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

The influence of the operator's experience on the outcomes of fusion prostate biopsy

Introduction

Magnetic resonance imgaing (MRI) targeted biopsy is the gold standard for prostate cancer (PCa) diagnosis. In this study, we examined the association between the operator's experience and the improvement in the precision of the MRI prostate biopsy procedure and the detection of PCa.

Material and methods

We included consecutive patients who underwent prostate fusion biopsy. Data on biopsy duration, prostate-specific antigen (PSA) value, lesion size, number of samples taken, number of cores involved, and International Society of Urological Pathology (ISUP) grade were subjected to statistical analysis, with the study group divided into three consecutive time periods (tertiles).

Results

There were statistically significant differences in biopsy duration between tertiles (p <0.001). The greatest difference in the involved/taken cores ratio occurred between the first and third tertile (p = 0.002). The difference between the first and second tertile was insignificant (p = 0.4), while the difference between the second and third tertile was statistically significant (p = 0.004). The differences between tertiles in Prostate Imaging and Reporting Data System v2.1 were also significant (p = 0.003). The PSA value (p = 0.036) was statistically significant, unlike prostate volume (p = 0.16), digital rectal examination (DRE) (p = 0.7), and ISUP grade (p = 0.7). There was no statistical difference between tested tertiles in the number of detected PCa ISUP ≥2 (Z = 0.191; p = 0.8).

Conclusions

The abilities and precision of the operator increase with the increase in the number of procedures performed. The biopsy duration is shortened, and the detection of PCa during the procedure seems to improve with the operator's experience.

ACR Appropriateness Criteria® Pretreatment Detection, Surveillance, and Staging of Prostate Cancer: 2022 Update

Prostate cancer is second leading cause of death from malignancy after lung cancer in American men. The primary goal during pretreatment evaluation of prostate cancer is disease detection, localization, establishing disease extent (both local and distant), and evaluating aggressiveness, which are the driving factors of patient outcomes such as recurrence and survival. Prostate cancer is typically diagnosed after the recognizing elevated serum prostate-specific antigen level or abnormal digital rectal examination. Tissue diagnosis is obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy, commonly with multiparametric MRI without or with intravenous contrast, which has recently been established as standard of care for detecting, localizing, and assessing local extent of prostate cancer. Although bone scintigraphy and CT are still typically used to detect bone and nodal metastases in patients with intermediate- or high-risk prostate cancer, novel advanced imaging modalities including prostatespecific membrane antigen PET/CT and whole-body MRI are being more frequently utilized for this purpose with improved detection rates. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Determination of Gleason score discrepancy for risk stratification in magnetic resonance-ultrasound fusion prostate biopsy

BACKGROUND

Magnetic resonance imaging (MRI)-ultrasound (US) fusion biopsy remains challenging and highlights the need towards standardization.

PURPOSE

To characterize the clinical and MRI features of clinically significant prostate cancer (csPCa) with discrepant Gleason score (GS) in MRI-US fusion biopsy.

MATERIAL AND METHODS

A total of 400 consecutive patients with suspected cancer lesions who underwent MRI-US fusion biopsy and subsequent prostatectomy were included. In the comparison of biopsy GS with pathology GS, matched lesions were defined as a GS, and discrepant lesions were defined as an upgrade of the GS. Descriptive statistics were used to define clinical characteristics, including age, prostate-specific antigen (PSA), PSA density, and maximal cancer core length (MCCL). Differences between lesions with matched and discrepant GS were determined considering the location and PI-RADS v2 score. A paired comparison of the volumes between the two groups was performed.

RESULTS

There were 130 lesions with discrepant GS in 124 patients. There was no significant difference in the age, PSA, and PSA density between the two groups, except for the MCCL (P = 0.028). The lesions were distributed in the peripheral (n = 88) and transition (n = 42) zones; 33, 50, and 47 lesions were at the apex, mid-gland, and base levels, respectively. PI-RADS scores were as follows: 2 (n = 5), 3 (n = 8), 4 (n = 68), and 5 (n = 39). In comparison with matched lesions, discrepant lesions had significantly smaller multiparametric MRI-measured cancer volumes (P < 0.05).

