Retrospective comparison of direct in-bore magnetic resonance imaging (MRI)-guided biopsy and fusion-guided biopsy in patients with MRI lesions which are likely or highly likely to be clinically significant prostate cancer

Targeted biopsy of the prostate

Diagnostic multiparametric MRI of the prostate has steadily evolved over the last three decades and can now reliably depict the dominant tumor in most men with prostate cancer. In response, several methods of targeted biopsy to direct tissue sampling of suspected tumor foci seen at multiparametric MRI have been developed and successfully tested in recent years, including software-assisted MRI-ultrasound (US) fusion biopsy and direct MRI-guided in-bore biopsy. These advances are leading to a sea change in the approach to prostate cancer diagnosis, with the traditional approach of blind systematic biopsy increasingly being replaced by MRI directed targeted biopsy. This review aims to describe the current status of targeted biopsy, with an emphasis on the relative accuracy of different techniques. The results of several critical large multicenter trials are presented, while unanswered questions that require more research are highlighted.

MRI-Ultrasound Fused Approach for Prostate Biopsy-How It Is Performed

The use of MRI-ultrasound image fusion targeted biopsy of the prostate in the face of an elevated serum PSA is now recommended by multiple societies, and results in improved detection of clinically significant cancer and, potentially, decreased detection of indolent disease. This combines the excellent sensitivity of MRI for clinically significant prostate cancer and the real-time biopsy guidance and confirmation of ultrasound. Both transperineal and transrectal approaches can be implemented using cognitive fusion, mechanical fusion with an articulated arm and electromagnetic registration, or pure software registration. The performance has been shown comparable to in-bore MRI biopsy performance. However, a number of factors influence the performance of this technique, including the quality and interpretation of the MRI, the approach used for biopsy, and experience of the practitioner, with most studies showing comparable performance of MRI-ultrasound fusion to in-bore targeted biopsy. Future improvements including artificial intelligence promise to refine the performance of all approaches.

Prostate cancer detection and complications of MRI-targeted prostate biopsy using cognitive registration, software-assisted image fusion or in-bore guidance: a systematic review and meta-analysis of comparative studies

BACKGROUND

Three primary strategies for MRI-targeted biopsies (TB) are available: Cognitive TB (COG-TB), MRI-US Fusion TB (FUS-TB), and In Bore TB (IB-TB). Despite nearly a decade of practice, a consensus on the preferred approach is lacking, with previous studies showing comparable PCa detection rates among the three methods.

METHODS

We conducted a search of PubMed, EMBASE, PubMed, Web of Science, and Scopus databases from 2014 to 2023, to identify studies comparing at least two of the three methods and reporting clinically significant PCa (csPCa) detection rates. The primary and secondary outcomes were to compare the csPCa and insignificant prostate cancer (iPCa, ISUP GG 1) detection rates between TB techniques. The tertiary outcome was to compare the complication rate between TB techniques. Detection rates were pooled using random-effect models. Planned sensitivity analyses included subgroup analysis according to the definition of csPCa and positive MRI, previous biopsy status, biopsy route, prostate volume, and lesion characteristics.

RESULTS

A total of twenty studies, involving 4928 patients, were included in the quantitative synthesis. The meta-analysis unveiled comparable csPCa detection rates among COG-TB (0.37), FUS-TB (0.39), and IB-TB (0.47). iPCa detection rate was also similar between TB techniques (COG-TB: 0.12, FUS-TB: 0.17, IB-TB: 0.18). All preplanned sensitivity analyses were conducted and did not show any statistically significant difference in the detection of csPCa between TB methods. Complication rates, however, were infrequently reported, and when available, no statistically significant differences were observed among the techniques.

CONCLUSIONS

This unique study, exclusively focusing on comparative research, indicates no significant differences in csPCa and iPCa detection rates between COG-TB, FUS-TB, and IB-TB. Decisions between these techniques may extend beyond diagnostic accuracy, considering factors such as resource availability and operator preferences. Well-designed prospective studies are warranted to refine our understanding of the optimal approach for TB in diverse clinical scenarios.

Direct MRI-guided In-Bore Targeted Biopsy of the Prostate: A Step-by-Step How To and Lessons Learned

Multiparametric MRI-the most accurate imaging technique for detection of prostate cancer-has transformed the landscape of prostate cancer diagnosis by enabling targeted biopsies. In a targeted biopsy, tissue samples are obtained from suspicious regions identified at prebiopsy diagnostic MRI. The authors briefly compare the different strategies available for targeting an MRI-visible suspicious lesion, followed by a step-by-step description of the direct MRI-guided in-bore approach and an illustrated review of its application in challenging clinical scenarios. In this technique, direct visualization of the needle, needle guide, and needle trajectory during the procedure provides a precise and versatile strategy to accurately sample suspicious lesions, improving detection of clinically significant cancers. Published under a CC BY 4.0 license Test Your Knowledge questions for this article are available in the supplemental material.

