Rethinking prostate cancer screening: could MRI be an alternative screening test?

Lifetime Health and Economic Outcomes of Biparametric Magnetic Resonance Imaging as First-Line Screening for Prostate Cancer : A Decision Model Analysis

BACKGROUND

Contemporary prostate cancer (PCa) screening uses first-line prostate-specific antigen (PSA) testing, possibly followed by multiparametric magnetic resonance imaging (mpMRI) for men with elevated PSA levels. First-line biparametric MRI (bpMRI) screening has been proposed as an alternative.

OBJECTIVE

To evaluate the comparative effectiveness and cost-effectiveness of first-line bpMRI versus PSA-based screening.

DESIGN

Decision analysis using a microsimulation model.

DATA SOURCES

Surveillance, Epidemiology, and End Results database; randomized trials.

TARGET POPULATION

U.S. men aged 55 years with no prior screening or PCa diagnosis.

TIME HORIZON

Lifetime.

PERSPECTIVE

U.S. health care system.

INTERVENTION

Biennial screening to age 69 years using first-line PSA testing (test-positive threshold, 4 µg/L) with or without second-line mpMRI or first-line bpMRI (test-positive threshold, PI-RADS [Prostate Imaging Reporting and Data System] 3 to 5 or 4 to 5), followed by biopsy guided by MRI or MRI plus transrectal ultrasonography.

OUTCOME MEASURES

Screening tests, biopsies, diagnoses, overdiagnoses, treatments, PCa deaths, quality-adjusted and unadjusted life-years saved, and costs.

RESULTS OF BASE-CASE ANALYSIS

For 1000 men, first-line bpMRI versus first-line PSA testing prevented 2 to 3 PCa deaths and added 10 to 30 life-years (4 to 11 days per person) but increased the number of biopsies by 1506 to 4174 and the number of overdiagnoses by 38 to 124 depending on the biopsy imaging scheme. At conventional cost-effectiveness thresholds, first-line PSA testing with mpMRI followed by either biopsy approach for PI-RADS 4 to 5 produced the greatest net monetary benefits.

RESULTS OF SENSITIVITY ANALYSIS

First-line PSA testing remained more cost-effective even if bpMRI was free, all men with low-risk PCa underwent surveillance, or screening was quadrennial.

LIMITATION

Performance of first-line bpMRI was based on second-line mpMRI data.

CONCLUSION

Decision analysis suggests that comparative effectiveness and cost-effectiveness of PCa screening are driven by false-positive results and overdiagnoses, favoring first-line PSA testing with mpMRI over first-line bpMRI.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Dual-mode fluorescence and colorimetric smartphone-based sensing platform with oxidation-induced self-assembled nanoflowers for sarcosine detection

BACKGROUND

Early prostatic cancer (PCa) diagnosis significantly improves the chances of successful treatment and enhances patient survival rates. Traditional enzyme cascade-based early cancer detection methods offer efficiency and signal amplification but are limited by cost, complexity, and enzyme dependency, affecting stability and practicality. Meanwhile, sarcosine (Sar) is commonly considered a biomarker for PCa development. It is essential to develop a Sar detection method based on cascade reactions, which should be efficient, low skill requirement, and suitable for on-site testing.

RESULTS

To address this, our study introduces the synthesis of organic-inorganic self-assembled nanoflowers to optimize existing detection methods. The Sar oxidase (SOX)-inorganic hybrid nanoflowers (Cu3(PO4)2:Ce@SOX) possess inherent fluorescent properties and excellent peroxidase activity, coupled with efficient enzyme loading. Based on this, we have developed a dual-mode multi-enzyme cascade nanoplatform combining fluorescence and colorimetric methods for the detection of Sar. The encapsulation yield of Cu3(PO4)2:Ce@SOX reaches 84.5 %, exhibiting a remarkable enhancement in catalytic activity by 1.26-1.29 fold compared to free SOX. The present study employing a dual-signal mechanism encompasses 'turn-off' fluorescence signals ranging from 0.5 μM to 60 μM, with a detection limit of 0.226 μM, and 'turn-on' colorimetric signals ranging from 0.18 μM to 60 μM, with a detection limit of 0.120 μM.

SIGNIFICANCE

Furthermore, our study developed an intelligent smartphone sensor system utilizing cotton swabs for real-time analysis of Sar without additional instruments. The nano-platform exhibits exceptional repeatability and stability, rendering it well-suited for detecting Sar in authentic human urine samples. This innovation allows for immediate analysis, offering valuable insights for portable and efficient biosensors applicable to Sar and other analytes.

Biparametric MRI in prostate cancer during active surveillance: is it safe?

