Scoring systems used for the interpretation and reporting of multiparametric MRI for prostate cancer detection, localization, and characterization: could standardization lead to improved utilization of imaging within the diagnostic pathway?

Surgeon seniority and experience have no effect on CaP detection rates using MRI/TRUS fusion-guided targeted biopsies

OBJECTIVE

To determine (i) whether urologist seniority and experience are associated with prostate cancer (CaP) and clinically significant CaP (csCaP) detection rates using magnetic resonance imaging/ultrasound (MRI/US) fusion-guided targeted biopsies, taking multiparametric magnetic resonance imaging (mpMRI) as the reference standard, and (ii) if cancer detection rates (CDR) differ across regions of the prostate using Dickinson's 27-sector map, regardless of seniority.

METHODS

We retrospectively reviewed a consecutive series of patients with suspicion of prostate cancer who underwent targeted and systematic biopsies at 1 center by 1 of 7 urologists (2 seniors and 5 juniors) between January 1, 2016 and December 31, 2021, following positive mpMRI.

RESULTS

The cohort comprised 403 patients (454 lesions) aged 67.7±6.8. The combined (junior and senior) CDR was 57% for CaP and 28% for csCaP. There were no differences in CDR between junior and senior urologists for CaP (58% vs. 55%, P = 0.538) or csCaP (29% vs. 26%, P = 0.58). A general trend was observed for the learning curve, which indicated increasing CDR with urologist experience. Across the 27 sectors, combined CDR ranged between 39% and 99% for CaP and 1% to 67% for csCaP. When grouping anterior vs. posterior sectors, there were no differences in combined CDR of CaP (64% vs. 67%, P = 0.48) and csCaP (31% vs. 38%, P = 0.19) CONCLUSIONS: Urologist seniority is not associated with CDR, urologist experience tends to improve cancer detection, and CDR does not differ between the anterior and posterior regions of the prostate.

Advanced strain elastography is a reliable approach for prostate cancer detection in patients with elevated PSA levels

This study aimed to examine the validity and reproducibility of strain elastography (SE) for detecting prostate cancer (PCa) in patients with elevated prostate-specific antigen (PSA) levels. The study included 107 patients with elevated PSA levels. All eligible patients underwent transrectal ultrasound (TRUS) with real-time elastography (RTE) to detect suspicious lesions. Two readers independently evaluated the lesions and assigned a strain ratio and elastography score to each lesion. Histopathology was used as a reference standard to estimate the validity of RTE in predicting malignant lesions. An intraclass correlation (ICC) was performed to detect reliability of the strain ratios and elastography scores. TRUS-guided biopsy detected malignancies in 64 (59.8%) patients. TRUS with RTE revealed 122 lesions. The strain ratio index (SRI) cut-off values to diagnose malignancy were 4.05 and 4.35, with sensitivity, specificity, and accuracy of 94.7%, 91.3%, and 93.4%, respectively. An elastography score > 3 was the best cut-off value for detecting malignancy. According to readers, the sensitivity, specificity, and accuracy were 91.3-94.7%, 89.5-93.4%, and 91.3-90.9%, respectively. Excellent inter-reader agreement was recorded for SRI and elastography scores, with ICC of 0.937 and 0.800, respectively. SE proves to be an efficient tool for detecting PCa with high accuracy in patients with elevated PSA levels.

Prostate cancer epidemiology and prognostic factors in the United States

Objective

Using the latest cohort study of prostate cancer patients, explore the epidemiological trend and prognostic factors, and develop a new nomogram to predict the specific survival rate of prostate cancer patients.

Methods

Patients with prostate cancer diagnosed from January 1, 1975 to December 31, 2019 in the Surveillance, Epidemiology, and End Results Program (SEER) database were extracted by SEER stat software for epidemiological trend analysis. General clinical information and follow-up data were also collected from 105 135 patients with pathologically diagnosed prostate cancer from January 1, 2010 to December 1, 2019. The factors affecting patient-specific survival were analyzed by Cox regression, and the factors with the greatest influence on specific survival were selected by stepwise regression method, and nomogram was constructed. The model was evaluated by calibration plots, ROC curves, Decision Curve Analysis and C-index.

Results

There was no significant change in the age-adjusted incidence of prostate cancer from 1975 to 2019, with an average annual percentage change (AAPC) of 0.45 (95% CI:-0.87~1.80). Among the tumor grade, the most significant increase in the incidence of G2 prostate cancer was observed, with an AAPC of 2.99 (95% CI:1.47~4.54); the most significant decrease in the incidence of G4 prostate cancer was observed, with an AAPC of -10.39 (95% CI:-13.86~-6.77). Among the different tumor stages, the most significant reduction in the incidence of localized prostate cancer was observed with an AAPC of -1.83 (95% CI:-2.76~-0.90). Among different races, the incidence of prostate cancer was significantly reduced in American Indian or Alaska Native and Asian or Pacific Islander, with an AAPC of -3.40 (95% CI:-3.97~-2.82) and -2.74 (95% CI:-4.14~-1.32), respectively. Among the different age groups, the incidence rate was significantly increased in 15-54 and 55-64 age groups with AAPC of 4.03 (95% CI:2.73~5.34) and 2.50 (95% CI:0.96~4.05), respectively, and significantly decreased in ≥85 age group with AAPC of -2.50 (95% CI:-3.43~-1.57). In addition, age, tumor stage, race, PSA and gleason score were found to be independent risk factors affecting prostate cancer patient-specific survival. Age, tumor stage, PSA and gleason score were most strongly associated with prostate cancer patient-specific survival by stepwise regression screening, and nomogram prediction model was constructed using these factors. The Concordance indexes are 0.845 (95% CI:0.818~0.872) and 0.835 (95% CI:0.798~0.872) for the training and validation sets, respectively, and the area under the ROC curves (AUC) at 3, 6, and 9 years was 0.7 or more for both the training and validation set samples. The calibration plots indicated a good agreement between the predicted and actual values of the model.

Conclusions

Although there was no significant change in the overall incidence of prostate cancer in this study, significant changes occurred in the incidence of prostate cancer with different characteristics. In addition, the nomogram prediction model of prostate cancer-specific survival rate constructed based on four factors has a high reference value, which helps physicians to correctly assess the patient-specific survival rate and provides a reference basis for patient diagnosis and prognosis evaluation.

The impact of local staging of prostate cancer determined on MRI or DRE at time of radical prostatectomy on progression-free survival: A Will Rogers phenomenon

INTRODUCTION

We aimed to test whether the current practice of using mpMRI stage might lead to a Will Rogers phenomenon with a stage migration compared to DRE in men undergoing radical prostatectomy.

MATERIAL AND METHODS

A total of 572 consecutive patients who underwent radical prostatectomy at a single institution (2007-2017) were included. Clinical stage using digital rectal examination was determined on table by the operating surgeon; mpMRI and pathological stage were recorded after tumor board review. Progression-free survival (PFS) was defined as no rising PSA, no adjuvant/salvage treatment, and no metastases or mortality. PFS was compared between groups and a model incorporating mpMRI into the EAU risk groups was created.

RESULTS

Median age was 63 years (IQR 58.5-67) and median PSA was 8.9 ng/ml (IQR 6.5-13.2). Using DRE stage, 20% were NCCN low risk, 43% were intermediate, and 37% high. Median follow-up was 48 months (IQR 22-73). Estimated PFS at 1, 3, and 5 years was 75%, 59%, and 54%, respectively. When comparing PFS between DRE and mpMRI stages, patients deemed T1 (P < 0.01) or T3 (P = 0.03) by mpMRI showed better outcomes than patients staged T1 or T3 by DRE. On univariable analysis lower risk for failure was seen for MRI T1 disease (HR 0.10 95%, CI 0.01-0.73, P = 0.02) or MRI T3 (HR 0.70, CI 0.51-0.97, P = 0.03). On multivariable analysis, only MRI T1 remained a significant predictor (HR 0.08, 95% CI 0.01-0.59, P = 0.01). The subsequent, modified EAU risk model using both DRE and mpMRI performed significantly better than the DRE model.

CONCLUSION

PFS based on mpMRI is not the same as DRE staging. Current risk groups which use DRE should be used with caution in whom local stage is based on mpMRI. Our modified EAU-risk categories can provide greater accuracy.

Introducing new plan evaluation indices for prostate dose painting IMRT plans based on apparent diffusion coefficient images

BACKGROUND

Dose painting planning would be more complicated due to different levels of prescribed doses and more complex evaluation with conventional plan quality indices considering uniform dose prescription. Therefore, we tried to introduce new indices for evaluating the dose distribution conformity and homogeneity of treatment volumes based on the tumoral cell density and relative volumes of each lesion in prostate IMRT.

METHODS

CT and MRI scans of 20 male patients having local prostate cancer were used for IMRT DP planning. Apparent diffusion coefficient (ADC) images were imported to a MATLAB program to identify lesion regions based on ADC values automatically. Regions with ADC values lower than 750 mm²/s and regions with ADC values higher than 750 and less than 1500 mm²/s were considered CTV_70Gy (clinical tumor volume with 70 Gy prescribed dose), and CTV_60Gy, respectively. Other regions of the prostate were considered as CTV_53Gy. New plan evaluation indices based on evaluating the homogeneity (IOE(H)), and conformity (IOE(C)) were introduced, considering the relative volume of each lesion and cellular density obtained from ADC images. These indices were compared with conventional homogeneity and conformity indices and IOEs without considering cellular density. Furthermore, tumor control probability (TCP) was calculated for each patient, and the relationship of the assessed indices were evaluated with TCP values.

