Techniques For Prostate Cancer Research Articles

Current role of focal therapy in prostate cancer.

Thanks to the improved accuracy of multiparametric Magnetic Resonance Imaging (mpMRI) to detect and localize the dominant index lesion on prostate cancer (PCa), the concept of minimally invasive focal treatments (FT) has gained popularity. Nevertheless, although high-quality evidence that FT has favorable functional outcomes, definitive proof of its oncological effectiveness compared to standard treatments remains underreported. This study aims to explore the efficacy, safety, oncologic and functional outcomes of different type of FT for PCa. A non-systematic literature review was conducted by searching on PubMed "prostate cancer" AND "focal treatment" OR "HIFU" OR "irreversible electroporation" OR "cryoablation" OR "focal laser ablation." Overall, 22 articles published in English literature from 2018 to 2023 describing FT techniques for PCa were included. Related to the field ablated, focal therapies include hemiablation (half gland), focal ablation (zonal-base) or targeted therapy (lesion-based). FT modalities can be categorized in thermal and non-thermal energy: thermal energy techniques include high-intensity focused ultrasound (HIFU), cryotherapy, radiofrequency ablation (RFA), and focal laser ablation (FLA). Focal brachytherapy, irreversible electroporation (IRE), and vascular-targeted photodynamic therapy (VTP) are classified as non-thermal ablation. Each focal ablative treatments could be promising alternative to conventional radical therapies to treat PCa in term of mid-term oncologic and functional outcomes, however, limited data are available in comparison with standardized radical treatments. HIFU and Cryo are the most studied techniques and seem to be superior to radical treatments in term of functional outcomes despite associated with higher recurrence and retreatment rate. Current evidences of oncologic and functional outcomes of FT are based mainly on retrospective, non-comparative and single center studies. Thus, none of the focal therapies available should be considered safe alternative to standardized treatments in routine practice and should be offered only for well selected PCa patients with low or at least favorable-intermediate risk disease, unfit for radical options.

State of the art and future challenges of urethra-sparing stereotactic body radiotherapy for prostate cancer: a systematic review of literature

PurposeDoses delivered to the urethra have been associated with an increased risk to develop long-term urinary toxicity in patients undergoing stereotactic body radiotherapy (SBRT) for prostate cancer (PCa). Aim of the present systematic review is to report on the role of urethra-sparing SBRT (US-SBRT) techniques for prostate cancer, with a focus on outcome and urinary toxicity.MethodA systematic review of the literature was performed on the PubMed database on May 2023. Based on the urethra-sparing technique, 13 studies were selected for the analysis and classified in the two following categories: “urethra-steering” SBRT (restriction of hotspots to the urethra) and “urethra dose-reduction” SBRT (dose reduction to urethra below the prescribed dose).ResultsBy limiting the urethra Dmax to 90GyEQD2 (α/β = 3 Gy) with urethra-steering SBRT techniques, late genitourinary (GU) grade 2 toxicity remains mild, ranging between 12.1% and 14%. With dose-reduction strategies decreasing the urethral dose below 70 GyEQD2, the risk of late GU toxicity was further reduced (< 8% at 5 years), while maintaining biochemical relapse-free survival rates up to 93% at 5 years.ConclusionUS-SBRT techniques limiting maximum doses to urethra below a 90GyEQD2 (α/β = 3 Gy) threshold result in a low rate of acute and late grade ≥ 2 GU toxicity. A better understanding of clinical factors and anatomical substructures involved in the development of GU toxicity, as well as the development and use of adapted dose constraints, is expected to further reduce the long-term GU toxicity of prostate cancer patients treated with SBRT.

Identification of early stage and metastatic prostate cancer using electrochemical detection of beta-2-microglobulin in urine samples from patients

To improve prostate cancer (PCa) diagnosis, it is imperative to identify novel biomarkers and establish effective screening techniques. Here, we introduce electrochemical biosensing of β-2-Microglobulin (β2M) in urine as a potential diagnostic tool for PCa. The immunosensor is composed of a screen-printed graphene electrode coated with anti β2M antibodies. The sensor is capable of detecting the protein directly in urine without any sample pretreatment within 45 min including sample incubation and a lower limit of detection of 204 µg/L. The sensor demonstrated a significant difference in the β2M-creatinine ratio in urine between control and both local- and metastatic PCa (mPCa) (P = 0.0302 and P = 0.0078 respectively), and between local- and mPCa (P = 0.0302). This first example of electrochemical sensing of β2M for the diagnosis of PCa may set the stage for an affordable, on-site screening technique for PCa.