Active surveillance (AS) is the preferred option for patients presenting with low-intermediate-risk prostate cancer. MRI now plays a crucial role for baseline assessment and ongoing monitoring of AS. The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations aid radiological assessment of progression; however, current guidelines do not advise on MRI protocols nor on frequency. Biparametric (bp) imaging without contrast administration offers advantages such as reduced costs and increased throughput, with similar outcomes to multiparametric (mp) MRI shown in the biopsy naïve setting. In AS follow-up, the paradigm shifts from MRI lesion detection to assessment of progression, and patients have the further safety net of continuing clinical surveillance. As such, bpMRI may be appropriate in clinically stable patients on routine AS follow-up pathways; however, there is currently limited published evidence for this approach. It should be noted that mpMRI may be mandated in certain patients and potentially offers additional advantages, including improving image quality, new lesion detection, and staging accuracy. Recently developed AI solutions have enabled higher quality and faster scanning protocols, which may help mitigate against disadvantages of bpMRI. In this article, we explore the current role of MRI in AS and address the need for contrast-enhanced sequences. CLINICAL RELEVANCE STATEMENT: Active surveillance is the preferred plan for patients with lower-risk prostate cancer, and MRI plays a crucial role in patient selection and monitoring; however, current guidelines do not currently recommend how or when to perform MRI in follow-up. KEY POINTS: Noncontrast biparametric MRI has reduced costs and increased throughput and may be appropriate for monitoring stable patients. Multiparametric MRI may be mandated in certain patients, and contrast potentially offers additional advantages. AI solutions enable higher quality, faster scanning protocols, and could mitigate the disadvantages of biparametric imaging.

Key learning on the promise and limitations of MRI in prostate cancer screening

MRI retains its ability to reduce the harm of prostate biopsies by decreasing biopsy rates and the detection of indolent cancers in population-based screening studies aiming to find clinically significant prostate cancers. Limitations of low positive predictive values and high reader variability in diagnostic performance require optimisations in patient selection, imaging protocols, interpretation standards, diagnostic thresholds, and biopsy methods. Improvements in diagnostic accuracy could come about through emerging technologies like risk calculators and polygenic risk scores to select men for MRI. Furthermore, artificial intelligence and workflow optimisations focused on streamlining the diagnostic pathway, quality control, and assurance measures will improve MRI variability. CLINICAL RELEVANCE STATEMENT: MRI significantly reduces harm in prostate cancer screening, lowering unnecessary biopsies and minimizing the overdiagnosis of indolent cancers. MRI maintains the effective detection of high-grade cancers, thus improving the overall benefit-to-harm ratio in population-based screenings with or without using serum prostate-specific antigen (PSA) for patient selection. KEY POINTS: • The use of MRI enables the harm reduction benefits seen in individual early cancer detection to be extended to both risk-stratified and non-stratified prostate cancer screening populations. • MRI limitations include a low positive predictive value and imperfect reader variability, which require standardising interpretations, biopsy methods, and integration into a quality diagnostic pathway. • Current evidence is based on one-time point use of MRI in screening; MRI effectiveness in multiple rounds of screening is not well-documented.

Prostagram magnetic resonance imaging in a screening population: Prostate Imaging-Reporting and Data System or Likert?

OBJECTIVE

To compare biopsy recommendation rates and accuracy of the Prostate Imaging-Reporting and Data System, version 2 (PI-RADSv2) with the Likert scale for detection of clinically significant and insignificant prostate cancer in men screened within the Imperial Prostate 1 Prostate Cancer Screening Trial Using Imaging (IP1-PROSTAGRAM).

PATIENTS AND METHODS

Men aged 50-69 years were screened with Prostagram MRI. Scans were prospectively reported using both PI-RADSv2 (excluding dynamic contrast-enhanced sequence score) and 5-point Likert scores by expert uro-radiologists. Systematic and targeted transperineal biopsy was recommended if the scan was scored ≥ 3, based on either reporting system. The proportion of patients recommended for biopsy and detection rates for Grade Groups (GGs) 1 and ≥ 2 were compared. Receiver operating characteristic (ROC) analysis was performed to compare performance.

RESULTS

A total of 406 men underwent Prostagram MRI. The median (interquartile range) age and prostate-specific antigen level were 57 (53-61) years and 0.91 (0.56-1.74) ng/mL, respectively. At MRI score ≥ 3, more patients were recommended for biopsy based on Likert criteria (94/406; 23%, 95% confidence interval [CI] 19.2%-27.6%) compared to PI-RADSv2 (72/406; 18%, 95% CI 14.2%-21.9%; P = 0.03). For MRI scores ≥ 4, PI-RADSv2 and Likert scales led to 43/406 (11%, 95% CI 7.9%-14.1%) and 35/406 (9%, 95% CI 6.2%-11.9%) men recommended for biopsy (P = 0.40). For GG ≥ 2 detection, PIRADSv2 and Likert detected 22% (95% CI 11.4%-30.8%, 14/72) and 16% (95% CI 9.5%-25.3%, 15/94), respectively (P = 0.56). For GG1 cancers detection these were 11% (95% CI 4.3%-19.6%, seven of 72) vs 11% (95% CI 4.7%-17.8%, nine of 94; P = 1.00). The accuracy of PI-RADSv2 and Likert scale was similar (area under the ROC curve 0.64 vs 0.65, P = 0.95).