RESULTS

IOE (H) and IOE (C) with considering cellular density had significantly lower values compared to conventional indices and IOEs without considering cellular density. (P < 0.05). TCP values had a stronger relationship with IOE(H) considering cell density (R² = -0.415), and IOE(C) without considering cell density (R² = 0.624).

CONCLUSION

IOE plan evaluation indices proposed in this study can be used for evaluating prostate IMRT dose painting plans. We suggested to consider cell densities in the IOE(H) calculation formula and it's appropriate to calculate IOE(C) without considering cell density values.

Deep Learning Reconstruction Enables Highly Accelerated Biparametric MR Imaging of the Prostate

BACKGROUND

Early diagnosis and treatment of prostate cancer (PCa) can be curative; however, prostate-specific antigen is a suboptimal screening test for clinically significant PCa. While prostate magnetic resonance imaging (MRI) has demonstrated value for the diagnosis of PCa, the acquisition time is too long for a first-line screening modality.

PURPOSE

To accelerate prostate MRI exams, utilizing a variational network (VN) for image reconstruction.

STUDY TYPE

Retrospective.

SUBJECTS

One hundred and thirteen subjects (train/val/test: 70/13/30) undergoing prostate MRI.

FIELD STRENGTH/SEQUENCE

3.0 T; a T2 turbo spin echo (TSE) T2-weighted image (T2WI) sequence in axial and coronal planes, and axial echo-planar diffusion-weighted imaging (DWI).

ASSESSMENT

Four abdominal radiologists evaluated the image quality of VN reconstructions of retrospectively under-sampled biparametric MRIs (bp-MRI), and standard bp-MRI reconstructions for 20 test subjects (studies). The studies included axial and coronal T2WI, DWI B50 seconds/mm² and B1000 seconds/mm (4-fold T2WI, 3-fold DWI), all of which were evaluated separately for image quality on a Likert scale (1: non-diagnostic to 5: excellent quality). In another 10 test subjects, three readers graded lesions on bp-MRI-which additionally included calculated B1500 seconds/mm² , and apparent diffusion coefficient map-according to the Prostate Imaging Reporting and Data System (PI-RADS v2.1), for both VN and standard reconstructions. Accuracy of PI-RADS ≥3 for clinically significant cancer was computed. Projected scan time of the retrospectively under-sampled biparametric exam was also computed.

STATISTICAL TESTS

One-sided Wilcoxon signed-rank test was used for comparison of image quality. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for lesion detection and grading. Generalized estimating equation with cluster effect was used to compare differences between standard and VN bp-MRI. A P-value of <0.05 was considered statistically significant.

RESULTS

Three of four readers rated no significant difference for overall quality between the standard and VN axial T2WI (Reader 1: 4.00 ± 0.56 (Standard), 3.90 ± 0.64 (VN) P = 0.33; Reader 2: 4.35 ± 0.74 (Standard), 3.80 ± 0.89 (VN) P = 0.003; Reader 3: 4.60 ± 0.50 (Standard), 4.55 ± 0.60 (VN) P = 0.39; Reader 4: 3.65 ± 0.99 (Standard), 3.60 ± 1.00 (VN) P = 0.38). All four readers rated no significant difference for overall quality between standard and VN DWI B1000 seconds/mm² (Reader 1: 2.25 ± 0.62 (Standard), 2.45 ± 0.75 (VN) P = 0.96; Reader 2: 3.60 ± 0.92 (Standard), 3.55 ± 0.82 (VN) P = 0.40; Reader 3: 3.85 ± 0.72 (Standard), 3.55 ± 0.89 (VN) P = 0.07; Reader 4: 4.70 ± 0.76 (Standard); 4.60 ± 0.73 (VN) P = 0.17) and three of four readers rated no significant difference for overall quality between standard and VN DWI B50 seconds/mm² (Reader 1: 3.20 ± 0.70 (Standard), 3.40 ± 0.75 (VN) P = 0.98; Reader 2: 2.85 ± 0.81 (Standard), 3.00 ± 0.79 (VN) P = 0.93; Reader 3: 4.45 ± 0.72 (Standard), 4.05 ± 0.69 (VN) P = 0.02; Reader 4: 4.50 ± 0.69 (Standard), 4.45 ± 0.76 (VN) P = 0.50). In the lesion evaluation study, there was no significant difference in the number of PI-RADS ≥3 lesions identified on standard vs. VN bp-MRI (P = 0.92, 0.59, 0.87) with similar sensitivity and specificity for clinically significant cancer. The average scan time of the standard clinical biparametric exam was 11.8 minutes, and this was projected to be 3.2 minutes for the accelerated exam.

DATA CONCLUSION

Diagnostic accelerated biparametric prostate MRI exams can be performed using deep learning methods in <4 minutes, potentially enabling rapid screening prostate MRI.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 5.

Impact of MRI/US fusion‐guided prostate biopsy on biopsy‐naïve patients: A single urologist’s experience

Objectives

To report our experience with imaging‐guided targeted prostate biopsy (IGTpBx) for patients undergoing initial prostate biopsy in a clinical setting.

Materials and methods

From July 2014 to February 2020, 305 men who had IGTpBx performed as their first prostate biopsy were enrolled. Two dedicated magnetic resonance imaging (MRI) radiologists segmented at least 1 region of interest (ROI) for each of these men using screening 1.5T MRI images. A single urologist employed the robotic‐assisted Artemis MRI/ultrasonography (US) fusion platform to obtain 2‐3 targeted samples from each ROI and additional random samples from the zones of the prostate outside the ROIs (a total of 12 zonal samples). Biopsy outcomes were categorized based on the Gleason score (GS) grade group (GG) as no cancer, favorable (GG < 3 or GS < 4 + 3), or clinically significant (GG ≥ 3 or GS ≥ 4 + 3) cancer.

Results

The overall cancer detection rate was 75%:31% clinically significant, 44% favorable, and 25% no cancer. These findings triggered active interventions in 176 (58%) patients. A prostate‐specific antigen (PSA) level of 0–4 ng/mL was detected in 39 (66%) of 59 patients (32 favorable, 7 significant), 4–10 ng/mL in 147 (77%) of 190 patients (85 favorable, 62 significant), and 10 ng/mL and over in 44 (80%) of 55 patients (17 favorable, 27 significant).

Conclusions

The tumor detection rate was 75% with IGTpBx in patients without a previous biopsy. In addition, about 42% of detected cancers were deemed clinically significant and led to active interventions. IGTpBx as a patient’s first prostate biopsy improves the detection of clinically significant prostate cancer when compared with historical data for random systematic prostate biopsy.

The diagnostic accuracy of multiparametric MRI for detection and localization of prostate cancer depends on the affected region

Objectives

To determine the diagnostic accuracy of 3T multiparametric magnetic resonance imaging (mpMRI) for detecting and locating prostate cancer (PCa) on Dickinson's 27-sector map, using histopathology specimens from radical prostatectomy (RP) as the reference standard.

Patients and methods

The authors studied a continuous series of 140 patients who underwent RP over three consecutive years. Prior to RP, all patients had mpMRI for detection and localization of PCa and further assessment by biopsy. To minimize the potential of disease progression, 25 patients were excluded because the interval between mpMRI and RP exceeded 6 months, which left 115 patients eligible for analysis. The mpMRI findings were reported using the Prostate Imaging-Reporting and Data System (PI-RADS) v2, considering PI-RADS ≥ 3 to indicate PCa. The histopathology findings from RP specimens were graded using the Gleason scoring system, considering Gleason ≥ 6 to indicate PCa. The location of the tumors was mapped on Dickinson's 27-sector map for both mpMRI and histopathology and compared by rigid sector-by-sector matching.

Results

The cohort of 115 patients eligible for analysis was aged 66.5 ± 6.0 years at RP. Of the 3105 sectors analyzed, there were 412 true positives (13%), 28 false positives (1%), 68 false negatives (2%), and 2597 true negatives (84%). Across the 27 sectors of the prostate, mpMRI sensitivity ranged from 50% to 100% and specificity from 96% to 100%, while PPV ranged from 50% to 100%, and NPV from 91% to 100%. For the anterior prostate, mpMRI had a sensitivity of 80% (CI, 71%-86%), specificity of 99% (CI, 99%-100%), PPV of 91% (CI, 83%-95%), and NPV of 99% (CI, 98%-99%). For the posterior prostate, mpMRI had a sensitivity of 88% (CI, 84%-91%), specificity of 98% (CI, 97%-99%), PPV of 94% (CI, 92%-96%), and NPV of 96% (CI, 94%-97%). Overall, mpMRI had a sensitivity of 86%, specificity of 99%, PPV of 94%, and NPV of 97%.

Conclusions

The accuracy of mpMRI in detecting and locating prostate tumors depends on the affected region, but its high NPV across all sectors suggests that negative findings may not need corroboration by other techniques.

Complications following local anaesthetic transperineal prostate biopsies without antibiotic prophylaxis: An institution’s experience

Objectives:

This study aimed to describe a UK institution’s experience with local anaesthetic (LA) transperineal (TP) prostate biopsies (PB), and to report 30-day complications following LATPPB, including a large cohort that did not receive antibiotic prophylaxis.

