Current status of MRI for the diagnosis, staging and prognosis of prostate cancer: implications for focal therapy and active surveillance

A Model for Predicting Clinically Significant Prostate Cancer Using Prostate MRI and Risk Factors

PURPOSE

The aim of this study was to develop and validate a predictive model for clinically significant prostate cancer (csPCa) using prostate MRI and patient risk factors.

METHODS

In total, 960 men who underwent MRI from 2015 to 2019 and biopsy either 6 months before or 6 months after MRI were identified. Men diagnosed with csPCa were identified, and csPCa risk was modeled using known patient factors (age, race, and prostate-specific antigen [PSA] level) and prostate MRI findings (location, Prostate Imaging Reporting and Data System score, extraprostatic extension, dominant lesion size, and PSA density). csPCa was defined as Gleason score sum ≥ 7. Using a derivation cohort, a multivariable logistic regression model and a point-based scoring system were developed to predict csPCa. Discrimination and calibration were assessed in a separate independent validation cohort.

RESULTS

Among 960 MRI reports, 552 (57.5%) were from men diagnosed with csPCa. Using the derivation cohort (n = 632), variables that predicted csPCa were Prostate Imaging Reporting and Data System scores of 4 and 5, the presence of extraprostatic extension, and elevated PSA density. Evaluation using the validation cohort (n = 328) resulted in an area under the curve of 0.77, with adequate calibration (Hosmer-Lemeshow P = .58). At a risk threshold of >2 points, the model identified csPCa with sensitivity of 98.4% and negative predictive value of 78.6% but prevented only 4.3% potential biopsies (0-2 points; 14 of 328). At a higher threshold of >5 points, the model identified csPCa with sensitivity of 89.5% and negative predictive value of 70.1% and avoided 20.4% of biopsies (0-5 points; 67 of 328).

CONCLUSIONS

The point-based model reported here can potentially identify a vast majority of men at risk for csPCa, while avoiding biopsy in about 1 in 5 men with elevated PSA levels.

MR Molecular Imaging of Extradomain-B Fibronectin for Assessing Progression and Therapy Resistance of Prostate Cancer

Accurate assessment and characterization of the progression and therapy response of prostate cancer are essential for precision healthcare of patients diagnosed with the disease. MRI is a clinical imaging modality routinely used for diagnostic imaging and treatment planning of prostate cancer. Extradomain B fibronectin (EDB-FN) is an oncofetal subtype of fibronectin highly expressed in the extracellular matrix of aggressive cancers, including prostate cancer. It is a promising molecular target for the detection and risk-stratification of prostate cancer with high-resolution MR molecular imaging (MRMI). In this study, we investigated the effectiveness of MRMI with an EDB-FN specific contrast agent MT218 for assessing the progression and therapy resistance of prostate cancer. Low grade LNCaP prostate cancer cells became an invasive phenotype LNCaP-CXCR2 with elevated EDB-FN expression after acquisition of the C-X-C motif chemokine receptor 2 (CXCR2). MT218-MRMI showed brighter signal enhancement in LNCaP-CXCR2 tumor xenografts with a ∼2-fold contrast-to-noise (CNR) increase than in LNCaP tumors in mice. Enzalutamide-resistant C4-2-DR prostate cancer cells were more invasive, with higher EDB-FN expression than parental C4-2 cells. Brighter signal enhancement with a ∼2-fold CNR increase was observed in the C4-2-DR xenografts compared to that of C4-2 tumors in mice with MT218-MRMI. Interestingly, when invasive PC3 prostate cancer cells developed resistance to paclitaxel, the drug-resistant PC3-DR cells became less invasive with reduced EDB-FN expression than the parental PC3 cells. MT218-MRMI detected reduced brightness in the PC3-DR xenografts with more than 2-fold reduction of CNR compared to PC3 tumors in mice. The signal enhancement in all tumors was supported by the immunohistochemical staining of EDB-FN with the G4 monoclonal antibody. The results indicate that MRMI of EDB-FN with MT218 has promise for detection, risk stratification, and monitoring the progression and therapy response of invasive prostate cancer.

Interactive Cascaded Network for Prostate Cancer Segmentation from Multimodality MRI with Automated Quality Assessment

The accurate segmentation of prostate cancer (PCa) from multiparametric MRI is crucial in clinical practice for guiding biopsy and treatment planning. Existing automated methods often lack the necessary accuracy and robustness in localizing PCa, whereas interactive segmentation methods, although more accurate, require user intervention on each input image, thereby limiting the cost-effectiveness of the segmentation workflow. Our innovative framework addresses the limitations of current methods by combining a coarse segmentation network, a rejection network, and an interactive deep network known as Segment Anything Model (SAM). The coarse segmentation network automatically generates initial segmentation results, which are evaluated by the rejection network to estimate their quality. Low-quality results are flagged for user interaction, with the user providing a region of interest (ROI) enclosing the lesions, whereas for high-quality results, ROIs were cropped from the automatic segmentation. Both manually and automatically defined ROIs are fed into SAM to produce the final fine segmentation. This approach significantly reduces the annotation burden and achieves substantial improvements by flagging approximately 20% of the images with the lowest quality scores for manual annotation. With only half of the images manually annotated, the final segmentation accuracy is statistically indistinguishable from that achieved using full manual annotation. Although this paper focuses on prostate lesion segmentation from multimodality MRI, the framework can be adapted to other medical image segmentation applications to improve segmentation efficiency while maintaining high accuracy standards.

Prostate cancer mortality rates in low- and favorable intermediate-risk active surveillance patients: a population-based competing risks analysis

PURPOSE

To determine prostate cancer (PCa) and other-cause mortality rates in low- and favorable intermediate-risk (FIR) active surveillance (AS) patients.

METHODS

The SEER Prostate with Watchful Waiting database was used to identify men diagnosed with NCCN low or FIR PCa, between 2010 and 2015, managed with AS. FIR patients were subdivided into three subgroups, based on their intermediate risk factor: grade group two (GG2), PSA 10-20 ng/ml or cT2b-c disease. Cumulative incidence function curves with other-cause mortality as the competing risk were utilized. Predictors of PCa mortality were assessed using multivariable regression analysis with semi-parametric proportional hazards modeling.

RESULTS

Among 70,871 patients, 48,127 (67.9%) had low and 22,744 (32.1%) had FIR disease. Median patient age was 64.0 years, and median PSA was 5.70 ng/ml. Median follow-up was 49.0 months. There were 166 (0.2%) PCa and 3,176 (4.48%) other-cause mortalities. The 5-year mortality rates in the low and FIR cohorts overall were 0.29% and 0.28%, respectively (p = 0.64). Within the FIR cohort, the corresponding rates were highest in the PSA 10-20 ng/ml subgroup at 0.73%, followed by 0.32% for GG2 FIR and 0.052% for cT2b-c FIR disease (p < 0.001). Older age at diagnosis (sHR 2.38, p = 0.006), Medicaid insurance (sHR: 2.58, p < 0.001), low socioeconomic (sHR 1.39, p = 0.032), and non-married statuses (sHR: 2.58, p < 0.001) were associated with increased PCa mortality.

CONCLUSION

Intermediate-term PCa mortality rates in FIR PCa patients are non-significantly different to those with low-risk PCa. However, there is significant within-group heterogeneity, with PCa mortality rates significantly higher in the PSA 10-20 subgroup.

