Publications by authors named "Ivan Jambor"

56 Publications

Computer extracted gland features from H&E predicts prostate cancer recurrence comparably to a genomic companion diagnostic test: a large multi-site study.

NPJ Precis Oncol 2021 May 3;5(1):35. Epub 2021 May 3.

Department of Urology, Case Western Reserve University, Cleveland, OH, USA.

Existing tools for post-radical prostatectomy (RP) prostate cancer biochemical recurrence (BCR) prognosis rely on human pathologist-derived parameters such as tumor grade, with the resulting inter-reviewer variability. Genomic companion diagnostic tests such as Decipher tend to be tissue destructive, expensive, and not routinely available in most centers. We present a tissue non-destructive method for automated BCR prognosis, termed "Histotyping", that employs computational image analysis of morphologic patterns of prostate tissue from a single, routinely acquired hematoxylin and eosin slide. Patients from two institutions (n = 214) were used to train Histotyping for identifying high-risk patients based on six features of glandular morphology extracted from RP specimens. Histotyping was validated for post-RP BCR prognosis on a separate set of n = 675 patients from five institutions and compared against Decipher on n = 167 patients. Histotyping was prognostic of BCR in the validation set (p < 0.001, univariable hazard ratio [HR] = 2.83, 95% confidence interval [CI]: 2.03-3.93, concordance index [c-index] = 0.68, median years-to-BCR: 1.7). Histotyping was also prognostic in clinically stratified subsets, such as patients with Gleason grade group 3 (HR = 4.09) and negative surgical margins (HR = 3.26). Histotyping was prognostic independent of grade group, margin status, pathological stage, and preoperative prostate-specific antigen (PSA) (multivariable p < 0.001, HR = 2.09, 95% CI: 1.40-3.10, n = 648). The combination of Histotyping, grade group, and preoperative PSA outperformed Decipher (c-index = 0.75 vs. 0.70, n = 167). These results suggest that a prognostic classifier for prostate cancer based on digital images could serve as an alternative or complement to molecular-based companion diagnostic tests.
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http://dx.doi.org/10.1038/s41698-021-00174-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093226PMC
May 2021

Prospective comparison of F-PSMA-1007 PET/CT, whole-body MRI and CT in primary nodal staging of unfavourable intermediate- and high-risk prostate cancer.

Eur J Nucl Med Mol Imaging 2021 Mar 13. Epub 2021 Mar 13.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Purpose: To prospectively compare F-prostate-specific membrane antigen (PSMA)-1007 positron emission tomography (PET)/CT, whole-body magnetic resonance imaging (WBMRI) including diffusion-weighted imaging (DWI) and standard computed tomography (CT), in primary nodal staging of prostate cancer (PCa).

Methods: Men with newly diagnosed unfavourable intermediate- or high-risk PCa prospectively underwent F-PSMA-1007 PET/CT, WBMRI with DWI and contrast-enhanced CT within a median of 8 days. Six readers (two for each modality) independently reported pelvic lymph nodes as malignant, equivocal or benign while blinded to the other imaging modalities. Sensitivity, specificity and accuracy were reported according to optimistic (equivocal lesions interpreted as benign) and pessimistic (equivocal lesions interpreted as malignant) analyses. The reference standard diagnosis was based on multidisciplinary consensus meetings where available histopathology, clinical and follow-up data were used.

Results: Seventy-nine patients completed all the imaging modalities, except for one case of interrupted WBMRI. Thirty-one (39%) patients had pelvic lymph node metastases, which were detected in 27/31 (87%), 14/31 (45%) and 8/31 (26%) patients by F-PSMA-1007 PET/CT, WBMRI with DWI and CT, respectively (optimistic analysis). In 8/31 (26%) patients, only F-PSMA-1007 PET/CT detected malignant lymph nodes, while the other two imaging modalities were reported as negative. At the patient level, sensitivity and specificity values for F-PSMA-1007 PET/CT, WBMRI with DWI and CT in optimistic analysis were 0.87 (95%CI 0.71-0.95) and 0.98 (95%CI 0.89-1.00), 0.37 (95%CI 0.22-0.55) and 0.98 (95%CI 0.89-1.00) and 0.26 (95%CI 0.14-0.43) and 1.00 (95%CI 0.93-1.00), respectively.

Conclusion: F-PSMA-1007 PET/CT showed significantly greater sensitivity in nodal staging of primary PCa than did WBMRI with DWI or CT, while maintaining high specificity.

Clinical Trial Registration: Clinicaltrials.gov ID: NCT03537391.
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http://dx.doi.org/10.1007/s00259-021-05296-1DOI Listing
March 2021

Whole Brain Adiabatic T and Relaxation Along a Fictitious Field Imaging in Healthy Volunteers and Patients With Multiple Sclerosis: Initial Findings.

J Magn Reson Imaging 2021 Mar 6. Epub 2021 Mar 6.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Background: In preclinical models of multiple sclerosis (MS), both adiabatic T (T ) and relaxation along a fictitious field (RAFF) imaging have demonstrated potential to noninvasively characterize MS.

Purpose: To evaluate the feasibility of whole brain T and RAFF imaging in healthy volunteers and patients with MS.

Study Type: Single institutional clinical trial.

Subjects: 38 healthy volunteers (24-69 years) and 21 patients (26-59 years) with MS. Five healthy volunteers underwent a second MR examination performed within 8 days. Clinical disease severity (The Expanded Disability Status Scale [EDSS] and The Multiple Sclerosis Severity Score [MSSS]) was evaluated at baseline and 1-year follow-up (FU).

Field Strength/sequence: RAFF in second rotating frame of reference (RAFF2) was performed at 3 T using 3D-fast-field echo with magnetization preparation, RF amplitude of 11.74 μT while the corresponding value for T was 13.50 μT. T -, T -, and FLAIR-weighted images were acquired with reconstruction voxel size 1.0 × 1.0 × 1.0 mm .

Assessment: The parametric maps of T and RAFF2 (T ) were calculated using a monoexponential model. Semi-automatic segmentation of MS lesions, white matter (WM), and gray matter (GM), and WM tracks was performed using T -, T -, and FLAIR-weighted images.

Statistical Tests: Regression analysis was used to evaluate correlation of T and T with age and disease severity while a Friedman test followed by Wilcoxon Signed Rank test for differences between tissue types. Short-term repeatability was evaluated on voxel level.

Results: Both T and T demonstrated good short-term repeatability with relative differences on voxel level in the range of 6.1%-11.9%. Differences in T and T between the tissue types in MS patients were significant (P < 0.05). T and T correlated (P < 0.001) with baseline EDSS/MSSM and disease progression at FU (P < 0.001).

Data Conclusion: Whole brain T and T at 3 T was feasible with significant differences in T and T values between tissues types and correlation with disease severity.

Evidence Level: 1 TECHNICAL EFFICACY: Stage 1.
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http://dx.doi.org/10.1002/jmri.27586DOI Listing
March 2021

Docetaxel chemotherapy response in PC3 prostate cancer mouse model detected by rotating frame relaxations and water diffusion.

NMR Biomed 2021 Apr 4;34(4):e4483. Epub 2021 Feb 4.

A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.