Patients and methods:

A prospective database of 313 consecutive patients undergoing LATPPB was maintained, describing patient and disease characteristics, and complications. From September 2019 to January 2020, antibiotic prophylaxis was given before LATPPB ( n=149). Following a change to routine care, from January 2020 to July 2020, prophylactic antibiotics were not given before LATPPB ( n=164). A comparative analysis was performed to determine complication rates following antibiotic prophylaxis discontinuation using electronic hospital and primary care records.

Results:

Patient and disease characteristics were comparable in antibiotic and non-antibiotic cohorts, and representative of PB and prostate cancer cohorts described in the urological literature. The infection-related complication rate was 0.32% across all patients, and 0% for those not receiving antibiotic prophylaxis. The overall complication rate was 0.64%, and 0.61% for those not receiving antibiotic prophylaxis. There were no severe (Clavien–Dindo 3–5) complications. The unplanned hospital admission rate was 0.64%.

Conclusion:

The complication rate after LATPPB was low, with no infection-related complications in patients who did not receive antibiotic prophylaxis. This provides further evidence supporting the discontinuation of routine prophylactic antibiotics before TPPB. Level of evidence: Level 2b.

Clinical validation of time reduction strategy in continuous step-and-shoot mode during SPECT acquisition

Background

The SwiftScan solution (General Electric Healthcare) combines a new low-energy high-resolution sensitivity collimator and a tomographic step-and-shoot continuous (SSC) mode acquisition. The purpose of this study is to determine whether SSC mode can be used in clinical practice with shorter examination times, while preserving image quality and ensuring accurate semi-quantification. Twenty bone scan and 10 lung scan studies were randomly selected over a period of 2 months. Three sets of image datasets were produced: step-and-shoot (SS) acquisition, simulated 25% count reduction using the Poisson resampling method (SimSS), and SimSS continuous acquisition (SimSSC), where SimSS was summed with counts acquired during detector head rotation. Visual assessment (5-point Likert scale, 2 readers) and semi-quantitative evaluation (50 focal uptake from 10 bone studies), assessed by SUV_mean, coefficient of variation (COV), and contrast-to-noise ratio (CNR), were performed using t test and Bland-Altman analysis.

Results

Intra-reader agreement was substantial for reader 1 (k = 0.71) and for reader 2 (k = 0.61). Inter-reader agreement was substantial for SS set (k = 0.93) and moderate for SimSSC (k = 0.52). Bland-Altman analysis showed a good interchangeability of SS and SimSSC SUV values. The mean CNR between SS and SimSSC was not significantly different: 42.9 ± 43.7 [23.7–62.1] vs. 43.1 ± 46 [22.9–63.3] (p = 0.46), respectively. COV values, assessing noise level, did not deviate significantly between SS and SimSSC: 0.20 ± 0.08 [0.18–0.23] vs. 0.21 ± 0.08, [0.18–0.23] (p = 0.15), respectively, whereas a significant difference was demonstrated between SS and SimSS: 0.20 ± 0.08 [0.18–0.23] vs. 0.23 ± 0.09 [0.20–0.25] (p < 0.0001), respectively.

Conclusions

SSC mode acquisition decreases examination time by approximately 25% in bone and lung SPECT/CT studies compared to SS mode (~ 2 min per single-bed SPECT), without compromising image quality and signal quantification. This SPECT sensitivity improvement also offers the prospect of more comfortable exams, with less motion artifacts, especially in painful or dyspneic patients.

Role of MRI for the detection of prostate cancer

The use of multiparametric MRI has been hastened under expanding, novel indications for its use in the diagnostic and management pathway of men with prostate cancer. This has helped drive a large body of the literature describing its evolving role over the last decade. Despite this, prostate cancer remains the only solid organ malignancy routinely diagnosed with random sampling. Herein, we summarize the components of multiparametric MRI and interpretation, and present a critical review of the current literature supporting is use in prostate cancer detection, risk stratification, and management.

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

BACKGROUND

Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting.

MATERIALS AND METHODS

Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value.

RESULTS

Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56).

CONCLUSIONS

68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis.

Characterization of B0-field fluctuations in prostate MRI

Multi-parametric MRI is increasingly used for prostate cancer detection. Improving information from current sequences, such as T2-weighted and diffusion-weighted (DW) imaging, and additional sequences, such as magnetic resonance spectroscopy (MRS) and chemical exchange saturation transfer (CEST), may enhance the performance of multi-parametric MRI. The majority of these techniques are sensitive to B0-field variations and may result in image distortions including signal pile-up and stretching (echo planar imaging (EPI) based DW-MRI) or unwanted shifts in the frequency spectrum (CEST and MRS). Our aim is to temporally and spatially characterize B0-field changes in the prostate. Ten male patients are imaged using dual-echo gradient echo sequences with varying repetitions on a 3 T scanner to evaluate the temporal B0-field changes within the prostate. A phantom is also imaged to consider no physiological motion. The spatial B0-field variations in the prostate are reported as B0-field values (Hz), their spatial gradients (Hz/mm) and the resultant distortions in EPI based DW-MRI images (b-value = 0 s/mm2 and two oppositely phase encoded directions). Over a period of minutes, temporal changes in B0-field values were ≤19 Hz for minimal bowel motion and ≥30 Hz for large motion. Spatially across the prostate, the B0-field values had an interquartile range of ≤18 Hz (minimal motion) and ≤44 Hz (large motion). The B0-field gradients were between -2 and 5 Hz/mm (minimal motion) and 2 and 12 Hz/mm (large motion). Overall, B0-field variations can affect DW, MRS and CEST imaging of the prostate.

Stereotactic radiotherapy with focal boost for intermediate and high-risk prostate cancer: Initial results of the SPARC trial

INTRODUCTION

Dose escalation to dominant intraprostatic lesions (DILs) is a novel method to increase the therapeutic ratio in localised prostate cancer. The Stereotactic Prostate Augmented Radiotherapy with Cyberknife (SPARC) trial was designed to determine the feasibility of a focal boost defined with multiparametric magnetic resonance imaging (mpMRI) using stereotactic ablative body radiotherapy (SABR).

MATERIALS AND METHODS

Patients were included with newly diagnosed intermediate to high risk prostate cancer with at least one of: Gleason score 4 + 3, stage T3a, or PSA > 20 ng/ml. Visible disease on mpMRI was mandatory and up to 2 separate nodules were allowed. All patients received androgen deprivation. Patients received 36.25 Gy in 5 fractions using CyberKnife® and the DIL received a simultaneous boost to a maximum of 47.5 Gy, as allowed by OAR constraints. Genitourinary (GU) and gastrointestinal (GI) toxicity was reported using the RTOG scoring criteria. International Index of Erectile Function (IIEF) and EQ-5D global health scores were regularly captured.

RESULTS

An interim safety analysis was performed on the first 8 patients, recruited between July 2013 and December 2015. Median follow up was 56 months (range 50-74). Median D95 values for the prostate PTV and boost volume were 36.55 Gy (range 35.87-36.99) and 46.62 Gy (range 44.85-48.25) respectively. Of the dose constraints, 10/80 were not achieved but all were minor dose variations. Grade 2+ acute GU and GI toxicities were 37.5% respectively while grade 2+ late GU and GI toxicities were 12.5% and 0% respectively. IIEF and quality of life scores recovered over time and all patients remain in biochemical remission.

CONCLUSION

The first patients have been successfully treated with prostate SABR and focal boost on the SPARC trial, with excellent adherence to the planning protocol. Toxicity and efficacy results are promising and further recruitment is underway.

Ultrasound elastography in characterization of prostatic lesions: correlation with histopathological findings

OBJECTIVE

Ultrasound elastography is increasingly used in the diagnosis of prostate cancer, however results are heterogeneous. We correlate in a large sample-size prospective study the accuracy of elastography, aiming to settle an accurate cut-off point for diagnosis and possibility of use as a screening tool.

METHODS

Prospective study that included 120 patients with mean age 59.5 ± 9.8 years, showing enlarged prostate by clinical examination with prostate-specific antigen >4 ng ml-1.The study was done using high frequency high resolution endorectal probe with real time tissue elastography.Grayscale ultrasound examination was done first with Doppler followed by elastography color-coded map and strain ratio measurement. Then, transrectal ultrasound-guided core biopsy was done from suspicious areas detected by elastography (totally or partly stiff by color-coded map or with relative increased strain ratio), besides standard six-quadrant core biopsy samples.

RESULTS

There was statistically significant difference (p < 0.001) regarding strain ratio in benign and malignant lesions. Strain ratio showed significant proportionate correlation with prostate-specific antigen level and Gleason pathological score, while no significant correlation noted with the age or the prostatic volume. A strain ratio with a cut-off value of 1.9 showed a sensitivity of 100%, specificity 93.8%, positive predictive value of 79.3%, negative predictive value 100 and 95% accuracy in differentiating between malignant and benign lesions.

CONCLUSION

Strain ratio improves the detection of prostatic cancer with high sensitivity (100%) and high negative predictive value (100%).