Prediction of Prostate Cancer Aggressiveness Using a Novel Multiparametric Magnetic Resonance Imaging Parameter: Tumor Heterogeneity Index

<b><i>Background and Aims:</i></b> The aim of this study was to evaluate if the tumor heterogeneity index can predict the aggressiveness of prostate cancer (PCa) in patients diagnosed by magnetic resonance imaging (MRI) fusion biopsy. <b><i>Material and Methods:</i></b> Patients who underwent MRI fusion prostatic biopsy between July 2019 and December 2020 were retrospectively reviewed. Tumor heterogeneity index (coefficient of variation [CV]) and PI-RADS v2.1 scoring were analyzed by using multiparametric MRI. The patients were divided into 3 groups according to the risk classification, and the correlation between tumor heterogeneity index and PCa aggressiveness was studied by using apparent diffusion coefficient (ADC_mean and ADC_cv), Gleason score (GS), and risk classifications. <b><i>Results:</i></b> One hundred two patients were included in this study. Patients were evaluated as low-risk (group 1) (<i>n</i> = 35), moderate-risk (group 2) (<i>n</i> = 37), and high-risk (group 3) (<i>n</i> = 30). ADC_mean values for all groups were significantly different (<i>p</i> &#x3c; 0.0001). ADC_cv tumor heterogeneity index values were higher in group 2 and group 3 by the score increases in subgroups according to GS, while being higher than group 1 (<i>p</i> &#x3c; 0.001). The multivariate analysis revealed that prostate-specific antigen, PI-RADS, ADC_mean, and ADC_cv values were predictive for tumor aggressiveness. <b><i>Conclusion:</i></b> ADC_cv value as a tissue texture parameter can be used as a new biomarker to evaluate tumor aggressiveness in patients with PCa.

Artificial intelligence and imaging biomarkers for prostate radiation therapy during and after treatment

Magnetic resonance imaging (MRI) is increasingly used in the management of prostate cancer (PCa). Quantitative MRI (qMRI) parameters, derived from multi-parametric MRI, provide indirect measures of tumour characteristics such as cellularity, angiogenesis and hypoxia. Using Artificial Intelligence (AI), relevant information and patterns can be efficiently identified in these complex data to develop quantitative imaging biomarkers (QIBs) of tumour function and biology. Such QIBs have already demonstrated potential in the diagnosis and staging of PCa. In this review, we explore the role of these QIBs in monitoring treatment response during and after PCa radiotherapy (RT). Recurrence of PCa after RT is not uncommon, and early detection prior to development of metastases provides an opportunity for salvage treatments with curative intent. However, the current method of monitoring treatment response using prostate-specific antigen levels lacks specificity. QIBs, derived from qMRI and developed using AI techniques, can be used to monitor biological changes post-RT providing the potential for accurate and early diagnosis of recurrent disease.

Pathologic upgrading in favorable intermediate risk active surveillance patients: Clinical heterogeneity and implications for active surveillance decision

INTRODUCTION

Current guidelines support active surveillance (AS) for select patients with favorable intermediate risk (FIR) prostate cancer (CaP). A significant proportion of FIR CaP patients undergoing surgical treatment are found to have evidence of adverse pathology. Our objective was to determine the incidence and predictors of pathologic upgrading in FIR AS patients undergoing radical prostatectomy.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results Prostate with Watchful Waiting (WW) database was used to identify men younger than 80 years with National Comprehensive Cancer Network FIR CaP initially opting for AS and/or WW between 2010 and 2015 and subsequently underwent radical prostatectomy at least one year following diagnosis. Patients were assigned into one of three subgroups based on their intermediate risk factor: Gleason Score 7(3 + 4) (Group 1), prostate specific antigen level of 10-20 ng/ml (Group 2), and cT2b-c (Group 3). Pathologic upgrading was present in Group 1 if pathologic GS was 7 (4 + 3) or worse. For patients in Groups 2 and 3, upgrading occurred if pathologic GS was 7 (3 + 4) or worse. Oncologic and sociodemographic predictors of pathologic upgrading were evaluated univariable and multivariable logistic regression analysis.

RESULTS

18,760 patients were identified. Pathologic upgrading occurred in 138 (13.3%), 59 (25.0%), and 8,011 (45.8%) patients in groups 1, 2, and 3 respectively. Pathologic downgrading occurred in 226 (21.7%) patients in group 1. Significant predictors of pathologic upgrading on multivariable analysis included older age at diagnosis: 70 to 79 vs. 40 to 49 years (Groups 1 and 3, P < 0.05), a more recent diagnosis: 2014 to2015 vs. 2010-2011 (Groups 2 and 3, P < 0.005), higher volume disease: 37.5% to 49.9% vs. 0% to 12.4% (Groups 2 and 3, P < 0.005), and clinically palpable disease (Groups 1 and 2, P < 0.05). Additional risk factors for upgrading included uninsured or Medicaid status, diagnosis in a Western region (Group 2), African American ethnicity and higher socioeconomic status (Group 3) CONCLUSIONS: FIR CaP is a clinically heterogeneous risk group with incidence of pathologic upgrading ranging from 13.3% in those with GS 7 (3 + 4) to 45.8% in those with cT2b-c disease. Risk of pathologic upgrading in FIR CaP patients initially managed with AS and/or WW is significantly associated with multiple patient-level oncologic and sociodemographic variables.

Extraprostatic extension in prostate cancer: primer for radiologists

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

Management of prostate cancer after holmium laser enucleation of the prostate

INTRODUCTION

Holmium laser enucleation of the prostate (HoLEP) is effective in treating lower urinary tract symptoms from prostatic disease. We investigate the role of HoLEP in the management of patients with benign prostatic hypertrophy (BPH) and prostate cancer (CaP).

METHODS

Retrospective review of data regarding all patients undergoing HoLEP at a single institution was performed. Pre- and postoperative PSA, multiparametric MRI, and pathology results were analyzed for those with CaP identified prior to or incidentally at HoLEP.

RESULTS

From February 2016 to February 2020, 201 patients underwent HoLEP. Twelve patients had CaP diagnosed before HoLEP: 6 patients with GG1 are on active surveillance (AS), 3 of 4 intermediate-risk patients are on AS and 1 received treatment for disease progression, and both high-risk CaP patients achieved symptomatic benefit from HoLEP and are receiving systemic therapy for CaP. Twenty-one patients (11.1%) with incidentally detected CaP at HoLEP remain on AS or watchful waiting based on clinical scenario.

CONCLUSION

Screening for CaP in HoLEP candidates with PSA and MRI is recommended given that >10% will have incidental CaP. After HoLEP for BPH/LUTS, patients with CaP can be surveilled with PSA and/or MRI. Further investigation is warranted to determine the durability of success of these approaches.

ANATOMY - SPARING LAPAROSCOPIC RADICAL PROSTATECTOMY… IS IT POSSIBLE?

The fact is that nerve- and fascial-sparing robot-assisted technique improves functional results of radical prostatectomy.The aim of study: to evaluate feasibility and effectiveness of anatomy-sparing radical prostatectomy performed by conventional laparoscopy.Material and methods: A total of 4025 patients with prostate cancer who underwent conventional lap radical prostatectomy (LRP) between 2010 and 2020 were retrospectively reviewed. After that only cases of anatomy-sparing technique were enrolled. The perioperative parameters of these 714 men were analyzed. Continence was defined by “Pad-test” 1 or none.Results: There were no mortality, intra- and Clavien ≥ III postoperative complications i.q. conversions to open surgery. Average OR time & EBL – 155,3 min & 187,2 ml respectively. Mean time of bladder catheterization – 7,4 d. The frequency of positive surgical margins – 9,7%. Immediate and absolute continence has been reached in 38,2% of cases. In the other 42,3% of patients the “Pad-test” was not more than one. Thus 80,5% of our patients were satisfied with urination after surgery. Conclusions: conventional laparoscopic surgical technique described in this paper is not only feasible effective and safe but also achieve a better functional result.

