Transperineal Template Prostate Mapping Research Articles

A Comprehensive Assessment of the Utility of Transperineal Template Prostate Mapping Biopsy: A 13-year Experience

To assess Duke's experience on the utility of TTMB for re-evaluating patients with persistently elevated PSA after prior negative biopsy, with pre-existing prostate cancer (PCa) already on active surveillance (AS), or considering focal therapy (FT). We retrospectively reviewed Duke patients undergoing TTMB. Functional outcomes were evaluated using International Index of Erectile Function-5 (IIEF-5) and International Prostate Symptom Score (IPSS). Complications within 30 days were recorded. Nonparametric statistical analyses compared functional measures from baseline to 2- and 6- weeks post-TTMB. From 8/2009-1/2021, 218 patients underwent TTMB, with 57-month median follow-up. Complication rate was 17.4%, with the majority Clavien I. Overall PCa detection was 72.9%, with csPCa in 53.2%; for those without prior PCa diagnosis (n=117), overall detection was 64.1% with csPCa in 49.5%. Of those on AS at TTMB (n=86), 36 (41.8%) had Gleason upgrading. TTMB changed management for 59 (68.6%) patients, with 38 (44.2%) proceeding to whole-gland therapy and 21 (24.4%) electing FT. Regarding functional outcomes, IPSS scores were insignificantly different from baseline at 6-weeks (p = NS). Overall functional score impacts were minimal across subgroups; in groups with significant declines in IIEF-5, median score drops were ≤1 point and caused minimal/no movement in IIEF-5 scoring category. In this cohort, TTMB offered enhanced cancer detection with overall minimal impact to functional outcomes. We conclude from this comprehensive assessment that TTMB provides value to rule out PCa, prevent overtreatment of those that can remain on AS, evaluate FT candidacy, and identify those needing whole-gland management.

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

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

Can quantitative analysis of multi-parametric MRI independently predict failure of focal salvage HIFU therapy in men with radio-recurrent prostate cancer?

ObjectivesFocal salvage HIFU is a feasible therapeutic option in some men who have recurrence after primary radiotherapy for prostate cancer. We aimed to determine if multi-parametric quantitative parameters, in addition to clinical factors, might have a role in independently predicting focal salvage HIFU outcomes. MethodsA retrospective registry analysis included 150 consecutive men who underwent focal salvage HIFU (Sonablate500) (2006-2015); 89 had mpMRI available. Metastatic disease was excluded by nodal assessment on pelvic MRI, a radioisotope bone-scan and/or choline or FDG PET/CT scan. All men had mpMRI and either transperineal template prostate mapping biopsy or targeted and systematic TRUS-biopsy. mpMRI included T2‐weighted, diffusion‐weighted and dynamic contrast‐enhancement. Pre-HIFU quantitative mpMRI data was obtained using Horos DICOM Viewer v3.3.5 for general MRI parameters and IB DCE v2.0 plug-in. Progression-free survival (PFS) was defined by biochemical failure and/or positive localized or distant imaging results and/or positive biopsy and/or systemic therapy and/or metastases/prostate cancer‐specific death. Potential predictors of PFS were analyzed by univariable and multivariable Cox-regression. ResultsMedian age at focal salvage HIFU was 71 years (interquartile range [IQR] 65–74.5) and median PSA pre-focal salvage treatment was 5.8ng/ml (3.8-8). Median follow-up was 35 months (23-47) and median time to failure was 15 months (7.8–24.3). D-Amico low, intermediate and high-risk disease was present in 1% (1/89), 40% (36/89) and 43% (38/89) prior to focal salvage HIFU (16% missing data). 56% (50/89) failed by the composite outcome. A total of 22 factors were evaluated on univariable and 8 factors on multivariable analysis. The following quantitative parameters were included: Ktrans, Kep, Ve, Vp, IS, rTTP and TTP. On univariable analysis, PSA, prostate volume at time of radiotherapy failure and Ve (median) value were predictors for failure. Ve represents extracellular fraction of the whole tissue volume. On multivariable analysis, only Ve (median) value remained as an independent predictor. ConclusionsOne pharmacokinetic quantitative parameter based on DCE sequences seems to independently predict failure following focal salvage HIFU for radio-recurrent prostate cancer. This likely relates to the tumor microenvironment producing heat-sinks which counter the heating effect of HIFU. Further validation in larger datasets and evaluating mechanisms to reduce heat-sinks are required.

MRI and targeted biopsies compared to transperineal mapping biopsies for targeted ablation in recurrent prostate cancer after radiotherapy: Primary outcomes of the FORECAST trial.

