Prospective comparison of 18F-PSMA-1007 PET/CT, whole-body MRI and CT in primary nodal staging of unfavourable intermediate- and high-risk prostate cancer

18 F-prostate specific membrane antigen positron emission tomography/computerized tomography for lymph node staging in medium/high risk prostate cancer: A systematic review and meta-analysis

BACKGROUND

Lymph node staging of prostate cancer (PCa) is important for planning and monitoring of treatment. 18 F-prostate specific membrane antigen positron emission tomography/computerized tomography ( 18 F-PSMA PET/CT) has several advantages over 68 Ga-PSMA PET/CT, but its diagnostic value requires further investigation. This meta-analysis focused on establishing the diagnostic utility of 18 F-PSMA PET/CT for lymph node staging in medium/high-risk PCa.

METHODS

We searched the EMBASE, PubMed, Cochrane library, and Web of Science databases from inception to October 1, 2022. Prostate cancer, 18 F, lymph node, PSMA, and PET/CT were used as search terms and the language was limited to English. We additionally performed a manual search using the reference lists of key articles. Patients and study characteristics were extracted and the QUADAS-2 tool was employed to evaluate the quality of included studies. Sensitivity, specificity, the positive and negative likelihood ratio (PLR and NLR), diagnostic odds ratio (DOR), area under the curve (AUC), and 95% confidence interval (CI) were used to evaluate the diagnostic value of 18 F-PSMA PET/CT. Stata 17 software was employed for calculation and statistical analyses.

RESULTS

A total of eight diagnostic tests including 734 individual samples and 6346 lymph nodes were included in this meta-analysis. At the patient level, the results of each consolidated summary were as follows: sensitivity of 0.57 (95% CI 0.39-0.73), specificity of 0.95 (95% CI 0.92-0.97), PLR of 11.2 (95% CI 6.6-19.0), NLR of 0.46 (95% CI 0.31-0.68), DOR of 25 (95% CI 11-54), and AUC of 0.94 (95% CI 0.92-0.96). At the lesion level, the results of each consolidated summary were as follows: sensitivity of 0.40 (95% CI 0.21-0.62), specificity of 0.99 (95% CI 0.95-1.00), PLR of 40.0 (95% CI 9.1-176.3), NLR of 0.61 (95% CI 0.42-0.87), DOR of 66 (95% CI 14-311), and AUC of 0.86 (95% CI 0.83-0.89).

CONCLUSIONS

18 F-PSMA PET/CT showed moderate sensitivity but high specificity in lymph node staging of medium/high-risk PCa. The diagnostic efficacy was almost equivalent to that reported for 68 Ga-PSMA PET/CT.

REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), No. CRD42023391101.

De-Escalation of Therapy for Prostate Cancer

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men with around 1.4 million new cases every year. In patients with localized disease, management options include active surveillance (AS), radical prostatectomy (RP; with or without pelvic lymph node dissection), or radiotherapy to the prostate (with or without pelvic irradiation) with or without hormonotherapy. In advanced disease, treatment options include systemic treatment(s) and/or treatment to primary tumour and/or metastasis-directed therapies (MDTs). Specifically, in advanced stage, the current trend is earlier intensification of treatment such as dual or triple combination systemic treatments or adding treatment to primary and MDT to systemic treatment. However, earlier treatment intensification comes with the cost of increased morbidity and mortality resulting from drug-/treatment-related side effects. The main goal is and should be to provide the best possible care and oncologic outcomes with minimum possible side effects. This chapter will explore emerging possibilities to de-escalate treatment in PCa driven by enhanced insights into disease biology and the natural course of PCa such as AS in intermediate-risk disease or salvage versus adjuvant radiotherapy in post-RP patients. Considerations arising from advancements in PCa imaging and technological advancements in surgical and radiation therapy techniques including omitting pelvic lymph node dissection in the era of prostate-specific membrane antigen positron emitting tomography, the potential of MDT to delay/omit systemic treatment in metachronous oligorecurrence, and the efficacy of hypofractionation schemes compared with conventional fractionated radiotherapy will be discussed.

