Image-guided prostate biopsy using magnetic resonance imaging-derived targets: a systematic review

Interaction of patient age and high-grade prostate cancer on targeted biopsies of MRI suspicious lesions

OBJECTIVES

To evaluate the interaction of patient age and Prostate Imaging-Reporting and Data System (PI-RADS) score in determining the grade of prostate cancer (PCa) identified on magnetic resonance imaging (MRI)-targeted biopsy in older men.

PATIENTS AND METHODS

From a prospectively accrued Institutional Review Board-approved comparative study of MRI-targeted and systematic biopsy between June 2012 and December 2022, men with at least one PI-RADS ≥3 lesion on pre-biopsy MRI and no prior history of PCa were selected. Ordinal and binomial logistic regression analyses were performed.

RESULTS

A total of 2677 men met study criteria. The highest PI-RADS score was 3 in 1220 men (46%), 4 in 950 men (36%), and 5 in 507 men (19%). The median (interquartile range [IQR]) patient age was 66.7 (60.8-71.8) years, median (IQR) prostate-specific antigen (PSA) level was 6.1 (4.6-9.0) ng/mL, median (IQR) prostate volume was 48 (34-68) mL, and median (IQR) PSA density was 0.13 (0.08-0.20) ng/mL/mL. Clinically significant (cs)PCa and high-risk PCa were identified on targeted biopsy in 1264 (47%) and 321 (12%) men, respectively. Prevalence of csPCa and high-risk PCa were significantly higher in the older age groups. On multivariable analyses, patient age was significantly associated with csPCa but not high-risk PCa; PI-RADS score and the interaction of age and PI-RADS score were significantly associated with high-risk PCa but not csPCa.

CONCLUSION

In our cohort, the substantial rate of high-risk PCa on MRI-ultrasound fusion targeted biopsies in older men, and its significant association with MRI findings, supports the value of pre-biopsy MRI to localise disease that could cause cancer mortality even in older men.

Established and emerging liquid biomarkers for prostate cancer detection: A review

Prostate cancer remains one of the most frequently diagnosed cancers among men in the world today. Since its introduction in 1987 and FDA approval in 1994, prostate specific antigen (PSA) has reduced prostate cancer specific mortality considerably. However, the positive and negative predictive value of PSA is less than ideal and can lead to the over-detection of clinically insignificant prostate cancer. In the search for better screening measures to identify this cohort, liquid biomarkers for prostate cancer have emerged. In this review we will explore the commonly used urine and blood based prostate cancer liquid biomarkers. We detail the mechanism of each test and the validation studies that underscore their efficacy. Additionally, we will examine each test's effect on shared decision making as well as their cost efficacy in clinical practice.

Significant prostate cancer risk after MRI-guided biopsy showing benign findings: Results from a cohort of 381 men

BACKGROUND

MRI-guided biopsy (MGB) contributes to the diagnosis of clinically significant Prostate Cancer (csPCa). However, there are no clear recommendations for the management of men after a negative MGB. The aim of this study was to assess the risk of csPCa after a first negative MGB.

METHODS

Between 2014 and 2020, we selected men with a PI-RADS score ≥ 3 on MRI and a negative MGB (showing benign findings) performed for suspected prostate cancer. MGB (targeted and systematic biopsies) was performed using fully integrated mobile fusion imaging (KOELIS). The primary endpoint was the rate of csPCa (defined as an ISUP grade ≥ 2) diagnosed after a first negative MGB.

RESULTS

A total of 381 men with a negative MGB and a median age of 65 (IQR: 59-69, range: 46-85) years were included. During the median follow-up of 31 months, 124 men (32.5%) had a new MRI, and 76 (19.9%) were referred for a new MGB, which revealed csPCa in 16 (4.2%) of them. We found no statistical difference in the characteristics of men diagnosed with csPCa compared with men with no csPCa after the second MGB.

CONCLUSION

We observed a risk of significant prostate cancer in 4% of men two years after a negative MRI-guided biopsy. Performing a repeat MRI could improve the selection of men who will benefit from a repeat MRI-guided biopsy, but a clear protocol is needed to follow these patients.

LEVEL OF EVIDENCE: 4

Detection of anterior prostate cancer using a magnetic resonance imaging-transrectal ultrasound fusion biopsy in cases with initial biopsy and history of systematic biopsies

Background

Prostate cancer in the anterior region may be missed on a transrectal systematic biopsy (SBx). Therefore, this study aimed to evaluate the performance of magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion targeted biopsy (TBx) in detecting anterior region cancer in patients with a history of SBxs.

Methods

Prostate biopsies were performed in 224 patients after multiparametric MRI, among whom 119 patients with prostate imaging reporting and data system (PI-RADS version 2) scores of 3 to 5 underwent MRI-TRUS fusion TBxs. Afterward, cancer detection rates (CDRs) and TBx-positive core regions were compared by categorizing patients into those with or without a history of SBxs.

Results

Total CDR was 68.8% (44/64 cases) in the initial biopsy group (Initial-Bx group) and 47.3% (26/55 cases) in the previous-negative-systematic biopsy group (Pre-Neg-SBx group) (P = 0.018). Interestingly, both TBx- and SBx-core positive cases were more common in the Initial-Bx group than in the Pre-Neg-SBx group (Initial-Bx group: 75% [33/44 cases] vs. Pre-Neg-SBx group: 42.3% [11/26 cases], P = 0.006). However, only TBx-core positive cases were more common in the Pre-Neg-SBx group than in the Initial-Bx group (Initial-Bx group: 11.4% [5/44 cases] vs. Pre-Neg-SBx group: 30.8% [8/26 cases], P = 0.043). In addition, the proportion of anterior lesions detected by TBx cores was higher in the Pre-Neg-SBx group than in the Initial-Bx group (Initial-Bx group: 26.3% [10/38 cases] vs. Pre-Neg-SBx group: 52.6% [10/19 cases], P = 0.049).

Conclusion

Using MRI-TRUS fusion TBx in the evaluation of previously negative SBx cases improved the detection rate of anterior lesions, which might have been missed in previous SBxs. Especially in patients with a history of SBxs mpMRI should be performed to screen for anterior lesions.

Comparing 12-core and 20-core biopsy for prostate cancer diagnosis with transperineal MR/US fusion biopsy: assessing the effective number of systemic cores using propensity score matching

PURPOSE

For transperineal (TP) prostate biopsy, target biopsy for visible lesions on MRI is important, but there is no consensus of the number of systemic biopsy cores. Our study aimed to confirm the diagnostic efficiency of 20-core systemic biopsy by comparison with 12-core using propensity score matching (PSM).

METHODS

The 494 patients conducted the naive TP biopsy were retrospectively analyzed. There were 293 patients with 12-core biopsy and 201 patients with 20-core biopsy. PSM was performed for minimizing confounding variables, and the established effects' value was analyzed for 'index-positive or negative' clinically significant prostate cancer (csPCa) (Index means PIRADS Score ≥ 3 on multiparametric prostate MRI).

RESULTS

At 12-core biopsy, there were 126 cases of prostate cancer (43.0%), and 97 cases of csPCa (33.1%). At 20-core biopsy, there were 91 cases (45.3%) and 63 cases (31.3%). After propensity score matching, for index-negative csPCa, the estimated odds ratio was 4.03 (95% CI 1.35-12.09, p value 0.0128), and for index-positive csPCa, the estimated odds ratio was 0.98 (95% CI 0.63-1.52, p value 0.9308).

CONCLUSIONS

The 20-core biopsy did not show a higher detection rate for csPCa in comparison with the 12-core biopsy. However, when MRI did not show a suspicious lesion, 20-core biopsy showed higher odd ratio in comparison with 12-core biopsy. Therefore, if there is a suspicious lesion in MRI, 20-core biopsy is excessive and 12-core biopsy is sufficient. Whereas if there is no suspicious lesion in MRI, it is better to proceed with 20-core biopsy.

