprostatic extension (EPE) of prostate cancer at preoperative multiparametric MRI. Purpose To compare diagnostic performance, intra- and interreader agreement, and correlations of MRI-based criteria for assessment of EPE after radical prostatectomy, including EPE grade, European Society of Urogenital Radiology (ESUR) score, Likert scale, and capsular contact length (CCL). Materials and Methods This retrospective study included consecutive men who underwent MRI and radical prostatectomy between July 2016 and March 2017. Two genitourinary radiologists independently estimated the probability of EPE by using four MRI-based scoring methods. The diagnostic accuracies and intra- and interobserver agreement were evaluated with area under the receiver operating characteristic curve (AUC) and κ statistics, respectively. Correlations between MRI-based score and histologic extent of EPE were analyzed by using the Spearman correlation coefficient (ρ). Results A total of 301 men (mean age ± standard deviation, 65 years ± 7) were evaluated. A total of 129 (42.9%) men had EPE. The AUC ranges of EPE grade, ESUR score, Likert scale, and CCL for assessment of EPE were 0.77-0.81, 0.79-0.81, 0.78-0.79, and 0.78-0.85, respectively, for the two readers. The Likert scale showed lower sensitivity (68.2% [88 of 129] for reader 1, 72.1% [93 of 129] for reader 2) than did EPE grade (77.5% [100 of 129] for reader 1, 79.8% [103 of 129] for reader 2; P ≤ .04). Intra- and interreader agreement were substantial (κ range, 0.61-0.74) for the four methods, with ESUR score showing the lowest values (κ = 0.61 and κ = 0.63, respectively). EPE grade showed highest correlation with histologic extent of EPE (ρ = 0.53 and ρ = 0.55 for circumferential length; ρ = 0.42 and ρ = 0.55 for radial length for readers 1 and 2, respectively; P < .001). Conclusion Extraprostatic extension (EPE) grade, European Society of Urogenital Radiology score, Likert scale, and capsular contact length showed good overall diagnostic performance; however, the EPE grade resulted in more reliable performance and had the highest correlation with histologic EPE extent. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Padhani and Petralia in this issue.

Prognostic Value of Pretreatment MRI in Patients With Prostate Cancer Treated With Radiation Therapy: A Systematic Review and Meta-Analysis

OBJECTIVE. Despite a substantial increase in the use of MRI for pretreatment evaluation of prostate cancer, its prognostic value in patients undergoing radiation therapy (RT) is not well known. Therefore, the purpose of this study was to systematically review the literature and perform a meta-analysis on the prognostic value of pretreatment MRI in patients with prostate cancer who underwent external beam radiation therapy (EBRT) or brachytherapy. MATERIALS AND METHODS. PubMed and Embase databases were searched for studies published on or before March 13, 2019. We included studies that evaluated pretreatment MRI as a prognostic factor in prostate cancer regarding biochemical recurrence (BCR), metastatic failure, and overall or cancer-specific mortality. Effect sizes were measured in terms of the hazard ratio (HR) and were meta-analytically pooled using the random-effects model. The quality of the studies was independently evaluated using the Quality in Prognostic Studies tool. RESULTS. Twelve studies (2205 patients) were included. All studies assessed BCR; metastasis was evaluated in three studies, and mortality was evaluated in one study. Extraprostatic extension (EPE), seminal vesicle invasion (SVI), large tumor size or volume, number of sextants involved, and tumor involvement of prostatic apex were significant prognostic factors of BCR (pooled HRs = 1.50-4.47). EPE, larger tumor size, greater tumor volume, presence of metastatic pelvic lymph nodes (LNs), and presence of SVI were significant risk factors for metastasis (pooled HRs = 1.12-11.96). Pelvic LN metastasis was significantly predictive of cancer-specific mortality (HR = 4.45 [95% CI, 1.30-15.23]). CONCLUSION. Several pretreatment MRI findings were significant prognostic factors in patients with prostate cancer who underwent RT.

Predicting side-specific prostate cancer extracapsular extension: a simple decision rule of PSA, biopsy, and MRI parameters

Objective

To develop an easy-to-use side-specific tool for the prediction of prostate cancer extracapsular extension (ECE) using clinical, biopsy, and MRI parameters.

