Concordance between Gleason scores of needle biopsies and radical prostatectomy specimens: a population-based study

Restriction spectrum imaging improves MRI-based prostate cancer detection

PURPOSE

To compare the diagnostic performance of restriction spectrum imaging (RSI), with that of conventional multi-parametric (MP) magnetic resonance imaging (MRI) for prostate cancer (PCa) detection in a blinded reader-based format.

METHODS

Three readers independently evaluated 100 patients (67 with proven PCa) who underwent MP-MRI and RSI within 6 months of systematic biopsy (N = 67; 23 with targeting performed) or prostatectomy (N = 33). Imaging was performed at 3 Tesla using a phased-array coil. Readers used a five-point scale estimating the likelihood of PCa present in each prostate sextant. Evaluation was performed in two separate sessions, first using conventional MP-MRI alone then immediately with MP-MRI and RSI in the same session. Four weeks later, another scoring session used RSI and T2-weighted imaging (T2WI) without conventional diffusion-weighted or dynamic contrast-enhanced imaging. Reader interpretations were then compared to prostatectomy data or biopsy results. Receiver operating characteristic curves were performed, with area under the curve (AUC) used to compare across groups.

RESULTS

MP-MRI with RSI achieved higher AUCs compared to MP-MRI alone for identifying high-grade (Gleason score greater than or equal to 4 + 3=7) PCa (0.78 vs. 0.70 at the sextant level; P < 0.001 and 0.85 vs. 0.79 at the hemigland level; P = 0.04). RSI and T2WI alone achieved AUCs similar to MP-MRI for high-grade PCa (0.71 vs. 0.70 at the sextant level). With hemigland analysis, high-grade disease results were similar when comparing RSI + T2WI with MP-MRI, although with greater AUCs compared to the sextant analysis (0.80 vs. 0.79).

CONCLUSION

Including RSI with MP-MRI improves PCa detection compared to MP-MRI alone, and RSI with T2WI achieves similar PCa detection as MP-MRI.

MR-targeted TRUS prostate biopsy using local reference augmentation: initial experience

Purpose

To evaluate MR-targeted TRUS prostate biopsy using a novel local reference augmentation method.

Patients and methods

Tracker-based MR–TRUS fusion was applied using local reference augmentation. In contrast to conventional whole gland fusion, local reference augmentation focuses the highest registration accuracy to the region surrounding the lesion to be biopsied. Pre-acquired multi-parametric MR images (mpMRI) were evaluated using PIRADS classification. T2-weighted MR images were imported on an ultrasound machine to allow for MR–TRUS fusion. Biopsies were targeted to the most suspicious lesion area identified on mpMRI. Each target was biopsied 1–5 times. For each biopsied lesion the diameter, PIRADS and Gleason scores, visibility during fusion, and representativeness were recorded.

Results

Included were 23 consecutive patients with 25 MR suspicious lesions, of which 11 patients had a previous negative TRUS-guided biopsy and 12 were biopsy naïve. The cancer detection rate was 64 % (Gleason score ≥6). Biopsy was negative (i.e., no Gleason score) in seven patients confirmed by follow-up in all of them (up to 18 months). After MR–TRUS fusion, 88 % of the lesions could be visualized on TRUS. The cancer detection rate increases with increasing lesion size, being 73 % for lesions larger than 10 mm.

Conclusion

Tracker-based MR–TRUS fusion biopsy with local reference augmentation is feasible, especially for lesions with an MR maximum diameter of at least 10 mm or PIRADS 5 lesions. If this is not the case, we recommend in-bore MR-guided biopsy.

Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors

PURPOSE

To compare histological outcomes in patients undergoing MRI-transrectal ultrasound fusion transperineal (MTTP) prostate biopsy and determine the incremental benefit of targeted cores.

METHODS

Seventy-six consecutive patients with 89 MRI-identified targets underwent MTTP biopsy. Separate targeted biopsies and background cores were obtained according to a standardized protocol. Target biopsies were considered of added diagnostic value if these cores showed a higher Gleason grade than non-targeted cores taken from the same sector (Group 1, n = 41). Conversely, where background cores demonstrated an equal or higher Gleason grade, target cores were considered to be non-beneficial (Group 2, n = 48).

RESULTS

There was no significant difference in age, PSA, prostate volume, time-to-biopsy, and number of cores obtained between the groups. A greater proportion of target cores were positive for cancer (158/228; 69.3 %) compared to background (344/1881; 18.38 %). The median target volume was 0.54 cm(3) for Group 1 (range 0.09-2.79 cm(3)) and 1.65 cm(3) for Group 2 (0.3-9.07 cm(3)), p < 0.001. The targets in Group 1 had statistically lower diameters for short and long axes, even after correction for gland size. The highest area under the receiver operating characteristic curve was demonstrated when a lesion cutoff value of 1.0 cm in short axis was applied, resulting in a sensitivity of 83.3 % and a specificity of 82.9 %.

CONCLUSIONS

When a combined systematic and targeted transperineal prostate biopsy is performed, there is limited benefit in acquiring additional cores from larger-volume targets with a short axis diameter >1.0 cm.

Biomechanical modeling constrained surface-based image registration for prostate MR guided TRUS biopsy

PURPOSE

Adding magnetic resonance (MR)-derived information to standard transrectal ultrasound (TRUS) images for guiding prostate biopsy is of substantial clinical interest. A tumor visible on MR images can be projected on ultrasound (US) by using MR-US registration. A common approach is to use surface-based registration. The authors hypothesize that biomechanical modeling will better control deformation inside the prostate than a regular nonrigid surface-based registration method. The authors developed a novel method by extending a nonrigid surface-based registration algorithm with biomechanical finite element (FE) modeling to better predict internal deformations of the prostate.

METHODS

Data were collected from ten patients and the MR and TRUS images were rigidly registered to anatomically align prostate orientations. The prostate was manually segmented in both images and corresponding surface meshes were generated. Next, a tetrahedral volume mesh was generated from the MR image. Prostate deformations due to the TRUS probe were simulated using the surface displacements as the boundary condition. A three-dimensional thin-plate spline deformation field was calculated by registering the mesh vertices. The target registration errors (TREs) of 35 reference landmarks determined by surface and volume mesh registrations were compared.

RESULTS

The median TRE of a surface-based registration with biomechanical regularization was 2.76 (0.81-7.96) mm. This was significantly different than the median TRE of 3.47 (1.05-7.80) mm for regular surface-based registration without biomechanical regularization.

CONCLUSIONS

Biomechanical FE modeling has the potential to improve the accuracy of multimodal prostate registration when comparing it to a regular nonrigid surface-based registration algorithm and can help to improve the effectiveness of MR guided TRUS biopsy procedures.

