Magnetic Resonance Imaging/Transrectal Ultrasonography Fusion Prostate Biopsy Significantly Outperforms Systematic 12-Core Biopsy for Prediction of Total Magnetic Resonance Imaging Tumor Volume in Active Surveillance Patients

Role of multi-parametric magnetic resonance imaging fusion biopsy in active surveillance of prostate cancer: a systematic review

Background:

Our goal is to review current literature regarding the role of multi-parametric magnetic resonance imaging (mpMRI) in the active surveillance (AS) of prostate cancer (PCa) and identify trends in rate of reclassification of risk category, performance of fusion biopsy (FB) versus systematic biopsy (SB), and progression-free survival.

Methods:

We performed a comprehensive literature search in PubMed and identified 121 articles. A narrative summary was performed.

Results:

Thirty-two articles were chosen to be featured in this review. SB and FB are complementary in detecting higher-grade disease in follow-up. While FB was more likely than SB to detect clinically significant disease, FB missed 6.4–11% of clinically significant disease. Imaging factors that predicted upgrading include number of lesions on magnetic resonance imaging (MRI), lesion density, and MRI suspicion level.

Conclusion:

Incorporating mpMRI FB in conjunction with SB should be part of contemporary AS protocols. mpMRI should additionally be used routinely for follow-up; however, mpMRI is not currently sensitive enough in detecting disease progression to replace biopsy in the surveillance protocol.

Development of a transperineal prostate biopsy robot guided by MRI-TRUS image

BACKGROUND

In the transrectal ultrasound (TRUS)-guided transperineal prostate biopsy, doctors determine the biopsy target by observing the prostate region in TRUS images. However, ultrasound images with low imaging quality make doctors easy to be interfered when determining the biopsy route, which reduces the biopsy success rate.

METHODS

This paper introduces the guidance method of magnetic resonance image (MRI) registration to ultrasound image and develops a 5-degrees of freedom robot for prostate biopsy guided by MRI-TRUS image. The robot uses a structure attached to the ultrasound probe to reduce the space occupied. By registering the posture relationship between MRI, TRUS image, ultrasonic probe and the robot base, the accurate localization of the suspected lesion area can be achieved with the preoperative MRIs.

RESULTS

The prostate phantom biopsy based on the robotic biopsy system in this paper, the average biopsy error is 1.44 mm, and the maximum biopsy error is 2.23 mm.

CONCLUSIONS

We build a robotic biopsy platform with prostate phantom, and evaluate the biopsy accuracy of MRI-TRUS guided prostate biopsy robot, the results meet clinical prostate biopsy requirements.

Update on Multiparametric Prostate MRI During Active Surveillance: Current and Future Trends and Role of the PRECISE Recommendations

Active surveillance for low-to-intermediate risk prostate cancer is a conservative management approach that aims to avoid or delay active treatment until there is evidence of disease progression. In recent years, multiparametric MRI (mpMRI) has been increasingly used in active surveillance and has shown great promise in patient selection and monitoring. This has been corroborated by publication of the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation (PRECISE) recommendations, which define the ideal reporting standards for mpMRI during active surveillance. The PRECISE recommendations include a system that assigns a score from 1 to 5 (the PRECISE score) for the assessment of radiologic change on serial mpMRI scans. PRECISE scores are defined as follows: a score of 3 indicates radiologic stability, a score of 1 or 2 denotes radiologic regression, and a score of 4 or 5 indicates radiologic progression. In the present study, we discuss current and future trends in the use of mpMRI during active surveillance and illustrate the natural history of prostate cancer on serial scans according to the PRECISE recommendations. We highlight how the ability to classify radiologic change on mpMRI with use of the PRECISE recommendations helps clinical decision making.

Magnetic resonance imaging/transrectal ultrasonography fusion guided seed placement in a phantom: Accuracy between 2-seed versus 1-seed strategies

PURPOSE

To investigate whether the 2-seed placement per Magnetic Resonance Imaging (MRI) suspicious lesion yields a higher seed placement accuracy than a 1-seed strategy on a phantom.

METHODS

Eight olives embedded in gelatin, each simulating a prostate, underwent MRI. Three virtual spherical lesions (3, 5, and 8 mm diameters) were marked in each olive on the MRI images and co-registered to the MRI/Transrectal Ultrasonography (TRUS) fusion biopsy system. Two radiologists placed 0.5 mm fiducials, targeting the center of each virtual lesion under fusion image guidance. Half of the 8 olives in each phantom were assigned either to the 1-seed or 2-seeds per lesion strategy. Post-procedure Computed Tomography (CT) images identified each seed and were fused with MR to localize each virtual lesion and collected the seed placement error - distance between the virtual target and the corresponding seed (using the closer seed for the 2-seed strategy). Seed placement success is defined as fiducial placement within a lesion boundary.

RESULTS

Each operator repeated the procedure on three different phantoms, and data from 209 seeds placed for 137 lesions were analyzed, with an overall error of 3.03 ± 1.52 mm. The operator skill, operator phantom procedural experience, lesion size, and number of seeds, were independently associated with the seed placement error. Seed placement success rate was higher for the 2-seed group compared to 1-seed, although the difference was not statistically significant.

CONCLUSIONS

Placing 2 seeds per MRI lesion yielded a significantly lower error compared to 1-seed strategy, although seed placement success rate was not significantly different.