Multiparametric MRI and radiomics in prostate cancer: a review

Multiparametric MRI (mpMRI) is an imaging modality that combines anatomical MR imaging with one or more functional MRI sequences. It has become a versatile tool for detecting and characterising prostate cancer (PCa). The traditional role of mpMRI was confined to PCa staging, but due to the advanced imaging techniques, its role has expanded to various stages in clinical practises including tumour detection, disease monitor during active surveillance and sequential imaging for patient follow-up. Meanwhile, with the growing speed of data generation and the increasing volume of imaging data, it is highly demanded to apply computerised methods to process mpMRI data and extract useful information. Hence quantitative analysis for imaging data using radiomics has become an emerging paradigm. The application of radiomics approaches in prostate cancer has not only enabled automatic localisation of the disease but also provided a non-invasive solution to assess tumour biology (e.g. aggressiveness and the presence of hypoxia). This article reviews mpMRI and its expanding role in PCa detection, staging and patient management. Following that, an overview of prostate radiomics will be provided, with a special focus on its current applications as well as its future directions.

Prostate imaging features that indicate benign or malignant pathology on biopsy

Accurate diagnosis of clinically significant prostate cancer is essential in identifying patients who should be offered treatment with curative intent. Modifications to the Gleason grading system in recent years show that accurate grading and reporting at needle biopsy can improve identification of clinically significant prostate cancers. Extracapsular extension of prostate cancer has been demonstrated to be an adverse prognostic factor with greater risk of metastatic spread than organ-confined disease. Tumor volume may be an independent prognostic factor and should be considered in conjunction with other factors. Multi-parametric magnetic resonance imaging (MP-MRI) has become an increasingly important tool in the diagnosis and characterization of prostate cancer. MP-MRI allows T2-weighted (T2W) anatomical imaging to be combined with functional and physiological assessment. Diffusion-weighted imaging (DWI) has shown greater sensitivity, specificity and negative predictive value compared to prostate specific antigen (PSA) testing and T2W imaging alone and has a more positive correlation with Gleason score and tumour volume. Dynamic gadolinium contrast-enhanced (DCE) imaging can exhibit difficulties in distinguishing prostatitis from malignancy in the peripheral zone, and between benign prostatic hyperplasia (BPH) and malignancies in the transition zone (TZ). Computer aided diagnosis utilizes software to aid radiologists in detecting and diagnosing abnormalities from diagnostic imaging. New techniques of quantitative MRI, such as VERDICT MRI use tissue-specific factors to delineate different cellular and microstructural phenotypes, characterizing tissue properties with greater detail. Proton MR spectroscopic imaging (MRSI) is a more technically challenging imaging modality than DCE and DWI MRI. Over the last decade, choline and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) have developed as better tools for staging than conventional imaging. While hyperpolarized MRI shows promise in improving the imaging and differentiation of benign and malignant lesions there is further work required. Accurate reading and interpretation of diagnostic investigations is key to accurate identification of abnormal areas requiring biopsy, sparing those in whom benign or indolent disease can be managed by non-invasive means. Embracing and advancing existing technologies is essential in furthering this process.

All over the map: An interobserver agreement study of tumor location based on the PI-RADSv2 sector map

BACKGROUND

Prostate imaging reporting and data system version 2 (PI-RADSv2) recommends a sector map for reporting findings of prostate cancer mulitparametric MRI (mpMRI). Anecdotally, radiologists may demonstrate inconsistent reproducibility with this map.

PURPOSE

To evaluate interobserver agreement in defining prostate tumor location on mpMRI using the PI-RADSv2 sector map.

STUDY TYPE

Retrospective.

POPULATION

Thirty consecutive patients who underwent mpMRI between October, 2013 and March, 2015 and who subsequently underwent prostatectomy with whole-mount processing.

FIELD STRENGTH

3T mpMRI with T2 W, diffusion-weighted imaging (DWI) (apparent diffusion coefficient [ADC] and b-2000), dynamic contrast-enhanced (DCE).

ASSESSMENT

Six radiologists (two high, two intermediate, and two low experience) from six institutions participated. Readers were blinded to lesion location and detected up to four lesions as per PI-RADSv2 guidelines. Readers marked the long-axis of lesions, saved screen-shots of each lesion, and then marked the lesion location on the PI-RADSv2 sector map. Whole-mount prostatectomy specimens registered to the MRI served as ground truth. Index lesions were defined as the highest grade lesion or largest lesion if grades were equivalent.

STATISTICAL TEST

Agreement was calculated for the exact, overlap, and proportion of agreement.

RESULTS

Readers detected an average of 1.9 lesions per patient (range 1.6-2.3). 96.3% (335/348) of all lesions for all readers were scored PI-RADS ≥3. Readers defined a median of 2 (range 1-18) sectors per lesion. Agreement for detecting index lesions by screen shots was 83.7% (76.1%-89.9%) vs. 71.0% (63.1-78.3%) overlap agreement on the PI-RADS sector map (P < 0.001). Exact agreement for defining sectors of detected index lesions was only 21.2% (95% confidence interval [CI]: 14.4-27.7%) and rose to 49.0% (42.4-55.3%) when overlap was considered. Agreement on defining the same level of disease (ie, apex, mid, base) was 61.4% (95% CI 50.2-71.8%).

DATA CONCLUSION

Readers are highly likely to detect the same index lesion on mpMRI, but exhibit poor reproducibility when attempting to define tumor location on the PI-RADSv2 sector map. The poor agreement of the PI-RADSv2 sector map raises concerns its utility in clinical practice.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2018;48:482-490.

Initial risk stratification and staging in prostate cancer with prostatic-specific membrane antigen positron emission tomography/computed tomography: A first-stop-shop

Current imaging for prostate cancer (PCa) had limitations for risk stratification and staging. Magnetic resonance imaging frequently underestimated lymph node metastasis while bone scintigraphy often had diagnostic dilemmas. Prostatic-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT) has been remarkable in PCa recurrence. Ninety-seven PSMA PET-CT scans were reanalyzed for tumor node metastases staging and risk stratification of lymph node and distant metastasis proportion. Histopathology of 23/97 patients was available as gold standard. Chi-square test was used for proportion comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overestimation, underestimation, and correct estimation of T and N stages were calculated. Kappa coefficient (κ) was derived for inter-rater agreement. Lymph node or distant metastasis detection on PSMA PET/CT increased significantly with increase in risk category. PSMA PET/CT sensitivity, specificity, PPV, and NPV for extraprostatic extension, seminal vesicle invasion, and lymph node metastases were 63.16%, 100%, 100%, 36.36%; 55%, 100%, 100%, 25%; and 65.62%, 99.31%, 87.50%, and 97.53%, respectively. Kappa coefficient showed substantial agreement between PSMA PET/CT and histopathological lymph node metastases (κ = 0.734); however, it was just in fair agreement (κ = 0.277) with T stage. PSMA PET/CT overestimated, underestimated, and correct estimated T and N stages in 8.71%, 39.13%, 52.17% and 8.71%, 4.35%, and 86.96% cases, respectively. PSMA PET/CT has potential for initial risk stratification with reasonable correct N stage estimation, however underestimates T stage. Hence, we concluded that PSMA PET/CT should be used as “ first-stop-shop” for staging and initial risk stratification of PCa with regional magnetic resonance imaging in surgically resectable cases.

