Investigating PSMA-PET/CT to resolve prostate MRI PIRADS4-5 and negative biopsy discordance

PSMA-Targeted Biopsy With Fusion Guidance for Detecting Clinically Significant Prostate Cancer in Men With Negative MRI-Feasibility and Diagnostic Performance of a Pilot Single-Center Prospective Study

INTRODUCTION

Contemporary prostate biopsy utilizes multiparametric magnetic resonance (MRI) guidance; however, it may fail to identify a non-negligible proportion of men with clinically significant (csPCa). The main objective of this study was to assess the feasibility and diagnostic performance of Prostate Specific Membrane Antigen-Target biopsy (PSMA-TB) to diagnose csPCa in men with negative MRI and high clinical risk of PCa.

PATIENTS AND METHODS

Open-label, single-center, nonrandomized, prospective study.

INCLUSION CRITERIA

PSA density (PSAd) ≥0.2 ng/ml2 in men with PIRADS 1-2; PSA >10 ng/ml or abnormal digital rectal examination or strong familiar history for PCa or known genetic mutation. Each patients underwent PSMA-PET and transperineal fusion PSMA-TB ± systematic biopsy (SB).

RESULTS

Overall, 35 patients were enrolled; 23 (65.7%) men had positive PSMA-PET (PRIMARY score ≥3). Overall, 14 (40%) men had csPCA and 21 (60%) patients had any PCa at PSMA-TB+SB. Only 1 patient (8.3%) with negative PSMA-PET had csPCa (ISUP 3) at SB (92% Negative Predictive Value [NPV]). Fusion PSMA-TB alone detected csPCa in 12 out of 23 (52.2%) patients with positive PSMA-PET; fusion PSMA-TB with concomitant SB increased the detection of csPCa to 56.5% (added value of 4.3%). The sensitivity, specificity, Positive Predictive Value (PPV), NPV and AUC of PSMA-TB+SB were 93%, 57%, 59%, 92% and 0.75 for detection of csPCa and 91%, 79%, 86%, 95% and 0.84 for detection of any PCa, respectively. The main limitation of this study is its small sample size.

CONCLUSIONS

Fusion PSMA-TB is technically feasible and may improve the detection of csPCa in patients with negative MRI.

PSMA PET/CT in the diagnosis of prostate cancer: why and when?

Prostate-specific membrane antigen (PSMA) is expressed in most primitive and metastatic prostate cancer (PCa), and PSMA inhibitors conjugated with the radionuclides Gallium 68 (68Ga) and fluoride 18 (18F) have been evaluated to detect PCa; moreover, tumour uptake, which represents PSMA expression, is highly correlated with the aggressiveness of the primary prostatic tumour. PSMA positron emission tomography/computed tomography (PET/CT) demonstrated to be sensitive for the detection of primary prostatic lesions, regional lymphadenopathy and clinical metastases in case of biochemical recurrence. In this respect, PSMA PET/CT has been evaluated in men enrolled in clinical trials candidate to initial or repeat prostate biopsy especially in the presence of clinical high risk for PCa, Active Surveillance (AS) and/or in case of negative histology of Prostate Imaging Reporting and Data System (PI-RADS score) 4-5 targeted biopsy. Although many experimental studies reported a superimposable detection rate for PCa of PSMA PET/CT vs. mpMRI targeted biopsy, still today, the use of PSMA PET/CT is experimental and had some limitations: cost, availability, patient characteristics, local expertise and false negative rate. Although prospective and randomized studies are awaited, including a greater number of patients, PSMA PET/CT evaluation could be proposed in the presence of claustrophobia, cardiac pacemaker and severe obesity especially in men at high risk for PCa.

Incidence of Significant Prostate Cancer in the Follow-Up of Patients With Suspicious Lesion on MRI and Negative Targeted and systematic Biopsies

INTRODUCTION

Currently, there are no established guidelines for follow-up (FU) after negative prostate biopsies (PBx) despite the presence of a target on MRI. We aimed to evaluate the risk of clinically significant prostate cancer (csPCa) within 2 years (2y) and at final FU in such cases.