Update of the Standard Operating Procedure on the Use of Multiparametric Magnetic Resonance Imaging for the Diagnosis, Staging and Management of Prostate Cancer

PURPOSE

We update the prior standard operating procedure for magnetic resonance imaging of the prostate, and summarize the available data about the technique and clinical use for the diagnosis and management of prostate cancer. This update includes practical recommendations on the use of magnetic resonance imaging for screening, diagnosis, staging, treatment and surveillance of prostate cancer.

MATERIALS AND METHODS

A panel of clinicians from the American Urological Association and Society of Abdominal Radiology with expertise in the diagnosis and management of prostate cancer evaluated the current published literature on the use and technique of magnetic resonance imaging for this disease. When adequate studies were available for analysis, recommendations were made on the basis of data and when adequate studies were not available, recommendations were made on the basis of expert consensus.

RESULTS

Prostate magnetic resonance imaging should be performed according to technical specifications and standards, and interpreted according to standard reporting. Data support its use in men with a previous negative biopsy and ongoing concerns about increased risk of prostate cancer. Sufficient data now exist to support the recommendation of magnetic resonance imaging before prostate biopsy in all men who have no history of biopsy. Currently, the evidence is insufficient to recommend magnetic resonance imaging for screening, staging or surveillance of prostate cancer.

CONCLUSIONS

Use of prostate magnetic resonance imaging in the risk stratification, diagnosis and treatment pathway of men with prostate cancer is expanding. When quality prostate imaging is obtained, current evidence now supports its use in men at risk of harboring prostate cancer and who have not undergone a previous biopsy, as well as in men with an increasing prostate specific antigen following an initial negative standard prostate biopsy procedure.

Transrectal Ultrasound Guided Prostatic Biopsy and its Complications: A Descriptive Cross-sectional Study

INTRODUCTION

Transrectal ultrasound of prostate provides better visual for biopsy. Transrectal ultrasound guided prostate biopsy is usually performed in men with an abnormal digital rectal examination, and elevated prostate specific antigen (>4ng/ml) or prostate specific antigen velocity (rate of prostate specific antigen change) i.e., >0.4-0.75ng/ml/year. The aim of the study is to find out the complications of transrectal ultrasound guided prostatic biopsies.

METHODS

This descriptive cross-sectional study was done among 50 patients who transrectal ultrasound guided prostatic biopsies in a tertiary care hospital, from July 2017 to July 2019 after receiving ethical approval from the Institutional Review Committee of Kathmandu Medical College and teaching hospital. Convenient sampling was done. All patients were informed about the potential benefits and risks of the transrectal ultrasound guided prostate biopsy and patients signed an informed written consent form. Statistical analysis was done by using Statistical Package for Social Sciences version 16.

RESULTS

Mean prostate specific antigen was 34.571 and mean weight of prostate was 44.6gm. Moderate to severe pain was experienced by 15 (30%), 2 (4%) had hematuria with fever accounting for 3 (6%) patients. All were managed conservatively with no mortality related to the procedure and complication. Three patients was positive for malignancy on re-biopsy.

CONCLUSIONS

Transrectal ultrasound guided biopsy of prostate is a pioneer experience in Nepal. It has proved to be an useful tool of diagnosis of suspected carcinoma of Prostate. Use of neurovascular block may reduce the pain during the procedure.

Magnetic Resonance Imaging-targeted Biopsy Versus Systematic Biopsy in the Detection of Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Magnetic resonance imaging (MRI)-targeted prostate biopsy (MRI-TB) may be an alternative to systematic biopsy for diagnosing prostate cancer.

OBJECTIVE

The primary aims of this systematic review and meta-analysis were to compare the detection rates of clinically significant and clinically insignificant cancer by MRI-TB with those by systematic biopsy in men undergoing prostate biopsy to identify prostate cancer.

EVIDENCE ACQUISITION

A literature search was conducted using the PubMed, Embase, Web of Science, Cochrane library, and Clinicaltrials.gov databases. We included prospective and retrospective paired studies where the index test was MRI-TB and the comparator test was systematic biopsy. We also included randomised controlled trials (RCTs) if one arm included MRI-TB and another arm included systematic biopsy. The risk of bias was assessed using a modified Quality Assessment of Diagnostic Accuracy Studies-2 checklist. In addition, the Cochrane risk of bias 2.0 tool was used for RCTs.

EVIDENCE SYNTHESIS

We included 68 studies with a paired design and eight RCTs, comprising a total of 14709 men who either received both MRI-TB and systematic biopsy, or were randomised to receive one of the tests. MRI-TB detected more men with clinically significant cancer than systematic biopsy (detection ratio [DR] 1.16 [95% confidence interval {CI} 1.09-1.24], p<0.0001) and fewer men with clinically insignificant cancer than systematic biopsy (DR 0.66 [95% CI 0.57-0.76], p<0.0001). The proportion of cores positive for cancer was greater for MRI-TB than for systematic biopsy (relative risk 3.17 [95% CI 2.82-3.56], p<0.0001).

CONCLUSIONS

MRI-TB is an attractive alternative diagnostic strategy to systematic biopsy.

PATIENT SUMMARY

We evaluated the published literature, comparing two methods of diagnosing prostate cancer. We found that biopsies targeted to suspicious areas on magnetic resonance imaging were better at detecting prostate cancer that needs to be treated and avoiding the diagnosis of disease that does not need treatment than the traditional systematic biopsy.

Magnetic resonance imaging-guided targeted biopsy in risk classification among patients on active surveillance: A diagnostic meta-analysis

BACKGROUND

The aim of this study was to assess the sensitivity and accuracy of magnetic resonance imaging-guided targeted biopsy (MRI-TB) in patients undergoing active surveillance (AS) procedure.