5009 Background: Radiotherapy is a common and effective treatment for localised prostate cancer. However, recurrence of cancer can occur in 10-15% of men in the following 5 years. Most patients with recurrence are managed using hormonal therapy with associated systemic side-effects and subsequent development of castrate resistance. Salvage prostatectomy confers a high risk of urine incontinence and rectal injury. Accurately localising and ablating only areas of recurrence within the prostate might be effective with fewer side-effects. The FOcal RECurrent Assessment and Salvage Treatment (FORECAST) trial assessed this diagnostic and treatment pathway for men with radiorecurrent cancer (NCT01883128). Methods: We first compared the accuracy of multi-parametric MRI (mp-MRI) and MRI-targeted biopsy in identifying areas of recurrent cancer to a transperineal template prostate mapping (TTPM) biopsy (Apr/2014-Jan/2018) in 181 patients from 6 UK centres. We then assessed the functional and cancer control outcomes of focally ablating areas of intraprostatic recurrence in 93 patients with localised or metastatic cancer (using cryotherapy or HIFU). Primary outcomes were sensitivity of mpMRI and MRI-targeted biopsies and urinary continence after focal ablation. A key secondary outcome was progression free survival (PFS) defined as no new metastases or hormone use (localised group only), or chemotherapy or further local treatment. Results: Of 181 men with suspicion of recurrence following radiotherapy, re-staging whole-body imaging (Choline PET and Bone Scan) showed localised disease in 128 (71%), nodal disease only in 13 (7%) and 38 (21%) metastatic. The sensitivity of MRI-targeted biopsy was 92% (95%CI 83-97%). Specificity, and positive and negative predictive values, were 75% (95%CI 45-92%), 94% (95%CI 86-98%) and 65% (95%CI 38-86%). 4/72 (6%) cancers were missed on TTPM biopsies alone and 6/72 (8%) were missed on MRI-targeted biopsies alone. Overall sensitivity of mpMRI was 81% (95%CI 73-88%) using Likert score 4-5 to denote a positive test. Specificity, and positive and negative predictive values, were 88% (95%CI 73-98%), 96% (95%CI 90-99%) and 57% (95%CI 42-70%). In the 93 men undergoing focal ablation, urinary continence was preserved in 78/93 (84%); 5/93 (5%) had a CTCAE grade 3+ adverse events. There were no rectal injuries. With a median follow-up of 27.8 [SD 1.3] months, PFS was 66% [54-75] at 24-months. Metastases-free survival in the 73 men with localised disease was 80% [95%CI 68–88] at 24-months. There were no cancer specific deaths. Conclusions: Prostate mpMRI and MRI-targeted biopsies can accurately detect and localise recurrent prostate cancer following radiotherapy. Focal ablation to areas of intra-prostatic recurrence preserves continence in the majority of men with good cancer control. Clinical trial information: NCT01883128.

Detection and staging of radio-recurrent prostate cancer using multiparametric MRI.

We determined the sensitivity and specificity of multiparametric magnetic resonance imaging (MP-MRI) in detection of locally recurrent prostate cancer and extra prostatic extension in the post-radical radiotherapy setting. Histopathological reference standard was whole-mount prostatectomy specimens. We also assessed for any added value of the dynamic contrast enhancement (DCE) sequence in detection and staging of local recurrence. This was a single centre retrospective study. Participants were selected from a database of males treated with salvage prostatectomy for locally recurrent prostate cancer following radiotherapy. All underwent pre-operative prostate-specific antigen assay, positron emission tomography CT, MP-MRI and transperineal template prostate mapping biopsy prior to salvage prostatectomy. MP-MRI performance was assessed using both Prostate Imaging-Reporting and Data System v. 2 and a modified scoring system for the post-treatment setting. 24 patients were enrolled. Using Prostate Imaging-Reporting and Data System v. 2, sensitivity, specificity, positive predictive value and negative predictive value was 64%, 94%, 98% and 36%. MP-MRI under staged recurrent cancer in 63%. A modified scoring system in which DCE was used as a co-dominant sequence resulted in improved diagnostic sensitivity (61%-76%) following subgroup analysis. Our results show MP-MRI has moderate sensitivity (64%) and high specificity (94%) in detecting radio-recurrent intraprostatic disease, though disease tends to be under quantified and under staged. Greater emphasis on dynamic contrast images in overall scoring can improve diagnostic sensitivity. MP-MRI tends to under quantify and under stage radio-recurrent prostate cancer. DCE has a potentially augmented role in detecting recurrent tumour compared with the de novo setting. This has relevance in the event of any future modified MP-MRI scoring system for the irradiated gland.

Added value of diffusion-weighted images and dynamic contrast enhancement in multiparametric magnetic resonance imaging for the detection of clinically significant prostate cancer in the PICTURE trial.

