Targeted Biopsy in Men High Risk for Prostate Cancer: 68Ga-PSMA PET/CT Versus mpMRI

Optimising prostate biopsies and imaging for the future-a review

Conventionally, transrectal ultrasound guided prostate biopsy (TRUS-Bx) was the main technique used for the diagnosis of prostate cancer since it was first described in 1989 [1]. However, the PROMIS trial showed that this random, nontargeted approach could miss up to 18% of clinically significant cancer (csPCa) [2]. Furthermore, risk of sepsis post TRUS-Bx can be as high as 2.4% [3]. Understanding the demerits of TR-biopsy have led to the introduction of transperineal prostate biopsy (TP-Bx). The incorporation of mpMRI revolutionized prostate cancer diagnostics, allowing visualization of areas likely to harbor csPCa whilst permitting some men to avoid an immediate biopsy. Furthermore, the advent of prostate specific membrane antigen-positron emission tomography (PSMA-PET) is highly promising, because of its role in primary diagnosis of prostate cancer and its higher diagnostic accuracy over conventional imaging in detecting nodal and metastatic lesions. Our narrative review provides an overview on prostate biopsy techniques and an update on prostate imaging, with particular focus on PSMA-PET.

Preliminary clinical practice of radical prostatectomy without preoperative biopsy

BACKGROUND

At present, biopsy is essential for the diagnosis of prostate cancer (PCa) before radical prostatectomy (RP). However, with the development of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) and multiparametric magnetic resonance imaging (mpMRI), it might be feasible to avoid biopsy before RP. Herein, we aimed to explore the feasibility of avoiding biopsy before RP in patients highly suspected of having PCa after assessment of PSMA PET/CT and mpMRI.

METHODS

Between December 2017 and April 2022, 56 patients with maximum standardized uptake value (SUVmax) of ≥4 and Prostate Imaging Reporting and Data System (PI-RADS) ≥4 lesions who received RP without preoperative biopsy were enrolled from two tertiary hospitals. The consistency between clinical and pathological diagnoses was evaluated. Preoperative characteristics were compared among patients with different pathological types, T stages, International Society of Urological Pathology (ISUP) grades, and European Association of Urology (EAU) risk groups.

RESULTS

Fifty-five (98%) patients were confirmed with PCa by pathology, including 49 (89%) with clinically significant prostate cancer (csPCa, defined as ISUP grade ≥2 malignancy). One patient was diagnosed with high-grade prostatic intraepithelial neoplasia (HGPIN). CsPCa patients, compared with clinically insignificant prostate cancer (cisPCa) and HGPIN patients, were associated with a higher level of prostate-specific antigen (22.9 ng/mL vs. 10.0 ng/mL, P = 0.032), a lower median prostate volume (32.2 mL vs. 65.0 mL, P = 0.001), and a higher median SUVmax (13.3 vs. 5.6, P <0.001).

CONCLUSIONS

It might be feasible to avoid biopsy before RP for patients with a high probability of PCa based on PSMA PET/CT and mpMRI. However, the diagnostic efficacy of csPCa with PI-RADS ≥4 and SUVmax of ≥4 is inadequate for performing a procedure such as RP. Further prospective multicenter studies with larger sample sizes are necessary to confirm our perspectives and establish predictive models with PSMA PET/CT and mpMRI.

68Ga-PSMA PET/CT and 18F-FDG PET/CT in the diagnosis of prostatic ductal cancer

PURPOSES

To explore the characteristics of PSMA PET/CT and FDG PET/CT images in prostatic ductal adenocarcinoma (DA) patients.

METHODS

We retrospectively enrolled prostatic DA patients with PET/CT scans at Tongji Hospital from 2018 to 2022. Patients with prostatic acinar adenocarcinoma (AA) and benign pathology (BP) were enrolled by 1:1 matching. Differences in the uptake of primary and metastatic foci on PET among the groups were analyzed.

RESULTS

A total of 42 patients were enrolled: 14 in each group. In primary foci, the mean PSMA uptake in the DA group was lower than that in the AA group (14.2 ± 9.6 vs. 27.1 ± 14.3, P = 0.009) and greater than that in the BP group (14.2 ± 9.6 vs. 4.7 ± 1.3, P = 0.003). The AUCs of the DA-AA ROC curve and DA-BP ROC curve were 0.781 and 0.872, respectively. The median PSMA uptake of metastatic lymph nodes in the DA group was lower than that in the AA group (5.6 vs. 14.2, P = 0.033), with no significant difference in metastatic bone lesions (9.5 vs 19.1, P = 0.485). No significant difference was found in the FDG uptake of primary and metastatic foci between the DA and AA groups (P > 0.05).

CONCLUSION

Prostatic DA has greater PSMA uptake than BP diseases, but lower uptake in both primary foci and metastatic lymph nodes than AA on PSMA PET/CT, aiding in the differential diagnosis of DA, AA and BP diseases. Clinicians should combine traditional imaging with PSMA PET/CT to avoid underestimating the clinical stage of DA patients.

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).