Targeted Prostate Biopsies-What the Radiologist Needs to Know

The emergence of multiparametric MR imaging has enabled a more reliable targeted approach to diagnosis of prostate cancer. Targeted biopsies are central to the MR imaging-dependent pathway to prostate cancer diagnosis and potentially improve the detection of clinically significant prostate cancers. In a targeted biopsy, tissue samples are obtained from suspicious regions identified on a prebiopsy diagnostic MR imaging. This article describes and compares principles, advantages, and disadvantages of the different strategies available for targeting an MR imaging-visible suspicious lesion.

Prostate MRI and PSMA-PET in the Primary Diagnosis of Prostate Cancer

Over the last years, prostate magnetic resonance imaging (MRI) has gained a key role in the primary diagnosis of clinically significant prostate cancer (csPCa). While a negative MRI can avoid unnecessary prostate biopsies and the overdiagnosis of indolent cancers, a positive examination triggers biopsy samples targeted to suspicious imaging findings, thus increasing the diagnosis of csPCa with a sensitivity and negative predictive value of around 90%. The limitations of MRI, including suboptimal positive predictive values, are fueling debate on how to stratify biopsy decisions and management based on patient risk and how to correctly estimate it with clinical and/or imaging findings. In this setting, "next-generation imaging" imaging based on radiolabeled Prostate-Specific Membrane Antigen (PSMA)-Positron Emission Tomography (PET) is expanding its indications both in the setting of primary staging (intermediate-to-high risk patients) and primary diagnosis (e.g., increasing the sensitivity of MRI or acting as a problem-solving tool for indeterminate MRI cases). This review summarizes the current main evidence on the role of prostate MRI and PSMA-PET as tools for the primary diagnosis of csPCa, and the different possible interaction pathways in this setting.

Comparative Effectiveness of Magnetic Resonance Imaging-Ultrasound Fusion Versus In-bore Magnetic Resonance Imaging-targeted Prostate Biopsy

OBJECTIVE

To examine the comparative effectiveness of magnetic resonance imaging-ultrasound (MRI-U/S) fusion biopsy and in-bore MRI-targeted biopsy.

METHODS

We identified men aged 18-89 with a diagnosis of elevated prostate specific antigen (PSA) or Gleason 6 prostate cancer on active surveillance who underwent MRI-U/S fusion prostate biopsy (12-core + targeted) in the office or in-bore MRI-targeted biopsy (MRI-IB; targeted only). The cancer detection rate (CDR; Gleason 6-10) and clinically significant CDR (csCDR; Gleason 7-10) were compared across biopsy techniques, adjusted for patient and radiographic features.

RESULTS

A total of 280 patients (346 lesions) were included, of whom 23.9% were on active surveillance for Gleason 6 prostate cancer. In the per-patient analyses, there was no statistically significant difference in adjusted overall CDR (64.1% vs 54.2%; P = .24) or csCDR (36.5% vs 37.9%; P = .85) between MRI-U/S and MRI-IB biopsy. In the per-lesion analyses, there was no statistically significant difference in adjusted overall CDR (45.7% vs 50.1%; P = .49) between MRI-U/S and MRI-IB biopsy, but MRI-IB biopsy was associated with a higher csCDR than MRI-U/S biopsy (32.8% vs 21.4%; P = .02).

CONCLUSION

We observed no statistically significant differences in cancer detection rates between MRI-U/S fusion biopsy and MRI-IB biopsy in per-patient analyses. However, MRI-IB biopsy was associated with higher csCDR when considering targeted biopsy cores only. These results suggest that systematic cores should be obtained when performing MRI-U/S fusion biopsy.

Selecting patients for magnetic resonance imaging cognitive versus ultrasound fusion biopsy of the prostate: A within‐patient comparison

Objectives

To compare overall agreement between magnetic resonance imaging (MRI)–ultrasound (US) fusion biopsy (FB) and MRI cognitive fusion biopsy (CB) of the prostate and determine which factors affect agreement for prostate cancer (PCa) who underwent both modalities in a prospective within‐patient protocol.

Patients and Methods

From August 2017 to January 2021, patients with at least one Prostate Imaging Reporting & Data System (PI‐RADS) 3 or higher lesion on multiparametric MRI underwent transrectal FB and CB in a prospective within‐patient protocol. CB was performed for each region of interest (ROI), followed by FB, followed by standard 12 core biopsy. Patients who were not on active surveillance were analysed. The primary endpoint was agreement for any PCa detection. McNemar's test and kappa statistic were used to analyse agreement. Chi‐square test, Fisher's exact test and Wilcoxon rank sum test were used to analyse disagreement across clinical and MRI spatial variables. A multivariable generalized mixed‐effect model was used to compare the interaction between select variables and fusion modality. Statistics were performed using SAS and R.

Results

Ninety patients and 98 lesions were included in the analysis. There was moderate agreement between FB and CB (k = 0.715). McNemar's test was insignificant (p = 0.285). Anterior location was the only variable associated with a significant variation in agreement, which was 70% for anterior lesions versus 89.7% for non‐anterior lesions (p = 0.035). Discordance did not vary significantly across other variables. In a mixed‐effect model, the interaction between anterior location and use of FB was insignificant (p = 0.411).