Multimodal Imaging in Focal Therapy Planning and Assessment in Primary Prostate Cancer

PURPOSE

There is increasing interest in focal therapy (male lumpectomy) of localized low-intermediate risk prostate cancer. Focal therapy is typically associated with low morbidity and provides the possibility of retreatment. Imaging is pivotal in stratification of men with localized prostate cancer for active surveillance, focal therapy or radical intervention. This article provides a concise review of focal therapy and the evolving role of imaging in this clinical setting.

METHODS

We performed a narrative and critical literature review by searching PubMed/Medline database from January 1997 to January 2017 for articles in the English language and the use of search keywords "focal therapy", "prostate cancer", and "imaging".

RESULTS

Most imaging studies are based on multiparametric magnetic resonance imaging. Transrectal ultrasound is inadequate independently but multiparametric ultrasound may provide new prospects. Positron emission tomography with radiotracers targeted to various underlying tumor biological features may provide unprecedented new opportunities. Multimodal Imaging appears most useful in localization of intraprostatic dominant index lesions amenable to focal therapy, in early assessment of therapeutic efficacy and potential need for additional focal treatments or transition to whole-gland therapy, and in predicting short-term and long-term outcomes.

CONCLUSION

Multimodal imaging is anticipated to play an increasing role in the focal therapy planning and assessment of low-intermediate risk prostate cancer and thereby moving this form of treatment option forward in the clinic.

Outcomes of combination MRI-targeted and transperineal template biopsy in restaging low-risk prostate cancer for active surveillance

Objective

Active surveillance (AS) offers a strategy to reduce overtreatment and now is a widely accepted treatment option for low-risk prostate cancer. An ideal tool for risk-stratification would detect aggressive cancers and exclude such men from taking up AS in the first place. We evaluate if a combination of transperineal template biopsy with magnetic resonance imaging (MRI)-targeted biopsy identifies significant prostate cancer amongst men initially diagnosed with low-risk prostate cancer.

Methods

This prospective, single-blinded study included men with low-risk prostate cancer (D'Amico's Criteria) diagnosed on conventional transrectal ultrasound-guided biopsy. Patients first underwent multiparametric MRI of the prostate ≥6 weeks after initial biopsy. Each suspicious lesion is mapped and assigned a Prostate Imaging Reporting and Data System (PIRADS) score. Template biopsy is first performed with the surgeon blinded to MRI findings followed by MRI-targeted biopsy using a robotic transperineal biopsy platform.

Results

The age of the 19 men included is 65.4 ± 4.9 years (mean ± SD). Prostate specific antigen (PSA) at diagnosis and at the time of transperineal biopsy were comparable (7.3 ± 1.7 ng/mL and 7.0 ± 1.8 ng/mL, p = 0.67), so were prostate volumes (34.2 ± 8.9 mL and 32.1 ± 13.4 mL, p = 0.28). MRI-targeted biopsy had a higher percentage of cancer detection per core compared to template biopsy (11.7% vs. 6.5%, p = 0.02), this was more than 3 times superior for Gleason 7 disease (5.9% vs. 1.6%, p < 0.01). Four of 18 (22.2%) patients with MRI lesions had significant disease with MRI-targeted biopsy alone. Three of 19 patients (15.8%) had significant disease with template biopsy alone. In combination, both techniques upclassified five patients (26.3%), all of whom underwent radical prostatectomy. Whole mount histology confirmed tumour location and grade. All six patients with PIRADS 5 lesions had cancer detected (66.6% significant disease).

Conclusion

A combination of MRI-targeted and template biopsy may optimally risk-classify “low-risk” patients diagnosed on initial conventional transrectal ultrasonography (TRUS) prostate biopsy.

Is contrast enhancement needed for diagnostic prostate MRI?

Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) provides clinical guidelines for multiparametric magnetic resonance imaging (mpMRI) [T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)] of prostate. However, DCE-MRI seems to show a limited contribution in prostate cancer (PCa) detection and management. In our experience, DCE-MRI, did not show significant change in diagnostic performance in addition to DWI and T2WI [biparametric MRI (bpMRI)] which represent the predominant sequences to detect suspected lesions in peripheral and transitional zone (TZ). In this article we reviewed the role of DCE-MRI also indicating the potential contribute of bpMRI approach (T2WI and DWI) and lesion volume evaluation in the diagnosis and management of suspected PCa.

Developing a nomogram based on multiparametric magnetic resonance imaging for forecasting high-grade prostate cancer to reduce unnecessary biopsies within the prostate-specific antigen gray zone

BACKGROUND

Since 1980s the application of Prostate specific antigen (PSA) brought the revolution in prostate cancer diagnosis. However, it is important to underline that PSA is not the ideal screening tool due to its low specificity, which leads to the possible biopsy for the patient without High-grade prostate cancer (HGPCa). Therefore, the aim of this study was to establish a predictive nomogram for HGPCa in patients with PSA 4-10 ng/ml based on Prostate Imaging Reporting and Data System version 2 (PI-RADS v2), MRI-based prostate volume (PV), MRI-based PV-adjusted Prostate Specific Antigen Density (adjusted-PSAD) and other traditional classical parameters.

METHODS

Between January 2014 and September 2015, Of 151 men who were eligible for analysis were formed the training cohort. A prediction model for HGPCa was built by using backward logistic regression and was presented on a nomogram. The prediction model was evaluated by a validation cohort between October 2015 and October 2016 (n = 74). The relationship between the nomogram-based risk-score as well as other parameters with Gleason score (GS) was evaluated. All patients underwent 12-core systematic biopsy and at least one core targeted biopsy with transrectal ultrasonographic guidance.

RESULTS

The multivariate analysis revealed that patient age, PI-RADS v2 score and adjusted-PSAD were independent predictors for HGPCa. Logistic regression (LR) model had a larger AUC as compared with other parameters alone. The most discriminative cutoff value for LR model was 0.36, the sensitivity, specificity, positive predictive value and negative predictive value were 87.3, 78.4, 76.3, and 90.4%, respectively and the diagnostic performance measures retained similar values in the validation cohort (AUC 0.82 [95% CI, 0.76-0.89]). For all patients with HGPCa (n = 50), adjusted-PSAD and nomogram-based risk-score were positively correlated with the GS of HGPCa in PSA gray zone (r = 0.455, P = 0.002 and r = 0.509, P = 0.001, respectively).

CONCLUSION

The nomogram based on multiparametric magnetic resonance imaging (mp-MRI) for forecasting HGPCa is effective, which could reduce unnecessary prostate biopsies in patients with PSA 4-10 ng/ml and nomogram-based risk-score could provide a more robust parameter of assessing the aggressiveness of HGPCa in PSA gray zone.

TRUS-MR Fusion Biopsy of the Prostate: Radiological and Histological Correlation

Objective

Targeted magnetic resonance/ultrasound fusion prostate biopsy has been shown to improve the detection of high-grade prostate cancer and to reduce sampling errors. Our objective is to assess MR-TRUS targeted fusion biopsy versus standard biopsy for the detection of clinically significant tumors.