To determine the additional diagnostic value of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCE) in men requiring a repeat biopsy within the PICTURE study. PICTURE was a paired-cohort confirmatory study in which 249 men who required further risk stratification after a previous non-magnetic resonance imaging (MRI)-guided transrectal ultrasonography-guided biopsy underwent a 3-Tesla (3T) multiparametic (mp)MRI consisting of T2-weighted imaging (T2W), DWI and DCE, followed by transperineal template prostate mapping biopsy. Each mpMRI was reported using a LIKERT score in a sequential blinded manner to generate scores for T2W, T2W+DWI and T2W+DWI+DCE. Area under the receiver-operating characteristic curve (AUROC) analysis was performed to compare the diagnostic accuracy of each combination. The threshold for a positive mpMRI was set at a LIKERT score ≥3. Clinically significant prostate cancer was analysed across a range of definitions including UCL/Ahmed definition 1 (primary definition), UCL/Ahmed definition 2, any Gleason ≥3 + 4 and any Gleason ≥4 + 3. Of 249 men, sequential MRI reporting was available for 246. There was a higher rate of equivocal lesions (44.6%) using T2W alone compared to the addition of DWI (23.9%) and DCE (19.8%). Using the primary definition of clinically significant disease, there was no significant difference in the overall accuracy between T2W, with an AUROC of 0.74 (95% confidence interval [CI] 0.68-0.80), T2W+DWI at 0.76 (95% CI 0.71-0.82), and T2W+DWI+DCE, with an AUROC of 0.77 (95% CI 0.71-0.82; P = 0.55). The AUROC values remained comparable using other definitions of clinically significant disease including UCL/Ahmed definition 2 (P = 0.79), Gleason ≥3 + 4 (P = 0.53) and Gleason ≥4 + 3 (P = 0.53). Using 3T MRI, a high level of diagnostic accuracy can be achieved using T2W as a single parameter in men with a prior biopsy; however, such a strategy can lead to a higher rate of equivocal lesions.

467 - A longitudinal study of patients undergoing active surveillance for low grade prostate cancer diagnosed at Transperineal Template Prostate Mapping

467 - A longitudinal study of patients undergoing active surveillance for low grade prostate cancer diagnosed at Transperineal Template Prostate Mapping

Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE): a prospective cohort validating study assessing Prostate HistoScanning.

Men with negative prostate biopsies or those diagnosed with low-risk or low-volume intermediate-risk prostate cancers often require a second prostate biopsy prior to a treatment decision. Prostate HistoScanning (PHS) is an ultrasound imaging test that might inform prostate biopsy in such men. PICTURE was a prospective, paired-cohort validating trial to assess the diagnostic accuracy of imaging in men requiring a further biopsy (clinicaltrials.gov, NCT01492270) (11 January 2012-29 January 2014). We enrolled 330 men who had undergone a prior TRUS biopsy but where diagnostic uncertainty remained. All eligible men underwent PHS and transperineal template prostate mapping (TTPM) biopsy (reference standard). Men were blinded to the imaging results until after undergoing TTPM biopsies. We primarily assessed the ability of PHS to rule out clinically significant prostate (negative predictive value [NPV] and sensitivity) for a target histological condition of Gleason ≥4+3 and/or a cancer core length (MCCL) ≥6 mm. We also assessed the role of visually estimated PHS-targeted biopsies. Of the 330 men enrolled, 249 underwent both PHS and TTPM biopsy. Mean (SD) age was 62 (7) years, median (IQR) PSA 6.8 (4.98-9.50) ng/ml, median (IQR) number of previous biopsies 1 (1-2) and mean (SD) gland size 37 (15.5) ml. One hundred and forty six (59%) had no clinically significant cancer. PHS classified 174 (70%) as suspicious. Sensitivity was 70.3% (95% CI 59.8-79.5) and NPV 41.3% (95% CI 27.0-56.8). Specificity and positive predictive value (PPV) were 14.7% (95% CI 9.1-22.0) and 36.8% (95% CI 29.6-44.4), respectively. In all, 213/220 had PHS suspicious areas targeted with targeting sensitivity 13.6% (95% CI 7.3-22.6), specificity 97.6% (95% CI 93.1-99.5), NPV 61.6% (95% CI 54.5-68.4) and PPV 80.0% (95% CI 51.9-95.7). PHS is not a useful test in men seeking risk stratification following initial prostate biopsy.

Immunohistochemical biomarker validation in highly selective needle biopsy microarrays derived from mpMRI-characterized prostates.