MRI is a common method of prostate cancer diagnosis. Several MRI-derived markers, including the apparent diffusion coefficient (ADC) based on diffusion-weighted imaging, have been shown to provide values for prostate cancer detection and characterization. The hypothesis of the study was that docetaxel chemotherapy response could be picked up earlier with rotating frame relaxation times T and T than with the continuous wave T , adiabatic T , adiabatic T , T , T or water ADC. Human PC3 prostate cancer cells expressing a red fluorescent protein were implanted in 21 male mice. Docetaxel chemotherapy was given once a week starting 1 week after cell implantation for 10 randomly selected mice, while the rest served as a control group (n = 11). The MRI consisted of relaxation along a fictitious field (RAFF) in the second (RAFF2) and fourth (RAFF4) rotating frames, T and T , continuous wave T , adiabatic T and adiabatic T relaxation time measurements and water ADC. MRI was conducted at 7 T, once a week up to 4 weeks from cell implantation. The tumor volume was monitored using T -weighted MRI and optical imaging. The histology was evaluated after the last imaging time point. Significantly reduced RAFFn, T T and conventional relaxation times 4 weeks after tumor implantation were observed in the treated tumors compared with the controls. The clearest short- and long-term responses were obtained with T , while no clear improvement in response to treatment was detected with novel methods compared with conventional methods or with RAFFn compared with all others. The tumor volume decreased after a two-week time point for the treated group and increased significantly in the control group, which was supported by increasing red fluorescent light emission in the control tumors. Decreased relaxation times were associated with successful chemotherapy outcomes. The results indicate altered relaxation mechanisms compared with higher dose chemotherapies previously published.
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http://dx.doi.org/10.1002/nbm.4483DOI Listing
April 2021

Using biomarkers in patients with positive multiparametric magnetic resonance imaging: 4Kscore predicts the presence of cancer outside the index lesion.

Int J Urol 2021 Jan 27;28(1):47-52. Epub 2020 Sep 27.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Objectives: To evaluate if the blood biomarker, 4Kscore, in addition to multiparametric magnetic resonance imaging information could identify patients who would benefit from undergoing only a targeted biopsy.

Methods: We retrospectively analyzed a population of 256 men with positive multiparametric magnetic resonance imaging who underwent standard + targeted biopsy at Mount Sinai Hospital, New York, NY, USA. 4Kscore (OPKO Health, Miami, FL, USA) was sampled from all patients before biopsy. Uni- and multivariable binary logistic regression analyses were carried out to predict clinically significant prostate cancer, defined as International Society of Urological Pathology grade group ≥2, in standard biopsy cores. The model with the best area under the curve was selected and internal validation was carried out using the leave-one-out cross-validation.

Results: The developed model showed an area under the curve of 0.86. Carrying out only targeted biopsy in patients with a model-derived probability <12.5% resulted in 39.5% (n = 101) fewer standard biopsies and a 33.9% (n = 20) reduction of detecting grade group 1 disease, while missing grade group ≥2 in 5.2% (n = 4) using standard biopsy only and 1.1% (n = 1) using standard biopsy + targeted biopsy.

Conclusions: 4Kscore in combination with multiparametric magnetic resonance imaging can help to reduce unnecessary standard biopsy and decrease detection of clinically insignificant prostate cancer.
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http://dx.doi.org/10.1111/iju.14385DOI Listing
January 2021

Combined Use of Prostate-specific Antigen Density and Magnetic Resonance Imaging for Prostate Biopsy Decision Planning: A Retrospective Multi-institutional Study Using the Prostate Magnetic Resonance Imaging Outcome Database (PROMOD).

Eur Urol Oncol 2020 Sep 21. Epub 2020 Sep 21.

Department of Urology and Organ Transplantation, University of Foggia, Foggia, Italy.

Background: Previous studies suggested that prostate-specific antigen (PSA) density (PSAd) combined with magnetic resonance imaging (MRI) may help avoid unnecessary prostate biopsy (PB) with a limited risk of missing clinically significant prostate cancer (csPCa; Gleason grade group [GGG] >1).

Objective: To define optimal diagnostic strategies based on the combined use of PSAd and MRI in patients at risk of prostate cancer (PCa).

Design, Setting, And Participants: A retrospective analysis of the international multicenter Prostate MRI Outcome Database (PROMOD), including 2512 men having undergone PSAd and prostate MRI before PB between 2013 and 2019, was performed.

Outcome Measurements And Statistical Analysis: Rates of avoided PB, missed GGG 1, and csPCa according to 10 strategies based on PSAd values and MRI reporting scores (Prostate Imaging Reporting and Data System [PI-RADS]/Likert/IMPROD biparametric prostate MRI Likert). Decision curve analysis (DCA) was used to statistically compare the net benefit of each strategy. Combined systematic and targeted biopsies were used for reference.

Results And Limitations: According to DCA, the best strategy in biopsy-naive patients was #7 (PI-RADS/Likert 4-5 or PI-RADS/Likert 3 if PSAd >0.2), which avoided 41.2% PBs while missed 44% of GGG 1 and 10.9% of csPCa cases. From a clinical standpoint, however, strategies with a lower risk of missing csPCa included #10 (PI-RADS/Likert 4-5 or PI-RADS 3 if PSAd >0.10 or PSAd >0.2), which avoided 27% PBs while missing 24.4% GGG 1 and 4% csPCa cases, or #5 (PI-RADS/Likert 3-5 or PSAd>0.15), which avoided 14.7% PBs while missing 9.3% GGG 1 and 1.7% csPCa cases. Similar results were found in patients with a previous negative biopsy. This study is limited by its retrospective nature, and no central review of MRI and histopathological findings.

Conclusions: Combined PSAd and MRI findings allows individualization of the decision to perform PB on the basis of the risk of missing PCa that both patients and clinicians are ready to accept to avoid this procedure.

Patient Summary: We compared several biopsy strategies based on a combination of prostate magnetic resonance imaging findings and prostate-specific antigen density, providing a readily available tool for each center and practicing urologist to counsel patients about their individual risk of significant prostate cancer.
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http://dx.doi.org/10.1016/j.euo.2020.08.014DOI Listing
September 2020

Expanding Active Surveillance Inclusion Criteria: A Novel Nomogram Including Preoperative Clinical Parameters and Magnetic Resonance Imaging Findings.

Eur Urol Oncol 2020 Sep 2. Epub 2020 Sep 2.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Background: Current European Association of Urology, American Urological Association, and National Comprehensive Cancer Network guidelines recommend active surveillance (AS) for selected intermediate-risk prostate cancer (PCa) patients. However, limited evidence exists regarding which men can be selected safely.

Objective: To externally validate the Gandaglia risk calculator (Gandaglia-RC), designed to predict adverse pathology (AP) at radical prostatectomy (RP) and thus able to improve selection of intermediate-risk PCa patients suitable for AS, and to assess whether addition of magnetic resonance imaging (MRI) findings (MAP model) improves the predictive ability of Gandaglia-RC.

Design, Setting, And Participants: This is a retrospective analysis of a single-center cohort of 1284 consecutive men with low- and intermediate-risk PCa treated with RP between 2013 and 2019.

Outcome Measurements And Statistical Analysis: AP was defined as non-organ-confined disease and/or lymph node invasion and/or pathological grade group≥3 at RP. Logistic regression was used to calculate the predictors of AP; calculated coefficients were used to develop a risk score. Receiver operating characteristic curve analysis and decision curve analysis were performed to evaluate the net benefit within models.

Results And Limitations: At multivariable analysis, age at surgery, prostate-specific antigen, systematic and targeted biopsy Gleason grade group, MRI prostate volume, Prostate Imaging Reporting and Data System score, and MRI extraprostatic extension were significantly associated with AP. The model significantly improved the ability of Gandaglia-RC to predict AP (area under the curve 0.71 vs 0.63 [p<0.0001]). Using a 30% threshold, the proportions of men eligible for AS were 45% and 77% and the risks of AP were 16% and 17%, for Gandaglia-RC and MAP model, respectively.

Conclusions: Compared with Gandaglia-RC, the MAP model significantly increased the number of patients eligible for AS without significantly increasing the risk of AP at RP.

Patient Summary: In this report, we have developed a risk prediction tool to select men for conservative treatment of prostate cancer. Using the novel tool, more men could safely be allocated to conservative treatment rather than surgery or radiation.
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http://dx.doi.org/10.1016/j.euo.2020.08.001DOI Listing
September 2020

Added value of systematic biopsy in men with a clinical suspicion of prostate cancer undergoing biparametric MRI-targeted biopsy: multi-institutional external validation study.

World J Urol 2020 Aug 10. Epub 2020 Aug 10.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Purpose: We aimed to develop and externally validate a nomogram based on MRI volumetric parameters and clinical information for deciding when SBx should be performed in addition to TBx in man with suspicious prostate MRI.