CONCLUSIONS

In reporting non-contrast-enhanced Prostagram MRI in a screening population, the PI-RADSv2 and Likert scoring systems were equally accurate; however, Likert scale use led to more men undergoing biopsy without a subsequent increase in significant cancer detection rates. To improve reporting of Prostagram MRI, either the PI-RADSv2 or a modified Likert scale or a standalone scoring system should be developed.

Development and validation of a novel nomogram predicting clinically significant prostate cancer in biopsy-naive men based on multi-institutional analysis

BACKGROUND

Prediction of clinically significant prostate cancer (csPCa) is essential to select biopsy-naive patients for prostate biopsy. This study was to develop and validate a nomogram based on clinicodemographic parameters and exclude csPCa using prostate-specific antigen density (PSAD) stratification.

METHODS

Independent predictors were determined via univariate and multivariate logistic analysis and adopted for developing a predictive nomogram, which was assessed in terms of discrimination, calibration, and net benefit. Different PSAD thresholds were used for deciding immediate biopsies in patients with Prostate Imaging-Reporting and Data System (PI-RADS) 3 lesions.

RESULTS

A total of 932 consecutive patients who underwent ultrasound-guided transperineal cognitive biopsy were enrolled in our study. In the development cohort, age (odds ratio [OR], 1.075; 95% confidence interval [CI], 1.036-1.114), PSAD (OR, 6.003; 95% CI, 2.826-12.751), and PI-RADS (OR, 3.419; 95% CI, 2.453-4.766) were significant predictors for csPCa. On internal and external validation, this nomogram showed high areas under the curve of 0.943, 0.922, and 0.897, and low Brier scores of 0.092, 0.102, and 0.133 and insignificant unreliability tests of 0.713, 0.490, and 0.859, respectively. Decision curve analysis revealed this model could markedly improve clinical net benefit. The probability of excluding csPCa was 98.51% in patients with PI-RADS 3 lesions and PSAD <0.2 ng/ml2 .

CONCLUSION

This novel nomogram including age, PSAD, and PI-RADS could be applied to accurately predict csPCa, and 44.08% of patients with equivocal imaging findings plus PSAD <0.2 ng/ml2 could safely forgo biopsy.

Prostate cancer screening-stepping forward with MRI

OBJECTIVE

To comprehensively review the literature on the integration of MRI as a diagnostic tool in prostate cancer screening and offer practical recommendations for optimising its use.

METHODS

Existing research studies, clinical guidelines and expert opinions were reviewed to support the optimisation standards for MRI use in screening. Consolidated screening principles were used to make appropriate recommendations regarding the integration of MRI into the diagnostic pathway.

RESULTS

To strike a balance between the potential benefits of early detection on mortality and minimising the harm of over-diagnosing indolent cancers, it is necessary to have a clear understanding of the context of MRI use. The key to optimisation is patient selections and MRI-targeted biopsies. For men at higher-than-average risk, it is essential to use screening-specific MRI protocols and establish accuracy levels and interpretation criteria. Optimisation of readings by the automation of data acquisition, image quality monitoring, post-processing, radiologist certification and deep-learning computer-aided software is needed. The optimal utilisation of MRI involves its integration into a multistep diagnostic pathway, supported by a quality-assured and cost-effective infrastructure that ensures community-wide access to imaging.

CONCLUSION

MRI in the prostate cancer screening pathway can bring substantial diagnostic benefits. By carefully considering its advantages, limitations and safety concerns and integrating it into a multistep diagnostic pathway, clinicians can improve outcomes while minimising harm to screening participants.

CLINICAL RELEVANCE STATEMENT

The manuscript discusses the role of MRI in prostate cancer screening, highlighting its potential to improve accuracy and reduce overdiagnosis. It emphasises the importance of optimising protocols and integrating MRI into a multistep diagnostic pathway for successfully delivering screening benefits.

KEY POINTS

• Population screening for prostate cancer is a new indication for prostate MRI that allows the detection of high-risk cancers while reducing the need for biopsies and associated harm. • To optimise prostate cancer screening using MRI, it is essential to redefine MRI protocols; establish accuracy levels, reliability and interpretation criteria; and optimise reading (including post-processing, image quality, radiologist certification, and deep-learning computer-aided software). • The optimal utilisation of MRI for prostate cancer screening would involve its integration into a multistep diagnostic pathway, supported by a quality-assured and cost-effective infrastructure that ensures community-wide access to imaging.

Re-evaluating the diagnostic efficacy of PSA as a referral test to detect clinically significant prostate cancer in contemporary MRI-based image-guided biopsy pathways

Introduction

Modern image-guided biopsy pathways at diagnostic centres have greatly refined the investigations of men referred with suspected prostate cancer. However, the referral criteria from primary care are still based on historical prostate-specific antigen (PSA) cut-offs and age-referenced thresholds. Here, we tested whether better contemporary pathways and biopsy methods had improved the predictive utility value of PSA referral thresholds.