Diagnosing prostate cancer routinely involves tissue biopsy and increasingly image guided biopsy using multiparametric MRI (mpMRI). Excess tissue after diagnosis can be used for research to improve the diagnostic pathway and the vertical assembly of prostate needle biopsy cores into tissue microarrays (TMAs) allows the parallel immunohistochemical (IHC) validation of cancer biomarkers in routine diagnostic specimens. However, tissue within a biopsy core is often heterogeneous and cancer is not uniformly present, resulting in needle biopsy TMAs that suffer from highly variable cancer detection rates that complicate parallel biomarker validation. The prostate cores with the highest tumor burden (in terms of Gleason score and/or maximum cancer core length) were obtained from 249 patients in the PICTURE trial who underwent transperineal template prostate mapping (TPM) biopsy at 5 mm intervals preceded by mpMRI. From each core, 2 mm segments containing tumor or benign tissue (as assessed on H&E pathology) were selected, excised and embedded vertically into a new TMA block. TMA sections were then IHC-stained for the routinely used prostate cancer biomarkers PSA, PSMA, AMACR, p63, and MSMB and assessed using the h-score method. H-scores in patient matched malignant and benign tissue were correlated with the Gleason grade of the original core and the MRI Likert score for the sampled prostate area. A total of 2240 TMA cores were stained and IHC h-scores were assigned to 1790. There was a statistically significant difference in h-scores between patient matched malignant and adjacent benign tissue that is independent of Likert score. There was no association between the h-scores and Gleason grade or Likert score within each of the benign or malignant groups. The construction of highly selective TMAs from prostate needle biopsy cores is possible. IHC data obtained through this method are highly reliable and can be correlated with imaging. IHC expression patterns for PSA, PSMA, AMACR, p63, and MSMB are distinct in malignant and adjacent benign tissue but did not correlate with mpMRI Likert score.

Accuracy of Transperineal Targeted Prostate Biopsies, Visual Estimation and Image Fusion in Men Needing Repeat Biopsy in the PICTURE Trial

We evaluated the detection of clinically significant prostate cancer using magnetic resonance imaging targeted biopsies and compared visual estimation to image fusion targeting in patients requiring repeat prostate biopsies. The prospective, ethics committee approved PICTURE trial (ClinicalTrials.gov NCT01492270) enrolled 249 consecutive patients from January 11, 2012 to January 29, 2014. Men underwent multiparametric magnetic resonance imaging and were blinded to the results. All underwent transperineal template prostate mapping biopsies. In 200 men with a lesion this was preceded by visual estimation and image fusion targeted biopsies. As the primary study end point clinically significant prostate cancer was defined as Gleason4+3 or greater and/or any grade of cancer with a length of 6 mm or greater. Other definitions of clinically significant prostate cancer were also evaluated. Mean ± SD patient age was 62.6 ± 7 years, median prostate specific antigen was 7.17 ng/ml (IQR 5.25-10.09), mean primary lesion size was 0.37 ± 1.52 cc with a mean of 4.3 ± 2.3 targeted cores per lesion on visual estimation and image fusion combined, and a mean of 48.7 ± 12.3 transperineal template prostate mapping biopsy cores. Transperineal template prostate mapping biopsies detected 97 clinically significant prostate cancers (48.5%) and 85 insignificant cancers (42.5%). Overall multiparametric magnetic resonance imaging targeted biopsies detected 81 clinically significant prostate cancers (40.5%) and 63 insignificant cancers (31.5%). In the 18 cases (9%) of clinically significant prostate cancer on magnetic resonance imaging targeted biopsies were benign or clinically insignificant on transperineal template prostate mapping biopsy. Clinically significant prostate cancer was detected in 34 cases (17%) on transperineal template prostate mapping biopsy but not on magnetic resonance imaging targeted biopsies and approximately half was present in nontargeted areas. Clinically significant prostate cancer was found on visual estimation and image fusion in 53 (31.3%) and 48 (28.4%) of the 169 patients (McNemar test p = 0.5322). Visual estimation missed 23 clinically significant prostate cancers (13.6%) detected by image fusion. Image fusion missed 18 clinically significant prostate cancers (10.8%) detected by visual estimation. Magnetic resonance imaging targeted biopsies are accurate for detecting clinically significant prostate cancer and reducing the over diagnosis of insignificant cancers. To maximize detection visual estimation as well as image fusion targeted biopsies are required.