Materials and methods

Retrospective analysis of patients who underwent radical prostatectomy preceded by staging multiparametric MRI of the prostate was performed. Multivariate logistic regression analysis was used to choose independent predictors of ECE. Continuous variables were transformed to categorical ones by choosing threshold values using spline knots or testing thresholds used in previously described models. Internal validation of the rule was carried out as well as validation of other algorithms on our group was performed.

Results

In the analyzed period of time, 88 out of 164 patients who underwent radical prostatectomy met inclusion criteria. ECE was evidenced at radical prostatectomy in 41 patients (46.6%) and in 53 lobes (30.1%). In the multivariate analysis PSA, total percentage of cancerous tissue in cores (%PCa) and maximum tumour diameter (MTD) of Likert 3–5 lesions on MRI were independent predictors of ECE. The following rule for predicting side-specific ECE was proposed: %PCa ≥ 15% OR MTD ≥ 15 mm OR PSA ≥ 20 ng/mL. Internal validation of the algorithm revealed safe lower confidence limits for sensitivity and NPV, proving that model offers accurate risk grouping that can be safely used in decision-making.

Conclusion

The rule developed in this study makes ECE prediction fast, intuitive, and side-specific. However, until validated externally it should be used with caution.

Multiparametric MRI - local staging of prostate cancer and beyond

Background Accurate local staging is critical for treatment planning and prognosis in patients with prostate cancer (PCa). The primary aim is to differentiate between organ-confined and locally advanced disease with the latter carrying a worse clinical prognosis. Multiparametric MRI (mpMRI) is the imaging modality of choice for the local staging of PCa and has an incremental value in assessing pelvic nodal disease and bone involvement. It has shown superior performance compared to traditional staging based on clinical nomograms, and provides additional information on the site and extent of disease. MRI has a high specificity for diagnosing extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node (LN) metastases, however, sensitivity remains poor. As a result, extended pelvic LN dissection remains the gold standard for assessing pelvic nodal involvement, and there has been recent progress in developing advanced imaging techniques for more distal staging. Conclusions T2W-weighted imaging is the cornerstone for local staging of PCa. Imaging at 3T and incorporating both diffusion weighted and dynamic contrast enhanced imaging can further increase accuracy. "Next generation" imaging including whole body MRI and PET-MRI imaging using prostate specific membrane antigen (68Ga-PSMA), has shown promising for assessment of LN and bone involvement as compared to the traditional work-up using bone scintigraphy and body CT.

Apparent diffusion coefficient in extraprostatic extension of prostate cancer: a systematic review and diagnostic meta-analysis

Objective: To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) for local staging of prostate cancer. Methods: Databases of Web of Science, MEDLINE (Ovid and PubMed), Cochrane Library, EMBASE, and Google Scholar were searched up to May 31, 2018, with language restricted to English. All studies concerning multiparametric magnet resonance imaging (mpMRI) with ADC for detection of extracapsular extension (ECE, T3a) and/or extraprostatic extension (EPE, overall stage of T3) were identified by two reviewers independently, and quality of included studies was evaluated using Quality Assessment of Diagnostic Accuracy Studies-2 tool. True positive, false positive, false negative and true negative of each study were extracted to reconstruct the 2×2 tables for evaluating diagnostic accuracy. Summary estimates of sensitivity, specificity, and corresponding 95% CIs were calculated with bivariate model and hierarchical summary receiver operating characteristic model, then presented in forest plots. Multiple subgroup analyses and meta-regression were performed, and publication bias was evaluated with Deeks funnel. Results: A total of 18 studies were included, with 6 involved ECE and 12 for EPE. Pooled sensitivity was 80.5% (95% CI 76.5-83.9%) with specificity of 69.1% (95% CI 62.3-75.2%). Multiple subgroup analyses showed that if ADC and length of capsular contact are regarded as independent predictors, pooled sensitivity was 85% (95% CI 77-90%) and 81.1% (95% CI 76.0-85.3%), with specificity of 70.8% (95% CI 56.3-82.0%) and 66.6% (95% CI 57.6-74.5%), respectively. Meta-regression demonstrated that there was no substantially significant difference in types of coil, magnet field strength (1.5T versus 3.0T), and analysis method (per-lesion versus per-patient). Conclusion: By introducing ADC to MRI, we could obtain favorable sensitivity for diagnostic performance of EPE, but with a little decreased specificity.

