Karan Wadhwa

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

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.

Definitions of terms, processes and a minimum dataset for transperineal prostate biopsies: a standardization approach of the Ginsburg Study Group for Enhanced Prostate Diagnostics.

To define terms and processes and agree on a minimum dataset in relation to transperineal prostate biopsy procedures and enhanced prostate diagnostics. To identify the need for further evaluation and establish a collaborative research practice.

Magnetic Resonance and Ultrasound Image Fusion Supported Transperineal Prostate Biopsy Using the Ginsburg Protocol: Technique, Learning Points, and Biopsy Results

BACKGROUND Prostate biopsy supported by transperineal image fusion has recently been developed as a new method to the improve accuracy of prostate cancer detection. OBJECTIVE To describe the Ginsburg protocol for transperineal prostate biopsy supported by multiparametric magnetic resonance imaging (mpMRI) and transrectal ultrasound (TRUS) image fusion, provide learning points for its application, and report biopsy results. The article is supplemented by a Surgery in Motion video. DESIGN, SETTING, AND PARTICIPANTS This single-centre retrospective outcome study included 534 patients from March 2012 to October 2015. A total of 107 had no previous prostate biopsy, 295 had benign TRUS-guided biopsies, and 159 were on active surveillance for low-risk cancer. SURGICAL PROCEDURE A Likert scale reported mpMRI for suspicion of cancer from 1 (no suspicion) to 5 (cancer highly likely). Transperineal biopsies were obtained under general anaesthesia using BiopSee fusion software (Medcom, Darmstadt, Germany). All patients had systematic biopsies, two cores from each of 12 anatomic sectors. Likert 3-5 lesions were targeted with a further two cores per lesion. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Any cancer and Gleason score 7-10 cancer on biopsy were noted. Descriptive statistics and positive predictive values (PPVs) and negative predictive values (NPVs) were calculated. RESULTS AND LIMITATIONS The detection rate of Gleason score 7-10 cancer was similar across clinical groups. Likert scale 3-5 MRI lesions were reported in 378 (71%) of the patients. Cancer was detected in 249 (66%) and Gleason score 7-10 cancer was noted in 157 (42%) of these patients. PPV for detecting 7-10 cancer was 0.15 for Likert score 3, 0.43 for score 4, and 0.63 for score 5. NPV of Likert 1-2 findings was 0.87 for Gleason score 7-10 and 0.97 for Gleason score ≥4+3=7 cancer. Limitations include lack of data on complications. CONCLUSIONS Transperineal prostate biopsy supported by MRI/TRUS image fusion using the Ginsburg protocol yielded high detection rates of Gleason score 7-10 cancer. Because the NPV for excluding Gleason score 7-10 cancer was very high, prostate biopsies may not be needed for all men with elevated prostate-specific antigen values and nonsuspicious mpMRI. PATIENT SUMMARY We present our technique to sample (biopsy) the prostate by the transperineal route (the area between the scrotum and the anus) to detect prostate cancer using a fusion of magnetic resonance and ultrasound images to guide the sampling.

Salt-inducible kinase 2 regulates mitotic progression and transcription in prostate cancer.

Salt-inducible kinase 2 (SIK2) is a multifunctional kinase of the AMPK family that plays a role in CREB1-mediated gene transcription and was recently reported to have therapeutic potential in ovarian cancer. The expression of this kinase was investigated in prostate cancer clinical specimens. Interestingly, auto-antibodies against SIK2 were increased in the plasma of patients with aggressive disease. Examination of SIK2 in prostate cancer cells found that it functions both as a positive regulator of cell-cycle progression and a negative regulator of CREB1 activity. Knockdown of SIK2 inhibited cell growth, delayed cell-cycle progression, induced cell death, and enhanced CREB1 activity. Expression of a kinase-dead mutant of SIK2 also inhibited cell growth, induced cell death, and enhanced CREB1 activity. Treatment with a small-molecule SIK2 inhibitor (ARN-3236), currently in preclinical development, also led to enhanced CREB1 activity in a dose- and time-dependent manner. Because CREB1 is a transcription factor and proto-oncogene, it was posited that the effects of SIK2 on cell proliferation and viability might be mediated by changes in gene expression. To test this, gene expression array profiling was performed and while SIK2 knockdown or overexpression of the kinase-dead mutant affected established CREB1 target genes; the overlap with transcripts regulated by forskolin (FSK), the adenylate cyclase/CREB1 pathway activator, was incomplete. Implications: This study demonstrates that targeting SIK2 genetically or therapeutically will have pleiotropic effects on cell-cycle progression and transcription factor activation, which should be accounted for when characterizing SIK2 inhibitors. Mol Cancer Res; 13(4); 620–35. ©2014 AACR.