Patient Reported Outcome Measures for Transperineal Template Prostate Mapping Biopsies in the PICTURE Study

Transperineal template prostate mapping biopsy is an increasingly used method of procuring tissue from men with suspected prostate cancer. We report patient related outcome measures and adverse events in men in the PICTURE trial (ClinicalTrials.gov NCT01492270) who underwent this diagnostic test. A total of 249 men underwent multiparametric magnetic resonance imaging followed by transperineal template prostate mapping biopsy as a validation study. Functional outcomes before and after transperineal template prostate mapping were prospectively collected and recorded with questionnaires, including the I-PSS (International Prostate Symptom Score), the I-PSS-QoL (Quality of Life), the IIEF-15 (International Index of Erectile Function-15) and the EPIC (Expanded Prostate Cancer Index Composite) urinary function. Mean age was 62 years, median prostate specific antigen was 6.8 ng/ml and median gland size was 37 ml. At transperineal template prostate mapping biopsy a median of 49 cores (IQR 40-55) were taken. Mean time to complete the post-procedure patient related outcome measure questionnaires was 46 days. Adverse events included post-procedure acute urinary retention in 24% of patients, rectal pain in 26% and perineal pain in 41%. Transperineal template prostate mapping biopsy resulted in a statistically significant increase in scores on the I-PSS from 10.9 to 11.8 (p = 0.024) and the I-PSS-QoL from 1.57 to 1.76 (p= 0.03). The IIEF-15 erectile function score decreased by 23.2% from 47.7 to 38.7 (p <0.001). Significant deterioration was noted in all 5 of IIEF-15 functional domains, including erectile and orgasmic function, sexual desire, and intercourse and overall satisfaction (p <0.001). EPIC urinary scores showed no overall change from baseline. Transperineal template prostate mapping biopsy causes a high urinary retention rate and a detrimental impact on genitourinary functional outcomes, including deterioration in urinary flow and sexual function. Our findings can be used to ensure adequate counseling about transperineal template prostate mapping biopsies. The results point to a need for strategies such as multiparametric magnetic resonance imaging and targeted biopsies to minimize the harms of transperineal template prostate mapping biopsy.

Performance characteristics of multiparametric-MRI at a non-academic hospital using transperineal template mapping biopsy as a reference standard

ObjectivesTo evaluate diagnostic accuracy of mpMRI in a non-academic hospital using transperineal template prostate mapping (TPM) biopsy as a reference standard. Secondary objectives included evaluating why mpMRI missed significant cancer. Materials and methods101 men received pre-biopsy mpMRI and TPM-biopsy over 16 months. Disease status was assigned at hemigland level. Primary histological definition of clinical significance was Gleason grade >/ = 4 + 3 or maximum cancer core length (MCCL) >/ = 6 mm. Positive mpMRI was defined as Prostate Imaging Reporting and Data System (PI-RADS) score >/ = 3. ResultsMedian age 69 (IQR 62–76). Median PSA 7 ng/ml (IQR 4.6–9.8). mpMRI had sensitivity 76.9%, specificity 60.7%, PPV 40.4% and NPV 88.3% at primary definitions. For detecting any Gleason >/ = 7 mpMRI had sensitivity 73.2%, specificity 60.3%, PPV 41.4% and NPV 85.4%. Mean MCCL was lower where significant cancer was missed compared to those correctly identified (5.8 mm versus 7.7 mm respectively, p = 0.035). ConclusionmpMRI performance characteristics were very encouraging when compared to contemporary clinical trials. In a non-academic hospital setting, negative mpMRI was just as good at ruling-out significant disease, though the ability of positive mpMRI to accurately detect significant disease was lower. An mpMRI-guided diagnostic pathway should be accompanied by appropriate mpMRI protocol optimisation, training, and quality control.

Characterizing indeterminate (Likert-score 3/5) peripheral zone prostate lesions with PSA density, PI-RADS scoring and qualitative descriptors on multiparametric MRI.

To determine whether indeterminate (Likert-score 3/5) peripheral zone (PZ) multiparametric MRI (mpMRI) studies are classifiable by prostate-specific antigen (PSA), PSA density (PSAD), Prostate Imaging Reporting And Data System version 2 (PI-RADS_v2) rescoring and morphological MRI features. Men with maximum Likert-score 3/5 within their PZ were retrospectively selected from 330 patients who prospectively underwent prostate mpMRI (3 T) without an endorectal coil, followed by 20-zone transperineal template prostate mapping biopsies ＋/- focal lesion-targeted biopsy. PSAD was calculated using pre-biopsy PSA and MRI-derived volume. Two readers A and B independently assessed included men with both Likert-assessment and PI-RADS_v2. Both readers then classified mpMRI morphological features in consensus. Men were divided into two groups: significant cancer (≥ Gleason 3 ＋ 4) or insignificant cancer (≤ Gleason 3 ＋ 3)/no cancer. Comparisons between groups were made separately for PSA & PSAD using Mann-Whitney test and morphological descriptors with Fisher's exact test. PI-RADS_v2 and Likert-assessment were descriptively compared and percentage inter-reader agreement calculated. 76 males were eligible for PSA & PSAD analyses, 71 for PI-RADS scoring, and 67 for morphological assessment (excluding significant image artefacts). Unlike PSA (p = 0.915), PSAD was statistically different (p = 0.004) between the significant [median: 0.19 ng ml-2 (interquartile range: 0.13-0.29)] and non-significant/no cancer [median: 0.13 ng ml-2 (interquartile range: 0.10-0.17)] groups. Presence of mpMRI morphological features was not significantly different between groups. Subjective Likert-assessment discriminated patients with significant cancer better than PI-RADS_v2. Inter-reader percentage agreement was 83% for subjective Likert-assessment and 56% for PI-RADS_v2. PSAD may categorize presence of significant cancer in patients with Likert-scored 3/5 PZ mpMRI findings. Advances in knowledge: PSAD may be used in indeterminate PZ mpMRI to guide decisions between biopsy vs monitoring.