Focal MR-Guided High-Dose-Rate Brachytherapy for Localized Prostate Cancer: A Prospective Clinical Trial

<h3>Purpose/Objective(s)</h3> Focal therapy has gained traction in the management of localized prostate cancer (PCa) based on the promise of equivalent oncologic outcomes with minimal toxicity compared to whole gland therapy. However, 20-45% of patients have persistent/recurrent disease within the first 2-5 years after most commonly-used ablative methods (e.g., HIFU, cryotherapy). Based on brachytherapy's (BT) well-established and long track-record of efficacy for PCa, we sought to test the focal therapy hypothesis in a prospective clinical trial of MR-guided HDR for men with localized PCa. <h3>Materials/Methods</h3> This prospective trial was approved in 2016 (UHN IRB# 16-5490; NCT02918253) for patients with clinically low- and favorable intermediate-risk prostate cancer, and a conspicuous lesion on mpMRI consistent with the area of pathological involvement. The CTV was derived from the mpMRI-defined GTV plus a 7 mm isotropic expansion, with 2 mm sup/inf added for the PTV. Implant and planning were performed with an MR-only workflow, and delivery with HDR BT. Treatment consisted of two separate implants within 14 days, to a prescription dose of 33-36 Gy in 2 sessions (BED ≥ 200 Gy). Biochemical recurrence (BCR), defined as > 2ng/mL above nadir was calculated using the Kaplan Meier method. Local failure, distant metastasis (DM) and toxicity events are reported as absolute rates. <h3>Results</h3> Nineteen patients have been treated, with a median age of 73 years (range 48-84), and median follow-up of 24 months (8-63). Median PSA was 6.1 ng/mL and 17/19 patients had Grade Group 2 disease. On average, the GTV and PTV corresponded to 3.56% (1.58-12.07) and 23.16% (13.71-40.75) of the median prostatic volume (40.49 cc [25.57-97.6]). Median number of catheters was 7 (4-11). Median GTV D₉₉ and PTV D₉₅ per fraction were 23.82 Gy (18.50-31.89) and 18.71 Gy (16.01-20.64), respectively. Nine patients have undergone the 2-yr local control ascertainment; 7 with mpMRI plus biopsies, and 2 with mpMRI only. At 2-years, local control and BCR-free survival were 100%; a single BCR event has been recorded 34 months after treatment. No DM or death events have occurred. The rate of treatment-related acute and late toxicities that were graded ≥ 2 was 0%. <h3>Conclusion</h3> Focal MRI-guided HDR brachytherapy as monotherapy appears to have a high therapeutic ratio and is a promising technique for localized PCa. Further follow-up will determine the durability of outcomes with this approach and the need for collaborative randomized studies.

Targeting the MALAT1 gene with the CRISPR/Cas9 technique in prostate cancer.

BackgroundThe MALAT1 lncRNA acts as an oncogene in Prostate cancer (PC); thus, it can be severe as a cancer biomarker.MethodsUsing bioinformatics datasets including (HTSeq-Counts, GDC, and TCGA) 5501 gene expression profiling specimens were gathered. Then, expression profiles and sample survival of lncRNA were investigated using COX regression analyses, ROC curve analysis. The Database for Annotation, Visualization, and Integrated Discovery was used to conduct GO and KEGG studies on the lncRNA-related PCGs. After MALAT1 Knockout via CRISPR/Cas9 technique, the MALAT1 expression was assessed in DU-145 cells. The deletion of the target fragment was examined by polymerase chain reaction (PCR). Also, the expression of apoptosis genes was investigated by qRT-PCR. The viability and cell proliferation were measured using the MTT assay. Cell migration capability was determined using the cell scratch assay. The results of qRT-PCR were assessed by the ΔΔCt method, and finally, statistical analysis was performed in SPSS software.ResultsA maximum of 451 lncRNAs were discovered to reflect different expressions between PC and non-carcinoma tissue samples, with 307 being upregulated and 144 being down-regulated. Thirty-six lncRNAs related to OS were carefully selected, which were then subjected to stepwise multivariate Cox regression analysis, with 2 lncRNAs (MALAT1, HOXB-AS3). MALAT1 is highly expressed in PC cells. MALAT1 Knockout in DU-145 cells increases apoptosis and prevents proliferation and migration, and DU-145 transfected cells were unable to migrate based on the scratch recovery test. Overall, data suggest that MALAT1 overexpression in PC helps metastasis and tumorigenesis. Also, MALAT1 knockout can be considered a therapeutic and diagnostic target in PC.ConclusionTargeting MALAT1 by CRISPR/Cas9 technique inhibit the cell proliferation and migration, and in addition induce apoptosis. Thus, MALAT1 can act as a tumor biomarker and therapeutic target.Supplementary InformationThe online version contains supplementary material available at 10.1186/s41021-022-00252-3.