Diagnostic performance of 18F-labeled PSMA PET/CT in patients with biochemical recurrence of prostate cancer: a systematic review and meta-analysis

BACKGROUND

After initial treatment of prostate cancer, increases in prostate-specific antigen (PSA) levels commonly signify potential relapse or metastasis. 18F-labeled prostate-specific membrane antigen (PSMA) is considered a promising treatment due to its favorable physical properties.

PURPOSE

To investigate the diagnostic value of 18F-PSMA PET/CT for the recurrence and/or metastasis of biochemical recurrence of prostate cancer (BRPca).

MATERIAL AND METHODS

A comprehensive literature search was conducted in PubMed, EMBASE, Web of Science, and the Cochrane Library databases. Combined sensitivity and specificity values for the use of 18F-PSMA PET/CT in patients with BRPca were obtained. The quality of the studies was tested using the Diagnostic Accuracy Research Quality Assessment tool. Meta-analysis was performed using STATA 15 software, and heterogeneity was subsequently tested.

RESULTS

A total of 16 studies (1162 patients) were enrolled and had significant heterogeneity. The pooled sensitivity, specificity, and AUC values for 18F-PSMA PET/CT in the diagnosis of prostate recurrence and/or metastasis were 0.93 (0.89-0.95), 0.94 (0.85-0.98), and 0.96 (0,94-0.98), respectively. Meta-regression analyses showed that the sources of heterogeneity did not relate to ligands, study designs, or participants. The pooled sensitivity and specificity values of 18F-DCFPyL PET/CT were 0.90 (0.85-0.94) and 0.89 (0.85-0.93), respectively. The pooled sensitivity and specificity values of 18F-PSMA-1007 PET/CT were 0.89 (0.85-0.93) and 0.93 (0.70-0.99), respectively. The per-patient pooled sensitivity and specificity values were 0.92 (0.86-0.96) and 0.83 (0.41-0.97), respectively. The per-lesion pooled sensitivity and specificity values were 0.91 (0.86-0.94) and 0.91 (0.86-0.94), respectively.

CONCLUSION

According to our meta-analysis, 18F-PSMA PET/CT has the potential to be critical for the diagnosis of recurrence and/or metastasis in patients with BRPca.

Head-to-head Comparison of the Diagnostic Accuracy of Prostate-specific Membrane Antigen Positron Emission Tomography and Conventional Imaging Modalities for Initial Staging of Intermediate- to High-risk Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Whether prostate-specific membrane antigen positron emission tomography (PSMA-PET) should replace conventional imaging modalities (CIM) for initial staging of intermediate-high risk prostate cancer (PCa) requires definitive evidence on their relative diagnostic abilities.

OBJECTIVE

To perform head-to-head comparisons of PSMA-PET and CIM including multiparametric magnetic resonance imaging (mpMRI), computed tomography (CT) and bone scan (BS) for upfront staging of tumour, nodal, and bone metastasis.

EVIDENCE ACQUISITION

A search of the PubMed, EMBASE, CENTRAL, and Scopus databases was conducted from inception to December 2021. Only studies in which patients underwent both PSMA-PET and CIM and imaging was referenced against histopathology or composite reference standards were included. Quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) checklist and its extension for comparative reviews (QUADAS-C). Pairwise comparisons of the sensitivity and specificity of PSMA-PET versus CIM were performed by adding imaging modality as a covariate to bivariate mixed-effects meta-regression models. The likelihood ratio test was applied to determine whether statistically significant differences existed.

EVIDENCE SYNTHESIS

A total of 31 studies (2431 patients) were included. PSMA-PET/MRI was more sensitive than mpMRI for detection of extra-prostatic extension (78.7% versus 52.9%) and seminal vesicle invasion (66.7% versus 51.0%). For nodal staging, PSMA-PET was more sensitive and specific than mpMRI (73.7% versus 38.9%, 97.5% versus 82.6%) and CT (73.2% versus 38.5%, 97.8% versus 83.6%). For bone metastasis staging, PSMA-PET was more sensitive and specific than BS with or without single-photon emission computerised tomography (98.0% versus 73.0%, 96.2% versus 79.1%). A time interval between imaging modalities >1 month was identified as a source of heterogeneity across all nodal staging analyses.

CONCLUSIONS

Direct comparisons revealed that PSMA-PET significantly outperforms CIM, which suggests that PSMA-PET should be used as a first-line approach for the initial staging of PCa.