Conclusion

In a within‐patient protocol of patients not on active surveillance, FB and CB performed similarly for PCa detection and with moderate agreement. Anterior location was associated with significantly higher disagreement, whereas other patient and lesion characteristics were not. Additional studies are needed to determine optimal biopsy technique for sampling anterior ROI.

Fusion versus cognitive MRI-guided prostate biopsies in diagnosing clinically significant prostate cancer

Objective:

This study assesses whether fusion or cognitive magnetic resonance imaging (MRI)-guided prostate targeted and systematic transperineal biopsies (TPB) increase detection of clinically significant prostate cancer (csPCa).

Materials and Methods:

A retrospective analysis was completed of patients (2018–2020) undergoing 3-Tesla multiparametric prostate MRI informing targeted (either cognitive or MIM software fusion approach) and systematic TPB. ISUP (International Society of Urological Pathology) grade group ⩾ 2 was considered csPCa.

Results:

A total of 355 cases from 4 urologists were included; 131 were fusion and 224 were cognitive MRI-guided biopsies. Of all csPCa found, 86.8% ( n = 171) of cases were confirmed to be at the MRI-indicated location and 11.6% were found as part of active surveillance. In all, 45.0% of the fusion group were found to have csPCa, compared to 62.05% ( n = 139) in the cognitive group ( p = 0.002). csPCa detection rates varied between urologists (41% to 78%, p < 0.001), so a subgroup analysis was performed on Urologist A; 45.0% of fusion and 41.3% of cognitive biopsies had csPCa ( p = 0.644). Multinomial logistic regression analysis showed that biopsy type, being on active surveillance, number of biopsy cores, iPSA (initial Prostate Specific Antigen) value or PIRADS (Prostate Imaging-Reporting and Data System) score made no significant difference in whether csPCa was found.

Conclusion:

Cognitive and fusion targeting had similar csPCa detection rates. Further prospective studies would be beneficial to validate these findings.

Level of evidence:

2b (according to Oxford Centre for Evidence-Based Medicine)

Transrectal ultrasound features and biopsy outcomes of transition PI-RADS 5

BACKGROUND

Transition Prostate Imaging and Reporting and Data System (PI-RADS) 5 is easily detected owing to typical magnetic resonance imaging features. However, it is unclear as to how transition PI-RADS 5 appears on transrectal ultrasound (TRUS).

PURPOSE

To assess TRUS features of transition PI-RADS 5 and outcomes of TRUS-guided target biopsy.

MATERIAL AND METHODS

Between March 2014 and November 2018, 186 male patients underwent TRUS-guided biopsy of PI-RADS 5. Of them, 82 and 104were transition and peripheral PI-RADS 5, respectively. Transition and peripheral PI-RADS 5 were compared according to echogenicity (hyperechoic or hypoechoic) and hypoechoic rim (present or absent). Each tumor was targeted with TRUS based on TRUS features. Significant (Gleason score ≥7) and insignificant (Gleason score 6) cancer detection rates (CDRs) were compared between transition and peripheral PI-RADS 5. Standard reference was biopsy examination. Fisher's exact test was used for statistical analysis.

RESULTS

Transition PI-RADS 5 was hyperechoic in 89.0% (73/82) and had a hypoechoic rim in 97.6% (80/82), whereas peripheral PI-RADS 5 was hypoechoic in 99.0% (103/104) and had a hypoechoic rim in 26.9% (28/104) (both, P<0.0001). The significant CDRs of transition and peripheral PI-RADS 5 were 56.1% (46/82) and 65.4% (68/104), respectively (P=0.2263). However, the insignificant CDRs of these categories were 22.0% (18/82) and 8.7% (9/104), respectively (P=0.0123).

CONCLUSION

Transition PI-RADS 5 tends to have hyperechoic echogenicity and a hypoechoic rim. These findings help to target the transition PI-RADS 5 using TRUS. However, transition PI-RADS 5 is confirmed more frequently as insignificant cancer than peripheral PI-RADS 5.

Image-Guided Targeted Prostate Biopsies

Prostate cancer is the second most common cancer in the United States. Screening for prostate cancer has increased through the usage of prostate specific antigen and biopsies. Traditionally, prostate biopsies are done using transrectal ultrasound with 10-12 cores obtained in a sextant pattern. Advances in prostate imaging with multiparametric magnetic resonance imaging has led to image guided targeted prostate biopsies. This can be done with cognitive fusion, MRI-fusion, and in-bore MRI. This article will review the indications, techniques, and outcomes for targeted image guided prostate biopsies using in-bore MRI and MRI fusion.

MRI-directed biopsy for primary detection of prostate cancer in a population of 223 men: MRI In-Bore vs MRI-transrectal ultrasound fusion-targeted techniques

Objectives:

To compare the detection rates of overall prostate cancer (PCa) and clinically significant PCa (csPCa) and the median percentage of cancer per biopsy core between MRI-guided In-bore and MRI-TRUS fusion-targeted biopsy (TBx).