PATIENTS AND METHODS

We analyzed 105 patients with negative systematic and targeted PBx despite positive mpMRI (PI-RADS ≥ 3) (median FU: 66.5 months [IQR: 40-83]). All patients underwent FU with serial PSA measurements, digital rectal examinations and, when indicated, FU-MRI and/or FU-PBx. Outcomes assessed csPCa occurrence (GGG /ISUP ≥ 2) at 2y and at final FU, and predictive factors for csPCa.

RESULTS

At 2y, the csPCa detection rate (Det-R) was 7.6%, increasing to 15.2% at final FU. No significant differences were observed at 2y based on baseline PI-RADS status. The mean initial PSAD was significantly higher in patients with csPCa at 2y versus without: 0.20 ng/mL² (SD: 0.11) versus 0.13 ng/mL² (SD: 0.12) (P = .008). Patients with baseline PSAD > 0.15 had a significantly higher 2y csPCa Det-R versus with PSAD < 0.15: 18.2% (4/22) versus 3.7% (3/81) (P = .036). The combination of PSAD < 0.15 and PI-RADS 3 at baseline was associated with a very low 2y csPCa Det-R (3%, 1/34), compared to PSAD > 0.15 and PI-RADS ≥ 4 (23%, 3/13). At final follow-up: 53% of patients with csPCa had an increasing PSAD (vs. 14% without, P = .003). A total of 41% (43/105) of patients underwent FU-MRI. Patients with csPCa were significantly more likely to have upgraded MRI findings (56% vs. 2.2%, P < .001).

CONCLUSION

Following negative PBx despite a positive mpMRI, the risk of csPCa was low. However, careful monitoring is essential, particularly in cases of PSAD > 0.15, and/or PI-RADS ≥ 4 at baseline. FU-PSAD and FU-MRI emerged as the most significant predictive factors, aiding to stratify the need for FU-PBx.

Diagnostic Accuracy of PSMA PET-Guided Prostate Biopsy in Prostate Cancer-A Systematic Review and Meta-analysis

PURPOSE

Early diagnosis and treatment of prostate cancer (PC) are crucial for effective management and improved patient outcomes. Newer imaging modalities like prostate-specific membrane antigen PET have shown superior diagnostic performance in detecting PC and clinically significant PC (csPC). This systematic review and meta-analysis aims to synthesize evidence on the diagnostic performance of PSMA PET-guided prostate biopsy in detecting PC and csPC.

PATIENTS AND METHODS

The study followed the PRISMA-DTA guidelines. Using a predefined search strategy, 3 databases (PubMed, Embase, and Web of Science) were systematically searched using appropriate keywords. A meta-analysis was conducted using diagnostic accuracy parameters of the included studies. Risk of bias assessment was done using the QUADAS-2 tool.

RESULTS

Out of 378 articles, 20 were assessed for full-text screening and 10 articles with 874 patients were finally included. Eight studies reported a pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of 0.90 (95%confidence interval [CI], 0.82-0.95), 0.93 (95% CI, 0.57-0.99), 12.3 (95% CI, 1.5-98.9), 0.10 (95% CI, 0.05-0.20), and 117 (95% CI, 12-1178), respectively, for detecting PC using PSMA PET-guided prostate biopsy with an area under the summary receiver operating characteristics curve of 0.94 (95% CI, 0.92-0.96). Similarly, 6 studies reported a pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of 0.89 (95% CI, 0.82-0.94), 0.65 (95% CI, 0.49-0.79), 2.6 (95% CI, 1.6-4.1), 0.17 (95% CI, 0.09-0.31), and 15 (95% CI, 6-41), respectively, for detecting csPC using PSMA PET-guided prostate biopsy with area under summary receiver operating characteristics curve of 0.86 (95% CI, 0.82-0.88).

CONCLUSIONS

PSMA PET-guided prostate biopsy has a high diagnostic accuracy in detecting PC and csPC in patients with clinical suspicion of PC, and provides a 1-stop solution for early diagnosis and staging of PC.

Fluorine-18-labelled Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography or Magnetic Resonance Imaging to Diagnose and Localise Prostate Cancer. A Prospective Single-arm Paired Comparison (PEDAL)

BACKGROUND AND OBJECTIVE

Multiparametric magnetic resonance imaging (mpMRI) of the prostate is used for prostate cancer diagnosis. However, mpMRI has lower sensitivity for small tumours. Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT) offers increased sensitivity over conventional imaging. This study aims to determine whether the diagnostic accuracy of 18F-DCFPyL PSMA-PET/CT was superior to that of mpMRI for detecting prostate cancer (PCa) at biopsy.