Stratification of the aggressiveness of prostate cancer using pre-biopsy multiparametric MRI (mpMRI)

Risk stratification, based on the Gleason score (GS) of a prostate biopsy, is an important decision-making tool in prostate cancer management. As low-grade disease may not need active intervention, the ability to identify aggressive cancers on imaging could limit the need for prostate biopsies. We assessed the ability of multiparametric MRI (mpMRI) in pre-biopsy risk stratification of men with prostate cancer. One hundred and twenty men suspected to have prostate cancer underwent mpMRI (diffusion MRI and MR spectroscopic imaging) prior to biopsy. Twenty-six had cancer and were stratified into three groups based on GS: low grade (GS ≤ 6), intermediate grade (GS = 7) and high grade (GS ≥ 8). A total of 910 regions of interest (ROIs) from the peripheral zone (PZ, range 25-45) were analyzed from these 26 patients. The metabolite ratio [citrate/(choline + creatine)] and apparent diffusion coefficient (ADC) of voxels were calculated for the PZ regions corresponding to the biopsy cores and compared with histology. The median metabolite ratios for low-grade, intermediate-grade and high-grade cancer were 0.29 (range: 0.16, 0.61), 0.17 (range: 0.13, 0.32) and 0.13 (range: 0.05, 0.23), respectively (p = 0.004). The corresponding mean ADCs (×10(-3) mm(2) /s) for low-grade, intermediate-grade and high-grade cancer were 0.99 ± 0.08, 0.86 ± 0.11 and 0.69 ± 0.12, respectively (p < 0.0001). The combined ADC and metabolite ratio model showed strong discriminatory ability to differentiate subjects with GS ≤ 6 from subjects with GS ≥ 7 with an area under the curve of 94%. These data indicate that pre-biopsy mpMRI may stratify PCa aggressiveness noninvasively. As the recent literature data suggest that men with GS ≤ 6 cancer may not need radical therapy, our data may help limit the need for biopsy and allow informed decision making for clinical intervention. Copyright © 2015 John Wiley & Sons, Ltd.

Detection of Significant Prostate Cancer According to Anatomical Areas of Sampling Cores Obtained with Transrectal Systematic 12-Core Biopsy

BACKGROUND

To analyze the diagnostic performance of 12-core biopsy in detecting significant prostate cancer (PCa).

PATIENTS AND METHODS

Thisstudy included 206 PCa patients who underwent transrectal 12-core biopsy followed by radical prostatectomy. Radical prostatectomy specimens were anatomically divided into 12 areas according to the sampling cores, and the existence of significant cancer, defined by a tumor volume > 0.5 ml, was investigated. The detection rate of significant cancer in each area was calculated as follows: the number of positive core biopsies/the number of areas containing significant cancer × 100.

RESULTS

The overall detection rate of significant cancer in all areas was 53.6%. The detection rate was significantly higher in the standard sextant cores than in the additional 6 cores in patients with prostate-specific antigen ≥ 10 ng/ml, clinical stage ≥ T2, or biopsy Gleason score ≥ 7, but not in those with prostate-specific antigen < 10 ng/ml, clinical stage T1c, or biopsy Gleason score ≤ 6.

CONCLUSIONS

Approximately half of the significant cancers were not accurately detected, and the detection rates in biopsy cores other than the sextant cores appeared to be significantly lower in PCa patients with aggressive features.

[Prostate cancer. Part 2: Review of the various tumor grading systems over the years 1966-2015 and future perspectives of the new grading of the International Society of Urological Pathology (ISUP)]

The continued development of methods in needle biopsies and radical prostatectomy for treatment of prostate cancer has given special emphasis to the question of the prognostic relevance of the various systems of grading. The classical purely histological grading system of Gleason has been modified several times in the past decades and cleared the way for a new grading system by the prognostic grading of Epstein. Assessment of the old and also modified combined histological and cytological grading of Mostofi, the World health Organization (WHO) and the urologic-pathological working group of prostate cancer in connection with the Gleason grading (combined Gleason-Helpap grading), has led to considerably improved rates of concordance between biopsy and radical prostatectomy and to improved estimations of prognosis beside its contribution to the development of a more practicable grading system for clinical use.

Reproducibility of Multiparametric Magnetic Resonance Imaging and Fusion Guided Prostate Biopsy: Multi-Institutional External Validation by a Propensity Score Matched Cohort

PURPOSE

As the adoption of magnetic resonance imaging/ultrasound fusion guided biopsy expands, the reproducibility of outcomes at expert centers becomes essential. We sought to validate the comprehensive NCI (National Cancer Institute) experience with multiparametric magnetic resonance imaging and fusion guided biopsy in an external, independent, matched cohort of patients.

MATERIALS AND METHODS

We compared 620 patients enrolled in a prospective trial comparing systematic biopsy to fusion guided biopsy at NCI to 310 who underwent a similar procedure at Long Island Jewish Medical Center. The propensity score, defined as the probability of being treated outside NCI, was calculated using the estimated logistic regression model. Patients from the hospital were matched 1:1 for age, prostate specific antigen, magnetic resonance imaging suspicion score and prior negative biopsies. Clinically significant disease was defined as Gleason 3 + 4 or greater.

RESULTS

Before matching we found differences between the cohorts in age, magnetic resonance imaging suspicion score (each p <0.001), the number of patients with prior negative biopsies (p = 0.01), and the overall cancer detection rate and the cancer detection rate by fusion guided biopsy (each p <0.001). No difference was found in the rates of upgrading by fusion guided biopsy (p = 0.28) or upgrading to clinically significant disease (p = 0.95). A statistically significant difference remained in the overall cancer detection rate and the rate by fusion guided biopsy after matching. On subgroup analysis we found a difference in the overall cancer detection rate and the rate by fusion guided biopsy (p <0.001 and 0.003) in patients with prior negative systematic biopsy but no difference in the 2 rates (p = 0.39 and 0.51, respectively) in biopsy naïve patients.

CONCLUSIONS

Improved detection of clinically significant cancer by magnetic resonance imaging and fusion guided biopsy is reproducible by an experienced multidisciplinary team consisting of dedicated radiologists and urologists.

Role of Magnetic Resonance Imaging in Prostate Cancer Screening: A Pilot Study Within the Göteborg Randomised Screening Trial

BACKGROUND

Magnetic resonance imaging (MRI) and targeted biopsies (TB) have shown potential to more accurately detect significant prostate cancer compared with prostate-specific antigen (PSA) and systematic biopsies (SB).

OBJECTIVE

To compare sequential screening (PSA+MRI) with conventional PSA screening.

DESIGN, SETTING, AND PARTICIPANTS

Of 384 attendees in the 10th screening round of the Göteborg randomised screening trial, 124 men, median age 69.5 yr, had a PSA of ≥ 1.8 ng/ml and underwent a prebiopsy MRI. Men with suspicious lesions on MRI and/or PSA ≥ 3.0ng/ml were referred for biopsy. SB was performed blinded to MRI results and TB was performed in men with tumour-suspicious findings on MRI. Three screening strategies were compared (PSA ≥ 3.0+SB; PSA ≥ 3.0+MRI+TB and PSA ≥ 1.8+MRI+TB).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cancer detection rates, sensitivity, and specificity were calculated per screening strategy and compared using McNemar's test.

RESULTS AND LIMITATIONS

In total, 28 cases of prostate cancer were detected, of which 20 were diagnosed in biopsy-naïve men. Both PSA ≥ 3.0+MRI and PSA ≥ 1.8+MRI significantly increased specificity compared with PSA ≥ 3.0+SB (0.92 and 0.79 vs 0.52; p<0.002 for both), while sensitivity was significantly higher for PSA ≥ 1.8+MRI compared with PSA ≥ 3.0+MRI (0.73 vs 0.46, p=0.008). The detection rate of significant cancer was higher with PSA ≥ 1.8+MRI compared with PSA ≥ 3.0+SB (5.9% vs 4.0%), while the detection rate of insignificant cancer was lowered by PSA ≥ 3.0+MRI (0.3% vs 1.2%). The primary limitation of this study is the small sample of men.