Synthetic lethality between androgen receptor signalling and the PARP pathway in prostate cancer

Emerging data demonstrate homologous recombination (HR) defects in castration-resistant prostate cancers, rendering these tumours sensitive to PARP inhibition. Here we demonstrate a direct requirement for the androgen receptor (AR) to maintain HR gene expression and HR activity in prostate cancer. We show that PARP-mediated repair pathways are upregulated in prostate cancer following androgen-deprivation therapy (ADT). Furthermore, upregulation of PARP activity is essential for the survival of prostate cancer cells and we demonstrate a synthetic lethality between ADT and PARP inhibition in vivo. Our data suggest that ADT can functionally impair HR prior to the development of castration resistance and that, this potentially could be exploited therapeutically using PARP inhibitors in combination with androgen-deprivation therapy upfront in advanced or high-risk prostate cancer.Tumours with homologous recombination (HR) defects become sensitive to PARPi. Here, the authors show that androgen receptor (AR) regulates HR and AR inhibition activates the PARP pathway in vivo, thus inhibition of both AR and PARP is required for effective treatment of high risk prostate cancer.

Investigating the ability of multiparametric MRI to exclude significant prostate cancer prior to transperineal biopsy

INTRODUCTION We characterized false negative prostate magnetic resonance imaging (MRI) reporting by using histology derived from MRI-transrectal ultrasound (TRUS)-guided transperineal (MTTP) fusion biopsies. METHODS In total, 148 consecutive patients were retrospectively reviewed. Men underwent multiparametric MRI (mpMRI), reported by a consultant/attending radiologist in line with European Society of Urogenital Radiology (ESUR) standards. MTTP biopsy of the lesions was performed according to the Ginsburg recommendations. Cases with an MRI-histology mismatch were identified and underwent a second read by an experienced radiologist. A third review was performed with direct histology comparison to determine a true miss from an MRI-occult cancer. Statistical analysis was performed with McNemars test. RESULTS False negative lesions were identified in 29 MRI examinations (19.6%), with a total of 46 lesions. Most false negative lesions (21/46) were located in the anterior sectors of the prostate. The second read led to a significant decrease of false-negative lesions with 7/29 further studies identified as positive on a patient-by-patient basis (24.1% of studies, p = 0.016) and 11/46 lesions (23.9%; p = 0.001). Of these, 30 lesions following the first read and 23 lesions after the second read were considered significant cancer according to the University College London criteria. However, on direct comparison with histology, most lesions were MRI occult. CONCLUSION We demonstrate that MRI can fail to detect clinically relevant lesions. Improved results were achieved with a second read but despite this, a number of lesions remain MRI-occult. Further advances in imaging are required to reduce false negative results.

Transperineal prostate biopsies for diagnosis of prostate cancer are well tolerated: a prospective study using patient-reported outcome measures.

We aimed to determine short-term patient-reported outcomes in men having general anesthetic transperineal (TP) prostate biopsies. A prospective cohort study was performed in men having a diagnostic TP biopsy. This was done using a validated and adapted questionnaire immediately post-biopsy and at follow-up of between 7 and 14 days across three tertiary referral hospitals with a response rate of 51.6%. Immediately after biopsy 43/201 (21.4%) of men felt light-headed, syncopal, or suffered syncope. Fifty-three percent of men felt discomfort after biopsy (with 95% scoring <5 in a 0-10 scale). Twelve out of 196 men (6.1%) felt pain immediately after the procedure. Despite a high incidence of symptoms (e.g., up to 75% had some hematuria, 47% suffered some pain), it was not a moderate or serious problem for most, apart from hemoejaculate which 31 men suffered. Eleven men needed catheterization (5.5%). There were no inpatient admissions due to complications (hematuria, sepsis). On repeat questioning at a later time point, only 25/199 (12.6%) of men said repeat biopsy would be a significant problem despite a significant and marked reduction in erectile function after the procedure. From this study, we conclude that TP biopsy is well tolerated with similar side effect profiles and attitudes of men to repeat biopsy to men having TRUS biopsies. These data allow informed counseling of men prior to TP biopsy and a benchmark for tolerability with local anesthetic TP biopsies being developed for clinical use.