Contribution of Radiology to Staging of Prostate Cancer

Accurate tumor detection and establishment of disease extent are important for optimal management of prostate cancer. Disease stage, beginning with identification of the index prostate lesion, followed by primary tumor, lymph node, and distant metastasis evaluation, provide crucial clinical information that not only have prognostic and predictive value, but guide patient management. A wide array of radiological imaging modalities including ultrasound, computed tomography, and magnetic resonance imaging have been used for the purpose of prostate cancer staging with variable diagnostic performance. Especially, the last years have seen remarkable technological advances in magnetic resonance imaging technology, enabling referring clinicians and radiologists to obtain even more valuable data regarding staging of prostate cancer. Marked improvements have been seen in detection of the index prostate lesion and evaluation of extraprostatic extension while further improvements are still needed in identifying metastatic lymph nodes. Novel approaches such as whole-body MRI are emerging for more accurate and reproducible assessment of bone metastasis. Post-treatment assessment of prostate cancer using radiological imaging is a topic with rapidly changing clinical context and special consideration is needed for the biochemical setting, that is, the relatively high serum prostate-specific antigen levels in studies assessing the value of radiological imaging for post-treatment assessment and emerging therapeutic approaches such as early salvage radiation therapy. The scope of this review is to provide the reader insight into the various ways radiology contribute to staging of prostate cancer in the context of both primary staging and post-treatment assessment. The strengths and limitations of each imaging modality are highlighted as well as topics that warrant future research.

Added Value of Multiparametric Magnetic Resonance Imaging to Clinical Nomograms for Predicting Adverse Pathology in Prostate Cancer

PURPOSE

We examined the additional value of preoperative prostate multiparametric magnetic resonance imaging and transrectal ultrasound/multiparametric magnetic resonance imaging fusion guided targeted biopsy when performed in combination with clinical nomograms to predict adverse pathology at radical prostatectomy.

MATERIALS AND METHODS

We identified all patients who underwent 3 Tesla multiparametric magnetic resonance imaging prior to fusion biopsy and radical prostatectomy. The Partin and the MSKCC (Memorial Sloan Kettering Cancer Center) preradical prostatectomy nomograms were applied to estimate the probability of organ confined disease, extraprostatic extension, seminal vesicle invasion and lymph node involvement using transrectal ultrasound guided systematic biopsy and transrectal ultrasound/multiparametric magnetic resonance imaging fusion guided targeted biopsy Gleason scores. With radical prostatectomy pathology as the gold standard we developed multivariable logistic regression models based on these nomograms before and after adding multiparametric magnetic resonance imaging to assess any additional predictive ability.

RESULTS

A total of 532 patients were included in study. When multiparametric magnetic resonance imaging findings were added to the systematic biopsy based MSKCC nomogram, the AUC increased by 0.10 for organ confined disease (p <0.001), 0.10 for extraprostatic extension (p = 0.003), 0.09 for seminal vesicle invasion (p = 0.011) and 0.06 for lymph node involvement (p = 0.120). Using Gleason scores derived from targeted biopsy compared to systematic biopsy provided an additional predictive value of organ confined disease (Δ AUC 0.07, p = 0.003) and extraprostatic extension (Δ AUC 0.07, p = 0.048) at radical prostatectomy with the MSKCC nomogram. Similar results were obtained using the Partin nomogram.

CONCLUSIONS

Magnetic resonance imaging alone or in addition to standard clinical nomograms provides significant additional predictive ability of adverse pathology at the time of radical prostatectomy. This information can be greatly beneficial to urologists for preoperative planning and for counseling patients regarding the risks of future therapy.

Accuracy in local staging of prostate cancer by adding a three-dimensional T2-weighted sequence with radial reconstructions in magnetic resonance imaging

Background

The evidence supporting the use of magnetic resonance imaging (MRI) in prostate cancer detection has been established, but its accuracy in local staging is questioned.

Purpose

To investigate the additional value of multi-planar radial reconstructions of a three-dimensional (3D) T2-weighted (T2W) MRI sequence, intercepting the prostate capsule perpendicularly, for improving local staging of prostate cancer.