Methods:

In this retrospective study, 223 patients who underwent prostate multiparametric MRI (mpMRI) and subsequent MR-directed biopsy were included. For PCa and csPCa detection rate (DR), contingency tables were tested via the Pearson’s chi-squared to explore the variance of the outcome distribution. The percentage of cancer per biopsy core was tested with a two-tailed Mann-Withney test.

Results:

One hundred and seventeen and 106 patients underwent MRI-TRUS fusion or MRI In-bore TBx, respectively. 402 MRI biopsy targets were identified, of which 206 (51.2%) were biopsied with the MRI-TRUS TBx and 196 (48.8%) with the MRI In-bore TBx technique. Per-patient PCa and csPCa detection rates were 140/223 (62.8%) and 97/223 (43.5%), respectively. PCa-DR was 73/117 (62.4%) and 67/106 (63.2%) for MRI-TRUS and MRI In-Bore TBx (p = 0.9), while csPCa detection rate reached 50/117 (42.7%) and 47/106 (44.3%), respectively (p = 0.81). The median per-patient percentage of malignant tissue within biopsy cores was 50% (IQR: 27–65%) for PCa and 60% (IQR: 35–68%) for csPCa, with a statistically significant difference between the techniques.

Conclusion

No statistically significant difference in the detection rate of MRI In-bore and MRI-TRUS fusion TBx was found. MRI In-bore TBx showed higher per-core percentage of malignant cells.

Advances in knowledge

MRI In-bore biopsy might impact risk stratification and patient management considering the higher per-core percentage of malignant cells, especially for patients eligible for active surveillance or focal therapy.

In-Bore Versus Fusion MRI-Targeted Biopsy of PI-RADS Category 4 and 5 Lesions: A Retrospective Comparative Analysis Using Propensity Score Weighting

BACKGROUND. Few published studies have compared in-bore and fusion MRI-targeted prostate biopsy, and the available studies have had conflicting results. OBJECTIVE. The purpose of this study was to compare the target-specific cancer detection rate of in-bore prostate biopsy with that of fusion MRI-targeted biopsy. METHODS. The records of men who underwent in-bore or fusion MRI-targeted biopsy of PI-RADS category 4 or 5 lesions between August 2013 and September 2019 were retrospectively identified. PI-RADS version 2.1 assessment category, size, and location of each target were established by retrospective review by a single experienced radiologist. Patient history and target biopsy results were obtained by electronic medical record review. Only the first MRI-targeted biopsy of the dominant lesion was included for patients with repeated biopsies or multiple targets. In-bore and fusion biopsy were compared by propensity score weights and multivariable regression to adjust for imbalances in patient and target characteristics between biopsy techniques. The primary endpoint was target-specific prostate cancer detection rate. Secondary endpoints were detection rate after application of propensity score weighting for cancers in International Society of Urological Pathology (ISUP) grade group 2 (GG2) or higher and detection rate with the use of off-target systematic sampling results. RESULTS. The study sample included 286 men (in-bore biopsy, 191; fusion biopsy, 95). Compared with fusion biopsy, in-bore biopsy was associated with significantly greater likelihood of detection of any cancer (odds ratio, 2.28 [95% CI, 1.04-4.98]; p = .04) and nonsignificantly greater likelihood of detection of ISUP GG2 or higher cancer (odds ratio, 1.57 [95% CI, 0.88-2.79]; p = .12) in a target. When off-target sampling was included, in-bore biopsy and combined fusion and systematic biopsy were not different for detection of any cancer (odds ratio, 1.16 [95% CI, 0.54-2.45]; p = .71) or ISUP GG2 and higher cancer (odds ratio, 1.15 [95% CI, 0.66-2.01]; p = .62). CONCLUSION. In this retrospective study in which propensity score weighting was used, in-bore MRI-targeted prostate biopsy had a higher target-specific cancer detection rate than did fusion biopsy. CLINICAL IMPACT. Pending a larger prospective randomized multicenter comparison between in-bore and fusion biopsy, in-bore may be the preferred approach should performing only biopsy of a suspicious target, without concurrent systematic biopsy, be considered clinically appropriate.

MRI-Targeted Prostate Biopsy Techniques: AJR Expert Panel Narrative Review

Prostate cancer is the second most common malignancy in men worldwide. Systematic transrectal prostate biopsy is commonly used to obtain tissue to establish the diagnosis. However, in recent years, MRI-targeted biopsy (based on an MRI examination performed prior to consideration of biopsy) has been shown to detect more clinically significant cancer and less clinically insignificant cancer compared to systematic biopsy. This approach of performing MRI prior to biopsy has become, or is becoming, a standard of practice in centers throughout the world. This growing use of an MRI-directed pathway is leading to performance of a larger volume of MRI-targeted prostate biopsies. The three common MRI-targeted biopsy techniques are cognitive biopsy, MRI-ultrasound software fusion biopsy, and MRI in-bore guided biopsy. These techniques for using MRI information at the time of biopsy can be performed via a transrectal or transperineal approach. This narrative review presents the three MRI-targeted biopsy techniques along with their advantages and shortcomings. Comparisons among the techniques are summarized based on the available evidence. Studies to date have provided heterogeneous results, and the preferred technique remains debated.