Materials And Methods: Retrospective analyses of single (IMPROD, NCT01864135) and multi-institution (MULTI-IMPROD, NCT02241122) clinical trials. All men underwent a unique rapid biparametric magnetic resonance imaging (IMPROD bpMRI) consisting of T2-weighted imaging and three separate DWI acquisitions. Men with IMPROD bpMRI Likert scores of 3-5 were included. Logistic regression models were developed using IMPROD trial (n = 122) and validated using MULTI-IMPROD trial (n = 262) data. The model's performance was evaluated in the terms of PCa detection with Gleason Grade Group 1 (clinically insignificant prostate cancer, iPCa) and > 1 (clinically significant prostate cancer, csPCa). Net benefits and decision curve analyses (DCA) were compared. Combined biopsies were used for reference.

Results: The developed nomogram included age, PSA, prostate volume, MRI suspicion score (IMPROD bpMRI Likert or PIRADsv2.1 score), MRI-suspicion lesion volume percentage, and lesion location. All these variables were significant predictors of csPCa in SBx in multivariable analysis. In the validation cohort (n = 262) using different nomogram cutoffs, 19-43% of men would have avoided SBx while missing 1-4% of csPCa and avoiding detection of 9-20% of iPCa. Similar performance was found for nomograms using IMPROD bpMRI Likert score or v2.1.

Conclusions: The developed nomogram demonstrated potential to select men with a clinical suspicion of PCa who would benefit from performing SBx in addition to TBx. Public access to the nomogram is provided at: https://petiv.utu.fi/multiimprod/ .
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http://dx.doi.org/10.1007/s00345-020-03393-8DOI Listing
August 2020

Test-retest repeatability of a deep learning architecture in detecting and segmenting clinically significant prostate cancer on apparent diffusion coefficient (ADC) maps.

Eur Radiol 2021 Jan 23;31(1):379-391. Epub 2020 Jul 23.

Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Objectives: To evaluate short-term test-retest repeatability of a deep learning architecture (U-Net) in slice- and lesion-level detection and segmentation of clinically significant prostate cancer (csPCa: Gleason grade group > 1) using diffusion-weighted imaging fitted with monoexponential function, ADC.

Methods: One hundred twelve patients with prostate cancer (PCa) underwent 2 prostate MRI examinations on the same day. PCa areas were annotated using whole mount prostatectomy sections. Two U-Net-based convolutional neural networks were trained on three different ADC b value settings for (a) slice- and (b) lesion-level detection and (c) segmentation of csPCa. Short-term test-retest repeatability was estimated using intra-class correlation coefficient (ICC(3,1)), proportionate agreement, and dice similarity coefficient (DSC). A 3-fold cross-validation was performed on training set (N = 78 patients) and evaluated for performance and repeatability on testing data (N = 34 patients).

Results: For the three ADC b value settings, repeatability of mean ADC of csPCa lesions was ICC(3,1) = 0.86-0.98. Two CNNs with U-Net-based architecture demonstrated ICC(3,1) in the range of 0.80-0.83, agreement of 66-72%, and DSC of 0.68-0.72 for slice- and lesion-level detection and segmentation of csPCa. Bland-Altman plots suggest that there is no systematic bias in agreement between inter-scan ground truth segmentation repeatability and segmentation repeatability of the networks.

Conclusions: For the three ADC b value settings, two CNNs with U-Net-based architecture were repeatable for the problem of detection of csPCa at the slice-level. The network repeatability in segmenting csPCa lesions is affected by inter-scan variability and ground truth segmentation repeatability and may thus improve with better inter-scan reproducibility.

Key Points: • For the three ADC b value settings, two CNNs with U-Net-based architecture were repeatable for the problem of detection of csPCa at the slice-level. • The network repeatability in segmenting csPCa lesions is affected by inter-scan variability and ground truth segmentation repeatability and may thus improve with better inter-scan reproducibility.
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http://dx.doi.org/10.1007/s00330-020-07065-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821380PMC
January 2021

A Prospective Comparison of F-prostate-specific Membrane Antigen-1007 Positron Emission Tomography Computed Tomography, Whole-body 1.5 T Magnetic Resonance Imaging with Diffusion-weighted Imaging, and Single-photon Emission Computed Tomography/Computed Tomography with Traditional Imaging in Primary Distant Metastasis Staging of Prostate Cancer (PROSTAGE).

Eur Urol Oncol 2020 Jul 13. Epub 2020 Jul 13.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Background: Computed tomography (CT) and bone scintigraphy (BS) are the imaging modalities currently used for distant metastasis staging of prostate cancer (PCa).

Objective: To compare standard staging modalities with newer and potentially more accurate imaging modalities.

Design, Setting, And Participants: This prospective, single-centre trial (NCT03537391) enrolled 80 patients with newly diagnosed high-risk PCa (International Society of Urological Pathology grade group ≥3 and/or prostate-specific antigen [PSA] ≥20 and/or cT ≥ T3; March 2018-June 2019) to undergo primary metastasis staging with two standard and three advanced imaging modalities.

Outcome Measurements And Statistical Analysis: The participants underwent the following five imaging examinations within 2 wk of enrolment and without a prespecified sequence: BS, CT, Tc-hydroxymethylene diphosphonate (Tc-HMDP) single-photon emission computed tomography (SPECT)-CT, 1.5 T whole-body magnetic resonance imaging (WBMRI) using diffusion-weighted imaging, and F-prostate-specific membrane antigen-1007 (F-PSMA-1007) positron emission tomography(PET)-CT. Each modality was reviewed by two independent experts blinded to the results of the prior studies, who classified lesions as benign, equivocal, or malignant. Pessimistic and optimistic analyses were performed to resolve each equivocal diagnosis. The reference standard diagnosis was defined using all available information accrued during at least 12 mo of clinical follow-up. Patients with equivocal reference standard diagnoses underwent MRI and/or CT to search for the development of anatomical correspondence. PSMA PET-avid lesions without histopathological verification were rated to be malignant only if there was a corresponding anatomical finding suspicious for malignancy at the primary or follow-up imaging.

Results And Limitations: Seventy-nine men underwent all imaging modalities except for one case of interrupted MRI. The median interval per patient between the first and the last imaging study was 8 d (interquartile range [IQR]: 6-9). The mean age was 70 yr (standard deviation: 7) and median PSA 12 ng/mL (IQR:7-23). The median follow-up was 435 d (IQR: 378-557). Metastatic disease was detected in 20 (25%) patients. The imaging modality F-PSMA-1007 PET-CT had superior sensitivity and highest inter-reader agreement. The area under the receiver-operating characteristic curve (AUC) values for bone metastasis detection with PSMA PET-CT were 0.90 (95% confidence interval [CI]: 0.85-0.95) and 0.91 (95% CI: 0.87-0.96) for readers 1 and 2, respectively, while the AUC values for BS, CT, SPECT-CT, and WBMRI were 0.71 (95% CI: 0.58-0.84) and 0.8 (95% CI: 0.67-0.92), 0.53 (95% CI: 0.39-0.67) and 0.66 (95% CI: 0.54-0.77), 0.77 (95% CI: 0.65-0.89) and 0.75 (95% CI: 0.62-0.88), and 0.85 (95% CI: 0.74-0.96) and 0.67 (95% CI: 0.54-0.80), respectively, for the other four pairs of readers. The imaging method F-PSMA-1007 PET-CT detected metastatic disease in 11/20 patients in whom standard imaging was negative and influenced clinical decision making in 14/79 (18%) patients. In 12/79 cases, false positive bone disease was reported only by PSMA PET-CT. Limitations included a nonrandomised study setting and few histopathologically validated suspicious lesions.

Conclusions: Despite the risk of false positive bone lesions, F-PSMA-1007 PET-CT outperformed all other imaging methods studied for the detection of primary distant metastasis in high-risk PCa.

