Maret Böhm

Multiparametric Magnetic Resonance Imaging Guided Diagnostic Biopsy Detects Significant Prostate Cancer and could Reduce Unnecessary Biopsies and Over Detection: A Prospective Study

PURPOSE Multiparametric magnetic resonance imaging appears to improve prostate cancer detection but prospective studies are lacking. We determined the accuracy of multiparametric magnetic resonance imaging for detecting significant prostate cancer before diagnostic biopsy in men with abnormal prostate specific antigen/digital rectal examination. MATERIALS AND METHODS In this single center, prospective study men older than 40 years with abnormal prostate specific antigen/digital rectal examination and no previous multiparametric magnetic resonance imaging underwent T2-weighted, diffusion-weighted and dynamic contrast enhanced imaging without an endorectal coil. Imaging was allocated alternately to 1.5/3.0 Tesla. Imaging was double reported independently using PI-RADS (Prostate Imaging Reporting and Data System) by specialist radiologists. Transperineal grid directed 30-core biopsy was performed with additional magnetic resonance imaging directed cores for regions of interest outside template locations. Four significant cancer definitions were tested. Chi-square and logistic regression analysis was done. Men undergoing prostatectomy were analyzed. RESULTS Of the 165 men who enrolled in the study 150 were analyzed. Median age was 62.4 years, median prostate specific antigen was 5.6 ng/ml, 29% of patients had an abnormal digital rectal examination and 88% underwent initial biopsy. Multiparametric magnetic resonance imaging was positive (PI-RADS 3 to 5) in 66% of patients, 61% had prostate cancer and 30% to 41% had significant prostate cancer (definitions 1 to 4). For significant cancer sensitivity was 93% to 96%, specificity was 47% to 53%, and negative and positive predictive values were 92% to 96% and 43% to 57%, respectively (definitions 1 to 4). Radical prostatectomy results in 48 men were similar. Aggregate PI-RADS (4 to 20) performed similarly to overall PI-RADS (1 to 5). Negative and positive predictive values (100% and 71%, respectively) were similar in men at higher risk, defined as prostate specific antigen greater than 10 ng/ml with abnormal digital rectal examination. On multivariate analysis PI-RADS score was associated with significant prostate cancer (p <0.001) but magnet strength was not. Adding PI-RADS to the multivariate model improved the AUC from 0.810 to 0.913 (95% CI 0.038-0.166, p = 0.002). Radiologist agreement was substantial (weighted κ = 0.626). CONCLUSIONS Multiparametric magnetic resonance imaging reported by expert radiologists achieved an excellent negative predictive value and a moderate positive predictive value for significant prostate cancer at 1.5 and 3.0 Tesla.

Superior Quality of Life and Improved Surgical Margins Are Achievable with Robotic Radical Prostatectomy After a Long Learning Curve: A Prospective Single-surgeon Study of 1552 Consecutive Cases

BACKGROUND Comparative studies suggest functional and perioperative superiority of robot-assisted radical prostatectomy (RARP) over open radical prostatectomy (ORP). OBJECTIVE To determine whether high-volume experienced open surgeons can improve their functional and oncologic outcomes with RARP and, if so, how many cases are required to surpass ORP outcomes and reach the learning curve plateau. DESIGN, SETTING, AND PARTICIPANTS A prospective observational study compared two surgical techniques: 1552 consecutive men underwent RARP (866) or ORP (686) at a single Australian hospital from 2006 to 2012, by one surgeon with 3000 prior ORPs. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Demographic and clinicopathologic data were collected prospectively. The Expanded Prostate Cancer Index Composite quality of life (QoL) questionnaire was administered at baseline, 1.5, 3, 6, 12, and 24 mo. Multivariate linear and logistic regression modelled the difference in QoL domains and positive surgical margin (PSM) odds ratio (OR), respectively, against case number. RESULTS AND LIMITATIONS A total of 1511 men were included in the PSM and 609 in the QoL analysis. RARP sexual function scores surpassed ORP scores after 99 RARPs and increased to a mean difference at 861st case of 11.0 points (95% confidence interval [CI], 5.9-16.1), plateauing around 600-700 RARPs. Early urinary incontinence scores for RARP surpassed ORP after 182 RARPs and increased to a mean difference of 8.4 points (95% CI, 2.1-14.7), plateauing around 700-800 RARPs. The odds of a pT2 PSM were initially higher for RARP but became lower after 108 RARPs and were 55% lower (OR: 0.45; 95% CI, 0.22-0.92) by the 866th RARP. The odds of a pT3/4 PSM were initially higher for RARP but decreased, plateauing around 200-300 RARPs with an OR of 1.15 (0.68-1.95) at the 866th RARP. Limitations include single-surgeon data and residual confounding. CONCLUSIONS RARP had a long learning curve with inferior outcomes initially, and then showed progressively superior sexual, early urinary, and pT2 PSM outcomes and similar pT3 PSM and late urinary outcomes. Learning RARP was worthwhile for this high-volume surgeon, but the learning curve may not be justifiable for late-career/low-volume surgeons; further studies are needed.