ADVANCES IN KNOWLEDGE

Different prostatic lesions are mostly similar in grayscale ultrasound.Imaging plays an important role in differentiation of prostatic nodules.Ultrasound elastography may play an important role in distinguishing benign from malignant nodules.

Applications of Artificial Intelligence to Prostate Multiparametric MRI (mpMRI): Current and Emerging Trends

Prostate carcinoma is one of the most prevalent cancers worldwide. Multiparametric magnetic resonance imaging (mpMRI) is a non-invasive tool that can improve prostate lesion detection, classification, and volume quantification. Machine learning (ML), a branch of artificial intelligence, can rapidly and accurately analyze mpMRI images. ML could provide better standardization and consistency in identifying prostate lesions and enhance prostate carcinoma management. This review summarizes ML applications to prostate mpMRI and focuses on prostate organ segmentation, lesion detection and segmentation, and lesion characterization. A literature search was conducted to find studies that have applied ML methods to prostate mpMRI. To date, prostate organ segmentation and volume approximation have been well executed using various ML techniques. Prostate lesion detection and segmentation are much more challenging tasks for ML and were attempted in several studies. They largely remain unsolved problems due to data scarcity and the limitations of current ML algorithms. By contrast, prostate lesion characterization has been successfully completed in several studies because of better data availability. Overall, ML is well situated to become a tool that enhances radiologists' accuracy and speed.

Radiological semantics discriminate clinically significant grade prostate cancer

Background

Identification of imaging traits to discriminate clinically significant prostate cancer is challenging due to the multi focal nature of the disease. The difficulty in obtaining a consensus by the Prostate Imaging and Data Systems (PI-RADS) scores coupled with disagreements in interpreting multi-parametric Magnetic Resonance Imaging (mpMRI) has resulted in increased variability in reporting findings and evaluating the utility of this imaging modality in detecting clinically significant prostate cancer. This study assess the ability of radiological traits (semantics) observed on multi-parametric Magnetic Resonance images (mpMRI) to discriminate clinically significant prostate cancer.

Methods

We obtained multi-parametric MRI studies from 103 prostate cancer patients with 167 targeted biopsies from a single institution. The study was approved by our Institutional Review Board (IRB) for retrospective analysis. The biopsy location had been identified and marked by a clinical radiologist for targeted biopsy based on initial study interpretation. Using the target locations, two study radiologists independently re-evaluated the scans and scored 16 semantic traits on a point scale (up to 5 levels) based on mpMRI images. The semantic traits describe size, shape, and border characteristics of the prostate lesion, as well as presence of disease around lymph nodes (lymphadenopathy). We built a linear classifier model on these semantic traits and related to pathological outcome to identify clinically significant tumors (Gleason Score ≥ 7). The discriminatory ability of the predictors was tested using cross validation method randomly repeated and ensemble values were reported. We then compared the performance of semantic predictors with the PI-RADS predictors.

Results

We found several semantic features individually discriminated high grade Gleason score (ADC-intensity, Homogeneity, early-enhancement, T2-intensity and extraprostatic extention), these univariate predictors had an average area under the receiver operator characteristics (AUROC) ranging from 0.54 to 0.68. Multivariable semantic predictors with three features (ADC-intensity; T2-intensity, enhancement homogenicity) had an average AUROC of 0.7 [0.43, 0.94]. The PI-RADS based predictor had average AUROC of 0.6 [0.47, 0.75].

Conclusion

We find semantics traits are related to pathological findings with relatively higher reproducibility between radiologists. Multivariable predictors formed on these traits shows higher discriminatory ability compared to PI-RADS scores.

Targeted biopsy of the prostate: does this result in improvement in detection of high-grade cancer or the occurrence of the Will Rogers phenomenon?

OBJECTIVE

To investigate whether patients with Gleason 3 + 4 cancer on transrectal biopsy are upgraded after undergoing transperineal magnetic resonance imaging (MRI)-targeted biopsy and whether this has implications for current clinical practice.

PATIENTS AND METHODS

In this retrospective analysis we examined 107 consecutive patients presenting at a single tertiary referral centre (July 2012 to July 2016) with prostate cancer of Gleason score 3 + 4 on transrectal ultrasonography (TRUS)-guided systematic non-targeted biopsy who then underwent a multiparametric MRI followed by MRI-targeted transperineal prostate biopsy for accurate risk stratification and localization.

RESULTS

The patients' mean (sd) age was 67.0 (8.0) years, and they had a median (interquartile range) PSA concentration of 6.2 (4.7-9.6) ng/mL. Of the 107 patients, 84 (78.5%) had Gleason 3 + 4 on both transrectal systematic biopsy and transperineal MRI-targeted biopsy. Nineteen patients (17.8%) were upgraded to Gleason 4 + 3, three patients (3.0%) to Gleason 4 + 4 and one patient (1.0%) to Gleason 4 + 5. These differences were significant (P = 0.0006). Likewise, 23/107 patients (22%) had higher-risk disease based on their targeted biopsies.

CONCLUSION

The use of targeted biopsy in men with impalpable cancer, ultimately upgraded one in five patients from favourable-intermediate- to unfavourable-intermediate-risk disease or worse. This has significant clinical implications for men considering active surveillance or radical treatment. Our risk calculators must now be validated using these data from targeted biopsy as the technique becomes widely adopted.

GRASP-Pro: imProving GRASP DCE-MRI through self-calibrating subspace-modeling and contrast phase automation

PURPOSE

To propose a highly accelerated, high-resolution dynamic contrast-enhanced MRI (DCE-MRI) technique called GRASP-Pro (golden-angle radial sparse parallel imaging with imProved performance) through a joint sparsity and self-calibrating subspace constraint with automated selection of contrast phases.

METHODS

GRASP-Pro reconstruction enforces a combination of an explicit low-rank subspace-constraint and a temporal sparsity constraint. The temporal basis used to construct the subspace is learned from an intermediate reconstruction step using the low-resolution portion of radial k-space, which eliminates the need for generating the basis using auxiliary data or a physical signal model. A convolutional neural network was trained to generate the contrast enhancement curve in the artery, from which clinically relevant contrast phases are automatically selected for evaluation. The performance of GRASP-Pro was demonstrated for high spatiotemporal resolution DCE-MRI of the prostate and was compared against standard GRASP in terms of overall image quality, image sharpness, and residual streaks and/or noise level.

RESULTS

Compared to GRASP, GRASP-Pro reconstructed dynamic images with enhanced sharpness, less residual streaks and/or noise, and finer delineation of the prostate without prolonging reconstruction time. The image quality improvement reached statistical significance (P < 0.05) in all the assessment categories. The neural network successfully generated contrast enhancement curves in the artery, and corresponding peak enhancement indexes correlated well with that from the manual selection.

CONCLUSION

GRASP-Pro is a promising method for rapid and continuous DCE-MRI. It enables superior reconstruction performance over standard GRASP and allows reliable generation of artery enhancement curve to guide the selection of desired contrast phases for improving the efficiency of GRASP MRI workflow.

Multiparametric MRI to improve detection of prostate cancer compared with transrectal ultrasound-guided prostate biopsy alone: the PROMIS study

BACKGROUND

Men with suspected prostate cancer usually undergo transrectal ultrasound (TRUS)-guided prostate biopsy. TRUS-guided biopsy can cause side effects and has relatively poor diagnostic accuracy. Multiparametric magnetic resonance imaging (mpMRI) used as a triage test might allow men to avoid unnecessary TRUS-guided biopsy and improve diagnostic accuracy.

OBJECTIVES

To (1) assess the ability of mpMRI to identify men who can safely avoid unnecessary biopsy, (2) assess the ability of the mpMRI-based pathway to improve the rate of detection of clinically significant (CS) cancer compared with TRUS-guided biopsy and (3) estimate the cost-effectiveness of a mpMRI-based diagnostic pathway.

DESIGN

A validating paired-cohort study and an economic evaluation using a decision-analytic model.

SETTING

Eleven NHS hospitals in England.

PARTICIPANTS

Men at risk of prostate cancer undergoing a first prostate biopsy.

INTERVENTIONS

Participants underwent three tests: (1) mpMRI (the index test), (2) TRUS-guided biopsy (the current standard) and (3) template prostate mapping (TPM) biopsy (the reference test).

MAIN OUTCOME MEASURES

Diagnostic accuracy of mpMRI, TRUS-guided biopsy and TPM-biopsy measured by sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) using primary and secondary definitions of CS cancer. The percentage of negative magnetic resonance imaging (MRI) scans was used to identify men who might be able to avoid biopsy.