ACR Appropriateness Criteria® Pretreatment Detection, Surveillance, and Staging of Prostate Cancer: 2022 Update

Prostate cancer is second leading cause of death from malignancy after lung cancer in American men. The primary goal during pretreatment evaluation of prostate cancer is disease detection, localization, establishing disease extent (both local and distant), and evaluating aggressiveness, which are the driving factors of patient outcomes such as recurrence and survival. Prostate cancer is typically diagnosed after the recognizing elevated serum prostate-specific antigen level or abnormal digital rectal examination. Tissue diagnosis is obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy, commonly with multiparametric MRI without or with intravenous contrast, which has recently been established as standard of care for detecting, localizing, and assessing local extent of prostate cancer. Although bone scintigraphy and CT are still typically used to detect bone and nodal metastases in patients with intermediate- or high-risk prostate cancer, novel advanced imaging modalities including prostatespecific membrane antigen PET/CT and whole-body MRI are being more frequently utilized for this purpose with improved detection rates. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Assessment of prostate cancer progression using a translational needle photoacoustic sensing probe: Preliminary study with intact human prostates ex-vivo

In our previous studies, we demonstrated the ability of an interstitial all-optical needle photoacoustic (PA) sensing probe and PA spectral analysis (PASA) to assess the aggressiveness of prostate cancer. In this clinical translation investigation, we integrated the optical components of the needle PA sensing probe into a 18G steel needle. The translational needle PA sensing probe was evaluated using intact human prostates in a simulated ultrasound-guided transperineal prostate biopsy. PA signals were acquired at 1220 nm, 1370 nm, 800 nm and 266 nm at each interstitial measurement location and quantified by PASA within the frequency range of 8-28 MHz. The measurement locations were stained for establishing spatial correlations between the quantitative measurements and the histological diagnosing. Most of the quantitative PA assessments reveal statistically significant differences between the benign and cancerous regions. Multivariate analysis combining the PASA quantifications shows an accuracy close to 90% in differentiating the benign and cancerous regions in the prostates.

Role of MRI in diagnosis of prostate cancer and correlation of results with transrectal ultrasound guided biopsy “TRUS”

Background

Prostate cancer is the most common cancer in elderly men, and the second leading cause of cancer-related death in developed countries. For a long time, TRUS is used in screening, diagnosis of prostate lesions. Recently the implementation of multi parametric MRI into a screening program currently seems to be the most promising technique to improve the early detection of prostate cancer.

Results

Thirty Patients were referred from urological outpatient clinics complaining of urological symptoms (dysuria, frequency and urine retention). The study was carried, and the patients were submitted to Ultrasonography, conventional magnetic resonance, diffusion weighted images and MR spectroscopy techniques, these results were correlated with histopathological data. In this study Conventional MRI has moderate sensitivity 81.8% and low specificity 37.3% in diagnosing prostate malignancy. Using of mpMRI combination of diffusion-weighted, Dynamic contrast enhanced and MR spectroscopic imaging is a promising approach for discriminating between benign and malignant lesions in the PZ and increase sensitivity 100% and specificity 96.6% in diagnosing prostate malignancy.

Conclusions

The standard for the definitive diagnosis of prostate cancer is trans-rectal ultrasound biopsy. However, TRUS guided biopsy has a significant sampling error and can miss up to 30% of cancers and may show underestimation of Gleason grade, especially in anteriorly located tumors. It may lead to an increase in complications. MRI has an essential role to play in making safer in diagnosis. It can aid in staging also and surgery or radiation treatment planning. Although T2W MRI has been used widely for diagnosis on the basis of its excellent soft tissue resolution, but its accuracy for the detection and localization of cancer prostate is unsatisfactory. The implementation of multi parametric MRI: MR spectroscopy, Dynamic contrast enhanced and diffusion weighted imaging into a diagnosis program improve the diagnostic performance. These advances are beginning to translate into better treatment selection and more accurate image-guided therapies. In addition, early detection of local recurrence.

Combining prostate-specific antigen density with prostate imaging reporting and data system score version 2.1 to improve detection of clinically significant prostate cancer: A retrospective study

Globally, Prostate cancer (PCa) is the second most common cancer in the male population worldwide, but clinically significant prostate cancer (CSPCa) is more aggressive and causes to more deaths. The authors aimed to construct the risk category based on Prostate Imaging Reporting and Data System score version 2.1 (PI-RADS v2.1) in combination with Prostate-Specific Antigen Density (PSAD) to improve CSPCa detection and avoid unnecessary biopsy. Univariate and multivariate logistic regression and receiver-operating characteristic (ROC) curves were performed to compare the efficacy of the different predictors. The results revealed that PI-RADS v2.1 score and PSAD were independent predictors for CSPCa. Moreover, the combined factor shows a significantly higher predictive value than each single variable for the diagnosis of CSPCa. According to the risk stratification model constructed based on PI-RADS v2.1 score and PSAD, patients with PI-RADS v2.1 score of ≤2, or PI-RADS V2.1 score of 3 and PSA density of <0.15 ng/mL2, can avoid unnecessary of prostate biopsy and does not miss clinically significant prostate cancer.

Interventional oncology update

Interventional Oncology (IO) is a subspecialty field of Interventional Radiology bridging between diagnostic radiology and the clinical oncology team, addressing the diagnosis and treatment of cancer. There have been many exciting advancements in the field of IO in recent years; far too many to cover in a single paper. To give each topic sufficient attention, we have limited the scope of this review article to four topics which we feel have the potential to drastically change how cancer is treated managed in the immediate future.

Intratumorally anchored cytokine therapy

INTRODUCTION

On-target, off-tumor toxicity severely limits systemic dosing of cytokines and agonist antibodies for cancer. Intratumoral administration is increasingly being explored to mitigate this problem. Full exploitation of this mode of administration must include a mechanism for sustained retention of the drug; otherwise, rapid diffusion out of the tumor eliminates any advantage.

AREAS COVERED

We focus here on strategies for anchoring immune agonists in accessible formats. Such anchoring may utilize extracellular matrix components, cell surface receptor targets, or exogenously administered particulate materials. Promising alternative strategies not reviewed here include slow release from the interior of a material depot, expression following local transfection, and conditional proteolytic activation of masked molecules.

EXPERT OPINION

An effective mechanism for tissue retention is a critical component of intratumorally anchored cytokine therapy, as leakage leads to decreased tumor drug exposure and increased systemic toxicity. Matching variable drug release kinetics with receptor-mediated cellular uptake is an intrinsic requirement for the alternative strategies mentioned above. Bioavailability of an anchored form of the administered drug is key to obviating this balancing act.

Clinical Applications of Liquid Biopsy in Prostate Cancer: From Screening to Predictive Biomarker

Prostate cancer (PC) remains the most common malignancy and the second most common cause of cancer death in men. As a result of highly variable biological behavior and development of resistance to available agents under therapeutic pressure, optimal management is often unclear. Traditional surgical biopsies, even when augmented by genomic studies, may fail to provide adequate guidance for clinical decisions as these can only provide a snapshot of a dynamic process. Additionally, surgical biopsies are cumbersome to perform repeatedly and often involve risk. Liquid biopsies (LB) are defined as the analysis of either corpuscular (circulating tumor cells, extracellular vesicles) or molecular (circulating DNA or RNA) tumor-derived material. LB could more precisely identify clinically relevant alterations that characterize the metastatic potential of tumors, predict response to specific treatments or actively monitor for the emergence of resistance. These tests can potentially be repeated as often as deemed necessary and can detect real-time response to treatment with minimal inconvenience to the patient. In the current review, we consider common clinical scenarios to describe available LB assays in PC as a platform to explore existing evidence for their use in guiding decision making and to discuss current limitations to their adoption in the clinic.

Quick identification of prostate cancer by wavelet transform-based photoacoustic power spectrum analysis

Pathology is currently the gold standard for grading prostate cancer (PCa). However, pathology takes considerable time to provide a final result and is significantly dependent on subjective judgment. In this study, wavelet transform-based photoacoustic power spectrum analysis (WT-PASA) was used for grading PCa with different Gleason scores (GSs). The tumor region was accurately identified via wavelet transform time-frequency analysis. Then, a linear fitting was conducted on the photoacoustic power spectrum curve of the tumor region to obtain the quantified spectral parameter slope. The results showed that high GSs have small glandular cavity structures and higher heterogeneity, and consequently, the slopes at both 1210 nm and 1310 nm were high (p < 0.01). The classification accuracy of the PA time frequency spectrum (PA-TFS) of tumor region using ResNet-18 was 89% at 1210 nm and 92.7% at 1310 nm. Further, the testing time was less than 7 mins. The results demonstrated that identification of PCa can be rapidly and objectively realized using WT-PASA.

Prostate Cancer Gleason Score From Biopsy to Radical Surgery: Can Ultrasound Shear Wave Elastography and Multiparametric Magnetic Resonance Imaging Narrow the Gap?

Objectives

To investigate the impact of ultrasound shear wave elastography (USWE) and multiparametric magnetic resonance imaging (mpMRI) in predicting a change in biopsy-assigned Gleason Score (GS) after radical surgery for localised prostate cancer (PCa).

Method

A total of 212 men opting for laparoscopic radical prostatectomy (LRP) between September 2013 and June 2017 were recruited into this study. All the participants had 12-core transrectal ultrasound (TRUS) biopsies and imaging using USWE and mpMRI before radical surgery. The predictive accuracy for imaging modalities was assessed in relation to upgrading and downgrading of PCa GS between the biopsies and radical prostatectomy using Student's t-test and multivariable logistic regression analyses. A decision analysis curve was constructed assessing the impact of nomogram on clinical situations using different thresholds of upgrading probabilities.