Material and Methods

Preoperative, bi-parametric prostate MRI examinations in 94 patients operated between June 2014 and January 2015 where retrospectively reviewed by two experienced abdominal radiologists. Each patient was presented in two separate sets including diffusion-weighted imaging, without and with the 3D T2W set that included radial reconstructions. Each set was read at least two months apart. Extraprostatic tumor extension (EPE) was assessed according to a 5-point grading scale. Sensitivity and specificity for EPE was calculated and presented as receiver operating characteristics (ROC) with area under the curve (AUC), using histology from whole-mount prostate specimen as gold standard. Inter-rater agreement was calculated for the two different reading modes using Cohen's kappa.

Results

The AUC for detection of EPE for Readers 1 and 2 in the two-dimensional (2D) set was 0.70 and 0.68, respectively, and for the 2D + 3D set 0.62 and 0.65, respectively. Inter-rater agreement (Reader 1 vs. Reader 2) on EPE using Cohen's kappa for the 2D and 2D + 3D set, respectively, was 0.42 and 0.17 (i.e. moderate and poor agreement, respectively).

Conclusion

The addition of 3D T2W MRI with radial reconstructions did not improve local staging in prostate cancer.

A prospective study evaluating indirect MRI-signs for the prediction of extraprostatic disease in patients with prostate cancer: tumor volume, tumor contact length and tumor apparent diffusion coefficient

OBJECTIVE

The aim of this study was to evaluate three indirect MRI signs for predicting extraprostatic disease in patients referred to radical prostatectomy: index tumor volume (MTV), apparent diffusion coefficient (ADC) and tumor contact length (TCL).

MATERIALS AND METHODS

This prospective study included 183 patients with biopsy proven prostate cancer. In all patients the MTV (ml), ADC (× 10^-5 mm²/s) and TCL (mm) of the index tumor were registered at the preoperative MRI. Whole-mounted microscopical examination classified each patient as having either localized- or extraprostatic disease. The Youden index was used to identify the optimal cut-off values for predicting extraprostatic disease. Univariate regression analyses were conducted to estimate the odds ratio (OR) with 95% confidence intervals (CI). Results were stratified upon zonal location of the index tumor.

RESULTS

Extraprostatic disease was identified in 103 (56%) patients. The risk of extraprostatic disease was nine times higher in peripheral zone tumors with ADC ≤ 89 (OR 9.1, 95% CI 4.2-19.6), five times higher in MTV ≥ 0.9 ml (OR 5.5, 95% CI 2.6-11.4) and five times higher in case of TCL ≥ 14 mm (OR 4.9, 95% CI 2.3-10.2). None of the indirect MRI signs could predict extraprostatic disease for transition zone tumors.

CONCLUSION

The MTV, ADC and TCL are all significant predictors of extraprostatic disease for peripheral zone tumors, while none of the indirect signs were useful for transition zone tumors.

A novel tool for predicting extracapsular extension during graded partial nerve sparing in radical prostatectomy

OBJECTIVES

To create a statistical tool for the estimation of extracapsular extension (ECE) level of prostate cancer and determine the nerve-sparing (NS) approach that can be safely performed during radical prostatectomy (RP).

PATIENTS AND METHODS

A total of 11 794 lobes, from 6 360 patients who underwent robot-assisted RP between 2008 and 2016 were evaluated. Clinicopathological features were included in a statistical algorithm for the prediction of the maximum ECE width. Five multivariable logistic models were estimated for: presence of ECE and ECE width of >1, >2, >3, and >4 mm. A five-zone decision rule based on a lower and upper threshold is proposed. Using a graphical interface, surgeons can view patient's pre-treatment characteristics and a curve showing the estimated probabilities for ECE amount together with the areas identified by the decision rule.

RESULTS

Of the 6 360 patients, 1 803 (28.4%) were affected by non-organ-confined disease. ECE was present in 1 351 lobes (11.4%) and extended beyond the capsule for >1, >2, >3, and >4 mm in 498 (4.2%), 261 (2.2%), 148 (1.3%), 99 (0.8%) cases, respectively. ECE width was up to 15 mm (interquartile range 1.00-2.00). The five logistic models showed good predictive performance, the area under the receiver operating characteristic curve was: 0.81 for ECE, and 0.84, 0.85, 0.88, and 0.90 for ECE width of >1, >2, >3, and >4 mm, respectively.

CONCLUSION

This novel tool predicts with good accuracy the presence and amount of ECE. Furthermore, the graphical interface available at www.prece.it can support surgeons in patient counselling and preoperative planning.