RESULTS

Diagnostic study - a total of 740 men were registered and 576 underwent all three tests. According to TPM-biopsy, the prevalence of any cancer was 71% [95% confidence interval (CI) 67% to 75%]. The prevalence of CS cancer according to the primary definition (a Gleason score of ≥ 4 + 3 and/or cancer core length of ≥ 6 mm) was 40% (95% CI 36% to 44%). For CS cancer, TRUS-guided biopsy showed a sensitivity of 48% (95% CI 42% to 55%), specificity of 96% (95% CI 94% to 98%), PPV of 90% (95% CI 83% to 94%) and NPV of 74% (95% CI 69% to 78%). The sensitivity of mpMRI was 93% (95% CI 88% to 96%), specificity was 41% (95% CI 36% to 46%), PPV was 51% (95% CI 46% to 56%) and NPV was 89% (95% CI 83% to 94%). A negative mpMRI scan was recorded for 158 men (27%). Of these, 17 were found to have CS cancer on TPM-biopsy. Economic evaluation - the most cost-effective strategy involved testing all men with mpMRI, followed by MRI-guided TRUS-guided biopsy in those patients with suspected CS cancer, followed by rebiopsy if CS cancer was not detected. This strategy is cost-effective at the TRUS-guided biopsy definition 2 (any Gleason pattern of ≥ 4 and/or cancer core length of ≥ 4 mm), mpMRI definition 2 (lesion volume of ≥ 0.2 ml and/or Gleason score of ≥ 3 + 4) and cut-off point 2 (likely to be benign) and detects 95% (95% CI 92% to 98%) of CS cancers. The main drivers of cost-effectiveness were the unit costs of tests, the improvement in sensitivity of MRI-guided TRUS-guided biopsy compared with blind TRUS-guided biopsy and the longer-term costs and outcomes of men with cancer.

LIMITATIONS

The PROstate Magnetic resonance Imaging Study (PROMIS) was carried out in a selected group and excluded men with a prostate volume of > 100 ml, who are less likely to have cancer. The limitations in the economic modelling arise from the limited evidence on the long-term outcomes of men with prostate cancer and on the sensitivity of MRI-targeted repeat biopsy.

CONCLUSIONS

Incorporating mpMRI into the diagnostic pathway as an initial test prior to prostate biopsy may (1) reduce the proportion of men having unnecessary biopsies, (2) improve the detection of CS prostate cancer and (3) increase the cost-effectiveness of the prostate cancer diagnostic and therapeutic pathway. The PROMIS data set will be used for future research; this is likely to include modelling prognostic factors for CS cancer, optimising MRI scan sequencing and biomarker or translational research analyses using the blood and urine samples collected. Better-quality evidence on long-term outcomes in prostate cancer under the various management strategies is required to better assess cost-effectiveness. The value-of-information analysis should be developed further to assess new research to commission.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16082556 and NCT01292291.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 39. See the NIHR Journals Library website for further project information. This project was also supported and partially funded by the NIHR Biomedical Research Centre at University College London (UCL) Hospitals NHS Foundation Trust and UCL and by The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research Biomedical Research Centre and was co-ordinated by the Medical Research Council's Clinical Trials Unit at UCL (grant code MC_UU_12023/28). It was sponsored by UCL. Funding for the additional collection of blood and urine samples for translational research was provided by Prostate Cancer UK.

Increasing Utilization of Multiparametric Magnetic Resonance Imaging in Prostate Cancer Active Surveillance

OBJECTIVE

To characterize the use of multiparametric magnetic resonance imaging (mpMRI) in male Medicare beneficiaries electing active surveillance for prostate cancer. mpMRI has emerged as a tool that may improve risk-stratification and decrease repeated biopsies in men electing active surveillance. However, the extent to which mpMRI has been implemented in active surveillance has not been established.

METHODS

Using Surveillance, Epidemiology, and End Results registry data linked to Medicare claims data, we identified men with localized prostate cancer diagnosed between 2008 and 2013 and managed with active surveillance. We classified men into 2 treatment groups: active surveillance without mpMRI and active surveillance with mpMRI. We then fit a multivariable logistic regression models to examine changing mpMRI utilization over time, and factors associated with the receipt of mpMRI.

RESULTS

We identified 9467 men on active surveillance. Of these, 8178 (86%) did not receive mpMRI and 1289 (14%) received mpMRI. The likelihood of receiving mpMRI over the entire study period increased by 3.7% (P = .004). On multivariable logistic regression, patients who were younger, white, had lower comorbidity burden, lived in the northeast and west, had higher incomes and lived in more urban areas had greater odds of receiving mpMRI (all P < .05).

CONCLUSION

From 2008 to 2013, use of mpMRI in active surveillance increased gradually but significantly. Receipt of mpMRI among men on surveillance for prostate cancer varied significantly across demographic, geographic, and socioeconomic strata. Going forward, studies should investigate causes for this variation and define ideal strategies for equitable, cost-effective dissemination of mpMRI technology.

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

CONTEXT

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

OBJECTIVE

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

PATIENT SUMMARY

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

Magnetic resonance imaging/transrectal ultrasound fusion-targeted prostate biopsy using three-dimensional ultrasound-based organ-tracking technology: Initial experience in Japan

OBJECTIVE

To evaluate the impact of magnetic resonance imaging/transrectal ultrasound fusion-targeted prostate biopsy on the diagnosis of clinically significant prostate cancer using real-time three-dimensional ultrasound-based organ-tracking technology.

METHODS

The present study was a retrospective review of 262 consecutive patients with prostate-specific antigen of 7.1 ng/mL (interquartile range 4.0-19.8). All patients received pre-biopsy magnetic resonance imaging and had a suspicious lesion for clinically significant prostate cancer. All patients underwent a combination of systematic biopsy (6 cores) and three-dimensional ultrasound-based magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (2 cores). The positive rate of any cancer, positive rate of clinically significant prostate cancer, Gleason score and maximum cancer core length were compared between systematic biopsy versus magnetic resonance imaging/transrectal ultrasound fusion-targeted prostate biopsy.

RESULTS

Overall, the positive rate of any cancer per patient was 61% (160/262) in systematic biopsy versus 79% (207/262) in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P < 0.0001); and that of clinically significant prostate cancer per patient was 46% (120/262) in systematic biopsy versus 70% (181/262) in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P < 0.0001). The positive rate of any cancer per core was 21.7% (330/1523) in systematic biopsy versus 68.6% (406/592) in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P < 0.0001), and that of clinically significant prostate cancer per core was 12.7% (193/1423) in systematic biopsy versus 60.3% (357/592) in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P < 0.0001). Adding systematic biopsy leads to 13 more cancer cases (5%). The distribution of Gleason score (6/7/8/9/10) was 59/71/23/6/1 in systematic biopsy versus 48/105/36/15/2 in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P = 0.005). The maximum cancer core length was 5 mm (0.5-16) in systematic biopsy versus 8 mm (1-19 mm) in magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy (P < 0.0001).

CONCLUSIONS

Three-dimensional ultrasound-based magnetic resonance imaging/transrectal ultrasound fusion-targeted biopsy seems to be associated with a higher detection rate of clinically significant prostate cancer, with fewer cores than systematic random biopsy. However, significant cancer can still be detected by the systematic technique only. A combination of systematic biopsy with the targeted biopsy technique would avoid the underdiagnosis of clinically significant prostate cancer.

VERDICT-AMICO: Ultrafast fitting algorithm for non-invasive prostate microstructure characterization

VERDICT (vascular, extracellular and restricted diffusion for cytometry in tumours) estimates and maps microstructural features of cancerous tissue non-invasively using diffusion MRI. The main purpose of this study is to address the high computational time of microstructural model fitting for prostate diagnosis, while retaining utility in terms of tumour conspicuity and repeatability. In this work, we adapt the accelerated microstructure imaging via convex optimization (AMICO) framework to linearize the estimation of VERDICT parameters for the prostate gland. We compare the original non-linear fitting of VERDICT with the linear fitting, quantifying accuracy with synthetic data, and computational time and reliability (performance and precision) in eight patients. We also assess the repeatability (scan-rescan) of the parameters. Comparison of the original VERDICT fitting versus VERDICT-AMICO showed that the linearized fitting (1) is more accurate in simulation for a signal-to-noise ratio of 20 dB; (2) reduces the processing time by three orders of magnitude, from 6.55 seconds/voxel to 1.78 milliseconds/voxel; (3) estimates parameters more precisely; (4) produces similar parametric maps and (5) produces similar estimated parameters with a high Pearson correlation between implementations, r2  > 0.7. The VERDICT-AMICO estimates also show high levels of repeatability. Finally, we demonstrate that VERDICT-AMICO can estimate an extra diffusivity parameter without losing tumour conspicuity and retains the fitting advantages. VERDICT-AMICO provides microstructural maps for prostate cancer characterization in seconds.

Clinical significance and predictors of oncologic outcome after radical prostatectomy for invisible prostate cancer on multiparametric MRI

Background

The objective of our study was to evaluate the clinical significance of invisible prostate cancer (iPCa) on multiparametric magnetic resonance imaging (mpMRI) by analyzing clinical parameters and oncologic outcomes.

Methods

We retrospectively reviewed the records of patients treated with radical prostatectomy (RP) from 2010 to 2015 at our institution. Before RP, all patients were confirmed to have prostate cancer based on prostate biopsy. We excluded patients who underwent neoadjuvant therapy. Additionally, we excluded patients who had incomplete mpMRI based on PI-RADS (Prostate Imaging Reporting and Data System). iPCa was defined as having no grade 3 or higher region of interests using a scoring system established by PI-RADS without limitations on interpretation from mpMRI by radiologists. We selected patients with iPCa using this protocol. We analyzed data using univariate and multivariate cox regression analysis, logistic analysis, Kaplan-Meier curves, and receiver operator characteristic curves to predict biochemical recurrence (BCR).