Materials and Methods

Patients were referred for abnormal digital rectal examination (DRE) or risen prostate-specific antigen (PSA). If an MRI-visible lesion was detected, they were included in the study. In total, 102 men underwent MRI followed by MR-TRUS fusion biopsy between November 2014 and January 2016. Tumor grading was done with the clinical relevance in mind; a cutoff was used at Gleason 7 or higher. Standard biopsy results were collected from clinical practice during 2005 at the same institution to provide baseline values.

Results

A comparable rate of prostate cancer is found whether sampling is done at random (42.4%) or with the use of fusion biopsy (44.1%). However, these percentages are histologically different: fewer low-grade tumors are detected with MR-TRUS fusion biopsy (-19.1%), while more high-grade tumors are diagnosed (+26%). If there is an ultrasound-visible lesion in the prostate, the gain of combined MRI and fusion biopsy is less impressive.

Conclusion

Fusion biopsy can provide more accurate information for optimal patient management, as it detects a higher percentage of high-grade prostate cancers than random sampling. Furthermore, nonrelevant tumors are less commonly detected using fusion biopsy.

Prostate MRI based on PI-RADS version 2: how we review and report

Prostate imaging and interpretation is based on prostate imaging reporting and data system version 2 (PI-RADS™ v2) providing clinical guidelines for multiparametric magnetic resonance imaging (mpMRI) of the prostate. PI-RADS™ v2 aims to promote global standardisation, to diminish variation in the acquisition, interpretation and reporting of prostate mpMRI examinations and to improve detection, localisation, and risk stratification in patients with suspected cancer in treatment naïve prostate glands. It does not address detection of recurrence, progression during active surveillance and evaluation of other parts of the body.

PI-RADS™ v2 improves and standardises communication between radiologists and urologists to detect or exclude the presence of significant prostate cancer with a high likelihood. Findings on mpMRI are assessed on a 5-point category scale based on the probability that a combination of findings on T2-weighted (T2w) sequences, diffusion-weighted MRI (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) correlates with the presence of a clinically significant prostate cancer at a particular location. PI-RADS assessment categories range from 1 to 5 with 5 being most likely to represent clinically significant prostate cancer. The dominant sequence to detect prostate cancer in the peripheral zone is DWI, whereas for tumour detection in the transition zone T2w is the most important sequence. DCE-MRI has been attributed a minor role and only qualitative assessment with presence or absence of focal enhancement is suggested. Up to four suspicious lesions of category 3, 4 and 5 are assigned on a sector map and the index lesion should be identified.

PI-RADS version 2: what you need to know

Prostate cancer is the second most prevalent cancer in men worldwide and its incidence is expected to double by 2030. Multi-parametric magnetic resonance imaging (MRI) incorporating anatomical and functional imaging has now been validated as a means of detecting and characterising prostate tumours and can aid in risk stratification and treatment selection. The European Society of Urogenital Radiology (ESUR) in 2012 established the Prostate Imaging-Reporting and Data System (PI-RADS) guidelines aimed at standardising the acquisition, interpretation and reporting of prostate MRI. Subsequent experience and technical developments have highlighted some limitations, and a joint steering committee formed by the American College of Radiology, ESUR, and the AdMeTech Foundation have recently announced an updated version of the proposals. We summarise the main proposals of PI-RADS version 2, explore the evidence behind the recommendations, and highlight key differences for the benefit of those already familiar with the original.

PI-RADS Prostate Imaging - Reporting and Data System: 2015, Version 2

The Prostate Imaging - Reporting and Data System Version 2 (PI-RADS™ v2) is the product of an international collaboration of the American College of Radiology (ACR), European Society of Uroradiology (ESUR), and AdMetech Foundation. It is designed to promote global standardization and diminish variation in the acquisition, interpretation, and reporting of prostate multiparametric magnetic resonance imaging (mpMRI) examination, and it is based on the best available evidence and expert consensus opinion. It establishes minimum acceptable technical parameters for prostate mpMRI, simplifies and standardizes terminology and content of reports, and provides assessment categories that summarize levels of suspicion or risk of clinically significant prostate cancer that can be used to assist selection of patients for biopsies and management. It is intended to be used in routine clinical practice and also to facilitate data collection and outcome monitoring for research.

Evaluation of Multiparametric Magnetic Resonance Imaging in Detection and Prediction of Prostate Cancer

Background

Although European Society of Urogenital Radiology proposed the potential of multiparametric magnetic resonance imaging (MP-MRI) as a tool in the diagnostic pathway for prostate cancer (PCa) and published a unified scoring system named Prostate Imaging Reporting and Data System (PI-RADS version 1), these still need to be validated by real-life studies.

Objective

To evaluate the role of MP-MRI in detection and prediction of PCa.

Methods

Patients with clinical suspicion of PCa who underwent prebiopsy MP-MRI from 2002 to 2009 were recruited. MP-MRI results were retrospectively assigned as overall scores using PI-RADS by two radiologists. Patients were followed and the end point was the diagnosis of PCa. Receiver operating characteristics (ROC) curve was performed to test diagnostic efficacy of MP-MRI, under results of biopsy within three months. The cox proportional hazards model was used to identify independent variables for the detection of PCa.

Results

Finally, 1113 of the 1806 enrolled patients were included for analysis. The median follow-up was 56.0 months (1–137 mo). For 582 patients biopsied within three months, area under the curve for the detection of PCa with MP-MRI was 0.88 (95% confidence interval [CI], 0.75–1.00) in group of baseline prostate specific antigen (PSA) 0.01–4.00 ng/ml (n = 31), 0.90 (95% CI, 0.84–0.95) in PSA 4.01–10.00 ng/ml (n = 142), and 0.91 (95% CI, 0.87–0.94) in PSA >10.00 ng/ml (n = 409), respectively. In the cox model adjusted for age and baseline PSA level, for the detection rate of PCa, compared with PI-RADS 1–2 (reference), the hazard ratio was 6.43 (95% CI, 4.29–9.65) for PI-RADS 3, 18.58 (95% CI, 13.36–25.84) for PI-RADS 4–5 (p < 0.001).

Conclusions

Prebiopsy MP-MRI with PI-RADS is demonstrated as a valuable diagnostic and predictive tool for PCa.

Prostate-specific antigen-based prostate cancer screening: Past and future

Prostate-specific antigen-based prostate cancer screening remains a controversial topic. Up to now, there is worldwide consensus on the statement that the harms of population-based screening, mainly as a result of overdiagnosis (the detection of clinically insignificant tumors that would have never caused any symptoms), outweigh the benefits. However, worldwide opportunistic screening takes place on a wide scale. The European Randomized Study of Screening for Prostate Cancer showed a reduction in prostate cancer mortality through prostate-specific antigen based-screening. These population-based data need to be individualized in order to avoid screening in those who cannot benefit and start screening in those who will. For now, lacking a more optimal screening approach, screening should only be started after the process of shared decision-making. The focus of future research is the reduction of unnecessary testing and overdiagnosis by further research to better biomarkers and the value of the multiparametric magnetic resonance imaging, potentially combined in already existing prostate-specific antigen-based multivariate risk prediction models.

Focal therapy for prostate cancer: The current status

Purpose

In an era of increasing prostate cancer incidence and earlier detection, the assessment of clinical significance of prostate cancer is critical. Minimally invasive therapies are increasingly being investigated in localized prostate cancer.

Methods and results

In this review, we discuss the current status of magnetic resonance imaging targeted fusion prostate biopsy and focal therapy for prostate cancer, its rationale, and techniques.