Results

Most GS 6 diseases on biopsies were upgraded on radical surgery (37/42, 88.1%). Major downgrading was seen in GS 8 category of disease (14/35; 37.1%), whereas no alteration was observed in GS 7 on biopsies in most men (55/75; 73.3%). In univariate analysis, higher preoperative prostate-specific antigen (PSA) (p = 0.001), higher prostate-specific antigen density (PSAD) (p = 0.002), stiffer USWE lesions (p = 0.009), and higher prostate imaging-reporting and data system (PIRADS) (p = 0.002) on mpMRI were significant predictors of upgrading. In multivariate logistic regression analyses, only PSA (p = 0.016) and USWE-measured tissue stiffness (p = 0.029) showed statistical significance in predicting upgrading.

Conclusions

Measurement of tissue stiffness using USWE in clinically localised PCa can predict upgrading of GS and has the potential to improve patient management options.

Real-time multimodal image registration with partial intraoperative point-set data

We present Free Point Transformer (FPT) - a deep neural network architecture for non-rigid point-set registration. Consisting of two modules, a global feature extraction module and a point transformation module, FPT does not assume explicit constraints based on point vicinity, thereby overcoming a common requirement of previous learning-based point-set registration methods. FPT is designed to accept unordered and unstructured point-sets with a variable number of points and uses a "model-free" approach without heuristic constraints. Training FPT is flexible and involves minimizing an intuitive unsupervised loss function, but supervised, semi-supervised, and partially- or weakly-supervised training are also supported. This flexibility makes FPT amenable to multimodal image registration problems where the ground-truth deformations are difficult or impossible to measure. In this paper, we demonstrate the application of FPT to non-rigid registration of prostate magnetic resonance (MR) imaging and sparsely-sampled transrectal ultrasound (TRUS) images. The registration errors were 4.71 mm and 4.81 mm for complete TRUS imaging and sparsely-sampled TRUS imaging, respectively. The results indicate superior accuracy to the alternative rigid and non-rigid registration algorithms tested and substantially lower computation time. The rapid inference possible with FPT makes it particularly suitable for applications where real-time registration is beneficial.

Racial and Ethnic Disparities in the Use of Prostate Magnetic Resonance Imaging Following an Elevated Prostate-Specific Antigen Test

IMPORTANCE

Prostate cancer screening and diagnosis exhibit known racial and ethnic disparities. Whether these disparities persist in prostate magnetic resonance imaging (MRI) utilization after elevated prostate-specific antigen (PSA) results is poorly understood.

OBJECTIVE

To assess potential racial and ethnic disparities in prostate MRI utilization following elevated PSA results.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study of 794 809 insured US men was drawn from deidentified medical claims between January 2011 and December 2017 obtained from a commercial claims database. Eligible participants were aged 40 years and older and received a single PSA result and no prior PSA screening or prostate MRI claims. Analysis was performed in January 2021.

MAIN OUTCOMES AND MEASURES

Multivariable logistic regression was used to examine associations between elevated PSA results and follow-up prostate MRI. For patients receiving prostate MRI, multivariable regressions were estimated for the time between PSA and subsequent prostate MRI. PSA thresholds explored included PSA levels above 2.5 ng/mL, 4 ng/mL, and 10 ng/mL. Analyses were stratified by race, ethnicity, and age.

RESULTS

Of 794 809 participants, 51 500 (6.5%) had PSA levels above 4 ng/mL; of these, 1524 (3.0%) underwent prostate MRI within 180 days. In this sample, mean (SD) age was 59.8 (11.3) years (range 40-89 years); 31 350 (3.9%) were Asian, 75 935 (9.6%) were Black, 107 956 (13.6%) were Hispanic, and 455 214 (57.3%) were White. Compared with White patients, Black patients with PSA levels above 4 ng/mL and 10 ng/mL were 24.1% (odds ratio [OR], 0.78; 95% CI, 0.65-0.89) and 35.0% (OR, 0.65; 95% CI, 0.50-0.85) less likely to undergo subsequent prostate MRI, respectively. Asian patients with PSA levels higher than 4 ng/mL (OR, 0.76; 95% CI, 0.58-0.99) and Hispanic patients with PSA levels above 10 ng/mL (OR, 0.77; 95% CI, 0.59-0.99) were also less likely to undergo subsequent prostate MRI compared with White patients. Black patients between ages 65 and 74 years with PSA above 4 ng/mL and 10 ng/mL were 23.6% (OR, 0.76; 95% CI, 0.64-0.91) and 43.9% (OR, 0.56; 95% CI, 0.35-0.91) less likely to undergo MRI, respectively. Race and ethnicity were not significantly associated with mean time between PSA and MRI.

CONCLUSIONS AND RELEVANCE

Among men with elevated PSA results, racial and ethnic disparities were evident in subsequent prostate MRI utilization and were more pronounced at higher PSA thresholds. Further research is needed to better understand and mitigate physician decision-making biases and other potential sources of disparities in prostate cancer diagnosis and management.

Glioblastoma multiforme (GBM): An overview of current therapies and mechanisms of resistance

Glioblastoma multiforme (GBM) is a WHO grade IV glioma and the most common malignant, primary brain tumor with a 5-year survival of 7.2%. Its highly infiltrative nature, genetic heterogeneity, and protection by the blood brain barrier (BBB) have posed great treatment challenges. The standard treatment for GBMs is surgical resection followed by chemoradiotherapy. The robust DNA repair and self-renewing capabilities of glioblastoma cells and glioma initiating cells (GICs), respectively, promote resistance against all current treatment modalities. Thus, durable GBM management will require the invention of innovative treatment strategies. In this review, we will describe biological and molecular targets for GBM therapy, the current status of pharmacologic therapy, prominent mechanisms of resistance, and new treatment approaches. To date, medical imaging is primarily used to determine the location, size and macroscopic morphology of GBM before, during, and after therapy. In the future, molecular and cellular imaging approaches will more dynamically monitor the expression of molecular targets and/or immune responses in the tumor, thereby enabling more immediate adaptation of tumor-tailored, targeted therapies.

A review of the research progress of interventional medical equipment and methods for prostate cancer

BACKGROUND

Prostate cancer is a common disease in men and has a relatively high mortality rate. However, the interventional medical equipment used for prostate biopsy and brachytherapy has always been a social concern.

METHODS

To understand interventional medical equipment for prostate cancer, the structure of manual, semi-automatic and automatic medical equipment were considered as the mainline, while the corresponding research on these structures were the auxiliary lines. The characteristics and corresponding research status have been discussed.

RESULTS

Interventional medical equipment for prostate cancer with different degrees of automation and its characteristics were determined, and the imaging principles and characteristics of computed tomography, transrectal ultrasound and magnetic resonance imaging have been briefly described.

CONCLUSION

Certain feasible research suggestions have been proposed for future development from the perspective of structure, accuracy and safety. These include flexible and compact robot structures, high-precision image recognition and guidance, accurate dose planning and monitoring, real-time imaging monitoring without delay, high-precision needle insertion strategy, master-slave control, virtual reality and remote control.

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

Purpose

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

Methods and materials

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

Results

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

Conclusions

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

Supplementary Information

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

Extent of High-Grade Prostatic Adenocarcinoma in Multiparametric Magnetic Resonance Imaging-Targeted Biopsy Enhances Prediction of Pathologic Stage

CONTEXT.—

Multiparametric magnetic resonance imaging (mpMRI) of prostate with targeted biopsy has enhanced detection of high-grade prostatic adenocarcinoma (HG PCa). However, utility of amount of HG PCa (Gleason pattern 4/5) in mpMRI-targeted biopsies versus standard 12-core biopsies in predicting adverse outcomes on radical prostatectomy (RP) is unknown.

OBJECTIVE.—

To examine the utility of amount of HG PCa in mpMRI-targeted biopsies versus standard 12-core biopsies in predicting adverse RP outcomes.

DESIGN.—

We performed a retrospective review of prostate biopsies, which had corresponding RP, 1 or more mpMRI-targeted biopsy, and grade group 2 disease or higher. For the 169 cases identified, total millimeters of carcinoma and HG PCa, and longest length HG PCa in a single core were recorded for 12-core biopsies and each set of mpMRI-targeted biopsies. For RP specimens, Gleason grade, extraprostatic extension, seminal vesicle involvement, and lymph node metastasis were recorded. The main outcome studied was prostate-confined disease at RP. A logistic regression model was used to test which pre-RP variables related to this outcome.

RESULTS.—

Univariate analysis showed significant associations with adverse RP outcomes in 5 of 8 quantifiable variables; longest millimeter HG PCa in a single 12-core biopsy, highest grade group in any core, and total millimeter HG in mpMRI-targeted biopsies showed no statistical association (P = .54, P = .13, and P = .55, respectively). In multivariate analysis, total millimeter carcinoma in all cores, highest GrGrp in any core, and longest millimeter HG PCa in a single mpMRI-targeted core provided additional predictive value (P < .001, P = .004, and P = .03, respectively).