METHODS

We searched databases to identify relevant studies which compared MRI-TB with systemic biopsy for diagnosing prostate cancer in patients on AS. Outcomes included sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the curve (AUC) and publication bias of AS group, confirmatory biopsy group and follow-up biopsy group.

RESULTS

Fourteen articles involving 1693 patients were included. In AS group, the sensitivity was 0.62 (95% confidence interval [CI], 0.57-0.68), specificity was 0.89 (95% CI, 0.87-0.90), NLR was 0.43 (0.31-0.60), PLR was 4.90 (3.50-6.86), DOR was 12.75 (7.22-22.51), and AUC was 0.8645. In confirmatory biopsy group, the sensitivity was 0.67 (0.59-0.74), specificity was 0.89 (0.86-0.91), NLR was 0.42 (0.27-0.65), PLR was 4.94 (3.88-6.30), DOR was 14.54 (9.60-22.02), and AUC was 0.8812. In follow-up biopsy group, the sensitivity was 0.35 (0.22-0.51), specificity was 0.88 (0.82-0.92), NLR was 0.76 (0.52-1.11), PLR was 3.06 (1.71-5.50), DOR was 4.41 (2.15-9.03), and AUC was 0.8367.

CONCLUSION

MRI-TB has a moderate-to-high diagnostic accuracy for diagnosing and reclassifying patients on AS with high specificity and AUC value under the SROC curve.

Comparison of cancer detection rates by transrectal prostate biopsy for prostate cancer using two different nomograms based on patient's age and prostate volume

Background

The aim of this study is to evaluate the efficacy of two different Nara Urological Research and Treatment Group (NURTG) nomograms allocating 6–12 biopsy cores based on age and prostate volume.

Materials and methods

From April 2006 to July 2014, a total of 1,605 patients who underwent initial prostate biopsy were enrolled. Based on a nomogram taking the patient’s age and prostate volume into consideration, 6–12 biopsy cores were allocated. Two types of nomogram were used, for the former group (before March 2009) and latter group (March 2009 onward). Cancer detection rates in all patients and those with prostate-specific antigen values in the gray zone (4.0–10 ng/mL) were compared. Predictive parameters for detection of prostate cancer in gray-zone patients were also investigated.

Results

The cancer detection rates in all patients and those in the gray zone were 48% and 38% in the former group and 54% and 41% in the latter group, respectively. The cancer detection rate in all patients was significantly higher in the latter group compared with the former group, but detection in gray-zone patients did not show a significant difference between the two groups (P=0.011 and P=0.37, respectively). Multivariate analysis indicated that age, digital rectal examination, prostate volume, transrectal ultrasonography findings, and volume/biopsy ratio were significant predictive parameters in gray-zone patients. The clinically insignificant cancer detection rate was significantly lower in the latter group compared with the former group (P=0.0008).

Conclusion

The latter nomogram provided more acceptable detection rates of clinically significant and insignificant cancer than the former one, and we consider that an initial maximum 12-core transrectal ultrasound-guided needle biopsy may be sufficient for prostate cancer diagnosis.

Predicting Gleason Group Progression for Men on Prostate Cancer Active Surveillance: Role of a Negative Confirmatory Magnetic Resonance Imaging-Ultrasound Fusion Biopsy

PURPOSE

Active surveillance has gained acceptance as an alternative to definitive therapy in many men with prostate cancer. Confirmatory biopsies to assess the appropriateness of active surveillance are routinely performed and negative biopsies are regarded as a favorable prognostic indicator. We sought to determine the prognostic implications of negative multiparametric magnetic resonance imaging-transrectal ultrasound guided fusion biopsy consisting of extended sextant, systematic biopsy plus multiparametric magnetic resonance imaging guided targeted biopsy of suspicious lesions on magnetic resonance imaging.

MATERIALS AND METHODS

All patients referred with Gleason Grade Group 1 or 2 prostate cancer based on systematic biopsy performed elsewhere underwent confirmatory fusion biopsy. Patients who continued on active surveillance after a positive or a negative fusion biopsy were followed. The baseline characteristics of the biopsy negative and positive cases were compared. Cox regression analysis was used to determine the prognostic significance of a negative fusion biopsy. Kaplan-Meier survival curves were used to estimate Grade Group progression with time.

RESULTS

Of the 542 patients referred with Grade Group 1 (466) or Grade Group 2 (76) cancer 111 (20.5%) had a negative fusion biopsy. A total of 60 vs 122 patients with a negative vs a positive fusion biopsy were followed on active surveillance with a median time to Grade Group progression of 74.3 and 44.6 months, respectively (p <0.01). Negative fusion biopsy was associated with a reduced risk of Grade Group progression (HR 0.41, 95% CI 0.22-0.77, p <0.01).

CONCLUSIONS

A negative confirmatory fusion biopsy confers a favorable prognosis for Grade Group progression. These results can be used when counseling patients about the risk of progression and for planning future followup and biopsies in patients on active surveillance.

Imaging as a Personalized Biomarker for Prostate Cancer Risk Stratification

Biomarkers provide objective data to guide clinicians in disease management. Prostate-specific antigen serves as a biomarker for screening of prostate cancer but has come under scrutiny for detection of clinically indolent disease. Multiple imaging techniques demonstrate promising results for diagnosing, staging, and determining definitive management of prostate cancer. One such modality, multiparametric magnetic resonance imaging (mpMRI), detects more clinically significant disease while missing lower volume and clinically insignificant disease. It also provides valuable information regarding tumor characteristics such as location and extraprostatic extension to guide surgical planning. Information from mpMRI may also help patients avoid unnecessary biopsies in the future. It can also be incorporated into targeted biopsies as well as following patients on active surveillance. Other novel techniques have also been developed to detect metastatic disease with advantages over traditional computer tomography and magnetic resonance imaging, which primarily rely on defined size criteria. These new techniques take advantage of underlying biological changes in prostate cancer tissue to identify metastatic disease. The purpose of this review is to present literature on imaging as a personalized biomarker for prostate cancer risk stratification.