Methods

PSA referral thresholds, age-referenced ranges and PSA density (PSAd) were assessed for positive predictive value (PPV) in detection of clinically significant prostate cancer (csPCa - histological ⩾ Grade Group 2). Data were analysed from men referred to three diagnostics centres who used multi-parametric magnetic resonance imaging (mpMRI)-guided prostate biopsies for disease characterisation. Findings were validated in a separate multicentre cohort. Results: Data from 2767 men were included in this study. The median age, PSA and PSAd were 66.4 years, 7.3 ng/mL and 0.1 ng/mL2, respectively. Biopsy detected csPCa was found in 38.7%. The overall area under the curve (AUC) for PSA was 0.68 which is similar to historical performance. A PSA threshold of ⩾ 3 ng/mL had a PPV of 40.3%, but this was age dependent (PPV: 24.8%, 32.7% and 56.8% in men 50-59 years, 60-69 years and ⩾ 70 years, respectively). Different PSA cut-offs and age-reference ranges failed to demonstrate better performance. PSAd demonstrated improved AUC (0.78 vs 0.68, p < 0.0001) and improved PPV compared to PSA. A PSAd of ⩾ 0.10 had a PPV of 48.2% and similar negative predictive value (NPV) to PSA ⩾ 3 ng/mL and out-performed PSA age-reference ranges. This improved performance was recapitulated in a separate multi-centre cohort (n = 541).

Conclusion

The introduction of MRI-based image-guided biopsy pathways does not appear to have altered PSA diagnostic test characteristics to positively detect csPCa. We find no added value to PSA age-referenced ranges, while PSAd offers better PPV and the potential for a single clinically useful threshold (⩾0.10) for all age groups.

Level of evidence

IV.

An Evaluation of Screening Pathways Using a Combination of Magnetic Resonance Imaging and Prostate-specific Antigen: Results from the IP1-PROSTAGRAM Study

BACKGROUND

The use of prostate-specific antigen (PSA) testing to screen for prostate cancer has been fraught with under- and overdiagnosis. Short, noncontrast magnetic resonance imaging (MRI) might detect more grade group ≥2 cancers with similar rates of biopsy.

OBJECTIVE

To evaluate strategies that combined PSA and MRI to select men based in the community for a prostate biopsy.

DESIGN, SETTING, AND PARTICIPANTS

IP1-PROSTAGRAM was a prospective, population-based, paired cohort study of 408 men aged 50-69 yr conducted at seven UK primary care practice and two imaging centres (from October 10, 2018 to May 15, 2019).

INTERVENTION

All participants underwent screening with a PSA test, MRI (T2-weighted and diffusion), and transrectal ultrasound (b-mode and elastography). If any test was screen positive, a systematic 12-core biopsy was performed. Additional image-fusion targeted biopsies were taken if the MRI or ultrasound was positive.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We conducted an analysis, set out in the statistical plan a priori, comparing 13 different pathways including PSA-alone, MRI-alone, and a range of PSA thresholds and MRI scores. The performance of each pathway was evaluated focusing on the trade-offs between biopsy referral rates and detection of grade group ≥2 cancers. A targeted biopsy was performed only where the PROSTAGRAM MRI showed a lesion score of 3, 4, or 5.

RESULTS AND LIMITATIONS

The standard PSA pathway (PSA ≥3 ng/ml + systematic biopsy) would lead to 10% of men being referred for a biopsy and a 1.0% detection rate of grade group ≥2 cancers. Pathways that relied on MRI alone set at a threshold score of 3 for a biopsy led to higher biopsy rates, but with benefit of high cancer detection rates. The pathway that combined an initial low PSA threshold (≥1.0 ng/ml) and MRI score ≥4 accurately identified a high rate of grade group ≥2 cancers (2.5%, 95% confidence interval 1.3-4.6) while recommending fewer patients for a biopsy (7.1%, 95% confidence interval 4.9-10.2). The results are pertinent to only one screening round, the impact of repeat screening rounds is not evaluated, and the required MRI capacity is currently lacking.

CONCLUSIONS

Our results highlight the trade-off that exists between reducing excessive numbers of biopsies and maintaining grade group ≥2 cancer detection rates. A pathway that combines PSA ≥1 ng/ml and MRI score ≥4 maintains the detection of grade group ≥2 cancers while recommending fewer men for biopsies and would be the preferred strategy to evaluate in future studies at the first screening round.

PATIENT SUMMARY

The IP1-PROSTAGRAM study shows that PROSTAGRAM magnetic resonance imaging in men with a prostate-specific antigen level of ≥1.0 ng/ml could be a promising pathway to evaluate in future screening trials.

3D magnetic resonance fingerprinting on a low-field 50 mT point-of-care system prototype: evaluation of muscle and lipid relaxation time mapping and comparison with standard techniques

OBJECTIVE

To implement magnetic resonance fingerprinting (MRF) on a permanent magnet 50 mT low-field system deployable as a future point-of-care (POC) unit and explore the quality of the parameter maps.