CONCLUSIONS.—

Quantitation of HG PCa in mpMRI-targeted biopsies provides additional value over 12-core biopsies alone in predicting nonorgan confined prostate cancer at RP. Linear millimeters of HG PCa in mpMRI-targeted biopsies is a significant parameter associated with higher pathologic stage and could be of value in risk models.

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

Objectives

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

Materials and methods

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

Results

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

Conclusions

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

Diagnostic yield of fusion magnetic resonance-guided prostate biopsy versus cognitive-guided biopsy in biopsy-naive patients: a head-to-head randomized controlled trial

BACKGROUND

The combination of MRI-guided targeted biopsy (MRGB) with systematic biopsy (SB) provides the highest accuracy in detecting prostate cancer. There is a controversy over the superiority of fusion targeted biopsy (fus-MRGB) over cognitive targeted biopsy (cog-MRGB). The present head-to-head randomized controlled trial was performed to compare diagnostic yield of fus-MRGB in combination with SB with cog-MRGB in combination with SB.

METHODS

Biopsy-naive patients with a prostate-specific antigen level between 2 and 10 ng/dL who were candidates for prostate biopsy were included in the study. Multiparametric MRI was performed on all patients and patients with suspicious lesions with Prostate Imaging Reporting and Data System score of 3 or more were randomized into two groups. In the cog-MRGB group, a targeted cognitive biopsy was performed followed by a 12-core SB. Similarly, in the fus-MRGB group, first targeted fusion biopsy and then SBs were performed. The overall and clinically significant prostate cancer detection rates between the two study groups were compared by the Pearson χ² test. McNemar test was used to compare detection rates yielded by SB and targeted biopsy in each study group.

RESULTS

One-hundred men in the cog-MRGB group and 99 men in the fus-MRGB group were compared. The baseline characteristics of patients including age, PSA level, prostate volume, PSA density, and clinical stage were similar in the two groups (p > 0.05). Both the overall and clinically significant prostate cancer detection rates in the fus-MRGB group (44.4% and 33.3%, respectively) were significantly higher than cog-MRGB group (31.0% and 19.0%, respectively) (p = 0.035 and p = 0.016, respectively).

CONCLUSION

The accuracy of identifying overall and clinically significant prostate cancer by fus-MRGB in biopsy-naive patients with PSA levels between 2 and 10 ng/dL is significantly higher than cog-MRGB and if available, we recommend using fus-MRGB over cog-MRGB in these patients.

Comparison of Multiparametric Magnetic Resonance Imaging-Targeted Biopsy With Systematic Transrectal Ultrasonography Biopsy for Biopsy-Naive Men at Risk for Prostate Cancer: A Phase 3 Randomized Clinical Trial

Importance

Magnetic resonance imaging (MRI) with targeted biopsy is an appealing alternative to systematic 12-core transrectal ultrasonography (TRUS) biopsy for prostate cancer diagnosis, but has yet to be widely adopted.

Objective

To determine whether MRI with only targeted biopsy was noninferior to systematic TRUS biopsies in the detection of International Society of Urological Pathology grade group (GG) 2 or greater prostate cancer.

Design, Setting, and Participants

This multicenter, prospective randomized clinical trial was conducted in 5 Canadian academic health sciences centers between January 2017 and November 2019, and data were analyzed between January and March 2020. Participants included biopsy-naive men with a clinical suspicion of prostate cancer who were advised to undergo a prostate biopsy. Clinical suspicion was defined as a 5% or greater chance of GG2 or greater prostate cancer using the Prostate Cancer Prevention Trial Risk Calculator, version 2. Additional criteria were serum prostate-specific antigen levels of 20 ng/mL or less (to convert to micrograms per liter, multiply by 1) and no contraindication to MRI.

Interventions

Magnetic resonance imaging-targeted biopsy (MRI-TB) only if a lesion with a Prostate Imaging Reporting and Data System (PI-RADS), v 2.0, score of 3 or greater was identified vs 12-core systematic TRUS biopsy.

Main Outcome and Measures

The proportion of men with a diagnosis of GG2 or greater cancer. Secondary outcomes included the proportion who received a diagnosis of GG1 prostate cancer; GG3 or greater cancer; no significant cancer but subsequent positive MRI results and/or GG2 or greater cancer detected on a repeated biopsy by 2 years; and adverse events.

Results

The intention-to-treat population comprised 453 patients (367 [81.0%] White, 19 [4.2%] African Canadian, 32 [7.1%] Asian, and 10 [2.2%] Hispanic) who were randomized to undergo TRUS biopsy (226 [49.9%]) or MRI-TB (227 [51.1%]), of which 421 (93.0%) were evaluable per protocol. A lesion with a PI-RADS score of 3 or greater was detected in 138 of 221 men (62.4%) who underwent MRI, with 26 (12.1%), 82 (38.1%), and 30 (14.0%) having maximum PI-RADS scores of 3, 4, and 5, respectively. Eighty-three of 221 men who underwent MRI-TB (37%) had a negative MRI result and avoided biopsy. Cancers GG2 and greater were identified in 67 of 225 men (30%) who underwent TRUS biopsy vs 79 of 227 (35%) allocated to MRI-TB (absolute difference, 5%, 97.5% 1-sided CI, -3.4% to ∞; noninferiority margin, -5%). Adverse events were less common in the MRI-TB arm. Grade group 1 cancer detection was reduced by more than half in the MRI arm (from 22% to 10%; risk difference, -11.6%; 95% CI, -18.2% to -4.9%).

Conclusions and Relevance

Magnetic resonance imaging followed by selected targeted biopsy is noninferior to initial systematic biopsy in men at risk for prostate cancer in detecting GG2 or greater cancers.

Trial Registration

ClinicalTrials.gov Identifier: NCT02936258.

For men enrolled in active surveillance, pre-biopsy biparametric magnetic resonance imaging significantly reduces the risk of reclassification and disease progression after 1 year

AIMS

To assess the level of disease progression at confirmatory staging biopsies after 1 year of active surveillance (AS) and compare the detection rate of significant prostate cancers (PCas) in patients who underwent pre-biopsy biparametric magnetic resonance imaging (bpMRI) before the first set of diagnostic transrectal ultrasonography-guided biopsies (TRUS-bx) with the detection rate in patients who did not undergo pre-biopsy bpMRI.

MATERIALS AND METHODS

Comparison of two patient groups enrolled in AS. Patients in Group A (n = 127) underwent pre-biopsy bpMRI followed by TRUS-bx ± targeted biopsies. Patients in Group B (n = 127) were enrolled in AS based on biopsy results from TRUS-bx only.

RESULTS

Overall, 6% of the patients in Group A and 20% of the patients in Group B had an upgrade in Gleason grade from insignificant to significant PCa at confirmatory staging biopsies (odds ratio [OR], 3.5; p = .002; 95% confidence interval [CI], 1.6-7.9).

CONCLUSIONS

Patients who underwent pre-biopsy bpMRI before the first set of diagnostic biopsies had a reduced risk of reclassification and disease progression after 1 year of AS. Thus, pre-biopsy bpMRI improves the selection of men who should be enrolled in AS.

Magnetic resonance imaging-guided prostate biopsy-A review of literature

Objective

Multiparametric magnetic resonance imaging (MP-MRI) helps to identify lesion of prostate with reasonable accuracy. We aim to describe the various uses of MP-MRI for prostate biopsy comparing different techniques of MP-MRI guided biopsy.

Materials and methods

A literature search was performed for "multiparametric MRI", "MRI fusion biopsy", "MRI guided biopsy", "prostate biopsy", "MRI cognitive biopsy", "MRI fusion biopsy systems", "prostate biopsy" and "cost analysis". The search operation was performed using the operator "OR" and "AND" with the above key words. All relevant systematic reviews, original articles, case series, and case reports were selected for this review.

Results

The sensitivity of MRI targeted biopsy (MRI-TB) is between 91%-93%, and the specificity is between 36%-41% in various studies. It also has a high negative predictive value (NPV) of 89%-92% and a positive predictive value (PPV) of 51%-52%. The yield of MRI fusion biopsy (MRI-FB) is similar, if not superior to MR cognitive biopsy. In-bore MRI-TB had better detection rates compared to MR cognitive biopsy, but were similar to MR fusion biopsy.

Conclusions

The use of MRI guidance in prostate biopsy is inevitable, subject to availability, cost, and experience. Any one of the three modalities (i.e. MRI cognitive, MRI fusion and MRI in-bore approach) can be used. MRI-FB has a fine balance with regards to accuracy, practicality and affordability.

Magnetic Resonance Imaging Based Radiomic Models of Prostate Cancer: A Narrative Review

Simple Summary

The increasing interest in implementing artificial intelligence in radiomic models has occurred alongside advancement in the tools used for computer-aided diagnosis. Such tools typically apply both statistical and machine learning methodologies to assess the various modalities used in medical image analysis. Specific to prostate cancer, the radiomics pipeline has multiple facets that are amenable to improvement. This review discusses the steps of a magnetic resonance imaging based radiomics pipeline. Present successes, existing opportunities for refinement, and the most pertinent pending steps leading to clinical validation are highlighted.