METHODS

Between 2020 and 2021, a prospective multicentre single-arm phase 3 imaging trial enrolled patients with clinical suspicion for PCa to have both mpMRI and PSMA-PET/CT (thorax to thigh), with reviewers blinded to the results of other imaging. Multiparametric MRI was considered positive for Prostate Imaging Reporting and Data System (PIRADS) 3-5. PSMA-PET/CT was assessed quantitatively (positive maximum standardised uptake value [SUVmax] >7) and qualitatively (five-point lexicon of certainty). Patients underwent targeted and systematic biopsy, with the technique at the discretion of the treating urologist. Clinically significant PCa (csPCa) was defined as International Society of Urological Pathology grade group (GG) ≥2. The primary outcome was the diagnostic accuracy for detecting PCa, reported as sensitivity, specificity, negative predictive value (NPV), and area under the curve (AUC) of the receiver operating curve. The secondary endpoints included a comparison of the diagnostic accuracy for detecting csPCa, assessing gains in combining PMSA-PET/CT with mpMRI to mpMRI alone.

KEY FINDINGS AND LIMITATIONS

Of the 236 patients completing both mpMRI and PSMA-PET/CT, 184 (76.7%) had biopsy. Biopsy histology was benign (n = 73), GG 1 (n = 27), and GG ≥2 (n = 84). The diagnostic accuracy of mpMRI for detecting PCa (AUC 0.76; 95% confidence interval [CI] 0.69, 0.82) was higher than that of PSMA-PET/CT (AUC 0.63; 95% CI 0.56, 0.70, p = 0.03). The diagnostic accuracy of mpMRI for detecting csPCa (AUC 0.72; 95% CI 0.67, 0.78) was higher than that of PSMA-PET/CT (AUC 0.62; 95% CI 0.55, 0.69) but not statistically significant (p = 0.27). A combination of PSMA-PET/CT and mpMRI showed excellent sensitivity (98.8%, 95% CI 93.5%, 100%) and NPV (96%, 95% CI 79.6%, 99.9%) over mpMRI alone (86.9% and 80.7%, respectively, p = 0.01). Thirty-two patients (13.6%) had metastatic disease. They tended to be older (68.4 vs 65.1 yr, p = 0.023), and have higher prostate-specific antigen (PSA; median PSA 9.6 vs 6.2ng/ml, p < 0.001) and abnormal prostate on digital rectal examination (78.2% vs 44.1%, p < 0.001).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Multiparametric MRI had superior diagnostic accuracy to PSMA-PET/CT for detecting PCa, though the difference is not significant in case of csPCa detection. A combination of mpMRI and PSMA-PET/CT showed improved sensitivity and NPV. PSMA-PET/CT could be considered for diagnostic use in patients unable to have mpMRI or those with concerning clinical features but negative mpMRI.

PATIENT SUMMARY

In this trial, we compared the ability of 18F-labelled prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT) with that of multiparametric magnetic resonance imaging (mpMRI) to diagnose prostate cancer by biopsy in a prostate-specific antigen screening population. We found that MRI was superior to PSMA to diagnose prostate cancer, though there was no difference in ability to diagnose clinically significant prostate cancer. PSMA-PET/CT could be considered for diagnostic use in patients unable to have mpMRI or those with concerning clinical features but negative mpMRI. Combining MRI with PSMA-PET increases the negative predictive value over MRI alone and may help men avoid invasive prostate biopsy.

Natural history of histologically benign PIRADS 4-5 lesions in multiparametric MRI: Real-life experience in an academic center

INTRODUCTION

The follow-up findings of patients who underwent prostate biopsy for prostate image reporting and data system (PIRADS) 4 or 5 multiparametric magnetic resonance imaging (mpMRI) findings and had benign histology were retrospectively reviewed.

