Prostate cancer detection with magnetic resonance-ultrasound fusion biopsy: The role of systematic and targeted biopsies

Development of an orthotopic canine prostate cancer model expressing human GRPr

BACKGROUND

Ace-1 canine prostate cancer cells grow orthotopically in cyclosporine immunosuppressed laboratory beagles. We previously transfected (human Gastrin-Releasing Peptide Receptor, huGRPr) into Ace-1 cells and demonstrated receptor-targeted NIRF imaging with IR800-G-Abz4-t-BBN, an agonist to huGRPr. Herein, we used the new cell line to develop the first canine prostate cancer model expressing a human growth factor receptor.

METHODS

Dogs were immunosuppressed with cyclosporine, azathioprine, prednisolone, and methylprednisolone. Their prostate glands were implanted with Ace-1huGRPr cells. The implantation wounds were sealed with a cyanoacrylic adhesive to prevent extraprostatic tumor growth. Intraprostatic tumors grew in 4-5 week. A lobar prostatic artery was then catheterized via the carotid artery and 25-100 nmol IR800-Abz4-t-BBN was infused in 2 mL followed by euthanasia in dogs 1-2, and recovery for 24 h before euthanasia in dogs 3-6. Excised tissues were imaged optically imaged, and histopathology performed.

RESULTS

Dog1 grew no tumors with cyclosporine alone. Using the four drug protocol, Dogs 2-6 grew abundant 1-2 mm intracapsular and 1-2 cm intraglandular tumors. Tumors grew >5 cm when the prostate cancer cells became extracapsular. Dogs 4-6 with sealed prostatic capsule implantation sites had growth of intracapsular and intraglandular tumors and LN metastases at 5 weeks. High tumor to background BPH signal in the NIRF images of sectioned prostate glands resulted from the 100 nmol dose (∼8 nmol/kg) in dogs 2-4 and 50 nmol dose in dog 5, but not from the 25 nmol dose in Dog 6. Imaging of mouse Ace-1huGRPr tumors required an intravenous dose of 500 nmol/kg body wt. A lymph node that drained the prostate gland was detectable in Dog 4. Histologic findings confirmed the imaging data.

CONCLUSION

Ace-1huGRPr cells created viable, huGRPr-expressing tumors when implanted orthotopically into immune-suppressed dogs. Local delivery of an imaging agent through the prostatic artery allowed a very low imaging dose, suggesting that therapeutic agents could be used safely for treatment of early localized intraglandular prostate cancer as adjuvant therapy for active surveillance or focal ablation therapies, or for treating multifocal intraglandular disease where focal ablation therapies are not indicated or ineffective.

Positive pre-biopsy MRI: are systematic biopsies still useful in addition to targeted biopsies?

PURPOSE

The diagnostic strategy implementing multiparametric magnet resonance tomography (mpMRI) and targeted biopsies (TB) improves the detection and characterization of significant prostate cancer (PCa). We aimed to assess the clinical usefulness of systematic biopsies (SB) in the setting of patients having a pre-biopsy positive MRI.

METHODS

A review of the literature was performed in March 2018. All studies investigating the performance of SB in addition to TB (all techniques) were assessed, both in the biopsy-naïve and repeat biopsy setting.

RESULTS

Evidence demonstrates that TB improves the detection of index-significant PCa compared with SB alone, in both initial and repeat biopsy settings. However, the combination of both TB and SB improved the overall (around 30%) and significant (around 10%) PCa detection rates as compared with TB alone. Significant differences between both biopsy approaches exist regarding cancer location favoring SB for the far lateral sampling, and TB for the anterior zone. Main current pitfalls of pure TB strategy are the learning curve and experience required for mpMRI reading and biopsy targeting, as well as the precision assessment in TB techniques.

CONCLUSION

A pure TB strategy omitting SB leads to the risk of missing up to 15% of significant cancer, due to limitations of mpMRI performance/reading and of precision during lesion targeting. SB remain necessary, in addition to the TB, to obtain the most accurate assessment of the entire prostate gland in this sub-group of patients at risk of significant disease.

Defining the target prior to prostate fusion biopsy: the effect of MRI reporting on cancer detection

PURPOSE

Definition of targets in multiparametric MRI (mpMRI) prior to MRI/TRUS fusion prostate biopsy either by urologist or radiologist, as a prose report or by illustration is crucial for accurate targeted biopsies (TB). The objective was to analyze the effect of MRI reporting on target definition and cancer detection.

METHODS

202 patients underwent MRI/TRUS fusion biopsy with Artemis™ (Eigen, USA). mpMRI results were submitted in written form to urologists, who marked the targets in the proprietary software. An expert uroradiologist reviewed and marked mpMRI targets blinded to biopsy data. We compared number, localization and volume of targets between the observers and analyzed whether variations impaired TB results by bivariate and logistic regression models.

RESULTS

Interobserver variability was moderate regarding number and low regarding localization of targets. Urologists overestimated target volumes significantly compared to radiologists (p = 0.045) and matching target volume between both observers was only 43.9%. Overall cancer detection rate was 69.8 and 52.0% by TB. A higher matching target volume was a significant predictor of cancer in TB (p < 0.001). Logistic regression revealed prostate volume and PI-RADS as independent predictors. Defining targets in incorrect T2w slices in the cranio-caudal axis are one presumable reason for missing cancer in TB.

CONCLUSIONS

A high concordance of the target definition between radiologist and urologist is mandatory for accurate TB. Optimized ROI definition is recommended to improve TB results, preferably as contouring in MRI sequences by the radiologist or, if not feasible, by precise MRI reports including specific localization in sequence and slice as well as an illustration. High prostate volume and low PI-RADS score have to be considered as limiting factors for target definition.

National implementation of multi-parametric magnetic resonance imaging for prostate cancer detection - recommendations from a UK consensus meeting

OBJECTIVES

To identify areas of agreement and disagreement in the implementation of multi-parametric magnetic resonance imaging (mpMRI) of the prostate in the diagnostic pathway.

MATERIALS AND METHODS

Fifteen UK experts in prostate mpMRI and/or prostate cancer management across the UK (involving nine NHS centres to provide for geographical spread) participated in a consensus meeting following the Research and Development Corporation and University of California-Los Angeles (UCLA-RAND) Appropriateness Method, and were moderated by an independent chair. The experts considered 354 items pertaining to who can request an mpMRI, prostate mpMRI protocol, reporting guidelines, training, quality assurance (QA) and patient management based on mpMRI levels of suspicion for cancer. Each item was rated for agreement on a 9-point scale. A panel median score of ≥7 constituted 'agreement' for an item; for an item to reach 'consensus', a panel majority scoring was required.

RESULTS

Consensus was reached on 59% of items (208/354); these were used to provide recommendations for the implementation of prostate mpMRI in the UK. Key findings include prostate mpMRI requests should be made in consultation with the urological team; mpMRI scanners should undergo QA checks to guarantee consistently high diagnostic quality scans; scans should only be reported by trained and experienced radiologists to ensure that men with unsuspicious prostate mpMRI might consider avoiding an immediate biopsy.