Impact of the Prostate Imaging Reporting and Data System, Version 2, on MRI Diagnosis for Extracapsular Extension of Prostate Cancer

OBJECTIVE

The purpose of this study is to validate the Prostate Imaging Reporting and Data System, version 2 (PI-RADSv2), in assessing extracapsular extension (ECE), compared with PI-RADS, version 1 (PI-RADSv1).

MATERIALS AND METHODS

A total of 210 patients with clinically localized prostate cancer underwent MRI and radical prostatectomy. Two readers independently interpreted the MR images. In PI-RADSv1, 5-point ECE risk scoring was used. In PI-RADSv2, ECE criteria included morphologic features and a tumor-capsule contact length (CL) greater than 10 mm. The diagnostic performance of each PI-RADS version and the cutoff CL were evaluated.

RESULTS

ECE was found in 56 patients (26.7%). In PI-RADSv1, maximal accuracy was achieved with a risk score of 3 or greater. At this threshold, positive findings on PI-RADSv1 and PI-RADSv2 were identified in 21.0-34.3% and 49.0-51.4% of patients, respectively. Compared with PI-RADSv1, PI-RADSv2 had higher negative predictive values (84.9-89.1% vs 96.3-97.1%, respectively; p = 0.003 and 0.021, for each reader). PI-RADSv1 and PI-RADSv2 had positive predictive values of 56.9-70.5% and 49.1-50.5%, respectively (p = 0.025 and 0.300, respectively). Interobserver kappa values for PI-RADSv1 and PI-RADSv2 were 0.511 and 0.781, respectively. The best cutoff CL was greater than 10 mm among patients without morphologic features of ECE. For patients positive for ECE on the basis of PI-RADSv2 but not PI-RADSv1, 73.3-74.1% of prostate cancer cases with a biopsy Gleason score of 7 or less and 35.7-44.4% of cases with a biopsy Gleason score of 8 or higher were overstaged.

CONCLUSION

PI-RADSv2 reduces understaging and improves interobserver agreement in ECE assessment. However, overstaging is a concern, and the biopsy Gleason score may have a complementary role in reducing overstaging.

Prostate MRI prior to radical prostatectomy: effects on nerve sparing and pathological margin status

OBJECTIVES

The aim of this study was to assess the positive surgical margin (PSM) and nerve sparing (NS) rates in patients who underwent prostate MRI (pMRI) prior to radical prostatectomy (RP) and compare them with matched, nonimaged control RP patients.

METHODS

We identified 204 men who underwent preoperative pelvic MRI (pelMRI), of whom 176 (86.3%) underwent pMRIs, within 60 days of RP, and compared them (1:1) with a nonim-aged control group matched by surgeon, age, race, body mass index (BMI), prostate-specific antigen (PSA), pathological Gleason score, prostate specimen weight, and RP year.

RESULTS

The rates of nonfocal extracapsular extension (nfECE) on RP pathology in the MRI and control groups were similar. PSM rates were lower in the MRI group (13.7% vs 19.3%; P=0.14), but the difference did not meet statistical significance; this was also the case in patients with nfECE on RP pathology (27.7% vs 39.5%; P=0.3). NS rates were similar between groups. In the MRI group, 54 (26.5%) patients had an MRI suspicious for nfECE; their PSM rate (20.4%) was higher than that of patients with an MRI not suspicious for nfECE (11.3%; P=0.11), but the difference lacked statistical significance; the former group had significantly lower rates of NS. Limitations of the study include sample power and nonuniform heeding of MRI results by each surgeon.

CONCLUSION

MRI did not significantly decrease the rates of PSM, including in the subset of patients with nfECE on final pathology. Even wider resection may be necessary in patients with MRIs suggesting locally-advanced disease. Studies with greater power are needed.

Length of capsular contact on prostate MRI as a predictor of extracapsular extension: which is the most optimal sequence?