Abstract

The management of prostate cancer (PCa) is dependent on biomarkers of biological aggression. This includes an invasive biopsy to facilitate a histopathological assessment of the tumor’s grade. This review explores the technical processes of applying magnetic resonance imaging based radiomic models to the evaluation of PCa. By exploring how a deep radiomics approach further optimizes the prediction of a PCa’s grade group, it will be clear how this integration of artificial intelligence mitigates existing major technological challenges faced by a traditional radiomic model: image acquisition, small data sets, image processing, labeling/segmentation, informative features, predicting molecular features and incorporating predictive models. Other potential impacts of artificial intelligence on the personalized treatment of PCa will also be discussed. The role of deep radiomics analysis-a deep texture analysis, which extracts features from convolutional neural networks layers, will be highlighted. Existing clinical work and upcoming clinical trials will be reviewed, directing investigators to pertinent future directions in the field. For future progress to result in clinical translation, the field will likely require multi-institutional collaboration in producing prospectively populated and expertly labeled imaging libraries.

Do patients with a PI-RADS 5 lesion identified on magnetic resonance imaging require systematic biopsy in addition to targeted biopsy?

INTRODUCTION

Magnetic Resonance Imaging (MRI)-targeted prostate biopsy (MRI-TB) improves the detection of prostate cancer. These biopsies typically involve both a 12-core systematic biopsy (SB) and MRI-TB of the lesion. Since the majority of PI-RADS 5 lesions represent clinically significant cancers, the utility of SB in addition to MRI-TB is unclear. We evaluate the utility of SB in the setting of PI-RADS 5 lesions in biopsy naïve and active surveillance patients.

METHODS

Patients undergoing MRI-TB+SB with a PI-RADS 5 lesion were retrospectively reviewed in a prospectively collected database. Pathology obtained from the MRI-TB was then compared to that of the SB, and each was reported based on the highest Gleason Grade from the sample. In patients with a prior biopsy, we identified instances in which the MRI-TB+SB resulted in upgraded pathology and further subdivided these patients based on whether the pathology upgrade was a result of the TB or the SB.

RESULTS

We identified PI-RADS 5 lesions in 97 patients. All lesions biopsied were found to be prostate cancer, and 86.9% were clinically significant. Gleason Grade from the MRI-TB of the PI-RADS 5 lesions was the same or higher to that of the SB in all but 3 cases (3.1%). Among 59 patients with a prior prostate biopsy, 54 had upgraded pathology from MRI-TB+SB (91.5%). Of these 54 patients, MRI-TB pathology of the PI-RADS 5 lesion was the same or higher to that of the SB in 52 patients (96.3%). In all patients with higher Gleason Grade on SB than MRI-TB, the MRI-TB demonstrated GG3 or higher and SB did not change subsequent clinical management.

CONCLUSION

In the presence of a PI-RADS 5 lesion, SB offers minimal additional clinical value and could potentially be omitted when performing MRI-TB.

Consecutive transperineal prostatic template biopsies employing cognitive and systematic approach: a single center study

INTRODUCTION

The role of transperineal template biopsy for prostate cancer diagnosis is well established. Pre-biopsy multiparametric magnetic resonance imaging (MRI) is used in most centers for planning of prostate biopsies and staging. Cognitive and software fusion techniques are increasingly getting popular.

METHODS

We retrospectively reviewed patients who underwent transperineal template biopsies from January 2016 till December 2018. This included patients on active surveillance, previous negative transrectal ultrasonography biopsies with persistently raised prostate-specific antigen/abnormal prostate on digital rectal examination and de-novo template biopsies. Two specialist uro-radiologists reported all the scans and the biopsies were performed by one experienced urologist. The cognitive biopsies were performed for PIRADS 3-5 lesions on MRI. Total of 330 patients underwent transperineal template biopsies and cognitive target biopsies were carried out in 75 patients who were included in the study. We evaluated the results as positive/negative cognitive biopsies and also according to the PIRAD scoring. Only the patients with prostate cancer on template biopsy histology were included.

RESULTS

Fifty-seven (76%) of the cognitive biopsies were positive out of total 75.[Table: see text].

CONCLUSIONS

Combined cognitive and systematic biopsies have excellent diagnostic rate especially for PIRAD 4-5 MRI areas.

PI-RADS: what is new and how to use it

The prostate imaging reporting and data system (PI-RADS) has revolutionized the use of magnetic resonance imaging (MRI) for the management of prostate cancer (PCa). The most recent version 2.1, PI-RADS v2.1, provides specific refinements in the performance, relaxing some recommendations which were not found to be helpful, while reinforcing and clarifying others. The interpretation of T2-weighted imaging (T2WI) in the transition zone (TZ), and the overall assessment of TZ nodules, now allows for a clearer distinction between those which are clearly benign and those which might warrant tissue sampling. Additional changes also resolve discrepancies in T2WI and diffusion-weighted imaging (DWI) of the peripheral zone (PZ). PI-RADS v2.1 is a simpler, more straightforward, and more reproducible method to better communicate between physicians regarding findings on prostate MRI.

Clinical proteomics for prostate cancer: understanding prostate cancer pathology and protein biomarkers for improved disease management

Following the introduction of routine Prostate Specific Antigen (PSA) screening in the early 1990′s, Prostate Cancer (PCa) is often detected at an early stage. There are also a growing number of treatment options available and so the associated mortality rate is generally low. However, PCa is an extremely complex and heterogenous disease and many patients suffer disease recurrence following initial therapy. Disease recurrence commonly results in metastasis and metastatic PCa has an average survival rate of just 3–5 years. A significant problem in the clinical management of PCa is being able to differentiate between patients who will respond to standard therapies and those who may benefit from more aggressive intervention at an earlier stage. It is also acknowledged that for many men the disease is not life threatenting. Hence, there is a growing desire to identify patients who can be spared the significant side effects associated with PCa treatment until such time (if ever) their disease progresses to the point where treatment is required. To these important clinical needs, current biomarkers and clinical methods for patient stratification and personlised treatment are insufficient. This review provides a comprehensive overview of the complexities of PCa pathology and disease management. In this context it is possible to review current biomarkers and proteomic technologies that will support development of biomarker-driven decision tools to meet current important clinical needs. With such an in-depth understanding of disease pathology, the development of novel clinical biomarkers can proceed in an efficient and effective manner, such that they have a better chance of improving patient outcomes.

MRI-targeted biopsy versus standard transrectal ultrasound-guided biopsy: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

For men with a suspicion of prostate cancer (PCa), the transrectal ultrasound-guided biopsy (TRUS-Bx) was recommended. Multi-parametric magnetic resonance imaging (mp-MRI) could be more useful to more accurately selected patients who are with a clinical suspicion of PCa and eligible for biopsy, and avoid a biopsy if the result was negative. In the present study, we compared the MRI-targeted biopsy (MRI-TBx) with TRUS-Bx.

METHODS

We searched the following online database: PubMed, Embase, and Cochrane Library, and the search was updated to March 2019.

RESULTS

Finally, a total of 8 randomized controlled trials (RCTs) comprising 2593 patients were enrolled in the final analysis. MRI-TBx and TRUS-Bx did not significantly differ in overall PCa (RR = 1.30; 95% CI 0.98-1.72; P = 0.067), clinically significant PCa (RR = 1.35; 95% CI 0.98-1.86; P = 0.065), and clinically insignificant PCa (RR = 0.76; 95% CI 0.40-1.46; P = 0.416). While in patients with initial biopsy, MRI-TBx had a significantly higher detection rate of overall PCa (RR = 1.40; 95% CI 1.01-1.94; P = 0.045).

CONCLUSION

In the present study, we found that MRI-TBx potentially benefits the detection of overall and clinically significant PCa compared with TRUS-Bx in patients with a suspicion of PCa. Furthermore, in patients with initial biopsy, MRI-TBx had a significantly higher detection rate of overall PCa and a potentially higher detection rate of clinically significant PCa. While for patients with prior negative biopsy, we did not detect significant differences in overall and clinically significant PCa between two groups. More large and multicenter RCTs are further required.