Patient Summary: In this report, we compared the diagnostic performance of conventional and advanced imaging. It was found that F-prostate-specific membrane antigen-1007 positron emission tomography/computed tomography (F-PSMA-1007 PET-CT) was superior to the other imaging modalities studied for the detection of distant metastasis at the time of initial diagnosis of high-risk prostate cancer. PSMA PET-CT also appears to detect some nonmetastatic bone lesions.
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http://dx.doi.org/10.1016/j.euo.2020.06.012DOI Listing
July 2020

Prediction of prostate cancer aggressiveness using F-Fluciclovine (FACBC) PET and multisequence multiparametric MRI.

Sci Rep 2020 06 10;10(1):9407. Epub 2020 Jun 10.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

The aim of this prospective single-institution clinical trial (NCT02002455) was to evaluate the potential of advanced post-processing methods for F-Fluciclovine PET and multisequence multiparametric MRI in the prediction of prostate cancer (PCa) aggressiveness, defined by Gleason Grade Group (GGG). 21 patients with PCa underwent PET/CT, PET/MRI and MRI before prostatectomy. DWI was post-processed using kurtosis (ADC, K), mono- (ADC), and biexponential functions (f, D, D) while Logan plots were used to calculate volume of distribution (V). In total, 16 unique PET (V, SUV) and MRI derived quantitative parameters were evaluated. Univariate and multivariate analysis were carried out to estimate the potential of the quantitative parameters and their combinations to predict GGG 1 vs >1, using logistic regression with a nested leave-pair out cross validation (LPOCV) scheme and recursive feature elimination technique applied for feature selection. The second order rotating frame imaging (RAFF), monoexponential and kurtosis derived parameters had LPOCV AUC in the range of 0.72 to 0.92 while the corresponding value for V was 0.85. he best performance for GGG prediction was achieved by K parameter of kurtosis function followed by quantitative parameters based on DWI, RAFF and F-FACBC PET. No major improvement was achieved using parameter combinations with or without feature selection. Addition of F-FACBC PET derived parameters (V, SUV) to DWI and RAFF derived parameters did not improve LPOCV AUC.
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http://dx.doi.org/10.1038/s41598-020-66255-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7287051PMC
June 2020

Negative Predictive Value of Biparametric Prostate Magnetic Resonance Imaging in Excluding Significant Prostate Cancer: A Pooled Data Analysis Based on Clinical Data from Four Prospective, Registered Studies.

Eur Urol Focus 2020 May 14. Epub 2020 May 14.

Department of Urology, University of Turku and Turku University hospital, Turku, Finland.

Background: Multiparametric prostate magnetic resonance imaging (mpMRI) can be considered the gold standard in prostate magnetic resonance imaging (MRI). Biparametric prostate MRI (bpMRI) is faster and could be a feasible alternative to mpMRI.

Objective: To determine the negative predictive value (NPV) of Improved Prostate Cancer Diagnosis (IMPROD) bpMRI as a whole and in clinical subgroups in primary diagnostics of clinically significant prostate cancer (CSPCa).

Design, Setting, And Participants: This is a pooled data analysis of four prospective, registered clinical trials investigating prebiopsy IMPROD bpMRI. Men with a clinical suspicion of prostate cancer (PCa) were included.

Intervention: Prebiopsy IMPROD bpMRI was performed, and an IMPROD bpMRI Likert scoring system was used. If suspicious lesions (IMPROD bpMRI Likert score 3-5) were visible, targeted biopsies in addition to systematic biopsies were taken.

Outcome Measurements And Statistical Analysis: Performance measures of IMPROD bpMRI in CSPCa diagnostics were evaluated. NPV was also evaluated in clinical subgroups. Gleason grade ≥3 + 4 in any biopsy core taken was defined as CSPCa.

Results And Limitations: A total of 639 men were included in the analysis. The mean age was 64 yr, mean prostate-specific antigen level was 8.9 ng/ml, and CSPCa prevalence was 48%. NPVs of IMPROD bpMRI Likert scores 3-5 and 4-5 for CSPCa were 0.932 and 0.909, respectively, and the corresponding positive predictive values were 0.589 and 0.720. Only nine of 132 (7%) men with IMPROD bpMRI Likert score 1-2 had CSPCa and none with Gleason score >7. Thus, 132 of 639 (21%) study patients could have avoided biopsies without missing a single Gleason >7 cancer in the study biopsies. In the subgroup analysis, no clear outlier was present. The limitation is uncertainty of the true CSPCa prevalence.

Conclusions: IMPROD bpMRI demonstrated a high NPV to rule out CSPCa. IMPROD bpMRI Likert score 1-2 excludes Gleason >7 PCa in the study biopsies.

Patient Summary: We investigated the feasibility of prostate magnetic resonance imaging (MRI) with the Improved Prostate Cancer Diagnosis (IMPROD) biparametric MRI (bpMRI) protocol in excluding significant prostate cancer. In this study, highly aggressive prostate cancer was excluded using the publicly available IMPROD bpMRI protocol (http://petiv.utu.fi/multiimprod/).
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http://dx.doi.org/10.1016/j.euf.2020.04.007DOI Listing
May 2020

Performance of prostate multiparametric MRI for prediction of prostate cancer extra-prostatic extension according to NCCN risk categories: implication for surgical planning.

Minerva Urol Nefrol 2020 Dec 16;72(6):746-754. Epub 2020 Mar 16.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Background: Prediction of extra-prostatic extension (EPE) in men undergoing radical prostatectomy (RP) is of utmost importance. Great variability in the performance of multiparametric magnetic resonance imaging (mpMRI) has been reported for prediction of EPE. The present study aimed to determine the diagnostic performance of mpMRI for predicting EPE in different National Comprehensive Cancer Network (NCCN) risk categories.

Methods: Overall 664 patients who underwent radical prostatectomy with a staging mpMRI were enrolled in this single-center, retrospective study. Patients with mpMRI report non-compliant with PI-RADSv2.0, were excluded. Patients were stratified according to NCCN criteria: very low/low (VLR-LR) to High Risk (HR) in order to assess final pathology EPE rates (focal and established). Sensitivity, specificity, positive and negative predictive values of staging mpMRI were computed in each group. Univariable and multivariable analysis were used to evaluate predictors of positive surgical margins.

Results: Pathological evaluation demonstrated established and focal EPE in 60 (9%) and 106 (16%) patients, respectively, while mpMRI suspicion for EPE was present in 180 (27%) patients. Age, preoperative PSA, PSA density, number of positive cores, NCCN groups, prostate volume, mpMRI suspicion for EPE, PIRADSv2.0 and lesion size differed significantly between the patients with any EPE and without EPE (all P≤0.05). The sensitivity of mpMRI in detecting any EPE varied from 12% (95% CI: 0.6-53%) in VLR-LR to 83% (66-93%) in HR while the corresponding values for the specificity were 92% (85-96%) and 63% (45-78%), respectively. Patients with false-negative mpMRI EPE prediction were more likely to have positive surgical margins in univariable (OR: 2.14; CI: 1.18, 3.87) as well as multivariable analysis adjusting for NCCN risk categories (OR: 1.97; CI: 1.08, 3.60).

Conclusions: The performance of mpMRI for prediction of EPE varies greatly between different NCCN risk categories with a low positive predicting value in patients at low to favorable intermediate risk and a low negative predictive value in patients at Unfavorable intermediate to high risk PCa. Given that mpMRI EPE misdiagnosis could have a negative impact on oncological and functional outcomes, NCCN risk categories should be considered when interpreting mpMRI findings in PCa patients.
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http://dx.doi.org/10.23736/S0393-2249.20.03688-7DOI Listing
December 2020

Staging Accuracy of Multiparametric Magnetic Resonance Imaging in Caucasian and African American Men Undergoing Radical Prostatectomy.

J Urol 2020 Jul 24;204(1):82-90. Epub 2020 Jan 24.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, New York.

Purpose: We compared the performance of multiparametric magnetic resonance imaging for the prediction of extraprostatic extension in African American and Caucasian American men and evaluated racial disparities in pathological outcomes after radical prostatectomy.