Magnetic resonance imaging-guided prostate biopsy-A review of literature

Objective

Multiparametric magnetic resonance imaging (MP-MRI) helps to identify lesion of prostate with reasonable accuracy. We aim to describe the various uses of MP-MRI for prostate biopsy comparing different techniques of MP-MRI guided biopsy.

Materials and methods

A literature search was performed for "multiparametric MRI", "MRI fusion biopsy", "MRI guided biopsy", "prostate biopsy", "MRI cognitive biopsy", "MRI fusion biopsy systems", "prostate biopsy" and "cost analysis". The search operation was performed using the operator "OR" and "AND" with the above key words. All relevant systematic reviews, original articles, case series, and case reports were selected for this review.

Results

The sensitivity of MRI targeted biopsy (MRI-TB) is between 91%-93%, and the specificity is between 36%-41% in various studies. It also has a high negative predictive value (NPV) of 89%-92% and a positive predictive value (PPV) of 51%-52%. The yield of MRI fusion biopsy (MRI-FB) is similar, if not superior to MR cognitive biopsy. In-bore MRI-TB had better detection rates compared to MR cognitive biopsy, but were similar to MR fusion biopsy.

Conclusions

The use of MRI guidance in prostate biopsy is inevitable, subject to availability, cost, and experience. Any one of the three modalities (i.e. MRI cognitive, MRI fusion and MRI in-bore approach) can be used. MRI-FB has a fine balance with regards to accuracy, practicality and affordability.

Positive Predictive Value of Prostate Imaging Reporting and Data System Version 2 for the Detection of Clinically Significant Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

The variability of the positive predictive value (PPV) represents a significant factor affecting the diagnostic performance of multiparametric magnetic resonance imaging (mpMRI).

OBJECTIVE

To analyze published studies reporting mpMRI PPV and the reasons behind the variability of clinically significant prostate cancer (csPCa) detection rates on targeted biopsies (TBx) according to Prostate Imaging Reporting and Data System (PI-RADS) version 2 categories.

EVIDENCE ACQUISITION

A search of PubMed, Cochrane library's Central, EMBASE, MEDLINE, and Scopus databases, from January 2015 to June 2020, was conducted. The primary and secondary outcomes were to evaluate the PPV of PI-RADS version 2 in detecting csPCa and any prostate cancer (PCa), respectively. Individual authors' definitions for csPCa and PI-RADS thresholds for positive mpMRI were accepted. Detection rates, used as a surrogate of PPV, were pooled using random-effect models. Preplanned subgroup analyses tested PPV after stratification for PI-RADS scores, previous biopsy status, TBx technique, and number of sampled cores. PPV variation over cancer prevalence was evaluated.

EVIDENCE SYNTHESIS

Fifty-six studies, with a total of 16 537 participants, were included in the quantitative synthesis. The PPV of suspicious mpMRI for csPCa was 40% (95% confidence interval 36-43%), with large heterogeneity between studies (I² 94%, p < 0.01). PPV increased according to PCa prevalence. In subgroup analyses, PPVs for csPCa were 13%, 40%, and 69% for, respectively, PI-RADS 3, 4, and 5 (p < 0.001). TBx missed 6%, 6%, and 5% of csPCa in PI-RADS 3, 4, and 5 lesions, respectively. In biopsy-naïve and prior negative biopsy groups, PPVs for csPCa were 42% and 32%, respectively (p = 0.005). Study design, TBx technique, and number of sampled cores did not affect PPV.

CONCLUSIONS

Our meta-analysis underlines that the PPV of mpMRI is strongly dependent on the disease prevalence, and that the main factors affecting PPV are PI-RADS version 2 scores and prior biopsy status. A substantially low PPV for PI-RADS 3 lesions was reported, while it was still suboptimal in PI-RADS 4 and 5 lesions. Lastly, even if the added value of a systematic biopsy for csPCa is relatively low, this rate can improve patient risk assessment and staging.

PATIENT SUMMARY

Targeted biopsy of Prostate Imaging Reporting and Data System 3 lesions should be considered carefully in light of additional individual risk assessment corroborating the presence of clinically significant prostate cancer. On the contrary, the positive predictive value of highly suspicious lesions is not high enough to omit systematic prostate sampling.

The utility of in-bore multiparametric magnetic resonance-guided biopsy in men with negative multiparametric magnetic resonance-ultrasound software-based fusion targeted biopsy

OBJECTIVES

To evaluate the utility of in-bore multiparametric magnetic resonance-guided biopsy of the prostate (IB) in patients with visible lesion/s and previous negative software-based multiparametric magnetic resonance imaging/ultrasonography fusion-targeted biopsy of the prostate (FTB).