The role of multiparametric magnetic resonance imaging and magnetic resonance-guided biopsy in active surveillance for low-risk prostate cancer: A systematic review

The performance of multiparametric magnetic resonance imaging (mpMRI) and subsequent biopsy in monitoring prostate cancer in men on active surveillance (AS) have not been defined clearly. In this systematic review, we aimed to review current literature about the usage of MRI examination in men with low-risk prostate cancer during active surveillance. For that, we searched seven databases to include all studies reporting magnetic resonance imaging in the AS of low-risk prostate cancer. We finally included 11 studies with 1237 patients included. Our results showed an adequate sensitivity and specificity of both modalities to detect disease progression; including disease upgrading and upstaging. However, the performance in the prediction of unfavorable disease was inferior to the detection of upgrading and upstaging. In terms of MRGB, the previous literature agreed on the superiority of using a combination of different biopsy schemes to get a better progression section. Noteworthy, mp-MRI and MRGB had a good predictive value limited to the first year, with TRUSGB showing a superior role in detecting patients with a GS ≥ 7, after that. In conclusion, both of mpMRI and MRGB have shown an adequate performance on assessing disease progression in the AS of low-risk prostate cancer patients. They can be used for disease staging and grading for successful treatment planning.

•

In comparison to the literature, few papers discuss the benefit of MRI screening in low-risk prostate cancer groups.

•

Biopsy is considered more invasive than MRI, thus reducing the burden of such methods on the patients.

•

PSA values can be misinterpreted especially that it can rise in other diseases such as Benign Prostatic Hyperplasia.

Design, Development, and Multi-Characterization of an Integrated Clinical Transrectal Ultrasound and Photoacoustic Device for Human Prostate Imaging

The standard diagnostic procedure for prostate cancer (PCa) is transrectal ultrasound (TRUS)-guided needle biopsy. However, due to the low sensitivity of TRUS to cancerous tissue in the prostate, small yet clinically significant tumors can be missed. Magnetic resonance imaging (MRI) with TRUS fusion biopsy has recently been introduced as a way to improve the identification of clinically significant PCa in men. However, the spatial errors in coregistering the preprocedural MRI with the real-time TRUS causes false negatives. A real-time and intraprocedural imaging modality that can sensitively detect PCa tumors and, more importantly, differentiate aggressive from nonaggressive tumors could largely improve the guidance of biopsy sampling to improve diagnostic accuracy and patient risk stratification. In this work, we seek to fill this long-standing gap in clinical diagnosis of PCa via the development of a dual-modality imaging device that integrates the emerging photoacoustic imaging (PAI) technique with the established TRUS for improved guidance of PCa needle biopsy. Unlike previously published studies on the integration of TRUS with PAI capabilities, this work introduces a novel approach for integrating a focused light delivery mechanism with a clinical-grade commercial TRUS probe, while assuring much-needed ease of operation in the transrectal space. We further present the clinical potential of our device by (i) performing rigorous characterization studies, (ii) examining the acoustic and optical safety parameters for human prostate imaging, and (iii) demonstrating the structural and functional imaging capabilities using deep-tissue-mimicking phantoms. Our TRUSPA experimental studies demonstrated a field-of-view in the range of 130 to 150 degrees and spatial resolutions in the range of 300 μm to 400 μm at a soft tissue imaging depth of 5 cm.

The Movember Prostate Cancer Landscape Analysis: an assessment of unmet research needs

Prostate cancer is a heterogeneous cancer with widely varying levels of morbidity and mortality. Approaches to prostate cancer screening, diagnosis, surveillance, treatment and management differ around the world. To identify the highest priority research needs across the prostate cancer biomedical research domain, Movember conducted a landscape analysis with the aim of maximizing the effect of future research investment through global collaborative efforts and partnerships. A global Landscape Analysis Committee (LAC) was established to act as an independent group of experts across urology, medical oncology, radiation oncology, radiology, pathology, translational research, health economics and patient advocacy. Men with prostate cancer and thought leaders from a variety of disciplines provided a range of key insights through a range of interviews. Insights were prioritized against predetermined criteria to understand the areas of greatest unmet need. From these efforts, 17 research needs in prostate cancer were agreed on and prioritized, and 3 received the maximum prioritization score by the LAC: first, to establish more sensitive and specific tests to improve disease screening and diagnosis; second, to develop indicators to better stratify low-risk prostate cancer for determining which men should go on active surveillance; and third, to integrate companion diagnostics into randomized clinical trials to enable prediction of treatment response. On the basis of the findings from the landscape analysis, Movember will now have an increased focus on addressing the specific research needs that have been identified, with particular investment in research efforts that reduce disease progression and lead to improved therapies for advanced prostate cancer.

The Movember global Landscape Analysis Committee (LAC) was established to act as an independent group of experts across urology, medical oncology, radiation oncology, radiology, pathology, translational research, health economics and patient advocacy to identify the highest priority research needs across the prostate cancer biomedical research domain. Findings from the landscape analysis illustrate the research priorities in prostate cancer and will enable Movember to focus on specific needs, with particular investment in research to reduce disease progression and improve therapies for advanced prostate cancer.

Automatic needle tracking using Mask R-CNN for MRI-guided percutaneous interventions

PURPOSE

Accurate needle tracking provides essential information for MRI-guided percutaneous interventions. Passive needle tracking using MR images is challenged by variations of the needle-induced signal void feature in different situations. This work aimed to develop an automatic needle tracking algorithm for MRI-guided interventions based on the Mask Region Proposal-Based Convolutional Neural Network (R-CNN).

METHODS

Mask R-CNN was adapted and trained to segment the needle feature using 250 intra-procedural images from 85 MRI-guided prostate biopsy cases and 180 real-time images from MRI-guided needle insertion in ex vivo tissue. The segmentation masks were passed into the needle feature localization algorithm to extract the needle feature tip location and axis orientation. The proposed algorithm was tested using 208 intra-procedural images from 40 MRI-guided prostate biopsy cases, and 3 real-time MRI datasets in ex vivo tissue. The algorithm results were compared with human-annotated references.

RESULTS

In prostate datasets, the proposed algorithm achieved needle feature tip localization error with median Euclidean distance (dxy) of 0.71 mm and median difference in axis orientation angle (dθ) of 1.28°, respectively. In 3 real-time MRI datasets, the proposed algorithm achieved consistent dynamic needle feature tracking performance with processing time of 75 ms/image: (a) median dxy = 0.90 mm, median dθ = 1.53°; (b) median dxy = 1.31 mm, median dθ = 1.9°; (c) median dxy = 1.09 mm, median dθ = 0.91°.

CONCLUSIONS

The proposed algorithm using Mask R-CNN can accurately track the needle feature tip and axis on MR images from in vivo intra-procedural prostate biopsy cases and ex vivo real-time MRI experiments with a range of different conditions. The algorithm achieved pixel-level tracking accuracy in real time and has potential to assist MRI-guided percutaneous interventions.

Comparison of machine learning algorithms to predict clinically significant prostate cancer of the peripheral zone with multiparametric MRI using clinical assessment categories and radiomic features

Objectives

To analyze the performance of radiological assessment categories and quantitative computational analysis of apparent diffusion coefficient (ADC) maps using variant machine learning algorithms to differentiate clinically significant versus insignificant prostate cancer (PCa).

Methods

Retrospectively, 73 patients were included in the study. The patients (mean age, 66.3 ± 7.6 years) were examined with multiparametric MRI (mpMRI) prior to radical prostatectomy (n = 33) or targeted biopsy (n = 40). The index lesion was annotated in MRI ADC and the equivalent histologic slides according to the highest Gleason Grade Group (GrG). Volumes of interest (VOIs) were determined for each lesion and normal-appearing peripheral zone. VOIs were processed by radiomic analysis. For the classification of lesions according to their clinical significance (GrG ≥ 3), principal component (PC) analysis, univariate analysis (UA) with consecutive support vector machines, neural networks, and random forest analysis were performed.

Results

PC analysis discriminated between benign and malignant prostate tissue. PC evaluation yielded no stratification of PCa lesions according to their clinical significance, but UA revealed differences in clinical assessment categories and radiomic features. We trained three classification models with fifteen feature subsets. We identified a subset of shape features which improved the diagnostic accuracy of the clinical assessment categories (maximum increase in diagnostic accuracy ΔAUC = + 0.05, p < 0.001) while also identifying combinations of features and models which reduced overall accuracy.

Conclusions

The impact of radiomic features to differentiate PCa lesions according to their clinical significance remains controversial. It depends on feature selection and the employed machine learning algorithms. It can result in improvement or reduction of diagnostic performance.

Key Points

• Quantitative imaging features differ between normal and malignant tissue of the peripheral zone in prostate cancer.

• Radiomic feature analysis of clinical routine multiparametric MRI has the potential to improve the stratification of clinically significant versus insignificant prostate cancer lesions in the peripheral zone.

• Certain combinations of standard multiparametric MRI reporting and assessment categories with feature subsets and machine learning algorithms reduced the diagnostic performance over standard clinical assessment categories alone.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07064-5) contains supplementary material, which is available to authorized users.