Role of multiparametric magnetic resonance imaging for patients under active surveillance for prostate cancer: a systematic review with diagnostic meta-analysis

BACKGROUND

The use of multiparametric magnetic resonance imaging (mpMRI) in the setting of patients under active surveillance (AS) is promising. In this systematic-review we aimed to analyse the role of mpMRI in patients under AS.

METHODS

A comprehensive literature research for English-language original and review articles, recently published, was carried out using Medline, Scopus and Web of sciences databases until 30 October 2017. The following MeSH terms were used: 'active surveillance', 'prostate cancer', 'multiparametric magnetic resonance imaging'. A diagnostic meta-analysis was performed for 3.0 T mpMRI in predicting disease re-classification.

RESULTS

In total, 226 studies were selected after research and after removal of duplicates. After analysis on inclusion criteria, 43 studies were identified as eligible for this systematic review with a total of 6,605 patients. The timing of MRI during follow-up of AS differed from all studies like criteria for inclusion in the AS protocol. Overall, there was a low risk of bias across all studies. The diagnostic meta-analysis for 1.5 tesla showed a sensitivity of 0.60, negative predictive value (NPV) of 0.75 and a hierarchical summary receiving operating curve (HSROC) of 0.74 while for 3.0 tesla mpMRI a sensitivity of 0.81, a NPV of 0.78 and a HSROC of 0.83.

CONCLUSIONS

Overall, the available evidence suggests that both 1.5 or 3.0 Tesla mpMRI are a valid tool to monitor progression during AS follow-up, showing good accuracy capabilities in detecting PCa re-classification. However, the modality to better define what means 'disease progression' on mpMRI must be further evaluated.

MRI findings guiding selection of active surveillance for prostate cancer: a review of emerging evidence

Active surveillance (AS) for prostate cancer (PCa) is generally considered to be a safe strategy for men with low-risk, localized disease. However, as many as 1 in 4 patients may be incorrectly classified as AS-eligible using traditional inclusion criteria. The use of multiparametric magnetic resonance imaging (mpMRI) may offer improved risk stratification in both the initial diagnostic and disease monitoring setting. We performed a review of recently published studies to evaluate the utility of this imaging modality for this clinical setting. An English literature search was conducted on PubMed for original investigations on localized PCa, AS, and magnetic resonance imaging. Our Boolean criteria included the following terms: PCa, AS, imaging, MRI, mpMRI, prospective, retrospective, and comparative. Our search excluded publication types such as comments, editorials, guidelines, reviews, or interviews. Our literature review identified 71 original investigations. Among these, 52 met our inclusion criteria. Evidence suggests mpMRI improves characterization of clinically significant prostate cancer (csPCa) foci, and the enhanced detection and risk-stratification afforded by this modality may keep men from being inappropriately placed on AS. Use of serial mpMRI may also permit longer intervals between confirmatory biopsies. Multiple studies demonstrate the benefit of MRI-targeted biopsies. The use of mpMRI of the prostate offers improved confidence in risk-stratification for men with clinically low-risk PCa considering AS. While on AS, serial mpMRI and MRI-targeted biopsy aid in the detection of aggressive disease transformation or foci of clinically-significant cancer undetected on prior biopsy sessions.

Radiologist Quality Assurance by Nonradiologists at Tumor Board

PURPOSE

To explore the use of nonradiologists as a method to efficiently reduce bias in the assessment of radiologist performance using a hepatobiliary tumor board as a case study.

MATERIALS AND METHODS

Institutional review board approval was obtained for this HIPAA-compliant prospective quality assurance (QA) effort. Consecutive patients with CT or MR imaging reviewed at one hepatobiliary tumor board between February 2016 and October 2016 (n = 265) were included. All presentations were assigned prospective anonymous QA scores by an experienced nonradiologist hepatobiliary provider based on contemporaneous comparison of the imaging interpretation at a tumor board and the original interpretation(s): concordant, minor discordance, major discordance. Major discordance was defined as a discrepancy that may affect clinical management. Minor discordance was defined as a discrepancy unlikely to affect clinical management. All discordances and predicted management changes were retrospectively confirmed by the liver tumor program medical director. Logistic regression analyses were performed to determine what factors best predict discordant reporting.

RESULTS

Approximately one-third (30% [79 of 265]) of reports were assigned a discordance, including 51 (19%) minor and 28 (11%) major discordances. The most common related to mass size (41% [32 of 79]), tumor stage and extent (24% [19 of 79]), and assigned LI-RADS v2014 score (22% [17 of 79]). One radiologist had 11.8-fold greater odds of discordance (P = .002). Nine other radiologists were similar (P = .10-.99). Radiologists presenting their own studies had 4.5-fold less odds of discordance (P = .006).

CONCLUSIONS

QA conducted in line with tumor board workflow can enable efficient assessment of radiologist performance. Discordant interpretations are commonly (30%) reported by nonradiologist providers.

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.