Background Length of capsular contact (LCC) is a promising biomarker for predicting extracapsular extension (ECE), but the most optimal magnetic resonance imaging (MRI) sequence for measuring LCC is yet to be determined. Purpose To evaluate LCC using different MRI sequences for determining ECE in prostate cancer. Material and Methods A total of 185 patients underwent prostate MRI followed by radical prostatectomy. LCC was measured separately on T2-weighted (T2W) images, apparent diffusion coefficient (ADC) maps, and dynamic contrast-enhanced (DCE) MRI. LCCs (LCC_T2, LCC_ADC, LCC_DCE, and LCC_max [greatest value of 3 LCCs]) were compared between sequences using Wilcoxon signed rank test and was tested for determining ECE using the Mann-Whitney U test, ROC curve analysis, and logistic regression analysis. Results There were no significant differences among LCCs ( P = 0.333-0.837). All LCCs were significantly greater in patients with ECE ( P < 0.001). The optimal threshold value for predicting ECE was >14, >13, >12, and >14 mm for LCC_T2, LCC_ADC, LCC_DCE, and LCC_max, respectively. LCC_max yielded the highest area under the curve (0.895) which was significantly greater than that by LCC_ADC (0.858, P = 0.030). Otherwise, there were no significant difference between LCCs ( P = 0.052-0.985). At univariate analysis, age, clinical stage, PSA, Gleason score, and all LCCs were significantly associated with ECE ( P < 0.001-0.040). At multivariate analysis, GS ( P ≤ 0.008) and all LCCs ( P < 0.001) were independently predictive factors. Conclusion LCC measured on any sequence was significantly different in patients with and without ECE and was independently associated with the presence of ECE. Although LCC_max showed the greatest ability to predict ECE, there was relatively equivalent performance among different MRI sequences.

Predicting biochemical recurrence in patients with high-risk prostate cancer using the apparent diffusion coefficient of magnetic resonance imaging

Purpose

We aimed to investigate whether the apparent diffusion coefficient (ADC) value in diffusion-weighted magnetic resonance imaging predicts the prognoses of patients with high-risk prostate cancer.

Materials and Methods

A total of 157 patients with high-risk prostate cancer (based on D'Amico's criteria) were included in the analysis. Patients underwent preoperative 3.0 Tesla magnetic resonance imaging within 2 months before radical prostatectomy. Those who received neoadjuvant hormone therapy (33 persons) or radiation therapy (18 persons) were excluded. The ADC of the tumor calculated from 2 b-values (0 and 1,000 s/mm²) was measured. Areas under receiver operating characteristics curves were calculated to maximize the accuracy of the ADC value. Based on the obtained cutoff value, the patients were stratified into 2 groups: Group A consisted of patients with ADC values <746×10⁻⁶ mm²/s and group B comprised those with ADC values ≥746×10⁻⁶ mm²/s.

Results

Group A showed higher rate of lymph positive and biochemical recurrence (BCR) rates than group B. Kaplan-Meier analysis showed that the BCR-free survival rate of group A was much lower than that of group B (p<0.001). On Cox proportional regression analyses, ADC group A (hazard ratio [HR], 3.238, p=0.002) and pathologic lymph node positive (HR, 2.242; p=0.009) were independent predictors of BCR.

Conclusions

In patients with high-risk prostate cancer, ADC value is significantly associated with BCR-free survival. Therefore, the ADC value is a useful tool for predicting the prognoses of these high-risk patients.

Incremental value of high b value diffusion-weighted magnetic resonance imaging at 3-T for prediction of extracapsular extension in patients with prostate cancer: preliminary experience

PURPOSE

To investigate whether high b value diffusion-weighted imaging (DWI) contributes to the improvement of diagnostic ability of extracapsular extension (ECE) in prostate cancer (PC).

MATERIALS AND METHODS

Forty-three patients with PC underwent multiparametric MRI including DWI (b values: 0, 2000 s/mm²) at 3-T. Two radiologists assessed the presence of ECE and the diagnostic certainty degree using conventional diagnostic method by consensus. Tumor apparent diffusion coefficient (ADC, ×10^-3 mm²/s) was also measured. Independent predictors of ECE were identified among PSA, tumor ADC, Gleason score, and conventional MRI. ECE in patients with low diagnostic certainty by conventional MRI was further reevaluated using ADC cutoff value, and the results were combined with those of patients with high diagnostic certainty by conventional MRI (MRI + ADC method).

RESULTS

Tumor ADC was an independent predictor of ECE, and the ADC cutoff value was 0.72. The sensitivity, specificity, and accuracy of conventional MRI and MRI + ADC method in the diagnosis of ECE were 44, 92, and 72%, and 78, 96, and 88%, respectively. Among MRI findings leading to the judgement of low diagnostic certainty, broad tumor contact was most common (72% of the patients).