The PICTURE study: diagnostic accuracy of multiparametric MRI in men requiring a repeat prostate biopsy

Background:Transrectal prostate biopsy has limited diagnostic accuracy. Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE) was a paired-cohort confirmatory study designed to assess diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) in men requiring a repeat biopsy.Methods:All underwent 3 T mpMRI and transperineal template prostate mapping biopsies (TTPM biopsies). Multiparametric MRI was reported using Likert scores and radiologists were blinded to initial biopsies. Men were blinded to mpMRI results. Clinically significant prostate cancer was defined as Gleason ⩾4+3 and/or cancer core length ⩾6 mm.Results:Two hundred and forty-nine had both tests with mean (s.d.) age was 62 (7) years, median (IQR) PSA 6.8 ng ml (4.98–9.50), median (IQR) number of previous biopsies 1 (1–2) and mean (s.d.) gland size 37 ml (15.5). On TTPM biopsies, 103 (41%) had clinically significant prostate cancer. Two hundred and fourteen (86%) had a positive prostate mpMRI using Likert score ⩾3; sensitivity was 97.1% (95% confidence interval (CI): 92–99), specificity 21.9% (15.5–29.5), negative predictive value (NPV) 91.4% (76.9–98.1) and positive predictive value (PPV) 46.7% (35.2–47.8). One hundred and twenty-nine (51.8%) had a positive mpMRI using Likert score ⩾4; sensitivity was 80.6% (71.6–87.7), specificity 68.5% (60.3–75.9), NPV 83.3% (75.4–89.5) and PPV 64.3% (55.4–72.6).Conclusions:In men advised to have a repeat prostate biopsy, prostate mpMRI could be used to safely avoid a repeat biopsy with high sensitivity for clinically significant cancers. However, such a strategy can miss some significant cancers and overdiagnose insignificant cancers depending on the mpMRI score threshold used to define which men should be biopsied.

A comparison of Bayesian and non-linear regression methods for robust estimation of pharmacokinetics in DCE-MRI and how it affects cancer diagnosis

The aim of this work is to compare Bayesian Inference for nonlinear models with commonly used traditional non-linear regression (NR) algorithms for estimating tracer kinetics in Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI). The algorithms are compared in terms of accuracy, and reproducibility under different initialization settings. Further it is investigated how a more robust estimation of tracer kinetics affects cancer diagnosis. The derived tracer kinetics from the Bayesian algorithm were validated against traditional NR algorithms (i.e. Levenberg-Marquardt, simplex) in terms of accuracy on a digital DCE phantom and in terms of goodness-of-fit (Kolmogorov-Smirnov test) on ROI-based concentration time courses from two different patient cohorts. The first cohort consisted of 76 men, 20 of whom had significant peripheral zone prostate cancer (any cancer-core-length (CCL) with Gleason>3+3 or any-grade with CCL>=4mm) following transperineal template prostate mapping biopsy. The second cohort consisted of 9 healthy volunteers and 24 patients with head and neck squamous cell carcinoma. The diagnostic ability of the derived tracer kinetics was assessed with receiver operating characteristic area under curve (ROC AUC) analysis. The Bayesian algorithm accurately recovered the ground-truth tracer kinetics for the digital DCE phantom consistently improving the Structural Similarity Index (SSIM) across the 50 different initializations compared to NR. For optimized initialization, Bayesian did not improve significantly the fitting accuracy on both patient cohorts, and it only significantly improved the ve ROC AUC on the HN population from ROC AUC=0.56 for the simplex to ROC AUC=0.76. For both cohorts, the values and the diagnostic ability of tracer kinetic parameters estimated with the Bayesian algorithm weren’t affected by their initialization. To conclude, the Bayesian algorithm led to a more accurate and reproducible quantification of tracer kinetic parameters in DCE-MRI, improving their ROC-AUC and decreasing their dependence on initialization settings.