Prostate Cancer Imaging and Biomarkers Guiding Safe Selection of Active Surveillance

Background

Active surveillance (AS) is a widely adopted strategy to monitor men with low-risk, localized prostate cancer (PCa). Current AS inclusion criteria may misclassify as many as one in four patients. The advent of multiparametric magnetic resonance imaging (mpMRI) and novel PCa biomarkers may offer improved risk stratification. We performed a review of recently published literature to characterize emerging evidence in support of these novel modalities.

Methods

An English literature search was conducted on PubMed for available original investigations on localized PCa, AS, imaging, and biomarkers published within the past 3 years. Our Boolean criteria included the following terms: PCa, AS, imaging, biomarker, genetic, genomic, prospective, retrospective, and comparative. The bibliographies and diagnostic modalities of the identified studies were used to expand our search.

Results

Our review identified 222 original studies. Our expanded search yielded 244 studies. Among these, 70 met our inclusion criteria. Evidence suggests mpMRI offers improved detection of clinically significant PCa, and MRI-fusion technology enhances the sensitivity of surveillance biopsies. Multiple studies demonstrate the promise of commercially available screening assays for prediction of AS failure, and several novel biomarkers show promise in this setting.

Conclusion

In the era of AS for men with low-risk PCa, improved strategies for proper stratification are needed. mpMRI has dramatically enhanced the detection of clinically significant PCa. The advent of novel biomarkers for prediction of aggressive disease and AS failure has shown some initial promise, but further validation is warranted.

What Are We Missing? False-Negative Cancers at Multiparametric MR Imaging of the Prostate

Purpose To characterize clinically important prostate cancers missed at multiparametric (MP) magnetic resonance (MR) imaging. Materials and Methods The local institutional review board approved this HIPAA-compliant retrospective single-center study, which included 100 consecutive patients who had undergone MP MR imaging and subsequent radical prostatectomy. A genitourinary pathologist blinded to MP MR findings outlined prostate cancers on whole-mount pathology slices. Two readers correlated mapped lesions with reports of prospectively read MP MR images. Readers were blinded to histopathology results during prospective reading. At histopathologic examination, 80 clinically unimportant lesions (<5 mm; Gleason score, 3+3) were excluded. The same two readers, who were not blinded to histopathologic findings, retrospectively reviewed cancers missed at MP MR imaging and assigned a Prostate Imaging Reporting and Data System (PI-RADS) version 2 score to better understand false-negative lesion characteristics. Descriptive statistics were used to define patient characteristics, including age, prostate-specific antigen (PSA) level, PSA density, race, digital rectal examination results, and biopsy results before MR imaging. Student t test was used to determine any demographic differences between patients with false-negative MP MR imaging findings and those with correct prospective identification of all lesions. Results Of the 162 lesions, 136 (84%) were correctly identified with MP MR imaging. Size of eight lesions was underestimated. Among the 26 (16%) lesions missed at MP MR imaging, Gleason score was 3+4 in 17 (65%), 4+3 in one (4%), 4+4 in seven (27%), and 4+5 in one (4%). Retrospective PI-RADS version 2 scores were assigned (PI-RADS 1, n = 8; PI-RADS 2, n = 7; PI-RADS 3, n = 6; and PI-RADS 4, n = 5). On a per-patient basis, MP MR imaging depicted clinically important prostate cancer in 99 of 100 patients. At least one clinically important tumor was missed in 26 (26%) patients, and lesion size was underestimated in eight (8%). Conclusion Clinically important lesions can be missed or their size can be underestimated at MP MR imaging. Of missed lesions, 58% were not seen or were characterized as benign findings at second-look analysis. Recognition of the limitations of MP MR imaging is important, and new approaches to reduce this false-negative rate are needed. ^© RSNA, 2017 Online supplemental material is available for this article.

Clinically insignificant prostate cancer suitable for active surveillance according to Prostate Cancer Research International: Active surveillance criteria: Utility of PI-RADS v2

BACKGROUND

Active surveillance (AS) is an important treatment strategy for prostate cancer (PCa). Prostate Imaging-Reporting and Data System (PI-RADS) v2 has been addressed, but few studies have reported the value of PI-RADS v2 for assessing risk stratification in patients with PCa, especially on selecting potential candidates for AS.

PURPOSE

To investigate the utility of PI-RADS v2 and apparent diffusion coefficient (ADC) in evaluating patients with insignificant PCa, who are suitable for AS.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 238 patients with PCa who met the Prostate Cancer Research International: Active Surveillance criteria underwent radical prostatectomy.

FIELD STRENGTH/SEQUENCE

3.0T, including T₂ -weighted, diffusion-weighted, and dynamic contrast-enhanced imaging.

ASSESSMENT

Insignificant cancer was defined histopathologically as an organ-confined disease with a tumor volume <0.5 cm³ without Gleason score 4-5. Patients were divided into two groups based on the PI-RADS v2 and tumor ADC: A, PI-RADS score ≤3 and ADC ≥1.095 × 10^-3 mm² /s; and B, PI-RADS score 4-5 or ADC <1.095 × 10^-3 mm² /s. Preoperative clinical and imaging variables were evaluated regarding the associations with insignificant cancer.

RESULTS

Of the 238 patients, 101 (42.8%) were diagnosed with insignificant cancer on pathological findings. The number of positive cores, prostate-specific antigen density (PSAD), PI-RADS v2 and tumor ADC were significantly associated with insignificant cancer on univariate analysis (P < 0.05). However, multivariate analysis indicated tumor ADC (odds ratio [OR] = 4.57, P < 0.001) and PI-RADS v2 (OR = 3.60, P < 0.001) were independent predictors of insignificant cancer. Area under the receiver operating characteristics curve (AUC) reached 0.803 when PI-RADS v2 (AUC = 0.747) was combined with tumor ADC (AUC = 0.786).