CONCLUSIONS

The addition of ADC obtained with high b value DWI at 3-T to conventional MRI improved the diagnostic ability of ECE.

Multi-parametric MRI of the prostate: Factors predicting extracapsular extension at the time of radical prostatectomy

Objective

Extracapsular extension (ECE) of prostate cancer is a poor prognostic factor associated with progression, recurrence after treatment, and increased prostate cancer-related mortality. Accurate staging prior to radical prostatectomy is crucial in avoidance of positive margins and when planning nerve-sparing procedures. Multi-parametric magnetic resonance imaging (mpMRI) of the prostate has shown promise in this regard, but is hampered by poor sensitivity. We sought to identify additional clinical variables associated with pathologic ECE and determine our institutional accuracy in the detection of ECE amongst patients who went on to radical prostatectomy.

Methods

mpMRI studies performed between the years 2012 and 2014 were cross-referenced with radical prostatectomy specimens. Predictive properties of ECE as well as additional clinical and biochemical variables to identify pathology-proven prostate cancer ECE were analyzed.

Results

The prevalence of ECE was 32.4%, and the overall accuracy of mpMRI for ECE was 84.1%. Overall mpMRI sensitivity, specificity, positive predictive value, and negative predictive value for detection of ECE were 58.3%, 97.8%, 93.3%, and 81.5%, respectively. Specific mpMRI characteristics predictive of pathologic ECE included primary lesion size ((20.73 ± 9.09) mm, mean ± SD, p < 0.001), T2 PIRADS score (p = 0.009), overall primary lesion score (p < 0.001), overall study suspicion score (p = 0.003), and MRI evidence of seminal vesicle invasion (SVI) (p = 0.001).

Conclusion

While mpMRI is an accurate preoperative assessment tool for the detection of ECE, its overall sensitivity is poor, likely related to the low detection rate of standard protocol MRI for microscopic extraprostatic disease. The additional mpMRI findings described may also be considered in surgical margin planning prior to radical prostatectomy.

Evaluation of extracapsular extension in prostate cancer using qualitative and quantitative multiparametric MRI

PURPOSE

To investigate the value of multiparametric magnetic resonance imaging (mpMRI) for extracapsular extension (ECE) in prostate cancer (PCa).

MATERIALS AND METHODS

In all, 292 patients who received radical prostatectomy and underwent preoperative mpMRI at 3T were enrolled retrospectively. For determining the associations with ECE, the likelihood of ECE was assessed qualitatively on T₂ -weighted imaging (T₂ WI) and combined T₂ WI and diffusion-weighted imaging (DWI) or dynamic contrast-enhanced imaging (DCEI). Quantitative MRI parameters were measured in PCa based on histopathological findings. Two models for detecting ECE including imaging and clinical parameters were developed using multivariate analysis: Model 1 excluding combined T₂ WI and DWI and DCEI and Model 2 excluding combined T₂ WI and DWI, and combined T₂ WI and DCEI. Diagnostic performance of imaging parameters and models was evaluated using the area under the receiver operating characteristics curve (Az).

RESULTS

For detecting ECE, the specificity, accuracy, and Az of combined T₂ WI and DWI or DCEI were statistically better than those of T₂ WI (P < 0.05), and all quantitative MRI parameters showed a statistical difference between the patients with and without ECE (P < 0.05). On multivariate analysis, significant independent markers in Model 1 were combined T₂ WI and DWI, combined T₂ WI and DCEI, and K^trans (P < 0.05). In Model 2, significant markers were combined T₂ WI and DWI and DCEI, K^trans , K_ep , and Ve (P < 0.05). The Az values of models 1 and 2 were 0.944 and 0.957, respectively.

CONCLUSION

mpMRI may be useful to improve diagnostic accuracy of the models for determining the associations with ECE in PCa.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;45:1760-1770.

Prostate cancer-specific mortality after radical prostatectomy: value of preoperative MRI

BACKGROUND

Although magnetic resonance imaging (MRI) is currently indispensable in the preoperative setting of biopsy-proven prostate cancer, the value of preoperative MRI for predicting prostate cancer-specific mortality (PCSM) is not well known.

PURPOSE

To evaluate the value of MRI for predicting PCSM in patients who underwent radical prostatectomy (RP) for localized prostate cancer.