MATERIALS AND METHODS

3D MRF was implemented on a custom-built Halbach array using a slab-selective spoiled steady-state free precession sequence with 3D Cartesian readout. Undersampled scans were acquired with different MRF flip angle patterns and reconstructed using matrix completion and matched to the simulated dictionary, taking excitation profile and coil ringing into account. MRF relaxation times were compared to that of inversion recovery (IR) and multi-echo spin echo (MESE) experiments in phantom and in vivo. Furthermore, B₀ inhomogeneities were encoded in the MRF sequence using an alternating TE pattern, and the estimated map was used to correct for image distortions in the MRF images using a model-based reconstruction.

RESULTS

Phantom relaxation times measured with an optimized MRF sequence for low field were in better agreement with reference techniques than for a standard MRF sequence. In vivo muscle relaxation times measured with MRF were longer than those obtained with an IR sequence (T₁: 182 ± 21.5 vs 168 ± 9.89 ms) and with an MESE sequence (T₂: 69.8 ± 19.7 vs 46.1 ± 9.65 ms). In vivo lipid MRF relaxation times were also longer compared with IR (T₁: 165 ± 15.1 ms vs 127 ± 8.28 ms) and with MESE (T₂: 160 ± 15.0 ms vs 124 ± 4.27 ms). Integrated ΔB₀ estimation and correction resulted in parameter maps with reduced distortions.

DISCUSSION

It is possible to measure volumetric relaxation times with MRF at 2.5 × 2.5 × 3.0 mm³ resolution in a 13 min scan time on a 50 mT permanent magnet system. The measured MRF relaxation times are longer compared to those measured with reference techniques, especially for T₂. This discrepancy can potentially be addressed by hardware, reconstruction and sequence design, but long-term reproducibility needs to be further improved.

Monoparametric high-resolution diffusion weighted MRI as a possible first step in an MRI-directed diagnostic pathway for men with suspicion of prostate cancer

Purpose

To explore if a high-resolution diffusion weighted MRI sequence (DWI-only) could be used as a first step in an MRI-directed diagnostic pathway.

Methods

Prospective single center study that between December 2017 and August 2018 included 129 consecutive patients with suspicion of prostate cancer into a PI-RADS-based MRI-directed diagnostic pathway. All patients had multiparametric MRI (mpMRI). Based on only the transversal high-resolution DWI images two consultant radiologists prospectively categorized the findings as positive, equivocal, or negative for clinically significant cancer. The radiologists then interpreted the mpMRI and assigned a PI-RADS score. A third independent reader retrospectively categorized the DWI-only exams without access to the mpMRI. The interpretations of DWI-only were compared to the PI-RADS classification from mpMRI and the histopathology from the biopsies. Non-biopsied patients were followed in a safety net monitoring for 56 months.

Results

Based on DWI-only, 29 (22.5%) of the exams were categorized as negative, 38 (29.5%) as equivocal and 62 (48.1%) as positive. Of the 56 patients with PI-RADS 4-5 at mpMRI, 55 were also categorized as positive at DWI-only. All patients diagnosed with clinically significant cancer were identified using DWI-only. 56 months of safety net monitoring did not reveal any clinically significant cancers among patients with exams categorized as negative or equivocal. There was high inter-reader agreement on positive findings, but less agreement on negative and equivocal findings.

Conclusions

In this concept study, the monoparametric DWI-only identified all patients with clinically significant cancer in a mpMRI-directed diagnostic pathway.

Total Prostate Specific Antigen in Prostate Cancer Screening in Hyperglycemic Individuals

AIM

In this study, it was aimed to investigate the reliability of total prostate-specific antigen (t-PSA) in prostate cancer screening in hyperglycemic (≥126 mg/dL) individuals.

METHODS

This research was planned as a cross-sectional retrospective study. Three hundred eleven cases which underwent biopsy with the suspicion of prostate cancer in the hospital were included in the study. Prostate cancer risk groups were categorized as low, intermediate and high. Those with fasting blood glucose (FBG) levels lower than 126 mg/dL were considered as the normoglycemia group.

RESULTS

It was determined that the t-PSA measurement was higher in the patient group with cancer (P < .001). It was determined that the median t-PSA levels of the intermediate and high cancer groups were higher than the low cancer group (P < .001 and P = .001, respectively). t-PSA was found to be associated with increased cancer risk in cases with FBG <126. However, an increase in t-PSA values in cases with FBG ≥126 was not associated with increased prostate cancer. There is no relationship between FBG measurement and t-PSA measurement (rs=0.05, P = .446). In addition, it was determined that the t-PSA measurements of patients with FBG ≥126 and FBG<126 did not differ (P = .962).

CONCLUSIONS

As a contribution to literature, we found that the t-PSA test lost its sensitivity in cases with plasma glucose levels above normal. Loss of sensitivity may result in underdiagnosis in prostate cancer and this, in turn, results in diagnosis of the cancer at a later stage. In the future, it may be necessary to adopt a different approach in prostate cancer screening in hyperglycemic cases.