Conclusion

Focal therapy offers a promising outlook for prostate cancer treatment, with the goal of effectively achieving cancer control while minimizing morbidity. Long term studies are needed.

Dynamic contrast enhanced MRI as a predictor of vascular-targeted photodynamic focal ablation therapy outcome in prostate cancer post-failed external beam radiation therapy

INTRODUCTION

Photodynamic therapy (PDT) can be employed as a focal therapy for prostate cancer. Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) can potentially help identify tumour recurrence after failed external-beam radiotherapy (EBRT). The purpose of this study was to determine the ability of DCE-MRI to predict early response to PDT salvage treatment.

METHODS

Patients with post-EBRT prostate cancer recurrence were prospectively enrolled into a Phase I/II trial of PDT using WST09. A 15-patient subgroup of this cohort undergoing 1.5T DCE-MRI at baseline and 1-week post-PDT was retrospectively analyzed. The reference standard was prostate biopsy obtained 6 months post-PDT. Analysis was performed on a patient-by-patient basis, by prostate gland halves, and by prostate sextants.

RESULTS

Biopsy 6 months post-PDT identified cancer in 10/15 patients (66.7%), and in 24/90 sextants (26.7%). Residual cancer was identified in 22/37 sextants (59.5%) identified as being involved at baseline. DCE-MRI at 1 week correctly predicted recurrent disease with a sensitivity of 100% (10/10), specificity of 60% (3/5), positive predictive value of 83.3% (10/12), negative predictive value of 100% (3/3), and an overall accuracy of 86.7%, (13/15). When analysis was performed on prostate halves, the sensitivity and negative predictive value remained at 100%, with an improvement in specificity to 88.2% (15/17). The overall accuracy of DCE-MRI was similar regardless of analysis method: 86.7% on a patient-by-patient basis, 86.7% by prostate half and 83.3% by sextant. Changes in prostate-specific antigen (PSA) did not correlate to response.

CONCLUSION

DCE-MRI shows promise as a tool to predict successful outcome when performed 1 week post-PDT and could potentially be used to inform the need for re-treatment at an early time-point.

Radical prostatectomy specimens - a voice against focal therapy

Introduction

The main treatment methods of prostate carcinoma are surgery and radiation therapy, both having serious side effects. Because of these side effects, the idea of organ preserving therapy emerged. Rationale to perform focal therapy is to preserve the prostate gland, along with potency and continence, offering good cancer control with appropriate treatment. The idea of gland sparing therapy is quite controversial. Presently, EAU Guidelines propose focal therapy as experimental in the treatment of prostate carcinoma.

Material and methods

The aim of the study was to asses how many patients could be qualified for focal therapy, according to post prostatectomy pathological findings. 720 patients suspected of prostate cancer were biopsied. In 324 patients, prostate carcinoma was revealed, of which 81 were subjected to radical prostatectomy. Pre and post–operative pathological results were analyzed, according to possible qualification for focal treatment.

Results

According to the clinical evaluation of all the patients referred to the treatment, 25% could be assumed to have unifocal disease and could be qualified to the focal treatment. Post–operative evaluation revealed pT2b cancer in 5%, pT2c disease in 65%, and pT3a–pT4a disease in 20% of these patients. Cancer was unilateral (pT2a–b) in only 15% of cases, and was suitable for focal treatment (small disease not extending to whole lobe– pT2a disease) in only 10%.

Conclusions

It seems that with the use of current methods, proper T–staging of the disease and amount of neoplasmatic tissue inside the gland can not be reached with great certainty. In our opinion, focal therapy should not be used in patients with ≤pT2b and high risk disease. For them, radical treatment (surgery or radiation therapy) should be recommended. For the rest of the patients, with low risk disease, keeping in mind the large scale of possible overtreatment, active surveillance is a valid treatment option. Focal therapy can be an interesting therapeutic proposition for a small group of patients with pT2a cancer, but it is not possible to select them with big certainty with current methods of imaging medicine.

Multiparametric magnetic resonance imaging of the prostate: technical aspects and role in clinical management

The heterogeneity and largely indolent nature of prostate cancer require better tools to avoid overdetection of low-risk disease and improve diagnostic accuracy in high-risk patients. During the last 3 decades, magnetic resonance imaging (MRI) has evolved to become the most accurate imaging technique for prostate cancer detection and staging, with a promising role in risk stratification. Because each MRI technique has advantages and limitations, state of the art of the so-called multiparametric MRI of the prostate is achieved combining anatomical T2-weighted imaging integrated with other techniques in which image contrast is related to the pathophysiology of the disease, such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. After reviewing this article, readers will understand the clinical challenges in the management of patients with confirmed or suspected prostate cancer, when and how multiparametric MRI of the prostate can provide meaningful information, and how to perform and interpret it.

Assessment of change in prostate volume and shape following surgical resection through co-registration of in-vivo MRI and fresh specimen ex-vivo MRI

AIM

To compare the size and shape of the prostate between in-vivo and fresh ex-vivo magnetic resonance imaging (MRI), in order to quantify alterations in the prostate resulting from surgical resection.

MATERIAL AND METHOD

Ten patients who had undergone 3 T prostate MRI using a phased-array coil and who were scheduled for prostatectomy were included in this prospective study. The ex-vivo specimen underwent MRI prior to formalin fixation or any other histopathological processing. Prostate volume in vivo and ex vivo was assessed using planimetry. Prostate shape was assessed by calculating ratios between the diameters of the prostate in all three dimensions.

RESULTS

Mean prostate volume was significantly smaller ex vivo than in vivo (39.7 ± 18.6 versus 50.8 ± 26.8 cm(3); p = 0.008), with an average change in volume of -19.5%. The right-to-left (RL)/anteroposterior (AP) ratio of the prostate, representing the shape of the prostate within its axial plane, was significantly larger ex vivo than in vivo (1.33 ± 0.14 versus 1.21 ± 0.12; p = 0.015), with an average percent change in RL/AP ratio of the prostate of +12.2%. There was no significant difference between in-vivo and ex-vivo acquisitions in terms of craniocaudal (CC)/AP (p = 0.963, median change = -2.1%) or RL/CC (p = 0.265, median change = +1.3%) ratios.

CONCLUSION

The observed volume and shape change following resection has not previously been assessed by comparison of in-vivo and fresh ex-vivo MRI and likely represents loss of vascularity and of connective tissue attachments in the ex-vivo state. These findings have implications for co-registration platforms under development to facilitate improved understanding of the accuracy of MRI in spatial localization of prostate tumours.

[Potential of PET/MRI for diagnosis of prostate cancer]

CLINICAL/METHODICAL ISSUE

A present goal is to improve detection and staging of prostate cancer using innovative imaging technology such as PET/MRI.

STANDARD RADIOLOGICAL METHODS

The modality of choice for detection of prostate cancer is multiparametric MRI. Furthermore, PET/CT is used, in particular, for the detection and staging of distant metastases and recurrent disease. For assessment of bone metastases, the method most commonly used is bone scintigraphy.

METHODICAL INNOVATIONS

The development of a simultaneous hybrid PET/MRI system is the last great "fusion" of the known cross-sectional image modalities. In addition, synthesis of new, innovative tracers such as (18)F-FACBC or (68)Ga-PSMA allows more specific detection of prostate cancer.

PERFORMANCE

Hybrid PET/MRI imaging has the potential to replace conventional imaging techniques in the future.