MATERIAL AND METHODS

A total of 318 patients underwent MRI followed by RP. MRI was assessed for the presence of clinically significant cancer using a five-point Likert scale, where ≥4 was considered positive. Cox proportional hazards regression analyses was used to determine the relationship of preoperative factors with PCSM. PCSM was calculated using the Kaplan-Meier method and compared between factors using the log-rank test.

RESULTS

After a median follow-up of 104 months, 11 (3.5%) patients died of prostate cancer. One hundred and four (32.7%) patients had clinically significant prostate cancer on MRI. Univariate analysis revealed that Gleason grade, greatest percentage of involved core length (GPCL), and clinically significant cancer on MRI were significantly related to PCSM (P = 0.001-0.003). Multivariate analysis showed that GPCL (hazard ratio [HR], 1.028; 95% confidence interval [CI], 1.000-1.057; P = 0.048) and clinically significant cancer on MRI (HR, 10.903; 95% CI, 1.287-92.374; P = 0.028) were independent predictors of PCSM. The 5 - and 10-year PCSM rates were 0.6% and 1.3% in patients with GPCL <50% and 5.1% and 8.6% in those with GPCL ≥50% (P = 0.012). Patients without clinically significant cancer on MRI showed 5 - and 10-year PCSM rates of 0% and 0.5%, respectively, whereas those with clinically significant cancer on MRI showed rates of 8% and 14.2%, respectively (P < 0.001).

CONCLUSION

Preoperative MRI and GPCL may be used to predict PCSM after RP.

Multiparametric magnetic resonance imaging: Current role in prostate cancer management

Digital rectal examination, serum prostate-specific antigen screening and transrectal ultrasound-guided biopsy are conventionally used as screening, diagnostic and surveillance tools for prostate cancer. However, they have limited sensitivity and specificity. In recent years, the role of multiparametric magnetic resonance imaging has steadily grown, and is now part of the standard clinical management in many institutions. In multiparametric magnetic resonance imaging, the morphological assessment of T2-weighted imaging is correlated with diffusion-weighted imaging, dynamic contrast-enhanced imaging perfusion and/or magnetic resonance spectroscopic imaging. Multiparametric magnetic resonance imaging is currently regarded as the most sensitive and specific imaging technique for the evaluation of prostate cancer, including detection, staging, localization and aggressiveness evaluation. This article presents an overview of multiparametric magnetic resonance imaging, and discusses the current role of multiparametric magnetic resonance imaging in the different fields of prostate cancer management.

Staging of prostatic carcinoma at 1.5-T MRI: correlation of a simplified MRI exam with whole-mount radical prostatectomy specimens

OBJECTIVE

To retrospectively analyze the accuracy of simplified multiparametric MRI at 1.5 T for local staging by using whole-mount-section histopathological analysis as the standard of reference.

METHODS

123 consecutive patients underwent T2 weighted, T1 weighted and diffusion-weighted MRI without endorectal coil prior to radical prostatectomy. The accuracy of predicting extracapsular extension (ECE) (T3a) was assessed using direct signs or the combination of direct and indirect signs of extraprostatic extension. The accuracy of predicting seminal vesicle invasion (T3b) was evaluated, taking into account different routes of seminal vesicle involvement. Finally, adjacent organ invasion (T4) was evaluated in this patient population.

RESULTS

Histopathology showed T3a, T3b and T4 in 61, 28 and 9 cases, respectively. The use of direct signs of extraprostatic extension showed a sensitivity of 57.4% and specificity of 91.9%. The combination of direct signs and indirect signs improved sensitivity (85.2%) at the expense of moderate loss of specificity (83.9%). MR sensitivity for the detection of seminal vesicle invasion was low (53.6%); however, it was dependent on the route of seminal vesicle tumour infiltration. MR sensitivity and specificity for adjacent organ invasion were 88.9% and 99.1%.

CONCLUSION

Simplified MRI study at 1.5 T provides a relatively high sensitivity for detecting ECE (T3a) when using the combination of indirect and direct signs. However, this high sensitivity reading is at the cost of a moderate loss of specificity. Invasion of the seminal vesicles (T3b) occurs most often along the ejaculatory duct complex with low MR sensitivity.

ADVANCES IN KNOWLEDGE

Simplified MRI study at 1.5 T without endorectal coil could be used for the local T staging of prostate cancer.