PATIENT SUMMARY

We reviewed direct comparisons of the ability of a scan method called PSMA-PET (prostate-specific membrane antigen positron emission tomography) and current imaging methods to detect the spread of prostate cancer outside the prostate gland. We found that PSMA-PET is more accurate for detection of the spread of prostate cancer to adjacent tissue, nearby lymph nodes, and bones.

Preoperative evaluation of prostate cancer by 68Ga-PMSA positron emission tomography/computed tomography: comparison with magnetic resonance imaging and with histopathological findings

Objective

To evaluate the accuracy of preoperative positron emission tomography/computed tomography with 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) for staging prostate cancer and compare it with magnetic resonance imaging (MRI) using histopathology of surgical specimens as the gold standard.

Materials and Methods

In this retrospective study, 65 patients with prostate cancer were analyzed.

Results

The accuracy of 68Ga-PSMA PET/CT for tumor detection was 95%, and that of MRI was 91%. There was no difference between 68Ga-PSMA PET/CT and MRI regarding localization of the lesion. The sensitivity of 68Ga-PSMA PET/CT for detecting extraprostatic extension was quite low (14%). For detection of seminal vesicle invasion, 68Ga-PSMA PET/CT showed a sensitivity of 57% and accuracy of 91%. There was a moderate correlation between the maximum standardized uptake value (SUVmax) and the serum level of prostate-specific antigen (p < 0.01; ρ = 0.368) and between the SUVmax and the International Society of Urological Pathology (ISUP) grade (p < 0.01; ρ = 0.513).

Conclusion

68Ga-PSMA PET/CT is a promising tool for detecting and evaluating the primary tumor, which can alter the staging and management of the disease.

Head-to-Head Comparison of 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT in Patients With Primary Prostate Cancer : A Pilot Study

PURPOSE

We aimed to compare the diagnostic performance of 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT in primary prostate cancer (PCa) patients.

PATIENTS AND METHODS

Thirty untreated primary PCa patients were enrolled. Each patient underwent 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT within a week. In addition to visual analysis, SUV was measured for semiquantitative comparison and correlation analysis.

RESULTS

68 Ga-P16-093 PET/CT detected more positive tumors than 68 Ga-PSMA-617 PET/CT (67 vs 56, P = 0.002), especially for intraprostatic lesions (29 vs 24, P = 0.025) and lymph node metastases (23 vs 17, P = 0.034). Further, 68 Ga-P16-093 PET/CT exhibited significantly higher SUV max of matched tumors (18.3 ± 14.4 vs 13.9 ± 11.8, P < 0.001). Besides, the SUV max of high-risk patients (based on D'Amico classification) on 68 Ga-P16-093 PET/CT was significantly higher than that of low- and intermediate-risk PCa patients (20.9 ± 9.9 vs 8.9 ± 9.1 vs 10.1 ± 5.2, P = 0.007). The SUV max of tumor measured by 68 Ga-P16-093 PET/CT had a moderate association with biopsy Gleason score ( r = 0.462, P = 0.005) and prostate-specific antigen value ( r = 0.491, P = 0.002), and significantly correlated with PSMA expression ( r = 0.732, P < 0.001).

CONCLUSIONS

68 Ga-P16-093 PET/CT exhibited higher tumor uptake and potentially better tumor detection capability than 68 Ga-PSMA-617 PET/CT, which suggested that 68 Ga-P16-093 may be more suitable in the diagnosis and staging of primary PCa patients.

Comparison of 18 F-PSMA-1007 PET/CT With 68 Ga-PSMA-11 PET/CT for Initial Staging in Intermediate- and High-Risk Prostate Cancer

PURPOSE

This study aimed to compare 18 F-PSMA-1007 PET/CT with 68 Ga-PSMA-11 PET/CT for initial staging in intermediate- and high-risk prostate cancer (PCa) patients.

METHODS

Forty treatment-naive, biopsy-proven, intermediate- or high-risk PCa patients were prospectively recruited. Each patient underwent PET/CT with 68 Ga-PSMA-11 and 18 F-PSMA-1007 (within 2 weeks). Assessment of both set of images included delineating number and characteristics of lesions, measurement of tracer uptake (SUV max ), miPSMA scoring, and PET-based stage categorization.