CONCLUSION

A screening strategy with a lowered PSA cut-off followed by TB in MRI-positive men seems to increase the detection of significant cancers while improving specificity. If replicated, these results may contribute to a paradigm shift in future screening.

PATIENT SUMMARY

Major concerns in prostate-specific antigen screening are overdiagnosis and underdiagnosis. We evaluated whether prostate magnetic resonance imaging could improve the balance of benefits to harm in prostate cancer screening screening, and we found a promising potential of using magnetic resonance imaging in addition to prostate-specific antigen.

3D surface-based registration of ultrasound and histology in prostate cancer imaging

Several transrectal ultrasound (TRUS)-based techniques aiming at accurate localization of prostate cancer are emerging to improve diagnostics or to assist with focal therapy. However, precise validation prior to introduction into clinical practice is required. Histopathology after radical prostatectomy provides an excellent ground truth, but needs accurate registration with imaging. In this work, a 3D, surface-based, elastic registration method was developed to fuse TRUS images with histopathologic results. To maximize the applicability in clinical practice, no auxiliary sensors or dedicated hardware were used for the registration. The mean registration errors, measured in vitro and in vivo, were 1.5±0.2 and 2.1±0.5mm, respectively.

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.

Pathological upgrading in prostate cancer patients eligible for active surveillance: Does prostate-specific antigen density matter?

Purpose

To evaluate prospectively the role of prostate-specific antigen (PSA) density in predicting Gleason score upgrading in prostate cancer patients eligible for active surveillance (T1/T2, biopsy Gleason score≤6, PSA≤10 ng/mL, and ≤2 positive biopsy cores).

Materials and Methods

Between January 2010 and November 2013, among patients who underwent greater than 10-core transrectal ultrasound-guided biopsy, 60 patients eligible for active surveillance underwent radical prostatectomy. By use of the modified Gleason criteria, the tumor grade of the surgical specimens was examined and compared with the biopsy results.

Results

Tumor upgrading occurred in 24 patients (40.0%). Extracapsular disease and positive surgical margins were found in 6 patients (10.0%) and 8 patients (17.30%), respectively. A statistically significant correlation between PSA density and postoperative upgrading was found (p=0.030); this was in contrast with the other studied parameters, which failed to reach significance, including PSA, prostate volume, number of biopsy cores, and number of positive cores. Tumor upgrading was also highly associated with extracapsular cancer extension (p=0.000). The estimated optimal cutoff value of PSA density was 0.13 ng/mL², obtained by receiver operating characteristic analysis (area under the curve=0.66; p=0.020; 95% confidence interval, 0.53-0.78).

Conclusions

PSA density is a strong predictor of Gleason score upgrading after radical prostatectomy in patients eligible for active surveillance. Because tumor upgrading increases the potential for postoperative pathological adverse findings and prognosis, PSA density should be considered when treating and consulting patients eligible for active surveillance.

Defining the learning curve for multiparametric magnetic resonance imaging (MRI) of the prostate using MRI-transrectal ultrasonography (TRUS) fusion-guided transperineal prostate biopsies as a validation tool

OBJECTIVES

To determine the accuracy of multiparametric magnetic resonance imaging (mpMRI) during the learning curve of radiologists using MRI targeted, transrectal ultrasonography (TRUS) guided transperineal fusion biopsy (MTTP) for validation.

PATIENTS AND METHODS

Prospective data on 340 men who underwent mpMRI (T2-weighted and diffusion-weighted MRI) followed by MTTP prostate biopsy, was collected according to Ginsburg Study Group and Standards for Reporting of Diagnostic Accuracy standards. MRI data were reported by two experienced radiologists and scored on a Likert scale. Biopsies were performed by consultant urologists not 'blinded' to the MRI result and men had both targeted and systematic sector biopsies, which were reviewed by a dedicated uropathologist. The cohorts were divided into groups representing five consecutive time intervals in the study. Sensitivity and specificity of positive MRI reports, prostate cancer detection by positive MRI, distribution of significant Gleason score and negative MRI with false negative for prostate cancer were calculated. Data were sequentially analysed and the learning curve was determined by comparing the first and last group.

RESULTS

We detected a positive mpMRI in 64 patients from Group A (91%) and 52 patients from Group E (74%). The prostate cancer detection rate on mpMRI increased from 42% (27/64) in Group A to 81% (42/52) in Group E (P < 0.001). The prostate cancer detection rate by targeted biopsy increased from 27% (17/64) in Group A to 63% (33/52) in Group E (P < 0.001). The negative predictive value of MRI for significant cancer (>Gleason 3+3) was 88.9% in Group E compared with 66.6% in Group A.

CONCLUSION

We demonstrate an improvement in detection of prostate cancer for MRI reporting over time, suggesting a learning curve for the technique. With an improved negative predictive value for significant cancer, decision for biopsy should be based on patient/surgeon factors and risk attributes alongside the MRI findings.

4-D spatiotemporal analysis of ultrasound contrast agent dispersion for prostate cancer localization: a feasibility study

Currently, nonradical treatment for prostate cancer is hampered by the lack of reliable diagnostics. Contrastultrasound dispersion imaging (CUDI) has recently shown great potential as a prostate cancer imaging technique. CUDI estimates the local dispersion of intravenously injected contrast agents, imaged by transrectal dynamic contrast-enhanced ultrasound (DCE-US), to detect angiogenic processes related to tumor growth. The best CUDI results have so far been obtained by similarity analysis of the contrast kinetics in neighboring pixels. To date, CUDI has been investigated in 2-D only. In this paper, an implementation of 3-D CUDI based on spatiotemporal similarity analysis of 4-D DCE-US is described. Different from 2-D methods, 3-D CUDI permits analysis of the entire prostate using a single injection of contrast agent. To perform 3-D CUDI, a new strategy was designed to estimate the similarity in the contrast kinetics at each voxel, and data processing steps were adjusted to the characteristics of 4-D DCE-US images. The technical feasibility of 4-D DCE-US in 3-D CUDI was assessed and confirmed. Additionally, in a preliminary validation in two patients, dispersion maps by 3-D CUDI were quantitatively compared with those by 2-D CUDI and with 12-core systematic biopsies with promising results.