MO-0059 Cost and toxicity comparisons of two IMRT techniques for prostate cancer: a micro-costing study

MO-0059 Cost and toxicity comparisons of two IMRT techniques for prostate cancer: a micro-costing study

A narrative review of MRI acquisition for MR-guided-radiotherapy in prostate cancer.

Magnetic resonance guided radiotherapy (MRgRT), enabled by the clinical introduction of the integrated MRI and linear accelerator (MR-LINAC), is a novel technique for prostate cancer (PCa) treatment, promising to further improve clinical outcome and reduce toxicity. The role of prostate MRI has been greatly expanded from the traditional PCa diagnosis to also PCa screening, treatment and surveillance. Diagnostic prostate MRI has been relatively familiar in the community, particularly with the development of Prostate Imaging - Reporting and Data System (PI-RADS). But, on the other hand, the use of MRI in the emerging clinical practice of PCa MRgRT, which is substantially different from that in PCa diagnosis, has been so far sparsely presented in the medical literature. This review attempts to give a comprehensive overview of MRI acquisition techniques currently used in the clinical workflows of PCa MRgRT, from treatment planning to online treatment guidance, in order to promote MRI practice and research for PCa MRgRT. In particular, the major differences in the MRI acquisition of PCa MRgRT from that of diagnostic prostate MRI are demonstrated and explained. Limitations in the current MRI acquisition for PCa MRgRT are analyzed. The future developments of MRI in the PCa MRgRT are also discussed.

Curative 3D Conformal Radiotherapy of Non-Operated Prostate Adenocarcinoma at Pointe-a-Pitre University Hospital (Guadeloupe): About 29 Cases

Context: Technological advances have improved the toxicities of radiotherapy. We are evaluating the 3D technique in prostate cancer. Materials and Methods: Retrospective study from January 2015 to December 2015 with 29 files. Survival was calculated by Kaplan-Meier method. Results: We collected 29 patient records over the study period. The median age was 75 years with the following extremes: 54 years and 83 years. The median PSA level was 12 ng/ml with a range of 3.05 to 79 ng/ml. Gleason score analysis showed 6 patients (20.69%) with a score of 6 (3 + 3), 23 patients (79.31%) with a score of 7 including 12 patients (41.38%) with grade 3 and 11 patients (37.93%) with grade 4. The median dose delivered was 74 Gy, with a mean dose of 73.79 Gy and extremes of 70 Gy for the minimum and 76 Gy for the maximum. Hormone therapy was combined with radiotherapy in 17 patients (58.62%). Seven patients (24.14%) had grade 1 acute bladder toxicity and one patient (3.45%) had grade 2 acute toxicity. Late bladder toxicity was grade 1 in 5 patients (17.24%), grade 2 in 3 patients (10.34%) and grade 3 in 1 patient (3.45%). Late rectal toxicity, grade 2 in 3 patients (10.34%), grade 3 in 1 patient, was noted. Overall survival at 2 years was 100% and 89.65% at 5 years. Relapse-free survival at 2 years was 82.76% and 62.07% at 5 years. There were 3 deaths (10.34%) of which only one was related to prostate cancer. Conclusion: Radiotherapy, like surgery, is a fundamental option for the treatment of prostate cancers, particularly those that are locally advanced. It is gaining in importance with the improvement of techniques (IMRT, VMAT…) and new fractionations which contribute to the reduction of toxicities and the comfort of patients (shorter spread).

PSMA PET/CT in primary prostate cancer diagnostics: an overview of the literature

AbstractImaging with radiotracers targeting the prostate-specific membrane antigen (PSMA) receptor is identified as a promising novel technique in prostate cancer (PCa) detection. In this paper we aim to summarize the current knowledge derived from the literature as well as the authors’ experiences on PSMA PET/CT in initial staging of PCa. PSMA PET/CT lesion- and template-based sensitivity and specificity respectively ranged from 35.1–96.1% and 96–100%. Patient-based sensitivity and specificity respectively ranged from 33.3–100% and 95–100%. Accuracy was 92% (95% CI 88–95) versus 65% (95% CI 60–69) compared to conventional imaging (CT and skeletal scintigraphy). PSMA PET/CT is superior for detection of metastases in primary PCa compared to conventional imaging. Also, PSMA PET/CT has a high specificity and moderate sensitivity for lymph node detection in primary PCa. For adequate initial staging, extended pelvic lymph node dissection (ePLND) will still be required, however, PSMA PET/CT can induce important management changes.