CONCLUSION

Knowledge of discrepant GS in MRI-US fusion biopsy is important, and a careful approach is needed to reduce this discrepancy.

Fusion prostate biopsy outperforms 12-core systematic prostate biopsy in patients with prior negative systematic biopsy: A multi-institutional analysis

INTRODUCTION AND OBJECTIVES

Patients with persistently elevated prostate specific antigen (PSA) and prior negative 12-core TRUS prostate biopsy (or biopsies) (systematic biopsy-SBx) are a diagnostic challenge. Repeat SBx or saturation biopsy in this cohort has been shown to have an even lower yield. The aim of our study is to compare the prostate cancer yield of magnetic resonance imaging (MRI) fusion biopsy (FBx) to SBx in a multi-institutional cohort comprised of patients with prior negative biopsies.

METHODS

A multi-institutional review was performed on patients with a history of one or more prior negative SBx who underwent multiparametric MRI (mpMRI), followed by FBx and SBx in the same session. Imaging protocol was standardized across institutions and institutional genitourinary radiologists and pathologists reviewed mpMRI and pathology, respectively. Gleason score (GS) distribution and risk classifications were recorded. Prostate cancer with GS ≥3 + 4 was defined as clinically significant (CS). Univariate and multivariable logistic regression was done to identify predictors of cancer detection on SBx and FBx.

RESULTS

Seven-hundred seventy-nine patients from four institutions were included in the study. Median age and prostate specific antigen (IQR) were 63.1 (58.5-68.0) years and 8.5 (5.9-13.1)ng/dl, respectively. Median number of prior negative biopsies (range) was 2.0 (1-16). The cancer detection rate (CDR) in the cohort was 346/779 patients (44.4%). Total CS CDR was 30.7% (239/779 patients), with FBx detecting 26.3% (205/779) of patients with CS disease and SBx diagnosing an additional 4.4% (34/779) of patients (P<0.001). Furthermore, of all cancers detected by each modality, FBx detected a higher proportion of CS cancer compared to SBx (one negative biopsy: 75 vs. 50%, P<0.001, 2-3 negative biopsy: 76 vs. 61%, P = 0.006, 4 or more negative biopsies: 84 vs. 52%, P = 0.006). As such, SBx added a relatively small diagnostic value to FBx for detecting CS disease (one negative biopsy 3.5%, 2-3 negative biopsies 5%, 4 or more negative biopsies: 1%). FBx also outperformed SBx for upgrading patients to an intermediate or high-risk cancer category (GS>6) (one negative biopsy 11.5% vs. 3.6%, 2-3 negative biopsy 10.3% vs. 5.3%, 4 or more negative biopsies 19.1% vs. 1.1%). On multivariable analysis, the number of prior negative biopsies was a significant negative predictor of CS CDR on SBx (P = 0.006), but not on FBx (P = 0.151).

CONCLUSIONS

Using a large multi-institutional cohort, we were able to demonstrate that FBx outperformed SBx in patients with prior negative systematic biopsy. This was due, in part, to the decreasing CS CDR by SBx with increased number of prior biopsies. The yield of FBx stayed constant and did not decrease with increased number of prior negative biopsies. Therefore, repeat SBx alone in patients with multiple prior negative biopsies will be hindered by lower yield and FBx should be utilized concurrently in these patients.

Incidental findings on multiparametric MRI performed for evaluation of prostate cancer

PURPOSE

Multiparametric magnetic resonance imaging (mp-MRI) and MRI/Ultrasound (US) fusion-guided biopsy are relatively new techniques for improved detection, staging, and active surveillance of prostate cancer (PCa). As with all imaging modalities, MRI reveals incidental findings (IFs) which carry the risk of increased cost, patient anxiety, and iatrogenic morbidity due to workup of IFs. Herein, we report the IFs from 684 MRIs for evaluation of PCa and consider their characteristics and clinical significance.

METHODS

Patients underwent mp-MRI prostate protocol incorporating triplanar T2-weighted, diffusion-weighted, and dynamic contrast-enhanced pelvic MRI as well as a post-contrast abdominopelvic MRI with the primary indication of detection or evaluation of PCa. A total of 684 consecutive prostate MRI reports performed in a series of 580 patients were reviewed. All extraprostatic findings reported were logged and then categorized by organ system and potential clinical significance.