PATIENTS AND METHODS

We retrospectively analysed prospectively maintained database including consecutive men undergoing IB from March 2013 to October 2017 in 2 European centres expert in this procedure. We selected men with the following criteria: No previous treatment for prostate cancer (CaP), multiparametric magnetic resonance imaging (mpMRI) lesion(s) PIRADS score ≥ 3, FTB showing no clinically significant cancer (csCaP), and subsequent IB. Patient's characteristics, mpMRI findings, biopsy technique, and histopathological results were extracted. The primary outcome was to determine the detection rate of csCaP, defined as any Gleason pattern ≥ 4. A multivariable analysis was performed to identify predictors of positive findings at IB.

RESULTS

Fifty-three men were included. Median age was 68 years (interquartile range [IQR] 64-68), median Prostate-Specific Antigen (PSA) was 7.6 ng/ml (IQR 5.2-10.9), and median prostate volume was 59 ml (IQR 44-84). Fifty-six lesions with PIRADS score 3 in 9 cases (16%), 4 in 30 cases (54%), and 5 in 17 cases (30%) were detected. FTB was performed in all cases using a transrectal approach with 3 different platforms (Toshiba, Koelis, and Artemis). Median time between FTB and IB was 3 months (IQR 1-7). A median of 2 cores per lesion were collected with IB (IQR 2-3). No cancer, clinically insignificant and clinically significant cancer were found in 33 (59%), 9 (16%), and 14 (25%) targeted lesions, respectively. Median maximum cancer core length and maximum positive percentage were 9 mm (3-13) and 55% (21%-80%). The only predictor of csCaP on IB was prostate volume (P = 0.026) with an ideal cut-off at 70 ml.

CONCLUSION

One in 4 patients with previous negative FTB, IB was able to detect csCaP. According to this study, IB would be of particularly useful in patients with large glands.

Transperineal prostate biopsy: a review of technique

As the second most diagnosed cancer worldwide, prostate cancer is confirmed via tissue biopsy. Given the large number of prostate biopsies performed each year, the technique should be as accurate and safe as possible for the patient’s well-being. Transrectal ultrasound guided prostate biopsy (TRUS-biopsy) is most offered worldwide. Transperineal biopsy (TPP-biopsy), on the other hand, has been gaining popularity due to its superior sensitivity and lower rate of sepsis. This article offers a review of the brachytherapy grid technique used to perform a TPP-biopsy, as well as a discussion of possible variations in the procedure. TPP-biopsy is typically performed under general anaesthesia with patient in lithotomy. Through the perineum, cores of tissue are taken systematically, with or without targeting, under US guidance. Different fusion techniques (cognition, MRI-US fusion software, MRI in-bore) can be used to target pre-identified lesions on MRI. The sampling can be done either by free hand or using a brachytherapy grid. Robotic assisted prostate biopsy is also available on the market as an alternative. In recent years, there has been accumulating evidence showing that it is safe and feasible to perform TPPB under local anaesthesia. This may improve the uptake of TPPB as the preferred biopsy technique for prostate cancer.

Magnetic resonance imaging-ultrasound fusion-targeted biopsy combined with systematic 12-core ultrasound-guided biopsy improves the detection of clinically significant prostate cancer: Are we ready to abandon the systematic approach?

Background:

Multiparametric (mp) magnetic resonance imaging (MRI)–ultrasound fusion-targeted biopsy (TB) has improved the detection of clinically significant prostate cancer (csCaP) using the Prostate Imaging Reporting and Data System (PI-RADS) reporting system, leading some authors to conclude that TB can replace the 12-core systematic biopsy (SB). We compared the diagnostic performance of TB with SB at our institution.

Methods:

Eighty-three men with elevated prostate-specific antigen levels (6.6 ng/mL, interquartile range [IQR] 4.5–9.2) and abnormal mp-MRI (127 lesions, PI-RADS ≥3, median size: 1.1 cm, IQR 0.8–1.6) underwent simultaneous TB and SB. Diagnosis of any CaP (Gleason score, [GS] ≥6) and csCaP (GS ≥7) was compared using the McNemar's exact test.

Results:

SB showed higher, but not statistically significant, detection rates of any CaP and csCaP (51.8% and 34.9%) versus TB (44.6% and 28.9%) (P = 0.286 and P = 0.359, respectively). TB outperformed SB in the quantification of 56.6% CaP and detecting cancer in anterior sectors (7.2%). Compared to SB, TB missed twice the amount of any CaP and csCaP. SB alone detected 22.2% of all csCaPs and upgraded 20.6% of TB-detected CaP. SB identified cancer invisible on mp-MRI (13.7% of all CaP) or missed by TB due to a small size (<1 cm) and sampling error (7% of lesions).

Conclusion:

A combination of SB with TB remained necessary for achieving the highest cancer detection rates. Limiting prostate biopsy to TB alone can miss csCaP due to the presence of synchronous high-grade cancer invisible on MRI or failure to hit the target. TB is the best approach for anterior lesions and tumor quantification.

The role of magnetic resonance imaging-guided biopsy for diagnosis of prostate cancer; comparison between FUSION and "IN-BORE" approaches

BACKGROUND

The aim of the present study is to evaluate the difference in terms of feasibility and detection rate of two magnetic resonance imaging (MRI) guided biopsy approaches (MRI fusion versus "in-bore" MRI) in a single tertiary center.