Apparent diffusion coefficient value and ratio as noninvasive potential biomarkers to predict prostate cancer grading: comparison with prostate biopsy and radical prostatectomy specimen

OBJECTIVE. The purpose of this study is to test the association between diffusion-weighted MRI and prostate cancer Gleason score at both biopsy and final pathologic analysis after radical prostatectomy. SUBJECTS AND METHODS. Patients with prostate cancer (n = 72) underwent diffusion-weighted MRI (b values, 0, 800, and 1600 s/mm(2)) with an endorectal coil. Apparent diffusion coefficient (ADC) and ADC ratio were obtained in normal and pathologic tissue and were correlated with transrectal ultrasound-guided biopsy (n = 72) and histopathologic (n = 39) Gleason scores using the ANOVA test. ADC accuracy was estimated using ROC curves. RESULTS. Lesions suspicious for prostate cancer were detected in 65 patients. The mean ADC was 1.47 and 0.87 × 10(-3) mm(2)/s for normal and pathologic tissue, respectively (p < 0.001). When we divided the population into four groups (normal tissue and biopsy Gleason scores of 6, 7, and 8-10), then the mean ADC value was 1.47, 0.96, 0.80, and 0.78 × 10(-3) mm(2)/s, respectively (p < 0.001). The ADC ratio decreased along with an increase in biopsy Gleason score (66.9%, 56.7%, and 51.5% for Gleason scores of 6, 7 and 8-10, respectively) (ANOVA, p = 0.003) and pathologic Gleason score (ANOVA, p < 0.001). ROC curves had an AUC of 0.94 and 0.86 for ADC and ADC ratio, respectively (p = 0.012 and 0.042, respectively). CONCLUSION. Decreasing ADC values may represent a strong risk factor of harboring a poorly differentiated prostate cancer, independently of biopsy characteristics.

Results of central pathology review of prostatic biopsies in a contemporary series from a phase III, multicenter, randomized controlled trial (SHIP0804)

To investigate contemporary rates of variation in the biopsy Gleason grading in prostate cancer, between local and central pathologists, based on central review of the pathological slides from Seed and Hormone for Intermediate-risk Prostate Cancer (SHIP) 0804, a phase III, multicenter, randomized, controlled study. From April 2008 to May 2011, 18 Japanese institutions participated. All H&E slides were reviewed independently, without clinical information, and a tumor grade was assigned according to the modified Gleason grading system proposed by the International Society of Urological Pathology (ISUP). Prostate biopsy specimens of 642 cases were available for evaluation. An exact concordance rate of Gleason score (GS) between local and central pathologists was determined to be 65.3%; with the under-grading and over-grading of grades to be 14.6% and 20.1%, respectively. The central review resulted in numbers of tumor-bearing cores reassigned in 99 of 616 cases in which such information by the local pathologists was available (16.1%). Discordance in biopsy Gleason grading was still found in one third of the cases in the SHIP0804 study. This information is valuable in extrapolating the diagnostic error range in contemporary clinical studies conducted without central pathological review.

Magnetic resonance imaging-guided prostate biopsy: present and future

Systemic transrectal ultrasound-guided biopsy (TRUSBx) is the standard procedure for diagnosing prostate cancer (PCa), but reveals a limited accuracy for the detection of cancer. Currently, multiparametric MR imaging (mp-MRI) is increasingly regarded as a promising method to detect PCa with an excellent positive predictive value. The use of mp-MRI during a MRI-guided biopsy (MRGB) procedure improves the quality of a targeted biopsy. The aim of this article is to provide an overview about the MRGB technique for PCa detection, to review the accuracy and clinical indications of MRGB and discuss its current issues and further directions. A MRGB seems accurate and efficient for the detection of clinically significant PCa in men with previous negative TRUSBx. Moreover, it may decrease the detection of clinically insignificant cancers with fewer biopsy cores.

Conditional probability of reclassification in an active surveillance program for prostate cancer

PURPOSE

We evaluated the risk of prostate cancer reclassification by time on active surveillance.

MATERIALS AND METHODS

From 1995 to 2014 we evaluated 557 and 251 men at very low and at low risk, respectively, who were on active surveillance and compliant with prostate biopsies. Our primary study outcome was reclassification to higher risk disease by grade or extent. Freedom from reclassification was estimated using the Kaplan-Meier approach with adjustment for covariates using the Cox proportional hazards model.

RESULTS

Within the first 2 years of surveillance patient survival free of reclassification by grade (p = 0.20) and by any biopsy criteria (p = 0.25) was similar in men with very low and low risk disease. After 2 years men with low risk disease were 2.4 times more likely to be diagnosed with a Gleason score of greater than 6 than men with very low risk disease (p = 0.002, HR 2.4, 95% CI 1.9-3.5). Additionally, beyond 2 years on surveillance the risk of lifetime reclassification by grade and by any criteria decreased by 30% and 35% (each p <0.0001, HR 0.70, 95% CI 0.60-0.76 and HR 0.65, 95% CI 0.57-0.72, respectively) with each biopsy that showed no reclassification.

CONCLUSIONS

The reclassification rate during surveillance is not equally distributed across time or risk groups. Due to misclassification at diagnosis the reclassification rate in very low and low risk groups is similar in the first 2 years but differs significantly beyond 2 years. The risk of reclassification decreases with time for each nonreclassifying biopsy beyond 2 years.

Correlation of gleason scores with magnetic resonance diffusion tensor imaging in peripheral zone prostate cancer

BACKGROUND

To investigate tumor aggressiveness in peripheral zone prostate cancer (PCa) by correlating Gleason score (GS) with diffusion tensor imaging (DTI) from multiparametric magnetic resonance imaging (MRI) at 3.0 Tesla (T).

METHODS

Eighty-three patients with pathological proven peripheral zone PCa whose GS in at least one core biopsy met the criteria(GS ≤3+3, GS 3+4, GS 4+3, or GS ≥4+4) were included in this study. DTI was performed using b values of 0 and 800 s/mm(2) with 32 directions in all patients on a 3.0T MRI scanner. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from the DTI data of patients with the previously mentioned four categories of Gleason scores. An association between DTI measurements(FA, ADC) and GS was tested using the Spearman rank correlation analysis.

RESULTS

FA values in the sextants found to harbor cancer were positively correlated with the GS(r = 0.48; P < 0.001), while the ADC values were negatively correlated with GS(r = -0.54; P < 0.001). Statistical significance(P < 0.05) was found for FA values among different GS groups, with the exception of GS 3+4 versus GS 4+3 (P = 0.105). The differences between the ADC values were statistically significant for all four different scores(all P < 0.05).

CONCLUSION

Quantitative DTI at 3.0T MRI shows a significant association with GS in the evaluation of tumor aggressiveness in peripheral zone PCa, which may be useful to ensure concordance of biopsy results and therefore make the appropriate decision in the management of patients with PCa.