Comparative Study of Fast Superposition, Superposition Algorithm in Intensity Modulated Radiotherapy Techniques for Prostate Cancer

This study aims to compare the dosimetric coverage of the Planning Target Volume (PTV) and the dose to main organs at risk (OARs) between two different algorithms fast superposition (FSUP), superposition (SUP) using intensity-modulated radiotherapy (IMRT) techniques for prostate cancer. Ten patients with prostate cancer were selected for this study. For each patient, IMRT plans were created with 6 MV photon beam quality using CMS XiO treatment planning system. The delivery of IMRT was carried out using the step and shoot techniques. The dose coverage for each patient was designated to an ICRU report 62 reference point in the PTV, medium coverage of the planned target volume to be 95% of the prescribed dose while the maximum dose in the target volume to be not greater than 107% of the prescribed dose. A hypofractionated prescription dose of 70 Gy/28# at 2.5 Gy per fraction was used. Besides we compared the number of MUs and OARs dose to D15%, D25%, D35%, D50% on both algorithm planning sets. For target, this evaluation was made with comparing the conformity index (CI) and homogeneity index (HI). In our study, the results show the OARs got less dose from the SUP algorithm compared to FSUP algorithms. Statistically not significant difference was observed in V107% of PTV, MU/CC, conformity Index (p = 0.057, p = 0.215, p = 0.370) and 95% PTV Volume received prescription dose from both Plans. But Homogeneity Index for both algorithms was statistically significant (p = 0.000, p = 0.001). For prostate cancer, the superposition algorithm showed better results in the IMRT plan compared to the fast superposition algorithm.

Comparison of surgical, oncological, and functional outcomes of robot-assisted and laparoscopic radical prostatectomy in patients with prostate cancer.

To compare the oncological and functional outcomes of robot-assisted radical prostatectomy (RARP) and laparoscopic radical prostatectomy (LRP). We compared patients who underwent the RARP (n=778) and LRP (n=48) techniques for prostate cancer between January 2008 and July 2017 in our clinic. Patient demographics, preoperative and postoperative data, pathologic evaluation, continence, and potency rates were collected and analyzed retrospectively. The preoperative and demographic data of the patients we included in our study were similar. The mean operation time estimated blood loss, length of hospitalization, and catheterization time were significantly shorter in the RARP group. The statistical analysis was in favor of robotic prostatectomy in the terms of the mean length of hospitalization, catheterization time, and early (<30 days) and intermediate (31-90 days) complications. Positive surgical margins and biochemical recurrence rates, and recovery of continence and erectile function, were similar in both groups. RARP and LRP in organ-confined prostate cancer are safe and effective methods. Robotic prostatectomy has a shorter operative time, length of hospitalization, catheterization time, and lower early and late complication rates.

Feasibility study of an electronic portal imaging based in vivo dose verification system for prostate stereotactic body radiotherapy

PurposeWe evaluated the feasibility of electronic portal imaging based 3D in-vivo dosimetry for stereotactic body radiation therapy (SBRT) technique in prostate cancer. Methods and materialsTo investigate error detectability limitations of iViewDose™ v.1.0.1 (Elekta, Stockholm, Sweden) for prostate SBRT cases, ten prostate cancer patients were selected and in-vivo electronic portal imaging devices dosimetry was performed. Also possible error scenarios including dose calibration, setup, collimator, multi leaf collimator and patient anatomy related inaccuracies were created to investigate detectability of EPID. For this purpose, a SBRT treatment was planned on BrainLab pelvis phantom (BrainLab Medical Systems, Westchester, IL) and irradiated after proving setup with cone beam computer tomography. After that incorrect plans were irradiated and obtained results were compared with original in vivo measurements. ResultsMean gamma analysis (γ% ≤ 1) passing rate of ten patients was found as 96.2%. Additionally, mean dose reference point difference between measurement and calculated in treatment planning system for clinical target volume, rectum, bladder, left and right femur heads were found as 1.4%, 8%, 20.8%, 2.3% and 4.5%, respectively. Phantom measurements showed that positional errors can be escape from detection. However, the incorrect treated plans including linac calibration, MLC positions and patient anatomy based errors could not have passed the in vivo dosimetry analysis. Conclusions: EPID-based 3D in vivo dosimetry software (iViewDose) provides an efficient safety check on the accuracy of dose delivery during prostate SBRT treatments. However, phantom results showed some limitation of the system.

Percutaneous MR-guided prostate cancer cryoablation technical updates and literature review.