Emerging MR methods for improved diagnosis of prostate cancer by multiparametric MRI

Current challenges of using serum prostate-specific antigen (PSA) level-based screening, such as the increased false positive rate, inability to detect clinically significant prostate cancer (PCa) with random biopsy, multifocality in PCa, and the molecular heterogeneity of PCa, can be addressed by integrating advanced multiparametric MR imaging (mpMRI) approaches into the diagnostic workup of PCa. The standard method for diagnosing PCa is a transrectal ultrasonography (TRUS)-guided systematic prostate biopsy, but it suffers from sampling errors and frequently fails to detect clinically significant PCa. mpMRI not only increases the detection of clinically significant PCa, but it also helps to reduce unnecessary biopsies because of its high negative predictive value. Furthermore, non-Cartesian image acquisition and compressed sensing have resulted in faster MR acquisition with improved signal-to-noise ratio, which can be used in quantitative MRI methods such as dynamic contrast-enhanced (DCE)-MRI. With the growing emphasis on the role of pre-biopsy mpMRI in the evaluation of PCa, there is an increased demand for innovative MRI methods that can improve PCa grading, detect clinically significant PCa, and biopsy guidance. To meet these demands, in addition to routine T1-weighted, T2-weighted, DCE-MRI, diffusion MRI, and MR spectroscopy, several new MR methods such as restriction spectrum imaging, vascular, extracellular, and restricted diffusion for cytometry in tumors (VERDICT) method, hybrid multi-dimensional MRI, luminal water imaging, and MR fingerprinting have been developed for a better characterization of the disease. Further, with the increasing interest in combining MR data with clinical and genomic data, there is a growing interest in utilizing radiomics and radiogenomics approaches. These big data can also be utilized in the development of computer-aided diagnostic tools, including automatic segmentation and the detection of clinically significant PCa using machine learning methods.

Machine Learning-Based Models Enhance the Prediction of Prostate Cancer

Purpose

PSA is currently the most commonly used screening indicator for prostate cancer. However, it has limited specificity for the diagnosis of prostate cancer. We aim to construct machine learning-based models and enhance the prediction of prostate cancer.

Methods

The data of 551 patients who underwent prostate biopsy were retrospectively retrieved and divided into training and test datasets in a 3:1 ratio. We constructed five PCa prediction models with four supervised machine learning algorithms, including tPSA univariate logistic regression (LR), multivariate LR, decision tree (DT), random forest (RF), and support vector machine (SVM). The five prediction models were compared based on model performance metrics, such as the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, calibration curve, and clinical decision curve analysis (DCA).

Results

All five models had good calibration in the training dataset. In the training dataset, the RF, DT, and multivariate LR models showed better discrimination, with AUCs of 1.0, 0.922 and 0.91, respectively, than the tPSA univariate LR and SVM models. In the test dataset, the multivariate LR model exhibited the best discrimination (AUC=0.918). The multivariate LR model and SVM model had better extrapolation and generalizability, with little change in performance between the training and test datasets. Compared with the DCA curves of the tPSA LR model, the other four models exhibited better net clinical benefits.

Conclusion

The results of the current retrospective study suggest that machine learning techniques can predict prostate cancer with significantly better AUC, accuracy, and net clinical benefits.

PSA density is complementary to prostate MP-MRI PI-RADS scoring system for risk stratification of clinically significant prostate cancer

BACKGROUND

While prostate multiparametric-magnetic resonance imaging (MP-MRI) has improved the diagnosis of clinically significant prostate cancer (CSPC), the complementary use of prostate-specific antigen (PSA) levels to risk-stratify for CSPC requires further study. The objective of this project was to determine if prostate MP-MRI and PSA can provide complementary insights into CSPC risk stratification.

METHODS

In an IRB-approved study, pathologic outcomes from patients who underwent MR/US fusion-targeted prostate biopsy were stratified by various parameters including PSA, PSA density (PSAD), age, race, and PI-RADS v2 score. CSPC was defined as a Gleason score ≥7. Logistic regression was used to determine odds ratios (OR) with 95% confidence intervals (CI). P values were reported as two-sided with p < 0.05 considered statistically significant. ROC curves were generated for assessing the predictive value of tests and sensitivity + specificity optimization was performed to determine optimal testing cutoffs.

RESULTS

A total of 327 patients with 709 lesions total were analyzed. PSAD and PI-RADS scores provided complementary predictive value for diagnosis of CSPC (AUC PSAD: 0.67, PI-RADS: 0.72, combined: 0.78, p < 0.001). When controlling for PI-RADS score, age, and race, multivariate analysis showed that PSAD was independently associated with CSPC (OR 1.03 per 0.01 PSAD increase, 95% CI 1.02-105, p < 0.001). The optimal cutoff of PSAD ≥ 0.1 ng/ml/cc shows that a high versus low PSAD was roughly equivalent to an increase in 1 in PI-RADS score for the presence of CSPC (4% of PI-RADS ≤3 PSAD low, 6% of PI-RADS 3 PSAD high vs. 5% of PI-RADS 4 PSAD low, 22% of PI-RADS 4 PSAD high vs. 29% of PI-RADS 5 PSAD low, 46% of PI-RADS 5 PSAD high were found to have CSPC).