Upgrading and upstaging in prostate cancer: From prostate biopsy to radical prostatectomy

Prostate cancer (CaP) is the most common malignancy in men and the second cause of cancer-related mortality after lung cancer. Several studies have evaluated the correlation between bioptic and pathological Gleason score (GS), documenting a correlation ranging between 30 and 60%. The aim of this study was the evaluation of the association between bioptic and pathological GS in a series of patients undergoing prostate needle biopsy and subsequent radical prostatectomy. We also aimed to evaluate the possible prognostic factors of upgrading and upstaging. We prospectively collected and retrospectively reviewed data from 300 consecutive patients who underwent radical retropubic or robot-assisted prostatectomy at our Institution. Patients who underwent prostate needle biopsy, transrectal or transperineal, with a minimum of 5 samples, were included in this study. Upgrading and downgrading were defined as increase or decrease, respectively, from one prognostic grade group to another, similar to up- or downstaging. The mean age of the patients was 62.97 years and the mean prostate-spesific antigen (PSA) level was 7.83 ng/ml. A total of 51.3% of the population underwent a transperineal prostate biopsy. The most frequently represented bioptic GS was 3+3 (64.0%) followed by 3+4=7 (15.6%); the most frequent pathological Gleason score was 3+4 (44.3%), followed by 3+3 (31.0%). With reagard to the bioptic GS 4-5-6 group, approximately half of the specimens (46.7%) were subsequently upgraded to GS 3+4, and 5.3% to 4+3. With regards to the bioptic GS 3+4 group, 57.4% was confirmed in the surgical specimen. In the 4+3 group, 23.5% of the cases was downgraded to 3+4 and 35.3% was confirmed. With regards to stage, ~39.7% of the patients received an upstaging on the pathological specimen. We evaluated the correlations between preoperative serum PSA level, prostate volume, digital rectal examination and biopsy type and none of the variables considered exhibited a correlation with any upgrading (P>0.05). Moreover, we evaluated the correlations between the aforementioned variables and upstaging and, at the multivariate analysis, only a serum PSA <4 ng/ml was found to be an independent variable predictive of upstaging (P=0.017). Therefore, new tools are required to predict upgrading and upstaging of our patients, in order to ensure better counseling for optimal treatment planning.

Identification of proteomic biomarkers predicting prostate cancer aggressiveness and lethality despite biopsy-sampling error

Background:

Key challenges of biopsy-based determination of prostate cancer aggressiveness include tumour heterogeneity, biopsy-sampling error, and variations in biopsy interpretation. The resulting uncertainty in risk assessment leads to significant overtreatment, with associated costs and morbidity. We developed a performance-based strategy to identify protein biomarkers predictive of prostate cancer aggressiveness and lethality regardless of biopsy-sampling variation.

Methods:

Prostatectomy samples from a large patient cohort with long follow-up were blindly assessed by expert pathologists who identified the tissue regions with the highest and lowest Gleason grade from each patient. To simulate biopsy-sampling error, a core from a high- and a low-Gleason area from each patient sample was used to generate a ‘high' and a ‘low' tumour microarray, respectively.

Results:

Using a quantitative proteomics approach, we identified from 160 candidates 12 biomarkers that predicted prostate cancer aggressiveness (surgical Gleason and TNM stage) and lethal outcome robustly in both high- and low-Gleason areas. Conversely, a previously reported lethal outcome-predictive marker signature for prostatectomy tissue was unable to perform under circumstances of maximal sampling error.

Conclusions:

Our results have important implications for cancer biomarker discovery in general and development of a sampling error-resistant clinical biopsy test for prediction of prostate cancer aggressiveness.

TRUS-MRI image registration: a paradigm shift in the diagnosis of significant prostate cancer

Accuracy of multiparametric MRI has greatly improved the ability of localizing tumor foci of prostate cancer. This property can be used to perform a TRUS-MR image registration, new technological advance, which allows for an overlay of an MRI onto a TRUS image to target a prostate biopsy toward a suspicious area Three types of registration have been developed: cognitive-based, sensor-based, and organ-based registration. Cognitive registration consists of aiming a suspicious area during biopsy with the knowledge of the lesion location identified on multiparametric MRI. Sensor-based registration consists of tracking in real time the TRUS probe with a magnetic device, achieving a global positioning system which overlays in real-time prostate image on both modalities. Its main limitation is that it does not take into account prostate and patient motion during biopsy. Two systems (Artemis and Uronav) have been developed to partially circumvent this drawback. Organ-based registration (Koelis) does not aim to track the TRUS probe, but the prostate itself to compute in a 3D acquisition the TRUS prostate shape, allowing for a registration with the corresponding 3D MRI shape. This system is not limited by prostate/patient motion and allows for a deformation of the organ during registration. Pros and cons of each technique and the rationale for a targeted biopsy only policy are discussed.

Notch signaling in prostate cancer: a moving target

INTRODUCTION

By regulating cell fate, proliferation, and survival, Notch pathway signaling provides critical input into differentiation, organization, and function of multiple tissues. Notch signaling is also becoming an increasingly recognized feature in malignancy, including prostate cancer, where it may play oncogenic or tumor suppressive roles.

METHODS

Based on an electronic literature search from 2000 to 2013 we identified, summarized, and integrated published research on Notch signaling dynamics in prostate homeostasis and prostate cancer.

RESULTS

In benign prostate, Notch controls the differentiation state and architecture of the gland. In prostate cancer, similar features correlate with lethal potential and may be influenced by Notch. Increased Notch1 can confer a survival advantage on prostate cancer cells, and levels of Notch family members, such as Jagged2, Notch3, and Hes6 increase with higher cancer grade. However, Notch signaling can also antagonize growth and survival of both benign and malignant prostate cells, possibly through antagonistic effects of the Notch target HEY1 on androgen receptor function.

DISCUSSION

Notch signaling can dramatically influence prostate development and disease. Determining the cellular contexts where Notch promotes or suppresses prostate growth could open opportunities for diagnostic and therapeutic interventions.

High b value (2,000 s/mm2) diffusion-weighted magnetic resonance imaging in prostate cancer at 3 Tesla: comparison with 1,000 s/mm2 for tumor conspicuity and discrimination of aggressiveness

Objective

The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T.

Materials and Methods

The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm² and 0, 2000 s/mm²) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10⁻³ mm²/s) of the tumor regions and normal regions were measured.

Results

Mean LCS and TNR at 0, 2000 s/mm² was significantly higher than those at 0, 1000 s/mm² (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm² was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm² (ρ = −0.602; p<0.001) and 0, 2000 s/mm² (ρ = −0.645; p<0.001).

Conclusions

For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm² is more useful than b = 0, 1000 s/mm².

When is prostate cancer really cancer?

Several investigators have challenged the idea that low-grade cancers are a cause for concern, suggesting that the term cancer should not be applied to these tumors. This article reviews the defining features of cancer, and the diagnostic and prognostic classification systems currently used for prostate cancer. Logical, morphologic, and molecular evidence is presented to show that low-grade prostate cancers are correctly classified as cancer. The authors suggest, however, that 6 out of 10 on an aggressiveness scale is inappropriate for indolent cancer, and that a proposed reinterpretation of Gleason grading categories is a more logical way to address overtreatment.

Cost-effectiveness of magnetic resonance (MR) imaging and MR-guided targeted biopsy versus systematic transrectal ultrasound-guided biopsy in diagnosing prostate cancer: a modelling study from a health care perspective

BACKGROUND

The current diagnostic strategy using transrectal ultrasound-guided biopsy (TRUSGB) raises concerns regarding overdiagnosis and overtreatment of prostate cancer (PCa). Interest in integrating multiparametric magnetic resonance imaging (MRI) and magnetic resonance-guided biopsy (MRGB) into the diagnostic pathway to reduce overdiagnosis and improve grading is gaining ground, but it remains uncertain whether this image-based strategy is cost-effective.

OBJECTIVE

To determine the cost-effectiveness of multiparametric MRI and MRGB compared with TRUSGB.