DATA CONCLUSION

The PI-RADS v2 together with tumor ADC may be a useful marker for predicting patients with insignificant PCa when considering AS.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1072-1079.

Co-registration of MRI and ultrasound: accuracy of targeting based on radiology-pathology correlation

We reviewed the role of multiparametric magnetic resonance imaging (MP-MRI) and methods of MRI guided biopsy including in-bore, cognitive fusion, and software-based fusion. MP-MRI has been developed, optimized, and studied as a means of improving prostate cancer detection beyond the standard evaluation that utilizes digital rectal examinations and serum prostate specific antigen (PSA). MP-MRI has been proven to be an excellent diagnostic imaging modality that improves prostate cancer detection and risk stratification by guiding biopsy samples. The co-registration between MRI and ultrasound has allowed for software-based fusion which enables office-based biopsy procedures while still benefiting from the detailed prostate characterization of MRI. MP-MRI/ultrasound fusion guided biopsy has been studied in detail as this technology has been developed, tested, and validated in the past decade. The imaging to pathology correlation supporting the use of MP-MRI/ultrasound fusion is well documented in the literature. As the indication for the use of prostate MP-MRI becomes more widespread, it is important to continue to evaluate the correlation between imaging and pathologic findings.

Prostatic intraepithelial neoplasia-like ductal prostatic adenocarcinoma: A case suitable for active surveillance?

In contrast to typical prostatic ductal adenocarcinoma, prostatic intraepithelial neoplasia (PIN)-like ductal adenocarcinoma is a rare variant of prostate cancer with low-grade clinical behavior. We report a case of a 66-year-old African-American male with an elevated serum prostate-specific antigen who underwent multiparametric prostate magnetic resonance imaging (MRI) and MRI/ultrasound fusion-guided biopsies. Pathology demonstrated low-volume Gleason score 3 + 3 = 6 (Grade Group 1), acinar adenocarcinoma involving one core and PIN-like ductal adenocarcinoma on a separate core. Herein, we discuss the potential role of active surveillance for patients with this rare variant of prostate cancer found in the era of advanced imaging with multiparametric MRI for prostate cancer.

Integration of multiparametric MRI into active surveillance of prostate cancer

Prostate cancer is the most common noncutaneous cancer in men though many men will not die of this disease and may not require definitive treatment. Active surveillance (AS) is an increasingly utilized potential solution to the issue of overtreatment of prostate cancer. Traditionally, prostate cancer patients have been stratified into risk groups based on clinical stage on digital rectal examination, prostate-specific antigen and biopsy Gleason score, though each of these variables has significant limitations. This review will discuss the potential role for prostate multiparametric MRI and targeted biopsy techniques incorporating MRI in the selection of candidates for AS, monitoring patients on AS and as triggers for definitive treatment.

Geometric systematic prostate biopsy

OBJECTIVE

The common sextant prostate biopsy schema lacks a three-dimensional (3D) geometric definition. The study objective was to determine the influence of the geometric distribution of the cores on the detection probability of prostate cancer (PCa).

METHODS

The detection probability of significant (>0.5 cm³) and insignificant (<0.2 cm³) tumors was quantified based on a novel 3D capsule model of the biopsy sample. The geometric distribution of the cores was optimized to maximize the probability of detecting significant cancer for various prostate sizes (20-100cm³), number of biopsy cores (6-40 cores) and biopsy core lengths (14-40 mm) for transrectal and transperineal biopsies.

RESULTS

The detection of significant cancer can be improved by geometric optimization. With the current sextant biopsy, up to 20% of tumors may be missed at biopsy in a 20 cm³ prostate due to the schema. Higher number and longer biopsy cores are required to sample with an equal detection probability in larger prostates. Higher number of cores increases both significant and insignificant tumor detection probability, but predominantly increases the detection of insignificant tumors.

CONCLUSION

The study demonstrates mathematically that the geometric biopsy schema plays an important clinical role, and that increasing the number of biopsy cores is not necessarily helpful.

Magnetic Resonance Imaging-Ultrasound Fusion-Guided Prostate Biopsy: Review of Technology, Techniques, and Outcomes

Transrectal ultrasound (TRUS)-guided (12-14 core) systematic biopsy of the prostate is the recommended standard for patients with suspicion of prostate cancer (PCa). Advances in imaging have led to the application of magnetic resonance imaging (MRI) for the detection of PCa with subsequent development of software-based co-registration allowing for the integration of MRI with real-time TRUS during prostate biopsy. A number of fusion-guided methods and platforms are now commercially available with common elements in image and analysis and planning. Implementation of fusion-guided prostate biopsy has now been proven to improve the detection of clinically significant PCa in appropriately selected patients.

Magnetic Resonance Imaging-Transrectal Ultrasound Guided Fusion Biopsy to Detect Progression in Patients with Existing Lesions on Active Surveillance for Low and Intermediate Risk Prostate Cancer

PURPOSE

Active surveillance is an established option for men with low risk prostate cancer. Multiparametric magnetic resonance imaging with magnetic resonance imaging-transrectal ultrasound fusion guided biopsy may better identify patients for active surveillance compared to systematic 12-core biopsy due to improved risk stratification. To our knowledge the performance of multiparametric magnetic resonance imaging in following men on active surveillance with visible lesions is unknown. We evaluated multiparametric magnetic resonance imaging and magnetic resonance imaging-transrectal ultrasound fusion guided biopsy to monitor men on active surveillance.