RESULTS

Intraprostatic lesions were detected in all patients by both tracers with concordant PET-based T stage. Median SUV max of the dominant PSMA-positive prostatic lesions was not significantly different with 18 F-PSMA-1007 and 68 Ga-PSMA-11 (19.9 vs 19.4, P = 0.127, n = 40). Prostatic miPSMA scores were similar in 31/40 (77.5%) patients with both tracers (weighted κ = 0.71). In 23/40 (57.5%) patients, regional lymph nodes (n = 171) were detected by both tracers. Few additional PET-positive regional lymph nodes (n = 3) were exclusively detected by 18 F-PSMA in 2 patients without altering PET-based N stage. Extraregional lymph nodes (n = 123 in 17/40 patients) and visceral metastatic lesions (n = 18 in 3/40 patients) were detected concordantly by both tracers. PET-positive marrow based and skeletal metastases (n = 71) were detected in 14/40 (35%) patients by both tracers. Few additional marrow and skeletal lesions (n = 7) were exclusively detected on 18 F-PSMA-1007 in 5/14 patients, potentially upstaging PET-based M stage in 2/5 patients. Both radiotracers showed excellent interreader agreement for region-wise detection of lesions.

CONCLUSIONS

Our results suggest that 18 F-PSMA-1007 PET/CT is comparable to 68 Ga-PSMA-11 PET/CT in detecting primary and metastatic lesions of PCa.

The Detection Performance of 18 F-Prostate-Specific Membrane Antigen-1007 PET/CT in Primary Prostate Cancer : A Systemic Review and Meta-analysis

BACKGROUND

Multiple tools are now available to determine the requirement for a biopsy to diagnose prostate cancer, and PET/CT with radiolabeled prostate-specific membrane antigen (PSMA)-targeting radiotracers has been recommended for detecting primary prostate cancer. Particularly, the radiotracer 18 F-PSMA-1007 was found to be more favorable for primary tumors compared with other PSMA-targeting radiotracers because of its low clearance via the urinary tract and better image resolution. Thus, we performed a systematic review and meta-analysis to more accurately evaluate the detection performance of 18 F-PSMA-1007 PET/CT in primary prostate cancer patients.

METHODS

An update on the databases of PubMed/MEDLINE, EMBASE, and Cochrane Library for comprehensive literature search was performed on September 30, 2021. The pooling detection rate was calculated on a per-patient basis. The pooling median of the SUV max was analyzed from the included studies. Furthermore, the positive predictive value of 18 F-PSMA-1007 PET/CT with pathologic lesions was analyzed using the criterion standard.

RESULTS

Twelve studies (540 patients total) were included in the meta-analysis. The overall pooling detection rate of 18 F-PSMA-1007 per patient was 94%, and the pooling median of SUV max located at the intraprostate tumor was 16 (range, 3.7-77.7). The positive predictive value of 18 F-PSMA-1007 per lesion with histopathological validation was 0.90, detecting regional lymph node metastasis was 0.94, and detecting localized prostatic tumors was 0.84.

CONCLUSIONS

In the current meta-analysis, we revealed the excellent performance of 18 F-PSMA-1007 to detect localized prostatic tumor lesions and regional lymph node metastasis. Moreover, the uptake of localized tumors in primary prostate cancer was nearly liver uptake and may be considered a suspicious malignancy if it was equal to or greater than the liver uptake.

The Role of PSMA PET/CT in the Primary Diagnosis and Follow-Up of Prostate Cancer-A Practical Clinical Review

Simple Summary

The combination of positron emission tomography (PET)-diagnostics with ligands binding to the prostate-specific membrane antigen (PSMA) has been a diagnostic milestone in the situation of biochemical recurrence of prostate cancer and is gaining importance in primary diagnostics, providing a highly specific and sensitive diagnostic method in various clinical situations. However, the clinical application of this method requires a comprehensive knowledge of its advantages and disadvantages, potential pitfalls and influencing factors. This review aims to provide a practical clinical review of the currently available background data on PSMA PET/CT, as well as the clinical implications. Although a large amount of data already exist, a thorough analysis is complicated by study heterogeneity, showing the need for future systematic and prospective research.