CONCLUSIONS

PSAD with a cutoff of 0.1 ng/ml/cc appears to be a useful marker that can stratify the risk of CSPC in a complementary manner to prostate MP-MRI.

Diagnostic Accuracy of Abbreviated Bi-Parametric MRI (a-bpMRI) for Prostate Cancer Detection and Screening: A Multi-Reader Study

(1) Background: There is currently limited evidence on the diagnostic accuracy of abbreviated biparametric MRI (a-bpMRI) protocols for prostate cancer (PCa) detection and screening. In the present study, we aim to investigate the performance of a-bpMRI among multiple readers and its potential application to an imaging-based screening setting. (2) Methods: A total of 151 men who underwent 3T multiparametric MRI (mpMRI) of the prostate and transperineal template prostate mapping biopsies were retrospectively selected. Corresponding bpMRI (multiplanar T2WI, DWI, ADC maps) and a-bpMRI (axial T2WI and b 2000 s/mm² DWI only) dataset were derived from mpMRI. Three experienced radiologists scored a-bpMRI, standard biparametric MRI (bpMRI) and mpMRI in separate sessions. Diagnostic accuracy and interreader agreement of a-bpMRI was tested for different positivity thresholds and compared to bpMRI and mpMRI. Predictive values of a-bpMRI were computed for lower levels of PCa prevalence to simulate a screening setting. The primary definition of clinically significant PCa (csPCa) was Gleason ≥ 4 + 3, or cancer core length ≥ 6 mm. (3) Results: The median age was 62 years, the median PSA was 6.8 ng/mL, and the csPCa prevalence was 40%. Using a cut off of MRI score ≥ 3, the sensitivity and specificity of a-bpMRI were 92% and 48%, respectively. There was no significant difference in sensitivity compared to bpMRI and mpMRI. Interreader agreement of a-bpMRI was moderate (AC1 0.58). For a low prevalence of csPCa (e.g., <10%), higher cut offs (MRI score ≥ 4) yield a more favourable balance between the predictive values and positivity rate of MRI. (4) Conclusion: Abbreviated bpMRI protocols could match the diagnostic accuracy of bpMRI and mpMRI for the detection of csPCa. If a-bpMRI is used in low-prevalence settings, higher cut-offs for MRI positivity should be prioritised.

Prospective study of diagnostic accuracy in the detection of high-grade prostate cancer in biopsy-naïve patients with clinical suspicion of prostate cancer who underwent the Select MDx test

OBJECTIVES

This study aimed to externally validate the diagnostic accuracy of the Select MDx test for Significant prostate cancer (Sig PCa) (ISUP > 1), in a contemporaneous, prospective, multicenter cohort with a prostate-specific antigen (PSA) between 3 and 10 ng/ml and a non-suspicious digital rectal examination.

METHODS AND PARTICIPANTS

For all enrolled patients, the Select Mdx test, the risk calculator ERSPC3 + DRE, and a prostatic magnetic resonance imaging (MRI) were carried out. Subsequently, a systematic 12-core trans-rectal biopsy and a targeted biopsy, in the case of a prostate imaging-reporting and data system (PIRADS) > 2 lesion (max three lesions), were performed. To assess the accuracy of the Select MDx test in the detection of clinically Sig PCa, the test sensitivity was evaluated. Secondary objectives were specificity, negative predictive value (NPV), positive predictive value (PPV), and area under the curve (AUC). A direct comparison with the ERSPC + DRE risk calculator and MRI were also performed. We also studied the predictive ability to diagnose Sig PCa from the combination of the Select MDx test with MRI using clinical decision-curve analysis.

RESULTS

There were 163 patients enrolled after meeting the inclusion criteria and study protocol. The Select MDx test showed a sensitivity of 76.9% (95% CI, 63.2-87.5), 49.6% specificity (95% CI, 39.9-59.2), 82.09% (95% CI, 70.8-90.4) NPV, and 41.67% (95% CI, 31.7-52.2) PPV for the diagnosis of Sig PCa. COR analysis was also performed, which showed an AUC of 0.63 (95% CI, 0.56-0.71). There were no differences in the accuracy of Select MDx, ERSPC + DRE, or MRI. The combination of Select MDX + MRI showed the highest impact in the decision-curve analysis, with an NPV of 93%.

CONCLUSION

Our study showed a worse performance for the SelectMdx test than previously reported, within a cohort of patients with a PSA 3-10 ng/ml and a normal DRE, with results similar to those from ERSPC + DRE RC and MRI, but with an improvement in the usual PSA pathway. A combination of the Select Mdx test and MRI could improve accuracy, but studies specifically evaluating this scenario with a cost-effective analysis are needed.