Risk factor analysis and optimal cutoff value selection of PSAD for diagnosing clinically significant prostate cancer in patients with negative mpMRI: results from a high-volume center in Southeast China

BACKGROUND

Multi-parametric magnetic resonance imaging (mpMRI) is a diagnostic tool used for screening, localizing, and staging prostate cancer. Patients with Prostate Imaging Reporting and Data System (PI-RADS) score of 1 and 2 are considered negative mpMRI, with a lower likelihood of detecting clinically significant prostate cancer (csPCa). However, relying solely on mpMRI is insufficient to completely exclude csPCa, necessitating further stratification of csPCa patients using biomarkers.

METHODS

A retrospective study was conducted on mpMRI-negative patients who underwent prostate biopsy at the First Affiliated Hospital of Zhejiang University from January 2022 to June 2023. A total of 607 patients were included based on inclusion and exclusion criteria. Univariate and multivariate logistic regression analysis were performed to identify risk factors for diagnosing csPCa in patients with negative mpMRI. Receiver Operating Characteristic (ROC) curves were plotted to compare the discriminatory ability of different Prostate-Specific Antigen Density (PSAD) cutoff values for csPCa.

RESULTS

Among the 607 patients with negative mpMRI, 73 patients were diagnosed with csPCa. In univariate logistic regression analysis, age, PSA, f/tPSA, prostate volume, and PSAD were all associated with diagnosing csPCa in patients with negative mpMRI (P < 0.05), with PSAD being the most accurate predictor. In multivariate logistic regression analysis, f/tPSA, age, and PSAD were independent predictors of csPCa (P < 0.05). PSAD cutoff value of 0.20 ng/ml/ml has better discriminatory ability for predicting csPCa and is a significant risk factor for csPCa in multivariate analysis.

CONCLUSION

Age, f/tPSA, and PSAD are independent predictors of diagnosing csPCa in patients with negative mpMRI. It is suggested that patients with negative mpMRI and PSAD less than 0.20 ng/ml/ml could avoid prostate biopsy, as a PSAD cutoff value of 0.20 ng/ml/ml has better diagnostic performance than the traditional cutoff value of 0.15 ng/ml/ml.

Ductal prostate cancer staging: Role of PSMA PET/CT

INTRODUCTION

To evaluate the accuracy of PSMA PET/CT in the diagnosis and clinical staging of prostatic ductal adenocarcinoma (DAC).

MATERIALS AND METHODS

Two Caucasian men 58 and 62 years old were admitted to our Department for dysuria: the patients had not familiarity for prostate cancer (PCa), PSA values were 5.6 and 2.8 ng/ml, digital rectal examination was positive, multiparametric magnetic resonance image (mpMRI) showed for both the presence of an index lesion PIRADS score 5. The patients underwent extended transperineal prostate biopsy combined with four mpMRI/TRUS fusion biopsy under sedation and antibiotic prophylaxis; biopsy histology demonstrated the presence of a mixed PCa characterized by DAC and acinar PCa (Grade Group 4/Gleason score 8). The patients underwent clinical staging performing lung and abdominal CT, bone scan and fluoride 18 (18F) PSMA PET/CT.

RESULTS

Conventional imaging was negative for distant metastases; 18F-PSMA PET/CT showed in both patients an intraprostatic lesion characterized by a standardized uptake value (SUVmax) equal to 4.6 and 4.9 in the absence of distant lesions suspicious for metastases. Following multidisciplinary evaluation, the patients underwent radical prostatectomy plus extended pelvic lymphadenectomy. Definitive specimen showed the presence in both cases of a mixed pT3bN1 PCa (ductal plus acinar pattern Grade Group 4) with positive surgical margins, neuronal invasion, and nodes metastases (5/20 and 6/24, respectively). Post-operative PSA in the two patients was 0.8 and 0.3 ng/ml, therefore patients underwent adjuvant therapy.

CONCLUSIONS

Conventional imaging and PSMA PET/CT could result inadequate in clinical staging of DAC, the use of more imaging data (i.e. mpMRI and/or F-18 FDG) could improve overall accuracy.

Prostate cancer presentation and management in the Middle East

BACKGROUND

Although prostate cancer is a prevalent malignancy worldwide, its clinical presentation and management in the Middle East are not well-documented. This study aims to provide insights into the initial clinical presentation and management of prostate cancer in this region.

METHODS

A retrospective review was conducted on seven institutional databases from six Middle Eastern countries, including Türkiye, Lebanon, Iraq, Syria, Bahrain, and Jordan, to identify patients diagnosed with prostate cancer in 2021. Descriptive analysis was performed on the collected data to provide an overview of the demographic, clinical, and treatment variables.

RESULTS

A total of 1,136 patients were identified with a median age of 70 (range, 50-84). Most patients (78%) received their prostate cancer diagnosis after presenting with symptoms, as opposed to routine PSA screening. At the time of diagnosis, 35% of men had clinical T3 or T4 disease, 54% with Stage IV disease and 50% with Gleason score ≥ 8. Regarding treatment, 20% of non-metastatic and 22% of metastatic patients received no treatment.