The accuracy of prostate lesion localization in cognitive fusion

PURPOSE

Prostate cancer (PCa) is one of the most common cancers in elderly men worldwide. Systematic biopsy guided by transrectal ultrasound remains the standard for PCa diagnosis; however, the false negative rate is 10-20%. Multiparametric magnetic resonance imaging (mpMRI) allows PCa visualization with a more precise localization and a higher accuracy and specificity for the detection of PCa. The physician can mentally relocate the most appropriate area detected on the prebiopsy mpMRI, based on its zonal topography and anatomical landmarks, called cognitive fusion. Herein, we concentrated on the accuracy of PCa localization in cognitive fusion compared with MRI-TRUS fusion and explored the applied scope of cognitive fusion.

METHODS

Thirty-two eligible patients with 36 PCa lesions were recruited for our study. TRUS examinations and MRI-TRUS fusion procedures were performed by experienced operators. The cognitive fusion images were compared using the TRUS image in a MRI-TRUS fusion workstation.

RESULTS

Using cognitive fusion imaging, 86.1% of the lesions were accurately located by the senior sonographer and 69.4% of the lesions were accurately located by the junior sonographer. The maximum diameter and PI-RADS score of the lesions were important factors that affected the accuracy of cognitive fusion (P < 0.05). Furthermore, the lesions with high PI-RADS scores and the lesions with large diameters were more accurately located using cognitive fusion (P < 0.05).

CONCLUSIONS

Cognitive fusion is a reliable technique with dependency on working experience, and its accuracy of locating suspicious lesions is consistent with MRI-TRUS fusion in patients with high PI-RADS score and large lesions.

Prostate MRI with PI-RADS v2.1: initial detection and active surveillance

The role of prostate MRI in clinical practice has continued to broaden over time. Multiple iterations of PI-RADS reporting have aided in improving detection and reporting of prostate cancer. In addition, recent recommendations from the PI-RADS Steering Committee promote an MRI-first approach with an MRI-directed prostate cancer diagnostic pathway. It is imperative for radiologists to be knowledgeable and familiar with prostate MRI and PI-RADS recommendations, as there is an increasing demand for prostate imaging by clinicians and patients alike.

Comparison of Real-Time Virtual Sonography Navigation Versus BioJet Navigation on Magnetic Resonance Imaging-Guided Prostate Needle Biopsy: A Single Institutional Analysis

Objective: To analyze the effectiveness and complication rate of MRI-guided prostate needle biopsies by using real-time virtual sonography (RVS) vs BioJet navigation. Methods: We retrospectively reviewed 171 patients who underwent an MRI-guided prostate needle biopsy at our institution. Patients whose prostate-specific antigen level was >4.0 ng/mL and who had suspicious prostate cancer (PCa) lesions by multiparametric MRI (mpMRI) underwent 2-core MRI-guided targeted biopsy (TB) and for MRI-guided TB: RVS and BioJet. RVS navigation synchronized mpMRI images with transrectal ultrasound (TRUS) images. BioJet navigation used a software program that merged images from mpMRI and TRUS to produce a composite image. We retrospectively compared the detection rate of PCa and the frequency of severe adverse events (AEs) between these two navigation systems, focusing on patients. In addition, we compared the detection rate of MRI-guided TB cores of two navigation systems regarding anatomical position (transitional zone [TZ] or peripheral zone [PZ]). Results: Data from RVS and BioJet biopsy groups were from 65 and 106 patients, respectively. Of these, RVS-TB included 141 cores (PZ: 49 cores, TZ: 92 cores), and BioJet-TB included 276 cores (PZ: 73 cores, TZ: 203 cores). In detecting PCa, by conducting both systematic biopsy and TB, and AEs in patients, a significant difference was not noted between RVS and BioJet navigation systems. In addition, there was no significant difference in the total detection rate for PCa in TB cores between the two methods. However, in the TZ, BioJet navigation showed a significantly higher detection rate of PCa than RVS navigation (35.0% vs 17.4%, p = 0.0023) by analyzing the cores of MRI-guided TB. Conclusion: When targeting TZ lesions, BioJet navigation had a greater detection rate for PCa compared with that of RVS navigation.

Power Doppler Sonography (PDS) and Modified TRUS Systematic Biopsies - Can this Combination Adequately Replace Multiparametric Prostate Magnetic Resonance Imaging (mp-MRI) in Candidates for Re Biopsies Who cannot Undergo mp-MRI

The MRI targeted biopsy (MRI-TBx) may increase the detection rate of clinically significant cancer (csPCa) in candidates for re-biopsy. However, there will be several patients in whom MRI is contraindicated. In this retrospective study we assessed the ability of combination of PDS guided biopsies (PDS-TBx) and modified SBx to substitute MRI-TBx. 154 men with persistently elevated PSA were referred for re-biopsy. Our protocol included a combination of MRI-TBx, DPS-TBx and modified SBx with additional biopsies from anterior lateral horns and anterior aspects of apex. MRI findings were defined as suspicious lesions (MRI-SL) and highly suspicious lesions (MRI-HL), based on PIRADS scale. In 40 patients csPCa was detected. While, MRI diagnosed csPCa in 36 patients (23%, n-36/154): 25% and 92% of biopsies targeted to the MRI- SL and MRI-HSL confirmed csPCa. Thirty-eight PDS hypervascular areas were found, while csPCa was diagnosed in 84% of these lesions, or in 28 patients (18%, n-28/154). SBx detected csPCa in 34 cores or in 21 patients (13%, n - 21/154). SBx missed cancers in the in the anterior aspect of middle gland. Combination of PDS-TBx + SBx detected csPCa in 35 (88% of csPCa) patients. Strongest predictors for the csPCa presence were MRI-HSL, PDS' lesions and biopsies from anterior aspect that included apex, mid gland and anterior lateral horns (p < 0.001 and p-0.008, respectively). The combination of PDS-TBx + SBx may miss 15% of csPCa detected by MRI. However, it can detect additional 10% of csPCa that were missed by MRI. To improve the accuracy of this combination, the anterior aspect of middle gland should be also included in the modified SBx. These changes in combination can make it helpful in candidates for re-biopsy who cannot undergo MRI.

The decision of targeted, systematic or combined biopsy in a biopsy naïve patient for the diagnosis of prostate cancer, can be made on the basis of multiparametric magnetic resonance imaging

Introduction:

The current trend to implement multiparametric magnetic resonance imaging (mpMRI)-guided targeted biopsy (TB) as primary biopsy for the diagnosis of suspected prostate cancer and to avoid systematic biopsy (SB) is growing. However, concern remains regarding missing clinically significant (Cs) cancer on the normal mpMRI areas of the prostate. Therefore, we compared the normal and abnormal areas from mpMRI at the same prostate biopsy, using simultaneous SB and TB technique.

Methods:

A prospective, comparative effectiveness study included 134 patients initially referred for primary biopsy (from October 2017 to June 2018); 100 men were selected, mean age 68 years, with a median level of prostate specific antigen of 7.6, with average prostate volume of 52 cm3 (T3 disease and prostate imaging reporting and data system (PI-RADS) score < 3 were excluded). All underwent six cores TB (median), from an average of two lesions on mpMRI and also eight cores SB (median) from normal mpMRI areas of the prostate after informed consent.

Results:

The combined (SB + TB) biopsy cancer detection rate was 67%, 51% having Cs disease. For Cs cancer, 35 patients were detected by both techniques. TB missed four Cs cancer (95% confidence interval (CI), p < 0.0001). Fewer men in the TB group than in the SB group were found to have clinically insignificant (Ci) cancer (95% CI, p < 0.0001). No Cs cancer diagnosis was missed on TB from PI-RADS 5 lesion. Overall, 4% Cs cancers were missed on TB and avoided over diagnosis of 9% Ci cancer.

Conclusions:

Cognitive TB didn’t miss any Cs cancer from PI-RADS 5 lesion found on mpMRI. Only doing Cognitive TB on PI-RADS 5 lesion would save time, reduce workload and will be cost effective both for Urology and Pathology. PI-RADS 3 and 4 lesions on mpMRI will benefit from adding systematic samples.

Level of evidence:

4 Oxford Centre for Evidence-Based Medicine (CEBM).

Five-year Outcomes of Magnetic Resonance Imaging-based Active Surveillance for Prostate Cancer: A Large Cohort Study

Background

Although the use of multiparametric magnetic resonance imaging (mpMRI) in active surveillance (AS) for prostate cancer is of increasing interest, existing data are derived from small cohorts.

Objective

We describe clinical, histological, and radiological outcomes from an established AS programme, where protocol-based biopsies were omitted in favour of MRI-led monitoring.

Design, setting, and participants

Data on 672 men enrolled in AS between August 2004 and November 2017 (inclusion criteria: Gleason 3 + 3 or 3 + 4 localised prostate cancer, presenting prostate-specific antigen <20 ng/ml, and baseline mpMRI) were collected from the University College London Hospital (UCLH) database.

Outcome measurements and statistical analysis

Primary outcomes were event-free survival (EFS; event defined as prostate cancer treatment, transition to watchful waiting, or death) and treatment-free survival (TFS). Secondary outcomes included rates of all-cause or prostate cancer–related mortality, metastasis, and upgrading to Gleason ≥4 + 3. Data on radiological and histological progression were also collected.