CONCLUSIONS

Our consensus statements demonstrate a set of criteria that are required for the practical dissemination of consistently high-quality prostate mpMRI as a diagnostic test before biopsy in men at risk.

Beyond transrectal ultrasound-guided prostate biopsies: available techniques and approaches

OBJECTIVES

Recent advances have led to the use of magnetic resonance imaging (MRI) alone or with fusion to transrectal ultrasound (TRUS) images for guiding biopsy of the prostate. Our group sought to develop consensus recommendations regarding MRI-guided prostate biopsy based on currently available literature and expert opinion.

METHODS

The published literature on the subject of MRI-guided prostate biopsy was reviewed using standard search terms and synthesized and analyzed by four different subgroups from among the authors. The literature was grouped into four categories-MRI-guided biopsy platforms, robotic MRI-TRUS fusion biopsy, template mapping biopsy and transrectal MRI-TRUS fusion biopsy. Consensus recommendations were developed using the Oxford Center for Evidence Based Medicine criteria.

RESULTS

There is limited high level evidence available on the subject of MRI-guided prostate biopsy. MRI guidance with or without TRUS fusion can lead to fewer unnecessary biopsies, help identify high-risk (Gleason ≥ 3 + 4) cancers that might have been missed on standard TRUS biopsy and identify cancers in the anterior prostate. There is no apparent significant difference between MRI biopsy platforms. Template mapping biopsy is perhaps the most accurate method of assessing volume and grade of tumor but is accompanied by higher incidence of side effects compared to TRUS biopsy.

CONCLUSIONS

Magnetic resonance imaging-guided biopsies are feasible and better than traditional ultrasound-guided biopsies for detecting high-risk prostate cancer and anterior lesions. Judicious use of MRI-guided biopsy could enhance diagnosis of clinically significant prostate cancer while limiting diagnosis of insignificant cancer.

Anterior Localization of Prostate Cancer Suspicious Lesions in 1,161 Patients Undergoing Magnetic Resonance Imaging/Ultrasound Fusion Guided Targeted Biopsies

PURPOSE

Based on findings in transrectal ultrasound guided biopsy series standard sampling of the prostate targets the posterior/peripheral zone. However, a substantial proportion of lesions that are prostate cancer suspicious and PI-RADS™ (Prostate Imaging Reporting and Data System) 3 or greater on magnetic resonance imaging is located in the anterior segment of the prostate, requiring deeper placement and targeting of the biopsy needle.

MATERIALS AND METHODS

Overall 1,161 patients underwent magnetic resonance imaging/ultrasound fusion guided targeted biopsy. Prostate cancer suspicious lesions on magnetic resonance imaging were dichotomized into anterior vs posterior prostate segments. Patients were stratified by the number of prior negative systematic biopsy sessions. Descriptive statistics included the frequency and proportion of multiparametric magnetic resonance imaging findings and corresponding histological results.

RESULTS

Targeted biopsy was performed in 513 patients (44%) who were systematic biopsy naïve, 396 (34%) with 1 prior negative systematic biopsy and 252 (22%) with 2 or more prior negative systematic biopsies. When patients were stratified by the number of prior systematic biopsy sessions, the proportion with exclusively anterior, PI-RADS 3 or greater lesions on magnetic resonance imaging increased from 3.5% to 9.1% (p = 0.006). Unfavorable 3 + 4 and 4 + 3 or greater primary Gleason patterns were identified in exclusively anterior vs posterior lesions in 31% vs 21% of the 448 patients, of whom 64 had exclusively anterior and 384 had posterior PI-RADS 3 or greater lesions, respectively, on magnetic resonance imaging. Multivariable logistic regression analyses confirmed these findings.

CONCLUSIONS

After multiple previous negative systematic biopsy sessions the proportion of anterior lesions on magnetic resonance imaging increased. Such lesions harbored a greater amount of unfavorable prostate cancer. Therefore, image guidance for precise targeting should be considered, especially after initially negative transrectal ultrasound guided systematic biopsy.

The Institutional Learning Curve of Magnetic Resonance Imaging-Ultrasound Fusion Targeted Prostate Biopsy: Temporal Improvements in Cancer Detection in 4 Years

PURPOSE

While magnetic resonance imaging-ultrasound fusion targeted biopsy allows for improved detection of clinically significant prostate cancer, a concerning amount of clinically significant disease is still missed. We hypothesized that a number of these misses are due to the learning curve associated with magnetic resonance imaging-ultrasound fusion targeted biopsy. We report the results of repeat magnetic resonance imaging-ultrasound fusion targeted biopsy in men with continued suspicion for cancer and the institutional learning curve in the detection of clinically significant prostate cancer with time.

MATERIALS AND METHODS

We analyzed the records of 1,813 prostate biopsies in a prospectively acquired cohort of men who presented for prostate biopsy in a 4-year period. All men were offered prebiopsy magnetic resonance imaging and were assigned a maximum PI-RADS™ (Prostate Imaging Reporting and Data System version 2) score. Biopsy outcomes in men with a suspicious region of interest were compared. The relationship between time and clinically significant prostate cancer detection was analyzed.

RESULTS

The clinically significant prostate cancer detection rate increased 26% with time in men with a PI-RADS 4/5 region of interest. On repeat magnetic resonance imaging-ultrasound fusion targeted biopsy in men with continued suspicion for cancer 53% of those with a PI-RADS 4/5 region of interest demonstrated clinically significant discordance from the initial magnetic resonance imaging-ultrasound fusion targeted biopsy compared to only 23% with a PI-RADS 1/2 region of interest. Significantly less clinically significant prostate cancer was missed or under graded in the most recent biopsies compared to the earliest biopsies.

CONCLUSIONS

The high upgrade rate on repeat magnetic resonance imaging-ultrasound fusion targeted biopsy and the increasing cancer detection rate with time show the significant learning curve associated with magnetic resonance imaging-ultrasound fusion targeted biopsy. Men with low risk or negative biopsies with a persistent, concerning region of interest should be promptly rebiopsied. Improved targeting accuracy with operator experience can help decrease the number of missed cases of clinically significant prostate cancer.

Is magnetic resonance imaging-targeted biopsy a useful addition to systematic confirmatory biopsy in men on active surveillance for low-risk prostate cancer? A systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyse evidence regarding the additional value of magnetic resonance imaging (MRI) and MRI-targeted biopsies to confirmatory systematic biopsies in identifying high-grade prostate cancer in men with low-risk disease on transrectal ultrasonography (TRUS) biopsy, as active surveillance (AS) of prostate cancer is recommended for men with Gleason 3 + 3 on standard TRUS-guided biopsy. Confirmatory assessment can include repeat standard TRUS-guided biopsy, and/or MRI with targeted biopsy when indicated.

METHODS

A systematic review of the Embase, Medline, Web-of-science, Google scholar, and Cochrane library was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Identified reports were critically appraised according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 criteria. Studies reporting men with Gleason 3 + 3 prostate cancer who had chosen AS based on transrectal systematic biopsy findings and had undergone MRI with systematic ± targeted biopsy at confirmatory assessment were included. The primary outcome was detection of any Gleason pattern ≥4.