ACHIEVEMENTS

The method is just starting the broad application. Clinical studies must be expanded in order to substantiate the additional value of the method.

PRACTICAL RECOMMENDATIONS

Currently, there is still a low distribution situation, since it is a new and cost-intensive method. At the same time, there is still no consistent solution for reimbursement. The importance in practice first rises by clarifying the payment situation and further demonstration of the method's benefit by larger studies.

Prostate MRI: access to and current practice of prostate MRI in the United States

PURPOSE

MRI of the prostate has increasingly become more important in clinical medicine because of the risk of over-detection of low-grade, low-volume prostate cancer, as well as because of the poor sampling of transrectal ultrasound-guided prostate biopsy in high-risk patients. We sought to determine the access, imaging protocols, and indications for MRI imaging of the prostate in the United States.

METHODS

A brief survey was sent through mailing lists to members of the Society of Abdominal Radiology and Texas Radiological Society.

RESULTS

Thirty-six academic centers responded to the survey, 88.9% of which routinely perform prostate MRI. Nine centers routinely performed imaging at 1.5T with an endorectal coil (25%), 11 performed at 3.0T without an endorectal coil (31%), and 10 performed at 3.0T with an endorectal coil (28%). All institutions used T1-weighted axial and orthogonal T2-weighted sequences. Most groups used diffusion-weighted imaging (94.7%) and dynamic contrast enhancement (81.6%). Only 21.1% of groups performing prostate MRI routinely performed MR spectroscopy as part of their protocol.

CONCLUSIONS

Prostate MRI is becoming a commonly performed examination at academic institutions, with most locations performing prostate MRI at minimum standards. There is a need to educate nonacademic practices regarding the addition of functional MRI techniques to anatomic techniques, increase the number of institutions that regularly perform prostate MRI, and increase access to direct MRI-guided biopsy in institutions that perform prostate MRI on a regular basis.

Dosimetric effect of Elekta Beam modulator micromultileaf in three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for prostate cancer

The purpose of this study is to analyze the dosimetric effect of Elekta Beam Modulator in 3-dimensional conformal radiation therapy (3DCRT) and in intensity-modulated radiation therapy (IMRT) for localized prostate cancer. We compared treatment plans developed with 2 different Elekta multileaf collimators (MLC): Beam Modulator micro-MLC (mMLC) (4-mm leaf width at the isocenter) and standard MLC (10-mm leaf width at the isocenter). The comparison was performed for 15 patients with localized prostate cancer in 3DCRT and IMRT delivery; a total of 60 treatment plans were processed. The dose-volume histograms were used to provide the quantitative comparison between plans. In particular, we analyzed differences between rectum and bladder sparing in terms of a set of appropriate Vx (percentage of organ at risk [OAR] volume receiving the x dose) and differences between target conformity and coverage in terms of coverage factor and conformation number. Our analysis demonstrates that in 3DCRT there is an advantage in the use of Elekta Beam Modulator mMLC in terms of organ sparing; in particular, a significant decrease in rectal V60 and V50 (p = 0.001) and in bladder V70 and V65 (p = 0.007 and 0.002, respectively) was found. Moreover, a better target dose conformity was obtained (p = 0.002). IMRT plans comparison demonstrated no significant differences between the use of the 4 or 10-mm MLCs. Our analysis shows that in 3DCRT the use of the Elekta Beam Modulator mMLC gives a gain in target conformity and in OARs dose sparing whereas in IMRT plans there is no advantage.

Tumor target volume for focal therapy of prostate cancer-does multiparametric magnetic resonance imaging allow for a reliable estimation?

PURPOSE

We determined whether endorectal multiparametric magnetic resonance imaging at 1.5 Tesla could predict tumor target volume in the perspective of focal therapy of prostate cancer.

MATERIALS AND METHODS

A total of 84 consecutive patients underwent multiparametric magnetic resonance imaging before radical prostatectomy. The volume of each suspicious area detected on magnetic resonance imaging and of all surgical histological foci was determined by planimetry. We first used each magnetic resonance imaging sequence (T2-weighted, diffusion weighted and dynamic contrast enhanced) and then the sequence showing the largest tumor area (multiparametric volume). Finally, the largest area of any sequence was used to calculate a target volume according to the volume of a cylinder. Agreement between magnetic resonance imaging and pathological findings was assessed by linear regression and residual analysis.

RESULTS

Histology revealed 99 significant tumors with a volume of greater than 0.2 cc and/or a Gleason score of greater than 6. Of the tumors 16 (16.2%) were undetected by multiparametric magnetic resonance imaging. Linear regression analysis showed that tumor volume estimated by T2-weighted or diffusion weighted imaging correlated significantly with pathological volume (r(2) = 0.82 and 0.83, respectively). Residuals from diffusion weighted imaging volume estimations did not significantly differ from 0. Nevertheless, diffusion weighted imaging underestimated pathological volume in 43 of 87 cases (49%) by a mean of 0.56 cc (range 0.005 to 2.84). Multiparametric and target volumes significantly overestimated pathological volume by a mean of 16% and 44% with underestimation in 28 (32%) and 15 cases (17%), respectively. Volume underestimation was significantly higher for tumor foci less than 0.5 cc. The percent of Gleason grade 4 did not influence tumor volume estimation.

CONCLUSIONS

Magnetic resonance imaging can detect most significant tumors. However, delineating a target volume may require further adjustment before planning magnetic resonance imaging targeted focal treatment.

The PICTURE study -- prostate imaging (multi-parametric MRI and Prostate HistoScanning™) compared to transperineal ultrasound guided biopsy for significant prostate cancer risk evaluation

OBJECTIVE

The primary objective of the PICTURE study is to assess the negative predictive value of multi-parametric MRI (mp-MRI) and Prostate HistoScanning™ (PHS) in ruling-out clinically significant prostate cancer.

PATIENTS AND METHODS

PICTURE is a prospective diagnostic validating cohort study conforming to level 1 evidence. PICTURE will assess the diagnostic performance of multi-parametric Magnetic Resonance Imaging (mp-MRI) and Prostate HistoScanning™ (PHS) ultrasound. PICTURE will involve validating both index tests against a reference test, transperineal Template Prostate Mapping (TPM) biopsies, which can be applied in all men under evaluation. Men will be blinded to the index test results and both index tests will be reported prospectively prior to the biopsies being taken to ensure reporter blinding. Paired analysis of each of the index tests to the reference test will be done at patient level. Those men with an imaging lesion will undergo targeted biopsies to assess the clinical utility of sampling only suspicious areas. The study is powered to assess the negative predictive value of these imaging modalities in ruling-out clinically significant prostate cancer.

DISCUSSION

The PICTURE study aims to assess the performance characteristics of two imaging modalities (mp-MRI and Prostate HistoScanning) for their utility in the prostate cancer pathway. PICTURE aims to identify if either imaging test may be useful for ruling out clinically significant disease in men under investigation, and also to examine if either imaging modality is useful for the detection of disease. Recruitment is underway and expected to complete in 2014.

How will focal therapy fit in with existing treatments?

CONTEXT

The current management of localized prostate cancer is a therapeutic challenge with different options including active radicals or active follow-up. The aim of this paper is to analyze the feasibility and validity of the «Focal» active treatment versus the concept of active follow-up or Radical Treatment.

EVIDENCE ACQUISITION

We reviewed the literature on the various diagnostic methods, advantages, and difficulties of active follow-up and Radical Treatment, versus focal therapy with the possibilities of defining characteristics of aggressiveness and patient selection.