Abstract

The importance of PSMA PET/CT in both primary diagnostics and prostate cancer recurrence has grown steadily since its introduction more than a decade ago. Over the past years, a vast amount of data have been published on the diagnostic accuracy and the impact of PSMA PET/CT on patient management. Nevertheless, a large heterogeneity between studies has made reaching a consensus difficult; this review aims to provide a comprehensive clinical review of the available scientific literature, covering the currently known data on physiological and pathological PSMA expression, influencing factors, the differences and pitfalls of various tracers, as well as the clinical implications in initial TNM-staging and in the situation of biochemical recurrence. This review has the objective of providing a practical clinical overview of the advantages and disadvantages of the examination in various clinical situations and the body of knowledge available, as well as open questions still requiring further research.

Detection rate of fluorine-18 prostate-specific membrane antigen-1007 PET/CT for prostate cancer in primary staging and biochemical recurrence with different serum PSA levels: A systematic review and meta-analysis

Background

We performed a systematic review and meta-analysis to evaluate the detection rate (DR) of fluoro-prostate-specific membrane antigen (¹⁸F-PSMA-1007) PET/CT in patients with different serum prostate-specific antigen (PSA) levels in the setting of primary staging of prostate cancer (PCa) or biochemically recurring PCa.

Methods

A comprehensive electronic literature search of the PubMed, Embase, and Cochrane Library databases was conducted in accordance with the PRISMA statement. This study was registered in the PROSPERO database (registration number: CRD42022331595). We calculated the DR of ¹⁸F-PSMA-1007 PET/CT in PCa.

Results

The final analysis included 15 studies that described 1,022 patients and 2,034 lesions with ¹⁸F-PSMA-1007 PET/CT in PCa. The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in primary staging ranged from 90% to 100%, with a pooled estimate of 94% (95% CI: 92%–96%). The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in BCR ranged from 47% to 100%, with a pooled estimate of 86% (95% CI: 76%–95%). The DRs of PSA levels >2.0, 1.1–2.0, 0.51–1.0, and ≤0.5 ng/ml detected by ¹⁸F-PSMA-1007 PET/CT in a patient-based analysis were 97% (95% CI: 93%–99%), 95% (95% CI: 88%–99%), 79% (95% CI: 68%–88%), and 68% (95% CI: 58%–78%), respectively.

Conclusion

This meta-analysis concluded that ¹⁸F-PSMA-1007 PET/CT had a high application value for prostate cancer, including primary tumors and biochemical recurrence. The DR of ¹⁸F-PSMA-1007 PET/CT was slightly higher in primary prostate tumors than in biochemical recurrence.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022331595.

Management of Patients with Advanced Prostate Cancer: Report from the Advanced Prostate Cancer Consensus Conference 2021

BACKGROUND

Innovations in treatments, imaging, and molecular characterisation in advanced prostate cancer have improved outcomes, but various areas of management still lack high-level evidence to inform clinical practice. The 2021 Advanced Prostate Cancer Consensus Conference (APCCC) addressed some of these questions to supplement guidelines that are based on level 1 evidence.

OBJECTIVE

To present the voting results from APCCC 2021.

DESIGN, SETTING, AND PARTICIPANTS

The experts identified three major areas of controversy related to management of advanced prostate cancer: newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC), the use of prostate-specific membrane antigen ligands in diagnostics and therapy, and molecular characterisation of tissue and blood. A panel of 86 international prostate cancer experts developed the programme and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 107 pre-defined questions, which were developed by both voting and non-voting panel members prior to the conference following a modified Delphi process.

RESULTS AND LIMITATIONS

The voting reflected the opinions of panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results reported in the Supplementary material.

CONCLUSIONS

These voting results from a panel of experts in advanced prostate cancer can help clinicians and patients to navigate controversial areas of management for which high-level evidence is scant. However, diagnostic and treatment decisions should always be individualised according to patient characteristics, such as the extent and location of disease, prior treatment(s), comorbidities, patient preferences, and treatment recommendations, and should also incorporate current and emerging clinical evidence and logistic and economic constraints. Enrolment in clinical trials should be strongly encouraged. Importantly, APCCC 2021 once again identified salient questions that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference is a forum for discussing current diagnosis and treatment options for patients with advanced prostate cancer. An expert panel votes on predefined questions focused on the most clinically relevant areas for treatment of advanced prostate cancer for which there are gaps in knowledge. The voting results provide a practical guide to help clinicians in discussing treatment options with patients as part of shared decision-making.