CONCLUSION

Most men in this study sought prostate cancer evaluation due to symptoms and were subsequently diagnosed with advanced-stage disease, providing a foundation for future research aimed at understanding the underlying factors behind the observed trends and enabling informed interventions.

A Systematic Review on Prostate-Specific Membrane Antigen Positron Emission Tomography (PSMA PET) Evaluating Localized Low- to Intermediate-Risk Prostate Cancer: A Tool to Improve Risk Stratification for Active Surveillance?

Active surveillance remains a treatment option for low- to intermediate-risk prostate cancer (PCa) patients. Prostate-specific membrane antigen positron emission tomography and computed tomography (PSMA PET/CT) has emerged as a useful modality to assess intraprostatic lesions. This systematic review aims to evaluate PSMA PET/CT in localized low- to intermediate-risk PCa to determine its role in active surveillance. Following PRISMA guidelines, a search was performed on Medline, Embase, and Scopus. Only studies evaluating PSMA PET/CT in localized low- to intermediate-risk PCa were included. Studies were excluded if patients received previous treatment, or if they included high-risk PCa. The search yielded 335 articles, of which only four publications were suitable for inclusion. One prospective study demonstrated that PSMA PET/CT-targeted biopsy has superior diagnostic accuracy when compared to mpMRI. One prospective and one retrospective study demonstrated MRI occult lesions in 12.3-29% of patients, of which up to 10% may harbor underlying unfavorable pathology. The last retrospective study demonstrated the ability of PSMA PET/CT to predict the volume of Gleason pattern 4 disease. Early evidence demonstrated the utility of PSMA PET/CT as a tool in making AS safer by detecting MRI occult lesions and patients at risk of upgrading of disease.

68Ga-prostate specific membrane antigen-11 PET/CT versus multiparametric MRI in the detection of primary prostate cancer: A systematic review and head-to-head comparative meta-analysis

PURPOSE

The goal of this study was to evaluate the effectiveness of two diagnostic methods, 68Ga-PSMA-11 PET/CT and mpMRI, in detecting primary prostate cancer without limitations on the Gleason score.

METHODS

We conducted a comprehensive literature review, searching databases such as PubMed, Embase, and Web of Science until June 2023. Our objective was to identify studies that compared the efficacy of 68Ga-PSMA-11 PET/CT and mpMRI in detecting primary prostate cancer. To determine heterogeneity, the I2 statistic was used. Meta-regression analysis and leave-one-out sensitivity analysis were conducted to identify potential sources of heterogeneity.

RESULTS

Initially, 1286 publications were found, but after careful evaluation, only 16 studies involving 1227 patients were analyzed thoroughly. The results showed that the 68Ga-PSMA-11 PET/CT method had a pooled sensitivity and specificity of 0.87 (95 % CI: 0.80-0.92) and 0.80 (95 % CI: 0.69-0.89), respectively, for diagnosing prostatic cancer. Similarly, the values for mpMRI were determined as 0.84 (95 % CI: 0.75-0.92) and 0.74 (95 % CI: 0.61-0.86), respectively. There were no significant differences in diagnostic effectiveness observed when comparing two primary prostate cancer methodologies (pooled sensitivity P = 0.62, pooled specificity P = 0.50). Despite this, the funnel plots showed symmetry and the Egger test results (P values > 0.05) suggested there was no publication bias.

CONCLUSIONS

After an extensive meta-analysis, it was found that both 68Ga-PSMA-11 PET/CT and mpMRI demonstrate similar diagnostic effectiveness in detecting primary prostate cancer. Future larger prospective studies are warranted to investigate this issue further.

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.

Current role of PSMA-PET imaging in the clinical management of prostate cancer

Despite the developments of the last few years, metastatic castration-resistant prostate cancer (PC) remains a deadly disease. Until recently, almost all guidelines recommended magnetic resonance imaging (MRI) or computed tomography (CT) for the initial staging and local/systematic recurrence. Positron emission tomography/computed tomography (PET/CT) with prostate-specific membrane antigen (PSMA) at the present stage, emerged as a promising diagnostic imaging tool for PC. PSMA PET/CT alone or in combination with multiparametric magnetic resonance imaging (mpMRI) can improve the detection of clinically significant PC, especially for Prostate Imaging Reporting & Data System (PI-RADS) = 3 lesions. In addition, PSMA PET/CT is more accurate than CT and bone scan for intermediate to high-risk disease at the initial staging. Contrariwise, a negative PET is not useful for surgeons to avoid a pelvic nodal dissection. PET-PSMA imaging is appropriate for prostate-specific antigen (PSA) persistence or PSA rise from undetectable level after radical prostatectomy or for PSA rise above nadir after definitive radiotherapy. Also, it is recommended for patients fit for curative salvage treatment. It should be noted that in patients, candidates for radionuclide therapy with Lutetium-177 (117Lu), a PSMA strong expression from PET/CT at baseline is considered necessary. This review summarizes the evolution of PSMA PET/CT and its current role in the management of PC.