Prostate cancer (PCa) is the most common malignant tumor in males. The benefits in terms of overall reduction in specific mortality due to the widespread use of Prostate Specific Antigen (PSA) screening and the advancements in the curative treatments (radical prostatectomy or radiotherapy) appear to have reached a plateau. There remains, however, the questions of overdiagnosis and overtreatment of such patients. Currently, the main challenge in the treatment of patients with clinically organ-confined PCa is to offer an oncologically efficient treatment with as little morbidity as possible.Amongst the arising novel curative techniques for PCa, cryoablation (CA) is the most established one, which is also included in the NICE and AUA guidelines. CA is commonly performed under ultrasound guidance with the inherent limitations associated with this technique. The recent advancements in MRI have significantly improved the accuracy of detecting and characterizing a clinically significant PCa. This, alongside the development of wide bore interventional MR scanners, has opened the pathway for in bore PCa treatment. Under MRI guidance, PCa CA can be used either as a standard whole gland treatment or as a tumor targeted one. With MR-fluoroscopy, needle guidance capability, multiplanar and real-time visualization of the iceball, MRI eliminates the inherent limitations of ultrasound guidance and can potentially lead to a lower rate of local complications.The aim of this review article is to provide an overview about PCa CA with a more specific insight on MR guided PCa CA; the limitations, challenges and applications of this novel technique will be discussed.

Comparison of biparametric MRI to full multiparametric MRI for detection of clinically significant prostate cancer.

Multiparametric magnetic resonance imaging (MP-MRI) and MRI/ultrasound (US) fusion-guided biopsy are becoming more widely used techniques for prostate cancer (PCa) diagnosis and management. However, their widespread adoption and use, where available, are limited by cost and added time. These limitations could be minimized if a biparametric MRI (BP-MRI) focusing on T2-weighted and diffusion-weighted imaging is performed. Herein we report the cancer detection rate of BP-MRI compared with full MP-MRI. Biopsy-naive and prior negative biopsy patients with clinical suspicion for PCa underwent MP-MRI with an imaging protocol incorporating narrow field-of-view T2-weighted, diffusion-weighted, and DCE pelvic MRI. Then patients underwent MRI/US fusion-guided biopsy of target lesions between November 2013 and October 2017. The pathology results were compared to the positivity of the DCE sequence compared to the BP-MRI findings alone. There were 648 targeted lesions biopsied in 344 patients. We defined biparametric screen filter positivity as both T2-weighted and diffusion-weighted imaging positivity for the same lesion. The majority of target lesions (552/648, 85%) were screen filter positive. For those that were screen filter negative, a minority (14/96, 15%) had DCE-positive findings. Of these, 2/3 (67%) cancer-positive cases were seen on T2-weighted imaging. For those 82 that were screen filter negative and DCE negative, the DCE phase would not have added imaging suspicion. Only 3/82 (3.7%) were cancer positive; 2 with low risk, grade group 1 cancer and 1 with intraductal carcinoma, all identified on targeted T2-weighted MRI positivity. BP-MRI for the evaluation of PCa and for guiding MRI/US fusion-targeted biopsy has the advantages of reducing cost, time, and contrast exposure of MP-MRI by eliminating the DCE phase. These benefits are realized without forfeiting valuable diagnostic information, as shown by similar cancer detection rates of BP-MRI and MP-MRI in this study, particularly for clinically significant cases of PCa.

Patient-Reported Outcomes (PROs) Comparing Pencil Beam Scanning (PBS) and Double Scatter/Uniform Scanning Proton Beam Therapy for Localized Prostate Cancer (PC): Analysis of PCG 001-09