METHODS

We retrospectively identified 297 patients with suspected prostate cancer who underwent MRI based target prostate biopsy (FUSION or "in-bore" approaches) between January 2016 and January 2018 in a single tertiary center.

RESULTS

Lesion site (peripheral vs. central) and localization (anterior vs. posterior) were equally comparable among two groups, but maximum diameter of multiparametric-MRI Index lesion was slightly superior in the in-bore MRI-GB group (14 vs. 12 mm, P=0.002). Mean random biopsy cores taken were 11.2±2.1, with 1.3±2 positive cores in FUSION-GB group. Mean number of targeted biopsy cores taken was significantly superior in the FUSION-GB group as compared to the in-bore MRI-GB group (2.6±0.7 vs.1.7±1, P<0.001), whereas mean number of positive targeted biopsy cores was comparable between two groups (1±1.3 vs.1±0.9, P=0.1). 70 (45.5%) and 75 (52.8%) patients had positive targeted bioptic cores at pathologic examination among FUSION-GB and in-bore MRI-GB groups, respectively (P=0.2). Bioptical ISUP grade was also comparable among two groups (P=0.2) in multivariate analysis PI-RADS Score (OR=3.04 and OR=8.32 for PI-RADS 4 and 5, respectively) and PSA density (OR=2.69) were identified as independent predictors of positive targeted cores at histological examination (P<0.001 and P=0.01, respectively).

CONCLUSIONS

In-bore MRI-GB approaches represent a promising technique that may offer some advantages compared to standard systematic FUSION-GB despite higher costs of in bore-procedure. Our experience, although not showing a clear advantage between the FUSION technique and the "in-bore" technique, resulted safe and feasible and represents a viable procedure for the diagnosis and characterization of prostate especially in a subgroup of patient with clinically significant disease. Further investigations are needed in order to identify the best approach for MRI-GB.

Review article: MRI-targeted biopsies for prostate cancer diagnosis and management

PURPOSE

Transrectal ultrasound (TRUS)-guided biopsy has been the traditional biopsy route in the detection of prostate cancer. However, due to concern regarding overdetection of low-risk cancer and missed clinically significant cancers as well as risk of sepsis, alternative approaches have been explored. Transperineal template biopsy-sampling the gland every 5 m to 10 mm-reduces error by sampling the whole prostate but increases risk of detecting clinically insignificant cancers as well as conferring risks of side effects such as urinary retention and bleeding.

METHODS

There are various targeted biopsy techniques, each with different cancer detection rates, costs and learning curves. Current research focuses on refining biopsy methodology to maximize detection of significant cancers, whilst minimising invasiveness and complications. In this article, the up-to-date research data about MRI-targeted prostate biopsy were reviewed to show its utilization in prostate cancer management and diagnosis.

RESULTS AND CONCLUSION

Prostate multiparametric MRI has become an effective tool in the detection of significant cancers and an essential component of the prostate cancer diagnostic pathway incorporating MRI-guided biopsy decisions.

Prostate biopsy: guidelines and evidence

PURPOSE OF REVIEW

To summarize the highest level evidence that was acquired within the last years, with regard to diagnosis of prostate cancer. With many secondary diagnostic tools becoming available, and not being mentioned in the guidelines, this review is meant to assist clinical decision-making in initial biopsy and rebiopsy settings.

RECENT FINDINGS

The PROMIS Trial delivered level 1b evidence about the diagnostic accuracy of prostate multiparametric MRI (mpMRI) as a triage tool for prostate biopsy. MRI-ultrasound-fusions-targeted biopsy has been evaluated and compared with the standard of care, and has been found to have a higher cancer detection rate. The different approaches to MRI-guided biopsies do not show significant differences. Urine biomarkers analysing RNA as well as genetic assays of biopsy specimen have also shown to be helpful in the decision to (re-)biopsy a patient, especially in combination with MRI.

SUMMARY

Patients and doctors alike have been trying to avoid prostate biopsies, the risks, and the side effects of potential overtreatment. Imaging and other biomarkers are used to increase diagnostic accuracy, yielding more precise information to act on. None of these secondary diagnostic tools are perfect, yet they can, and should be used if one stays aware of their limitations.

Prostate biopsy: when and how to perform

Prostate cancer, unlike other cancers, has been sampled in a non-targeted, systematic manner in the past three decades. On account of the low volume of prostate sampled despite the multiple cores acquired, systematic transrectal (TRUS) biopsy suffered from low sensitivity in picking up clinically significant prostate cancer. In addition, a significant number of cancers of the anterior, lateral peripheral zone, and the apex were missed as these areas were undersampled or missed during this biopsy protocol. Subsequently, the number of cores acquired was increased with special focus given to targeting the previously undersampled areas. These procedures led to an increase in the complication rates as well as detection of more clinically insignificant cancers. The advent of multiparametric magnetic resonance imaging (MRI) and its high intrinsic tissue contrast enabled better detection of prostate cancer. This led to the introduction of MRI-targeted biopsies with either MRI-TRUS fusion or under direct (in-gantry) guidance. MRI-targeted biopsies increased the percentage of positive cores and detection of clinically significant prostate cancers; however, these are expensive, time-intensive, require significant capital investment and operator expertise. This article describes the indications, workflow, complications, advantages, and disadvantages of TRUS-guided biopsy followed by MRI-guided biopsies.