RESULTS

Included reports (six) of men on AS (n = 1 159) showed cancer upgrading (Gleason ≥3 + 4) in 27% (95% confidence interval [CI] 22-34%) using a combined approach of MRI-targeted biopsies and confirmatory systematic biopsies. MRI-targeted biopsies alone would have missed cancer upgrading in 10% (95% CI 8-14%) and standard biopsies alone would have missed cancer upgrading in 7% (95% CI 5-10%). No pathway was more favourable than the other (relative risk [RR] 0.92, 95% CI 0.79-1.06). In all, 35% (95% CI 27-43%) of men with a positive MRI were upgraded, compared to 12% (95% CI 8-18%) of men with a negative MRI being upgraded (RR 2.77, 95% CI 1.76-4.38).

CONCLUSIONS

A pre-biopsy MRI should be performed before confirmatory systematic TRUS-guided biopsies in men on AS, together with MRI-targeted biopsies when indicated. A combined approach maximises cancer detection, although other factors within multivariate risk prediction can be used to aid the decision to biopsy in these men.

MR-Guided Prostate Interventions

Prostate cancer is the most commonly diagnosed noncutaneous cancer and second leading cause of death in men. Many patients with clinically organ-confined prostate cancer undergo definitive treatment of the whole gland, including radical prostatectomy, radiation therapy, and cryosurgery. Active surveillance is a growing alternative option for patients with documented low-volume and low-grade prostate cancer. However, many patients are wanting a less morbid focal treatment alternative. With recent advances in software and hardware of magnetic resonance imaging (MRI), multiparametric MRI of the prostate has been shown to improve the accuracy in detecting and characterizing clinically significant prostate cancer. Targeted biopsy is increasingly utilized to improve the yield of MR detected, clinically significant prostate cancer and to decrease in detection of indolent prostate cancer. MR-guided targeted biopsy techniques include cognitive MR fusion transrectal ultrasound (TRUS) biopsy, in-bore transrectal targeted biopsy using robotic transrectal device, and in-bore direct MR-guided transperineal biopsy with a software based transperineal grid template. In addition, advances in MR-compatible thermal ablation technology allow accurate focal or regional delivery of thermal ablative energy to the biopsy-proved, MRI-detected tumor. MR-guided ablative treatment options include cryoablation, laser ablation, and high-intensity focused ultrasound with real-time or near simultaneous monitoring of the ablation zone. We present a contemporary review of MR-guided techniques for prostatic interventions.

Assessment of the Diagnostic Accuracy of Biparametric Magnetic Resonance Imaging for Prostate Cancer in Biopsy-Naive Men: The Biparametric MRI for Detection of Prostate Cancer (BIDOC) Study

IMPORTANCE

Multiparametric magnetic resonance imaging (MRI) enhances detection and risk stratification for significant prostate cancer but is time-consuming (approximately 40 minutes) and expensive. Rapid and simpler (approximately 15-minute) biparametric MRI (bpMRI) using fewer scan sequences could be implemented as a prostate MRI triage test on a larger scale before performing biopsies.

OBJECTIVES

To assess the diagnostic accuracy and negative predictive value (NPV) of a novel bpMRI method in biopsy-naive men in detecting and ruling out significant prostate cancer in confirmatory biopsies.

DESIGN, SETTING, AND PARTICIPANTS

A single-institutional, paired, prospective cohort study of biopsy-naive men with clinical suspicion of prostate cancer from November 1, 2015, to June 15, 2017.

INTERVENTIONS

All patients underwent bpMRI (T2-weighted and diffusion-weighted imaging) followed by standard transrectal ultrasound-guided biopsies (all men) and targeted biopsies of men with suspicious bpMRI findings.

MAIN OUTCOMES AND MEASURES

Suspicion grades of bpMRI, biopsy results, and NPV of bpMRI were evaluated for detection of or ruling out significant prostate cancer (Gleason score ≥4 + 3 or maximum cancerous core length >50% for Gleason score 3 + 4). We compared the diagnostic performance of standard biopsies in all men vs standard plus targeted (combined) biopsies restricted to men with suspicious bpMRI findings. The reference standard was combined biopsy results from all men.

RESULTS

A total of 1020 men were enrolled, with a median age of 67 years (interquartile range, 61-71 years) and a median prostate-specific antigen level of 8.0 ng/mL (interquartile range, 5.7-13.0 ng/mL). Combined biopsies detected any and significant prostate cancer in 655 of 1020 men (64%) and 404 of 1020 men (40%), respectively. Restricting combined biopsies to men with suspicious bpMRI findings meant 305 of 1020 men (30%) with low-suspicious bpMRIs could avoid prostate biopsies (biopsy in 715 men with suspicious bpMRIs vs all 1020 men who required standard biopsies [70%]; P < .001). Significant prostate cancer diagnoses were improved by 11% (396 vs 351 men; P < .001), and insignificant prostate cancer diagnoses were reduced by 40% (173 vs 288 men; P < .001) compared with our current diagnostic standard, standard biopsies alone in all men. The NPV of bpMRI findings in ruling out significant prostate cancer was 97% (95% CI, 95%-99%).

CONCLUSIONS AND RELEVANCE

Low-suspicion bpMRI has a high NPV in ruling out significant prostate cancer in biopsy-naive men. Using a simple and rapid bpMRI method as a triage test seems to improve risk stratification and may be used to exclude aggressive disease and avoid unnecessary biopsies with its inherent risks. Future studies are needed to fully explore its role in clinical prostate cancer management.

Validation of Prostate Imaging Reporting and Data System Version 2 for the Detection of Prostate Cancer

PURPOSE

The second version of the PI-RADS™ (Prostate Imaging Reporting and Data System) was introduced in 2015 to standardize the interpretation and reporting of prostate multiparametric magnetic resonance imaging. Recently low cancer detection rates were reported for PI-RADS version 2 category 4 lesions. Therefore the aim of the study was to evaluate the cancer detection rate of PI-RADS version 2 in a large prospective cohort.

MATERIALS AND METHODS

The study included 704 consecutive men with primary or prior negative biopsies who underwent magnetic resonance imaging/ultrasound fusion guided targeted biopsy and 10-core systematic prostate biopsy between September 2015 and May 2017. All lesions were rated according to PI-RADS version 2 and lesions with PI-RADS version 2 category 3 or greater were biopsied. An ISUP (International Society of Urological Pathology) score of 2 or greater (ie Gleason 3 + 4 or greater) was defined as clinically significant prostate cancer.

RESULTS

The overall cancer detection rate of PI-RADS version 2 categories 3, 4 and 5 was 39%, 72% and 91% for all prostate cancer, and 23%, 49% and 77% for all clinically significant prostate cancer, respectively. If only targeted biopsy had been performed, 59 clinically significant tumors (16%) would have been missed. The PI-RADS version 2 score was significantly associated with the presence of prostate cancer (p <0.001), the presence of clinically significant prostate cancer (p <0.001) and the ISUP grade (p <0.001).

CONCLUSIONS

PI-RADS version 2 is significantly associated with the presence of clinically significant prostate cancer. The cancer detection rate of PI-RADS version 2 category 4 lesions was considerably higher than previously reported. When performing targeted biopsy, the combination with systematic biopsy still provides the highest detection of clinically significant prostate cancer.