Materials And Methods: We identified 975 patients who underwent radical prostatectomy with preoperative multiparametric magnetic resonance imaging between January 2013 and April 2019 at our institution. Multivariable logistic regression analysis was performed predicting pathological extraprostatic extension, high grade prostate cancer (final pathology GGG [Gleason Grade Group] 3 or greater) in the overall population and pathological upgrading (final pathology GGG 3 or greater) in patients with a diagnosis of GGG 1-2 prostate cancer. Adverse pathology was defined as pT3 and/or GGG 3 or greater.

Results: A total of 221 (23%) patients were African American. Preoperatively 594 (60.9%) were GGG 1-2 (low risk group) and 381 (39.1%) GGG 3 or greater (high risk group). In the low risk group rates of pathological extraprostatic extension (18% vs 12.8%, p=0.14), adverse pathology (18% vs 13.4%, p=0.2) or upgrading (9.4% vs 12.1%, p=0.4) were similar between races. Similarly, in the high risk group there was no difference in rates of pathological extraprostatic extension. On multivariable analysis multiparametric magnetic resonance imaging predicted the presence of extraprostatic extension (OR 1.80, 95% CI 1.29-2.50) and high grade prostate cancer (OR 1.82, 95% CI 1.25-2.67) on final pathology. Conversely, race did not predict the outcomes of interest (all values p >0.05). Multiparametric magnetic resonance imaging showed comparable sensitivity (22.22% vs 27.84%), specificity (89.2% vs 79.2%), positive predictive value (89.2% vs 83.4%) and negative predictive value (89.2% vs 83.4%) between African American and Caucasian America men, respectively.

Conclusions: The accuracy of multiparametric magnetic resonance imaging in staging prostate cancer was similar in African American and Caucasian American patients and no difference was found between races in pathological outcomes after radical prostatectomy. These findings suggest that access to and use of advanced diagnostic tests may help mitigate prostate cancer racial disparities.
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http://dx.doi.org/10.1097/JU.0000000000000774DOI Listing
July 2020

Impact of biparametric prebiopsy prostate magnetic resonance imaging on the diagnostics of clinically significant prostate cancer in biopsy naïve men.

Scand J Urol 2020 Feb 9;54(1):7-13. Epub 2020 Jan 9.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

The objective of this study was to compare the prevalence of clinically significant prostate cancer (CSPCa) in men with biparametric prebiopsy prostate magnetic resonance imaging (MRI) and lesion-targeted biopsies (TBs) to the group of men without prebiopsy MRI in an initial biopsy session. The MRI group consists of men enrolled into four prospective clinical trials investigating a biparametric MRI (bpMRI) and TB while the non-MRI group was a retrospective cohort of men collected from an era prior to a clinical use of a prostate MRI. All men had standard biopsies (SBs). In the MRI group, men had additional TBs from potential cancer-suspicious lesions. CSPCa was defined as Gleason score ≥3 + 4 in any biopsy core taken. All the patients were prostate biopsy naïve. The MRI group consists of 507 while the non-MRI group 379 men. Mean age and prostate specific antigen (PSA) level differed significantly ( < 0.05) between the groups: In the MRI group, 64 years and 7.6 ng/ml, respectively, and in the non-MRI group 68 years and 8.2 ng/ml, respectively. Significantly ( < 0.05) more CSPCa was diagnosed with initial biopsies in the MRI group (48%) compared to non-MRI group (34%). In men with no CSPCa diagnosed during the initial biopsies, significantly fewer ( < 0.05) men had upgrading re-biopsies in the MRI group (5%) than in the non-MRI group (19%) during the follow up. Prebiopsy bpMRI with TBs combined with SBs could lead to earlier diagnoses of CSPCa compared with men without prebiopsy prostate MRI used in initial PCa diagnostics.
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http://dx.doi.org/10.1080/21681805.2019.1711161DOI Listing
February 2020

Does prostate magnetic resonance imaging (MRI) reporting system affect performance of MRI in men with a clinical suspicion of prostate cancer?

BJU Int 2020 01;125(1):4-5

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

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http://dx.doi.org/10.1111/bju.14960DOI Listing
January 2020

Qualitative and Quantitative Reporting of a Unique Biparametric MRI: Towards Biparametric MRI-Based Nomograms for Prediction of Prostate Biopsy Outcome in Men With a Clinical Suspicion of Prostate Cancer (IMPROD and MULTI-IMPROD Trials).

J Magn Reson Imaging 2020 05 21;51(5):1556-1567. Epub 2019 Nov 21.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Background: Multiparametric MRI of the prostate has been shown to improve the risk stratification of men with an elevated prostate-specific antigen (PSA). However, long acquisition time, high cost, and inter-center/reader variability of a routine prostate multiparametric MRI limit its wider adoption.

Purpose: To develop and validate nomograms based on unique rapid biparametric MRI (bpMRI) qualitative and quantitative derived variables for prediction of clinically significant cancer (SPCa).

Study Type: Retrospective analyses of single (IMPROD, NCT01864135) and multiinstitution trials (MULTI-IMPROD, NCT02241122).

Population: 161 and 338 prospectively enrolled men who completed the IMPROD and MULTI-IMPROD trials, respectively.

Field Strength/sequence: IMPROD bpMRI: 3T/1.5T, T -weighted imaging, three separate diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm ; 2) b values 0, 1500 s/mm ; 3) values 0, 2000 s/mm .

Assessment: The primary endpoint of the combined trial analysis was the diagnostic accuracy of the combination of IMPROD bpMRI and clinical variables for detection of SPCa.

Statistical Tests: Logistic regression models were developed using IMPROD trial data and validated using MULTI-IMPROD trial data. The model's performance was expressed as the area under the curve (AUC) values for the detection of SPCa, defined as ISUP Gleason Grade Group ≥2.

Results: A model incorporating clinical variables had an AUC (95% confidence interval) of 0.83 (0.77-0.89) and 0.80 (0.75-0.85) in the development and validation cohorts, respectively. The corresponding values for a model using IMPROD bpMRI findings were 0.93 (0.89-0.97), and 0.88 (0.84-0.92), respectively. Further addition of the quantitative DWI-based score did not improve AUC values (P < 0.05).

Data Conclusion: A prediction model using qualitative IMPROD bpMRI findings demonstrated high accuracy for predicting SPCa in men with an elevated PSA. Online risk calculator: http://petiv.utu.fi/multiimprod/ Level of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1556-1567.
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http://dx.doi.org/10.1002/jmri.26975DOI Listing
May 2020

Repeatability of radiomics and machine learning for DWI: Short-term repeatability study of 112 patients with prostate cancer.

Magn Reson Med 2020 06 8;83(6):2293-2309. Epub 2019 Nov 8.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Purpose: To evaluate repeatability of prostate DWI-derived radiomics and machine learning methods for prostate cancer (PCa) characterization.

Methods: A total of 112 patients with diagnosed PCa underwent 2 prostate MRI examinations (Scan1 and Scan2) performed on the same day. DWI was performed using 12 b-values (0-2000 s/mm ), post-processed using kurtosis function, and PCa areas were annotated using whole mount prostatectomy sections. A total of 1694 radiomic features including Sobel, Kirch, Gradient, Zernike Moments, Gabor, Haralick, CoLIAGe, Haar wavelet coefficients, 3D analogue to Laws features, 2D contours, and corner detectors were calculated. Radiomics and 4 feature pruning methods (area under the receiver operator characteristic curve, maximum relevance minimum redundancy, Spearman's ρ, Wilcoxon rank-sum) were evaluated in terms of Scan1-Scan2 repeatability using intraclass correlation coefficient (ICC)(3,1). Classification performance for clinically significant and insignificant PCa with Gleason grade groups 1 versus >1 was evaluated by area under the receiver operator characteristic curve in unseen random 30% data split.

Results: The ICC(3,1) values for conventional radiomics and feature pruning methods were in the range of 0.28-0.90. The machine learning classifications varied between Scan1 and Scan2 with % of same class labels between Scan1 and Scan2 in the range of 61-81%. Surface-to-volume ratio and corner detector-based features were among the most represented features with high repeatability, ICC(3,1) >0.75, consistently high ranking using all 4 feature pruning methods, and classification performance with area under the receiver operator characteristic curve >0.70.