DESIGN, SETTING, AND PARTICIPANTS

A combined decision tree and Markov model for men with elevated prostate-specific antigen (>4 ng/ml) was developed. Input data were derived from systematic literature searches, meta-analyses, and expert opinion.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Quality-adjusted life years (QALYs) and health care costs of both strategies were modelled over 10 yr after initial suspicion of PCa. Probabilistic and threshold analyses were performed to assess uncertainty.

RESULTS AND LIMITATIONS

Despite uncertainty around the presented cost-effectiveness estimates, our results suggest that the MRI strategy is cost-effective compared with the standard of care. Expected costs per patient were € 2423 for the MRI strategy and € 2392 for the TRUSGB strategy. Corresponding QALYs were higher for the MRI strategy (7.00 versus 6.90), resulting in an incremental cost-effectiveness ratio of € 323 per QALY. Threshold analysis revealed that MRI is cost-effective when sensitivity of MRGB is ≥ 20%. The probability that the MRI strategy is cost-effective is around 80% at willingness to pay thresholds higher than € 2000 per QALY.

CONCLUSIONS

Total costs of the MRI strategy are almost equal with the standard of care, while reduction of overdiagnosis and overtreatment with the MRI strategy leads to an improvement in quality of life.

PATIENT SUMMARY

We compared costs and quality of life (QoL) of the standard "blind" diagnostic technique with an image-based technique for men with suspicion of prostate cancer. Our results suggest that costs were comparable, with higher QoL for the image-based technique.

Concordance Between Prostate Needle Biopsy and Surgical Histopathology in a Primarily African-American Population

Introduction. Prior studies have revealed that the concordance between biopsy and surgical specimens has been improving over time. However, to date, this has not been analyzed in an African American population, for whom data have often shown more aggressive prostate cancer than for other races. Methods. We analyzed 250 patients who were operated on at the NY Harbor Department of Veterans Affairs for localized prostate cancer between 2003 and 2010. The clinical biopsy scores were compared with the pathological biopsy scores. We compared the concordance using the κ coefficient. Univariate and multivariate logistic regressions were used to identify predictors for poor concordance. Results. This population consisted of 59.6% African Americans, 32% Caucasians, and 8.4% Hispanics. Overall, there was a 50% exact concordance between the biopsy and surgical specimens. The κ was 0.33, indicating fair agreement. Patients with a Gleason score of 6 were found to have an exact concordance 66% of the time, and those with a score of Gleason 7 (3 + 4) had an exact concordance 50% of the time. On univariate and multivariate analyses, only an increasing prostate-specific antigen was associated with reduced concordance. Race was not a significant predictor. Conclusions. These data are in line with prior studies of concordance. Despite being a population with more aggressive prostate cancer, there does not appear to be an increase in the risk of discordance in African American men.

The role of PSA density to predict a pathological tumour upgrade between needle biopsy and radical prostatectomy for low risk clinical prostate cancer in the modified Gleason system era

OBJECTIVES

We evaluate the role of prostate-specific antigen (PSA) density to predict Gleason score upgrade between prostate biopsy material and radical prostatectomy specimen examination in patients with low-risk prostate cancer.

METHODS

Between January 2007 and November 2011, 133 low-risk patients underwent a radical prostatectomy. Using the modified Gleason criteria, tumour grade of the surgical specimens was examined and compared to the biopsy results.

RESULTS

A tumour upgrade was noticed in 57 (42.9%) patients. Organ-confined disease was found in 110 (82.7%) patients, while extracapsular disease and seminal vesicles invasion was found in 19 (14.3%) and 4 (3.0%) patients, respectively. Positive surgical margins were reported in 23 (17.3%) patients. A statistical significant correlation between the preoperative PSA density value and postoperative upgrade was found (p = 0.001) and this observation had a predictive value (p = 0.002); this is in contrast to the other studied parameters which failed to reach significance, including PSA, percentage of cancer in biopsy and number of biopsy cores. Tumour upgrade was also highly associated with extracapsular cancer extension (p = 0.017) and the presence of positive surgical margins (p = 0.017).

CONCLUSIONS

PSA density represents a strong predictor for Gleason score upgrade after radical prostatectomy in patients with clinical low-risk disease. Since tumour upgrade increases the potential for postoperative pathological adverse findings and prognosis, PSA density should be considered when treating and consulting patients with low-risk prostate cancer.

Clinical utility of endorectal MRI-guided prostate biopsy: preliminary experience

PURPOSE

To investigate the potential clinical utility of endorectal MRI-guided biopsy in patients with known or suspected prostate cancer.

MATERIALS AND METHODS

We prospectively recruited 24 men with known or suspected prostate cancer in whom MRI-guided biopsy was clinically requested after multiparametric endorectal MRI showed one or more appropriate targets. One to six 18-gauge biopsy cores were obtained from each patient. Transrectal ultrasound guided biopsy results and post MRI-guided biopsy complications were also recorded.

RESULTS

MRI-guided biopsy was positive in 5 of 7 patients with suspected prostate cancer (including 2 of 4 with prior negative ultrasound-guided biopsies), in 8 of 12 with known untreated prostate cancer (including 5 where MRI-guided biopsy demonstrated a higher Gleason score than ultrasound guided biopsy results), and in 3 of 5 with treated cancer. MRI-guided biopsies had a significantly higher maximum percentage of cancer in positive cores when compared with ultrasound guided biopsy (mean of 37 ± 8% versus 13 ± 4%; P = 0.01). No serious postbiopsy complications occurred.

CONCLUSION

Our preliminary experience suggests endorectal MRI-guided biopsy may safely contribute to the management of patients with known or suspected prostate cancer by making a new diagnosis of malignancy, upgrading previously diagnosed disease, or diagnosing local recurrence.

Higher prostate weight is inversely associated with Gleason score upgrading in radical prostatectomy specimens

Background. Protective factors against Gleason upgrading and its impact on outcomes after surgery warrant better definition. Patients and Methods. Consecutive 343 patients were categorized at biopsy (BGS) and prostatectomy (PGS) as Gleason score, ≤6, 7, and ≥8; 94 patients (27.4%) had PSA recurrence, mean followup 80.2 months (median 99). Independent predictors of Gleason upgrading (logistic regression) and disease-free survival (DFS) (Kaplan-Meier, log-rank) were determined. Results. Gleason discordance was 45.7% (37.32% upgrading and 8.45% downgrading). Upgrading risk decreased by 2.4% for each 1 g of prostate weight increment, while it increased by 10.2% for every 1 ng/mL of PSA, 72.0% for every 0.1 unity of PSA density and was 21 times higher for those with BGS 7. Gleason upgrading showed increased clinical stage (P = 0.019), higher tumor extent (P = 0.009), extraprostatic extension (P = 0.04), positive surgical margins (P < 0.001), seminal vesicle invasion (P = 0.003), less “insignificant” tumors (P < 0.001), and also worse DFS, χ² = 4.28, df = 1, P = 0.039. However, when setting the final Gleason score (BGS ≤6 to PGS 7 versus BGS 7 to PGS 7), avoiding allocation bias, DFS impact is not confirmed, χ² = 0.40, df = 1, P = 0.530.Conclusions. Gleason upgrading is substantial and confers worse outcomes. Prostate weight is inversely related to upgrading and its protective effect warrants further evaluation.