RESULTS

There were 349 true IFs found in 233 (40%) of the 580 patients. One hundred nineteen additional extraprostatic findings were unsuspected but directly related to PCa staging, while the 349 IFs were unrelated and thus truly incidental beyond study indication. While the majority of true IFs were non-urologic, only 6.6% of IFs were considered clinically significant, non-urologic findings, and more than a third of MRI reports had urologic IFs not related to PCa.

CONCLUSIONS

Rates of incidental findings on prostate indication MRI are similar to other abdominopelvic imaging studies. However, only 6.6% of the IFs were considered to be clinically significant non-urologic findings. Further investigations are needed to assess downstream workup of these IFs and resulting costs.

3-T multiparametric MRI characteristics of prostate cancer patients suspicious for biochemical recurrence after primary focal cryosurgery (hemiablation)

INTRODUCTION

We aimed to report on multiparametric MRI (mpMRI) characteristics of post-primary focal cryosurgery (PFC) patients suspected of biochemical recurrence (BCR) by the Phoenix criteria.

METHODS

We retrospectively reviewed all patients at our institution who had undergone PFC. Prostate-specific antigen nadir was determined using 2 or more post-PFC values. Suspicion of BCR was determined using the Phoenix criteria (nadir + 2 ng/ml). At the discretion of the physician, pre-and post-PFC 3-T mpMRIs were obtained and in a few cases biopsies were performed.

RESULTS

Ninety (58.4%) of 154 consecutive patients who underwent PFC were included in our analysis and had a median (range) age and prostate volume of 66.5 (48-82) years and 40.5 (16-175) ml, respectively. Of those suspected of BCR (37/90, 41.1%), with a median time to BCR of 19.9 (7.0-38.5) months, 27 patients (73.0%) underwent a post-PFC mpMRI. Twenty-two (81.5%) of these mpMRIs were found with 24 suspicious lesions. A considerable number (9/24, 37.5%) of these lesions were located in the central gland of the prostate. Seven of 24 lesions exhibited adverse mpMRI characteristic; 4 (16.7%) had capsular contact, 2 (8.2%) showed frank extracapsular extension, and 1 (4.2%) showed seminal vesicle invasion. Five (45.5%) of 11 patients with positive post-PFC mpMRIs were positive on biopsy (4/5, 80% were clinically significant prostate cancer).

CONCLUSION

Post-PFC mpMRI, at Phoenix suspicion of BCR, may help identify a significant number of patients failing post-PFC.

From novice to expert: analyzing the learning curve for MRI-transrectal ultrasonography fusion-guided transrectal prostate biopsy

PURPOSE

To investigate the learning curve of a novice in MRI/TRUS software fusion biopsy and to compare his results with the expert standard at our institution.

METHODS

Overall 126 MRI/TRUS fusion-guided transrectal biopsies were performed using an electromagnetic tracking ultrasonography platform. The learning progress of the novice was evaluated comparing his initial 42 procedures (group A) with his following 42 (group B). The institution's expert standard (group C), which was compared to the novice's groups, was defined by the expert's experience of 42 MRI/TRUS fusion biopsies. Primary learning curve parameters were targeted biopsy detection quotient and biopsy time.

RESULTS

Overall detection of prostate cancer was 64% (27/42), 62% (26/42) and 62% (26/42) in groups A, B and C, respectively. The median target biopsy detection quotient significantly increased (p = 0.04) in group B (0.75, interquartile range (IQR) 0.25-1.0) compared to group A. (0.33, IQR 0.2-0.5). Group C revealed a median detection quotient of 0.5 (IQR 0.25-0.76) that did not differ significantly from the novice's groups (p = 0.2). Median biopsy time was significantly higher in group A (45 min, IQR 33-50 min) compared to groups B (25 min, IQR 23-29 min) and C (24 min, IQR 16-46 min) (p < 0.01).