A role for GATA-2 in transition to an aggressive phenotype in prostate cancer through modulation of key androgen-regulated genes

GATA-2, a member of the GATA family of transcription factors, is involved in androgen receptor (AR) signaling, however, little is known regarding its role in prostate cancer. Here, we report that GATA-2 is expressed in a substantial proportion of prostate cancers and that high expression of GATA-2 is associated with biochemical recurrence and distant metastatic progression in a validation set of 203 cancers. In vitro data show that GATA-2 is directly recruited to the promoter region of the AR upon androgen stimulation of LNCaP prostate cancer cells with 5α-dihydroxytestosterone (DHT) for 24 h. Ectopic GATA-2 expression causes the induction of AR transcript levels under androgen-depleted conditions (P<0.05). The expression of the AR target gene, AZGP1, is induced upon androgen stimulation and this effect is repressed by GATA-2. In contrast, GATA-2 significantly increases transcript levels of KLK2, which increases further in a time-dependent manner on DHT treatment and in the presence of GATA-2. These results indicate that upregulation of GATA-2 may contribute to the progression to aggressive prostate cancer through modulation of expression of AR and key androgen-regulated genes, one of which, AZGP1, is associated with the progression to metastatic disease.

Focal irreversible electroporation for prostate cancer: functional outcomes and short-term oncological control.

Background:Current data on the use of irreversible electroporation (IRE) in the treatment of prostate cancer (PCa) is limited. We aim to evaluate the safety, short-term functional and oncological outcomes of focal IRE in low-intermediate risk PCa.Methods:Between February 2013 and May 2014, 32 consecutive men underwent IRE at a single centre. Patients with low-intermediate risk PCa who had not received previous PCa treatment were included for analysis. The tumour was ablated using 3–6 electrodes, ensuring a minimum 5-mm safety margin around the visible magnetic resonance imaging (MRI) lesion. Follow-up included recording Clavien complications, Expanded Prostate Cancer Index Composite (EPIC) questionnaires (baseline, 1.5, 3, 6 months), 6-month multi-parametric MRI (mp-MRI) and 7-month biopsy. Findings on mp-MRI and biopsy were sub-divided into infield, adjacent or outfield of the treatment zone.Results:Twenty-five men were included for final analysis. Safety follow-up revealed one Clavien Grade 3 complication and five Grade 1 complications. Functional follow-up confirmed no significant change in American Urological Association urinary symptom score, sexual or bowel function. Infield, there were no suspicious findings on mp-MRI (n=24) or biopsy (n=21) in all patients. Adjacent to the treatment zone, five (21%) had suspicious findings on mp-MRI with four (19%) proving to be significant on biopsy. Outfield, there were two (8%) with suspicious findings on mp-MRI and one (5%) significant finding on biopsy. For the five patients with significant findings on follow-up biopsy, one is awaiting repeat IRE, one had radical prostatectomy and three remained on active surveillance.Conclusions:In selected patients with low-intermediate risk PCa, focal IRE appears to be safe with minimal morbidity. There were no infield recurrences and 76% of patients were histologically free of significant cancer at 8 months. Almost all recurrences were adjacent to the treatment zone, and this was addressed by widening the treatment margins.