The use of proton beam therapy (PBT) for treatment of prostate cancer (PC) is controversial. ASTRO recommends against use of PBT for PC outside of a clinical trial or prospective registry. A pivotal randomized controlled trial comparing PBT and photon-based treatment is underway. However, PBT delivery has evolved from “conventional” PBT techniques (uniform scanning/double scatter [US/DS]) to PBS technology since this trial was first activated. Although PBS is thought to be the most conformal method for PBT delivery, it is unknown whether differences in toxicity outcomes characterize the 2 techniques. PROs are widely recognized as the gold standard for subjective symptom reporting. This analysis compares PRO changes associated with PBS and US/DS techniques for localized PC in a prospective multicenter registry study. We evaluated PROs (bowel, urinary, and sexual QOL) with the expanded prostate cancer index composite (EPIC) instrument for men with low-to-intermediate-risk PC enrolled in PCG 001-09 (NCT01255748). The analysis was limited to men treated with PBT to the prostate ± seminal vesicles with conventionally fractionated radiation using US/DS or PBS techniques. PROs were assessed at baseline and 3, 6, and 12 mo, with changes at these time periods evaluated. Mean changes from baseline in the EPIC domains were tested using repeated measures models. The proportions of men with minimally important differences (MIDs) in each domain were assessed using repeated measures logistic models. A total of 1,164 men completed EPIC at baseline; 280 (24%) received PBS and 884 (76%) received US/DS. Completion rates were 67.9% at 3 mo, 67.6% at 6 mo, and 63.9% at 12 mo. Average QOL declines from baseline to 12 mo were significantly higher in PBS than in US/DS for urinary QOL (P<0.05), whereas declines in average bowel QOL (P=0.96) and sexual QOL (P=0.09) were not significantly different. Among men responding to EPIC at all 4 time points (n=480), the percentages reporting a 1 MID decline at 12 mo for PBS and US/DS were 33.73% and 27.96%, respectively, for urinary QOL (P=0.21); 47.31% and 41.82%, respectively, for bowel QOL (P=0.35); and 36.71% and 31.07%, respectively, for sexual QOL (P=0.97). Corresponding 2-MID declines were observed in 26.51% and 13.71% for urinary QOL (P<0.01), 33.33% and 29.87% for bowel QOL (P=0.48); and 16.46% and 16.67% for sexual QOL (P=0.81). This is the first comparative evaluation of PROs following 2 different PBT delivery techniques for men with PC. The results of this analysis, demonstrating increased urinary bother scores following PBS, warrant further investigation and highlight the urgent need for prospective evaluation of PBT for PC.

Contrast-Enhanced Transrectal Ultrasound in Focal Therapy for Prostate Cancer.

Contrast-enhanced transrectal ultrasound (CeTRUS) is an emerging imaging technique in prostate cancer (PCa) diagnosis and treatment. We review the utility and implications of CeTRUS in PCa focal therapy (FT). CeTRUS utilizes intravenous injection of ultrasound-enhancing agents followed by high-resolution ultrasound to evaluate tissue microvasculature and differentiate between benign tissue and PCa, with the latter demonstrating increased enhancement. The potential utility of CeTRUS in FT for PCa extends to pre-, intra- and post-operative settings. CeTRUS may detect PCa, facilitate targeted biopsy and aid surgical planning prior to FT. During FT, the treated area can be visualized as a well-demarcated non-enhancing zone and continuous real-time assessment allows immediate re-treatment if necessary. Following FT, the changes on CeTRUS are immediate and consistent, thus facilitating repeat imaging for comparison during follow-up. Areas suspicious for recurrence may be detected and target-biopsied. Enhancement can be quantified using time-intensity curves allowing objective assessment and comparison. Based on encouraging early outcomes, CeTRUS may become an alternative imaging modality in prostate cancer FT. Further study with larger cohorts and longer follow-up are needed.

Prostate Cancer Risk Assessment in Biopsy-naïve Patients: The Rotterdam Prostate Cancer Risk Calculator in Multiparametric Magnetic Resonance Imaging-Transrectal Ultrasound (TRUS) Fusion Biopsy and Systematic TRUS Biopsy

BackgroundThe value of multiparametric magnetic resonance imaging (mpMRI) and targeted biopsy (TBx) remains controversial for biopsy-naïve men when compared to transrectal ultrasound (TRUS)-guided systematic biopsy (SBx). Risk-based patient selection could help to selectively identify men with significant prostate cancer (PCa) and thus reduce unnecessary mpMRI and biopsies. ObjectivesTo compare PCa detection rates for mpMRI TBx with SBx and to determine the rate of potentially avoided mpMRI and biopsies through risk-based selection using the Rotterdam Prostate Cancer Risk Calculator (RPCRC). Design, setting, and participantsTwo-hundred consecutive biopsy-naïve men in two centres underwent mpMRI scanning, 12-core SBx, and subsequent MRI-TRUS TBx in the case of suspicious lesion(s) (Prostate Imaging-Reporting and Data System v.2 score ≥3). Outcome measurements and statistical analysisWe measured the detection rate for high-grade (Gleason score ≥ 3+4) PCa for TBx and SBx. We carried out a retrospective stratification according to RPCRC biopsy advice to determine the rate of mpMRI and biopsies that could potentially be avoided by RPCRC-based patient selection in relation to the rate of high-grade PCa missed. Results and limitationsTBx yielded high-grade PCa in 51 men (26%) and low-grade PCa in 14 men (7%), while SBx yielded high-grade PCa in 63 men (32%) and low-grade PCa in 41 men (21%). Four out of 73 men (5%) with negative RPCRC advice and 63 out of 127 men (50%) with positive advice had high-grade PCa. Upfront RPCRC-based patient selection for mpMRI and TBx would have avoided 73 out of 200 (37%) mpMRI scans, missing two out of 51 (4%) high-grade PCas. Limitations include the RPCRC definition of high- and low-grade PCa and different mpMRI techniques. ConclusionsmpMRI with TBx detected PCa with high Gleason score and avoided biopsy in low-grade PCa, but failed to detect all high-grade PCa when compared to SBx among biopsy-naïve men. Risk-based patient selection using the RPCRC can avoid one-third of mpMRI scans and SBx in biopsy-naïve men. Patient summaryMen with a suspicion of prostate cancer are increasingly undergoing a magnetic resonance imaging (MRI) scan. Although promising, MRI-targeted biopsy is not accurate enough to safely replace systematic prostate biopsy for now. Individualised assessment of prostate cancer risk using the Rotterdam Prostate Cancer Risk Calculator could avoid one-third of MRI scans and systematic prostate biopsies.