Transperineal Magnetic Resonance Imaging-targeted Biopsy versus Transperineal Template Prostate Mapping Biopsy in the Detection of Localised Radio-recurrent Prostate Cancer

AimsMulti-parametric magnetic resonance imaging (mpMRI) may identify radio-recurrent intra-prostatic cancer accurately. We aimed to compare visually directed MRI-targeted biopsies (MRI-TB) to an accurate reference standard – transperineal prostate mapping (TPM) biopsies with 5 mm sampling – in the detection of clinically significant cancer in men with biochemical failure after radiotherapy. Materials and methodsA retrospective registry analysis between 2006 and 2014 identified 77 men who had undergone mpMRI followed by MRI-TB and TPM. Clinical significance was set at two definitions of disease. Definition 1 was Gleason ≥ 4+3 and/or maximum cancer core length ≥ 6 mm. Definition 2 was Gleason ≥ 3+4 and/or maximum cancer core length ≥ 4 mm. ResultsOf the 77 patients included, the mean age was 70 years (range 61–82; standard deviation 5.03). The median prostate-specific antigen (PSA) at the time of external beam radiotherapy (EBRT) was 14 ng/ml (interquartile range 7.83–32.50). The most frequent EBRT dose given was 74 Gy over 37 fractions. Eight patients had iodine-seed implant brachytherapy or high dose rate brachytherapy. Neoadjuvant/adjuvant hormonal therapy use was reported in 38. The time from EBRT to biochemical recurrence was a median of 60 months (interquartile range 36.75–85.00). The median PSA at the time of mpMRI was 4.68 ng/ml (interquartile range 2.68–7.60). The median time between mpMRI and biopsy was 2.76 months (interquartile range 1.58–4.34). In total, 2392 TPM and 381 MRI-TB cores were taken with 18% and 50% cancer detection, respectively. Detection rates of definition 1 clinically significant cancer were 52/77 (68%) versus 55/77 (71%) for MRI-TB and TPM, respectively. MRI-TB was more efficient requiring 1 core versus 2.8 cores to detect definition 2 cancer. ConclusionMRI-TB seems to have encouraging detection rates for clinically significant cancer with fewer cores compared with TPM, although TPM had higher detection rates for smaller lower grade lesions.

The Prevalence of Clinically Significant Prostate Cancer According to Commonly Used Histological Thresholds in Men Undergoing Template Prostate Mapping Biopsies

Transrectal prostate biopsies are inaccurate and, thus, the prevalence of clinically significant prostate cancer in men undergoing biopsy is unknown. We determined the ability of different histological thresholds to denote clinically significant cancer in men undergoing a more accurate biopsy, that of transperineal template prostate mapping. In this multicenter, cross-sectional cohort of men who underwent template prostate mapping biopsies between May 2006 and January 2012, 4 different thresholds of significance combining tumor grade and burden were used to measure the consequent variation with respect to the prevalence of clinically significant disease. Of 1,203 men 17% (199) had no previous biopsy, 38% (455) had a prior negative transrectal ultrasound biopsy, 24% (289) were on active surveillance and 21% (260) were seeking risk stratification. Mean patient age was 63.5 years (SD 7.6) and median prostate specific antigen was 7.4 ng/ml (IQR 5.3-10.5). Overall 35% of the patients (424) had no cancer detected. The prevalence of clinically significant cancer varied between 14% and 83% according to the histological threshold used, in particular between 30% and 51% among men who had no previous biopsy, between 14% and 27% among men who had a prior negative biopsy, between 36% and 74% among men on active surveillance, and between 47% and 83% among men seeking risk stratification. According to template prostate mapping biopsy between 1 in 2 and 1 in 3 men have prostate cancer that is histologically defined as clinically significant. This suggests that the commonly used thresholds may be set too low.

Transperineal template prostate-mapping biopsies: an evaluation of different protocols in the detection of clinically significant prostate cancer.

To determine whether modified transperineal template prostate-mapping (TTPM) biopsy protocols, altering the template or the biopsy density, have sensitivity and negative predictive value (NPV) equal to full 5-mm TTPM. Retrospective analysis of an institutional registry including treatment-naïve men undergoing 5-mm TTPM biopsy analysed in a 20-zone fashion. The value of three modified strategies was assessed by comparing the information provided by selected zones against full 5-mm TTPM. Strategy 1, did not consider the findings of anterior areas; strategies 2 and 3 simulated a reduced biopsy density by excluding intervening zones. A bootstrapping technique was used to calculate reliable estimates of sensitivity and NPV of these three strategies for the detection of clinically significant disease (maximum cancer core length ≥4 mm and/or Gleason score ≥3 + 4). In all, 391 men with a median (interquartile range, IQR) age of 62 (58-67) years were included. The median (IQR) PSA level and PSA density were 6.9 (4.8-10) ng/mL and 0.17 (IQR 0.12-0.25) ng/mL/mL, respectively. A median (IQR) of 6 (2-9) cores out of 48 (33-63) taken per man were positive for prostate cancer. No cancer was detected in 67 men (17%), whilst low-, intermediate- and high-risk disease was identified in 78 (20%), 80 (21%), and 166 (42%), respectively. Strategy 1, 2 and 3 had sensitivities of 78% [95% confidence interval (CI) 73-84%], 85% (95% CI 80-90%) and 84% (95% CI 79-89%), respectively. The NPVs of the three strategies were 73% (95% CI 67-80%), 80% (95% CI 74-86%) and 79% (95% CI 72-84%), respectively. Altering the template or decreasing sampling density has a substantial negative impact on the ability of TTPM biopsy to exclude clinically significant disease. This should be considered when modified TTPM biopsy strategies are used to select men for tissue-preserving approaches, and when modified TTPM are used to validate new diagnostic tests.