Head-to-Head Comparison of 68Ga-PSMA-11 PET/CT and 99mTc-MDP Bone Scintigraphy for the Detection of Bone Metastases in Patients With Prostate Cancer: A Meta-Analysis

Background: Bone scintigraphy (BS) using 99mTc-MDP remains the recommended imaging modality for the detection of bone metastases in patients with prostate cancer (PCa). However, PET/CT using prostate-specific membrane antigen (PSMA) ligands is increasingly recognized for evaluating disease extent in patients with PCa, including as a possible standalone test in high-risk patients. Objective: To compare the diagnostic performance of 68Ga-PSMA-PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Evidence Acquisition: PubMed, Embase, and Cochrane Library databases were searched through October 2021 for studies reporting a head-to-head comparison of 68Ga-PSMA-PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Only studies with a well-defined reference standard (including various combinations of imaging and/or clinical follow-up) were included. Pooled diagnostic performance was calculated using bivariate random-effects model, and AUC was derived for each test from hierarchical summary ROC analysis. The two tests' complementary roles in identifying bone metastases in patients in whom the other test was negative were summarized. Evidence Synthesis: Six studies with 546 patients were included. The pooled sensitivity and specificity were 98% (95% CI: 94%-99%) and 97% (95% CI: 91%-99%) for 68Ga-PSMA-11 PET/CT versus 83% (95% CI: 69%-91%) and 68% (95% CI: 41%-87%) for 99mTc-MDP BS. The AUC was 0.99 (95% CI: 0.96-1.00) for 68Ga-PSMA-11 PET/CT and 0.85 (95% CI: 0.81-0.87) for 99mTc-MDP BS. In 408 patients from five included studies, 68Ga-PSMA-11 PET/CT correctly identified bone metastases in 43 (22.3%) of 193 patients with negative 99mTc-MDP BS results, whereas 99mTc-MDP BS correctly identified bone metastases in 4 (1.9%) of 210 patients with negative 68Ga-PSMA-11 PET/CT results. Conclusion: On a per-patient basis, 68Ga-PSMA-11 PET/CT has superior diagnostic performance than 99mTc-MDP BS for the detection of prostate cancer bone metastases. Furthermore, 99mTc-MDP BS offers limited additional information in patients with negative 68Ga-PSMA-11 PET/CT results. Clinical impact: According to current evidence, 99mTc-MDP BS is highly unlikely to be additive to 68Ga-PSMA-11 PET/CT in identifying bone metastases in patients with prostate cancer.

Radiolabeled PSMA Inhibitors

PSMA has shown to be a promising target for diagnosis and therapy (theranostics) of prostate cancer. We have reviewed developments in the field of radio- and fluorescence-guided surgery and targeted photodynamic therapy as well as multitargeting PSMA inhibitors also addressing albumin, GRPr and integrin αvβ3. An overview of the regulatory status of PSMA-targeting radiopharmaceuticals in the USA and Europe is also provided. Technical and quality aspects of PSMA-targeting radiopharmaceuticals are described and new emerging radiolabeling strategies are discussed. Furthermore, insights are given into the production, application and potential of alternatives beyond the commonly used radionuclides for radiolabeling PSMA inhibitors. An additional refinement of radiopharmaceuticals is required in order to further improve dose-limiting factors, such as nephrotoxicity and salivary gland uptake during endoradiotherapy. The improvement of patient treatment achieved by the advantageous combination of radionuclide therapy with alternative therapies is also a special focus of this review.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.

Comparison between 18 F-DCFPyL PET and MRI for the detection of transition zone prostate cancer

BACKGROUND

We aimed to compare the diagnostic performance of ¹⁸ F-DCFPyL positron emission tomography (PET) and multiparameter magnetic resonance imaging (mp-MRI) in detecting transition zone (TZ) prostate cancer (PCa).