Results

A total of 213 patients with iPCa were selected according to the patient selection protocol. Among them, pathological findings showed that Gleason score (GS) G6, G7 and ≥ G8 were present in 115 cases (54.0%), 78 cases (36.6%), and 20 cases (9.4%), respectively. Further, extracapsular extension (ECE), positive surgical margins (PSM), and lymphovascular invasion (LVI) were present in 28 (13.1%), 18 (8.5%), and 3 cases (1.4%), respectively. Seminal vesicle invasion (SVI) was observed in one case (0.5%). During a median follow-up time of 51 months, BCR was observed 29 cases. Adverse pathology (AP) was defined as GS ≥8, ECE, SVI and LVI. AP and prostate specific antigen (PSA) were significantly associated with BCR. Moreover, PSA > 6.2 ng/ml was suggested as a cut-off value for predicting BCR.

Conclusions

In our results, cases of iPCa had clinically significant PCa, and AP and poor prognosis were also observed in some. Additionally, we found that PSA is the most clinically reliable predictor of oncologic outcome. We suggest that active treatment and diagnosis should be considered for patients with iPCa with PSA > 6.2 ng/ml.

Prostate cancer diagnostic pathway: Is a one-stop cognitive MRI targeted biopsy service a realistic goal in everyday practice? A pilot cohort in a tertiary referral centre in the UK

OBJECTIVES

To evaluate the feasibility of a novel multiparametric MRI (mpMRI) and cognitive fusion transperineal targeted biopsy (MRTB) led prostate cancer (PCa) diagnostic service with regard to cancer detection and reducing time to diagnosis and treatment.

DESIGN

Consecutive men being investigated for possible PCa under the UK 2-week wait guidelines.

SETTING

Tertiary referral centre for PCa in the UK.

PARTICIPANTS

Men referred with a raised prostate-specific antigen (PSA) or abnormal digital rectal examination between February 2015 and March 2016 under the UK 2-week rule guideline.

INTERVENTIONS

An mpMRI was performed prior to patients attending clinic, on the same day. If required, MRTB was offered. Results were available within 48 hours and discussed at a specialist multidisciplinary team meeting. Patients returned for counselling within 7 days PRIMARY AND SECONDARY OUTCOME MEASURES: Outcome measures in this regard included the time to diagnosis and treatment of patients referred with a suspicion of PCa. Quality control outcome measures included clinically significant and total cancer detection rates.

RESULTS

112 men were referred to the service. 111 (99.1%) underwent mpMRI. Median PSA was 9.4 ng/mL (IQR 5.6-21.0). 87 patients had a target on mpMRI with 25 scoring Likert 3/5 for likelihood of disease, 26 4/5 and 36 5/5.57 (51%) patients received a local anaesthetic, Magnetic resonance imaging targeted biopsy (MRTB). Cancer was detected in 45 (79%). 43 (96%) had University College London definition 2 disease or greater. The times to diagnosis and treatment were a median of 8 and 20 days, respectively.

CONCLUSIONS

This approach greatly reduces the time to diagnosis and treatment. Detection rates of significant cancer are high. Similar services may be valuable to patients with a potential diagnosis of PCa.

50-Gy Stereotactic Body Radiation Therapy to the Dominant Intraprostatic Nodule: Results From a Phase 1a/b Trial

PURPOSE

Although localized prostate cancer (PCa) is multifocal, the dominant intraprostatic nodule (DIN) is responsible for disease progression after radiation therapy. PCa expresses antigens that could be recognized by the immune system. We therefore hypothesized that stereotactic dose escalation to the DIN is safe, may increase local control, and may initiate tumor-specific immune responses.

PATIENTS AND METHODS

Patients with localized PCa were treated with stereotactic extreme hypofractionated doses of 36.25 Gy in 5 fractions to the whole prostate while simultaneously escalating doses to the magnetic resonance image-visible DIN (45 Gy, 47.5 Gy, and 50 Gy in 5 fractions). The phase 1a part was designed to determine the recommended phase 1b dose in a "3 + 3" cohort-based, dose-escalation design. The primary endpoint was dose-limiting toxicities defined as ≥grade 3 gastrointestinal (GI) or genitourinary (GU) toxicity (or both) by National Cancer Institute Common Terminology Criteria for Adverse Events (version 4) up to 90 days after the first radiation fraction. The secondary endpoints were prostate-specific antigen kinetics, quality of life (QoL), and blood immunologic responses.

RESULTS

Nine patients were treated in phase 1a. No dose-limiting toxicities were observed at either level, and therefore the maximum tolerated dose was not reached. Further characterization of tolerability, efficacy, and immunologic outcomes was conducted in the subsequent 11 patients irradiated at the highest dose level (50 Gy) in the phase 1b expansion cohort. Toxicity was 45% and 25% for grades 1 and 2 GU, and 20% and 5% for grades 1 and 2 GI, respectively. No grade 3 or worse toxicity was reported. The average (±standard error of the mean) of the QoL assessments at baseline and at 3-month posttreatment were 0.8 (±0.8) and 3.5 (±1.5) for the bowel (mean difference, 2.7; 95% confidence interval, 0.1-5), and 6.4 (±0.8) and 7.27 (±0.9) for the International Prostate Symptom Score (mean difference, 0.87; 95% confidence interval, 0.3-1.9), respectively. A subset of patients developed antigen-specific immune responses against prostate-specific membrane antigen (n = 2), prostatic acid phosphatase (n = 1), prostate stem cell antigen (n = 4), and prostate-specific antigen (n = 2).

CONCLUSIONS

Irradiation of the whole prostate with 36.25 Gy in 5 fractions and dose escalation to 50 Gy to the DIN was tolerable and determined as the recommended phase 1b dose. This treatment has promising antitumor activity, which will be confirmed by the ongoing phase 2 part. Preliminary QoL analysis showed minimal impact in GU, GI, and sexual domains. Stereotactic irradiation induced antigen-specific immune responses in a subset of patients.

Objective value on Apparent diffusion coefficient (ADC) map to categorize the intensity of diffusion-weighted imaging (DWI) restriction for prostate cancer detection on multiparametric prostate MRI

PURPOSE

To identify objective and subjective criteria on multiparametric prostate MRI that can be helpful for prostate cancer detection.

MATERIALS AND METHODS

Retrospective study, IRB approved, including 122 patients who had suspicious lesion on MRI and who underwent prostate biopsy with ultrasonography (US)/MRI imaging fusion. There were 60 patients with positive biopsies and 62 with negative biopsies. MRI of these patients were randomized and evaluated independently by two blinded radiologists. The following variables were analyzed in each lesion: morphology, contours, T2 signal, diffusion restriction (subjective impression and objective values), hyper-enhancement, contact with transition zone or prostatic contour, prostatic contour retraction, Likert and PIRADS classification.

RESULTS

Apparent diffusion coefficient (ADC) value was the best predictor of positivity for prostate cancer, with mean value of 1.08 (SD 0.20) and 1.09 mm2/sec (SD 0.24) on negative biopsies and 0.81 (SD 0.22) and 0.84 mm2/sec (SD 0.22) on positive biopsies for readers 1 and 2, respectively (p < 0.001 in both analysis). For the others categorical variables evaluated the best AUC for reader 1 was subjective intensity of diffusion restriction (AUC of 0.74) and for reader 2 was hyper-enhancement (AUC of 0.65), all inferior comparing to the value of ADC map. Interobserver agreement ranged from 0.13 to 0.75, poor in most measurements, and good or excellent (kappa > 0.6) only in lesion size and ADC values.

CONCLUSIONS

Diffusion restriction with lower ADC-values is the best parameter to predict cancer on MRI prior to biopsy. Efforts to establish an ADC cutoff value would improve cancer detection, especially for less experience reader.

Multiparametric MRI reporting using Prostate Imaging Reporting and Data System version 2.0 (PI-RADSv2) retains clinical efficacy in a predominantly post-biopsy patient population

Objective

To evaluate the efficacy of multiparametric magnetic resonance imaging (mp-MRI) using Prostate Imaging Reporting and Data System version 2.0 (PI-RADSv2) definitions in detecting organ-confined prostate cancer.

Methods

All patients who underwent radical prostatectomy between January 1, 2014 and December 30, 2014 were identified. All underwent mp-MRI within 180 days before surgery. Those with prior pelvic irradiation or androgen deprivation therapy were excluded. Fully embedded, whole-mount histopathology was centrally reviewed and correlated with imaging for tumour location, Gleason score (GS) and stage.

Results

There were 39 patients included, of which 35 (90%) had mp-MRI done post-biopsy. A total of 93 cancer foci were identified on whole-mount pathology, of which mp-MRI detected 63 (68%). Of those detected by mp-MRI, 14 were PI-RADS 3 (n = 6 for GS 6, n = 8 for GS 7, no GS ≥ 8) and 49 were PI-RADS 4–5 (n = 7 for GS 6, n = 33 for GS 7, and n = 9 for GS ≥ 8). There were 30 (32%) cancer foci missed by mp-MRI (n = 15 for GS 6, n = 13 for GS 7 and n = 2 for GS ≥ 8). A lesion classified as PI-RADS 4–5 predicted a higher grade cancer on pathology as compared to PI-RADS 3 (for GS 7 lesions, odds ratio [OR] = 3.53, 95% CI: 0.93–13.45, p = 0.064). The mp-MRI size detection limit was 20 mm² and 100 mm² for 50% and 75% probability of cancer, respectively. In associating with radiological and pathologic stage, the weighted Kappa value was 0.69 (p < 0.0001). The sensitivity and positive predictive values for this study were 68% (95% CI: 57%–77%) and 78% (95% CI: 67%–86%), respectively.