The FORECAST study — Focal recurrent assessment and salvage treatment for radiorecurrent prostate cancer

BackgroundOne-third of men may experience biochemical failure by 8years following radical radiotherapy for localised prostate cancer. Over 90% of men are started on androgen deprivation therapy (ADT) which is non-curative and confers systemic side-effects. Focal salvage therapy (FST) limits collateral tissue damage and may improve therapeutic ratios. In order to deliver FST, distant disease must be ruled-out and intra-prostatic disease must be accurately detected, localised and characterised. AimFORECAST – Focal Recurrent Assessment and Salvage Treatment – is a study designed to evaluate a novel imaging-based diagnostic and therapeutic complex intervention pathway for men who fail radiotherapy. MethodsMen with biochemical failure following radical prostate radiotherapy, prior to salvage therapy will be recruited. They will undergo whole-body multi-parametric MRI (WB-MRI), choline PET/CT, bone-scan and pelvic-mpMRI and then MRI transperineal-targeted biopsies (MRI-TB) and Transperineal Template Prostate Mapping Biopsy (TPM). Those suitable for FST will undergo either high intensity focused ultrasound (HIFU) or cryotherapy. ResultsPrimary outcome measures: a) the accuracy of WB-MRI to detect distant metastatic disease; b) accuracy of prostate mpMRI in local detection of radiorecurrent prostate cancer; c) detection accuracy of MRI-TB; and d) rate of urinary incontinence following FST. ConclusionFocal salvage therapy may confer lower rates of morbidity whilst retaining disease control. In order to deliver FST, intra- and extra-prostatic disease must be detected early and localised accurately. Novel diagnostic techniques including WB-MRI and MRI-TB may improve the detection of distant and local disease whilst reducing healthcare burdens compared with current imaging and biopsy strategies.

Dosimetry Modeling for Focal Low-Dose-Rate Prostate Brachytherapy

Focal brachytherapy targeted to an individual lesion(s) within the prostate may reduce side effects experienced with whole-gland brachytherapy. The outcomes of a consensus meeting on focal prostate brachytherapy were used to investigate optimal dosimetry of focal low-dose-rate (LDR) prostate brachytherapy targeted using multiparametric magnetic resonance imaging (mp-MRI) and transperineal template prostate mapping (TPM) biopsy, including the effects of random and systematic seed displacements and interseed attenuation (ISA). Nine patients were selected according to clinical characteristics and concordance of TPM and mp-MRI. Retrospectively, 3 treatment plans were analyzed for each case: whole-gland (WG), hemi-gland (hemi), and ultra-focal (UF) plans, with 145-Gy prescription dose and identical dose constraints for each plan. Plan robustness to seed displacement and ISA were assessed using Monte Carlo simulations. WG plans used a mean 28 needles and 81 seeds, hemi plans used 17 needles and 56 seeds, and UF plans used 12 needles and 25 seeds. Mean D90 (minimum dose received by 90% of the target) and V100 (percentage of the target that receives 100% dose) values were 181.3 Gy and 99.8% for the prostate in WG plans, 195.7 Gy and 97.8% for the hemi-prostate in hemi plans, and 218.3 Gy and 99.8% for the focal target in UF plans. Mean urethra D10 was 205.9 Gy, 191.4 Gy, and 92.4 Gy in WG, hemi, and UF plans, respectively. Mean rectum D2 cm(3) was 107.5 Gy, 77.0 Gy, and 42.7 Gy in WG, hemi, and UF plans, respectively. Focal plans were more sensitive to seed displacement errors: random shifts with a standard deviation of 4 mm reduced mean target D90 by 14.0%, 20.5%, and 32.0% for WG, hemi, and UF plans, respectively. ISA has a similar impact on dose-volume histogram parameters for all plan types. Treatment planning for focal LDR brachytherapy is feasible. Dose constraints are easily met with a notable reduction to organs at risk. Treating smaller targets makes seed positioning more critical.