METHODS

There were 190 biopsy-naive patients. Patients with at least 12 months of follow-up between 2012 and 2023 were evaluated. All MRIs were interpreted by two very experienced uroradiologists. Of the patients, 125 had either cognitive or software fusion MR-targeted biopsies with 4 + 8/10 cores. The remaining 65 patients had in-bore biopsies with 4-5 cores. Prostate-specific antigen (PSA) levels below 4 ng/mL were defined as PSA regression following biopsy. PIRADS 1-3 lesions on new MRI images were classified as MRI regression.

RESULTS

Median patient age and PSA were 62 (39-82) years and six (0.4-33) ng/mL, respectively, at the initial work-up. During a median follow-up period of 44 months, 37 (19.4%) patients were lost to follow-up. Of the remaining 153 patients, 82 (53.6%) had persistently high PSA. Among them, 72 (87.8%) had repeat mpMRI within 6-24 months which showed regressive findings (PIRADS 1-3) in 53 patients (73.6%) and PIRADS 4-5 index lesion persistence in 19 cases (26.4%). The latter group was recommended to have rebiopsy. Of these 19 patients, 16 underwent MRI-targeted rebiopsy. Prostate cancer was diagnosed in six (37.5%) patients and of these four (25%) were clinically significant (>Grade Group 1). Totally, clinically significant prostate cancer was detected in 4/153 (2.6%) patients followed up.

CONCLUSION

Patients should be warned against the relative relaxing effect of a negative biopsy after identification of PIRADS 4-5 index lesion. While PSA decrease was observed in many patients during follow-up, persistent MRI findings were present in nearly a quarter of patients with persistently high PSA. A rebiopsy is warranted in these patients, with significant prostate cancer diagnosed in a quarter of patients with rebiopsy.

Enhancing prostate cancer diagnosis and reducing unnecessary biopsies with [18F]DCFPyL PET/CT imaging in PI-RADS 3/4 patients

For patients presenting with prostate imaging reporting and data system (PI-RADS) 3/4 findings on magnetic resonance imaging (MRI) examinations, the standard recommendation typically involves undergoing a biopsy for pathological assessment to ascertain the nature of the lesion. This course of action, though essential for accurate diagnosis, invariably amplifies the psychological distress experienced by patients and introduces a host of potential complications associated with the biopsy procedure. However, [18F]DCFPyL PET/CT imaging emerges as a promising alternative, demonstrating considerable diagnostic efficacy in discerning benign prostate lesions from malignant ones. This study aims to explore the diagnostic value of [18F]DCFPyL PET/CT imaging for prostate cancer in patients with PI-RADS 3/4 lesions, assisting in clinical decision-making to avoid unnecessary biopsies. 30 patients diagnosed with PI-RADS 3/4 lesions through mpMRI underwent [18F]DCFPyL PET/CT imaging, with final biopsy pathology results as the "reference standard". Diagnostic performance was assessed through receiver operating characteristic (ROC) analysis, evaluating the diagnostic efficacy of molecular imaging PSMA (miPSMA) visual analysis and semi-quantitative analysis in [18F]DCFPyL PET/CT imaging. Lesions were assigned miPSMA scores according to the prostate cancer molecular imaging standardized evaluation criteria. Among the 30 patients, 13 were pathologically confirmed to have prostate cancer. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of visual analysis in [18F]DCFPyL PET/CT imaging for diagnosing PI-RADS 3/4 lesions were 61.5%, 88.2%, 80.0%, 75.0%, and 76.5%, respectively. Using SUVmax 4.17 as the optimal threshold, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosis were 92.3%, 88.2%, 85.7%, 93.8%, and 90.0%, respectively. The area under the ROC curve (AUC) for semi-quantitative analysis was 0.94, significantly higher than visual analysis at 0.80. [18F]DCFPyL PET/CT imaging accurately diagnosed benign lesions in 15 (50%) of the PI-RADS 3/4 patients. For patients with PI-RADS 4 lesions, the positive predictive value of [18F]DCFPyL PET/CT imaging reached 100%. [18F]DCFPyL PET/CT imaging provides potential preoperative prediction of lesion nature in mpMRI PI-RADS 3/4 patients, which may aid in treatment decision-making and reducing unnecessary biopsies.

Negative biopsy histology in men with PI-RADS score 5: is it useful PSMA PET/CT evaluation?

INTRODUCTION

To evaluate the accuracy of PSMA PET/CT in men with mpMRI PI-RADS score 5 negative biopsy histology.