CONCLUSIONS

The present study revealed the individual learning curve of a novice in MRI/TRUS fusion biopsy and demonstrated significant learning progress regarding targeted biopsy detection quotient and biopsy time.

A critical comparison of techniques for MRI-targeted biopsy of the prostate

MRI-targeted biopsy is a promising technique that offers an improved detection of clinically significant prostate cancer over standard non-targeted biopsy. It is established that prostate MRI is of use in both the primary and repeat biopsy setting for the detection of significant prostate cancer. There are three approaches to targeting biopsies to areas of interest seen on prostate MRI. They each rely on the acquisition and reporting of a diagnostic quality multi-parametric MRI scan used to identify areas of interest, and the subsequent use of those diagnostic quality images in combination with real-time images of the prostate during the biopsy procedure. The three techniques are: visual registration of the MRI images with a real-time ultrasound image; software-assisted fusion of the MRI images and the real-time ultrasound images, and in-bore biopsy, which requires registration of a diagnostic quality MRI scan with a real time interventional MRI image. In this paper we compare the three techniques and evaluate those studies where there is a direct comparison of more than one MRI-targeting technique. PubMed was searched from inception to November 2016 using the search terms (cognitive registration OR visual registration OR fusion biopsy OR in-bore biopsy OR targeted biopsy) AND (prostate cancer OR prostate adenocarcinoma OR prostate carcinoma OR prostatic carcinoma OR prostatic adenocarcinoma) AND (MRI OR NMR OR magnetic resonance imaging OR mpMRI OR multiparametric MRI). The initial search included 731 abstracts. Eleven full text papers directly compared two or more techniques of MRI-targeting, and were selected for inclusion. The detection of clinically significant prostate cancer varied from 0% to 93.3% for visual registration, 23.2% to 100% for software-assisted registration and 29% to 80% for in-bore biopsy. Detection rates for clinically significant cancer are dependent on the prevalence of cancer within the population biopsied, which in turn is determined by the selection criteria [biopsy naïve, previous negative biopsy, prostate specific antigen (PSA) selection criteria, presence of a lesion on MRI]. Cancer detection rates varied more between study populations than between biopsy approaches. Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. Although there have been studies supporting each of the three techniques, substantial differences in methodology and reporting the findings make it difficult to reliably compare their outcomes.

Current beliefs and practice patterns among urologists regarding prostate magnetic resonance imaging and magnetic resonance-targeted biopsy

INTRODUCTION AND OBJECTIVE

Multiparametric magnetic resonance imaging (MRI) and magnetic resonance (MR) -targeted biopsy have a growing role in the screening and evaluation of prostate cancer. We aim to evaluate the current knowledge, attitude, and practice patterns of urologists regarding this new technique.

METHODS

An anonymous online questionnaire was designed to collect information on urologists' beliefs and use of prostate multiparametric MRI and MR-targeted biopsy. The survey was sent to members of the Society of Urologic Oncology, the Endourological Society, and European Association of Urology. Multivariate logistic regression analysis was performed to determine predictors for use of prostate MRI and MR-targeted biopsy.

RESULTS

A total of 302 responses were received (Endourological Society: 175, European Association of Urology: 23, and Society of Urologic Oncology: 104). Most respondents (83.6%) believe MR-targeted biopsy to be moderately to extremely beneficial in the evaluation of prostate cancer. Overall, 85.7% of responders use prostate MRI in their practice, and 63.0% use MR-targeted biopsy. The 2 most common settings for use of MR-targeted biopsy include patients with history of prior negative biopsy result (96.3%) and monitoring patients on active surveillance (72.5%). In those who do not use MR-targeted biopsy, the principal reasons were lack of necessary infrastructure (64.1%) and prohibitive costs (48.1%). On multivariate logistic regression analysis, practice in an academic setting (1.86 [1.02-3.40], P = 0.043) and performing greater than 25 radical prostatectomies per year (2.32 [1.18-4.56], P = 0.015) remained independent predictors for using MR-targeted biopsy.

CONCLUSIONS

Most respondents of our survey look favorably on use of prostate MRI and MR-targeted biopsy in clinical practice. Over time, reduction in fixed costs and easier access to equipment may lead to further dissemination of this novel and potentially transformative technology.