Can delayed time to referral to a tertiary level urologist with an abnormal PSA level affect subsequent Gleason grade in the opportunistically screened population?

PURPOSE

There is growing conflict in the literature describing the effect of delayed treatment on outcomes following radical prostatectomy. There is also evidence to suggest progression of low-risk prostate cancer to develop higher grades and volumes of prostate cancer during active surveillance. It is unknown as to what affect a delay in referral of those men with abnormal screened-PSA levels have on subsequent Gleason grade.

METHODS

We identified 350 men through our rapid access prostate clinic who underwent TRUS biopsy for abnormal age-related PSA and/or abnormal clinical examination. Clinicopathological findings were compared for those with positive versus negative TRUS biopsies, and for those with initial delays in referral (<12 months, 12-18 months, and >18 months). We used ANOVA and Student's t-tests amongst other statistical tools to examine significance of clinical findings.

RESULTS

Of the 350 men who underwent TRUS biopsy, those with a delay in referral of 12 months or more were significantly associated with higher PSA titers, clinically palpable disease and likelihood of diagnosis with prostate cancer. A delay of 18 months or more led to a significantly higher risk of being diagnosed with a leading grade 4 prostate cancer, which was further supported using PSA velocity as a diagnostic tool (change >0.4 ng/ml/year).

CONCLUSION

We recommend that repeated asymptomatic abnormal age-related PSA readings and/or abnormal clinical examination in the screened population be referred without delay to a urologist for further assessment, enrolment into an active surveillance program or definitive subsequent treatment.

Prognostic value of preoperative multiparametric magnetic resonance imaging (MRI) for predicting biochemical recurrence after radical prostatectomy

OBJECTIVE

To evaluate the suitability of preoperative multiparametric magnetic resonance imaging (MRI) positivity as a predictor of biochemical recurrence after radical prostatectomy (RP).

PATIENTS AND METHODS

We reviewed the clinical records of patients who underwent either standard RP or laparoscopic RP between January 2005 and December 2009 at our institution. Patients who received radiotherapy or androgen deprivation therapy before surgery were excluded. A total of 314 patients met the study inclusion criteria. Cox proportional hazard regression models were used for analyses. In accordance with the criteria in the established guidelines, a radiologist scored the probability of the presence of prostate cancer using a five-point scale of diagnostic confidence level. The highest confidence level of any pulse sequence was considered as the evaluation result.

RESULTS

MRI positivity was significantly associated with a high clinical stage (cT ≥ 2; P = 0.039), a high positive biopsy core rate (≥0.2; P < 0.001), a high biopsy Gleason score ([GS] ≥8; P < 0.001) and a high pathological GS (≥8; P = 0.005). Univariate analysis and multivariate analysis showed that MRI positivity was a prognostic indicator in the analysis that included only preoperative variables and also in the analysis including preoperative and pathological variables.

CONCLUSION

Multiparametric MRI positivity can independently predict biochemical recurrence after RP.

Importance of prostate-specific antigen (PSA) as a predictive factor for concordance between the Gleason scores of prostate biopsies and RADICAL prostatectomy specimens

OBJECTIVE

To evaluate the concordance between the Gleason scores of prostate biopsies and radical prostatectomy specimens, thereby highlighting the importance of the prostate-specific antigen (PSA) level as a predictive factor of concordance.

METHODS

We retrospectively analyzed 253 radical prostatectomy cases performed between 2006 and 2011. The patients were divided into 4 groups for the data analysis and dichotomized according to the preoperative PSA, <10 ng/mL and ≥10 ng/mL. A p-score <0.05 was considered significant.

RESULTS

The average patient age was 63.3±7.8 years. The median PSA level was 9.3±4.9 ng/mL. The overall concordance between the Gleason scores was 52%. Patients presented preoperative PSA levels <10 ng/mL in 153 of 235 cases (65%) and ≥10 ng/mL in 82 of 235 cases (35%). The Gleason scores were identical in 86 of 153 cases (56%) in the <10 ng/mL group and 36 of 82 (44%) cases in the ≥10 ng/mL group (p=0.017). The biopsy underestimated the Gleason score in 45 (30%) patients in the <10 ng/mL group and 38 (46%) patients in the ≥10 ng/mL (p=0.243). Specifically, the patients with Gleason 3 + 3 scores according to the biopsies demonstrated global concordance in 56 of 110 cases (51%). In this group, the patients with preoperative PSA levels <10 ng/dL had higher concordance than those with preoperative PSA levels ≥10 ng/dL (61% x 23%, p=0.023), which resulted in 77% upgrading after surgery in those patients with PSA levels ≥10 ng/dl.

CONCLUSION

The Gleason scores of needle prostate biopsies and those of the surgical specimens were concordant in approximately half of the global sample. The preoperative PSA level was a strong predictor of discrepancy and might improve the identification of those patients who tended to be upgraded after surgery, particularly in patients with Gleason scores of 3 + 3 in the prostate biopsy and preoperative PSA levels ≥10 ng/mL.

Assessment of prostate cancer aggressiveness using dynamic contrast-enhanced magnetic resonance imaging at 3 T

BACKGROUND

A challenge in the diagnosis of prostate cancer (PCa) is the accurate assessment of aggressiveness.

OBJECTIVE

To validate the performance of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate at 3 tesla (T) for the assessment of PCa aggressiveness, with prostatectomy specimens as the reference standard.

DESIGN, SETTINGS, AND PARTICIPANTS

A total of 45 patients with PCa scheduled for prostatectomy were included. This study was approved by the institutional review board; the need for informed consent was waived.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Subjects underwent a clinical MRI protocol including DCE-MRI. Blinded to DCE-images, PCa was indicated on T2-weighted images based on histopathology results from prostatectomy specimens with the use of anatomical landmarks for the precise localization of the tumor. PCa was classified as low-, intermediate-, or high-grade, according to Gleason score. DCE-images were used as an overlay on T2-weighted images; mean and quartile values from semi-quantitative and pharmacokinetic model parameters were extracted per tumor region. Statistical analysis included Spearman's ρ, the Kruskal-Wallis test, and a receiver operating characteristics (ROC) analysis.

RESULTS AND LIMITATIONS

Significant differences were seen for the mean and 75th percentile (p75) values of wash-in (p = 0.024 and p = 0.017, respectively), mean wash-out (p = 0.044), and p75 of transfer constant (K(trans)) (p = 0.035), all between low-grade and high-grade PCa in the peripheral zone. ROC analysis revealed the best discriminating performance between low-grade versus intermediate-grade plus high-grade PCa in the peripheral zone for p75 of wash-in, K(trans), and rate constant (Kep) (area under the curve: 0.72). Due to a limited number of tumors in the transition zone, a definitive conclusion for this region of the prostate could not be drawn.

CONCLUSIONS

Quantitative parameters (K(trans) and Kep) and semi-quantitative parameters (wash-in and wash-out) derived from DCE-MRI at 3 T have the potential to assess the aggressiveness of PCa in the peripheral zone. P75 of wash-in, K(trans), and Kep offer the best possibility to discriminate low-grade from intermediate-grade plus high-grade PCa.

Utility of multiparametric magnetic resonance imaging suspicion levels for detecting prostate cancer

PURPOSE

We determine the usefulness of multiparametric magnetic resonance imaging in detecting prostate cancer, with a specific focus on detecting higher grade prostate cancer.