Conclusion

In this predominantly post-biopsy cohort, mp-MRI using PI-RADSv2 reporting has a reasonably high diagnostic accuracy in detecting clinically significant prostate cancer.

Predicting Benign Prostate Pathology on Magnetic Resonance Imaging/Ultrasound Fusion Biopsy in Men with a Prior Negative 12-core Systematic Biopsy: External Validation of a Prognostic Nomogram

BACKGROUND

Magnetic resonance imaging (MRI) of the prostate after a prior negative biopsy may reduce the need for unnecessary repeat biopsies.

OBJECTIVE

To externally validate a previously developed nomogram predicting benign prostate pathology on MRI/ultrasound (US) fusion-targeted biopsy in men with a Prostate Imaging Reporting and Data System (PI-RADS) 3-5 region of interest and a prior negative 12-core systematic biopsy, and update this nomogram to improve its performance.

DESIGN, SETTING, AND PARTICIPANTS

A total of 2063 men underwent MRI/US fusion-targeted biopsy from April 2012 to September 2017; 104 men with a negative systematic biopsy followed by MRI-US fusion-targeted biopsy of a PI-RADS 3-5 region of interest (58%) met the study inclusion criteria.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

An MRI-based nomogram that had previously been developed in a multi-institutional clinical setting was externally validated. Predictive characteristics were age, prostate volume, MRI PI-RADS score, and prostate-specific antigen (PSA). Bayesian logistic regression was used to update the previous model.

RESULTS AND LIMITATIONS

Median age of the external validation cohort was 68 yr, PSA was 7.2ng/ml, and biopsy confirmed benign pathology in 30% (n=31), suggesting a lower baseline risk compared with the nomogram development cohort. Receiver operating characteristic curve analysis showed areas under curve (AUCs) from 0.77 to 0.80 for nomogram validation. An updated model was constructed with improved calibration and similar discrimination (AUC 0.79).

CONCLUSIONS

Age, prostate volume, PI-RADS, and PSA predict benign pathology on MRI/US fusion-targeted biopsy in men with a prior negative 12-core systematic biopsy. The validated and updated nomogram demonstrated high diagnostic accuracy and may further aid in the decision to avoid a biopsy in men with a prior negative biopsy.

PATIENT SUMMARY

We externally validated a clinically useful tool that predicts benign prostate pathology on magnetic resonance imaging/ultrasound fusion-targeted biopsy in men with a prior negative 12-core systematic biopsy and updated this predictive tool to improve its performance in patient counseling regarding the need for a repeat biopsy.

Contouring of prostate tumors on multiparametric MRI: Evaluation of clinical delineations in a multicenter radiotherapy trial

PURPOSE

To date no guidelines are available for contouring prostate cancer inside the gland, as visible on multiparametric (mp-) MRI. We assessed inter-institutional differences in interpretation of mp-MRI in the multicenter phase III FLAME trial.

METHODS

We analyzed clinical delineations on mp-MRI and clinical characteristics from 260 patients across three institutes. We performed a logistic regression analysis to examine each institute's weighting of T2w, ADC and K^trans intensity maps in the delineation of the cancer. As reviewing of all delineations by an expert panel is not feasible, we made a selection based on discrepancies between a published tumor probability (TP) model and each institute's clinical delineations using Areas Under the ROC Curve (AUC) analysis.

RESULTS

Regression coefficients for the three institutes were -0.07, -0.27 and -0.11 for T2w, -1.96, -0.53 and -0.65 for ADC and 0.15, 0.20 and 0.62 for K^trans, with significant differences between institutes for ADC and K^trans. AUC analysis showed median AUC values of 0.92, 0.80 and 0.79. Five patients with lowest AUC values were reviewed by a uroradiologist.

CONCLUSION

Regression coefficients revealed considerably different interpretations of mp-MRI in tumor contouring between institutes and demonstrated the need for contouring guidelines. Based on AUC values outlying delineations could efficiently be identified for review.

Diagnostic Utility of a Likert Scale Versus Qualitative Descriptors and Length of Capsular Contact for Determining Extraprostatic Tumor Extension at Multiparametric Prostate MRI

OBJECTIVE

The purpose of this study is to determine the reproducibility and diagnostic performance of a Likert scale in comparison with the European Society of Urogenital Radiology (ESUR) criteria and tumor-pseudocapsule contact length (TCL) for the detection of extraprostatic extension (EPE) at multiparametric MRI.

MATERIALS AND METHODS

This was a retrospective review of all men who underwent multiparametric MRI followed by prostatectomy between November 2015 and July 2016. Multiparametric 3-T MRI studies with an endorectal coil were independently reviewed by five readers who assigned the likelihood of EPE using a 1-5 Likert score, ESUR criteria, and TCL (> 10 mm). EPE outcome (absent or present) for the index lesion at whole-mount histopathologic analysis was the standard of reference. Odds ratios (ORs) and areas under the ROC curve (A_z) were used for diagnostic accuracy. The interreader agreement was determined using a weighted kappa coefficient. A p < 0.05 was considered significant.

RESULTS

Eighty men met the eligibility criteria. At univariate analysis, the Likert score showed the strongest association (OR, 1.8) with EPE, followed by prostate-specific antigen level (OR, 1.7), ESUR score (OR, 1.6), and index lesion size (OR, 1.2). At multivariable analysis, higher Likert score (OR, 1.8) and prostate-specific antigen level (OR, 1.6-1.7) were independent predictors of EPE. The A_z value for Likert scores was statistically significantly higher (0.79) than that for TCL (0.74; p < 0.01), but not statistically significantly higher than the value for ESUR scores (0.77; p = 0.17). Interreader agreement with Likert (κ = 0.52) and ESUR scores (κ = 0.55) was moderate and slightly superior to that for TCL (κ = 0.43). Except for TCL among inexperienced readers (κ = 0.34), reader experience did not affect interreader agreement.

CONCLUSION

A Likert score conveying the degree of suspicion at multiparametric MRI is a stronger predictor of EPE than is either ESUR score or TCL and may facilitate informed decision making, patient counseling, and treatment planning.

[Indications and limits of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about indications and limits of ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 107 articles were analysed.

RESULTS

The objective to combine reduction of side effects and oncological control has induced recent development of several ablative therapies. Beyond this heterogeneity, some preferential indications appear: unilateral cancer of low risk (but with significant volume, excluding active surveillance) or intermediate risk (excluding majority of grade 4); treatment targeted the index lesion, by quarter or hemi-ablation, based on biopsy and mpMRI. In addition, indications must considered specific limits of each energy, such as gland volume and tumor localization.

CONCLUSION

Based on new imaging and biopsy, ablative therapies will probably increased its role in the future in management of localize prostate cancer. The multiple ongoing trials will certainly be helpful to better define their indications and limits.

Magnetic resonance imaging targeted transperineal prostate biopsy: a local anaesthetic approach

BACKGROUND

Despite high rates of disease misclassification and sepsis, the use of transrectal biopsy remains commonplace. Transperineal mapping biopsies mitigate these problems but carry increased cost and patient burden. Local anaesthetic, multiparametric magnetic resonance imaging (MRI)-targeted transperineal biopsy may offer an alternative. Here, we aim to determine the feasibility, tolerability and detection rates of clinically significant prostate cancer using a local anaesthetic, transperineal, MRI-targeted biopsy technique.

METHODS

Tertiary referral centre in which 181 consecutive men underwent local anaesthetic, transperineal MRI-targeted prostate biopsy (September 2014 to January 2016). A standardized local anaesthetic technique was used to obtain targeted biopsies using visual estimation with the number of targeted cores determined by each of a number of users. We assessed adverse events, patient visual analogue pain scores and detection rates of clinically significant cancer (defined by University College London (UCL) definitions one and two and separately by the presence of dominant and non-dominant Gleason pattern 4). We secondarily assessed detection of any cancer, rates of detection by MRI (Likert) score and by presenting PSA. Differences were assessed using Chi-squared tests (P<0.05).

RESULTS

One hundred eighty-one men with 243 lesions were included. There were no episodes of sepsis or re-admissions and one procedure was abandoned owing to patient discomfort. Twenty-three out of 25 (92%) men would recommend the procedure to another. Median visual analogue pain score was 1.0 (interquartile range: 0.0-2.4). A total 104/181 (57%) had UCL definition 1 disease (Gleason ⩾4+3 and/or maximum cancer length ⩾6 mm) and 129/181 (71%) had UCL definition 2 cancer (Gleason ⩾3+4 and/or maximum cancer length ⩾4 mm). Fifty-four out of 181 (30%) and 124/181 (69%) had dominant and non-dominant pattern 4 disease or greater (irrespective of cancer length). Any cancer was detected in 142/181 (78%). Significant disease was more likely in higher MRI-scoring lesions and in men with PSAs ⩾10 ng ml-1.

CONCLUSIONS

This approach to prostate biopsy is feasible, tolerable and can be performed in ambulatory settings.

Diagnostic accuracy of a five-point Likert scoring system for magnetic resonance imaging (MRI) evaluated according to results of MRI/ultrasonography image-fusion targeted biopsy of the prostate

OBJECTIVE

To evaluate the accuracy of a magnetic resonance imaging (MRI)-based Likert scoring system in the detection of clinically significant prostate cancer (CSPC), using MRI/ultrasonography (US) image-fusion targeted biopsy (FTB) as a reference standard.