METHODS

This retrospective study included 20 patients who underwent ¹⁸ F-DCFPyL PET/MRI and 32 patients who underwent ¹⁸ F-DCFPyL PET/CT and MRI from January 2019 to June 2020. All patients had TZ lesions and underwent prostate biopsies. One senior (reader 1) and one junior (reader 2) nuclear medicine physician evaluated each TZ lesion independently, according to the molecular imaging prostate-specific membrane antigen scoring system and the Prostate Imaging Reporting and Data System version 2.1 (PI-RADS v2.1). The histologic diagnosis of prostate biopsy was used as the reference standard. The diagnostic performance of the two methods was compared in terms of inter-reader agreement and area under the receiver operating characteristic (AUC-ROC) curve.

RESULTS

Of the 52 patients, 43 had TZ PCa. For inter-reader agreement, the kappa value was 0.883 for ¹⁸ F-DCFPyL PET and 0.393 for mp-MRI. For PET, both readers had the same diagnostic sensitivity, specificity, and accuracy of 93.0%, 77.8%, and 90.4%, respectively. For mp-MRI, the diagnostic sensitivity, specificity, and accuracy was 67.4%, 33.3%, and 61.5% for reader 1, and 51.2%, 44.4%, and 51.9% for reader 2, respectively. PET outperformed mp-MRI for both readers with an AUC of 0.872 for PET versus 0.584 for mp-MRI, p = .0209 for reader 1, and an AUC of 0.860 for PET versus 0.505 for mp-MRI, p = .0213 for reader 2. Among the 43 patients with TZ PCa, ¹⁸ F-DCFPyL PET detected a distant bone metastasis missed by the CT in one case and two small lymph node metastases missed by the CT and MRI in another case.

CONCLUSIONS

These results suggest that ¹⁸ F-DCFPyL PET, which was almost independent of the experience of the readers, was more objective in the evaluation of TZ lesions, and had higher diagnostic value than mp-MRI.

Molecular Imaging in Primary Staging of Prostate Cancer Patients: Current Aspects and Future Trends

Accurate primary staging is the cornerstone in all malignancies. Different morphological imaging modalities are employed in the evaluation of prostate cancer (PCa). Regardless of all developments in imaging, invasive histopathologic evaluation is still the standard method for the detection and staging of the primary PCa. Magnetic resonance imaging (MRI) and computed tomography (CT) play crucial roles; however, functional imaging provides additional valuable information, and it is gaining ever-growing acceptance in the management of PCa. Targeted imaging with different radiotracers has remarkably evolved in the past two decades. [111In]In-capromab pendetide scintigraphy was a new approach in the management of PCa. Afterwards, positron emission tomography (PET) tracers such as [11C/18F]choline and [11C]acetate were developed. Nevertheless, none found a role in the primary staging. By introduction of the highly sensitive small molecule prostate-specific membrane antigen (PSMA) PET/CT, as well as recent developments in MRI and hybrid PET/MRI systems, non-invasive staging of PCa is being contemplated. Several studies investigated the role of these sophisticated modalities in the primary staging of PCa, showing promising results. Here, we recapitulate the role of targeted functional imaging. We briefly mention the most popular radiotracers, their diagnostic accuracy in the primary staging of PCa, and impact on patient management.

Comparison of 68Ga-Prostate Specific Membrane Antigen (PSMA) Positron Emission Tomography Computed Tomography (PET-CT) and Whole-Body Magnetic Resonance Imaging (WB-MRI) with Diffusion Sequences (DWI) in the Staging of Advanced Prostate Cancer

Simple Summary

Precise staging is key for the optimal management of advanced prostate cancer. PSMA PET-CT and WB-MRI outperform standard imaging technology for staging high-risk prostate cancer, but direct comparison between both modalities is lacking. The primary endpoint of our study was to compare the diagnostic accuracy of both techniques in the detection of lymph node, bone and visceral metastases against a best valuable comparator (BVC), defined as a consensus adjudication of all lesions on the basis of baseline and follow-up imaging, biological and clinical data and histopathologic confirmation when available. Knowing the diagnostic accuracy of both next generation imaging modalities might influence the diagnostic and therapeutic strategy in prostate cancer by tailoring therapy. However, the impact on treatment and patient outcome of an improved detection of metastases has not been determined yet.