Adoption of Prebiopsy Magnetic Resonance Imaging for Men Undergoing Prostate Biopsy in the United States

OBJECTIVE

To assess adoption of prebiopsy prostate magnetic resonance imaging (MRI) in the United States and to evaluate factors associated with magnetic resonance imaging-guided prostate biopsy (MRI-Bx) use. Prior reports have shown improved cancer detection with MRI-Bx vs transrectal ultrasound-guided methods (transrectal ultrasound-guided biopsy [TRUS-Bx]). Population-based trends of their use and outcomes have not been previously characterized.

MATERIALS AND METHODS

Using private insurance claims (2009-2015), we identified men who underwent prostate biopsy. Exposures were biopsy year and geographic region defined by metropolitan statistical area. Outcomes included biopsy type (MRI-Bx, TRUS-Bx, or transperineal biopsy) based on procedure codes and cancer detection based on a new diagnosis for prostate cancer (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] 185). Hierarchical mixed-effects multivariable regression estimated odds of undergoing MRI-Bx.

RESULTS

We identified 241,681 men (mean age 57.5 ± 5.4 years) who underwent biopsy. The use of MRI-Bx rose rapidly (0.2% in 2009 to 6.5% in 2015, P <.001). Overall, 3429 men underwent MRI before biopsy, more commonly in metropolitan statistical areas (odds ratio 1.90, 95% confidence interval 1.66-2.19). In 2015, nearly 18% of men with prior negative biopsy underwent a prebiopsy MRI. Patients with prior negative biopsies were over 4 times more likely to use MRI guidance (vs no prior biopsies, odds ratio 4.63, 95% confidence interval 4.27-5.02) and had a greater chance of cancer detection with MRI-Bx (25.2%) vs TRUS-Bx (19.7%, P = .010).

CONCLUSION

Among men undergoing prostate biopsy, prebiopsy prostate MRI utilization was concentrated within urban areas and among patients with prior negative biopsies, where its use was associated with superior cancer detection compared with traditional TRUS-Bx.

Integration and Diagnostic Accuracy of 3T Nonendorectal coil Prostate Magnetic Resonance Imaging in the Context of Active Surveillance

OBJECTIVE

To evaluate the integration of 3T nonendorectal coil multiparametric prostate magnetic resonance imaging (mpMRI) at 2 high-volume practices that routinely use mpMRI in the setting of active surveillance.

MATERIALS AND METHODS

This was an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, and dual-institution retrospective cohort study. Subjects undergoing 3T mpMRI without endorectal coil at either study institution over a 13-month period (August 1, 2015-August 31, 2016) were selected based on predefined criteria: clinical T1/T2 Gleason 6 prostate cancer, prostate-specific antigen <15 ng/mL, ≥40 years old, mpMRI within 2 years of prostate biopsy, and Prostate Imaging Reporting and Data System (PI-RADS) v2 score assigned. Subjects surveilled for Gleason ≥3 + 4 prostate cancer were excluded. The primary outcome was detection of Gleason ≥3 + 4 prostate cancer on magnetic resonance-ultrasound fusion biopsy, standard biopsy, or prostatectomy within 6 months following mpMRI. Positive predictive values (PPVs) were calculated.

RESULTS

A total of 286 subjects (N = 193 from institution 1, N = 93 from institution 2) met the criteria. Most (87% [90 of 104]) with maximum PI-RADS v2 scores of 1-2 did not receive immediate biopsy or treatment and remained on active surveillance. Incidence and PPVs for PI-RADS v2 scores of ≥3 were the following: PI-RADS 3 (n = 57 [20%], PPV 21% [6 of 29]), PI-RADS 4 (n = 96 [34%], PPV 51% [39 of 77]), and PI-RADS 5 (n = 29 [13%], PPV 71% [20 of 28]). No Gleason ≥4 + 3 prostate cancer was identified for PI-RADS v2 scores of 1-3 (0 of 43 with histology). Following mpMRI and subsequent biopsy, 21% (61 of 286) of subjects were removed from active surveillance and underwent definitive therapy.

CONCLUSION

The 3T nonendorectal coil mpMRI has been integrated into the care of patients on active surveillance and effectively stratifies risk of Gleason ≥3 + 4 prostate cancer in this population.

MR-guided biopsy and focal therapy: new options for prostate cancer management

PURPOSE OF REVIEW

Options for prostate cancer management are rapidly expanding. The recent advent of MRI technology has led to guided prostate biopsies by radiologists working in-bore or by urologists using MR/US fusion technology. The resulting tumor visualization now provides the option of focal therapy. Currently available are highly directed energies - focused ultrasound (HIFU), cryotherapy, and laser - all offering the hope of curing prostate cancer with few side effects.

RECENT FINDINGS

MRI now enables visualization of many prostate cancers. MR/US fusion biopsy makes possible the targeted biopsy of suspicious lesions efficiently in the urology clinic. Several fusion devices are now commercially available. Focal therapy, a derivative of targeted biopsy, is reshaping the approach to treatment of some prostate cancers. Focal laser ablation, originally done in the MRI gantry (in-bore), promises to soon become feasible in a clinic setting (out-of-bore) under local anesthesia. Other focal therapy options, including HIFU and cryotherapy, are currently available. Herein are summarized outcomes data on focal therapy modalities.

SUMMARY

MRI-guided biopsy is optimizing prostate cancer diagnosis. Focal therapy, an outgrowth of guided biopsy, promises to become a well tolerated and effective approach to treating many men with prostate cancer while minimizing the risks of incontinence and impotence from radical treatment.

Anatomic and Molecular Imaging in Prostate Cancer

Prostate cancer is characterized by a complex set of heterogeneous disease states. This review aims to describe how imaging has been studied within each specific state. As physicians transition into an era of precision medicine, multiparametric magnetic resonance imaging (mpMRI) is proving to be a powerful tool leading the way for a paradigm shift in the diagnosis and management of localized prostate cancer. With further research and development, molecular imaging modalities will likely change the way we approach recurrent and metastatic disease. Given the range of possible oncological progression patterns, a thorough understanding of the underlying carcinogenesis, as it relates to imaging, is a requisite if we are to appropriately manage prostate cancer in future decades.

The combination of targeted and systematic prostate biopsies is the best protocol for the detection of clinically significant prostate cancer

OBJECTIVE

Compared with standard systematic transrectal ultrasound (TRUS)-guided biopsies (SBx), targeted biopsies (TBx) using magnetic resonance imaging (MRI)/TRUS fusion could increase the detection of clinically significant prostate cancer (PCa-s) and reduce non-significant PCa (PCa-ns). This study aimed to compare the performance of the two approaches.

MATERIALS AND METHODS

A prospective, single-center study was conducted on all consecutive patients with PCa suspicion who underwent prebiopsy multiparametric MRI (mpMRI) using the Prostate Imaging Reporting and Data System (PI-RADS). All patients underwent mpMRI/TRUS fusion TBx (two to four cores/target) using UroStation™ (Koelis, Grenoble, France) and SBx (10-12 cores) during the same session. PCa-s was defined as a maximal positive core length ≥4 mm or Gleason score ≥7.