Loss of hSef promotes metastasis through upregulation of EMT in prostate cancer

We have previously reported that the negative signaling regulator Similar Expression to FGF (hSef) is downregulated in prostate cancer and its loss is associated with clinical metastasis. Here, we explored the mechanistic basis of this finding. We first confirmed our clinical observation by testing hSef manipulation in an in vivo metastasis model. hSef stable expressing cells (PC3M‐hSef) or empty vector controls (PC3M‐EV) were injected subcutaneously into the lateral thoracic walls of NOD‐SCID gamma mice and lungs were harvested at autopsy. In this model, 6/7 PC3M‐EV xenografts had definitive lung micro‐metastasis whilst only 1/6 PC3M‐hSef xenografts exhibited metastasis recapitulating the clinical scenario (p = 0.03). Gene expression studies revealed key perturbations in genes involved in cell motility and epithelial to mesenchymal transition (EMT) along with alterations in cognate signaling pathways. These results were validated in an EMT specific PCR array whereby hSef over‐expression and silencing reciprocally altered E‐Cadherin expression (p = <0.001) amongst other EMT markers. Immunohistochemistry of excised tumors from the xenografts also confirmed the effect of hSef in suppressing E‐Cadherin expression at the protein level. Phosphokinase arrays further demonstrated a role for hSef in attenuating signaling of not only ERK‐MAPK but also the JNK and p38 pathways as well. Taken together, these data suggest evidence that loss of hSef may be a critical event facilitating tumor dissemination of prostate cancer through alteration of EMT. Detection of downregulated hSef, along with other negative regulators, may therefore be a useful biomarker heralding a transition to a metastatic phenotype and warrants further exploration in this context.

Identification of potential therapeutic targets in prostate cancer through a cross-species approach.

Genetically engineered mouse models of cancer can be used to filter genome‐wide expression datasets generated from human tumours and to identify gene expression alterations that are functionally important to cancer development and progression. In this study, we have generated RNAseq data from tumours arising in two established mouse models of prostate cancer, PB‐Cre/PtenloxP/loxP and p53loxP/loxPRbloxP/loxP, and integrated this with published human prostate cancer expression data to pinpoint cancer‐associated gene expression changes that are conserved between the two species. To identify potential therapeutic targets, we then filtered this information for genes that are either known or predicted to be druggable. Using this approach, we revealed a functional role for the kinase MELK as a driver and potential therapeutic target in prostate cancer. We found that MELK expression was required for cell survival, affected the expression of genes associated with prostate cancer progression and was associated with biochemical recurrence.

The role of prostatic urethral biopsies as a staging tool for bladder cancer

Objective: To determine the incidence of prostatic urethral involvement in our patient population and how prostatic urethral biopsy correlates with final cystectomy pathology. Patients and methods: We conducted a retrospective review of prostatic urethral biopsies (PUB) performed between February 2008 and April 2012 in a single centre. PUB pathology was correlated with cystectomy pathology. Results: PUB was undergone by 172 patients with a median age of 70 years (range: 37–84 years): There were 35 (20%) patients having a positive PUB and 137 (80%) who were negative. Of the 94 patients who underwent cystectomy, we found that when the entire prostatic urethra was sectioned, 20 (21%) patients had cancer in the prostatic urethra. Cancer was found in 17 (77%) of 22 patients with a positive PUB and in three (4%) out of the 72 with a negative PUB (positive predictive value (PPV) 77%, negative predictive value (NPV) 96%, sensitivity 85% and specificity 93%). In all 94 patients, the prostatic apical margin was negative. Conclusion: Disease in the prostatic urethra affected 20% of patients, consistent with published data. Prostatic urethral apical margins were all negative. Intra-operative frozen section would have missed cancer in the 20 patients with prostatic urethral cancer, whereas PUB identified 17 (85%) of the 20 patients. These data confirm the value of using PUB before cystectomy, in our UK population.