Results and limitations

More than 3800 person-years (py) of follow-up were accrued (median: 58 mo; interquartile range 37–82 mo). Approximately 84.7% (95% confidence interval [CI]: 82.0–87.6) and 71.8% (95% CI: 68.2–75.6) of patients remained on AS at 3 and 5 yr, respectively. EFS and TFS were lower in those with MRI-visible (Likert 4–5) disease or secondary Gleason pattern 4 at baseline (log-rank test; p <  0.001). In total, 216 men were treated. There were 24 deaths, none of which was prostate cancer related (6.3/1000 py; 95% CI: 4.1–9.5). Metastases developed in eight men (2.1 events/1000 py; 95% CI: 1.0–4.3), whereas 27 men upgraded to Gleason ≥4 + 3 on follow-up biopsy (7.7 events/1000 py; 95% CI: 5.2–11.3).

Conclusions

The rates of discontinuation, mortality, and metastasis in MRI-led surveillance are comparable with those of standard AS. MRI-visible disease and/or secondary Gleason grade 4 at baseline are associated with a greater likelihood of moving to active treatment at 5 yr. Further research will concentrate on optimising imaging intervals according to baseline risk.

Patient summary

In this report, we looked at the outcomes of magnetic resonance imaging (MRI)-based surveillance for prostate cancer in a UK cohort. We found that this strategy could allow routine biopsies to be avoided. Secondary Gleason pattern 4 and MRI visibility are associated with increased rates of treatment. We conclude that MRI-based surveillance should be considered for the monitoring of small prostate tumours.

Can we improve the detection rate of prostate cancer using standard 12-core TRUS-guided prostate biopsy? Focused on the location of prostate biopsy

Background

We assessed the effect of biopsy location on the prostate cancer detection and clinically significant prostate cancer.

Methods

A total of 2774 patients with 12‐core prostate transrectal ultrasound‐guided prostate biopsy were included for per core analysis. Multivariate Cox regression analysis was performed to evaluate the effect of the location of biopsy on the prostate cancer and clinically significant prostate cancer detection.

Results

Prostate cancer was found in 775 patients (27.9%) and 576 prostate cancer patients (20.8%) were found to be clinically significant. The core length (P = .043), tumor length (P < .001), and % tumor length (P < .001) were significantly different according to the biopsy location. The detection rates for prostate cancer and clinically significant prostate cancer differed significantly according to the location of biopsy. Multivariate analysis revealed that the apical core was significantly related with increased detection of prostate cancer and clinically significant prostate cancer. The lateral core, in addition to apical core, was found to be significantly related with increased detection rates of prostate cancer and clinically significant prostate cancer in men with prostate‐specific antigen <10 ng/mL.

Conclusions

More in‐depth discussions on the location of standard 12‐core prostate biopsy are considered necessary. Apical core and lateral core biopsies may be helpful, especially in patients with prostate‐specific antigen ˂10 ng/mL if additional biopsies are planned following findings of no target lesions on imaging studies.

Efficacy and toxicity outcomes for patients treated with focal salvage high dose rate brachytherapy for locally recurrent prostate cancer

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Local recurrence of prostate cancer may be treated with salvage therapies.

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Focal salvage high dose rate brachytherapy provides good biochemical control.

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Severe genitourinary and gastrointestinal toxicities are low.

Introduction

Isolated local recurrence of prostate cancer following primary radiotherapy or brachytherapy may be treated with focal salvage high dose rate brachytherapy, although there remains an absence of high quality evidence to support this approach.

Methods

Men with prostate cancer treated consecutively between 2015 and 2018 using 19 Gy in a single fraction high dose rate brachytherapy (HDR) for locally recurrent prostate cancer were identified from an institutional database. Univariable analysis was performed to evaluate the relationship between patient, disease and treatment factors with biochemical progression free survival (bPFS).

Results

43 patients were eligible for evaluation. Median follow up duration was 26 months (range 1–60). Median bPFS was 35 months (95% confidence interval 25.6–44.4). Kaplan-Meier estimates for bPFS at 1, 2 and 3 years post salvage were 95.2%, 70.6% and 41.8% respectively. On univariable Cox regression analysis, only nadir PSA was significantly associated with bPFS although the majority of patients were also treated with androgen deprivation therapy. Only one late grade 3 genitourinary toxicity was observed.

Conclusion

Focal salvage HDR brachytherapy may provide good biochemical control with a low risk of severe toxicity. Further evaluation within clinical trials are needed to establish its role in the management of locally recurrent prostate cancer.

Cartography-based quality control of prostate cancer care: a necessary ground to targeted focal therapy

PURPOSE OF REVIEW

We summarize the evidence on accurate target definition, precise imaging, and guiding systems that are a necessary ground to targeted focal therapy.

RECENT FINDINGS

Accurate target detection is based on the ability of imaging to locate and characterize precisely the tumor burden and differentiation inside the prostate. There is a clear correlation with the multiparametric MRI (mpMRI) images and the morphologic attributes of the tumor. Limitations stem from the heterogeneity and the multifocality of prostate cancer. Some prostate cancers are MRI-negative tumors. Safety margins should also be elaborated based on the tumor grade and burden. PET prostate specific membrane antigen is another promising technology yielding same results as multiparametric MRI for primary detection of prostate cancer, but PET/MRI imaging is promising. Perfect guiding requires sophisticated software with good quality control to track the needle inside the prostate and to record the position allowing recall when second look biopsy, active surveillance, or targeted focal therapy are required.

SUMMARY

The multimodal fusion cartography model proves effective and necessary to fulfill preoperative and postoperative requirements for targeted focal therapy.

Merging new-age biomarkers and nanodiagnostics for precision prostate cancer management

The accurate identification and stratified treatment of clinically significant early-stage prostate cancer have been ongoing concerns since the outcomes of large international prostate cancer screening trials were reported. The controversy surrounding clinical and cost benefits of prostate cancer screening has highlighted the lack of strategies for discriminating high-risk disease (that requires early treatment) from low-risk disease (that could be managed using watchful waiting or active surveillance). Advances in molecular subtyping and multiomics nanotechnology-based prostate cancer risk delineation can enable refinement of prostate cancer molecular taxonomy into clinically meaningful and treatable subtypes. Furthermore, the presence of intertumoural and intratumoural heterogeneity in prostate cancer warrants the development of novel nanodiagnostic technologies to identify clinically significant prostate cancer in a rapid, cost-effective and accurate manner. Circulating and urinary next-generation prostate cancer biomarkers for disease molecular subtyping and the newest complementary nanodiagnostic platforms for enhanced biomarker detection are promising tools for precision prostate cancer management. However, challenges in merging both aspects and clinical translation still need to be overcome.

68Ga-PSMA PET/CT better characterises localised prostate cancer after MRI and transperineal prostate biopsy: Is 68Ga-PSMA PET/CT guided biopsy the future?

BACKGROUND

68Ga prostate specific membrane antigen PET/CT (68Ga-PSMA PET/CT) may be superior to multiparametric MRI (mpMRI) for localisation of prostate cancer tumour foci, however the concordance and differences between 68Ga-PSMA PET/CT and mpMRI when applied to all biopsied patients and potential benefit in patients with negative mpMRI is unclear.

METHODS

Retrospective analysis of patients undergoing mpMRI, prostate biopsy and 68Ga-PSMA PET/CT over a 3-year period. Diagnostic performance of 68Ga-PSMA PET/CT and mpMRI were assessed using biopsy histopathology for the entire cohort and radical prostatectomy specimen in a subset of patients. Lesion concordance and additional detection of each modality were determined, including in a dedicated cohort of patients with mpMRI PIRADS 2 scans.

RESULTS

A total of 144 patients were included in the study. Index lesion/foci detection was similar between 68Ga-PSMA PET/CT and mpMRI (sensitivity 83.1% vs 90.1%; p = 0.267), however lesions missed by mpMRI were larger (1.66 cm³ vs 0.72 cm³; p = 0.034). Lesion detection rates were similar across the biopsy histopathology and radical prostatectomy specimen subset, with a high concordance for index (80.1%) and a moderate concordance for total (67%) lesions between the 2 imaging modalities. The additional detection yield favoured 68Ga-PSMA PET/CT over mpMRI for index (13.5% vs 4.3%) and total (18.2% vs 5.4%) lesions; both modalities missed 2.1% and 12.3% of index and total lesions, respectively. 68Ga-PSMA PET/CT identified 9 of 11 patients with PIRADS 2 mpMRI but subsequently diagnosed with Gleason ≥ 3 + 4 disease.

CONCLUSIONS

Despite high concordance rates, 68Ga-PSMA PET/CT incrementally improved tumour localisation compared with mpMRI. These results suggest that 68Ga-PSMA PET/CT may have an incremental value to that of mpMRI in the diagnostic process for prostate.