A multiparametric magnetic resonance imaging-based risk model to determine the risk of significant prostate cancer prior to biopsy

To develop and externally validate a predictive model for detection of significant prostate cancer.

Combination of multiparametric MRI and transperineal template‐guided mapping biopsy of the prostate to identify candidates for hemi‐ablative focal therapy

To evaluate the accuracy of combined multiparametric magnetic resonance imaging (mpMRI) and transperineal template‐guided mapping biopsy (TTMB) for identifying lobes with significant prostate cancer (PCa) for the application of hemi‐ablative focal therapy (FT).

Radiomic features for prostate cancer detection on MRI differ between the transition and peripheral zones: Preliminary findings from a multi-institutional study

To evaluate in a multi‐institutional study whether radiomic features useful for prostate cancer (PCa) detection from 3 Tesla (T) multi‐parametric MRI (mpMRI) in the transition zone (TZ) differ from those in the peripheral zone (PZ).

Gene Based Prediction of Clinically Localized Prostate Cancer Progression After Radical Prostatectomy

PURPOSE Accurate estimates of recurrence risk are needed for optimal treatment of patients with clinically localized prostate cancer. We combined an established nomogram and what to our knowledge are novel molecular predictors into a new prognostic model of prostate specific antigen recurrence. MATERIALS AND METHODS We analyzed gene expression profiles from formalin fixed, paraffin embedded, localized prostate cancer tissues to identify genes associated with prostate specific antigen recurrence. Profiles of the identified markers were reproduced by reverse transcriptase-polymerase chain reaction. We used the profiles of 3 of these genes along with output from the Kattan postoperative nomogram to produce a predictive model of prostate specific antigen recurrence. RESULTS After variable selection we built a model of prostate specific antigen recurrence combining expression values of 3 genes and the postoperative nomogram. The 3-gene plus nomogram model predicted 5-year prostate specific antigen recurrence with a concordance index of 0.77 in a validation set compared to a concordance index of 0.67 for the nomogram. This model identified a subgroup of patients at high risk for recurrence that was not identified by the nomogram. CONCLUSIONS This new gene based classifier has superior predictive power compared to that of the 5-year nomogram to assess the risk of prostate specific antigen recurrence in patients with organ confined prostate cancer. Our classifier should provide more accurate stratification of patients into high and low risk groups for treatment decisions and adjuvant clinical trials.

Focal irreversible electroporation as primary treatment for localized prostate cancer

To determine the safety, quality of life (QoL) and short‐term oncological outcomes of primary focal irreversible electroporation (IRE) for the treatment of localized prostate cancer (PCa), and to identify potential risk factors for oncological failure.

AutoStitcher: An Automated Program for Efficient and Robust Reconstruction of Digitized Whole Histological Sections from Tissue Fragments.

In applications involving large tissue specimens that have been sectioned into smaller tissue fragments, manual reconstruction of a “pseudo whole-mount” histological section (PWMHS) can facilitate (a) pathological disease annotation, and (b) image registration and correlation with radiological images. We have previously presented a program called HistoStitcher, which allows for more efficient manual reconstruction than general purpose image editing tools (such as Photoshop). However HistoStitcher is still manual and hence can be laborious and subjective, especially when doing large cohort studies. In this work we present AutoStitcher, a novel automated algorithm for reconstructing PWMHSs from digitized tissue fragments. AutoStitcher reconstructs (“stitches”) a PWMHS from a set of 4 fragments by optimizing a novel cost function that is domain-inspired to ensure (i) alignment of similar tissue regions, and (ii) contiguity of the prostate boundary. The algorithm achieves computational efficiency by performing reconstruction in a multi-resolution hierarchy. Automated PWMHS reconstruction results (via AutoStitcher) were quantitatively and qualitatively compared to manual reconstructions obtained via HistoStitcher for 113 prostate pathology sections. Distances between corresponding fiducials placed on each of the automated and manual reconstruction results were between 2.7%–3.2%, reflecting their excellent visual similarity.