MATERIALS AND METHODS

From January 2011 to January 2023, 180 men with PI-RADS score 5 underwent systematic plus mpMRI/TRUS biopsy; 25/180 (13.9%) patients had absence of cancer and six months from biopsy were submitted to: digital rectal examination, PSA and PSA density exams, mpMRI and 68GaPSMA PET/CT evaluation (standardized uptake value "SUVmax" was reported).

RESULTS

In 24/25 (96%) patients PSA and PSA density significantly decreased, moreover, the PI-RADS score was downgraded resulting < 3; in addition, median SUVmax was 7.5. Only 1/25 (4%) man had an increased PSA value (from 10.5 to 31 ng/ml) with a confirmed PI-RADS score 5, SUVmax of 32 and repeated prostate biopsy demonstrating a Gleason score 9/ISUP Grade Group 5 PCa.

CONCLUSIONS

The strict follow up of men with PI-RADS score 5 and negative histology reduce the risk of missing csPCa especially if PSMA PET/CT evaluation is in agreement with downgrading of mpMRI (PI-RADS score < 3).

PSMA PET/CT Versus mpMRI for the Detection of Clinically Significant Prostate Cancer: An Updated Overview

In the last years, PSMA-PET imaging and multiparametric MRI (mpMRI) have improved the clinical management of prostate cancer (PCa) patients. Currently, mpMRI is recommended by the EAU (European Association of Urology) guidelines for the primary diagnosis of PCa, whereas PSMA-PET is reserved for disease staging, particularly in high risk localized or locally advanced disease, as well as for biochemical recurrence after surgery. Nevertheless, several studies have explored the added value of PSMA-PET in other clinical scenarios, including primary diagnosis and especially for the detection of clinically significant PCa (csPCa). In the present contribution, we will provide an overview and an update on the current literature on imaging detection of csPCa, with a particular focus on mpMRI, PSMA-PET and their comparison.

Re-defining 18 F-DCFPyl prostate-specific membrane antigen positron emission tomography detected local recurrence from radical prostatectomy histopathology

OBJECTIVE

To assess topographic concordance between the histopathological features of patients' radical prostatectomy (RP) specimens and the location of the prostate-specific membrane antigen positron emission tomography (PSMA PET) local recurrences, qualitatively and quantitatively.

PATIENTS AND METHODS

Our cohort was selected from the 100 men who received a 18 F-DCFPyL PET scan in the IMPPORT trial (Australian New Zealand Clinical Trials Registry Number: ACTRN12618001530213), a prospective non-randomised study completed by GenesisCare Victoria. Eligibility included patients with a rising prostate-specific antigen (PSA) level (>0.2 ng/mL) after RP and PSMA PET detected local recurrence. Histopathological parameters collated included the location of tumour, extraprostatic extension (EPE), and positive margins. Criteria for the location and 'concordance' between histopathological features and local recurrences were pre-defined.

RESULTS

A total of 24 patients were eligible; the median age was 71 years, the median PSA level was 0.37 ng/mL, and the time between RP and PSMA PET was 2.6 years. In all, 15 patients had recurrences within the vesicourethral anastomotic region and nine within the lateral surgical margins. There was 100% concordance in the left-right plane between tumour location and local recurrence, with 79% of these lesions concordant three-dimensionally; across craniocaudal, left-right, and anterior-posterior planes. In all, 10 of the 16 (63%) patients with EPE and five of the nine patients with positive margins had three-dimensional concordance between their pathology and their local recurrence. In quantitative assessment, 17 of the 24 patients, had local recurrences that correlated with the location of their original tumour in the craniocaudal plane.

CONCLUSION

Local recurrence is highly concordant with the position of the tumour within the prostate. Predicting the location of local recurrence using the location of the EPE and positive margins is less helpful. Further investigation into this field, could impact surgical technique and salvage radiotherapy clinical target volume.

Advances in Urological Cancer in 2022, from Basic Approaches to Clinical Management

This Special Issue includes 12 articles and 3 reviews dealing with several basic and clinical aspects of prostate, renal, and urinary tract cancer published during 2022 in Cancers, and intends to serve as a multidisciplinary chance to share the last advances in urological neoplasms [...].