MATERIALS AND METHODS

Prospectively 583 patients who underwent multiparametric magnetic resonance imaging and subsequent prostate biopsy at a single institution were evaluated. On multiparametric magnetic resonance imaging, lesions were identified and scored as low, moderate or high suspicion for prostate cancer based on a validated scoring system. Magnetic resonance/ultrasound fusion guided biopsies of magnetic resonance imaging lesions in addition to systematic 12-core biopsies were performed. Correlations between the highest assigned multiparametric magnetic resonance imaging suspicion score and presence of cancer and biopsy Gleason score on the first fusion biopsy session were assessed using univariate and multivariate logistic regression models. Sensitivity, specificity, negative predictive value and positive predictive value were calculated and ROC curves were developed to assess the discriminative ability of multiparametric magnetic resonance imaging as a diagnostic tool for various biopsy Gleason score cohorts.

RESULTS

Significant correlations were found between age, prostate specific antigen, prostate volume, and multiparametric magnetic resonance imaging suspicion score and the presence of prostate cancer (p<0.0001). On multivariate analyses controlling for age, prostate specific antigen and prostate volume, increasing multiparametric magnetic resonance imaging suspicion was an independent prognosticator of prostate cancer detection (OR 2.2, p<0.0001). Also, incremental increases in multiparametric magnetic resonance imaging suspicion score demonstrated stronger associations with cancer detection in patients with Gleason 7 or greater (OR 3.3, p<0.001) and Gleason 8 or greater (OR 4.2, p<0.0001) prostate cancer. Assessing multiparametric magnetic resonance imaging as a diagnostic tool for all prostate cancer, biopsy Gleason score 7 or greater, and biopsy Gleason score 8 or greater separately via ROC analyses demonstrated increasing accuracy of multiparametric magnetic resonance imaging for higher grade disease (AUC 0.64, 0.69, and 0.72, respectively).

CONCLUSIONS

Multiparametric magnetic resonance imaging is a clinically useful modality to detect and characterize prostate cancer, particularly in men with higher grade disease.

Importance and determinants of Gleason score undergrading on biopsy sample of prostate cancer in a population-based study

Background

In this population-based study, we investigated the degree of concordance between Gleason scores obtained from prostate biopsies and those obtained from prostatectomy specimens, as well as the determinants of biopsy understaging.

Methods

We considered for this study all 371 prostate cancer patients recorded at the Geneva Cancer Registry diagnosed from 2004 to 2006 who underwent a radical prostatectomy. We used the kappa statistic to evaluate the Gleason score concordance from biopsy and prostatectomy specimens. Logistic regression was used to determine the parameters that predict the undergrading of the Gleason score in prostate biopsies.

Results

The kappa statistic between biopsy and prostatectomy Gleason score was 0.42 (p < 0.0001), with 67% of patients exactly matched, and 26% (n = 95) patients with Gleason score underestimated by the biopsy. In a multi-adjusted model, increasing age, advanced clinical stage, having less than ten biopsy cores, and longer delay between the two procedures, were all independently associated with biopsy undergrading. In particular, the proportion of exact match increased to 72% when the patients had ten or more needle biopsy cores. The main limitation of the study is that both biopsy and prostatectomy specimens were examined by different laboratories.

Conclusions

The data show that concordance between biopsy and prostatectomy Gleason scores lies within the classic clinical standards in this population-based study. The number of biopsy cores appears to strongly impact on the concordance between biopsy and radical prostatectomy Gleason score.

Do apparent diffusion coefficient (ADC) values obtained using high b-values with a 3-T MRI correlate better than a transrectal ultrasound (TRUS)-guided biopsy with true Gleason scores obtained from radical prostatectomy specimens for patients with prostate cancer?

OBJECTIVE

To investigate the usefulness of apparent diffusion coefficient (ADC) values in predicting true Gleason scores from radical prostatectomy specimen (tGS), compared with systematic transrectal ultrasound (TRUS)-guided biopsy GS (bGS).

MATERIALS AND METHODS

One hundred and five patients with biopsy-proven prostate cancer underwent preoperative DWI (b-values of 0, 1000, and 2000s/mm(2)) of 3-T MRI. The mean and minimum ADCs of visible tumors were calculated for either of a pair of b-values: 0 and 1000s/mm(2) (ADC1000), or 0 and 2000s/mm(2) (ADC2000), and relationships between the four ADC parameters and tGS evaluated for the peripheral zone (PZ) and transition zone (TZ). For multiple tumors, the dominant tumor's GS and ADCs were estimated for cancer aggressiveness assessment by computing ROC curves.

RESULTS

Significant negative correlations were observed between tGS and mean ADC1000, mean ADC2000, minimum ADC1000, and minimum ADC2000 (r=-0.41, -0.39, -0.39, and -0.37, respectively) of 100 visible PZ tumors and 66 visible TZ tumors (r=-0.40, -0.42, -0.29, and -0.21, respectively). For distinguishing high-grade from low/intermediate-grade PZ lesions, the areas under the curve (AUCs) of mean ADC1000 (0.751), mean ADC2000 (0.710), minimum ADC1000 (0.768), and minimum ADC2000 (0.752) were similar to that of the highest bGS (0.708) (p=0.61, p=0.98, p=0.47, and p=0.60, respectively). For distinguishing high-grade from low/intermediate-grade TZ lesions, AUCs of mean ADC1000 (0.779), and mean ADC2000 (0.811) were similar to that of the highest bGS (0.805) (p=0.83 and p=0.97).

CONCLUSION

Tumor ADCs obtained with high b-values could predict prostate cancer aggressiveness as effectively as systematic TRUS-guided biopsy.

Gleason grading of prostate cancer in needle core biopsies: a comparison of general and urologic pathologists

BACKGROUND AND OBJECTIVES

The Gleason grading of prostate carcinoma (PCa) in needle core biopsies is a major determinant used in management planning. The objective of this study was to evaluate the concordance between general pathologists Gleason grading and that of a urologic pathologist in our community.

DESIGN AND SETTING

Retrospective review conducted at three tertiary care hospitals in Jeddah and Riyadh for all prostatic biopsies with carcinoma from January 2002 to January 2011.

METHODS

Gleason scores assigned by the original pathologist were compared with that of the reviewing urologic pathologists. Biopsies were originally obtained and diagnosed at different referring hospitals and independent laboratories. The kappa test was used to evaluate agreement between the original and review scores.

RESULTS

For 212 biopsies the exact concordance of the Gleason score assigned by the original pathologist and the reviewer was 38.7% (82/212). However, when grouped into the main four-score categories of 2-4, 5-6, 7, and 8 or greater, disagreement was noted in 88 (41.5%) biopsies; 87 were upgraded and 1 was downgraded on review. When grouped into two-score categories of low grade (≤6) and high grade (≥7), disagreement was noted in 32 (15%) of the biopsies.

CONCLUSION

Gleason grade score shows that there was only slight to fair agreement between outside and review scoring (kappa=0.43). When using only low versus high grade categorization, there was good agreement (kappa=0.69). Almost all of the cases with score disagreement were upgraded on review.