EVIDENCE SYNTHESIS

The mesh biopsy techniques along with multiparametric magnetic resonance imaging and association of factors such as tumor size, length of affected cylinder and Gleason are parameters that allow us to define location and definition of clinically significant tumors and subsidiary of focal therapies.

CONCLUSIONS

The definition, location and aggressiveness of prostate cancer in low-intermediate risk tumors can be defined avoiding radical therapies with their side effects or the risks of underestimating tumors as in active follow-up without the minimum side effects.

Parameters predicting postoperative unilateral disease in patients with unilateral prostate cancer in diagnostic biopsy: a rationale for selecting hemiablative focal therapy candidates

BACKGROUND

Focal hemiablative therapy for prostate cancer is a new treatment alternative. Unilateral and unifocal disease are its main limitations. The aim of this study was to identify the epidemiological, clinical and pathological parameters that may predict unilateral disease in patients diagnosed with prostate cancer.

METHODS

We performed a retrospective analysis of patients at our institution between January 2005 and January 2011. Only patients with unilateral disease in prostate biopsy were part of the study. The analysis included age, preoperative prostate-specific antigen (PSA) and its density, prostate volume, biopsy first and second Gleason pattern and Gleason summary, number of biopsy cores, percentage of cancer in biopsy material and the presence of high-grade prostatic intraepithelial neoplasia. Their role as potential predictors was evaluated by univariate and multivariate analysis.

RESULTS

A total of 161 patients had unilateral disease after prostate biopsy. A significant correlation was found between prostate volume, PSA density and percentage of cancer in biopsy material and the presence of unilateral disease in the surgical specimen. These are the same factors significant in the univariate analysis. The results of the multivariate analysis demonstrated that PSA density (p = 0.015) and percentage of cancer in biopsy material (p = 0.028) are the most significant predictors.

INTERPRETATION

Our results demonstrate that PSA density and the percentage of cancer in biopsy cores are significant predictors for prostate cancer unilaterality and should be considered for the selection of hemiablative focal therapy candidates.

Comparison of body-array MRI and Partin tables for predicting extracapsular prostate cancer

Objective:

The objective of this article is to evaluate the performance of magnetic resonance imaging (MRI) and Partin tables at predicting extracapsular disease (ECD) in men with prostate cancer.

Patients and methods:

We identified all patients who had a radical prostatectomy at our institution in 2008. MRI and Partin predictions of ECD were compared with the histopathological stage. Oncological outcome at one year was assessed by biochemical recurrence (BCR) (prostate-specific antigen (PSA) ≥ 0.4 ng/dl followed by another rise).

Results:

Staging and follow-up data were available for 69 of the 80 patients (86%) who had had radical prostatectomy. Thirty-five of 69 patients had a body-array MRI scan. MRI predicted ECD (≥ rT3) with a sensitivity of 41% and specificity of 69%. Partin tables (> 50% risk ECD) had a sensitivity of 81% and specificity of 54%. Of the 35 patients who had an MRI scan, 22 (63%) had ECD and nine (26%) had BCR. Of the 34 men who were not staged with an MRI, only 10 (29%) had ECD and four (12%) had BCR.

Conclusion:

MRI performed no better than Partin tables at predicting ECD. Furthermore, patients who did not have an MRI, because of favourable prognostic clinical variables, had a low risk of ECD and BCR. We question the role of body-array MRI for staging prostate cancer and recognise an urgent need for prospective evaluation of multiparametric MRI.

Accuracy of preoperative endo-rectal coil magnetic resonance imaging in detecting clinical under-staging of localized prostate cancer

OBJECTIVES

To assess the accuracy of intra-rectal coil magnetic resonance imaging (ER-MRI) for staging early prostate cancer (EPC).

MATERIALS AND METHODS

ER-MRI was performed with the Magnetom Symphony 1.5 Tesla system. ER-MRI and pathology findings were statistically correlated.

RESULTS

One hundred and fifty-four consecutive patients underwent radical prostatectomy (RRP) for EPC (cT1c-2 Nx M0). An average age was 66, mean PSA 11.04 µg/L (median 7.33 µg/L) and mean pathologic Gleason score 6. Pathology detected 97 out of 154 patients (63 %) as EPC and 57 cases (37 %) as extra-prostate extension (EPED) (pT3) with extra-capsular extension (ECE) (pT3a) in 41 (27 %) and seminal vesicle invasion (SVI) (pT3b) in 16 (10 %). ER-MRI staged 100 patients (65 %) as cT2 and 54 (35 %) as EPED with ECE in 37 cases (24 %) and SVI in 17 (11 %). ER-MRI sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy resulted respectively 0.78, 0.96, 0.86, 0.92, 0.91 for ECE as well as 0.88, 0.98, 0.82, 0.99 and 0.97 for SVI.

CONCLUSION

ER-MRI was effective in detecting preoperative EPC under-staging. In the next future, multi-parametric 3-Tesla ER-MRI will be the procedure for diagnosing, staging and following-up prostate cancer patients.

Validation of the European Society of Urogenital Radiology scoring system for prostate cancer diagnosis on multiparametric magnetic resonance imaging in a cohort of repeat biopsy patients

BACKGROUND

Wide variations in acquisition protocols and the lack of robust diagnostic criteria make magnetic resonance imaging (MRI) detection of prostate cancer (PCa) one of the most challenging fields in radiology and urology.

OBJECTIVE

To validate the recently proposed European Society of Urogenital Radiology (ESUR) scoring system for multiparametric MRI (mpMRI) of the prostate.

DESIGN, SETTING, AND PARTICIPANTS

An institutional review board-approved multicentric prospective study; 129 consecutive patients (1514 cores) referred for mpMRI after at least one set of negative biopsies.

INTERVENTION

Transfer of mpMRI-suspicious areas on three-dimensional (3D) transrectal ultrasound images by 3D elastic surface registration; random systematic and targeted cores followed by core-by-core analysis of pathology and mpMRI characteristics of the core locations. The ESUR scores were assigned after the procedure on annotated Digital Imaging and Communications in Medicine archives.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relationships between ESUR scores and biopsy results were assessed by the Mann-Whitney U test. The Yates correction and Pearson χ(2) tests evaluated the association between categorical variables. A teaching set was randomly drawn to construct the receiver operating characteristic curve of the ESUR score sum (ESUR-S). The threshold to recommend biopsy was obtained from the Youden J statistics and tested in the remaining validation set in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.

RESULTS AND LIMITATIONS

Higher T2-weighted, dynamic weighted imaging and dynamic contrast-enhanced ESUR scores were observed in areas yielding cancer-positive cores. The proportion of positive cores increased with the ESUR-S aggregated in five increments (ESUR-S 3-5: 2.9%; ESUR-S 6-8: 11.1%; ESUR-S 9-10: 38.2%; ESUR-S 11-12: 63.4%; and ESUR-S 13-15: 83.3%; p<0.0001). A threshold of ESUR-S ≥ 9 exhibited the following characteristics: sensitivity: 73.5%; specificity: 81.5%; positive predictive value: 38.2%; negative predictive value: 95.2%; and accuracy: 80.4%. Although the study was not designed to compare repeat biopsy strategies, more targeted cores than random systematic cores were found to be positive for cancer (36.3% compared with 4.9%, p<0.00001).

CONCLUSIONS

In the challenging situation of repeat biopsies, the ESUR scoring system was shown to provide clinically relevant stratification of the risk of showing PCa in a given location.