Conclusion: Surface-to-volume ratio and corner detectors for prostate DWI led to good classification of unseen data and performed similarly in Scan1 and Scan2 in contrast to multiple conventional radiomic features.
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http://dx.doi.org/10.1002/mrm.28058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047644PMC
June 2020

Prostate Cancer Risk Stratification in Men With a Clinical Suspicion of Prostate Cancer Using a Unique Biparametric MRI and Expression of 11 Genes in Apparently Benign Tissue: Evaluation Using Machine-Learning Techniques.

J Magn Reson Imaging 2020 05 6;51(5):1540-1553. Epub 2019 Oct 6.

Institute of Biomedicine, University of Turku and Department of Pathology, Turku University Hospital, Turku, Finland.

Background: Accurate risk stratification of men with a clinical suspicion of prostate cancer (cSPCa) remains challenging despite the increasing use of MRI.

Purpose: To evaluate the diagnostic accuracy of a unique biparametric MRI protocol (IMPROD bpMRI) combined with clinical and molecular markers in men with cSPCa.

Study Type: Prospective single-institutional clinical trial (NCT01864135).

Subjects: Eighty men with cSPCa.

Field Strength/sequence: 3T, surface array coils. Two T -weighted and three diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm ; 2) b-values 0,1500 s/mm ; 3) b-values 0, 2000 s/mm .

Assessment: IMPROD bpMRI examinations were qualitatively (IMPROD bpMRI Likert score) and quantitatively (DWI-based Gleason grade score) prospectively reported. Men with IMPROD bpMRI Likert 3-5 had two targeted biopsies followed by 12-core systematic biopsies (SB); those with IMPROD bpMRI Likert 1-2 had only SB. Additionally, 2-core from normal-appearing prostate areas were obtained for the mRNA expression of ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2-ERG, and TDRD1 measured by quantitative reverse-transcription polymerase chain reaction.

Statistical Tests: Univariate and multivariate analysis using regularized least-squares, feature selection and tournament leave-pair-out cross-validation (TLPOCV), as well as 10 random splits of the data in training-testing sets, were used to evaluate the mRNA, clinical and IMPROD bpMRI parameters in detecting clinically significant prostate cancer (SPCa) defined as Gleason score ≥ 3 + 4. The evaluation metric was the area under the curve (AUC).

Results: IMPROD bpMRI Likert demonstrated the highest TLPOCV AUC of 0.92. The tested clinical variables had AUC 0.56-0.73, while the mRNA and additional IMPROD bpMRI parameters had AUC 0.50-0.67 and 0.65-0.89 respectively. The combination of clinical and mRNA biomarkers produced TLPOCV AUC of 0.87, the highest TLPOCV performance without including IMPROD bpMRI Likert.

Data Conclusion: The qualitative IMPROD bpMRI Likert score demonstrated the highest accuracy for SPCa detection compared with the tested clinical variables and mRNA biomarkers.

Level Of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1540-1553.
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http://dx.doi.org/10.1002/jmri.26945DOI Listing
May 2020

Prediction of biochemical recurrence in prostate cancer patients who underwent prostatectomy using routine clinical prostate multiparametric MRI and decipher genomic score.

J Magn Reson Imaging 2020 04 30;51(4):1075-1085. Epub 2019 Sep 30.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Background: Biochemical recurrence (BCR) affects a significant proportion of patients who undergo robotic-assisted laparoscopic prostatectomy (RALP).

Purpose: To evaluate the performance of a routine clinical prostate multiparametric magnetic resonance imaging (mpMRI) and Decipher genomic classifier score for prediction of biochemical recurrence in patients who underwent RALP.

Study Type: Retrospective cohort study.

Subjects: Ninety-one patients who underwent RALP performed by a single surgeon, had mpMRI before RALP, Decipher taken from RALP samples, and prostate specific antigen (PSA) follow-up for >3 years or BCR within 3 years, defined as PSA >0.2 mg/ml. FIELD STRENGTH/SEQUENCE: mpMRI was performed at 27 different institutions using 1.5T (n = 10) or 3T scanners and included T w, diffusion-weighted imaging (DWI), or dynamic contrast-enhanced (DCE) MRI.

Assessment: All mpMRI studies were reported by one reader using Prostate Imaging Reporting and Data System v. 2.1 (PI-RADsv2.1) without knowledge of other findings. Eighteen (20%) randomly selected cases were re-reported by reader B to evaluate interreader variability.

Statistical Tests: Univariate and multivariate analysis using greedy feature selection and tournament leave-pair-out cross-validation (TLPOCV) were used to evaluate the performance of various variables for prediction of BCR, which included clinical (three), systematic biopsy (three), surgical (six: RALP Gleason Grade Group [GGG], extracapsular extension, seminal vesicle invasion, intraoperative surgical margins [PSM], final PSM, pTNM), Decipher (two: Decipher score, Decipher risk category), and mpMRI (eight: prostate volume, PSA density, PI-RADv2.1 score, MRI largest lesion size, summed MRI lesions' volume and relative volume [MRI-lesion-percentage], mpMRI ECE, mpMRI seminal vesicle invasion [SVI]) variables. The evaluation metric was the area under the curve (AUC).

Results: Forty-eight (53%) patients developed BCR. The best-performing individual features with TLPOCV AUC of 0.73 (95% confidence interval [CI] 0.64-0.82) were RALP GGG, MRI-lesion-percentage followed by biopsy GGG (0.72, 0.62-0.82), and Decipher score (0.71, 0.60-0.82). The best performance was achieved by feature selection of Decipher+Surgery and MRI + Surgery variables with TLPOCV AUC of 0.82 and 0.81, respectively DATA CONCLUSION: Relative lesion volume measured on a routine clinical mpMRI failed to outperform Decipher score in BCR prediction.

Level Of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1075-1085.
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http://dx.doi.org/10.1002/jmri.26928DOI Listing
April 2020

Avoiding Unnecessary Magnetic Resonance Imaging (MRI) and Biopsies: Negative and Positive Predictive Value of MRI According to Prostate-specific Antigen Density, 4Kscore and Risk Calculators.

Eur Urol Oncol 2020 10 20;3(5):700-704. Epub 2019 Sep 20.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

The 2019 European Association of Urology guidelines recommend multiparametric magnetic resonance imaging (mpMRI) for biopsy-naïve patients with clinical suspicion of prostate cancer (PC) and avoiding biopsy in patients with negative mpMRI and low clinical suspicion. However, consensus on the optimal definition of low clinical suspicion is lacking. We evaluated 266 biopsy-naïve patients who underwent mpMRI, the 4Kscore test, and prostate biopsy to define the best strategy to avoid unnecessary testing and biopsies. The European Randomized Study of Screening for Prostate Cancer risk calculator (ERSPC-RC) and prostate-specific antigen density (PSAd) were also considered. For men with Prostate Imaging-Reporting and Data System v2.0 (PI-RADS) 1⿿2 lesions, the highest negative predictive value was observed for those with low or intermediate 4Kscore risk (96.9% and 97.1%), PSAd <0.10ng/ml/cm (98.7%), and ERSPC-RC <2% (98.7%). For men with PI-RADS 3⿿5 lesions the lowest positive predictive value was observed for those with low 4Kscore risk (0%), PSAd <0.10ng/ml/cm (13.2%), and ERSPC-RC <2% (12.3%). The best biopsy strategy was an initial 4Kscore followed by mpMRI if the 4Kscore was>7.5% and a subsequent biopsy if the mpMRI was positive (PI-RADS 3⿿5) or the 4Kscore was ⿥18%. This would result in missing 2.7% (2/74) of clinically significant PCs (csPCs) and avoiding 34.2% of biopsies. Initial mpMRI followed by biopsy for negative mpMRI (PI-RADS 1⿿2) if the 4Kscore was ⿥18% or PSAd was ⿥0.10ng/ml/cm resulted in a similar percentage of csPC missed (2.7% [2/74] and 1.3% [1/74]) but slightly fewer biopsies avoided (25.2% and 28.1%). Physicians should consider clinical risk screening tools when ordering and interpreting mpMRI results to avoid unnecessary testing and diagnostic errors. PATIENT SUMMARY: Performing the 4Kscore test in conjunction with multiparametric magnetic resonance imaging for men with a clinical suspicion of prostate cancer may help to reduce unnecessary biopsies.
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http://dx.doi.org/10.1016/j.euo.2019.08.015DOI Listing
October 2020

Prebiopsy IMPROD Biparametric Magnetic Resonance Imaging Combined with Prostate-Specific Antigen Density in the Diagnosis of Prostate Cancer: An External Validation Study.