RESULTS

The study included 191 patients (at least one suspicious lesion: PI-RADS ≥3). PCa was detected in 55.5% (106/191) of the cases. The overall PCa detection rate and the PCa-s detection rate were not significantly higher in TBx alone versus SBx (44.5% vs 46.1%, p = .7, and 38.2% vs 33.5%, p = .2, respectively). Combined TBx and SBx diagnosed significantly more PCa-s than SBx alone (45% vs 33.5%, p = .02). PCa-s was detected only by TBx in 12% of cases (23/191) and only by SBx in 7.3% (14/191). Gleason score was upgraded by TBx in 16.8% (32/191) and by SBx in 13.6% (26/191) of patients (p = .4).

CONCLUSIONS

The combination of TBx and SBx achieved the best results for the detection and prognosis of PCa-s. The use of SBx alone would have missed the detection of PCa-s in 12% of patients.

Multiparametric MRI Apparent Diffusion Coefficient (ADC) Accuracy in Diagnosing Clinically Significant Prostate Cancer

AIM

To evaluate the accuracy of multiparametric magnetic resonance imaging apparent diffusion coefficient (mpMRI ADC) in the diagnosis of clinically significant prostate cancer (PCa).

PATIENTS AND METHODS

From January 2016 to December 2016, 44 patients who underwent radical prostatectomy for PCa and mpMRI lesions suggestive of cancer were retrospectively evaluated at definitive specimen. The accuracy of suspicious mpMRI prostate imaging reporting and data system (PI-RADS ≥3) vs. ADC values in the diagnosis of Gleason score ≥7 was evaluated.

RESULTS

Receiver operating characteristics (ROC) curve analysis gave back an ADC threshold of 0.747×10^-3 mm²/s to separate between Gleason Score 6 and ≥7. The diagnostic accuracy of ADC value (cut-off 0.747×10^-3 mm²/s) vs. PI-RADS score ≥3 in diagnosing PCa with Gleason score ≥7 was equal to 84% vs. 63.6% with an area under the curve (AUC) ROC of 0.81 vs. 0.71, respectively.

CONCLUSION

ADC evaluation could support clinicians in decision making of patients with PI-RADS score <3 at risk for PCa.

Transrectal ultrasound-guided prostate rebiopsy: How many core sampling should be applied to which patient?

Background:

We investigated the correlation between the sampled number of cores in rebiopsy and the cancer detection rate (CDR).

Materials and Methods:

Two hundred and twelve patients with normal rectal examination who had undergone rebiopsy in the past 5 years were examined retrospectively. Moreover, 68% of them had undergone 12 cores (Group 1) while 32% had undergone 20 cores (Group 2). Both groups were compared with respect to the CDR.

Results:

There was no difference between groups in terms of age, total prostate-specific antigen, and prostate volume (P > 0.05). Forty-one (19%) of 212 patients were diagnosed with cancer, and the CDR was significantly higher in Group 2 (30.9% vs. 13.9%, P = 0.004). This rate increased from 6.5% to 20% (P = 0.025) and from 0% to 33.3% (P = 0.023), respectively, with 12-core and 20-core rebiopsies in patients whose initial pathology indicated benign and high-grade prostatic intraepithelial neoplasia (HGPIN). Furthermore, cancer was detected in 24 (40%) of 60 patients who were diagnosed with atypical small acinar proliferation (ASAP) in the initial biopsy. However, despite being higher in 20-core biopsy group (47.6% vs. 35.9%), this was not statistically significant (P = 0.377).

Conclusions:

At least 20 cores should be sampled in rebiopsy, especially in the patients diagnosed with benign and HGPIN. However, we believe that standard systematic sampling will be sufficient for the patients diagnosed with ASAP.

Reduction of MRI-targeted biopsies in men with low-risk prostate cancer on active surveillance by stratifying to PI-RADS and PSA-density, with different thresholds for significant disease

Background

The fear of undergrading prostate cancer (PCa) in men on active surveillance (AS) have led to strict criteria for monitoring, which have resulted in good long-term cancer-specific survival, proving the safety of this approach. Reducing undergrading, MRI-targeted biopsies are increasingly used in men with low-risk disease despite their undefined role yet. The objective of this study is to investigate the rate of upgrading using MRI-targeted biopsies in men with low-risk disease on AS, stratified on the basis of PI-RADS and PSA-density, with the aim to reduce potential unnecessary repeat biopsy procedures.

Methods

A total of 331 men were prospectively enrolled following the MRI-PRIAS protocol. MR imaging was according to Prostate Imaging Reporting and Data System (PI-RADSv2) guidelines. Suspicious MRI lesions (PI-RADS 3–5) were additionally targeted by MRI-TRUS fusion biopsies. Outcome measure was upgrading to Gleason score (GS) ≥3+4 with MRI-targeted biopsies, stratified for PI-RADS and PSA-density.

Results

In total, 25% (82/331) of men on AS showed upgrading from GS 3+3. Only 3% (11/331) was upgraded to GS ≥8. In 60% (198/331) a suspicious MRI lesion was identified, but in only 41% (82/198) of men upgrading was confirmed. PI-RADS 3, 4 and 5 categorized index lesions, showed upgrading in 30%, 34% and 66% of men, respectively. Stratification to PI-RADS 4–5, instead of PI-RADS 3–5, would have missed a small number of high volume Gleason 4 PCa in PI-RADS 3 category. However, further stratification into PI-RADS 3 lesions and PSA-density <0.15 ng/mL² could result in a safe targeted biopsy reduction of 36% in this category, without missing any upgrades.

Conclusions

Stratification with the combination of PI-RADS and PSA-density may reduce unnecessary additional MRI biopsy testing. Overall, the high rate of detected upgrading in men on AS may result in an unintended tightening of continuing in AS. Since patients, included under current AS criteria showed extremely favorable outcome, there might be no need to further restrict continuing on AS with MRI and targeted biopsies.

Focal Therapy Eligibility Determined by Magnetic Resonance Imaging/Ultrasound Fusion Biopsy

PURPOSE

We assessed focal therapy eligibility in men who underwent multiparametric magnetic resonance imaging and targeted biopsy with correlation to whole mount histology after radical prostatectomy.

MATERIALS AND METHODS

Subjects were selected from among the 454 men in whom targeted biopsy proven prostate cancer was derived from regions of interest on multiparametric magnetic resonance imaging from 2010 to 2016. Focal therapy eligibility was limited to a maximum Gleason score of 4 + 3 in regions of interest with or without other foci of low risk prostate cancer (Gleason score 3 + 3 and less than 4 mm). Men who did not meet NCCN® intermediate risk criteria were classified as ineligible for focal therapy. Of the 454 men 64 underwent radical prostatectomy and biopsy findings were compared to final pathology findings.

RESULTS

Of the 454 men with a biopsy proven region of interest 175 (38.5%) were eligible for focal therapy. Fusion biopsy, which combined targeted and template biopsy, had 80.0% sensitivity (12 of 15 cases), 73.5% specificity (36 of 49) and 75.0% accuracy (48 of 64) for focal therapy eligibility. Targeted cores alone yielded 73.3% sensitivity (11 of 15 cases), 47.9% specificity (23 of 48) and 54.7% accuracy (35 of 64). Gleason score and extension across the midline differed in 4 and 9, respectively, of the 13 cases that showed discordant biopsy and whole mount histology.