PATIENTS AND METHODS

We retrospectively reviewed 1218 MRI-detected lesions in 629 patients who underwent subsequent MRI/US FTB between October 2012 and August 2015. 3-Tesla MRI was independently reported by one of eight radiologists with varying levels of experience and scored on a five-point Likert scale. All lesions with Likert scores 1-5 were prospectively defined as targets for MRI/US FTB. CSPC was defined as Gleason score ≥7.

RESULTS

The median patient age was 64 years, PSA level 6.97 ng/mL and estimated prostate volume 52.2 mL. Of 1218 lesions, 48% (n = 581) were rated as Likert 1-2, 35% (n = 428) were Likert 3 and 17% (n = 209) were Likert 4-5. For Likert scores 1-5, the overall cancer detection rates were 12%, 13%, 22%, 50% and 59%, respectively, and the CSPC detection rates were 4%, 4%, 12%, 33% and 48%, respectively. Grading using the five-point scale showed strong positive correlation with overall cancer detection rate (r = 0.949, P = 0.05) and CSPC detection rate (r = 0.944, P = 0.05). By comparison, in Likert 4-5 lesions, significant differences were noted in overall cancer detection rate (63% vs 35%; P = 0.001) and CSPC detection rate (47% vs 29%; P = 0.027) for the more experienced vs the less experienced radiologists.

CONCLUSIONS

The detection rates of overall cancer and CSPC strongly correlated with the five-point grading of the Likert scale. Among radiologists with different levels of experience, there were significant differences in these cancer detection rates.

68Ga-PSMA-11 PET/CT for prostate cancer staging and risk stratification in Chinese patients

We evaluated the clinical utility of ⁶⁸Ga-PSMA-11 PET/CT for staging and risk stratification of treatment-naïve prostate cancer (PCa) and metastatic castrate-resistant prostate cancer (mCRPC). Twenty-two consecutive patients with treatment-naïve PCa and 18 with mCRPC were enrolled. ⁶⁸Ga-PSMA-11 PET/CT and magnetic resonance imaging (MRI) were performed for the evaluation of primary prostatic lesions, and bone scans were used for evaluation bone metastasis. Among the 40 patients, 37 (92.5% [22 treatment-naïve PCa, 15 mCRPC]) showed PSMA-avid lesions on ⁶⁸Ga-PSMA-11 images. Only 3 patients with stable mCRPC after chemotherapy were negative for PSMA. The sensitivity, specificity and accuracy of ⁶⁸Ga-PSMA-11 imaging were 97.3%, 100.0% and 97.5%, respectively. The maximum standardized uptake (SUV_max) of prostatic lesions was 17.09 ± 11.08 and 13.33 ± 12.31 in treatment-naïve PCa and mCRPC, respectively. ⁶⁸Ga-PSMA-11 revealed 105 metastatic lymph nodes in 15 patients; the SUV_max was 16.85 ± 9.70 and 7.54 ± 5.20 in treatment-naïve PCa and mCRPC, respectively. ⁶⁸Ga-PSMA-11 PET/CT also newly detected visceral metastasis in 9 patients (22.5%) and bone metastasis in 29 patients (72.5%). ⁶⁸Ga-PSMA-11 PET/CT exhibits potential for staging and risk stratification in naïve PCa, as well as improved sensitivity for detection of lymph node and remote metastasis.

Results of Targeted Biopsy in Men with Magnetic Resonance Imaging Lesions Classified Equivocal, Likely or Highly Likely to Be Clinically Significant Prostate Cancer

BACKGROUND

The Prostate Imaging Reporting and Data System (PI-RADS) is the most commonly used scoring system in prostate magnetic resonance imaging (MRI). One of the available techniques to target suspicious lesions is direct in-bore MRI-guided biopsy (MRGB).

OBJECTIVE

To report on the experience and results of MRGB in a large cohort of patients with lesions classified as equivocal (PI-RADS 3), likely (PI-RADS 4), or highly likely (PI-RADS 5) to be clinically significant (cs) prostate cancer (PCa).

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively included 1057 patients having MRGB, between January 2012 and September 2016, of lesions classified as PI-RADS≥3 on multiparametric MRI. Biopsy-naïve patients, patients with prior negative systematic transrectal ultrasound-guided biopsy, and patients in active surveillance were included.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome measurement is the detection rate of csPCa. Descriptive statistics and chi-square tests were used to calculate the differences in proportions. We considered a Gleason score of ≥3+4 as csPCa.

RESULTS AND LIMITATIONS

PCa was diagnosed in 35% (55/156), 60% (223/373), and 91% (479/528), and csPCa in 17% (26/156), 34% (128/373), and 67% (352/528) of patients with PI-RADS 3, 4, and 5 lesions, respectively. Follow-up of patients with negative biopsy findings resulted in csPCa in 1.7% (5/300) after a median period of 41 (interquartile range 25-50) mo. The evaluation of prostate-specific antigen density (PSAD) to predict csPCa resulted in 42% of patients with a PI-RADS 3 lesion who could avoid biopsy in case a PSAD of ≥ 0.15ng/ml/ml would be used. In 6% (95% confidence interval, 2-15), csPCa would then be missed. The study is limited because of its retrospective character.

CONCLUSIONS

MRGB in lesions scored PI-RADS≥3 yields high detection rates of csPCa in daily clinical practice in cases with previous negative biopsy.

PATIENT SUMMARY

In daily clinical practice, direct in-bore magnetic resonance imaging-guided biopsy of suspicious lesions reported according to the Prostate Imaging Reporting and Data System yields high detection rates of clinically significant prostate cancer.

Detection of prostate cancer using magnetic resonance imaging/ultrasonography image-fusion targeted biopsy in African-American men

OBJECTIVE

To assess the diagnostic yield of targeted prostate biopsy in African-American (A-A) men using image fusion of multi-parametric magnetic resonance imaging (mpMRI) with real-time transrectal ultrasonography (US).

PATIENTS AND METHODS

We retrospectively analysed 661 patients (117 A-A and 544 Caucasian) who had mpMRI before biopsy and then underwent MRI/US image-fusion targeted biopsy (FTB) between October 2012 and August 2015. The mpMRIs were reported on a 5-point Likert scale of suspicion. Clinically significant prostate cancer (CSPC) was defined as biopsy Gleason score ≥7.

RESULTS

After controlling for age, prostate-specific antigen level and prostate volume, there were no significant differences between A-A and Caucasian men in the detection rate of overall cancer (35.0% vs 34.2%, P = 0.9) and CSPC (18.8% vs 21.7%, P = 0.3) with MRI/US FTB. There were no significant differences between the races in the location of dominant lesions on mpMRI, and in the proportion of 5-point Likert scoring. In A-A men, MRI/US FTB from the grade 4-5 lesions outperformed random biopsy in the detection rate of overall cancer (70.6% vs 37.2%, P = 0.003) and CSPC (52.9% vs 12.4%, P < 0.001). MRI/US FTB outperformed random biopsy in cancer core length (5.0 vs 2.4 mm, P = 0.001), in cancer rate per core (24.9% vs 6.8%, P < 0.001), and in efficiency for detecting one patient with CSPC (mean number of cores needed 13.3 vs 81.9, P < 0.001), respectively.

CONCLUSIONS

Our key finding confirms a lack of racial difference in the detection rate of overall prostate cancers and CSPC with MRI/US FTB between A-A and Caucasian men. MRI/US FTB detected more CSPC using fewer cores compared with random biopsy.

Are Dynamic Contrast-Enhanced Images Necessary for Prostate Cancer Detection on Multiparametric Magnetic Resonance Imaging?

BACKGROUND

To compare the results of magnetic resonance imaging (MRI) with and without contrast-enhanced sequences for the detection of clinically significant prostate cancer. The value of contrast in the MRI protocol for the detection of prostate tumors has been discussed in previous studies.

MATERIALS AND METHODS

We performed an institutional review board-approved, retrospective study of patients who had undergone prostate MRI followed by fusion biopsy during a 16-month period. The patients had undergone MRI on a 3-Tesla scanner with a phased-array coil using a routine multiparametric protocol: T2-weighted, diffusion, and dynamic postcontrast enhancement sequences. The examination films were read independently by 2 readers in 2 sessions: first without contrast-enhanced images and second with contrast-enhanced images. The images were graded according to the suspicion of clinically significant prostate cancer (scale, 1-5). The kappa coefficient was used to compare the readings with and without contrast. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for both readers were calculated using the biopsy findings as a reference standard. The level for statistical significance was set at P < .05.

RESULTS

A total of 118 patients were included, and clinically significant prostate cancer was found in 48 patients (40.7%). The MRI findings on both contrast-enhanced and noncontrast-enhanced images had no statistically significant differences for either reader (P > .05 for all levels of suspicion). The sensitivity ranged from 68.3% to 80.7%, specificity from 57.1% to 77.1%, positive predictive value from 29.9% to 38.8%, negative predictive value from 88.0% to 91.3%, and accuracy from 60.6% to 73.0%.

CONCLUSION

Our results show that contrast-enhanced sequences provide minimal or no increased value for the detection of clinically significant prostate cancer.