Upregulated PPARG2 facilitates interaction with demethylated AKAP12 gene promoter and suppresses proliferation in prostate cancer

Prostate cancer (PCA) is one of the most common male genitourinary tumors. However, the molecular mechanisms involved in the occurrence and progression of PCA have not been fully clarified. The present study aimed to investigate the biological function and molecular mechanism of the nuclear receptor peroxisome proliferator-activated receptor gamma 2 (PPARG2) in PCA. Our results revealed that PPARG2 was downregulated in PCA, and overexpression of PPARG2 inhibited cell migration, colony formation, invasion and induced cell cycle arrest of PCA cells in vitro. In addition, PPARG2 overexpression modulated the activation of the Akt signaling pathway, as well as inhibited tumor growth in vivo. Moreover, mechanistic analysis revealed that PPARG2 overexpression induced increased expression level of miR-200b-3p, which targeted 3′ UTR of the downstream targets DNMT3A/3B, and facilitated interaction with demethylated AKAP12 gene promoter and suppressed cell proliferation in PCA. Our findings provided the first evidence for a novel PPARG2-AKAP12 axis mediated epigenetic regulatory network. The study identified a molecular mechanism involving an epigenetic modification that could be possibly targeted as an antitumoral strategy against prostate cancer.

Population-Based Prostate Cancer Screening With Magnetic Resonance Imaging or Ultrasonography: The IP1-PROSTAGRAM Study

Question

In men invited to undergo screening for prostate cancer with magnetic resonance imaging (MRI), ultrasonography, and prostate-specific antigen testing, what is the prevalence of positive test results, rates of biopsy, and detection of prostate cancer?

Findings

In this cohort study in which 408 men underwent 3 screening tests, an MRI score of 4 or 5 was associated with improved detection of clinically significant prostate cancer without an increase in the number of men who underwent biopsy or were overdiagnosed with clinically insignificant prostate cancer if prostate-specific antigen testing alone was used. Ultrasonography was not associated with improved screening performance.

Meaning

These findings suggest that a short, noncontrast MRI may have favorable performance characteristics as a community-based screening test.

Importance

Screening for prostate cancer using prostate-specific antigen (PSA) testing can lead to problems of underdiagnosis and overdiagnosis. Short, noncontrast magnetic resonance imaging (MRI) or transrectal ultrasonography might overcome these limitations.

Objective

To compare the performance of PSA testing, MRI, and ultrasonography as screening tests for prostate cancer.

Design, Setting, and Participants

This prospective, population-based, blinded cohort study was conducted at 7 primary care practices and 2 imaging centers in the United Kingdom. Men 50 to 69 years of age were invited for prostate cancer screening from October 10, 2018, to May 15, 2019.

Interventions

All participants underwent screening with a PSA test, MRI (T2 weighted and diffusion), and ultrasonography (B-mode and shear wave elastography). The tests were independently interpreted without knowledge of other results. Both imaging tests were reported on a validated 5-point scale of suspicion. If any test result was positive, a systematic 12-core biopsy was performed. Additional image fusion–targeted biopsies were performed if the MRI or ultrasonography results were positive.

Main Outcomes and Measures

The main outcome was the proportion of men with positive MRI or ultrasonography (defined as a score of 3-5 or 4-5) or PSA test (defined as PSA ≥3 μg/L) results. Key secondary outcomes were the number of clinically significant and clinically insignificant cancers detected if each test was used exclusively. Clinically significant cancer was defined as any Gleason score of 3+4 or higher.

Results

A total of 2034 men were invited to participate; of 411 who attended screening, 408 consented to receive all screening tests. The proportion with positive MRI results (score, 3-5) was higher than the proportion with positive PSA test results (72 [17.7%; 95% CI, 14.3%-21.8%] vs 40 [9.9%; 95% CI, 7.3%-13.2%]; P < .001). The proportion with positive ultrasonography results (score, 3-5) was also higher than the proportion of those with positive PSA test results (96 [23.7%; 95% CI, 19.8%-28.1%]; P < .001). For an imaging threshold of score 4 to 5, the proportion with positive MRI results was similar to the proportion with positive PSA test results (43 [10.6%; 95% CI, 7.9%-14.0%]; P = .71), as was the proportion with positive ultrasonography results (52 [12.8%; 95% CI, 9.9%-16.5%]; P = .15). The PSA test (≥3 ng/mL) detected 7 clinically significant cancers, an MRI score of 3 to 5 detected 14 cancers, an MRI score of 4 to 5 detected 11 cancers, an ultrasonography score of 3 to 5 detected 9 cancer, and an ultrasonography score of 4 to 5 detected 4 cancers. Clinically insignificant cancers were diagnosed by PSA testing in 6 cases, by an MRI score of 3 to 5 in 7 cases, an MRI score of 4 to 5 in 5 cases, an ultrasonography score of 3 to 5 in 13 cases, and an ultrasonography score of 4 to 5 in 7 cases.

Conclusions and Relevance

In this cohort study, when screening the general population for prostate cancer, MRI using a score of 4 or 5 to define a positive test result compared with PSA alone at 3 ng/mL or higher was associated with more men diagnosed with clinically significant cancer, without an increase in the number of men advised to undergo biopsy or overdiagnosed with clinically insignificant cancer. There was no evidence that ultrasonography would have better performance compared with PSA testing alone.