Abstract

Background: Prostate specific membrane antigen (PSMA) positron emission tomography computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) outperform standard imaging technology for the detection of metastasis in prostate cancer (PCa). There are few direct comparisons between both modalities. This paper compares the diagnostic accuracy of PSMA PET-CT and WB-MRI for the detection of metastasis in PCa. One hundred thirty-four patients with newly diagnosed PCa (n = 81) or biochemical recurrence after curative treatment (n = 53) with high-risk features prospectively underwent PSMA PET-CT and WB-MRI. The diagnostic accuracy of both techniques for lymph node, skeletal and visceral metastases was compared against a best valuable comparator (BVC). Overall, no significant difference was detected between PSMA PET-CT and WB-MRI to identify metastatic patients when considering lymph nodes, skeletal and visceral metastases together (AUC = 0.96 (0.92–0.99) vs. 0.90 (0.85–0.95); p = 0.09). PSMA PET-CT, however, outperformed WB-MRI in the subgroup of patients with newly diagnosed PCa for the detection of lymph node metastases (AUC = 0.96 (0.92–0.99) vs. 0.86 (0.79–0.92); p = 0.0096). In conclusion, PSMA PET-CT outperforms WB-MRI for the detection of nodal metastases in primary staging of PCa.

The Heterogeneous Metabolic Patterns of Ganglia in 68Ga-PSMA, 11C-choline, and 18F-FDG PET/CT in Prostate Cancer Patients

Purpose

Studies have indicated that PSMA-positive ganglia represent a diagnostic pitfall for nuclear medicine physicians. No studies have described choline and FDG uptake in ganglia, which may be a source of misdiagnosis. Herein, we described the percentage and uptake pattern of ⁶⁸Ga-PSMA, ¹¹C-choline and ¹⁸F-FDG PET/CT in ganglia and evaluated the heterogeneous metabolic patterns of ganglia to differentiate from lymph node metastases (LNM).

Methods

Thirty-nine patients who underwent ¹¹C-choline PET/CT and 120 patients who underwent ⁶⁸Ga-PSMA PET/CT and ¹⁸F-FDG PET/CT were retrospectively analyzed. The prevalence of PSMA-positive, choline-positive and FDG-positive ganglia was determined, the SUVmax of ganglia in different locations were measured, and the configuration was described. The SUVmax cutoff of PSMA-PET, choline-PET and FDG-PET was determined by ROC curve analysis to differentiate ganglia from LNM.

Results

329 PSMA-positive ganglia were identified in 120 patients, 95 choline-positive ganglia were identified in 39 patients, and 39 FDG-positive ganglia were identified in 34 patients. PSMA-positive uptake was observed in 98.3%, 95.8%, and 80.0% of cervical, coeliac, and sacral ganglia, respectively. Choline-positive uptake was observed in 84.6%, 97.4%, and 61.5% of cervical, coeliac, and sacral ganglia, respectively. FDG-positive uptake was observed in 16.7%, 13.3%, and 2.5% of cervical, coeliac, and sacral ganglia, respectively. Cervical and coeliac ganglia had a higher rate of PSMA-positive uptake than sacral ganglia. Choline uptake was highest in coeliac ganglia followed by cervical and sacral ganglia. PSMA, choline or FDG uptake in LNM was all significantly higher than ganglia. ROC curve analysis revealed that at a 4.1 SUVmax cutoff of PSMA-PET, the sensitivity, specificity and accuracy of LNM identification was 88.4%, 97.9% and 96.2%, respectively. ROC curve analysis revealed that at a 2.35 SUVmax cutoff for choline-PET, the sensitivity, specificity, and accuracy of LNM identification was 95.0%, 92.6% and 93.0%, respectively. ROC curve analysis revealed that at a 2.55 SUVmax cutoff for FDG-PET, the sensitivity, specificity, and accuracy of LNM identification was 77.3%, 87.2%, and 81.9%, respectively. PSMA-, Choline- and FDG-positive ganglia are mainly band-shaped; most LNMs exhibited nodular and teardrop-shaped configuration.

Conclusion

⁶⁸Ga-PSMA and ¹¹C-choline uptake in ganglia was common, and FDG-positive ganglia were observed at lower frequency. Using ⁶⁸Ga-PSMA, ¹¹C-choline and ¹⁸F-FDG uptake and anatomic location and configuration, the differentiation of ganglia from adjacent LNM is feasible.