MP38-12 PROPENSITY SCORE ANALYSIS OF PATHOLOGICAL OUTCOME AT RADICAL PROSTATECTOMY FOR MAGNETIC RESONANCE IMAGING-TRANSRECTAL ULTRASOUND FUSION PROSTATE BIOPSY VERSUS UNTARGETED EXTENDED TRANSRECTAL ULTRASOUND GUIDED PROSTATE BIOPSY

You have accessJournal of UrologyProstate Cancer: Detection & Screening IV1 Apr 2017MP38-12 PROPENSITY SCORE ANALYSIS OF PATHOLOGICAL OUTCOME AT RADICAL PROSTATECTOMY FOR MAGNETIC RESONANCE IMAGING-TRANSRECTAL ULTRASOUND FUSION PROSTATE BIOPSY VERSUS UNTARGETED EXTENDED TRANSRECTAL ULTRASOUND GUIDED PROSTATE BIOPSY Hans Arora, Ahmed Elshafei, Yaw Nyame, Daniel Sun, Helen Liang, Nitin Yerram, Daniel Greene, Dominic Grimberg, Karishma Gupta, Shree Agrawal, Sudhir Isharwal, Paurush Babbar, Andrew Sun, Khaled Fareed, Michael Gong, Ryan Berglund, Eric Klein, Andrew Stephenson, Andrei Purysko, and J. Stephen Jones Hans AroraHans Arora More articles by this author , Ahmed ElshafeiAhmed Elshafei More articles by this author , Yaw NyameYaw Nyame More articles by this author , Daniel SunDaniel Sun More articles by this author , Helen LiangHelen Liang More articles by this author , Nitin YerramNitin Yerram More articles by this author , Daniel GreeneDaniel Greene More articles by this author , Dominic GrimbergDominic Grimberg More articles by this author , Karishma GuptaKarishma Gupta More articles by this author , Shree AgrawalShree Agrawal More articles by this author , Sudhir IsharwalSudhir Isharwal More articles by this author , Paurush BabbarPaurush Babbar More articles by this author , Andrew SunAndrew Sun More articles by this author , Khaled FareedKhaled Fareed More articles by this author , Michael GongMichael Gong More articles by this author , Ryan BerglundRyan Berglund More articles by this author , Eric KleinEric Klein More articles by this author , Andrew StephensonAndrew Stephenson More articles by this author , Andrei PuryskoAndrei Purysko More articles by this author , and J. Stephen JonesJ. Stephen Jones More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1165AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion-guided prostate biopsy has been shown to increase the detection of clinically significant prostate cancer (PCa) by targeting specific lesions at biopsy. Our objective was to evaluate the accuracy of MRI-TRUS fusion biopsy to determine final pathology at radical prostatectomy (RP) as compared to untargeted extended template TRUS-guided prostate biopsy. METHODS From a single institution database, 2,201 patients were identified who underwent both prostate biopsy and RP between 2006 and 2016. Propensity score matching was performed with the nearest neighbor method using R-programming version 3.3.1 and a 4:1 match ratio. A total of 101 men were identified who underwent MRI-TRUS plus standard template biopsies were subsequently matched to 404 men who underwent untargeted extended template TRUS biopsy. Matched covariates included age at diagnosis, initial prostate specific antigen (PSA), race, clinical stage, total number of cores retrieved at time of biopsy, and history of prior TRUS biopsy. Continuous variables were compared using Wilcoxon rank-sum tests and categorical variables were assessed with χ2 test. The concordance of Gleason score from biopsy to RP was assessed. RESULTS After propensity score matching, median age was 64 years (IQR 59.5-68.5), median PSA was 5.4 ng/mL (IQR 4.0-8.1), median prostate size was 48 grams (IQR 38.5-60), and median number of cores retrieved at time of biopsy was 15 (IQR 12-20). Of patients who received MRI-TRUS plus standard template biopsy, 67 of 99 (67.7%) showed concordant Gleason grading between biopsy and RP pathology, whereas 204 of 397 (51.4%) of extended template TRUS biopsy patients were concordant (p<0.01). Fewer MRI-TRUS plus standard template biopsy patients were either upgraded (26.3% versus 32.2%) or downgraded (6.1% versus 15.4%) from biopsy to RP (p<0.01). CONCLUSIONS Of men undergoing TRUS biopsy for the diagnosis of PCa, MRI-TRUS fusion plus standard template techniques have a higher concordance with final pathology at RP. Additionally, MRI-TRUS techniques demonstrated better accuracy with lower rates of upgrading and downgrading prostatectomy when compared to untargeted extended template TRUS biopsy independent of total number of cores taken. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e488-e489 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Hans Arora More articles by this author Ahmed Elshafei More articles by this author Yaw Nyame More articles by this author Daniel Sun More articles by this author Helen Liang More articles by this author Nitin Yerram More articles by this author Daniel Greene More articles by this author Dominic Grimberg More articles by this author Karishma Gupta More articles by this author Shree Agrawal More articles by this author Sudhir Isharwal More articles by this author Paurush Babbar More articles by this author Andrew Sun More articles by this author Khaled Fareed More articles by this author Michael Gong More articles by this author Ryan Berglund More articles by this author Eric Klein More articles by this author Andrew Stephenson More articles by this author Andrei Purysko More articles by this author J. 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Imaging metabolism with hyperpolarized (13)C-labeled cell substrates.