CONCLUSIONS

Using intermediate risk eligibility criteria more than a third of men with a targeted biopsy proven lesion identified on multiparametric magnetic resonance imaging would have been eligible for focal therapy. Eligibility determined by fusion biopsy was concordant with whole mount histology in 75% of cases. Improved selection criteria are needed to reliably determine focal therapy eligibility.

MRI in early prostate cancer detection: how to manage indeterminate or equivocal PI-RADS 3 lesions?

This review focuses on indeterminate lesions on prostate magnetic resonance imaging (MRI), assigned as PI-RADS category 3. The prevalence of PI-RADS 3 index lesion in the diagnostic work-up is significant, varying between one in three (32%) to one in five (22%) men, depending on patient cohort of first biopsies, previously negative biopsies, and active surveillance biopsies. A management strategy must be developed for this group of men with an indeterminate suspicion of having clinically significant prostate cancer (csPCa). Currently available data show that the actual prevalence of csPCa after targeted biopsy in PI-RADS 3 lesions vary between patients groups from one in five (21%) to one in six (16%), depending on previous biopsy status. Although this prevalence is lower in comparison to PI-RADS 4 and PI-RADS 5 lesions, still a considerable proportion of men harbor significant disease. Men with such a PI-RADS 3 lesion should therefore be adequately managed. In general, the clinical approach of using a threshold of PI-RADS ≥4 instead of PI-RADS ≥3 to select MRI for targeted biopsies is not supported by data from our explorative literature search using current definitions of csPCa. A possible adaptation to the threshold of PI-RADS ≥4 in combination with other clinical markers could be considered within an active surveillance protocol, where the balance between the individual risk of missing csPCa and the constant process of repeating prostate biopsies is crucial. In the future, improvements in MR imaging and interpretation, combined with molecular biomarkers and multivariate risk models will all be employed in prostate cancer detection and monitoring. These combinations will aid decision-making in challenging circumstances, such as unclear and diagnostic equivocal results for csPCa at early detection.

Targeted Prostate Biopsy in the Era of Active Surveillance

Targeted prostate biopsy using magnetic resonance imaging (MRI) guidance is improving the accuracy of prostate cancer (CaP) diagnosis. This new biopsy technology is especially important for men undergoing active surveillance, improving patient selection for enrollment and enabling precise longitudinal monitoring. Magnetic resonance imaging/ultrasound fusion biopsy allows for 3 functions not previously possible with US-guided biopsy: targeting of suspicious regions, template-mapping for systematic sampling, and tracking of cancer foci over time. This article reviews the evolving role of the new biopsy methods in active surveillance, including the UCLA Active Surveillance pathway, which has incorporated magnetic resonance imaging/ultrasound fusion biopsy from program inception as a possible model.

MR Imaging-Guided Focal Treatment of Prostate Cancer: An Update

Focal treatment of prostate cancer has evolved from a concept to a practice in the recent few years and is projected to fill an existing need, bridging the gap between conservative and radical traditional treatment options. With its low morbidity and rapid recovery time compared with whole-gland treatment alternatives, focal therapy is poised to gain more acceptance among patients and health care providers. As our experience with focal treatment matures and evidence continues to accrue, the landscape of this practice might look quite different in the future.

Prediction of Prostate Cancer Risk Among Men Undergoing Combined MRI-targeted and Systematic Biopsy Using Novel Pre-biopsy Nomograms That Incorporate MRI Findings

OBJECTIVE

To develop nomograms that predict the probability of overall prostate cancer (PCa) and clinically significant PCa (Gleason ≥7) on magnetic resonance imaging (MRI)-targeted, and combined MRI-targeted and systematic, prostate biopsy.

MATERIALS AND METHODS

From June 2012 to August 2014, magnetic resonance imaging to ultrasound fusion-targeted prostate biopsy was performed on 464 men with suspicious regions identified on pre-biopsy 3T MRI along with systematic 12 core biopsy. Logistic regression modeling was used to evaluate predictors of overall and clinically significant PCa, and corresponding nomograms were generated for men who were not previously biopsied or had 1 or more prior negative biopsies. Models were created with 70% of a randomly selected training sample and bias-corrected using bootstrap resampling. The models were then validated with the remaining 30% testing sample pool.

RESULTS

A total of 459 patients were included for analysis (median age 66 years, prostate-specific antigen [PSA] 5.2 ng/mL, prostate volume 49 cc). Independent predictors of PCa on targeted and systematic prostate biopsy were PSA density, age, and MRI suspicion score. PCa probability nomograms were generated for each cohort using the predictors. Bias-corrected areas under the receiver-operating characteristic curves for overall and clinically significant PCa detection were 0.82 (0.78) and 0.91 (0.84) for men without prior biopsy and 0.76 (0.65) and 0.86 (0.87) for men with a prior negative biopsy in the training (testing) samples.

CONCLUSION

PSA density, age, and MRI suspicion score predict PCa on combined MRI-targeted and systematic biopsy. Our generated nomograms demonstrate high diagnostic accuracy and may further aid in the decision to perform biopsy in men with clinical suspicion of PCa.

Approach to the Patient with High-Risk Prostate Cancer

Men classified as having high-risk prostate cancer warrant treatment because durable outcomes can be achieved. Judicious use of imaging and considerations of risk factors are essential when caring for men with high-risk disease. Radical prostatectomy, radiation therapy, and androgen deprivation therapy all play pivotal roles in the management of men with high-risk disease, and potentially in men with metastatic disease. The optimal combinations of therapeutic regimens are an evolving area of study and future work looking into therapies for men with high-risk disease will remain critical.

Does magnetic resonance imaging-guided biopsy improve prostate cancer detection? A comparison of systematic, cognitive fusion and ultrasound fusion prostate biopsy

Background

The increase in the use of multiparametric magnetic resonance imaging for the detection of prostate cancer has led to the rapid adoption of MRI-guided biopsies (MRGBs). To date, there is limited evidence in the use of MRGB and no direct comparisons between the different types of MRGB. We aimed to assess whether multiparametric MRGBs with MRI-US transperineal fusion biopsy (FB) and cognitive biopsy (CB) improved the management of prostate cancer and to assess if there is any difference in prostate cancer detection with FB compared with CB.

Methods

Patients who underwent an MRGB and a systematic biopsy (SB) from June 2014 to August 2016 on the Central Coast, NSW, Australia, were included in the study. The results of SB were compared with MRGB. The primary outcome was prostate cancer detection and if MRGB changed patient management.

Results

A total of 121 cases were included with a mean age of 65.5 years and prostate-specific antigen 7.4 ng/mL. Seventy-five cases (62%) had a Prostate Imaging and Reporting Data System 4–5 lesions and 46 (38%) had a Prostate Imaging and Reporting Data System 3 lesions. Fifty-six cases underwent CB and 65 underwent FB.