MATERIALS AND METHODS

This retrospective review included men from 2007 to 2015 with prostate cancer on active surveillance in whom magnetic resonance imaging visible lesions were monitored by multiparametric magnetic resonance imaging and fusion guided biopsy. Progression was defined by ISUP (International Society of Urological Pathology) grade group 1 to 2 and ISUP grade group 2 to 3. Significance was considered at p ≤0.05.

RESULTS

A total of 166 patients on active surveillance with 2 or more fusion guided biopsies were included in analysis. Mean followup was 25.5 months. Of the patients 29.5% had pathological progression. Targeted biopsy alone identified 44.9% of patients who progressed compared to 30.6% identified by systematic 12-core biopsy alone (p = 0.03). Fusion guided biopsy detected 26% more cases of pathological progression on surveillance biopsy compared to systematic 12-core biopsy. Progression on multiparametric magnetic resonance imaging was the sole predictor of pathological progression at surveillance biopsy (p = 0.013). Multiparametric magnetic resonance imaging progression in the entire cohort had 81% negative predictive value, 35% positive predictive value, 77.6% sensitivity and 40.5% specificity in detecting pathological progression.

CONCLUSIONS

Multiparametric magnetic resonance imaging progression predicts the risk of pathological progression. Patients with stable multiparametric magnetic resonance imaging findings have a low rate of progression. Incorporating fusion guided biopsy in active surveillance nearly doubled our detection of pathological progression compared to systematic 12-core biopsy.

Diagnosis and Monitoring of Prostatic Lesions: A Comparison of Three Modalities: Multiparametric MRI, Fusion MRI/Transrectal Ultrasound (TRUS), and Traditional TRUS

PURPOSE

 Transrectal ultrasound (TRUS) has been the gold standard of imaging for diagnosing prostate cancer for decades but is plagued by user error and undersampling. We aim to explore imaging modalities that are now being used in combination or alone for screening, diagnosis, and/or active surveillance of prostate cancer.

METHODS

A PubMed literature search was performed to include articles published up to April 2016. Data were extracted and analyzed.

RESULTS

Several large-scale studies have found an increased cancer detection rate in MRI-targeted lesions with an improved ability to target anterior lesions as well as an increased cancer detection in high-risk cancers using fusion platforms vs TRUS alone.

CONCLUSIONS

To date, there have been few head-to-head trials to directly compare the use of multiparametric MRI (mpMRI), transrectal ultrasound, and MRI-ultrasound fusion modalities for accurate and reliable detection, active surveillance, or biopsy procedure success rates. Further investigation utilizing these modalities are needed before they can be relied upon in active surveillance management, although mpMRI appears to be currently the most reliable in monitoring and diagnosing prostate lesions.

Risk stratification of prostate cancer: integrating multiparametric MRI, nomograms and biomarkers

Accurate risk stratification of prostate cancer is achieved with a number of existing tools to ensure the identification of at-risk patients, characterization of disease aggressiveness, prediction of cancer burden and extrapolation of treatment outcomes for appropriate management of the disease. Statistical tables and nomograms using classic clinicopathological variables have long been the standard of care. However, the introduction of multiparametric MRI, along with fusion-guided targeted prostate biopsy and novel biomarkers, are being assimilated into clinical practice. The majority of studies to date present the outcomes of each in isolation. The current review offers a critical and objective assessment regarding the integration of multiparametric MRI and fusion-guided prostate biopsy with novel biomarkers and predictive nomograms in contemporary clinical practice.

Midline lesions of the prostate: role of MRI/TRUS fusion biopsy and implications in Gleason risk stratification

PURPOSE

MRI-TRUS fusion biopsy (FBx) has proven efficacy in targeting suspicious areas that are traditionally missed by systematic 12-core biopsy (SBx). Midline prostate lesions are undersampled during SBx, as traditional approaches aim laterally during TRUS biopsy. The aim of our study was to determine the utility of FBx for targeting midline lesions identified on multiparametric MRI (mpMRI).

METHODS

A review was performed of a prospectively maintained database of patients undergoing mpMRI followed by FBx and SBx from 2007 to 2015. Midline location was defined as any lesion crossing the midline on axial imaging and involving both prostatic lobes. Index lesion was defined as lesion with highest Gleason score on biopsy. Patient demographic, imaging, and histopathologic data were collected. Multivariate logistic regression was conducted to determine independent predictors of having clinically significant (CS) cancer (Gleason ≥ 7) in midline lesions.

RESULTS

Out of 1266 patients, we identified 202 suspicious midline lesions in 190 patients [median (IQR) age 63 (10) years; PSA 7.6 (6.6)]. Eighty-eight (46.3 %) patients had cancer detection on FBx of midline lesion. A midline target represented the index lesion of the prostate in 63/190 (33.2 %) patients. Risk category upgrading based on FBx of a midline lesion compared to SBx occurred in 45/190 patients (23.7 %). On multivariate analysis, higher PSA (p = .001), lower MRI-derived prostate volume (p < .001), and moderate-high or high suspicion on mpMRI (p = .014) predicted CS cancer in midline lesions.

CONCLUSIONS

MRI-TRUS FBx facilitates sampling of midline lesions. Integration of mpMRI and FBx for targeting of midline lesions improves detection of CS prostate cancer.