Follow-up of negative MRI-targeted prostate biopsies: when are we missing cancer?

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI) has improved clinicians' ability to detect clinically significant prostate cancer (csPCa). Combining or fusing these images with the real-time imaging of transrectal ultrasound (TRUS) allows urologists to better sample lesions with a targeted biopsy (Tbx) leading to the detection of greater rates of csPCa and decreased rates of low-risk PCa. In this review, we evaluate the technical aspects of the mpMRI-guided Tbx procedure to identify possible sources of error and provide clinical context to a negative Tbx.

METHODS

A literature search was conducted of possible reasons for false-negative TBx. This includes discussion on false-positive mpMRI findings, termed "PCa mimics," that may incorrectly suggest high likelihood of csPCa as well as errors during Tbx resulting in inexact image fusion or biopsy needle placement.

RESULTS

Despite the strong negative predictive value associated with Tbx, concerns of missed disease often remain, especially with MR-visible lesions. This raises questions about what to do next after a negative Tbx result. Potential sources of error can arise from each step in the targeted biopsy process ranging from "PCa mimics" or technical errors during mpMRI acquisition to failure to properly register MRI and TRUS images on a fusion biopsy platform to technical or anatomic limits on needle placement accuracy.

CONCLUSIONS

A better understanding of these potential pitfalls in the mpMRI-guided Tbx procedure will aid interpretation of a negative Tbx, identify areas for improving technical proficiency, and improve both physician understanding of negative Tbx and patient-management options.

Value of Serial Multiparametric Magnetic Resonance Imaging and Magnetic Resonance Imaging-guided Biopsies in Men with Low-risk Prostate Cancer on Active Surveillance After 1 Yr Follow-up

BACKGROUND

Active surveillance (AS) aims to reduce overtreatment of low-risk prostate cancer (PC). Incorporating multiparametric magnetic resonance imaging (mp-MRI) and MR-guided biopsy (MRGB) in an AS protocol might contribute to more accurate identification of AS candidates.

OBJECTIVE

To evaluate the value of 3T mp-MRI and MRGB in PC patients on AS at inclusion and after 12-mo follow-up.

DESIGN, SETTING, AND PARTICIPANTS

Patients with cT1c-cT2 PC, prostate-specific antigen (PSA) ≤10ng/ml, PSA density <0.2ng/ml/ml, and Gleason scores (GSs) of ≤6 and ≤2 positive biopsy cores were included and followed in an AS protocol including mp-MRI and MRGB. The mp-MRI and MRGB were performed at <3 and 12 mo after diagnosis. Reclassification was defined as GS >6, >2 positive cores at repeat transrectal ultrasound-guided biopsy (TRUSGB), presence of PC in >3 separate cancer foci upon both MRGB and TRUSGB, or cT3 tumor on mp-MRI.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Reclassification rates, treatment after discontinuation, and outcome on radical prostatectomy after discontinuing AS were reported. Uni- and multivariate analyses were performed to identify predictors of reclassification after 1 yr.

RESULTS AND LIMITATIONS

From 2009 to 2013, a total of 111 of 158 patients were consecutively and prospectively included. Around initial diagnosis, 36 patients were excluded from the study protocol; mp-MRI+MRGB reclassified 25/111 (23%) patients, and 11 patients were excluded at own request. Reasons for reclassification were as follows: GS upgrade (15/25, 60%); cT3 disease (3/25, 12%); suspicion of bone metastases (1/25, 4%); and multifocal disease upon MRGB (6/25, 24%). Repeat examinations after 1 yr showed reclassification in 33/75 patients (44%). Reasons were the following: GS upgrade upon TRUSGB (9/33, 27%); volume progression upon TRUSGB (9/33, 27%); cT3 disease upon mp-MRI (1/33, 3%); GS upgrade upon MRGB (1/33, 3%); volume progression upon MRGB (1/33, 3%); multifocal disease upon MRGB (2/33, 6%); and upgrade or upstage upon both TRUSGB and MRGB (10/33, 30%). On logistic regression analysis, the presence of cancer at initial mp-MRI and MRGB examinations was the only predictor of reclassification after 1 yr (odds ratio 5.9, 95% confidence interval 2.0-17.6).

CONCLUSIONS

Although mp-MRI and MRGB are of additional value in the evaluation of PC patients on AS, the value of mp-MRI after 1 yr was limited. As a considerable percentage of GS ≥7 PC after 1 yr was detected only by TRUSGB, TRUSGB cannot be omitted yet.

PATIENT SUMMARY

More aggressive tumors are detected if low-risk prostate cancer patients are additionally monitored by magnetic resonance imaging. However, some high-grade tumors are detected only by transrectal ultrasound-guided biopsy.