Of the 93 patients with prostate cancer detected, 19 men (20.5%) had their management changed because of the MRGB results. Eight men (9%) had prostate cancer detected on MRGB only and 12 men (13%) underwent radical prostatectomy or radiotherapy based on the MRGB results alone.

There was a trend to a higher rate of change in management with FB compared with CB (29% vs. 18%).

Conclusions

This is one of the first Australian studies to assess the utility of MRGB and compare FB with CB. MRGB is a useful adjunct to SB, changing management in over 20% of our cases, with a trend toward FB having a greater impact on patient management compared with CB.

Multicentre evaluation of targeted and systematic biopsies using magnetic resonance and ultrasound image-fusion guided transperineal prostate biopsy in patients with a previous negative biopsy

OBJECTIVES

To evaluate the detection rates of targeted and systematic biopsies in magnetic resonance imaging (MRI) and ultrasound (US) image-fusion transperineal prostate biopsy for patients with previous benign transrectal biopsies in two high-volume centres.

PATIENTS AND METHODS

A two centre prospective outcome study of 487 patients with previous benign biopsies that underwent transperineal MRI/US fusion-guided targeted and systematic saturation biopsy from 2012 to 2015. Multiparametric MRI (mpMRI) was reported according to Prostate Imaging Reporting and Data System (PI-RADS) Version 1. Detection of Gleason score 7-10 prostate cancer on biopsy was the primary outcome. Positive (PPV) and negative (NPV) predictive values including 95% confidence intervals (95% CIs) were calculated. Detection rates of targeted and systematic biopsies were compared using McNemar's test.

RESULTS

The median (interquartile range) PSA level was 9.0 (6.7-13.4) ng/mL. PI-RADS 3-5 mpMRI lesions were reported in 343 (70%) patients and Gleason score 7-10 prostate cancer was detected in 149 (31%). The PPV (95% CI) for detecting Gleason score 7-10 prostate cancer was 0.20 (±0.07) for PI-RADS 3, 0.32 (±0.09) for PI-RADS 4, and 0.70 (±0.08) for PI-RADS 5. The NPV (95% CI) of PI-RADS 1-2 was 0.92 (±0.04) for Gleason score 7-10 and 0.99 (±0.02) for Gleason score ≥4 + 3 cancer. Systematic biopsies alone found 125/138 (91%) Gleason score 7-10 cancers. In patients with suspicious lesions (PI-RADS 4-5) on mpMRI, systematic biopsies would not have detected 12/113 significant prostate cancers (11%), while targeted biopsies alone would have failed to diagnose 10/113 (9%). In equivocal lesions (PI-RADS 3), targeted biopsy alone would not have diagnosed 14/25 (56%) of Gleason score 7-10 cancers, whereas systematic biopsies alone would have missed 1/25 (4%). Combination with PSA density improved the area under the curve of PI-RADS from 0.822 to 0.846.

CONCLUSION

In patients with high probability mpMRI lesions, the highest detection rates of Gleason score 7-10 cancer still required combined targeted and systematic MRI/US image-fusion; however, systematic biopsy alone may be sufficient in patients with equivocal lesions. Repeated prostate biopsies may not be needed at all for patients with a low PSA density and a negative mpMRI read by experienced radiologists.

Targeted 11C-choline PET-CT/TRUS software fusion-guided prostate biopsy in men with persistently elevated PSA and negative mpMRI after previous negative biopsy

Background

We evaluated the feasibility and accuracy of 11C–choline PET-CT/TRUS fusion-guided prostate biopsy in men with persistently elevated PSA and negative mpMRI or contraindication to MRI, after previous negative biopsy. Clinical data were part of a prospective on-going observational clinical study: “Diagnostic accuracy of target mpMRI/US fusion biopsy in patients with suspected prostate cancer after initial negative biopsy”. Patients with a negative biopsy and negative mpMRI (PI-RADS v.2 < 3) or absolute contraindications to MRI and persistently elevated PSA, were included. All patients underwent 11C–choline PET with dedicated acquisition of the pelvis and PET-CT/TRUS-guided prostate biopsy by Bio-Jet™ fusion system (D&K Technologies, Germany). The primary endpoint was to assess the accuracy of 11C–choline PET-CT to determine the presence and the topographical distribution of PCa.

Results

Overall, 15 patients (median age 71 yrs. ± 8.89; tPSA 13.5 ng/ml ± 4.3) were analysed. Fourteen had a positive PET scan, which revealed 30 lesions. PCa was detected in 7/15 patients (46.7%) and four patients presented a clinically significant PCa: GS > 6. Over 58 cores, 25 (43.1%) were positive. No statistically significant difference in terms of mean and median values for SUVmax and SUVratio between benign and malignant lesions was found. PCa lesions with GS 3 + 3 (n = 3) showed a median SUVmax and SUVratio of 4.01 and 1.46, compared to 5.45 and 1.57, respectively for lesions with GS >6 (n = 4).

Conclusion

Software PET-CT/TRUS fusion-guided target biopsy could be a diagnostic alternative in patients with a suspected primary PCa and negative mpMRI, but its specificity appeared low.

MRI/US fusion-guided biopsy: performing exclusively targeted biopsies for the early detection of prostate cancer

PURPOSE

The aim of this study was to validate the role of MR/Ultrasound Fusion-Guided Targeted Biopsy as a first diagnostic modality in subjects with clinical suspicion of prostate cancer (PCa).

MATERIALS AND METHODS

108 men (age range 46-78 years) with clinical suspicion for PCa (PSA > 4 ng/mL) underwent multiparametric MRI of the prostate (mpMRI) and, when suspicious lesion were found (according to the PIRADSv2 scoring system), targeted biopsy was performed. All patients without significant alteration patterns at mpMRI have been referred for follow-up at 1 year.

RESULTS

91/108 patients showed on the mpMRI highly suspicious lesions (PIRADS 4 and 5); the remaining 17/108 patients revealed no significant alteration consistent with PCa (PIRADS 3). Among the first group of patients, 58/91 proved to be positive for PCa on the pathology report: 24 patients had a Gleason Score (GS) 6 (3 + 3); 18 patients GS 7 of which 7 (3 + 4) and 11 (4 + 3); 14 patients GS 8 (4 + 4); two patients GS 9 (5 + 4); 33 proved to be negative. Overall cancer detection rate (CDR) was 63%. However, the CDR rises significantly, up to 77%, after the 53 initial consecutive biopsies that were performed (p < 0,05) and thus identified as part of the learning curve. Patients of the second group (17/108) have been followed with serial PSA assessments, clinical reevaluation, and follow-up mpMRI.

CONCLUSION

Performing exclusively targeted MR/Ultrasound Fusion-Guided biopsies for the diagnosis of PCa in patients with suspicious PSA levels (> 4 ng/mL) increases the detection rate of clinically significant cancer, changing both the therapeutic options and the prognosis.