A urologist's perspective on prostate cancer imaging: past, present, and future

Prostate cancer is unique in that unlike other solid organ malignancies, only recently has imaging been employed to routinely detect and localize disease. The introduction of transrectal ultrasound was a significant development, transitioning digitally guided prostate biopsies to ultrasound guidance. The arrival of multiparametric MRI has become the next major step, transforming the way Urologist's diagnose, stage, and treat prostate cancer. Recent recommendations against PSA screening have changed the landscape of urologic oncology with the changing needs being reflected in the initiation of additional robust imaging techniques at different time points in prostate cancer care. The current review aims to provide a clinical perspective in the history, current standard of care, and novel imaging modalities in the evaluation of prostate cancer.

Optimizing Patient Population for MP-MRI and Fusion Biopsy for Prostate Cancer Detection

The diagnosis and treatment of prostate cancer continue to evolve with advances in science and technology. The utilization of multiparametric MRI (mp-MRI) to identify lesions in the prostate has given clinicians the ability to visualize malignancy in the prostate with greater confidence. With this new ability came the advancement of fusion biopsy platforms, which allow for direct targeting of these lesions. As with any new technology in medicine, the proper use of these modalities and how they fit into current clinical practice need to be addressed. This review summarizes the current knowledge on how to best optimize which men undergo mp-MRI and fusion biopsies both in the screening and treatment settings.

Prostate Cancer Diagnosis on Repeat Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy of Benign Lesions: Recommendations for Repeat Sampling

PURPOSE

Urologists face a dilemma when a lesion identified on multiparametric magnetic resonance imaging is benign on image guided fusion biopsy. We investigated the detection rate of prostate cancer on repeat fusion biopsy in multiparametric magnetic resonance imaging lesions initially found to be pathologically benign on fusion biopsy.

MATERIALS AND METHODS

We reviewed the records of all patients from 2007 to 2014 who underwent multiparametric magnetic resonance imaging and image guided fusion biopsy. We identified men who underwent rebiopsy of the same discrete lesion after initial fusion biopsy results were benign. Data were documented on a per lesion basis. We manually reviewed UroNav system (Invivo, Gainesville, Florida) needle tracking to verify accurate image registration. Multivariate analysis was used to identify clinical and imaging factors predictive of prostate cancer detection at repeat fusion biopsy.

RESULTS

A total of 131 unique lesions were rebiopsied in 90 patients. Of these 131 resampled lesions 21 (16%) showed prostate cancer, which in 13 (61.9%) was Gleason 3 + 3. On multivariate analysis only lesion growth on repeat multiparametric magnetic resonance imaging was significantly associated with prostate cancer detection at repeat biopsy (HR 3.274, 95% CI 1.205-8.896, p = 0.02).

CONCLUSIONS

Pathologically benign multiparametric magnetic resonance imaging lesions on initial image guided fusion biopsy are rarely found to harbor clinically significant prostate cancer on repeat biopsy. When prostate cancer was identified, most disease was low risk. An increase in lesion diameter was an independent predictor of prostate cancer detection. While these data are retrospective, they may provide some confidence in the reliability of negative initial image guided fusion biopsies despite a positive multiparametric magnetic resonance imaging finding.

The characteristics and spatial distributions of initially missed and rebiopsy-detected prostate cancers

Purpose:

The purpose of this study was to analyze the characteristics of initially missed and rebiopsy-detected prostate cancers following 12-core transrectal biopsy.

Methods:

A total of 45 patients with prostate cancers detected on rebiopsy and 45 patients with prostate cancers initially detected on transrectal ultrasound-guided biopsy were included in the study. For result analysis, the prostate was divided into six compartments, and the cancer positive rates, estimated tumor burden, and agreement rates between biopsy and surgical specimens, along with clinical data, were evaluated.

Results:

The largest mean tumor burden was located in the medial apex in both groups. There were significantly more tumors in this location in the rebiopsy group (44.9%) than in the control group (30.1%, P=0.015). The overall sensitivity of biopsy was significantly lower in the rebiopsy group (22.5% vs. 43.4%, P<0.001). The agreement rate of cancer positive cores between biopsy and surgical specimens was significantly lower in the medial apex in the rebiopsy group compared with that of the control group (50.0% vs. 65.6%, P=0.035). The cancer positive rates of target biopsy cores and premalignant lesions in the rebiopsy group were 63.1% and 42.3%, respectively.

Conclusion:

Rebiopsy-detected prostate cancers showed different spatial distribution and lower cancer detection rate of biopsy cores compared with initially diagnosed cancers. To overcome lower cancer detection rate, target biopsy of abnormal sonographic findings, premalignant lesions and medial apex which revealed larger tumor burden would be recommended when performing rebiopsy.

Active surveillance and focal therapy for low-intermediate risk prostate cancer

Low risk and many cases of low-intermediate risk prostate cancer, are indolent, have little or no metastatic potential, and are not life threatening. Major advances have been made in understanding who these patients are, and in encouraging the use of conservative management in such individuals. Conservative management incorporates the early identification of those 'low risk' patients who harbor higher risk disease, and benefit from definitive therapy. Based on the current algorithm of PSA followed by systematic biopsy, this represents about 30% of newly diagnosed low risk patients. A further small proportion of patients with low risk disease demonstrate biological progression to higher grade disease. Men with lower risk disease can defer treatment, usually for life. Men with higher risk disease that can be localized to a relatively small volume of the prostate may be candidates for focal, prostate sparing therapy. The results of active surveillance, embodying conservative management with selective delayed intervention for the subset who are re-classified as higher risk over time based on repeat biopsy, imaging, or biomarker results, have shown that this approach is safe in the intermediate to long term, with a 1-5% cancer specific mortality at 15 years. Further refinement of the surveillance approach is ongoing, incorporating MRI, targeted biopsies, and molecular biomarkers.