Eur Urol Oncol 2020 10 6;3(5):648-656. Epub 2019 Sep 6.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Background: Biparametric magnetic resonance imaging (bpMRI) combined with prostate-specific antigen density (PSAd) may be an effective strategy for selecting men for prostate biopsy. It has been shown that performing biopsy only for men with bpMRI Likert scores of 4-5 or PSAd ≥0.15 ng/ml/cm is the most efficient strategy.

Objective: To externally validate previously published biopsy strategies using two prospective bpMRI trial cohorts.

Design, Setting, And Participants: After IMPROD bpMRI, 499 men had systematic transrectal prostate biopsies and men with IMPROD bpMRI Likert scores of 3-5 had an additional two to four targeted biopsies.

Outcome Measurements And Statistical Analysis: Various IMPROD bpMRI Likert score and PSAd thresholds were assessed using detection rates for significant prostate cancer (sPCa; Gleason score ≥3 + 4), predictive values, and proportion of biopsies avoided. Net benefits and decision curve analyses (DCA) were compared with the aim of finding an optimal strategy for sPCa detection. Combined biopsies were used for reference.

Results And Limitations: The negative predictive value (NPV) for sPCa in IMPROD bpMRI Likert 3-5 and 4-5 score groups was 93% and 92%, respectively, while the corresponding positive predictive value (PPV) was 57% and 72%, respectively. In DCA, the optimal combination was IMPROD bpMRI Likert score 4-5 or Likert 3 with PSAd ≥0.20 ng/ml/cm, which had NPV of 93% and PPV of 67%. Using this combination, 35% of the study patients would have avoided biopsies and 13 sPCas (6%, 13/229, of all sPCas diagnosed) would have been missed.

Conclusions: IMPROD bpMRI demonstrated a good NPV for sPCa. PSAd improved the NPV mainly among men with equivocal suspicion on IMPROD bpMRI. However, the additional value of PSAd was marginal: the NPV and PPV for IMPROD bpMRI Likert 4-5 score group were 92% and 72%, respectively, while the corresponding values for the best combination strategy were 93% and 67%.

Patient Summary: We investigated a rapid prostate magnetic resonance imaging protocol (IMPROD bpMRI) combined with prostate-specific antigen (PSA) density for detection of significant prostate cancer. Our results show that IMPROD bpMRI is a good diagnostic tool, but the additional value provided by PSA density is marginal.
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http://dx.doi.org/10.1016/j.euo.2019.08.008DOI Listing
October 2020

Radiomics and machine learning of multisequence multiparametric prostate MRI: Towards improved non-invasive prostate cancer characterization.

PLoS One 2019 8;14(7):e0217702. Epub 2019 Jul 8.

Dept. of Diagnostic Radiology, University of Turku, Turku, Finland.

Purpose: To develop and validate a classifier system for prediction of prostate cancer (PCa) Gleason score (GS) using radiomics and texture features of T2-weighted imaging (T2w), diffusion weighted imaging (DWI) acquired using high b values, and T2-mapping (T2).

Methods: T2w, DWI (12 b values, 0-2000 s/mm2), and T2 data sets of 62 patients with histologically confirmed PCa were acquired at 3T using surface array coils. The DWI data sets were post-processed using monoexponential and kurtosis models, while T2w was standardized to a common scale. Local statistics and 8 different radiomics/texture descriptors were utilized at different configurations to extract a total of 7105 unique per-tumor features. Regularized logistic regression with implicit feature selection and leave pair out cross validation was used to discriminate tumors with 3+3 vs >3+3 GS.

Results: In total, 100 PCa lesions were analysed, of those 20 and 80 had GS of 3+3 and >3+3, respectively. The best model performance was obtained by selecting the top 1% features of T2w, ADCm and K with ROC AUC of 0.88 (95% CI of 0.82-0.95). Features from T2 mapping provided little added value. The most useful texture features were based on the gray-level co-occurrence matrix, Gabor transform, and Zernike moments.

Conclusion: Texture feature analysis of DWI, post-processed using monoexponential and kurtosis models, and T2w demonstrated good classification performance for GS of PCa. In multisequence setting, the optimal radiomics based texture extraction methods and parameters differed between different image types.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217702PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6613688PMC
February 2020

Validation of IMPROD biparametric MRI in men with clinically suspected prostate cancer: A prospective multi-institutional trial.

PLoS Med 2019 06 3;16(6):e1002813. Epub 2019 Jun 3.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Background: Magnetic resonance imaging (MRI) combined with targeted biopsy (TB) is increasingly used in men with clinically suspected prostate cancer (PCa), but the long acquisition times, high costs, and inter-center/reader variability of routine multiparametric prostate MRI limit its wider adoption.

Methods And Findings: The aim was to validate a previously developed unique MRI acquisition and reporting protocol, IMPROD biparametric MRI (bpMRI) (NCT01864135), in men with a clinical suspicion of PCa in a multi-institutional trial (NCT02241122). IMPROD bpMRI has average acquisition time of 15 minutes (no endorectal coil, no intravenous contrast use) and consists of T2-weighted imaging and 3 separate diffusion-weighed imaging acquisitions. Between February 1, 2015, and March 31, 2017, 364 men with a clinical suspicion of PCa were enrolled at 4 institutions in Finland. Men with an equivocal to high suspicion (IMPROD bpMRI Likert score 3-5) of PCa had 2 TBs of up to 2 lesions followed by a systematic biopsy (SB). Men with a low to very low suspicion (IMPROD bpMRI Likert score 1-2) had only SB. All data and protocols are freely available. The primary outcome of the trial was diagnostic accuracy-including overall accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value-of IMPROD bpMRI for clinically significant PCa (SPCa), which was defined as a Gleason score ≥ 3 + 4 (Gleason grade group 2 or higher). In total, 338 (338/364, 93%) prospectively enrolled men completed the trial. The accuracy and NPV of IMPROD bpMRI for SPCa were 70% (113/161) and 95% (71/75) (95% CI 87%-98%), respectively. Restricting the biopsy to men with equivocal to highly suspicious IMPROD bpMRI findings would have resulted in a 22% (75/338) reduction in the number of men undergoing biopsy while missing 4 (3%, 4/146) men with SPCa. The main limitation is uncertainty about the true PCa prevalence in the study cohort, since some of the men may have PCa despite having negative biopsy findings.

Conclusions: IMPROD bpMRI demonstrated a high NPV for SPCa in men with a clinical suspicion of PCa in this prospective multi-institutional clinical trial.

Trial Registration: ClinicalTrials.gov NCT02241122.
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http://dx.doi.org/10.1371/journal.pmed.1002813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6546206PMC
June 2019

Correlation between F-1-amino-3-fluorocyclobutane-1-carboxylic acid (F-fluciclovine) uptake and expression of alanine-serine-cysteine-transporter 2 (ASCT2) and L-type amino acid transporter 1 (LAT1) in primary prostate cancer.

EJNMMI Res 2019 May 31;9(1):50. Epub 2019 May 31.

Turku PET Centre, Turku, Finland.

Purpose: To evaluate the expression of alanine-serine-cysteine-transporter 2 (ASCT2) and L-type amino acid transporter1 (LAT1) in prostate cancer (PCa) and their impact on uptake of F-1-amino-3-fluorocyclobutane-1-carboxylic acid (F-fluciclovine) which is approved for the detection of recurrent PCa.