Multimodality Image Fusion with PSMA PET/CT and High-Intensity Focused Ultrasound Focal Therapy for Primary Diagnosis and Management of Prostate Cancer: A Planned Research Initiative

Recent developments in diagnostic imaging herald a new approach to diagnosis and management of prostate cancer. Multimodality fusion that combines anatomic with functional imaging data has surpassed either of the two alone. This opens up the possibility to "find and fix" malignancy with greater accuracy than ever before. This is particularly important for prostate cancer because it is the most common male cancer in most developed countries. This article describes technical advances under investigation at our institution and others using multimodality image fusion of magnetic resonance imaging (MRI), transrectal ultrasound (TRUS), and PSMA PET/CT (defined as the combination of prostate-specific membrane antigen [PSMA], positron emission tomography [PET], and computed tomography [CT]) for personalized medicine in the diagnosis and focal therapy of prostate cancer with high-intensity focused ultrasound (HiFUS).

Prospective comparison of transperineal magnetic resonance imaging/ultrasonography fusion biopsy and transrectal systematic biopsy in biopsy-naïve patients

OBJECTIVES

To evaluate the value of multiparametric magnetic resonance imaging (mpMRI) in the detection of significant prostate cancer (PCa) and to compare transperineal MRI/ultrasonography fusion biopsy (fusPbx) with conventional transrectal systematic biopsy (sysPbx) in biopsy-naïve patients.

PATIENTS AND METHODS

This multicentre, prospective trial investigated biopsy-naïve patients with suspicion of PCa undergoing transperineal fusPbx in combination with transrectal sysPbx (comPbx). The primary outcome was the detection of significant PCa, defined as Gleason pattern 4 or 5. We analysed the results after a study period of 2 years.

RESULTS

The study included 214 patients. The median (range) number of targeted and systematic cores was 6 (2-15) and 12 (6-18), respectively. The overall PCa detection rate of comPbx was 52%. FusPbx detected more PCa than sysPbx (47% vs 43%; P = 0.15). The detection rate of significant PCa was 38% for fusPbx and 35% for sysPbx (P = 0.296). The rate of missed significant PCa was 14% in fusPbx and 21% in sysPbx. ComPbx detected significantly more significant PCa than fusPbx and sysPbx alone (44% vs 38% vs 35%; P < 0.005). In patients presenting with Prostate Imaging Reporting and Data System (PI-RADS) 4 and 5 lesions there was a higher detection rate of significant PCa than in patients presenting with PI-RADS ≤3 lesions in comPbx (61% vs 14%; P < 0.005).

CONCLUSIONS

For biopsy-naïve men with tumour-suspicious lesions in mpMRI, the combined approach outperformed both fusPbx and sysPbx in the detection of overall PCa and significant PCa. Thus, biopsy-naïve patients may benefit from sysPbx in combination with mpMRI targeted fusPbx.

Validation of Prostate Imaging-Reporting and Data System Version 2: A Retrospective Analysis

PURPOSE

Use of magnetic resonance imaging (MRI)/transrectal ultrasound fusion biopsies to determine the accuracy of multiparametric MRI (mpMRI), using Prostate Imaging-Reporting and Data System version 2 (PI-RADSv2), for detecting clinically significant prostate cancer in the overall gland and specifically the peripheral zone (PZ) and transitional zone (TZ).

METHODS

A retrospective analysis of patients who underwent fusion biopsy identified 137 men with 231 prostate lesions was approved by the Institutional Review Board. Subjects initially classified under PI-RADSv1 criteria were regraded using PI-RADSv2 by a radiologist blinded to PI-RADSv1 score and biopsy results. Spearman correlation, chi-squared, and logistic regression analysis were performed.

RESULTS

There was positive correlation between PI-RADSv2 and Gleason scores (P < 0.001). In the PZ, mpMRI demonstrated 100% sensitivity, 100% negative predictive value, and 35.9% positive predictive value, compared to 100%, 100%, and 27.1%, respectively, for TZ lesions. When predicting clinically significant prostate cancer, the PI-RADSv2 area under the curve for TZ lesions was 0.844 (95% CI: 0.753-0.935, P < 0.001) and 0.769 (95% CI: 0.684-0.854, P < 0.001) for PZ lesions. Combining PI-RADSv2 with additional risk factors (body mass index, prostate-specific antigen density, digital rectal examination) improved the area under curve.

CONCLUSIONS

PI-RADSv2 achieves excellent sensitivity and negative predictive value for both PZ and TZ lesions.

The Influence of Serum Prostate-Specific Antigen on the Accuracy of Magnetic Resonance Imaging Targeted Biopsy versus Saturation Biopsy in Patients with Previous Negative Biopsy

Objective

We compared the prostate cancer (PCa) detection rates of targeted biopsy (TB) and saturation biopsy (SB) in patients with previous negative biopsy and the accuracy of TB and SB stratified by different serum prostate-specific antigen (PSA) levels.

Materials and Methods

Overall 185 patients were enrolled. In the magnetic resonance imaging (MRI) group, 65 men underwent TB and SB. In the control group, 120 men underwent SB alone. The primary outcome was the difference in PCa detection rate between the MRI group and control group. The secondary outcome was the difference in accuracy between TB and SB in detecting clinically significant PCa by stratifying the patients in the MRI group into those with PSA < 10 ng/ml and PSA ≥ 10 ng/ml.

Results

The detection rates for overall and clinically significant PCa were higher in the MRI group than in the control group (46.2% versus 20.9% and 43.1% versus 16.7%, both p < 0.001). In the MRI group, the accuracy of TB was higher than SB (94.7% versus 84.2%, p = 0.001) for the patients with PSA ≥ 10 ng/mL.

Conclusions

Combining TB and SB achieved the best cancer detection rate. The accuracy of TB was better than SB in the patients with serum PSA ≥ 10 ng/mL.

Association between a 17-gene genomic prostate score and multi-parametric prostate MRI in men with low and intermediate risk prostate cancer (PCa)

Background

We aimed to directly compare results from multi-parametric prostate MRI (mpMRI) and a biopsy-based 17-gene RT-PCR assay providing a Genomic Prostate Score (GPS) among individuals who were candidates for active surveillance with low and intermediate risk prostate cancer (PCa).

Patients and methods

We evaluated the association between GPS results (scale 0–100) and endorectal mpMRI findings in men with clinically localized PCa. MR studies were reviewed to a five-tier scale of increasing suspicion of malignancy. Mean apparent diffusion coefficient (ADC) was calculated from a single dominant lesion. Mean rank of the GPS (0–100) among MRI strata was compared with the Kruskal-Wallis test and Dunn's multiple comparison test. Spearman's correlation was performed to examine the association between mean ADC and scaled GPS.

Results

Of 186 patients who received GPS testing, 100 were identified who received mpMRI. Mean GPS results differed between mpMRI categories (p = 0.001); however a broad range was observed in all mpMRI categories. Among men with biopsy Gleason pattern 3+3, mean GPS results were not significantly different among MRI groups (p = 0.179), but GPS differences were seen among MRI categories for patients with pattern 3+4 (p = 0.010). Mean ADC was weakly associated with GPS (σ = -0.151). Stromal response (p = 0.015) and cellular organization (p = 0.045) gene group scores differed significantly by MRI findings, but no differences were seen among androgen signaling or proliferation genes.

Conclusions

Although a statistically significant association was observed between GPS results and MRI scores, a wide range of GPS values were observed across imaging categories suggesting that mpMRI and genomic profiling may offer non- overlapping clinical insights.