Non-invasive (13)C magnetic resonance spectroscopy measurements of the uptake and subsequent metabolism of (13)C-labeled substrates is a powerful method for studying metabolic fluxes in vivo. However, the technique has been hampered by a lack of sensitivity, which has limited both the spatial and temporal resolution. The introduction of dissolution dynamic nuclear polarization in 2003, which by radically enhancing the nuclear spin polarization of (13)C nuclei in solution can increase their sensitivity to detection by more than 10(4)-fold, revolutionized the study of metabolism using magnetic resonance, with temporal and spatial resolutions in the seconds and millimeter ranges, respectively. The principal limitation of the technique is the short half-life of the polarization, which at ∼20-30 s in vivo limits studies to relatively fast metabolic reactions. Nevertheless, pre-clinical studies with a variety of different substrates have demonstrated the potential of the method to provide new insights into tissue metabolism and have paved the way for the first clinical trial of the technique in prostate cancer. The technique now stands on the threshold of more general clinical translation. I consider here what the clinical applications might be, which are the substrates that most likely will be used, how will we analyze the resulting kinetic data, and how we might further increase the levels of polarization and extend polarization lifetime.

Reducing the Cost of Proton Radiation Therapy: The Feasibility of a Streamlined Treatment Technique for Prostate Cancer

Proton radiation therapy is an effective modality for cancer treatments, but the cost of proton therapy is much higher compared to conventional radiotherapy and this presents a formidable barrier to most clinical practices that wish to offer proton therapy. Little attention in literature has been paid to the costs associated with collimators, range compensators and hypofractionation. The objective of this study was to evaluate the feasibility of cost-saving modifications to the present standard of care for proton treatments for prostate cancer. In particular, we quantified the dosimetric impact of a treatment technique in which custom fabricated collimators were replaced with a multileaf collimator (MLC) and the custom range compensators (RC) were eliminated. The dosimetric impacts of these modifications were assessed for 10 patients with a commercial treatment planning system (TPS) and confirmed with corresponding Monte Carlo simulations. We assessed the impact on lifetime risks of radiogenic second cancers using detailed dose reconstructions and predictive dose-risk models based on epidemiologic data. We also performed illustrative calculations, using an isoeffect model, to examine the potential for hypofractionation. Specifically, we bracketed plausible intervals of proton fraction size and total treatment dose that were equivalent to a conventional photon treatment of 79.2 Gy in 44 fractions. Our results revealed that eliminating the RC and using an MLC had negligible effect on predicted dose distributions and second cancer risks. Even modest hypofractionation strategies can yield substantial cost savings. Together, our results suggest that it is feasible to modify the standard of care to increase treatment efficiency, reduce treatment costs to patients and insurers, while preserving high treatment quality.