Methods: Twenty-five hormone-naïve patients with histologically confirmed PCa underwent PET/CT before prostatectomy. Dynamic imaging was performed immediately after injection of 368 ± 10 MBq of F-fluciclovine and the uptake in PCa was expressed as SUV at six sequential 4-min time frames and as tracer distribution volume (V) using Logan plots over 0-24 min. The expression of ASCT2 and LAT1 was studied with immunohistochemistry (IHC) on a tissue microarray (TMA) containing three cores per carcinoma lesion. The TMA slides were scored independently by two trained readers based on visual intensity of ASCT2/LAT1 expression on a four-tiered scale. The correlations between ASCT2/LAT1 staining intensity, SUVmax/V, and Gleason grade group (GGG) were assessed using Spearman's rank correlation coefficient (ρ).

Results: Forty tumor foci (> 0.5 mm in diameter, max. 3 per patient) were available for TMA. In visual scoring, low, moderate, and high staining intensity of ASCT2 was observed in 4 (10%), 24 (60%), and 12 (30%) tumors, respectively. No tumors showed high LAT1 staining intensity while moderate intensity was found in 10 (25%), 25 (63%) showed low, and the remaining 5 (12%) were negative for staining with LAT1. Tumors with GGG > 2 showed significantly higher uptake of F-fluciclovine and higher LAT1 staining intensity (p < 0.05). The uptake of F-fluciclovine correlated significantly with LAT1 expression (ρ = 0.39, p = 0.01, for SUV at 2 min and ρ = 0.39, p = 0.01 for V). No correlation between ASCT2 expression and F-fluciclovine uptake or GGG was found.

Conclusions: Our findings suggest that LAT1 is moderately associated with the transport of F-fluciclovine in local PCa not exposed to hormonal therapy. Both high and low Gleason grade tumors express ASCT2 while LAT1 expression is less conspicuous and may be absent in some low-grade tumors. Our observations may be of importance when using F-fluciclovine imaging in the planning of focal therapies for PCa.
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http://dx.doi.org/10.1186/s13550-019-0518-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544711PMC
May 2019

IMPROD biparametric MRI in men with a clinical suspicion of prostate cancer (IMPROD Trial): Sensitivity for prostate cancer detection in correlation with whole-mount prostatectomy sections and implications for focal therapy.

J Magn Reson Imaging 2019 11 22;50(5):1641-1650. Epub 2019 Mar 22.

Institute of Biomedicine, University of Turku and Department of Pathology, Turku University Hospital, Turku, Finland.

Background: Prostate MRI is increasingly being used in men with a clinical suspicion of prostate cancer (PCa). However, development and validation of methods for focal therapy planning are still lagging.

Purpose: To evaluate the diagnostic accuracy on lesion, region-of-interest (ROI), and voxel level of IMPROD biparametric prostate MRI (bpMRI) for PCa detection in men with a clinical suspicion of PCa who subsequently underwent radical prostatectomy.

Study Type: Prospective single-institution clinical trial (NCT01864135).

Population: Sixty-four men who underwent radical prostatectomy after IMPROD bpMRI performed in prebiopsy settings.

Field Strength/sequence: IMPROD bpMRI consisted of T -weighted imaging (T w) and three separate diffusion-weighted imaging acquisitions with an average acquisition time of 15 minutes.

Assessment: The diagnostic accuracy of prospectively reported manual cancer delineations and regions increased with 3D dilation were evaluated on the voxel level (volume of 1.17 mm , 1 mm , 125 mm ) as well as the 36 ROI level. Only PCa lesions with a diameter ≥ 5 mm or any Gleason Grade 4 were analyzed. All data and protocols are freely available at: http://petiv.utu.fi/improd STATISTICAL TESTS: Sensitivity, specificity, accuracy.

Results: In total, 99 PCa lesions were identified. Forty (40%, 40/99) had a Gleason score (GS) of >3 + 4. Twenty-eight PCa lesions (28%, 28/99) were missed by IMPROD bpMRI, three (7.5%, 3/40) with GS >3 + 4. 3D dilation of manual cancer delineations in all directions by ~10-12 mm (corresponding to the Hausdorff distance) was needed to achieve sensitivity approaching 100% on a voxel level.

Data Conclusion: IMPROD bpMRI had a high sensitivity on lesion level for PCa with GS >3 + 4. Increasing 3D lesion delineations by ~10-12 mm (corresponding to the Hausdorff distance) was needed to achieve high sensitivity on the voxel level. Such information may help in planning ablation therapies.

Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1641-1650.
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http://dx.doi.org/10.1002/jmri.26727DOI Listing
November 2019

Comparison of standardized uptake values between Tc-HDP SPECT/CT and F-NaF PET/CT in bone metastases of breast and prostate cancer.

EJNMMI Res 2019 Jan 24;9(1). Epub 2019 Jan 24.

Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland.

Background: Despite recent technological advances allowing for quantitative single-photon emission computed tomography (SPECT), quantitative SPECT has not been widely used in the clinical practice. The aim of this study is to evaluate the feasibility of quantitative SPECT for measuring metastatic bone uptake in breast and prostate cancer by comparing standard uptake values (SUVs) measured with Tc-HDP SPECT/CT and F-NaF PET/CT.

Methods: Twenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent both Tc-HDP SPECT/CT and F-NaF PET/CT within 14 days of each other. The SPECT and PET data were reconstructed using ordered-subset expectation-maximization algorithms achieving quantitative images. Metastatic and benign skeletal lesions visible in both data sets were identified, and their maximum, peak, and mean SUVs (SUV, SUV, and SUV) were determined. SUV ratios (SUVRs) between the lesions and adjacent normal appearing bone were also calculated. Linear regression was used to evaluate the correlations between the SUVs of SPECT and PET and Bland-Altman plots to evaluate the differences between the SUVs and SUVRs of SPECT and PET.

Results: A total of 231 skeletal lesions, 129 metastatic and 102 benign, were analyzed. All three SUV measures correlated very strongly between SPECT and PET (R ≥ 0.80, p < 0.001) when all lesions were included, and the PET SUVs were significantly higher than SPECT SUVs (p < 0.001). The median differences were 21%, 12%, and 19% for SUV, SUV, and SUV, respectively. On the other hand, the SUVRs were similar between SPECT and PET with median differences of 2%, - 9%, and 2% for SUVR, SUVR, and SUVR, respectively.

Conclusion: The strong correlation between SUVs and similar SUVRs of Tc-HDP SPECT/CT and F-NaF PET/CT demonstrate that SPECT is an applicable tool for clinical quantification of bone metabolism in osseous metastases in breast and prostate cancer patients.
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http://dx.doi.org/10.1186/s13550-019-0475-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6346696PMC
January 2019

Tournament leave-pair-out cross-validation for receiver operating characteristic analysis.

Stat Methods Med Res 2019 Oct-Nov;28(10-11):2975-2991. Epub 2018 Aug 20.

Department of Future Technologies, University of Turku, Turku, Finland.

Receiver operating characteristic analysis is widely used for evaluating diagnostic systems. Recent studies have shown that estimating an area under receiver operating characteristic curve with standard cross-validation methods suffers from a large bias. The leave-pair-out cross-validation has been shown to correct this bias. However, while leave-pair-out produces an almost unbiased estimate of area under receiver operating characteristic curve, it does not provide a ranking of the data needed for plotting and analyzing the receiver operating characteristic curve. In this study, we propose a new method called tournament leave-pair-out cross-validation. This method extends leave-pair-out by creating a tournament from pair comparisons to produce a ranking for the data. Tournament leave-pair-out preserves the advantage of leave-pair-out for estimating area under receiver operating characteristic curve, while it also allows performing receiver operating characteristic analyses. We have shown using both synthetic and real-world data that tournament leave-pair-out is as reliable as leave-pair-out for area under receiver operating characteristic curve estimation and confirmed the bias in leave-one-out cross-validation on low-dimensional data. As a case study on receiver operating characteristic analysis, we also evaluate how reliably sensitivity and specificity can be estimated from tournament leave-pair-out receiver operating characteristic curves.
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http://dx.doi.org/10.1177/0962280218795190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6745617PMC
December 2020